Waste concrete adsorbent and preparation method thereof, and wastewater treatment system and device

Abstract

The invention belongs to the technical field of resource recycling, and particularly relates to a waste concrete adsorbent and a preparation method thereof, and a wastewater treatment system and device. The preparation method of the waste concrete adsorbent comprises the following steps: obtaining waste concrete, crushing and cleaning the waste concrete, and crushing the waste concrete to obtain concrete powder; performing acid impurity removal and activation treatment on the concrete powder to obtain activated concrete powder; and calcining the activated concrete powder, and crushing to obtain the waste concrete adsorbent. After the waste concrete is prepared into the waste concrete adsorbent by the preparation method disclosed by the embodiment of the invention, a larger surface area and more pore structures are exposed, so that the waste concrete adsorbent has higher physical adsorption capacity, and substances such as suspended solids, oil stains, organic pollutants and heavy metal ions in wastewater can be adsorbed and removed. Moreover, the waste is recycled, and the waste concrete powder is used for wastewater treatment, so that the stacking of the waste and the environmental burden can be reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of resource recycling, and in particular, relates to a waste concrete adsorbent and a preparation method thereof, and a wastewater treatment system and device. Background Art

[0002] Many traditional and high-tech methods have been used to treat wastewater. However, due to economic costs, some advanced water treatment technologies lack advantages in large-scale implementation. As a result, the application of waste adsorbents in wastewater treatment has attracted more and more attention. In addition to the requirements for wastewater treatment, more efficient waste management, circular economy, energy conservation and benign environmental impact are the main key drivers for using waste materials for wastewater treatment.

[0003] As the largest man-made material, concrete has occupied natural resources and caused negative impacts on the environment, which has also triggered discussions on sustainable development. The traditional method of dealing with waste concrete is mainly to transport it to the suburbs for storage or landfill, which not only costs a lot of transportation and causes secondary pollution to the environment, but also occupies a lot of precious land resources. Simply abandoning it is also a huge waste of natural resources.

[0004] The current market still lacks effective ways to recycle waste concrete. Summary of the invention

[0005] The purpose of the present application is to provide a waste concrete adsorbent and a preparation method thereof, a wastewater treatment system and a device, aiming to solve the problem of lack of effective resource utilization of waste concrete to a certain extent.

[0006] In order to achieve the above application purpose, the technical solution adopted in this application is as follows:

[0007] In a first aspect, the present application provides a method for preparing a waste concrete adsorbent, comprising the following steps:

[0008] Obtaining waste concrete, crushing and cleaning it, and then grinding it to obtain concrete powder;

[0009] Performing acidic impurity removal and activation treatment on the concrete powder to obtain activated concrete powder;

[0010] The activated concrete powder is calcined and crushed to obtain a waste concrete adsorbent.

[0011] In a second aspect, the present application provides a waste concrete adsorbent, which is prepared by the above-mentioned preparation method of the waste concrete adsorbent.

[0012] In a third aspect, the present application provides a wastewater treatment method, which uses the above-mentioned waste concrete adsorbent to treat wastewater, comprising the following steps:

[0013] Pre-treating wastewater using the waste concrete adsorbent to obtain pre-treated wastewater;

[0014] Using the waste concrete adsorbent and flocculant to perform physical precipitation treatment on the pre-treated wastewater to obtain precipitated wastewater;

[0015] Using the waste concrete adsorbent and the physical adsorbent to perform physical adsorption treatment on the precipitated wastewater to obtain adsorbed wastewater;

[0016] The adsorption wastewater is treated with chemical adsorption by using the waste concrete adsorbent and the chemical adsorbent, and then disinfected and tested to obtain qualified water.

[0017] In a fourth aspect, the present application provides a wastewater treatment system, comprising:

[0018] pretreatment systems to remove solid waste from wastewater;

[0019] Physical sedimentation systems to remove suspended solids from wastewater;

[0020] Physical adsorption systems for removing organic waste from wastewater;

[0021] Chemical adsorption systems for the removal of metal ions and / or toxic chemicals from wastewater;

[0022] Wherein, the above-mentioned waste concrete adsorbent is evenly added into the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system.

[0023] In a fifth aspect, the present application provides a wastewater treatment device used in the above-mentioned wastewater treatment system, comprising a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit connected in sequence; wherein,

[0024] The pretreatment unit is used to remove solid waste from wastewater;

[0025] The physical sedimentation unit is used to remove suspended matter in wastewater;

[0026] The physical adsorption unit is used to remove organic waste from wastewater;

[0027] The chemical adsorption unit is used to remove metal ions and / or toxic chemicals from wastewater.

[0028] The waste concrete adsorbent provided in the first aspect of the present application is used to crush and clean waste concrete to remove dirt, oil, plants and other impurities on the surface of the concrete. Then, the particle size is refined by pulverization, which helps to improve the subsequent impurity removal and activation effect. By subjecting the concrete powder to acidic impurity removal and activation treatment, cement residues, metal pollutants, chlorides, sulfates, microbial pollutants and other impurity components in the waste concrete are further removed, and chemical impurities in the waste concrete itself are removed. At the same time, the surface of the waste concrete is activated by acid to enhance its adsorption capacity. By calcining the activated concrete powder, the chemical activity of the surface of the concrete powder is improved, new active sites are generated, the surface hydrophilicity is improved, the microstructure of the concrete powder is improved, the porosity and microcracks of the concrete powder are increased, and the adsorption and exchange of heavy metal ions are promoted.

[0029] The waste concrete adsorbent prepared by the above method of the present application has a large surface area and rich pore structure, and thus has a strong physical adsorption capacity, and can adsorb and remove suspended matter, oil pollution, organic pollutants, heavy metal ions and other substances in wastewater. It can also remove suspended matter and some organic matter in wastewater through flocculation. In addition, the waste concrete adsorbent also contains a certain amount of calcium compounds and other components, which can react with some pollutants in the wastewater, especially with some heavy metal ions to undergo ion exchange reactions and remove them from the wastewater.

[0030] The present application adopts the above-mentioned waste concrete adsorbent to treat wastewater, and adopts the waste concrete adsorbent to pre-treat wastewater to remove impurities such as solid waste. Then, the waste concrete adsorbent and flocculant are used to perform physical precipitation treatment on the pre-treated wastewater to remove impurities such as suspended matter in the wastewater. The waste concrete adsorbent and physical adsorbent are used to perform physical adsorption treatment on the precipitated wastewater to remove impurities such as organic waste in the wastewater by adsorption. The waste concrete adsorbent and chemical adsorbent are used to perform chemical adsorption treatment on the adsorbed wastewater to remove impurities such as heavy metal ions and toxic chemicals in the wastewater by adsorption. After the wastewater is treated with the above-mentioned waste concrete adsorbent in sequence through a series of treatments such as pre-treatment, physical precipitation treatment, physical adsorption treatment, chemical adsorption treatment, and disinfection, impurities in the wastewater can be removed, so that the wastewater is converted into qualified water that can be used normally. The resource utilization of waste concrete is realized, and waste concrete is introduced into the field of water treatment.

[0031] The wastewater treatment system of the present application includes a pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system which are connected in sequence, and the above-mentioned waste concrete adsorbent is evenly added to the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system. The solid waste in the pretreatment system, the suspended matter in the physical precipitation system, the organic waste in the physical adsorption system, and the metal ions and / or toxic chemicals in the chemical adsorption system are removed in sequence by the above-mentioned waste concrete adsorbent. The resource utilization of waste concrete is realized, and waste concrete is introduced into the field of water treatment. At the same time, the adsorption process is monitored and controlled by an intelligent system, which improves work efficiency and realizes the large-scale utilization of waste concrete.

