| Bentonites, a new kind of environmental adsorption material, have been widely used in the environmental pollution control and remediation. In this dissertation, the structure and properties of bentonite and the character of organobentonite have been described. The study progress and mechanism of bentonites in treating organic pollutants, heavy metals and other pollutants in water have been mainly summarized, and the trend of its application in wastewater treatment have also been forecasted.The sorption of surfactants in complex system on bentonites has been firstly investigated. Based upon that, the most economical and fitting dosage of surfactant in the process of treating organic wastewater by "bentonite + surfactant" mixture system directly, and the problem of the secondary pollution of surfactant have been studied. Finally, the embed-immobilization technique of bentonite has been mainly investigated to find out the best conditions of preparation, the dynamic and thermodynamic characters and mechanism of adsorbing pollutants by granule bentonites. Granule bentonite (G-Bent) is compared with powder bentonite (P-Bent) in terms of adsorption efficiency, solid liquid separation facility and the desorption of modifier. The results list as follows:(1) the uptake of cationic surfactant on Na-bentonite is greater than that of nonionic Surfactant and anionic surfactant, and anionic surfactant showed hardly any adsorption. SDBS is adsorbed to Ca-bentonite mainly through precipitation interaction. It reaches a maximum at 1.5 Critical Micelle Concentration (CMC). Cetyl pyridinium chloride(CPC), in the low concerntration range, can enhance the uptake of TX-100 on bentonites, but inhibit the uptake when its concentration is high. The presence of SDBS can observably suppress the sorption of TX-100 on bentonites. The amount of CPC adsorbed on bentonite can be increased by NaCl. The removal rates of TX-100 can also be increased by NaCl from 56% to above 99% and is positively proportional to the concentration of NaCl. The sorption process of CPC on bentonite is exothermic reaction, while that of TX-100 is endothermic.(2) The removal rates of p-nitrophenol could be enhanced more than two times by quaternary ammonium cation surfactants with the long-chain alkyl . In treating waste water containing p-nitrophenol, the most economical dosage of surfactants correspondsto cation-exchange capacity (CEC) of bentonite. Compared with surfactant modified bentonite, "surfactant+bentonite" mixture of corresponding concentration is more effective in directly treating waster water containing p-nitrophenol and has advantages such as omitting the process of modifying bentonite, lower cost, and hardly no secondary pollution of surface active agent.(3) Using embed-immobilization technique, the optimal condition of bontonites's immobilization is found by variable control. Heavy metal is better removed by G-Bent than P-Bent when CEC loading capacity is relative high (>0.5CEC). In the range of 1.0-1.5CEC loading capacity, the removal rate of organic matters by G-Bent is corresponding to P-Bent, both larger than 90%. Overcoming the primary difficulty in solid liquid separation encounterd in the treating wastewater, G-Bent occupies the advantages of the easy solid liquid separation and centrifuge elimination. Besides, G-Bent has no secondary pollution as little surfactants and PVA desorption. The sorption of p-naphthol on bentonites can be well described by the Langmuir and Freundlich model. At examined P-naphthol concentrations(0~1000mg/L), the removal rate of P-naphthol by G-Bent is corresponding to P-Bent. Not sensitive to temperature, Sorption process of P-naphthol to G-Bent is endothermic reaction. The driving force of sorption is the decreasing of AG° and the increasing of AS0. G-Bent modified with 1.0CEC-1.5CEC loading capacity can effectively adsorb organic contaminants several times.
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