Waste concrete adsorbent, method for preparing same, and wastewater treatment system and device

Abstract

The application belongs to the technical field of resource recycling, and particularly relates to a waste concrete adsorbent, a preparation method thereof, a wastewater treatment system and a device. The preparation method of the waste concrete adsorbent comprises the following steps: obtaining waste concrete, crushing and cleaning the waste concrete to obtain concrete powder; performing acid impurity removal and activation treatment on the concrete powder to obtain activated concrete powder; and performing calcination treatment on the activated concrete powder to obtain the waste concrete adsorbent. After the waste concrete is prepared into the waste concrete adsorbent by the preparation method of the application, a large surface area and more pore structures are exposed, which makes the waste concrete adsorbent have strong physical adsorption capacity and can adsorb and remove suspended solids, oil stains, organic pollutants, heavy metal ions and other substances in wastewater. Moreover, the application is a recycling of waste, and by using the waste concrete powder for wastewater treatment, the stacking and environmental burden of waste can be reduced.

Description

TECHNICAL FIELD

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

[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. Therefore, the application of waste adsorbents in wastewater treatment has attracted more and more attention. In addition to the requirements for wastewater treatment, more effective waste management, circular economy, energy saving and benign environmental impact are the main key driving factors for using waste to treat wastewater.

[0003] The use of concrete, the largest man-made material, has caused a discussion on the sustainable development problem due to the occupation of natural resources and the negative impact on the environment. The traditional treatment method of waste concrete is mainly to transport it to the suburbs for stacking or landfill, which not only costs a lot of transportation fees and causes secondary pollution to the environment, but also occupies a large amount of valuable land resources, and simply discarding it is also a great waste of natural resources.

[0004] At present, there is still a lack of effective way to resource utilization of waste concrete in the market. SUMMARY

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

[0006] To achieve the above application purposes, the technical solutions adopted by the present application are as follows:

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

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

[0009] Carrying out acid impurity removal and activation treatment on the concrete powder to obtain activated concrete powder;

[0010] Carrying out calcination treatment on the activated concrete powder, and then pulverizing 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 preparation method of the waste concrete adsorbent.

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

[0013] The waste water is pretreated by using the waste concrete adsorbent to obtain pretreated waste water;

[0014] The pretreated waste water is physically precipitated by using the waste concrete adsorbent and a flocculant to obtain precipitated waste water;

[0015] The precipitated waste water is physically adsorbed by using the waste concrete adsorbent and a physical adsorbent to obtain adsorbed waste water;

[0016] The adsorbed waste water is chemically adsorbed by using the waste concrete adsorbent and a chemical adsorbent, and then disinfected and detected to obtain qualified water.

[0017] In a fourth aspect, the application provides a waste water treatment system, comprising sequentially connected:

[0018] a pretreatment system for removing solid waste in waste water;

[0019] a physical precipitation system for removing suspended matter in waste water;

[0020] a physical adsorption system for removing organic waste in waste water;

[0021] a chemical adsorption system for removing metal ions and / or toxic chemicals in waste water;

[0022] The pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system are uniformly added with the waste concrete adsorbent.

[0023] In a fifth aspect, the application provides a waste water treatment device used in the waste water treatment system, comprising sequentially connected pretreatment unit, physical precipitation unit, physical adsorption unit and chemical adsorption unit; wherein,

[0024] The pretreatment unit is used for removing solid waste in waste water;

[0025] The physical precipitation unit is used for removing suspended matter in waste water;

[0026] The physical adsorption unit is used for removing organic waste in waste water;

[0027] The chemical adsorption unit is used for removing metal ions and / or toxic chemicals in waste water.

[0028] The waste concrete adsorbent provided by the first aspect of the application is used to crush and clean the waste concrete, remove the soil, oil stains, plants and other impurities on the surface of the concrete. Then, the concrete is crushed to refine the particle size, which helps to improve the subsequent impurity removal and activation effect. The acid impurity removal and activation treatment of the concrete powder further removes the cement residues, metal pollutants, chlorides, sulfates, microbial pollutants and other impurity components in the waste concrete, removes the chemical impurities in the waste concrete itself, and activates the surface of the waste concrete to enhance its adsorption capacity. The calcination treatment of the activated concrete powder improves the chemical activity of the surface of the concrete powder, generates new active sites, improves the surface hydrophilicity, improves the microstructure of the concrete powder, increases the porosity and microcracks of the concrete powder, and promotes the adsorption and exchange of heavy metal ions.

[0029] The waste concrete adsorbent prepared by the above method has a large surface area and rich pore structure, and thus has strong physical adsorption capacity, which can adsorb and remove suspended solids, oil stains, organic pollutants and heavy metal ions and other substances in wastewater. It can also remove suspended solids 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 wastewater, especially ion exchange reaction with some heavy metal ions, to remove them from wastewater.

[0030] The waste concrete adsorbent is used for wastewater treatment. The waste concrete adsorbent is used to pretreat the wastewater to remove solid waste and other impurities. Then, the waste concrete adsorbent and a flocculating agent are used to physically precipitate the pretreated wastewater to remove suspended solids and other impurities. The waste concrete adsorbent and a physical adsorbent are used to physically adsorb the precipitated wastewater to remove organic waste and other impurities. The waste concrete adsorbent and a chemical adsorbent are used to chemically adsorb the adsorbed wastewater to remove heavy metal ions, toxic chemicals and other impurities. The waste concrete adsorbent is used to pretreat, physically precipitate, physically adsorb, chemically adsorb and disinfect the wastewater in sequence, which can remove impurities in the wastewater and convert the wastewater into qualified water for normal use. The waste concrete is recycled and introduced into the water treatment field.

[0031] The wastewater treatment system provided by the application comprises a pretreatment system, a physical precipitation system, a physical adsorption system and a chemical adsorption system which are sequentially connected, and the above-mentioned waste concrete adsorbent is uniformly added in the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system. The waste concrete adsorbent sequentially removes solid waste in the pretreatment system, suspended matter in the physical precipitation system, organic waste in the physical adsorption system, and metal ions and / or toxic chemicals in the chemical adsorption system. The resource utilization of waste concrete is realized, the waste concrete is introduced into the field of water treatment, and the intelligent system is used for monitoring and controlling the adsorption process, so that the working efficiency is improved and the large-scale utilization of waste concrete is realized.