[0032] The wastewater treatment device of the present application is suitable for the above-mentioned wastewater treatment system, and includes a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit connected in sequence. These units can fully remove impurities in the wastewater, so that the wastewater can be recycled and utilized as a resource. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0034] Figure 1 It is a schematic flow chart of a method for preparing a waste concrete adsorbent provided in an embodiment of the present application;

[0035] Figure 2 It is a schematic diagram of the process of the wastewater treatment method provided in the embodiment of the present application;

[0036] Figure 3 is a schematic diagram of a wastewater treatment system provided in an embodiment of the present application;

[0037] Figure 4 It is a schematic diagram of a pretreatment system in a wastewater treatment system provided in an embodiment of the present application;

[0038] Figure 5 It is a schematic diagram of a physical precipitation system in a wastewater treatment system provided in an embodiment of the present application;

[0039] Figure 6 is a schematic diagram of a physical adsorption system in a wastewater treatment system provided in an embodiment of the present application;

[0040] Figure 7 It is a schematic diagram of a chemical adsorption system in a wastewater treatment system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0041] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present application more clearly understood, the present application is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0042] In this application, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0043] In this application, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b or c", or "at least one of a, b and c", can all represent: a, b, c, ab (i.e. a and b), ac, bc, or abc, where a, b, c can be single or multiple, respectively.

[0044] It should be understood that in the various embodiments of the present application, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0045] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0046] The weight of the relevant components mentioned in the embodiments of the present specification can not only refer to the specific content of each component, but also represent the proportional relationship between the weights of the components. Therefore, as long as the content of the relevant components in the embodiments of the present specification is proportionally enlarged or reduced, it is within the scope disclosed in the embodiments of the present specification. Specifically, the mass described in the embodiments of the present specification can be μg, mg, g, kg and other mass units known in the chemical industry.

[0047] The terms "first" and "second" are used only for descriptive purposes to distinguish objects such as substances from each other, and should not be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX may also be referred to as the second XX, and similarly, the second XX may also be referred to as the first XX. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0048] The first aspect of the present application provides a method for preparing a waste concrete adsorbent, as shown in the attached Figure 1 As shown, the following steps are included:

[0049] S10. Obtain waste concrete, crush and clean it, and then pulverize it to obtain concrete powder;

[0050] S20. The concrete powder is subjected to acidic impurity removal and activation treatment to obtain an activated concrete powder;

[0051] S30. calcining the activated concrete powder and crushing it to obtain a waste concrete adsorbent.

[0052] The waste concrete adsorbent provided in the first aspect of the embodiment of the present application is used to crush and clean the waste concrete to remove dirt, oil, plants and other impurities on the surface of the concrete. Then, the particle size is refined by pulverization, which helps to improve the subsequent impurity removal and activation effect. By subjecting the concrete powder to acidic impurity removal and activation treatment, the impurity components such as cement residues, metal pollutants, chlorides, sulfates, microbial pollutants, etc. in the waste concrete are further removed, the chemical impurities in the waste concrete itself are removed, and the surface of the waste concrete is activated by acid to enhance its adsorption capacity. By calcining the activated concrete powder, the chemical activity of the surface of the concrete powder is improved, new active sites are generated, the surface hydrophilicity is improved, the microstructure of the concrete powder is improved, the porosity and microcracks of the concrete powder are increased, and the adsorption and exchange of heavy metal ions are promoted.

[0053] Therefore, after the waste concrete is made into the waste concrete adsorbent by the preparation method of the embodiment of the present application, a larger surface area and more pore structures are exposed, which makes it have a stronger physical adsorption capacity. Therefore, the waste concrete adsorbent can remove suspended matter, oil pollution, organic pollutants and heavy metal ions in the wastewater by surface adsorption. The waste concrete adsorbent can aggregate small particles in the wastewater through flocculation to form larger particles (flocs), which are easy to settle or filter out, thereby removing suspended matter and some organic matter in the wastewater. In addition, the waste concrete adsorbent contains a certain amount of calcium compounds and other components, which have certain chemical reactivity and can react with some pollutants in the wastewater, especially with some heavy metal ions (such as lead, copper, cadmium, etc.) to perform ion exchange reactions to remove them from the wastewater. Exemplarily, calcium ions can combine with heavy metal ions in water to form insoluble hydroxides or carbonates, which are removed. In addition, the waste concrete adsorbent has certain environmental protection as a wastewater treatment material, because it is the recycling of waste, and by using waste concrete powder for wastewater treatment, the stacking of waste and the environmental burden can be reduced.

[0054] In the above step S10, the collected waste concrete is added to the crusher, crushed and then sent to the concrete washer; the crushed concrete is cleaned to remove the surface dirt, oil, plants and other impurities. The crushed and cleaned concrete is crushed again and sieved to obtain concrete powder.

[0055] In some possible implementations, after crushing and cleaning, the average particle size of the waste concrete is greater than 0 and not higher than 1 mm. For example, the average particle size can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, and other typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values. In this case, it is convenient to clean, and if the crushing is too small, the waste concrete is easily lost during the crushing process.

[0056] In some possible implementations, the average particle size of the concrete powder is greater than 0 and not greater than 0.5 mm; for example, the average particle size of the concrete powder can be any typical but non-limiting point value such as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or an interval value between any two point values. In this case, it is helpful to promote the progress of the subsequent acidic impurity removal reaction and improve the activation efficiency.

[0057] In some possible implementations, some cement components (such as cement particles, gypsum, aluminum silicate, etc.), metal pollutants, chlorides, sulfates, microbial pollutants, etc. may remain in the waste concrete, and these cement components will affect the concrete's treatment effect on wastewater.

[0058] The above step S20: adding concrete powder into the acidic impurity removal liquid to remove chemical impurities such as cement components, metal pollutants, chlorides, sulfates, microbial pollutants, etc. in the waste concrete, and at the same time acid-activating the surface of the waste concrete to enhance its adsorption capacity.

[0059] In some possible implementations, the step of acidic impurity removal and activation treatment includes: mixing concrete powder with an acidic solution having a concentration of 5 mol / L to 7 mol / L. Exemplarily, the acidic solution can be any typical but non-limiting point value such as 5 mol / L, 6 mol / L, 7 mol / L, or an interval value between any two point values. In this case, the impurity components can be effectively removed and the adsorption capacity of the concrete powder can be activated without excessively destroying the structure of the concrete in the present application.

[0060] In some possible implementations, the acidic solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. These acidic solutions can remove chemical impurities in concrete powder, and improve the adsorption capacity of concrete powder, thereby activating the concrete powder.

