Method for preparing sewage purifier using oyster shells

Abstract

The present application provides a method for preparing a sewage purifier using oyster shells, comprising the following steps: 1) cleaning, sun-drying, and calcining the oyster shells; 2) placing ferric chloride in a distillation kettle, placing the calcined powder in a condenser, and evacuating the vessel; 3) heating the ferric chloride so that the ferric chloride evaporates and becomes gaseous ferric chloride; 4) in the condenser, the gaseous ferric chloride diffuses into pores in the calcined powder and comes into full contact with the outer surface of the calcined powder; the gaseous ferric chloride is gradually cooled and becomes solid and deposited in the pores and on the outer surface; the CaO calcined at high temperature decomposes into calcium ions and hydroxide ions upon entering water, providing the hydroxide ions and hydroxides required for ferric chloride water purification; the ferric chloride is deposited in the porous medium and on a large specific surface area through evaporation-condensation, thereby increasing the reaction probability, reaction time, and number of reactions between the ferric chloride and the pollutants; the synergistic effect improves the quality and efficiency, thereby improving the effect and efficiency of sewage purification.

Description

Technical Field

[0001] The invention belongs to the technical field of oyster shell recovery, and particularly relates to a method for preparing a sewage purifier by utilizing oyster shells. Background Art

[0002] Oysters are the world's largest aquacultured shellfish and my country's most important marine commercial shellfish. Oyster shells are composed of organic macromolecules such as minerals, proteins, and polysaccharides. The primary inorganic component of oyster shells is calcium carbonate, accounting for over 90% by mass. Organic components such as polysaccharides and proteins account for approximately 3% to 5% of the shell's content.

[0003] Currently, oyster production and processing primarily utilizes the oyster meat, while the inedible shell, which accounts for over 60% of the oyster's mass, is not effectively utilized. Instead, the majority of oyster shells are discarded as solid waste, piling up on mudflats and other areas. Due to their extremely stable physical and chemical properties, the natural decomposition of oyster shells takes a long time, resulting in large accumulations of discarded oyster shells that consume valuable land resources. Furthermore, the residual meat and juice in the discarded shells can spoil, breed mosquitoes and flies, and produce toxic substances and harmful gases, directly and indirectly causing serious pollution to the terrestrial and marine environments.

[0004] Oyster shells are inherently alkaline, reacting with heavy metals in water to produce precipitation. Calcined oyster shells also possess numerous interconnected porous structures, which, through various modification treatments, can enhance their exchange and adsorption capacities. Therefore, oyster shells are used in the treatment of municipal and industrial wastewater, adsorbing harmful components in wastewater. Compared to natural oyster shell powder, calcined oyster shells, due to their greater pore structure and larger specific surface area, are more effective in adsorbing heavy metals and other pollutants from wastewater. Oyster shells calcined at high temperatures possess strong dispersion, adsorption, and exchange capabilities, making them widely used in related fields such as food, medicine, construction, wastewater treatment, and agriculture.

[0005] Therefore, how to realize the resource utilization of oyster shells, increase their added value, and protect the environment is a technical problem that technicians in this field urgently need to solve. Summary of the Invention

[0006] The invention aims to provide a method for preparing a sewage purifying agent by utilizing oyster shells.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for preparing a sewage purifier using oyster shells comprises the following steps performed in sequence:

[0009] 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 30-100 μm, and calcining the oyster shell powder to obtain calcined powder;

[0010] 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump;

[0011] 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride;

[0012] 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder;

[0013] In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After cooling and deposition, the sewage purifier is obtained.

[0014] Preferably, in step 1), the calcination process is specifically as follows: first, heating the oyster shell powder to 240° C.-260° C. and keeping the temperature for 0.5 h-1 h;

[0015] The oyster shell powder is then heated to 750° C.-850° C. and kept warm for 2 h-4 h.

[0016] Preferably, in step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa.

