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Method for treating chrome tanning wastewater

A treatment method and wastewater technology, which is applied in animal processing wastewater treatment, neutralized water/sewage treatment, water/sewage multi-stage treatment, etc., can solve steric hindrance or space mismatch, poor removal effect of heavy metals, small molecules Precipitant residues and other problems, to achieve a high degree of reaction completion, excellent treatment effect, conducive to the formation and growth of the effect

Inactive Publication Date: 2019-07-12
ZHEJIANG OCEAN UNIV
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  • Abstract
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AI Technical Summary

Problems solved by technology

However, the use of small molecule heavy metal chelating flocculants to treat chromium-containing wastewater forms smaller particles and poor settling performance. Generally, it is necessary to add auxiliary (flocculation) coagulants, and small molecule precipitants tend to remain in the treated water, causing secondary pollution.
In the traditional polymer chelating agent, the chelating group and the heavy metal ion combine to produce electrical neutralization, which makes the polymer chain curl up and produce flocculation, which has better flocculation and sedimentation effect than the small molecule heavy metal precipitant. The amount is also small, but there are steric hindrance or space mismatch, resulting in the formation of micro flocs with excess negative charges, the repulsion of the same charge makes it difficult for micro flocs to form and grow into large flocs, flocculation and sedimentation Poor performance, poor removal of heavy metals

Method used

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  • Method for treating chrome tanning wastewater
  • Method for treating chrome tanning wastewater
  • Method for treating chrome tanning wastewater

Examples

Experimental program
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Effect test

Embodiment 1

[0034] A flocculant used for the treatment of chrome tanning wastewater, the flocculant includes a chitosan-derived adsorption material; the chitosan-derived adsorbent is prepared by the following steps: dispersing triethylenetetramine and chitosan in an acetic acid solution , and then add a cross-linking agent to react, then wash and dry to obtain the product; the above-mentioned cross-linking agent contains glutaraldehyde, triethanolamine and 3-mercaptopropionic acid. Chitosan, a natural high molecular polymer, is an amino polysaccharide with cationic polyelectrolyte properties, and has good biocompatibility. It can undergo ion exchange with anionic compounds under acidic conditions. Or organic pollutants have numerous adsorption sites, so chitosan-derived materials have broad application prospects in wastewater treatment.

[0035] The chitosan-derived adsorption material is prepared through the following specific steps: take triethylenetetramine and chitosan in a ratio of 1...

Embodiment 2

[0050] The processing method of chrome tanning waste water, it specifically comprises the following steps:

[0051] 1) Grille removal of impurities: the chrome tanning wastewater is passed through the grid to remove impurities, the mesh screen used is 40 mesh, and the hydraulic retention time is 3h;

[0052] 2) Alkali adjustment: add 4.2kg / t of sodium hydroxide solution to the waste water after impurity removal for precipitation treatment, and adjust the pH value of the waste water to 8, and then recover the resulting precipitate, which can be recovered by acid hydrolysis For tanning process;

[0053] 3) Wastewater settlement: add 33L / m to the waste water 2 After flocculant, react at a stirring speed of 80r / min for 30min, then let it stand for 1h, then send the supernatant to the adjustment tank, after the lower layer is precipitated and filtered, the filtrate is sent to the adjustment tank, and the filter residue is sent to the sludge drying tank. The weight ratio of the am...

Embodiment 3

[0061] In this example, the preparation of the amphoteric polymer chelating flocculant PDDMAMDTC used in the flocculant is optimized, and the specific optimization measures are as follows:

[0062] Step 1, take dimethyl diallyl ammonium chloride and acrylamide monomers at a molar ratio of 0.5:1, add deionized water to dissolve and prepare a mixed solution with a mass concentration of 23.5%, and then inject nitrogen to drive oxygen for 30 minutes, Then add 0.16wt% ammonium persulfate, 0.04% sodium oxalate and 0.02% dimethyl sulfoxide to the mixed solution, react at a temperature of 65°C for 1.5h, and rinse with methanol to obtain the copolymer P(DMDAAC -AM), as the cationic degree of the copolymerized product increases, the steric effect and charge repulsion effect formed after the addition of the cation is also enhanced, which will reduce the reactivity of the monomer in the system, and also inhibit the continuation of the intrinsic viscosity of the polymerized product. growth...

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Abstract

The invention provides a method for treating chrome tanning wastewater, and belongs to the technical field of wastewater treatment. The method comprises the steps: performing grid impurity removal, performing adjustment through addition of alkali, performing wastewater sedimentation, and performing adjustment through addition of acid, wherein wastewater sedimentation is performed through a flocculating agent, and the flocculating agent comprises an amphoteric polymer chelating flocculant PDMAMDTC and a chitosan-derived adsorption material; and preparation of the chitosan-derived adsorption material comprises the following steps: dispersing triethylene tetramine and chitosan in an acetic acid solution, then adding a cross-linking agent for a reaction, and then performing washing and drying,and the cross-linking agent contains glutaraldehyde, triethanolamine and 3-mercaptopropionic acid. According to the method for treating the chrome tanning wastewater, a short reaction period of timeis required, the efficiency of decontamination and impurity removal is high, full recycling and utilization of resources are achieved, and the cost of production and treatment is reduced effectively;and the flocculating agent has the advantages of a high degree of reaction completion, low surface energy, high cationic degree, high intrinsic viscosity, large ion adsorption capacity, strong net trapping ability and good performance of flocculation and sedimentation.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and in particular relates to a treatment method for chrome tanning wastewater. Background technique [0002] my country is the largest leather goods manufacturing country in the world. Chrome tanning is an important process of leather production and the only process that produces heavy metal pollution sources. The chrome tanning wastewater generated in this process is one of the most difficult industrial wastewater to treat. At present, the amount of wastewater produced by the leather industry is about 80 million tons per year, accounting for 1.6% of my country's industrial wastewater discharge. It can be seen that the pollutants brought by the leather industry to the environment are quite serious. [0003] A large amount of chromium-containing wastewater discharged from the leather industry comes from the four processes of raw hide processing, tanning, neutralization, and dyeing and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/56C02F9/04B01J20/26B01J20/30C02F101/20C02F103/24
CPCB01J20/264C02F1/001C02F1/56C02F1/66C02F9/00C02F2001/007C02F2101/20C02F2103/24
Inventor 马玉心
Owner ZHEJIANG OCEAN UNIV
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