[0061] The embodiment of the present application can effectively remove organic matter, dust and dirt on the surface of waste concrete by acidic impurity removal and activation treatment of concrete powder. These organic matters may occupy the adsorption sites on the surface of concrete and interfere with its adsorption. By acid washing, the surface can be cleaned, more active sites are exposed, and a larger surface area is provided for the subsequent adsorption process. On the other hand, the surface of concrete is corroded by the reaction of acidic solution with waste concrete, and more pores or microcracks are formed on its surface. These tiny pores provide more adsorption space for pollutants (such as heavy metal ions and suspended matter) in wastewater, thereby enhancing the adsorption capacity. This effect is not only a physical increase in pores, but may also be accompanied by an increase in specific surface area, greatly improving the adsorption capacity of waste concrete. On the other hand, acid activation can also change the chemical properties of the surface of waste concrete. The main components contained in concrete are calcium compounds (such as CaO, Ca(OH)2, CaCO3, etc.). When concrete reacts with acid, the acidic solution can react with these calcium compounds to form soluble salts (such as calcium chloride, calcium sulfate, etc.) or hydration products, and may expose more calcium oxide and calcium ions. These calcium ions have strong hydrophilicity and can adsorb certain heavy metal ions (such as Pb 2+ 、Cd 2+ , Cu 2+ In addition, after acid activation, the hydroxide ions (OH -) concentration may also increase, which can promote the removal of heavy metal ions in water. In addition, acid activation can also make the surface of waste concrete carry more negative charges. When the acidic solution reacts with the calcium salt in the concrete, it may cause more hydroxyl groups (OH - ) or oxygen ions (O 2- ), so that the concrete surface is negatively charged. For some positively charged pollutants in wastewater (such as certain metal ions), the acid-activated concrete surface can enhance the adsorption capacity of these ions through electrostatic attraction.

[0062] The above step S30: calcining the activated concrete powder to enhance the activity of the concrete powder itself.

[0063] In some possible implementations, the conditions for the calcination treatment include: heating to 300°C to 400°C at a rate of 10°C / h to 20°C / h under an inert atmosphere, and keeping warm for 12 to 36 hours. In this case. The activity of the concrete powder can be fully improved. High-temperature drying under an inert atmosphere (such as nitrogen or argon) avoids the occurrence of oxidation reactions and maintains the stability of the surface of the waste concrete. Compared with oxygen in the air, an inert atmosphere can prevent excessive oxidation of concrete, ensure that its physical structure is not destroyed, and retain its chemical reactivity. Such an atmosphere helps to control harmful by-products produced during high-temperature processes, thereby maximizing the adsorption capacity of waste concrete.

[0064] The present application embodiment performs calcination treatment on activated concrete powder. Under high temperature conditions, the microstructure of the waste concrete will change. High temperature can promote the opening of micropores and cracks inside the concrete, increase its porosity, and thus increase the specific surface area of ​​the waste concrete. This provides more space for the adsorption of pollutants, thereby increasing its activity. High temperature drying may cause the generation of microcracks on the surface of the concrete, which can become adsorption sites for more pollutants, further enhancing its adsorption capacity. The hydration products (such as calcium hydroxide, calcium silicate hydrate, etc.) in the waste concrete will undergo a transformation process at high temperature, resulting in changes in its structure and properties: high temperature can dehydrate some of the hydration products (such as calcium hydroxide) in the concrete to form more stable calcium oxide (CaO). Calcium oxide has strong hydrophilicity and chemical reactivity, and can react chemically with some pollutants in wastewater, especially adsorb heavy metal ions or exchange ions with pollutants in water. Silicate hydration products may undergo certain structural rearrangements at high temperatures, making them more porous and more chemically reactive, thereby enhancing the adsorption capacity of concrete. In addition, high temperature can cause changes in the chemical activity of the concrete surface. Specifically, at high temperatures, some chemical bonds on the concrete surface may break, exposing more active sites (such as calcium oxide and silicon oxygen bonds) and generating new active sites. These active sites can better adsorb pollutants in wastewater, especially positively charged heavy metal ions (such as Pb 2+ 、Cd 2+ , Cu 2+ After high temperature treatment, the surface hydrophilicity of concrete may be improved, making it better able to adsorb ions and organic pollutants dissolved in water.

[0065] Exemplarily, the calcination treatment is carried out under an inert atmosphere such as nitrogen, argon, helium, etc. The heating rate can be 10°C / h, 12°C / h, 15°C / h, 18°C / h, 20°C / h, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values; the holding temperature can be 300°C, 320°C, 350°C, 380°C, 400°C, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values; the holding time can be 12 hours, 15 hours, 18 hours, 20 hours, 22 hours, 24 hours, 30 hours, 34 hours, 36 hours, etc., typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values.

[0066] In some possible implementations, the average particle size of the waste concrete adsorbent is greater than 0 and not higher than 0.1 mm, and can be any typical but non-restrictive point value or an interval value between any two point values ​​such as 0.01 mm, 0.02 mm, 0.03 mm, 0.05 mm, 0.06 mm, 0.08 mm, and 0.1 mm. In this case, the specific surface area of ​​the adsorbent in contact with wastewater during the subsequent wastewater treatment of the waste concrete adsorbent is increased, thereby enhancing the adsorption capacity.

[0067] In a second aspect, an embodiment of the present application provides a waste concrete adsorbent, and the waste concrete adsorbent is prepared by the above-mentioned preparation method of the waste concrete adsorbent.

[0068] The waste concrete adsorbent prepared by the above method in the embodiment of the present application has a large surface area and rich pore structure, and thus has a strong physical adsorption capacity, and can adsorb and remove suspended matter, oil pollution, organic pollutants, heavy metal ions and other substances in wastewater. It can also remove suspended matter and some organic matter in wastewater through flocculation. In addition, the waste concrete adsorbent also contains a certain amount of calcium compounds and other components, which can react with some pollutants in the wastewater, especially with some heavy metal ions to undergo ion exchange reactions and remove them from the wastewater.

[0069] In a third aspect, the present application provides a method for treating wastewater, as shown in the attached Figure 2 As shown, the above-mentioned waste concrete adsorbent is used to treat wastewater, including the following steps:

[0070] S40. Pretreating the wastewater using a waste concrete adsorbent to obtain pretreated wastewater;

[0071] S50. Using waste concrete adsorbent and flocculant to perform physical precipitation treatment on the pretreated wastewater to obtain precipitated wastewater;

[0072] S60. Using waste concrete adsorbent and physical adsorbent to physically adsorb the wastewater after precipitation to obtain adsorbed wastewater;

[0073] S70. Use waste concrete adsorbent and chemical adsorbent to chemically adsorb the adsorbed wastewater, disinfect it and test it to obtain qualified water.

[0074] The embodiment of the present application adopts the above-mentioned waste concrete adsorbent to treat wastewater, and adopts the waste concrete adsorbent to pre-treat the wastewater to remove impurities such as solid waste. Then, the pre-treated wastewater is subjected to physical precipitation treatment by the waste concrete adsorbent and flocculant to remove impurities such as suspended matter in the wastewater. The waste concrete adsorbent and physical adsorbent are used to perform physical adsorption treatment on the precipitated wastewater to remove impurities such as organic waste in the wastewater by adsorption. The adsorbed wastewater is subjected to chemical adsorption treatment by the waste concrete adsorbent and chemical adsorbent to remove impurities such as heavy metal ions and toxic chemicals in the wastewater by adsorption. After the wastewater is subjected to a series of treatments such as pre-treatment, physical precipitation treatment, physical adsorption treatment, chemical adsorption treatment, and disinfection by the above-mentioned waste concrete adsorbent, impurities in the wastewater can be removed, so that the wastewater is converted into qualified water that can be used normally. The resource utilization of waste concrete is realized, and waste concrete is introduced into the field of water treatment.