[0017] Preferably, in step 3), the ferric chloride in the distillation kettle is heated to 240° C.-260° C., and the ferric chloride is stirred by a stirring blade installed in the distillation kettle, and the speed of the stirring blade is controlled to be 500-1000 r / min.

[0018] Preferably, in step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40°C-70°C.

[0019] Preferably, in step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 10%-30%.

[0020] This application has achieved the following beneficial technical effects:

[0021] Since the main role of ferric chloride in sewage treatment is the role of the product after its reaction with hydroxide alkalinity as a coagulant and coagulant aid, and the CaO (quicklime) in the oyster shells after high-temperature calcination decomposes into calcium ions and hydroxide ions after entering the water, that is, CaO (quicklime) provides the hydroxide ions and hydroxides required for ferric chloride water purification after entering the water. The hydrolysis of CaO produces exactly what ferric chloride needs. This is the first synergistic cooperation between CaO and ferric chloride in this application to improve quality and efficiency;

[0022] Furthermore, the oyster shells after high-temperature calcination form a complex porous structure, which gives them more pore structures and a larger specific surface area. Ferric chloride is deposited in these large number of pores and on the huge specific surface area in the oyster shells through an evaporation-condensation deposition process. The oyster shells after high-temperature calcination serve as a carrier to carry ferric chloride. The large number of pores and huge specific surface area allow ferric chloride to have more and greater contact opportunities, contact time, contact area and contact times with pollutants such as hydrogen sulfide, phosphate, and arsenate in sewage, thereby significantly improving the reaction probability, reaction time and number of reactions of the chemical reaction between ferric chloride and pollutants such as hydrogen sulfide, phosphate, and arsenate in sewage, and ultimately significantly improving the effect and efficiency of ferric chloride in purifying sewage. This is the second synergistic cooperation between CaO and ferric chloride in this application to improve quality and efficiency.

[0023] In summary, the two synergistic effects of CaO and ferric chloride in this application improve quality and efficiency. The powerful combination of CaO and ferric chloride significantly improves the effect and efficiency of purifying sewage by the sewage purifier prepared using oyster shells in this application. DETAILED DESCRIPTION

[0024] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. The embodiments described are only part of the embodiments of the present invention, not all of them. Therefore, based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0025] The present application provides a method for preparing a sewage purifier using oyster shells, comprising the following steps performed in sequence:

[0026] 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 30-100 μm, and calcining the oyster shell powder to obtain calcined powder;

[0027] 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump;

[0028] 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride;

[0029] 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder;

[0030] In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After cooling and deposition, the sewage purifier is obtained.

[0031] In one embodiment of the present application, in step 1), the calcination process is specifically as follows: first, heating the oyster shell powder to 240° C.-260° C. and keeping the temperature for 0.5 h-1 h;

[0032] The oyster shell powder is then heated to 750° C.-850° C. and kept warm for 2 h-4 h.

[0033] In one embodiment of the present application, in step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa.

[0034] In one embodiment of the present application, in step 3), the ferric chloride in the distillation kettle is heated to 240°C-260°C (at this time, the solid ferric chloride has not reached the melting point of 306°C and is therefore not melted. The evaporation at this time is the dry distillation or sublimation of the solid material), and the ferric chloride is stirred using a stirring blade installed in the distillation kettle, and the speed of the stirring blade is controlled to be 500-1000 r / min.

[0035] In one embodiment of the present application, in step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40°C-70°C.

[0036] In one embodiment of the present application, in step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 10%-30%.

[0037] In this application, the melting point of FeCl3 is 306°C and the density is 2.8 g / cm 3 , boiling point: 316℃, appearance: black-brown crystalline powder, solubility: easily soluble in water, insoluble in glycerol, easily soluble in methanol, ethanol, acetone, and ether; it can be seen that the boiling point of FeCl3 is low, and the boiling point of FeCl3 will drop to a lower level under vacuum, thereby achieving low-temperature evaporation.