[0032] The wastewater treatment device provided by the application is suitable for the above-mentioned wastewater treatment system, and comprises a pretreatment unit, a physical precipitation unit, a physical adsorption unit and a chemical adsorption unit which are sequentially connected. The impurities in the wastewater can be fully removed through the units, so that the wastewater can be recycled and utilized. BRIEF DESCRIPTION OF DRAWINGS

[0033] In order to more clearly illustrate the technical solutions in the embodiments of the application, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0034] Figure 1 is a flowchart of the preparation method of the waste concrete adsorbent provided by the embodiments of the application;

[0035] Figure 2 is a flowchart of the wastewater treatment method provided by the embodiments of the application;

[0036] Figure 3 is a schematic diagram of the wastewater treatment system provided by the embodiments of the application;

[0037] Figure 4 is a schematic diagram of the pretreatment system in the wastewater treatment system provided by the embodiments of the application;

[0038] Figure 5 is a schematic diagram of the physical precipitation system in the wastewater treatment system provided by the embodiments of the application;

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

[0040] Figure 7 is a schematic diagram of the chemical adsorption system in the wastewater treatment system provided by the embodiments of the application. DETAILED DESCRIPTION

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

[0042] In the present application, the term "and / or" describes the association relationship of the associated objects, which means that there can be three kinds of relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. Wherein A and B can be singular or plural. The character " / " generally represents an "or" relationship between the associated objects before and after it.

[0043] In the present application, "at least one" means one or more, and "multiple" means two or more. "At least one of the following" or similar expressions means any combination of these items, including any combination of single item or multiple items. For example, "at least one of a, b or c", or "at least one of a, b and c", can mean a, b, c, a-b (i.e. a and b), a-c, b-c, or a-b-c, wherein a, b and c can be single or multiple.

[0044] It should be understood that in various embodiments of the present application, the size of the sequence number of the above-mentioned processes does not mean the order of execution, and part or all of the steps can be executed in parallel or in sequence. The execution order of each process should be determined according to its function and inherent 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" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise.

[0046] The weight of the related components mentioned in the embodiments of the present application can not only refer to the specific content of each component, but also represent the weight ratio relationship between each component. Therefore, as long as the content of the related components in the embodiments of the present application is enlarged or reduced in proportion, it is within the scope disclosed in the embodiments of the present application. Specifically, the mass mentioned in the embodiments of the present application can be μg, mg, g, kg and other mass units commonly known in the chemical field.

[0047] The terms "first", "second", "third", etc. are used only for the purpose of description, to distinguish between objects, such as substances, from each other, and cannot be understood as indicating or implying relative importance or implying the number of the indicated technical features. For example, without departing from the scope of the embodiments of the present application, the first XX can also be referred to as the second XX, and similarly, the second XX can also be referred to as the first XX. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features.

[0048] The first aspect of the embodiments of the present application provides a preparation method of a waste concrete adsorbent, as shown in the accompanying drawings, comprising the following steps: Figure 1 The first aspect of the embodiments of the present application provides a preparation method of a waste concrete adsorbent, as shown in the accompanying drawings, comprising the following steps:

[0049] S10. Obtain waste concrete, and after crushing and cleaning treatment, crush to obtain concrete powder;

[0050] S20. Perform acid impurity removal and activation treatment on the concrete powder to obtain activated concrete powder;

[0051] S30. Perform calcination treatment on the activated concrete powder, and crush to obtain a waste concrete adsorbent.

[0052] The waste concrete adsorbent provided by the first aspect of the embodiments of the present application removes the soil, oil stains, plants and other impurities on the surface of the waste concrete through crushing and cleaning treatment. Then, the particle size is refined through crushing treatment, which helps to improve the subsequent impurity removal and activation effect. Through acid impurity removal and activation treatment on the concrete powder, impurity components such as cement residues, metal pollutants, chlorides, sulfates, microbial pollutants and other impurities in the waste concrete are further removed, the chemical impurities of the waste concrete itself are removed, the surface of the waste concrete is acid-activated, and the adsorption capacity is enhanced. Through calcination treatment on the activated concrete powder, the surface chemical activity 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 micro-cracks of the concrete powder are improved, and the adsorption and exchange of heavy metal ions are promoted.

[0053] Therefore, the waste concrete has a large surface area and more pore structure after being prepared into the waste concrete adsorbent by the preparation method of the present application, which makes it have a strong physical adsorption capacity. Thus, the waste concrete adsorbent can remove substances such as suspended solids, oil stains, organic pollutants and heavy metal ions in wastewater through surface adsorption. The waste concrete adsorbent can gather small particles in wastewater through flocculation to form larger particles (flocs), which are convenient for settling or filtering out, so as to remove suspended solids and part of organic matter in wastewater. In addition, the waste concrete adsorbent contains a certain amount of calcium compounds and other components, which have a certain chemical reactivity and can react with some pollutants in wastewater, especially ion exchange reaction with some heavy metal ions (such as lead, copper, cadmium, etc.), so as to remove them from wastewater. For example, calcium ions can combine with heavy metal ions in water to form insoluble hydroxides or carbonates, thereby being removed. In addition, the waste concrete adsorbent as a wastewater treatment material has a certain environmental protection property, because it is a reuse of waste, and by using waste concrete powder for wastewater treatment, the waste storage and environmental burden can be reduced.

[0054] The above step S10: the collected waste concrete is added into a crusher, and after being crushed, it is sent into a concrete washer; the crushed concrete is washed to remove surface soil, oil stains, plants and other impurities. Then the crushed and washed concrete is crushed again and sieved to obtain concrete powder.

[0055] In some possible implementations, after the crushing and washing treatment, 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, etc. typical but non-limiting point value or interval value between any two point values. In this case, it is convenient to wash, and the waste concrete is easy to be lost in the crushing process if the crushing is too small.

