A method for removing arsenic from calcium-rich and high-arsenic groundwater by using biochar

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...

AI Technical Summary

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.

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