[0038] In the present application, oyster shells are calcined under high temperature conditions. At 220°C, the organic matter in the oyster shells begins to undergo a pyrolysis reaction. The pyrolysis reaction ends at 800°C, and the calcite-type CaCO3 decomposes into CaO, releasing CO2, and forming a complex porous structure. After the CaO obtained by high-temperature calcination of the oyster shells is dissolved in water, the alkaline Ca(OH)2 produced has antibacterial and acidic wastewater neutralization effects. The oyster shells after high-temperature calcination not only have strong adsorption properties and ion exchange functions, but also have water purification effects.

[0039] The CaO (quicklime) in oyster shells calcined at high temperatures is mainly used in the treatment of industrial wastewater. When CaO enters the water, it decomposes into calcium ions and hydroxide ions. Phosphates and sulfates in the wastewater all turn into precipitates when they encounter calcium ions. The hydroxide ions entangle heavy metals, neutralizing the positive charge on the surface of the heavy metals and eliminating the repulsive force between them. The heavy metal ions then settle down along with the flocs formed by flocculants such as ferric chloride.

[0040] CaO itself has a certain adsorption capacity and can be used as a coagulant aid. Because it is strongly alkaline, CaO can adjust the pH, neutralize the acidic substances in the wastewater, and break the emulsion. It can treat complexes in industrial wastewater, inhibit the catalytic decomposition reaction of metal ions with hydrogen peroxide and hypochlorite, and improve the treatment rate of complex wastewater. It can sterilize and disinfect. The decomposed hydroxide ions can also oxidize some COD and ammonia nitrogen. Calcium ions can react with fluorine to form calcium fluoride precipitate.

[0041] Ferric chloride FeCl3 is an important water treatment agent. It is easily soluble in water and has strong water absorption. It can absorb moisture in the air and deliquesce. It is an organic synthesis catalyst. After reacting with hydroxide alkalinity in water, it generates a variety of hydrolysis products, which combine to form Fe(OH)3. These hydrolysis products have a lot of positive charges, so they can neutralize the negative charges on the colloidal particles and combine with negatively charged particles and ferric hydroxide. Due to this binding ability, it has flocculation ability and forms alum flowers. Ferric chloride reacts with hydrogen sulfide and phosphoric acid in water. Salt, arsenate and hydroxide alkalinity react chemically to form precipitates, which can precipitate heavy metals and sulfides in wastewater. The formed iron oxide flocs can adsorb substances that are difficult to degrade in water. It is a high-efficiency and low-cost flocculant for urban sewage and industrial wastewater treatment, with significant effects of precipitating heavy metals and sulfides, decolorizing, deodorizing, removing oil, sterilizing, removing phosphorus, and reducing effluent COD and BOD. In sewage treatment, the main role of ferric chloride is the role of the product after it reacts with hydroxide alkalinity as a coagulant and coagulant aid.

[0042] The methods and devices not fully described in the present invention are all prior art and will not be described in detail.

[0043] For a better understanding of the present invention, the present invention is further specifically described below through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0044] Example 1

[0045] A method for preparing a sewage purifier using oyster shells comprises the following steps performed in sequence:

[0046] 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 70-100 μm, and calcining the oyster shell powder to obtain calcined powder;

[0047] In step 1), the calcination process is specifically as follows: first, the oyster shell powder is heated to 260° C. and kept warm for 1 hour;

[0048] Then, the oyster shell powder was heated to 840°C and kept at this temperature for 4 h;

[0049] 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump;

[0050] In step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa;

[0051] 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride;

[0052] In step 3), the ferric chloride in the distillation kettle is heated to 240° C. and stirred by a stirring blade installed in the distillation kettle at a speed of 800 r / min;

[0053] 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder;

[0054] In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After the cooling and deposition are completed, the sewage purifier is obtained;

[0055] In step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40° C.-70° C.;

[0056] In step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 10%.