[0056] In some possible implementations, the average particle size of the concrete powder is greater than 0 and not higher than 0.5 mm; for example, the average particle size of the concrete powder can be 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, etc. typical but non-limiting point value or 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, aluminosilicate, etc.), metal pollutants, chlorides, sulfates, microbial pollutants, etc. may be left in the waste concrete, which will affect the treatment effect of the concrete on wastewater.

[0058] The step S20: the concrete powder is added into the acid impurity removal solution to remove the chemical impurities such as cement components, metal contaminants, chlorides, sulfates, and microbial contaminants in the waste concrete, and to acid-activate the surface of the waste concrete to enhance the adsorption capacity thereof.

[0059] In some possible implementation manners, the step of acid impurity removal and activation treatment includes mixing the concrete powder with an acid solution with a concentration of 5 mol / L to 7 mol / L. For example, the acid solution can be 5 mol / L, 6 mol / L, 7 mol / L, or any interval value between any two of the above typical but non-limiting point values. In this case, the impurity components can be effectively removed, the adsorption capacity of the concrete powder can be activated, and the structure of the concrete can not be excessively damaged.

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

[0061] The embodiments of the present application can effectively remove the organic matters, dust, and dirt on the surface of the waste concrete by acid impurity removal and activation treatment. The organic matters can occupy the adsorption sites on the surface of the concrete and interfere with the adsorption. By acid washing, the surface can be cleaned, and more active sites can be exposed, thereby providing a larger surface area for the subsequent adsorption process. On the other hand, the acid solution reacts with the waste concrete to corrode the surface of the concrete and form more pores or micro-cracks on the surface of the concrete. These small pores provide more adsorption space for the pollutants (such as heavy metal ions and suspended solids) in the wastewater, thereby enhancing the adsorption capacity. This effect is not only a physical increase in the pores, but also can be accompanied by an increase in the specific surface area, so that the adsorption capacity of the waste concrete is greatly improved. On the other hand, acid activation can also change the chemical properties of the surface of the waste concrete. The main component contained in the concrete is calcium compounds (such as CaO, Ca(OH)2, CaCO3, etc.). When the concrete reacts with the acid, the acid solution can react with these calcium compounds to form soluble salts (such as calcium chloride and calcium sulfate) or hydration products, and more calcium oxide and calcium ions can be exposed. These calcium ions have strong hydrophilicity and can adsorb certain heavy metal ions (such as Pb 2+ , Cd 2+ , Cu 2+ , etc.) in the wastewater through ion exchange. In addition, after acid activation, the hydroxyl ions (OH -) The concentration can 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 acid solution reacts with calcium salt in the concrete, it can cause more hydroxyl (OH - ) or oxygen ions (O 2- ) to be dissociated from the surface, so that the surface of the concrete carries negative charges. For some positively charged pollutants in wastewater (such as certain metal ions), the surface of the acid-activated concrete can enhance the adsorption capacity of these ions through electrostatic attraction.

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

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

[0064] The application embodiment calcines the activated concrete powder. Under high temperature conditions, the microstructure of the waste concrete will change. High temperature can promote the opening of the internal micropores and cracks of 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 can cause the generation of microcracks on the surface of the concrete, which can become more adsorption sites for pollutants, further enhancing its adsorption capacity. The hydration products in the waste concrete (such as calcium hydroxide, calcium silicate hydrate, etc.) will undergo a transformation process under high temperature, resulting in changes in their structure and properties: high temperature can cause some hydration products in the concrete (such as calcium hydroxide) to dehydrate, forming more stable calcium oxide (CaO). Calcium oxide has strong hydrophilicity and chemical reactivity, and can react with some pollutants in wastewater, especially adsorbing heavy metal ions or ion exchanging with pollutants in water. Silicate hydrates may undergo some structural rearrangement under high temperature, making them more porous and more chemically reactive, thereby enhancing the adsorption capacity of the concrete. In addition, high temperature will cause changes in the chemical activity of the concrete surface, which is specifically manifested as: under high temperature, some chemical bonds on the surface of the concrete may be broken, 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+ , etc.). After high temperature treatment, the surface hydrophilicity of the concrete may be improved, allowing it to better adsorb ions and organic pollutants dissolved in water.

[0065] For example, the calcination treatment is carried out under an inert atmosphere of nitrogen, argon, helium, etc. The heating rate can be 10℃ / h, 12℃ / h, 15℃ / h, 18℃ / h, 20℃ / h, etc. typical but non-limiting arbitrary point value or interval value between any two point values, the holding temperature can be 300℃, 320℃, 350℃, 380℃, 400℃, etc. typical but non-limiting arbitrary point value or interval value 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 value or interval value 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 0.01 mm, 0.02 mm, 0.03 mm, 0.05 mm, 0.06 mm, 0.08 mm, 0.1 mm, or any interval value between any two point values, for example.

[0067] In a second aspect, the embodiments of the present application provide a waste concrete adsorbent, which is prepared by the method described above.

[0068] The waste concrete adsorbent prepared by the method described above has a large surface area and rich pore structure, and thus has strong physical adsorption capacity, and can adsorb and remove suspended solids, oil stains, organic pollutants, heavy metal ions and other substances in wastewater. It can also remove suspended solids 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 wastewater, especially ion exchange reaction with some heavy metal ions, to remove them from wastewater.

[0069] In a third aspect, the embodiments of the present application provide a wastewater treatment method, as shown in FIG. 2. Figure 2 The method comprises the following steps:

[0070] S40. Pre-treating the wastewater by using the waste concrete adsorbent to obtain pre-treated wastewater;

[0071] S50. Physically precipitating the pre-treated wastewater by using the waste concrete adsorbent and a flocculant to obtain precipitated wastewater;

[0072] S60. Physically adsorbing the precipitated wastewater by using the waste concrete adsorbent and a physical adsorbent to obtain adsorbed wastewater;

[0073] S70. Chemically adsorbing the adsorbed wastewater by using the waste concrete adsorbent and a chemical adsorbent, disinfecting and detecting to obtain qualified water.