[0075] The above step S40: pre-treating the wastewater with the waste concrete adsorbent, during which the waste concrete adsorbent is directly added to the wastewater to promote the precipitation of solid wastes, followed by filtering to filter out larger solid impurities to obtain pre-treated wastewater.

[0076] In some possible implementations, the mass ratio of the waste concrete adsorbent to the wastewater is 1:(8-12). Exemplarily, the mass ratio of the waste concrete adsorbent to the wastewater can be 1:8, 1:9, 1:10, 1:11, 1:12, and other typical but non-limiting arbitrary point values ​​or interval values ​​between any two point values. In this case, it can be fully ensured that the solid waste in the wastewater is removed.

[0077] The above step S50: using the waste concrete adsorbent and flocculant to perform physical precipitation treatment on the pre-treated wastewater, and removing suspended matter in the wastewater through flocculation.

[0078] In some possible implementations, the mass ratio of the waste concrete adsorbent and the flocculant is (1-3):1, which can be any typical but non-restrictive point value such as 1:1, 1:2, 1:3, or an interval value between any two point values. In this case, the suspended solids in the wastewater can be better removed by flocculation. If the proportion of the waste concrete adsorbent is too high, it may cause excessive sediment in the water, thereby increasing the burden on subsequent treatment processes (such as sedimentation and filtration). Excessive concentration of the waste concrete adsorbent may cause resuspension of some sediments or blockage of the filtration system. In addition, if the proportion of the waste concrete adsorbent is too low, it may result in poor removal of larger particles in the wastewater, especially poor removal of some coarse particles and sediments. Excessive use of flocculants may result in excessive flocculant residues, which in turn affects the water quality and requires additional post-treatment.

[0079] In some possible implementations, the flocculant includes at least one of alum, aluminum sulfate, and polyaluminum chloride; these substances can all have a flocculating effect on suspended matter in the wastewater, and can aggregate small particles in the wastewater to form larger particles (flocs) for easy sedimentation or filtration, thereby removing suspended matter and some organic matter in the wastewater.

[0080] In some embodiments, the physical precipitation treatment is followed by filtration treatment, and the filter residue is subjected to filter pressing treatment. After heating and drying, it can be used as a recycled concrete raw material.

[0081] The above step S60: using waste concrete adsorbent and physical adsorbent to perform physical adsorption treatment on the wastewater after precipitation, so as to adsorb and remove impurities such as organic waste in the wastewater.

[0082] In some possible implementations, the mass ratio of the waste concrete adsorbent and the physical adsorbent is (1-2):1; specifically, it can be 1:1, 1:2, etc. In this case, large and small particles of organic pollutants in the wastewater can be fully adsorbed and removed. Too much waste concrete adsorbent will lead to incomplete removal of fine organic pollutants in the wastewater. If the proportion of physical adsorbent is too low, it may lead to poor removal of fine organic pollutants (such as soluble organic matter, dyes, etc.). If the proportion of waste concrete adsorbent is too high, it may lead to excessive sedimentation, affecting the subsequent treatment of the wastewater (such as sedimentation, filtration, etc.). When the proportion of waste concrete adsorbent is low, the removal of large particles is insufficient, and suspended matter and larger particles in the wastewater may not be effectively removed, affecting the treatment effect.

[0083] In some possible implementations, the physical adsorbent includes at least one of activated carbon, natural zeolite, charcoal, and activated silica; all of these substances have high active specific surface areas and strong adsorption capacity for organic pollutants in wastewater. In some preferred embodiments, the physical adsorbent is selected from activated carbon.

[0084] In some possible implementations, the optimal particle size of the physical adsorbent particles is generally 0.3 mm to 0.6 mm, and can specifically be any typical but non-restrictive point value such as 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, or an interval value between any two point values, which can ensure a good adsorption effect and provide suitable fluidity.

[0085] In some embodiments, the physical adsorption treatment is followed by filtration treatment, and the organic matter in the treated water is tested. If qualified, it enters the next treatment stage, and if unqualified, it undergoes physical adsorption treatment again. The filter residue is subjected to filter pressing treatment, and after heating and drying, it can be used as a recycled concrete raw material.

[0086] The above step S70: using waste concrete adsorbent and chemical adsorbent to perform chemical adsorption treatment on the adsorption wastewater, through chemical adsorption and reaction to help heavy metal ions (Pb 2+ Cr 3+ 、Cd 2+ , Cu 2+ 、Zn 2+ 、As 3+ The insoluble precipitates are filtered out and the insoluble precipitates are filtered through a filter press to remove impurities such as heavy metal ions and toxic chemicals.

[0087] In some possible implementations, the mass ratio of the waste concrete adsorbent to the chemical adsorbent is 3:(1-3), which can be any typical but non-restrictive point value such as 3:1, 3:2, 3:3, or an interval value between any two point values. In this case, the adsorption and removal of heavy metal ions and toxic chemicals in wastewater can be fully ensured.

[0088] In some possible implementations, the chemical adsorbent includes an iron salt and an aluminum salt in a mass ratio of (2 to 4): 1. Exemplarily, the mass ratio of the iron salt and the aluminum salt can be any typical but non-restrictive point value such as 2:1, 3:1, 4:1, or an interval value between any two point values. In this case, the adsorption and removal of heavy metal ions and toxic chemicals in the wastewater can be fully ensured. Too high a ratio of iron salts may lead to the generation of excessive precipitates, which not only increases the amount of solid waste in the wastewater, but may also burden the subsequent filtration and dehydration processes. Too high a ratio of aluminum salts will lead to the generation of too much aluminum hydroxide precipitation, affecting the clarification effect of the water, and may also lead to an increase in the residual aluminum concentration in subsequent treatments, which will have an adverse effect on the environment. By controlling the ratio of the waste concrete adsorbent, iron salts, and aluminum salts, the adsorption and removal of impurity components in the wastewater can be ensured, and the introduction of additional impurity components can be avoided.

[0089] In some embodiments, the iron salt includes ferric chloride, ferrous sulfate, etc.; the aluminum salt includes polyaluminum chloride, aluminum sulfate, etc.

[0090] In some embodiments, the waste concrete adsorbent is usually rich in mineral components, especially silicates and calcium compounds in cement. These components give concrete good physical adsorption properties, especially in removing particulate matter, suspended matter and partially soluble heavy metal ions. Concrete adsorbents interact with particulate matter and soluble heavy metal ions in wastewater through surface adsorption. These substances can be fixed on the surface of concrete adsorbents through van der Waals forces, hydrogen bonds and other physical adsorption forces. Calcium ions in concrete can undergo ion exchange reactions with certain metal ions in wastewater to remove heavy metal ions such as lead, copper, and cadmium. The porous structure of the concrete surface provides a large amount of surface area, which enables it to effectively capture particulate matter and pollutants in water and reduce the concentration of suspended solids. Iron salts play a critical role as flocculants and precipitants in wastewater treatment, especially in removing soluble metal ions and particulate matter in water. After dissolving, iron salts (such as ferrous sulfate and ferric chloride) release trivalent iron ions, which combine with suspended particles or organic matter in water to form larger flocs. The formation of flocs helps to increase the settling rate of particulate matter, making it easier to remove by precipitation or filtration. Iron salts can also react with heavy metal ions (such as lead, copper, zinc, etc.) in water to form insoluble metal hydroxides or iron-metal complexes, thereby effectively removing these harmful substances. 3+ With Pb 2+ It can react to form a precipitated iron-lead complex. Iron salts (especially divalent iron) also have reducing properties and can reduce certain heavy metal ions (such as hexavalent chromium) to low-toxic or insoluble trivalent metals), thereby reducing their toxicity. The working principle of aluminum salts (such as alum and aluminum sulfate) is mainly to remove heavy metals and particulate matter in wastewater through flocculation and precipitation reactions. Aluminum salts release Al after dissolution. 3+ Ions, which can combine with suspended particles in water to form larger flocs. These flocs are easier to remove by sedimentation or filtration. Aluminum salts are particularly effective in removing organic and inorganic particles in water. Aluminum salts react with heavy metal ions (such as lead, cadmium, copper, etc.) to form insoluble aluminum hydroxide complexes or aluminum heavy metal precipitates, thereby removing these harmful substances. For example, aluminum salts react with Pb 2+ The lead hydroxide precipitate formed can effectively remove lead from water. Aluminum salts can also adjust the pH of water through neutralization and optimize subsequent treatment effects.