[0057] Example 2

[0058] A method for preparing a sewage purifier using oyster shells comprises the following steps performed in sequence:

[0059] 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 70-100 μm, and calcining the oyster shell powder to obtain calcined powder;

[0060] In step 1), the calcination process is specifically as follows: first, the oyster shell powder is heated to 245° C. and kept warm for 1 hour;

[0061] Then the oyster shell powder was heated to 850°C and kept at this temperature for 4 h;

[0062] 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump;

[0063] In step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa;

[0064] 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride;

[0065] In step 3), the ferric chloride in the distillation kettle is heated to 245° C. and stirred by a stirring blade installed in the distillation kettle at a speed of 800 r / min;

[0066] 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder;

[0067] In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After the cooling and deposition are completed, the sewage purifier is obtained;

[0068] In step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40° C.-70° C.;

[0069] In step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 15%.

[0070] Example 3

[0071] A method for preparing a sewage purifier using oyster shells comprises the following steps performed in sequence:

[0072] 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 80-100 μm, and calcining the oyster shell powder to obtain calcined powder;

[0073] In step 1), the calcination process is specifically as follows: first, the oyster shell powder is heated to 245° C. and kept warm for 40 minutes;

[0074] The oyster shell powder was then heated to 830°C and kept at this temperature for 4 h;

[0075] 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump;

[0076] In step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa;

[0077] 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride;

[0078] In step 3), the ferric chloride in the distillation kettle is heated to 243° C. and stirred by a stirring blade installed in the distillation kettle at a speed of 800 r / min;

[0079] 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder;

[0080] In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After the cooling and deposition are completed, the sewage purifier is obtained;

[0081] In step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40° C.-70° C.;

[0082] In step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 25%.

[0083] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for preparing a sewage purifier using oyster shells, characterized in that: The method includes the following steps: 1) cleaning the oyster shells, drying the oyster shells, crushing the oyster shells into powder with a particle size of 30-100 μm, and calcining the oyster shell powder to obtain calcined powder; 2) placing solid powdered ferric chloride in a distillation kettle, placing the calcined powder obtained in step 1) in a condenser connected to the distillation kettle, and evacuating the distillation kettle and the condenser using a vacuum pump; 3) then heating the ferric chloride in the still to evaporate it into gaseous ferric chloride; 4) The gaseous ferric chloride is pumped into the condenser, where it diffuses into the pores of the porous calcined powder and fully contacts the outer surface of the calcined powder; In the condenser, the gaseous ferric chloride is gradually cooled and turned into solid ferric chloride, which is deposited in the pores of the calcined powder and on the outer surface of the calcined powder. After the cooling and deposition are completed, the sewage purifier is obtained; In step 1), the calcination process is specifically as follows: first, the oyster shell powder is heated to 240° C.-260° C. and kept at this temperature for 0.5 h-1 h; Then, the oyster shell powder is heated to 750-850°C and kept at this temperature for 2-4 hours; Oyster shells are calcined under high temperature conditions. At 220°C, the organic matter in the oyster shells begins to undergo pyrolysis reaction. At 800°C, the pyrolysis reaction ends. The calcite-type CaCO3 decomposes into CaO, releasing CO2 and forming a complex porous structure.

2. The method for preparing a sewage purifier using oyster shells according to claim 1, characterized in that: In step 2), the vacuum degree in the distillation kettle and the condenser is controlled to be 1Pa-50Pa.

3. The method for preparing a sewage purifier using oyster shells according to claim 1, characterized in that: In step 3), the ferric chloride in the distillation kettle is heated to 240° C.-260° C., and the ferric chloride is stirred by a stirring blade installed in the distillation kettle, and the speed of the stirring blade is controlled to be 500-1000 r / min.

4. The method for preparing a sewage purifier using oyster shells according to claim 1, wherein: In step 4), the condenser is a water-cooled jacketed condenser, and the temperature of the calcined powder in the condenser is controlled to be 40° C.-70° C.

5. The method for preparing a sewage purifier using oyster shells according to claim 1, characterized in that: In step 4), the mass percentage of ferric chloride in the obtained sewage purifier is controlled to be 10%-30%.