Organic Bentonite On The Adsorption Characteristics Of Organic Pollutants In Water And Its Stability

Four kinds of organic bentonite were synthesized by using surface active agent--- CTMAB, DTMAB, DPB, CPB, on the basis of fully understanding characters of bentonite. We want to know how do organic molecules arrayed between the bentonite levels, as well as, how does it affect the space of different levels. Simulate experiments were carried out to study how does surface active agent and its amount influence synthesized bentonite's capability of adsorbing organic pollutant, such as p-nitrophenol, the aniline, chloral. Environmental factors were also included. Stability of different kinds of organic bentonite were also studied from the view of environment safety. The main results were as follows:(1) through the organic modification, the surfactant insert into the interlayer and increase the interlayer space and organic content. the interlayer space and organic content of long carbon chain surfactant modification organic-bentonite is bigger than short carbon chain surfactant modification organic-bentonite. the surfactant arrangement model became complex with the increasing of carbon chain length and amount of surfanctant. and the change of arrangement of surfactant can be summarized as the following :lateral monolayerâ†'lateral bilayerâ†'paraffin-type monolayerâ†'pseudotrilayer.(2)It showed a direct correlation between the removal rate of phenol to organic-bentonite with carbon chain length of surfactant. Removal rate of phenol to organic-betonite was modified by long chain surfactant is higher than that modified by short chain surfactant. Removal rate of phenol to organic-bentonite modified by aliphatic surfactant is higher than that modified by pyridyl surfactant. Under the neutral pH condition, the removal rate to the phenol, the aniline and p-nitrophenol of organic-bentonite is higher than than under the acid or alkaline condition. Under the same concentration, the adsorption content sequence to three contaminant of bentonite is p-nitrophenol > phenol > aniline, The results showed that the adsorption of organic-bentonite to P-nitrophenol, phenol and aniline was distinct and relevant to octanol-water partition coefficient of organic compounds themselves. the removal rare to chloral of CTAMB modification organic bentonite under the alkaline condition has a distinct enhancement compared to the neutral condition. the regression result of adsorption property to contaminant of organic-bentonite showed that the adsorption of chloral by organobentonite could be well described by Freundlich isotherms adsorption model. the COD and chromaticity removal rate of papermaking waster by organic-bentonite increased with increasing amount of surfactant.(3)Regarding the stability of organic-bentonite modified with different cationic surfactants. Stability of organic-bentonites modified by CTMAB and CPB is better, but stability of organic-bentonires modified by DTMAB and DPB is worse. CaCl2 and NaCl have a more tremendous influence on stability of organic-bentonite that contanin 12 carbon atoms alkyl chain, but the influence is little to orgnic-bentonite contain 16 carbon atoms alkyl chain. Organic-bentonites showed high resistibility to shaking time, shaking intensity and temperature, but pH value can effect the stability of organic-bentonite strongly.(4) Speaking of the stability of organic-bentonites modified with different amount of surfactant, the stability of organic-bentonites declined with increasing amount of cationic surfactant under the same condition. When the amount of cationic surfactant is less than or equal to bentonite CEC, the organic-bentonite is quite stable. The stability of organic-bentonite decreased, when the quantity of cationic surfactant is higher than the bentonite CEC. Shaking time, shaking intensity and temperature have almost nothing effect on stability of organic-bentonite. The ultrasonic wave and the pH may enable to reduce the stability of organic bentonite stability of three kinds of organic-bentonite increased with increasing concentration of NaCl and CaCl2, especially enhances the stability of organic-bentonite modified by the high amount of cationic surfactant.