[0074] The embodiment of the present application uses the above-mentioned waste concrete adsorbent to treat wastewater. The waste concrete adsorbent is used to pretreat the wastewater to remove solid waste and other impurities. Then the waste concrete adsorbent and flocculants are used to physically precipitate the pretreated wastewater to remove suspended solids and other impurities in the wastewater. The waste concrete adsorbent and physical adsorbents are used to physically adsorb the precipitated wastewater to adsorb and remove organic waste and other impurities in the wastewater. The waste concrete adsorbent and chemical adsorbents are used to chemically adsorb the adsorbed wastewater to adsorb and remove heavy metal ions, toxic chemicals and other impurities in the wastewater. After the above-mentioned waste concrete adsorbent is used to pretreat, physically precipitate, physically adsorb, chemically adsorb and disinfect the wastewater in sequence, the impurities in the wastewater can be removed, and the wastewater can be converted into qualified water that can be normally used. The resource utilization of waste concrete is realized, and the waste concrete is introduced into the field of water treatment.

[0075] The above-mentioned step S40: the waste concrete adsorbent is used to pretreat the wastewater. In this process, the waste concrete adsorbent is directly added to the wastewater to promote the precipitation of solid waste. Then filtration treatment is performed to filter the larger solid impurities to obtain pretreated wastewater.

[0076] In some possible implementations, the mass ratio of the waste concrete adsorbent to the wastewater is 1:(8-12). For example, the mass ratio of the waste concrete adsorbent to the wastewater can be 1:8, 1:9, 1:10, 1:11, 1:12 or any interval value between any two point values. In this case, the solid waste in the wastewater can be sufficiently removed.

[0077] The above-mentioned step S50: the waste concrete adsorbent and flocculants are used to physically precipitate the pretreated wastewater to remove suspended solids in the wastewater by flocculation.

[0078] In some possible implementations, the mass ratio of the waste concrete adsorbent to the flocculants is (1-3):1, and can be 1:1, 1:2, 1:3 or any 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, the amount of sediment in the water may be too much, thereby increasing the burden of subsequent treatment processes (such as sedimentation and filtration). Too high a concentration of the waste concrete adsorbent may cause the resuspension of part of the sediment or block the filtration system. In addition, if the proportion of the waste concrete adsorbent is too low, the removal effect of larger particles in the wastewater may be poor, especially the removal effect of some coarse particles and sediment. Too much flocculant may cause excessive flocculant residues, thereby affecting the water quality and requiring additional post-treatment.

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

[0080] In some embodiments, after the physical precipitation treatment, a filtration treatment is performed, the filter residue is subjected to a filter pressing treatment, and after being dried by heating, the filter residue can be used as a raw material for recycled concrete.

[0081] The above step S60: The waste concrete adsorbent and the physical adsorbent are used to perform a physical adsorption treatment on the precipitated wastewater, and impurity components such as organic waste in the wastewater are adsorbed and removed.

[0082] In some possible implementations, the mass ratio of the waste concrete adsorbent to the physical adsorbent is (1-2):1; specifically, it can be 1:1, 1:2, or the like. In this case, the organic pollutants of large and small particles in the wastewater can be fully adsorbed and removed. If the proportion of the physical adsorbent is too low, the removal effect of fine organic pollutants (such as dissolved organic matter and dyes) may be poor. If the proportion of the waste concrete adsorbent is too high, too much precipitate may be generated, which affects the subsequent treatment (such as sedimentation and filtration) of the wastewater. If the proportion of the waste concrete adsorbent is too low, large-particle substances cannot be removed, and the suspended solids and large particles in the wastewater may not be effectively removed, which affects 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 a high specific surface area and strong adsorption capacity for organic pollutants in the 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 specifically, it can be 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, or the like, or an interval value between any two point values, which can ensure good adsorption effect and provide appropriate fluidity.

[0085] In some embodiments, after the physical adsorption treatment, a filtration treatment is performed, the organic matter in the treated water is detected, and if it is qualified, the water enters the next treatment link, and if it is unqualified, the water is subjected to physical adsorption treatment again. The filter residue is subjected to a filter pressing treatment, and after being dried by heating, the filter residue can be used as a raw material for recycled concrete.

[0086] The step S70 is to perform chemical adsorption treatment on the adsorbed wastewater by using the waste concrete adsorbent and the chemical adsorbent. The chemical adsorption and reaction help the aggregation and settlement of heavy metal ions (Pb 2+ , Cr 3+ , Cd 2+ , Cu 2+ , Zn 2+ , As 3+ and other particles. Subsequently, filtration treatment is performed, and the insoluble precipitates are filtered, and the insoluble precipitates are filtered by 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 and the chemical adsorbent is 3:(1-3), and can be 3:1, 3:2, 3:3, or any interval value between any two point values of the typical but non-limiting point values. In this case, the adsorption and removal of heavy metal ions and toxic chemicals in the wastewater can be sufficiently ensured.

[0088] In some possible implementations, the chemical adsorbent includes iron salts and aluminum salts with a mass ratio of (2-4):1. For example, the mass ratio of the iron salts and the aluminum salts can be 2:1, 3:1, 4:1, or any interval value between any two point values of the typical but non-limiting point values. In this case, the adsorption and removal of heavy metal ions and toxic chemicals in the wastewater can be sufficiently ensured. Too high a proportion of iron salts can cause excessive precipitates to be generated, which not only increases the amount of solid waste in the wastewater, but also can cause a burden on subsequent filtration and dewatering processes. Too high a proportion of aluminum salts can cause excessive aluminum hydroxide precipitates to be generated, which affects the clarification effect of the water and can cause the residual aluminum concentration to increase in subsequent treatment, which adversely affects the environment. By controlling the proportion of the waste concrete adsorbent, the iron salts, and the aluminum salts, the adsorption and removal of impurity components in the wastewater can be ensured, and additional impurity components can be avoided.

[0089] In some embodiments, the iron salts include ferric chloride, ferrous sulfate, and the like; and the aluminum salts include polyaluminum chloride, aluminum sulfate, and the like.

