Characterization Of Bentonites And Kaolinite Complex Modified With BS-12 And OTMA And Its Adsorption Of Cd²⁺ And Phenanthrene

Based on the high cation exchange capacity of the bentonite and the lower cation exchange capacity of the kaolinite as substrate, after modifying bentonite and kaolinite with a single amphoteric modifier, dodecyldimethylbetaine(BS-12), and mixture BS-12 with cationic modifier, eight alkyl trimethyl ammonium chloride(OTMA) for modified bentonite and kaolinite. The structure of amphoteric-cationic modified bentonites and kaolinites were characterized by the organic carbon contents, specific surface area, X-ray diffraction, FIRT,modification mechanism of modified agents were discussed from the micro level; the adsorption mechanisms of phenol, Cd2+ on amphoteric-cationic modified bentonites and kaolinites to find its affecting factors, i.e. temperature, pH and ionic strength were investigated, along with its adsorption isotherms and thermodynamics were also discussed in order to achieve a theoretical basis for the research and application of the pollutants adsorption on amphoteric-cationic modified adsorbents. The aim is to research and application of complex modifications by BS+OTMA for soil organic pollutants and heavy metals adsorbed simultaneously provide theoretical support, while providing a theoretical basis for organic modified clay mineral used in the field of environmental restoration.The conclusions of this paper are as follows:1)Each soil sample of bentonite on the effect of the adsorption of phenol、Cd2+ is much stronger than kaolinite in various soil samples;2) The adsorption effect of compound pollutants are weaker than the single pollution on the modified soil samples;3) The 100BS+100%OTMA of bentonite and the 100BS+25%OTMA of kaolinite on phenol adsorption effect is the best;4) The best effect of the adsorption of Cd2+ is the 100 BS of bentonite and kaolinite;5) In the range of this experiment,low pH and low ionic strength is beneficial to the adsorption of phenol,high pH and low ionic strength is advantageous to the adsorption of Cd2+,modified soil samples can relieve temperature effect.