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Method for processing lead and chromium in wastewater

A technology for treating waste water and waste water, applied in chemical instruments and methods, water/sewage multi-stage treatment, water/sludge/sewage treatment, etc., can solve problems such as troublesome operation and low removal rate of heavy metals, and achieve high treatment efficiency Effect

Inactive Publication Date: 2012-12-19
SHANGHAI FENGXIN ENVIRONMENTAL PROTECTION TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is: in order to overcome the problems in the prior art that the removal rate of heavy metals in wastewater treatment is not high, the treated wastewater needs to be treated again, and the operation is troublesome, etc., a method for treating lead and chromium in wastewater is provided. method

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0014] Treat 150L of waste water, the pH of the waste water is 7. First, add a sodium sulfide solution with a mass concentration of 0.1 g / L to the wastewater, and the molar ratio of sodium sulfide to hexavalent chromium is 1.5:1, so that all the hexavalent chromium in the wastewater is reduced to trivalent, and zinc sulfide, etc. can be generated at the same time. Insoluble precipitation; then add 1L of NaOH with a mass concentration of 40g / L to the wastewater and stir, then the remaining zinc ions and trivalent chromium will all combine with hydroxide to form precipitates, and the pH of the wastewater will reach above 10; The heavy metals lead and chromium are separated from the wastewater by precipitation and filtration; after that, hydrochloric acid is added to adjust the pH to neutral before the water is released.

Embodiment 2

[0016] Treat 300L waste water, the pH of the waste water is 7. First, add a sodium sulfide solution with a mass concentration of 0.1g / L to the wastewater, and the molar ratio of sodium sulfide to hexavalent chromium is 2:1, so that all the hexavalent chromium in the wastewater can be reduced to trivalent, and zinc sulfide can be generated at the same time. Insoluble precipitation; then add 2L of NaOH with a mass concentration of 40g / L to the wastewater and stir, then the remaining zinc ions and trivalent chromium will all combine with hydroxide to form a precipitate, and the pH of the wastewater will reach above 10; The heavy metals lead and chromium are separated from the wastewater by precipitation and filtration; after that, sulfuric acid is added to adjust the pH to neutral before the water is released.

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PUM

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Abstract

The invention discloses a method for processing lead and chromium in wastewater and is characterized in that the method is realized by the following steps of: firstly, adding a sodium sulfide solution with the mass concentration of 0.1g / L into wastewater so as to completely reduce hexavalent chromium in the wastewater to trivalent chromium and simultaneously generate hard-soluble precipitates such as zinc sulfide and the like; then, adding strong base into the wastewater, and stirring such that residual zinc ions and trivalent chromium completely bond with hydroxide to generate a precipitate; and finally, separating heavy metals--lead and chromium from the wastewater by a precipitation filtration mode. By the adoption of the method for processing the wastewater, the processing efficiency is high and the wastewater basically contains no heavy metal elements. The method provided by the invention is simple to operate and causes no secondary pollution.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment methods, in particular to a method for treating lead and chromium in wastewater. Background technique [0002] Heavy metals in water bodies are not easy to be decomposed by microorganisms, and some heavy metals and their compounds are easily absorbed by organisms and accumulate step by step through the food chain, resulting in huge enrichment and affecting the quality of aquatic products. All chromium compounds are toxic. Hexavalent chromium is a teratogenic, carcinogenic, and mutagenic substance. Chromium is much more toxic to invertebrates than to fish. Oysters are most sensitive to chromium, 10-12ug Chromium / L can cause the death of oysters, and some phytoplankton can concentrate chromium in water by 2300 times; lead is a cumulative poison, which can cause red blood cell hemolysis, liver and kidney damage, and damage male gonads, nervous system and blood vessels. [0003] In the p...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04
Inventor 夏志先张金山
Owner SHANGHAI FENGXIN ENVIRONMENTAL PROTECTION TECH