[0090] In some embodiments, the waste concrete sorbent typically contains abundant mineral components, particularly silicates and calcium compounds in cement. These components impart good physical adsorption properties to the concrete, especially in removing particulate matter, suspended solids, and partially dissolved heavy metal ions. The concrete sorbent interacts with particulate matter and dissolved heavy metal ions in the wastewater through surface adsorption. These substances can be fixed on the surface of the concrete sorbent through van der Waals forces, hydrogen bonds, and other physical adsorption forces. The calcium ions in the concrete can undergo ion exchange reactions with certain metal ions in the wastewater, removing heavy metal ions such as lead, copper, cadmium, and others. The porous structure of the concrete surface provides a large surface area, which enables it to effectively capture particulate matter and pollutants in water, reducing the concentration of solid suspended solids. Iron salts play a crucial role as flocculants and precipitants in wastewater treatment, especially in removing dissolved metal ions and particulate matter from water. Iron salts (such as ferric sulfate, ferric chloride) release trivalent iron ions upon dissolution, which combine with suspended particles or organic matter in water to form larger flocs. The formation of flocs helps to increase the settling velocity of particulate matter, facilitating removal by sedimentation or filtration. Iron salts can also undergo precipitation reactions with heavy metal ions (such as lead, copper, zinc, etc.) in water, forming insoluble metal hydroxides or iron metal complexes, thereby effectively removing these harmful substances. For example, Fe 3+ reacts with Pb 2+ to form a precipitated iron-lead complex. Iron salts (especially divalent iron) also have reducing properties, which can reduce certain heavy metal ions (such as hexavalent chromium) to less toxic or insoluble trivalent metals, thereby reducing their toxicity. Aluminum salts (such as alum, aluminum sulfate) work by primarily removing heavy metals and particulate matter from wastewater through flocculation and precipitation reactions. Aluminum salts release Al 3+ ions upon dissolution, which can combine with suspended particulate matter in water to form larger flocs. These flocs are more easily removed by sedimentation or filtration. Aluminum salts are particularly effective in removing organic and inorganic particulate matter from 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+ to form a lead hydroxide precipitate that effectively removes lead from water. Aluminum salts can also adjust the pH of the water body through neutralization, optimizing the effectiveness of subsequent treatment.

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

[0092] In some embodiments, after chemical adsorption treatment, filtration treatment is performed, and the content of heavy metal ions, the content of toxic chemicals, etc. in the treated water are detected respectively. The water that passes the detection enters the next treatment link, and the water that fails the detection is subjected to chemical adsorption treatment again. The filter residue is subjected to pressure filtration treatment, and after heating and drying, it can be used as a raw material for recycled concrete.

[0093] In some possible implementations, chlorine disinfection is used for disinfection. Bacteria, viruses and other pathogenic microorganisms in the wastewater are killed to ensure the safety of the treated water and prevent the spread of diseases.

[0094] In some possible implementations, water quality detection is performed, and after passing the detection, qualified water, i.e., normal water, is obtained. The chemical oxygen demand in the qualified water is <15 mg / L; the suspended solids are <25 mg / L; the chlorides are <250 mg / L; the total dissolved solids are <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 the qualified water is <15 mg / L, the suspended solids (SS, mainly detecting the content of solid particulate matter) are <25 mg / L, the chlorides (Cl - ) are <250 mg / L, the total dissolved solids (TDS) are <1000 mg / L, the heavy metal ions are: lead (Pb 2+ ): ≤0.01 mg / L, mercury (Hg 2+ ): ≤0.0005 mg / L, cadmium (Cd 2+ ): ≤0.005 mg / L, copper (Cu 2+ ): ≤1.0 mg / L, zinc (Zn 2+ ): ≤1.0 mg / L, iron (Fe 2+ / Fe 3+ ): ≤1.0 mg / L, nickel (Ni 2 + ): ≤0.05 mg / L, chromium (Cr3+ / Cr 6+ ) : <0.05 mg / L, cobalt (Co 2+ ) : <0.05 mg / L, antimony (Sb 3+ ) : <0.005 mg / L, arsenic (As 3+ / As 5+ ) : <0.05 mg / L.

[0096] In a fourth aspect, the embodiments of the present application provide a wastewater treatment system, as shown in the accompanying drawings, comprising, in sequence: Figure 3 a pretreatment system for removing solid waste in wastewater;

[0097] a physical precipitation system for removing suspended solids in wastewater;

[0098] a physical adsorption system for removing organic waste in wastewater;

[0099] a chemical adsorption system for removing metal ions and / or toxic chemicals in wastewater;

[0100] wherein the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system are uniformly added with the above-mentioned waste concrete adsorbent.

[0101] The wastewater treatment system of the embodiments of the present application comprises, in sequence, a pretreatment system, a physical precipitation system, a physical adsorption system and a chemical adsorption system, and the pretreatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system are uniformly added with the above-mentioned waste concrete adsorbent. The above-mentioned waste concrete adsorbent is used to sequentially remove solid waste in the pretreatment system, suspended solids in the physical precipitation system, organic waste in the physical adsorption system, and metal ions and / or toxic chemicals in the chemical adsorption system. The resource utilization of waste concrete is realized, the waste concrete is introduced into the field of water treatment, and the adsorption process is monitored and controlled through an intelligent system, thereby improving the work efficiency and realizing the large-scale utilization of waste concrete.

[0102] In some embodiments, the pretreatment system is as shown in the accompanying drawings, and the wastewater is first introduced into a screen to remove larger solid particles such as plastic, wood chips, leaves, sand, etc., and then flows into a grit chamber to make the heavier particles (such as sand, soil, etc.) settle to the bottom of the chamber by changing the flow velocity of the water. In this process, the waste concrete adsorbent is directly added to the water to promote the precipitation of solid waste. Subsequently, a filtration treatment is performed to filter out larger solid impurities.

[0103] Figure 4

[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, which can damage the screen with the solid waste. For a relatively coarse screen (e.g., with a pore size of 1-3 mm), the flow rate should generally not exceed 1-2 m / s. For a relatively fine screen (e.g., with a pore size of about 0.2 mm), the flow rate should be controlled to be within 0.5 m / s to avoid excessive pressure on the screen, especially when there is a large amount of suspended solids or solid particles in the wastewater.

