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Method for treating wastewater with trivalent arsenic

A technology for treating wastewater and trivalent arsenic, which is used in water/sewage treatment, chemical instruments and methods, water/sludge/sewage treatment, etc. High cost, difficulty in secondary pollution operation, etc., to achieve the effect of controllable arsenic removal process, good effect, and low addition amount

Active Publication Date: 2017-08-04
CENT SOUTH UNIV
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  • Abstract
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Problems solved by technology

[0003] In the prior art, the wastewater containing trivalent arsenic is mainly treated by iron salt precipitation method, which is limited by the solubility product and needs to consume a large amount of alkali and iron salt to make the removal rate of trivalent arsenic reach the standard, and at the same time lead to a large amount of waste residue The production, and its long-term stability can not meet the needs of practical applications, there are problems such as high cost, secondary pollution and difficult operation
[0004] In recent years, methods such as ion exchange, reverse osmosis, and biological arsenic removal, which have developed rapidly in recent years, have been used to remove arsenic in wastewater, and have achieved good results. However, the cost of ion exchange and reverse osmosis is relatively high, and they are limited to small The treatment of low-concentration arsenic-containing wastewater with a single scale and single component; and the biological arsenic removal method has the potential to directly treat trivalent arsenic-containing wastewater without oxidation, and has good safety, and has gradually been favored by many researchers. However, the actual On the one hand, the biological arsenic removal method needs to cultivate microorganisms, which takes a long time, and the arsenic removal effect of different microorganisms varies greatly, and the actual arsenic removal operation is not easy to control. On the other hand, the biological oxidation used in this method forms minerals to achieve The reaction process of removing arsenic takes a long time and must be carried out under harsher reaction conditions

Method used

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  • Method for treating wastewater with trivalent arsenic
  • Method for treating wastewater with trivalent arsenic
  • Method for treating wastewater with trivalent arsenic

Examples

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Effect test

Embodiment 1

[0036] This example provides a method for treating wastewater containing trivalent arsenic. The specific process is as follows: using arsenous acid, ferric nitrate and sodium sulfate as raw materials respectively, preparing As 3+ Arsenic-containing solution with a concentration of 9g / L (calculated as arsenic), Fe 3+ Concentration of 11.2g / L iron salt solution and SO 4 2-The sulfate solution with a concentration of 3.2g / L was used for standby; the three solutions were slowly added into a 250mL three-necked flat-bottomed flask filled with 30mL deionized water bottom liquid at the same time through a peristaltic pump at a rate of 1.5mL / min, and the materials were fully collided and contacted at the same time. The control temperature is 25±1°C, the stirring speed is 600±20r / min, the pH=2.4, the feeding time is 20min, the timing is started at the same time as feeding, and the reaction is 25min. Take a sample of 2.5ml and detect its As 3+ Concentration of As 3+ The removal rate ...

Embodiment 2

[0038] This example provides a method for treating wastewater containing trivalent arsenic. The specific process is as follows: using arsenous acid, ferric nitrate and sodium sulfate as raw materials respectively, preparing As 3+ Arsenic-containing solution with a concentration of 15g / L (calculated as arsenic), Fe 3+ Concentration of 16.8g / L iron salt solution and SO 4 2- The sulfate solution with a concentration of 4.8g / L was used for standby; the three solutions were slowly added into a 250mL three-necked flat-bottomed flask filled with 30mL of deionized water bottom liquid through a peristaltic pump at the same time at a rate of 1.5mL / min, and the materials were fully collided and contacted at the same time. The control temperature is 25±1°C, the stirring speed is 600±20r / min, the pH=2.4, the feeding time is 20min, the timing is started at the same time as feeding, and the reaction is 25min. Take a sample of 2.5ml and detect its As 3+ Concentration of As 3+ The removal ...

Embodiment 3

[0040] This example provides a method for treating wastewater containing trivalent arsenic. The specific process is as follows: using arsenous acid, ferric nitrate and sodium sulfate as raw materials respectively, preparing As 3+ Arsenic-containing solution with a concentration of 20.5g / L (calculated as arsenic), Fe 3+ Concentration of 23.0g / L iron salt solution and SO 4 2- The sulfate solution with a concentration of 6.56g / L was used for standby; the three solutions were slowly added into a 250mL three-necked flat-bottomed flask filled with 30mL of deionized water bottom liquid at the same time through a peristaltic pump at a rate of 1.5mL / min, and the materials were fully collided and contacted at the same time. The control temperature is 25±1°C, the stirring speed is 600±20r / min, the pH=2.4, the feeding time is 20min, the timing is started at the same time as feeding, and the reaction is 25min. Take a sample of 2.5ml and detect its As 3+ Concentration of As 3+ The remov...

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Abstract

The invention discloses a method for treating wastewater with trivalent arsenic. The method includes simultaneously feeding the to-be-treated wastewater with the trivalent arsenic, iron salt solution and sulfate solution and simultaneously sufficiently colliding the to-be-treated wastewater, the iron salt solution and the sulfate solution with one another to obtain first mixtures; regulating the pH (potential of hydrogen) of the first mixtures until the pH of the first mixtures reaches 1.8-3.0; uniformly mixing the first mixtures with one another at the normal temperature; carrying out reaction; separating precipitates. The method has the advantages that feeding reaction is carried out under the conditions of the temperatures of 25+ / -1 DEG C, the speeds of 600+ / -20 r / min and the pH of 2.4 for 18 min when the arsenic solution with the As <3+> content of 20.5 g / L, the iron salt solution with the Fe <3+> content of 23.0 g / L and the sulfate solution with the SO<4><2-> content of 6.56 g / L are added into 30 mL of deionized water at the speeds of 1.8 mL / min, water hydroxyl sarmientite minerals are good in crystallization, and the As <3+> removal rate is 87.6%; the method for treating the wastewater with the trivalent arsenic is high in arsenic removal efficiency, good effects can be realized, raw materials are low in cost and are easily available, conditions are mild, procedures can be controlled, the precipitates are high in arsenic content, are stable and are easy to separate, secondary pollution can be prevented, and accordingly the method has a broad practical application prospect.

Description

technical field [0001] The invention belongs to the technical field of wastewater treatment, and more specifically relates to a method for treating wastewater containing trivalent arsenic. Background technique [0002] With the continuous development of my country's non-ferrous metal smelting industry, wastewater containing trivalent arsenic has the characteristics of high acidity, high content of trivalent arsenic, and complex components, which seriously threatens environmental safety and residents' health, and has gradually attracted widespread attention. Nowadays, The recovery and treatment of arsenic-containing pollutants, especially trivalent arsenic-containing pollutants, has become the most difficult problem that my country's non-ferrous metal smelting industry must face. [0003] In the prior art, the wastewater containing trivalent arsenic is mainly treated by iron salt precipitation method, which is limited by the solubility product and needs to consume a large amou...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F1/52C02F101/10
CPCC02F1/5236C02F2001/5218C02F2101/103
Inventor 李青竹王庆伟张观石柴立元闵小波杨志辉王海鹰
Owner CENT SOUTH UNIV
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