Abstract: The surfactant-modified organobentonites with chelating ligands, IMB-CTMA-Am, were synthesized, where IMB refers to natural bentonite obtained from Inner Mongolia of China, CTMAB refers to quaternary ammonium cation surfactant of cetyltrimethylammonium bromide, and Am refers to the chelating ligands, respectively. The adsorbent samples were characterized by X-ray diffraction(XRD), thermogravimetric and differential thermal(TG-DTA) analyses, specific surface area(N₂-BET) measurements, and elemental analysis. The results indicated that CTMA⁺ and Am intercalated into the lamellae of bentonites successfully. The adsorption experiments showed that IMB-CTMA-Am could effectively adsorb organic pollutant p-nitrophenol(PNP) and heavy metal ion Pb²⁺ in waste water system simultaneously. The adsorption capabilities of IMB-CTMA-Am are greater than natural bentonite IMB and modified bentonite IMB-CTMA. Fourier transform infrared(FTIR) spectrum study revealed that the N—H vibrational frequency of IMB-CTMA-Am was downshifted after Pb²⁺ adsorption, which demonstrates the formation of a metal complex between metal ion Pb²⁺ and Am in the interlayers of the modified bentonites. The adsorption capacity of Pb²⁺ onto IMB-CTMA-Am agrees with the stability constant of the complex formed.

Key words: Modified bentonite, Simultaneous adsorption, Quaternary ammonium cation, p-Nitrophenol, Heavymetal