CN-122006656-A - Acid mine wastewater modified red mud-based dearsenifying agent and preparation method and application thereof

Abstract

The invention discloses an acidic mine wastewater modified red mud-based dearsenifying agent, and a preparation method and application thereof. The preparation method of the dearsenization agent comprises the steps of placing red mud into acid mine wastewater for modification reaction, and sequentially carrying out solid-liquid separation, washing and drying, wherein the mass volume ratio of the red mud to the acid mine wastewater is 1-15 g/L, the pH value of the acid mine wastewater is 1-3, and the ferric iron concentration is 3-4 g/L. The dearsenization agent takes red mud as a matrix, and by utilizing the synergistic effect between the dearsenization agent and acid mine wastewater, the dearsenization capability of the red mud can be greatly improved by only dip modification, and based on the excellent performance of the red mud-based dearsenization agent, when the dearsenization agent is used for deep dearsenization of wastewater, the comprehensive deep removal of arsenic ions in different valence states can be realized by only adjusting the pH value of the system, and according to the test, when the dearsenization agent is used for deep dearsenization of the wastewater, the removal rate of trivalent arsenic can reach 94.47% and the removal rate of pentavalent arsenic can reach 99.99% when the pH value of the system is 12.

Inventors

• YANG BAOJUN
• Ding Zhichen
• LI YI
• KANG YANG
• QIU GUANZHOU
• WANG CHENXU
• WANG JUN
• Hong Maoxin
• LIU YANG
• LIU HONGCHANG
• CHANG XINGHUA
• LIAO RUI
• LIU SHITONG

Assignees

• 中南大学

Dates

Publication Date

20260512

Application Date

20250922

Claims (10)

1. 1. A preparation method of the acid mine wastewater modified red mud-based dearsenifying agent is characterized by comprising the steps of placing bayer process red mud into acid mine wastewater for modification reaction, and sequentially carrying out solid-liquid separation, washing and drying, wherein the mass volume ratio of the red mud to the acid mine wastewater is 1-15 g/L, the pH value of the acid mine wastewater is 1-3, and the ferric iron concentration is 3-4 g/L.
2. 2. The preparation method of the acid mine wastewater modified red mud-based dearsenifying agent, which is characterized in that the Bayer process red mud comprises, by mass, 8-10 parts of Fe, 1-1.5 parts of Al, 1-1.5 parts of Ca, 69-72 parts of S and 0.8-1 part of Mg.
3. 3. The preparation method of the acid mine wastewater modified red mud-based dearsenifying agent is characterized in that red mud is uniformly dispersed in acid mine wastewater, and reacted for 60-80 hours through a constant-temperature oscillating table at 25-35 ℃, wherein the rotating speed of the constant-temperature oscillating table is 150-200 r/min.
4. 4. The preparation method of the acid mine wastewater modified red mud-based dearsenifying agent, which is disclosed in claim 1, is characterized in that the washing process is to wash the solid obtained after solid-liquid separation by deionized water until the washing liquid is neutral, and the drying process is to dry the material to constant weight by a vacuum drying oven.
5. 5. An acidic mine wastewater modified red mud-based dearsenifying agent, which is characterized by being prepared by the preparation method of any one of claims 1-4.
6. 6. The application of the acid mine wastewater modified red mud-based dearsenifying agent is characterized in that the acid mine wastewater modified red mud-based dearsenifying agent is used for deep dearsenification of arsenic-containing wastewater, and is obtained by adding the dearsenifying agent into the arsenic-containing wastewater, adjusting the pH of a system to 2-12, removing arsenic for 4-8 hours under the oscillating condition, and then filtering and recycling the dearsenifying agent.
7. 7. The application of the acid mine wastewater modified red mud-based dearsenifying agent, which is disclosed in claim 6, is characterized in that the arsenic concentration in the arsenic-containing wastewater is 10-20 mg/L, and the addition amount of the dearsenifying agent is 0.5-1.5 g/L.
8. 8. The application of the acid mine wastewater modified red mud-based dearsenifying agent, which is disclosed in claim 6, is characterized in that when the arsenic-containing wastewater contains trivalent arsenic, the pH of the system is adjusted to 10-12, and when the arsenic-containing wastewater does not contain trivalent arsenic, the pH of the system is adjusted to 2-10.
9. 9. The application of the acid mine wastewater modified red mud-based dearsenifying agent, which is disclosed in claim 6, is characterized in that a constant-temperature oscillating table is adopted in the oscillating process, and the condition is that the temperature is 25-35 ℃ and the rotating speed is 150-200 r/min.
10. 10. The application of the acid mine wastewater modified red mud-based dearsenifying agent according to claim 6, wherein the filtering process adopts a microporous filter membrane for suction filtration, and the pore diameter of the microporous filter membrane is less than or equal to 0.45 μm.