[0091] In some embodiments, the synergistic effect of the waste concrete adsorbent, iron salts and aluminum salts includes: iron salts and aluminum salts can combine with suspended matter and heavy metal ions in wastewater by generating larger and heavier flocs, while the waste concrete adsorbent can adsorb more pollutants through its surface. The combination of the two can improve the removal efficiency of particulate matter. The precipitates formed by iron salts and aluminum salts in water can interact with the surface of concrete adsorbents, further promoting the removal of heavy metal ions and particulate matter. Calcium compounds and other mineral components of concrete may help fix and settle these precipitates to prevent them from re-entering the water body. The presence of concrete adsorbents can enhance the effects of iron salts and aluminum salts, providing more surface sites to capture and adsorb heavy metal ions and harmful substances in water.

[0092] In some embodiments, the chemical adsorption treatment is followed by filtration treatment, and the heavy metal ion content and toxic chemical substance content in the treated water are tested respectively. If the test is qualified, it will enter the next treatment link, and if the test is unqualified, the chemical adsorption treatment will be performed again. The filter residue is subjected to filter pressing treatment, and after heating and drying, it can be used as a recycled concrete raw material.

[0093] In some possible implementations, disinfection uses chlorination to kill bacteria, viruses and other pathogenic microorganisms in wastewater, ensure the safety of treated water, and prevent the spread of disease.

[0094] In some possible implementations, water quality testing is performed, and qualified water, i.e. normal water, is obtained after passing the test. The chemical oxygen demand in qualified water is less than 15 mg / L; suspended solids are less than 25 mg / L; chloride is less than 250 mg / L; total dissolved solids are less than 1000 mg / L; and the total amount of heavy metal ions is ≤3.0 mg / L.

[0095] In some embodiments, the chemical oxygen demand (COD, mainly monitoring the degree of organic pollution) in qualified water is: <15 mg / L, suspended solids (SS, mainly detecting the content of solid particulate matter): <25 mg / L, chloride (Cl - ):<250mg / L, Total dissolved solids (TDS):<1000mg / L, Heavy metal ions: Lead (Pb 2+ ): ≤0.01mg / L, mercury (Hg 2+ ): ≤0.0005mg / L, cadmium (Cd 2+ ): ≤0.005mg / L, copper (Cu 2+ ): ≤1.0mg / L, zinc (Zn 2+ ):≤1.0mg / L, iron (Fe 2+ / Fe 3+ ): ≤1.0mg / L, nickel (Ni 2 + ):≤0.05mg / L, chromium (Cr3+ / Cr 6+ ): ≤0.05mg / L, cobalt (Co 2+ ): ≤0.05mg / L, antimony (Sb 3+ ): ≤0.005mg / L, arsenic (As 3+ / As 5+ ): ≤0.05mg / L.

[0096] In a fourth aspect, the present application provides a wastewater treatment system, as shown in the attached Figure 3 As shown, including the sequentially connected:

[0097] pretreatment systems to remove solid waste from wastewater;

[0098] Physical sedimentation systems to remove suspended solids from wastewater;

[0099] Physical adsorption systems for removing organic waste from wastewater;

[0100] Chemical adsorption systems for the removal of metal ions and / or toxic chemicals from wastewater;

[0101] The above-mentioned waste concrete adsorbent is evenly added into the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system.

[0102] The wastewater treatment system of the embodiment of the present application includes a pretreatment system, a physical precipitation system, a physical adsorption system and a chemical adsorption system which are connected in sequence, and the above-mentioned waste concrete adsorbent is evenly added to the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system. The solid waste in the pretreatment system, the suspended matter in the physical precipitation system, the organic waste in the physical adsorption system, and the metal ions and / or toxic chemicals in the chemical adsorption system are removed in sequence by the above-mentioned waste concrete adsorbent. The resource utilization of waste concrete is realized, and waste concrete is introduced into the field of water treatment. At the same time, the adsorption process is monitored and controlled by an intelligent system, which improves the work efficiency and realizes the large-scale utilization of waste concrete.

[0103] In some embodiments, the pretreatment system is as follows Figure 4 As shown in the figure, the wastewater first passes through the screen to remove larger solid particles such as plastic, wood chips, leaves, gravel, etc., and then flows into the grit chamber to use the change in water flow velocity to make heavier particles (such as sand, soil, etc.) settle to the bottom of the tank. In this process, the waste concrete adsorbent is directly added to the water to promote the precipitation of solid waste. It is then filtered to filter out larger solid impurities.

[0104] In some embodiments, the pretreatment system needs to monitor the flow rate of the wastewater through the screen to prevent the flow rate from being too fast and the solid waste from damaging the screen too fast. For a coarser screen (such as a pore size of 1 to 3 mm), the flow rate should generally not exceed 1 m / s to 2 m / s. For a finer screen (such as a pore size of about 0.2 mm), the flow rate should be controlled within 0.5 m / s to avoid excessive pressure on the screen, especially when there are more suspended matter or solid particles in the wastewater.

[0105] In some embodiments, the flow rate of wastewater entering the grit chamber in the pretreatment system is monitored to prevent the flow rate from being too fast and affecting the precipitation of solid waste. For the flow rate of water entering the sedimentation chamber, in order to ensure the sedimentation effect, the flow rate is preferably controlled between 0.3 m / s and 0.5 m / s. Specifically, 0.3 m / s can be used.

[0106] In some embodiments, the flow rate of wastewater through the filter press in the pretreatment system is monitored to prevent the flow rate from being too fast and the solid waste from damaging the filter press. Generally speaking, the feed flow rate should not exceed 2 m / s to 3 m / s, and should be appropriately adjusted according to the specific wastewater conditions and the specifications of the filter press. Specifically, 2 m / s can be used.

[0107] In some embodiments, the quality of the product in the screen and the filter press in the pretreatment system is monitored. After reaching the set point, the container is opened to automatically collect the leached concrete aggregate therein to prevent excessive clogging of the wet screen and the filter press by the product, thereby affecting subsequent filtration. Appropriate adjustments are made according to the specific wastewater conditions and the specifications of the filter press and the screen, so as not to clog the screen and the filter press. When the system detects that the product is too much and clogging the screen and the filter press, stop pumping wastewater into the sand settling tank. After the system detects that the blockage is eliminated, the system automatically restarts to proceed to the subsequent steps.

