Method for treating wastewater containing trivalent arsenic through seed crystal induction and application of method

A technology for treating wastewater and trivalent arsenic, which is applied in chemical instruments and methods, water/sludge/sewage treatment, flocculation/sedimentation water/sewage treatment, etc. It can solve the problems of large volume and poor settling performance of hydrotalcite-like, Achieve excellent application effects, highly stable arsenic-containing precipitation, and reduce costs

Pending Publication Date: 2022-04-12
CENT SOUTH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0006] The Chinese invention patent application with publication number CN201910464225.5 discloses a method using Zn 2+ with Fe 2+ As metal ions and sodium hydroxide are added dropwise into the trivalent arsenic solution at the same time to regulate the formation of hydrotalcite-like; this method can well achieve the immobilization and stabilization of trivalent arsenic, but the formed hydrotalcite-like sedimentation Poor, the product is fluffy and flocculent, with a large volume

Method used

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  • Method for treating wastewater containing trivalent arsenic through seed crystal induction and application of method
  • Method for treating wastewater containing trivalent arsenic through seed crystal induction and application of method
  • Method for treating wastewater containing trivalent arsenic through seed crystal induction and application of method

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Embodiment 1

[0049] In the embodiment of the present invention, the effects of different dosages of crystal seeds on the effluent arsenic concentration of trivalent arsenic wastewater treated with hydrotalcites induced by seeds, the arsenic toxicity leaching of solid products, and the sludge sedimentation ratio of arsenic-containing sludge were compared, specifically The implementation process is as follows:

[0050] Will contain 100ml As 3+ The 500mL beaker of the solution (100mg / L in terms of arsenic concentration) was placed in a constant temperature water bath, and 0g / L, 0.33g / L, 1g / L, 1.5g / L, 2g / L were added at the beginning of the reaction , 2.5g / L and 3g / L ZnFe-LDHs as seeds, and kept stirring, the stirring speed was set to 500rppm, the temperature of the water bath was 25°C, and the As was adjusted with dilute sulfuric acid and NaOH 3+ The initial pH of the solution was 8; the injection rate was controlled by a peristaltic pump, and the prepared mixed metal salt solution (100mL0.0...

Embodiment 2

[0056] The embodiment of the present invention compares the influence of different reaction pH on the effluent arsenic concentration and the toxic leaching of solid products and the sludge sedimentation ratio of arsenic-containing sludge for the treatment of trivalent arsenic wastewater by seed crystal-induced hydrotalcite-like formation. The specific implementation process is as follows:

[0057] Will contain 100ml As 3+ The 500mL beaker of the solution (concentration in terms of arsenic is 100mg / L) is placed in a constant temperature water bath, and 2.5g / L of ZnFe-LDHs is added as a seed crystal at the beginning of the reaction, and it is constantly stirred, and the stirring speed is set to 500rppm. The temperature of the water bath was 25 °C, and the As was adjusted with dilute sulfuric acid and NaOH 3+ The initial pH of the solution was adjusted to 7, 8, 9, 10, and 11 respectively; the injection rate was controlled by a peristaltic pump, and the prepared mixed metal salt s...

Embodiment 3

[0061] The embodiment of the invention has compared different Zn 2+ and Fe 2+ The molar ratio of seed crystals induces the formation of hydrotalcites to treat trivalent arsenic wastewater, the effluent arsenic concentration and the toxic leaching of solid products and the sludge sedimentation ratio of arsenic-containing sludge. The specific implementation process is as follows:

[0062] will be filled with 100m1 As 3+ The 500mL beaker of the solution (concentration in terms of arsenic is 100mg / L) is placed in a constant temperature water bath, and 2.5g / L of ZnFe-LDHs is added as a seed crystal at the beginning of the reaction, and it is constantly stirred, and the stirring speed is set to 500rppm. The temperature of the water bath was 25 °C, and the As was adjusted with dilute sulfuric acid and NaOH 3+ The initial pH of the solution was 7; the injection rate was controlled by a peristaltic pump, and the prepared mixed metal salt solution (100mL ZnSO 4 +FeSO 4 ) and NaOH so...

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Abstract

The invention discloses a method for treating wastewater containing trivalent arsenic by seed crystal induction and application thereof, and the method comprises the following steps: adding zinc-iron hydrotalcite seed crystal into wastewater to be treated containing trivalent arsenic, slowly dropwise adding a sodium hydroxide solution and a mixed metal salt solution containing Fe < 2 + > and Zn < 2 + > at the same time, stirring to react, and controlling the pH value of a reaction system to be greater than 7 and constant; and after standing, carrying out solid-liquid separation, thereby obtaining the product. According to the method for treating the wastewater containing the trivalent arsenic through seed crystal induction, the hydrotalcite-like compound with a layered structure can be obtained, so that the purposes of efficiently treating the trivalent arsenic in the wastewater and forming highly-stable arsenic-containing precipitates are achieved, and the arsenic toxicity leaching concentration is obviously lower than that of the arsenic-containing precipitates obtained in an existing precipitation method; the practical application effect is excellent; the volume of the hydrotalcite-like arsenic-containing sludge formed by the method for treating the trivalent arsenic-containing wastewater through seed crystal induction provided by the invention is reduced by 97.37%, and the subsequent treatment cost is greatly reduced.

Description

technical field [0001] The invention relates to the technical field of sewage treatment, in particular to a method for inducing treatment of trivalent arsenic-containing wastewater by seed crystals and its application. Background technique [0002] Arsenic is a toxic metalloid element, and its content ranks 20th among the abundance elements in the earth's crust, 14th in seawater, and 12th in the human body. Once arsenic enters the environment, it will undergo chemical or biological transformation, and will have a continuous impact on the ecological environment and human health in different forms through media such as water and soil; after arsenic enters the human body, it will cause acute or chronic poisoning, affect the defense system of the human body, and promote biological pollution. Body mutagenesis, and may lead to renal failure and death of organisms. Arsenic-containing wastewater mainly contains As 3+ (arsenite) and As 5+ (arsenate) form exists, and As 3+ than As...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C02F101/10
Inventor 李青竹周泽艳王庆伟柴立元林璋杨志辉杨卫春肖睿洋
Owner CENT SOUTH UNIV
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