Description

Acid mine wastewater modified red mud-based dearsenifying agent and preparation method and application thereof Technical Field The invention relates to an arsenic-containing wastewater dearsenization agent, in particular to an acid mine wastewater modified red mud-based dearsenization agent, and a preparation method and application thereof. Background Arsenic is widely distributed in the natural environment and is considered to be one of the most toxic metals due to its carcinogenicity and teratogenicity. Contaminated water and food can enter the human body in a direct and indirect manner and accumulate in internal organs, resulting in chronic arsenic poisoning, while excessive intake of arsenic can even lead to death. Currently, various remediation methods, such as coagulation and flocculation, adsorption, bio-adsorption, ion exchange and membrane filtration, are used to reduce arsenic contamination in water. Although these methods are effective for arsenic remediation, there are still some problems and limitations associated with their use, such as cost and sludge management. Among these techniques, adsorption is a common process that produces less sludge or toxic intermediates and is flexible in design and operation. The red mud is an overbased waste generated in the alumina industrial production process, and the amount of the red mud generated per 1 ton of alumina produced is about 1.0-1.5 tons. The red mud has strong alkalinity, high salt content and high pollutant migration risk. Pyrite is also a mining and metallurgical waste. Acid mine wastewater is produced primarily by oxidation of sulfide minerals upon exposure to air, water and microbial activity, and is widely found in active or abandoned polymetallic sulfides and coal mines. Acidic mine wastewater is strongly acidic and typically contains high concentrations of sulfate and dissolved metal ions. Untreated acidic mine wastewater discharge presents a risk of contaminating nearby water sources, animals and plants. How to reasonably dispose and treat red mud and acid mine wastewater is one of the most significant challenges facing the global mining industry. In recent years, many researchers have focused on red mud and pyrite to repair arsenic-contaminated water bodies. The red mud can adsorb arsenic by forming an inner complex of iron minerals and arsenic, and can fix arsenic by ligand exchange and iron-arsenic coprecipitation. However, red mud is a material for adsorbing arsenic, the adsorption performance is poor, modification treatment is needed, and related researches on dearsenification by taking red mud as a matrix are still rarely reported. Disclosure of Invention Aiming at the problems existing in the prior art, the first aim of the invention is to provide an acid mine wastewater modified red mud-based dearsenifying agent. The dearsenization agent takes red mud as a matrix, and can greatly improve the dearsenization capability of the red mud only through impregnation modification by utilizing the synergistic effect between the dearsenization agent and the acid mine wastewater, and the modification process mainly utilizes alkaline groups in the red mud to perform Lewis acid-alkali reaction with the acid mine wastewater to promote the ferric ions in the acid mine wastewater to hydrolyze on the surfaces of red mud particles, so that the red mud-based dearsenization agent with iron/aluminum functional groups enriched on the surfaces is formed. The second aim of the invention is to provide a preparation method of the acid mine wastewater modified red mud-based dearsenifying agent. The method has the advantages of simple flow, easy operation and the like, and the adopted raw materials are mining waste materials and waste liquid, so that the cost of the raw materials is greatly reduced, the problem of difficult waste digestion is effectively solved, and the technical purpose of treating waste by waste is realized. The third purpose of the invention is to provide an application of the acid mine wastewater modified red mud-based dearsenifying agent for deep dearsenification of arsenic-containing wastewater. Based on the excellent performance of the red mud-based dearsenifying agent, when the red mud-based dearsenifying agent is used for deep dearsenification of wastewater, the comprehensive deep removal of arsenic ions in different valence states can be realized only by adjusting the pH of the system, even if trivalent arsenic which is difficult to remove in the wastewater is subjected to oxidation pretreatment without adding any strong oxidant, and according to tests, when the dearsenification agent is used for deep dearsenification of the wastewater, the removal rate of trivalent arsenic can reach 94.47% and the removal rate of pentavalent arsenic can reach 99.99% when the pH of the system is 12. The invention provides a preparation method of an acid mine wastewater modified red mud-based dearsenifying agent, which comprises the steps of placing