[0108] In some possible implementations, the physical precipitation system is further added with at least one flocculant selected from alum, aluminum sulfate, and polyaluminum chloride; in conjunction with the waste concrete adsorbent, the suspended solids in the wastewater are better removed.

[0109] In some embodiments, physical precipitation such as attachment Figure 5 As shown, after pretreatment, the wastewater is pumped into a physical sedimentation tank. At this stage, most of the suspended solids in the wastewater are removed by natural sedimentation. The solid particles in the wastewater (such as silt and suspended matter) settle to the bottom of the tank due to gravity. This step can remove most of the suspended matter and some heavier particulate pollutants. In this process, the concrete adsorbent is mixed with flocculants such as alum, aluminum sulfate, and polyaluminum chloride in a ratio of (1 to 3): 1 to promote the flocculation of suspended matter and particulate matter, accelerate sedimentation, and improve the removal efficiency. Subsequently, a filtration treatment is performed to filter out the flocculants, and the flocculants are filtered through a filter press, and then heated and dried to obtain the raw materials for preparing recycled concrete.

[0110] In some embodiments, the flow rate of wastewater entering the physical sedimentation tank in the physical sedimentation system is monitored to prevent the flow rate from being too fast and affecting the precipitation of flocs. The flow rate of wastewater passing through the filter press in the physical sedimentation system is monitored to prevent the flow rate from being too fast and the flocs from damaging the filter press too fast. The quality of the product in the filter press in the physical sedimentation system is monitored. After reaching the set point, the container is opened to automatically collect the precipitate therein to prevent excessive precipitate from clogging the filter press and affecting subsequent filtration. When the system detects that too much product is clogging the filter press, the pumping of wastewater is stopped. After the system detects that the blockage is eliminated, the system automatically restarts to proceed to the subsequent steps.

[0111] In some possible implementations, the physical adsorption system is further added with at least one physical adsorbent selected from the group consisting of activated carbon, natural zeolite, charcoal, and activated silica; and cooperates with the waste concrete adsorbent to remove organic waste from the wastewater.

[0112] In some embodiments, a physical adsorption system such as Figure 6 As shown, after physical precipitation, the wastewater flows into the physical adsorption tank to adsorb organic matter and some heavy metal ions in the wastewater. In this process, the concrete adsorbent is mixed with physical adsorbents such as activated carbon, natural zeolite, charcoal, activated silica, etc. in a ratio of (1-2):1 and added to the system to improve the adsorption speed and removal efficiency. Then, the solid precipitate is filtered out, and the solid precipitate is filtered through a filter press, and then heated and dried to obtain the raw material for preparing recycled concrete.

[0113] In some embodiments, the flow rate of wastewater entering the physical sedimentation tank in the physical adsorption system is monitored to prevent the flow rate from being too fast and affecting the solid precipitation rate. The flow rate of wastewater passing through the filter press in the physical adsorption system is monitored to prevent the flow rate from being too fast and the solid precipitation rate from being too fast and damaging the filter press. The quality of the product in the filter press in the physical adsorption system is monitored. After reaching the set point, the container is opened to automatically collect the precipitate therein to prevent excessive precipitation from clogging the filter press and affecting subsequent filtration. When the system detects that too much product clogs the filter press, pumping of the wastewater is stopped. After the system detects that the blockage has been eliminated, the system automatically restarts to proceed to the subsequent steps. Monitor the concentration of organic matter in the wastewater passing through the filter press. When the concentration does not meet the requirements, the wastewater is re-introduced into the physical adsorption tank for physical adsorption.

[0114] In some possible implementations, iron salt and aluminum salt are further added to the chemical adsorption system in a mass ratio of (2-4): 1. The waste concrete adsorbent is used in conjunction with the waste concrete adsorbent to remove metal ions and / or toxic chemicals in the wastewater.

[0115] In some embodiments, a chemical adsorption system such as Figure 7As shown, after physical adsorption, the wastewater flows into the chemical adsorption tank, and the adsorbent is added to react with the pollutants and heavy metal ions in the wastewater to form insoluble precipitates, which are then removed by precipitation. In this process, the concrete adsorbent is mixed with iron salts (ferrous sulfate (FeSO4, etc.) and aluminum salts (aluminum sulfate (Al2(SO4)3, etc.) in a ratio of 3: (1~2): (1~2), which helps the heavy metal ions (Pb 2+ ,Cr 3+ , Cd 2+ , Cu 2+ , Zn 2 + , As 3+ The insoluble precipitate is filtered out by a filter press, and then heated and dried to obtain the raw material for preparing recycled concrete.

[0116] In some embodiments, the flow rate of the wastewater entering the physical sedimentation tank in the chemical adsorption system is monitored to prevent the flow rate from being too fast and affecting the precipitation rate of the insoluble precipitate. The flow rate of the wastewater passing through the filter press in the chemical adsorption system is monitored to prevent the flow rate from being too fast and the insoluble precipitate from damaging the filter press too fast. The product quality in the filter press in the chemical adsorption system is monitored. After reaching the set point, the container is opened to automatically collect the precipitate therein to prevent excessive precipitation from clogging the filter press and affecting subsequent filtration. When the system detects that too much product clogs the filter press, the pumping of the wastewater is stopped. After the system detects that the blockage has been eliminated, the system automatically restarts to proceed to the subsequent steps. Monitor the concentration of heavy metal ions in the wastewater passing through the filter press. When the concentration does not meet the requirements, the wastewater is re-introduced into the physical adsorption tank for physical adsorption.

[0117] In some possible implementations, a disinfection system and a water quality detection system are also included after the chemical adsorption system, wherein the disinfection system is used to disinfect the water. In some embodiments, chlorination disinfection is performed to kill bacteria, viruses and other pathogenic microorganisms in the wastewater to ensure the safety of the treated water and prevent the spread of diseases.

[0118] In a fifth aspect, an embodiment of the present application provides a wastewater treatment device used in the above-mentioned wastewater treatment system, comprising a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit connected in sequence; wherein,

[0119] The pretreatment unit is used to remove solid waste from wastewater;

[0120] Physical sedimentation units are used to remove suspended solids from wastewater;

[0121] Physical adsorption units are used to remove organic waste from wastewater;

[0122] Chemical adsorption units are used to remove metal ions and / or toxic chemicals from wastewater.

[0123] The wastewater treatment device of the embodiment of the present application is suitable for the above-mentioned wastewater treatment system, and includes a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit connected in sequence. These units can fully remove impurities in the wastewater, so that the wastewater can be recycled and utilized as a resource.

[0124] In order to make the above implementation details and operations of the present application clearly understood by those skilled in the art, as well as to significantly demonstrate the improved performance of the waste concrete adsorbent and its preparation method, wastewater treatment system and device in the embodiments of the present application, the above technical scheme is illustrated by multiple embodiments below.

[0125] Example 1

[0126] A waste concrete adsorbent, such as Figure 1 As shown, its preparation comprises the steps of:

[0127] 2kg of waste concrete was crushed and passed through a 1mm sieve, then soaked and filtered in water for 6 hours, then crushed again and passed through a 0.5mm sieve. The concrete was then soaked in a 0.1mol / L dilute hydrochloric acid solution for 6 hours for acid activation, and after the powder was filtered, it was placed in a dryer, heated to 300°C at a rate of 10°C / h in a nitrogen atmosphere, and dried for 24 hours. The concrete was then placed in a ball mill, crushed and passed through a 0.1mm sieve to obtain a waste concrete adsorbent.