[0105] In some embodiments, the pretreatment system needs to monitor the flow rate of the wastewater into the grit chamber to prevent the flow rate from being too fast, which can affect the settling of the solid waste. For the flow rate of the wastewater into the grit chamber, the flow rate should preferably be controlled to be between 0.3-0.5 m / s to ensure the settling effect. Specifically, the flow rate can be taken as 0.3 m / s.

[0106] In some embodiments, the pretreatment system needs to monitor the flow rate of the wastewater through the filter press to prevent the flow rate from being too fast, which can damage the filter press with the solid waste. Generally, the feed flow rate should not exceed 2-3 m / s, and appropriate adjustments can be made according to the specific wastewater conditions and the specifications of the filter press. Specifically, the flow rate can be taken as 2 m / s.

[0107] In some embodiments, the pretreatment system needs to monitor the quality of the product in the screen and the filter press, and after reaching the set point, the container is opened to automatically collect the leaching concrete aggregate therein to prevent the product from being too much to block the wet screen and the filter press, which can affect the subsequent filtration. Appropriate adjustments can be made according to the specific wastewater conditions and the specifications of the filter press and the screen, as long as the screen and the filter press are not blocked. When the system detects that the product is too much to block the screen and the filter press, the pumping of the wastewater into the grit chamber is stopped. After the system detects that the blockage is removed, the system automatically restarts the subsequent steps.

[0108] In some possible implementations, the physical sedimentation system is further added with at least one flocculant selected from the group consisting of alum, aluminum sulfate, and polyaluminum chloride; and cooperates with the waste concrete adsorbent to better remove the suspended solids in the wastewater.

[0109] In some embodiments, the physical sedimentation is as shown in FIG. 2B. Figure 5 As shown in FIG. 2B, after the pretreatment, the wastewater is pumped into the physical sedimentation tank, and in this stage, most of the suspended solids in the wastewater are removed by natural sedimentation. The solid particles (e.g., silt, suspended solids) in the wastewater are settled to the bottom of the tank due to the action of gravity. This step can remove most of the suspended solids and some heavier particulate pollutants. In this process, the concrete adsorbent is mixed with a flocculant (e.g., alum, aluminum sulfate, polyaluminum chloride) at a ratio of (1-3): 1 to promote the flocculation of the suspended solids and particulate matter, accelerate the sedimentation, and improve the removal efficiency. Subsequently, a filtration treatment is performed to filter the flocculation, and the flocculation is filtered through a filter press, and then dried by heating to obtain a recycled concrete preparation raw material.

[0110] In some embodiments, the flow rate of wastewater entering the physical sedimentation tank in the physical sedimentation system is monitored to prevent excessively high flow rates from affecting flocculant settling. The flow rate of wastewater passing through the filter press in the physical sedimentation system is also monitored to prevent excessively high flow rates that could damage the filter press due to rapid flocculant velocity. The mass of the product in the filter press in the physical sedimentation system is monitored; once a set point is reached, the container is opened to automatically collect the sediment, preventing excessive sediment from clogging the filter press and affecting subsequent filtration. When the system detects excessive product clogging the filter press, wastewater pumping is stopped. After the system detects that the blockage has been cleared, it automatically restarts to proceed with subsequent steps.

[0111] In some possible implementations, the physical adsorption system also includes at least one physical adsorbent selected from activated carbon, natural zeolite, charcoal, and activated silica; in conjunction with waste concrete adsorbent, it removes organic waste from wastewater.

[0112] In some embodiments, the physical adsorption system is as follows: Figure 6 As shown, after physical sedimentation, the wastewater flows into a physical adsorption tank, where organic matter and some heavy metal ions are adsorbed. In this process, concrete adsorbent is mixed with physical adsorbents such as activated carbon, natural zeolite, charcoal, and activated silica in a ratio of (1-2):1 and added to the system to improve the adsorption rate and removal efficiency. Subsequently, filtration is performed to remove the solid precipitate. The solid precipitate is then filtered through a filter press and subsequently heated and dried to obtain raw materials for recycled concrete preparation.

[0113] In some embodiments, the flow rate of wastewater entering the physical sedimentation tank in the physical adsorption system is monitored to prevent excessive flow rate from affecting the solid sedimentation rate. The flow rate of wastewater passing through the filter press in the physical adsorption system is also monitored to prevent excessive flow rate and rapid solid sedimentation from damaging the filter press. The mass of the product in the filter press in the physical adsorption system is monitored; after reaching a set point, the container is opened to automatically collect the sediment, preventing excessive sedimentation from clogging the filter press and affecting subsequent filtration. When the system detects excessive product clogging the filter press, wastewater pumping is stopped. After the system detects that the blockage has been cleared, the system automatically restarts to proceed with subsequent steps. The concentration of organic matter in the wastewater passing through the filter press is monitored; if the concentration does not meet the requirements, the wastewater is reintroduced into the physical adsorption tank for physical adsorption.

[0114] In some possible implementations, iron and aluminum salts in a mass ratio of (2–4):1 are also added to the chemisorption system. This works synergistically with waste concrete adsorbents to remove metal ions and / or toxic chemicals from wastewater.

[0115] In some embodiments, the chemical adsorption system is as follows: Figure 7As shown, after physical adsorption, the wastewater flows into the chemical adsorption tank, 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 aggregation and sedimentation of heavy metal ions (Pb 2+ , Cr 3+ , Cd 2+ , Cu 2+ , Zn 2 + , As 3+ and other particles. Subsequent filtration treatment removes insoluble precipitates, which are filtered through a filter press, followed by heating and drying to obtain recycled concrete raw materials.

[0116] In some embodiments, the flow rate of wastewater into the physical precipitation tank in the chemical adsorption system is monitored to prevent the flow rate from being too fast to affect the precipitation rate of insoluble precipitates. The flow rate of wastewater through the filter press in the chemical adsorption system is monitored to prevent the flow rate from being too fast, causing the insoluble precipitates to damage the filter press at too high a speed. The product quality in the filter press in the chemical adsorption system is monitored, and after reaching the set point, the container is opened to automatically collect the precipitates, preventing the precipitates from clogging the filter press and affecting subsequent filtration. When the system detects that the product is clogging the filter press, the pumping of wastewater is stopped. After the system detects that the clogging is removed, the system automatically restarts for subsequent steps. The concentration of heavy metal ions in the wastewater passing through the filter press is monitored, and when the concentration does not meet the requirements, the wastewater is re-directed to the physical adsorption tank for physical adsorption.

