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Method for removing arsenic in calcium-rich high-arsenic groundwater by using biochar

A groundwater and biochar technology, applied in the treatment of polluted groundwater/leachate, chemical instruments and methods, water pollutants, etc., can solve the problems of complex operation, low efficiency and high operating cost, and achieve simple operation and treatment Long-lasting effect and the effect of reducing secondary pollution

Active Publication Date: 2019-08-20
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] In view of the above defects or improvement needs of the prior art, the purpose of the present invention is to provide a method for removing arsenic in calcium-rich and high-arsenic groundwater with biochar, and use specific calcium-rich and high-arsenic groundwater as the object to be removed. When biochar is added to groundwater, the oxidative active groups on the surface of biochar are used to oxidize low-valence arsenite in groundwater to high-valence arsenate, and the generated arsenate combines with calcium ions and biochar to form arsenic-calcium - Biochar precipitation, making full use of the calcium-rich and alkaline characteristics of groundwater, organic combination of oxidation and adsorption means to achieve the purpose of integrated removal of arsenic in groundwater, compared with the existing technology, it can effectively solve the existing problems in the removal of arsenic in groundwater The processing methods generally have problems such as low efficiency, high operating costs and complicated operations.

Method used

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  • Method for removing arsenic in calcium-rich high-arsenic groundwater by using biochar
  • Method for removing arsenic in calcium-rich high-arsenic groundwater by using biochar
  • Method for removing arsenic in calcium-rich high-arsenic groundwater by using biochar

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Embodiment 1

[0036] In the present invention, the rice husks of the prepared biochar are all taken from an agricultural breeding base in Hubei. The retrieved rice husks were washed several times with deionized water to remove impurities, and then placed in an electric blast drying oven for 12 hours (80°C). And seal it in a ziplock bag for later use. Then weigh 30g of rice husk into the silicon carbide reactor and cover it (isolate oxygen), place it in a muffle furnace at 400°C for 1h with limited oxygen pyrolysis (no gas is introduced during the pyrolysis process), wait to cool to room temperature, The biochar was washed twice with deionized water.

[0037] The specific cleaning procedure is as follows: put in a 2L beaker, add 2L of deionized water, put it on a magnetic stirrer and stir at a speed of 600r / min for 12h, filter (medium-speed filter paper, 30-50μm), and the obtained solid is again washed in the same way as above The step of washing 12h and filtering. The finally obtained so...

Embodiment 2

[0039] Take 100mL of calcium-rich, high-arsenic and alkaline groundwater (calcium ion concentration is 0.05mol / L, trivalent arsenic concentration is 7.5mg / L, pH=9.0), add 0.2g biochar, and place the reaction bottle in a water bath Medium seal (although a water bath is used, the water bath is only used to provide a sealed reaction vessel without heat treatment; the water temperature can be kept at the initial state temperature, such as 27 ° C), the stirring rate is 600r / min, continuous stirring, respectively Samples were taken at 0, 0.5, 1, 2, 3, 4, 6, 8, 12 and 24 hours of reaction, and the arsenic was analyzed by HPLC-AFS to obtain the removal efficiency of arsenic.

[0040] like Figure 5 Shown, the removal efficiency of arsenic can reach 80% within 24h.

Embodiment 3

[0042] In Example 2, when the groundwater pH=11.0 is selected, the removal efficiency of arsenic by biochar.

[0043] like Figure 6 As shown, the removal efficiency of arsenic can reach 100% within 24 hours, and the removal effect of arsenic is enhanced with the increase of pH.

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Abstract

The invention discloses a method for removing arsenic in calcium-rich high-arsenic groundwater by using biochar, belonging to the field of arsenic pollution treatment for groundwater. The method comprises the following steps: adding biochar into alkaline calcium-rich high-arsenic groundwater, and carrying out a stirring reaction for at least 4 hours to remove arsenic dissolved in the groundwater,wherein the concentration of arsenic contained in the groundwater is 0.1-10 mg / L, and the concentration of calcium ions is 20-2000 mg / L. According to the invention, the specific calcium-rich high-arsenic groundwater is used as the object in which arsenic is to be removed; oxidizing active groups on the surface of the biochar are employed to oxidize low-valent arsenite in the groundwater into high-valent arsenate, and the generated arsenate reacts with the calcium ions and biochar to formation an arsenic-calcium-biochar precipitate; so the characteristic that the groundwater is rich in calciumand is alkaline is fully utilized, oxidation and adsorption means are organically combined to achieve the purpose of integrated removal of arsenic from the groundwater, and the method can effectivelysolve the common problems of low efficiency, high operating cost, complicated operation and the like in conventional methods for removing arsenic in groundwater.

Description

technical field [0001] The invention belongs to the field of arsenic pollution treatment in ground water, and more specifically relates to a method for removing arsenic in ground water rich in calcium and high in arsenic by using biochar. Background technique [0002] As a toxic and carcinogenic metalloid, arsenic is widely distributed in groundwater worldwide, and there is a potential problem of arsenic pollution in drinking water. Long-term exposure to arsenic-containing environments can lead to skin cancer, liver cancer, and cardiovascular and other diseases in the human body. The World Health Organization lists arsenic as a class I carcinogen. my country's "Drinking Water Hygienic Standards" (GB5749-2006) also reduced the concentration of arsenic in drinking water from 50 μg / L to 10 μg / L. According to my country's groundwater standards, at least tens of millions of people are affected by arsenic-containing groundwater, especially in the arid and semi-arid areas of nort...

Claims

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Application Information

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IPC IPC(8): C02F1/72C02F1/52B09C1/00C02F101/10C02F101/20C02F103/06
CPCB09C1/002C02F1/5209C02F1/72C02F2101/10C02F2101/103C02F2101/20C02F2103/06
Inventor 陈静赵泽州王琳玲李鸿博钟德来任树鹏尹文利
Owner HUAZHONG UNIV OF SCI & TECH
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