[0128] A method for treating wastewater using waste concrete adsorbent, such as Figure 2 As shown in the attached Figure 3 The wastewater treatment system shown comprises the following steps:

[0129] 1. Pretreatment: The wastewater is first filtered through a screen at a flow rate of 0.5 m / s, and then flows into a sand settling tank to allow heavier particles to settle, and then filtered.

[0130] 2. Physical sedimentation treatment: After pretreatment, the wastewater is pumped into the physical sedimentation tank at a speed of 0.5m / s. The solid particles in the wastewater (such as silt and suspended matter) are precipitated to the bottom of the tank due to gravity. In this process, 500g of concrete adsorbent is mixed with 250g of alum in a ratio of 2:1 and added to the sedimentation tank. After precipitation for 4 hours, it is filtered to filter the flocculants, and the flocculants are filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0131] 3. Physical adsorption treatment: After physical precipitation treatment, the wastewater flows into the physical adsorption tank at a speed of 0.5m / s. In this process, 500g of concrete adsorbent and 500g of activated carbon are mixed in a ratio of 1:1 and added to the tank. After precipitation for 3 hours, it is then filtered to filter the solid precipitate, and the solid precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0132] 4. Chemical adsorption treatment: After physical adsorption treatment, the wastewater flows into the chemical adsorption tank at a speed of 0.5m / s. In this process, 600g of concrete adsorbent is mixed with 200g of ferrous sulfate (FeSO4) and 200g of aluminum sulfate (Al2(SO4)3)) in a ratio of 3:1:1, added to the sedimentation tank, and after precipitation for 1h, it is filtered to filter the insoluble precipitate, and the insoluble precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0133] 5. After chemical adsorption treatment, it was found that the oxygen content, suspended matter and heavy metal ion concentration in the water were all qualified and met the requirements.

[0134] Example 2

[0135] A waste concrete adsorbent, such as Figure 1 As shown, its preparation comprises the steps of:

[0136] 2kg of waste concrete was crushed and passed through a 1mm sieve, then soaked and filtered in water for 6 hours, then crushed again and passed through a 0.5mm sieve. The concrete was then soaked in a 0.1mol / L dilute hydrochloric acid solution for 6 hours for acid activation, and after the powder was filtered, it was placed in a dryer and heated to 300°C at a rate of 10°C / h under a nitrogen atmosphere and dried for 24 hours. The concrete was then placed in a ball mill and crushed and passed through a 0.1mm sieve to obtain a waste concrete adsorbent.

[0137] A method for treating wastewater using waste concrete adsorbent, such as Figure 2 As shown in the attached Figure 3 The wastewater treatment system shown comprises the following steps:

[0138] 1. Pretreatment: The wastewater is first filtered through a screen at a flow rate of 0.5 m / s, and then flows into a sand settling tank to allow heavier particles to settle, and then filtered.

[0139] 2. Physical sedimentation treatment: After pretreatment, the wastewater is pumped into the physical sedimentation tank at a speed of 1m / s. The solid particles in the wastewater (such as silt and suspended matter) are precipitated to the bottom of the tank due to gravity. In this process, 500g of concrete adsorbent is mixed with 250g of alum (Al2(SO4)3) in a ratio of 2:1 and added to the sedimentation tank. After precipitation for 4 hours, it is filtered to filter the flocculants, and the flocculants are filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0140] 3. Physical adsorption treatment: After physical precipitation treatment, the wastewater flows into the physical adsorption tank at a speed of 1m / s. In this process, 500g of concrete adsorbent and 500g of zeolite are mixed in a ratio of 1:1 and added to the tank. After precipitation for 3 hours, it is then filtered to filter the solid precipitate, and the solid precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0141] 4. Chemical adsorption treatment: After physical adsorption treatment, the wastewater flows into the chemical adsorption tank at a speed of 1m / s. In this process, 600g of concrete adsorbent is mixed with 200g of ferric chloride (FeCl3) and 200g of polyaluminium chloride (Al2(OH)6Cl3) in a ratio of 3:1:1, added to the sedimentation tank, and after precipitation for 1h, it is filtered to filter the insoluble precipitate, and the insoluble precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0142] 5. After chemical adsorption treatment, it was found that the oxygen content, suspended matter and heavy metal ion concentration in the water were all qualified and met the requirements.

[0143] Example 3

[0144] A waste concrete adsorbent, such as Figure 1 As shown, its preparation comprises the steps of:

[0145] 2kg of waste concrete was crushed and passed through a 1mm sieve, then soaked and filtered in water for 6 hours, then crushed again and passed through a 0.5mm sieve. The concrete was then soaked in a 0.1mol / L dilute hydrochloric acid solution for 6 hours for acid activation, and after the powder was filtered, it was placed in a dryer, heated to 400°C at a rate of 15°C / h in a nitrogen atmosphere, and dried for 24 hours. The concrete was then placed in a ball mill, crushed and passed through a 0.1mm sieve to obtain a waste concrete adsorbent.

[0146] A method for treating wastewater using waste concrete adsorbent, such as Figure 2 As shown in the attached Figure 3 The wastewater treatment system shown comprises the following steps:

[0147] 1. Pretreatment: The wastewater is first filtered through a screen at a flow rate of 0.5 m / s, and then flows into a sand settling tank to allow heavier particles to settle, and then filtered.

[0148] 2. Physical sedimentation treatment: After pretreatment, the wastewater is pumped into the physical sedimentation tank at a speed of 0.5m / s. The solid particles in the wastewater (such as silt and suspended matter) are precipitated to the bottom of the tank due to gravity. In this process, 500g of concrete adsorbent is mixed with 250g of alum in a ratio of 2:1 and added to the sedimentation tank. After precipitation for 4 hours, it is filtered to filter the flocculants, and the flocculants are filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0149] 3. Physical adsorption treatment: After physical precipitation treatment, the wastewater flows into the physical adsorption tank at a speed of 0.5m / s. In this process, 500g of concrete adsorbent and 500g of activated carbon are mixed in a ratio of 1:1 and added to the tank. After precipitation for 3 hours, it is then filtered to filter the solid precipitate, and the solid precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0150] 4. Chemical adsorption treatment: After physical adsorption treatment, the wastewater flows into the chemical adsorption tank at a speed of 0.5m / s. In this process, 600g of concrete adsorbent is mixed with 200g of ferrous sulfate (FeSO4) and 200g of aluminum sulfate (Al2(SO4)3) in a ratio of 3:1:1, added to the sedimentation tank, and after precipitation for 1h, it is filtered to filter the insoluble precipitate, and the insoluble precipitate is filtered through a filter press. The filter residue is then heated and dried, and can be used as a raw material for preparing recycled concrete.

[0151] 5. After chemical adsorption treatment, it was found that the oxygen content, suspended matter and heavy metal ion concentration in the water were all qualified and met the requirements.

[0152] Comparative Example 1

[0153] A method for treating wastewater comprises the following steps:

[0154] 1. The wastewater is first filtered through the screen at a flow rate of 0.5m / s, and then flows into the sand settling tank to allow the heavier particles to settle, and then filtered.

[0155] 2. After that, the wastewater is pumped into the physical sedimentation tank at a speed of 0.5m / s. The solid particles (such as silt and suspended matter) in the wastewater settle to the bottom of the tank due to gravity. In this process, 750g of alum is added to the sedimentation tank. After settling for 4h, it is filtered.