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

[0118] In a fifth aspect, the embodiments of the present application provide a wastewater treatment device used by the wastewater treatment system described above, 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 the wastewater;

[0120] The physical precipitation unit is used to remove suspended solids from the wastewater;

[0121] The physical adsorption unit is used to remove organic waste from the wastewater;

[0122] The chemical adsorption unit is used for removing metal ions and / or toxic chemicals in the wastewater.

[0123] The wastewater treatment device of the embodiment of the present application is suitable for the wastewater treatment system, and comprises a pretreatment unit, a physical sedimentation unit, a physical adsorption unit and a chemical adsorption unit which are sequentially communicated. Impurity components in the wastewater can be fully removed through the units, so that the wastewater can be recycled and utilized.

[0124] In order to make the above-mentioned implementation details and operations of the present application be clearly understood by those skilled in the art, and the further performance of the waste concrete adsorbent and the preparation method thereof, the wastewater treatment system and the device is significantly embodied, the following will be illustrated by multiple embodiments.

[0125] Embodiment 1

[0126] A waste concrete adsorbent, as shown in the accompanying drawings, is prepared by the following steps: Figure 1

[0127] The waste concrete 2 kg is crushed to pass through a sieve with a pore diameter of 1 mm, and then soaked and filtered in water for 6 h. Then the concrete is crushed again and passed through a sieve with a pore diameter of 0.5 mm. Then the concrete is soaked in a 0.1 mol / L dilute hydrochloric acid solution for 6 h for acid activation, and the powder is filtered and then dried in a dryer. The temperature is raised to 300°C at a speed of 10°C / h under a nitrogen atmosphere, and the drying is performed for 24 h. Then the concrete is crushed in a ball mill and passed through a sieve with a pore diameter of 0.1 mm to obtain the waste concrete adsorbent.

[0128] A method for treating wastewater by using a waste concrete adsorbent, as shown in the accompanying drawings, uses a wastewater treatment system as shown in the accompanying drawings, and comprises the following steps: Figure 2 Figure 3

[0129] 1. Pretreatment: The wastewater is first filtered into a sieve at a flow rate of 0.5 m / s, and then flows into a grit chamber to make the heavier particles precipitate, and then is filtered.

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

[0131] ​​​3. Physical adsorption treatment: After the physical precipitation treatment, the wastewater is flowed into the physical adsorption tank at a speed of 0.5 m / s. In this process, 500 g of concrete adsorbent is mixed with 500 g of activated carbon at a ratio of 1:1, and is added into the tank. After 3 h of precipitation, a filtration treatment is performed, and the solid precipitate is filtered through a filter press. The filter residue is then dried by heating, and can be used as a raw material for the preparation of recycled concrete.

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

[0133] 5. After the chemical adsorption treatment, it is found that the oxygen content and the concentration of suspended solids and heavy metal ions in the water are qualified and meet the requirements.

[0134] Example 2

[0135] A waste concrete adsorbent, as shown in FIG. 2, is prepared by the following steps: Figure 1

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

[0137] A method for treating wastewater using a waste concrete adsorbent, as shown in FIG. 3, uses a wastewater treatment system as shown in FIG. 2, and includes the following steps: Figure 2 Figure 3

[0138] 1. Pretreatment: The wastewater is first filtered through a screen at a flow rate of 0.5 m / s, and then flowed into a grit chamber to precipitate heavier particles, and then filtered.

[0139] ​​​2. Physical Sedimentation Treatment: After pretreatment, the wastewater is pumped into a physical sedimentation tank at a speed of 1 m / s. Solid particles (such as silt and suspended solids) in the wastewater settle to the bottom of the tank due to gravity. During this process, 500g of concrete adsorbent and 250g of alum (Al2(SO4)3) are mixed in a 2:1 ratio and added to the sedimentation tank. After sedimentation for 4 hours, filtration is performed to remove the flocculent material. The flocculent material is then filtered through a filter press. The filter residue is subsequently heated and dried, and can be used as a raw material for the preparation of recycled concrete.

[0140] 3. Physical Adsorption Treatment: After physical sedimentation, the wastewater flows into the physical adsorption tank at a rate of 1 m / s. During this process, 500 g of concrete adsorbent and 500 g of zeolite are mixed in a 1:1 ratio and added to the tank. After sedimentation for 3 hours, filtration is performed to remove the solid precipitate. The solid precipitate is then filtered through a filter press. The filter residue is subsequently heated and dried, and can be used as a raw material for the preparation of recycled concrete.

[0141] 4. Chemical Adsorption Treatment: After physical adsorption treatment, the wastewater flows into the chemical adsorption tank at a rate of 1 m / s. During this process, 600 g of concrete adsorbent is mixed with 200 g of ferric chloride (FeCl3) and 200 g of polyaluminum chloride (Al2(OH)6Cl3) in a 3:1:1 ratio and added to the sedimentation tank. After sedimentation for 1 hour, filtration is performed to remove insoluble precipitates. The insoluble precipitates are then filtered through a filter press. The filter residue is subsequently heated and dried, and can be used as a raw material for the preparation of recycled concrete.

[0142] 5. After chemical adsorption treatment, the oxygen content, suspended solids, and heavy metal ion concentration in the water were all found to be within acceptable limits and met the requirements.

[0143] Example 3

[0144] An adsorbent for waste concrete, as shown in the attached... Figure 1 As shown, its preparation includes the following steps:

[0145] Two kilograms of waste concrete were crushed and passed through a 1-mm sieve, then soaked in water and filtered for 6 hours. The concrete was then crushed again and passed through a 0.5-mm sieve. Next, the concrete was soaked in a 0.1 mol / L dilute hydrochloric acid solution for 6 hours for acid activation. After powder filtration, the powder was placed in a desiccator and dried at 400°C for 24 hours under a nitrogen atmosphere at a rate of 15°C / h. Finally, the concrete was crushed in a ball mill and passed through a 0.1-mm sieve to obtain the waste concrete adsorbent.

