Bentonite is a type of claystone with montmorillonite as the main mineral, also known as smectite clay, and bentonite is a commercial name. In this paper, organic bentonite mainly refers to quaternary ammonium salt cationic surfactant modified bentonite.
Bentonite has a large specific surface area and ion exchange capacity, good adsorption properties; can be used for wastewater adsorption of heavy metals and other pollutants. Due to the strong hydrophilicity of the siloxane structure on the surface of bentonite and the hydrolysis of interlayer cations, the unmodified bentonite (native soil) has poor performance in the adsorption and treatment of organic compounds. Therefore, people use quaternary ammonium cationic surfactant modified bentonite, organic or organic - inorganic composite bentonite, greatly improving the adsorption properties of bentonite, its removal of organic matter in water than the original high tens to hundreds of times. Organic bentonite can be used as an adsorbent to collect organic pollutants from atmospheric particulate matter. It can be used as a chromatographic medium to separate gaseous organic compounds. It can also be used as a hazardous waste stabilizer to effectively prevent the migration of organic pollutants. Organic bentonites can pollute groundwater and soil The applied research on the restoration has also made great progress. But so far the most studied organic bentonite is used for adsorption and treatment of organic pollutants in water, and the adsorption mechanism, rules and influencing factors made a more in-depth study.
Bentonite in water treatment can be traced back to the 1930s. In 1934 Smith found that montmorillonite can absorb organic cations such as hydrazine from aqueous solutions. In 1937, Olin et al. Used bentonite as a coagulant to treat water and wastewater. In 1950 Jo rdan and other organic salts found to be appropriate and after the reaction, the expansion of bentonite, hydrophobic properties were enhanced; Barrer and M acleod other found in 1955, the bentonite cations between tetramethyl or tetraethyl ammonium exchange The layer spacing increases, adsorption capacity has also been enhanced. But until the 1960s, bentonite was gradually used to adsorb the organic matter in water. Since the 1980s, great progress has been made in the application of bentonite in environmental protection. It is mainly used for wastewater treatment, oil treatment, waste plastics treatment, municipal waste treatment, air purification and waste gas treatment, radioactive waste and hazardous waste treatment Among them, the most used for wastewater treatment, especially organic bentonite greatly improve the adsorption capacity of bentonite to improve the removal of organic matter in wastewater. The organic bentonite removal of organic pollutants in water mechanism, rules and influencing factors in-depth study of organic bentonite recycling study and promote the organic bentonite in wastewater treatment.
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