[0156] 3. The wastewater then flows into the physical adsorption tank at a speed of 0.5 m / s. During this process, 1000 g of activated carbon is added to the tank and allowed to settle for 3 hours. It is then filtered.

[0157] 3. The wastewater then flows into the chemical adsorption tank at a speed of 0.5 m / s. During this process, 500 g of ferrous sulfate (FeSO4) and 500 g of aluminum sulfate (Al2(SO4)3) are mixed in a ratio of 1:1 and added to the sedimentation tank. After precipitation for 1 hour, it is filtered.

[0158] 4. Subsequent testing found that the oxygen content and suspended matter in the water met the requirements, but the heavy metal ion concentration did not meet the requirements.

[0159] In order to verify the progress of the embodiments of the present application, the water treated by the above embodiments and comparative examples was tested, and the test results are shown in Table 1 below:

[0160] Table 1

[0161] Example 1 Example 2 Example 3 Comparative Example 1 Chemical oxygen demand mg / L 5.254 5.765 6.131 23.241 Suspended matter mg / L 3.236 4.324 3.451 31.731 Chloride mg / L 5.312 7.313 7.641 8.763 Total dissolved solids mg / L 13.417 16.432 27.738 63.644 <![CDATA[Lead (Pb 2+ ) mg / L]]> 0 0 0 0.006 <![CDATA[Mercury (Hg 2+ ) mg / L]]> 0 0 0 0 <![CDATA[Cadmium (Cd 2+ ) mg / L]]> 0 0 0 0.005 <![CDATA[Copper (Cu 2+ ) mg / L]]> 0.102 0.253 0.379 1.341 <![CDATA[Zinc (Zn 2+ ) mg / L]]> 0.031 0.115 0.192 0.545 <![CDATA[Iron (Fe 2+ / Fe 3+ ) mg / L]]> 0.183 0.243 0.423 1.252 <![CDATA[Nickel (Ni 2+ ) mg / L]]> 0.011 0.028 0.036 0.054 <![CDATA[Chromium (Cr 3+ / Cr 6+ ) mg / L]]> 0.131 0.253 0.325 1.221 <![CDATA[Cobalt (Co 2+ ) mg / L]]> 0.021 0.033 0.037 0.063 <![CDATA[Antimony (Sb 3+ ) mg / L]]> 0 0 0 0.004 <![CDATA[Arsenic (As 3+ / As 5+ ) mg / L]]> 0 0 0.003 0.006

[0162] From the test results in Table 1 above, it can be seen that the embodiment of the present application uses the prepared waste concrete adsorbent to synergistically treat wastewater, and the oxygen content, suspended matter, and heavy metal ion concentration in the treated water are all qualified and meet the requirements, and can be used normally. However, Comparative Example 1 does not use the waste concrete adsorbent to synergistically treat wastewater, and the heavy metal ion concentration in the treated water is still high, and the effluent is unqualified.

[0163] The above description is only a preferred embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A method for preparing a waste concrete adsorbent, characterized in that: The following steps are involved: Obtaining waste concrete, crushing and cleaning it, and then grinding it to obtain concrete powder; Performing acidic impurity removal and activation treatment on the concrete powder to obtain activated concrete powder; The activated concrete powder is calcined and crushed to obtain a waste concrete adsorbent.

2. The method for preparing the waste concrete adsorbent according to claim 1, characterized in that: The step of acidic impurity removal and activation treatment comprises: mixing the concrete powder with an acidic solution having a concentration of 5 mol / L to 7 mol / L; And / or, the calcination treatment conditions include: in an inert atmosphere, heating to 300° C. to 400° C. at a rate of 10° C. / h to 20° C. / h, and keeping the temperature for 12 to 36 hours.

3. The method for preparing the waste concrete adsorbent according to claim 2, characterized in that: After the crushing and cleaning process, the average particle size of the waste concrete is greater than 0 and not higher than 1 mm; and / or, the average particle size of the concrete powder is greater than 0 and not higher than 0.5 mm; and / or, the average particle size of the waste concrete adsorbent is greater than 0 and not higher than 0.1 mm; And / or, the acidic solution includes at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

4. A waste concrete adsorbent, characterized in that: The waste concrete adsorbent is prepared by the preparation method of the waste concrete adsorbent according to any one of claims 1 to 3.

5. A method for treating wastewater, characterized in that: The wastewater treatment using the waste concrete adsorbent as claimed in claim 4 comprises the following steps: Pre-treating wastewater using the waste concrete adsorbent to obtain pre-treated wastewater; Using the waste concrete adsorbent and flocculant to perform physical precipitation treatment on the pre-treated wastewater to obtain precipitated wastewater; Using the waste concrete adsorbent and the physical adsorbent to perform physical adsorption treatment on the precipitated wastewater to obtain adsorbed wastewater; The adsorption wastewater is treated with chemical adsorption by using the waste concrete adsorbent and the chemical adsorbent, and then disinfected and tested to obtain qualified water.

6. The wastewater treatment method according to claim 5, characterized in that: The mass ratio of the waste concrete adsorbent to the wastewater is 1:(8-12) and / or, the mass ratio of the waste concrete adsorbent to the flocculant is (1-3):1; And / or, the flocculant includes at least one of alum, aluminum sulfate, and polyaluminum chloride; and / or, the mass ratio of the waste concrete adsorbent to the physical adsorbent is (1-2):1; And / or, the physical adsorbent includes at least one of activated carbon, natural zeolite, charcoal, and activated silica; and / or, the mass ratio of the waste concrete adsorbent to the chemical adsorbent is 3:(1-3); And / or, the chemical adsorbent comprises iron salt and aluminum salt in a mass ratio of (2-4):1; And / or, the disinfection is carried out by chlorination.

7. The wastewater treatment method according to claim 5 or 6, characterized in that: The qualified water contains chemical oxygen demand <15mg / L; suspended solids <25mg / L; chloride <250mg / L; total dissolved solids <1000mg / L; and total heavy metal ion content ≤3.0mg / L.

8. A wastewater treatment system, characterized in that: Including the following connected in sequence: pretreatment systems to remove solid waste from wastewater; Physical sedimentation systems to remove suspended solids from wastewater; Physical adsorption systems for removing organic waste from wastewater; Chemical adsorption systems for the removal of metal ions and / or toxic chemicals from wastewater; Wherein, the waste concrete adsorbent as claimed in claim 4 is uniformly added to the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system.

9. The wastewater treatment system according to claim 8, characterized in that: After the chemical adsorption system, a disinfection system and a water quality detection system are also included, wherein the disinfection system is used to disinfect the water; And / or, the physical precipitation system further contains at least one flocculant selected from the group consisting of alum, aluminum sulfate, and polyaluminum chloride; And / or, the physical adsorption system is further added with at least one physical adsorbent selected from the group consisting of activated carbon, natural zeolite, charcoal, and activated silica; And / or, the chemical adsorption system further contains iron salt and aluminum salt in a mass ratio of (2-4):

1.

10. A wastewater treatment device used in the wastewater treatment system according to any one of claims 8 to 9, characterized in that: It includes a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit which are connected in sequence; wherein, The pretreatment unit is used to remove solid waste from wastewater; The physical sedimentation unit is used to remove suspended matter in wastewater; The physical adsorption unit is used to remove organic waste from wastewater; The chemical adsorption unit is used to remove metal ions and / or toxic chemicals from wastewater.

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