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

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

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

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

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

[0151] 5. After chemical adsorption treatment, it is found that the oxygen content and suspended matter, heavy metal ion concentration in the water are qualified and meet the requirements.

[0152] Comparative Example 1

[0153] A wastewater treatment method, comprising the following steps:

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

[0155] 2. The wastewater is then pumped into a physical sedimentation tank at a speed of 0.5 m / s. The solid particles (such as sand, suspended matter) in the wastewater settle to the bottom of the tank due to gravity. In this process, 750 g of alum is added to the sedimentation tank, and after 4 hours of sedimentation, filtration treatment is performed.

[0156] 3. After that, the wastewater flows into the physical adsorption tank at a speed of 0.5 m / s, in the process, 1000 g of activated carbon is added into the tank, and after 3 h of precipitation, filtration treatment is performed.

[0157] 3. After that, the wastewater flows into the chemical adsorption tank at a speed of 0.5 m / s, in the process, 500 g of ferrous sulfate (FeSO4) and 500 g of aluminum sulfate (Al2(SO4)3) are mixed in a ratio of 1:1, added into the precipitation tank, and after 1 h of precipitation, filtration treatment is performed.

[0158] 4. After that, it is found that the oxygen content and the suspended matter in the water meet the requirements, and the heavy metal ion concentration is unqualified.

[0159] In order to verify the progressiveness of the embodiments of the present application, the water treated by the above embodiments and the comparative examples is detected, and the detection 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 Solids 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 Lead (Pb 2+ ) mg / L 0 0 0 0.006 Mercury (Hg 2+ ) mg / L 0 0 0 0 Cadmium (Cd 2+ ) mg / L 0 0 0 0.005 Copper (Cu 2+ ) mg / L 0.102 0.253 0.379 1.341 Zinc (Zn 2+ ) mg / L 0.031 0.115 0.192 0.545 Iron (Fe 2+ / Fe 3+ ) mg / L 0.183 0.243 0.423 1.252 Nickel (Ni 2+ ) mg / L 0.011 0.028 0.036 0.054 Chromium (Cr 3+ / Cr 6+ ) mg / L 0.131 0.253 0.325 1.221 Cobalt (Co 2+ ) mg / L 0.021 0.033 0.037 0.063 Sb 3+ ) mg / L 0 0 0 0.004 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 prepared waste concrete adsorbent is used to treat wastewater in the embodiments of the present application, and the oxygen content, suspended matter, and heavy metal ion concentration in the treated water all meet the requirements and can be normally used. In Comparative Example 1, the waste concrete adsorbent is not used to treat wastewater, and the heavy metal ion concentration in the treated water is still high, and the effluent is unqualified.

[0163] The above only describes the preferred embodiments of the present application and does not limit the present application, and any modification, equivalent replacement, and improvement made within the spirit and principle 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 by, The method comprises the following steps: obtaining waste concrete, crushing and cleaning, and then crushing to obtain concrete powder; carrying out acid impurity removal and activation treatment on the concrete powder to obtain activated concrete powder; wherein the acid impurity removal and activation treatment comprises mixing the concrete powder with an acid solution with a concentration of 5-7 mol / L; carrying out calcination treatment on the activated concrete powder at 300-400°C, and crushing to obtain waste concrete adsorbent.

2. The method for preparing the waste concrete adsorbent as described in claim 1, characterized in that, The calcination treatment conditions comprise: heating to 300-400°C at a rate of 10-20°C / h in an inert atmosphere, and maintaining for 12-36 hours.

3. The method of claim 2, wherein the waste concrete sorbent is prepared by the steps of: After the crushing and cleaning treatment, 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 acid solution comprises at least one of hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid.

4. A waste concrete sorbent, characterized by, The waste concrete adsorbent is prepared by the method of any one of claims 1-3.

5. A method of treating wastewater, characterized by, The waste concrete adsorbent is used for wastewater treatment, comprising the following steps: pretreating the wastewater with the waste concrete adsorbent to obtain pretreated wastewater; carrying out physical precipitation treatment on the pretreated wastewater with the waste concrete adsorbent and a flocculant to obtain precipitated wastewater; carrying out physical adsorption treatment on the precipitated wastewater with the waste concrete adsorbent and a physical adsorbent to obtain adsorbed wastewater; carrying out chemical adsorption treatment on the adsorbed wastewater with the waste concrete adsorbent and a chemical adsorbent, disinfecting, and detecting to obtain qualified water.

6. The wastewater treatment method according to claim 5, characterized by, 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 comprises 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 comprises 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 with a mass ratio of (2-4):1; and / or, the disinfection is chlorination disinfection.

7. The wastewater treatment method according to claim 5 or 6, characterized by, The chemical oxygen demand in the qualified water is <15 mg / L; the suspended solids are <25 mg / L; the chlorides are <250 mg / L; the total dissolved solids are <1000 mg / L; and the total amount of heavy metal ions is ≤3.0 mg / L.

8. A wastewater treatment system, characterized by, The method comprises the following steps in sequence: a pretreatment system for removing solid waste from wastewater; a physical precipitation system for removing suspended solids from wastewater; a physical adsorption system for removing organic waste from wastewater; A chemical adsorption system for removing metal ions and / or toxic chemicals in wastewater; The pre-treatment system, the physical precipitation system, the physical adsorption system and the chemical adsorption system are uniformly added with the waste concrete adsorbent according to claim 4.

9. The wastewater treatment system of claim 8, wherein, After the chemical adsorption system, a disinfection system and a water quality detection system are further included, wherein the disinfection system is used for disinfecting the water; And / or, the physical precipitation system is further added with at least one flocculant selected from alum, aluminum sulfate and polyaluminum chloride; And / or, the physical adsorption system is further added with at least one physical adsorbent selected from activated carbon, natural zeolite, charcoal and activated silica; And / or, the chemical adsorption system is further added with iron salt and aluminum salt in a mass ratio of (2-4):1.

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