- Yi Li: Key Laboratory of Integrated Regulation and Resource Development of Shallow Lakes, Ministry of Education, College of Environment, Hohai University, Xikang Road #1, Nanjing, 210098, People's Republic of China, envly@hhu.edu.cn.
Bentonite was modified with cationic surfactant hexadecyl trimethyl ammonium bromide (HTAB) as landfill liner to retard the transportation of bisphenol A (BPA) for the first time. The modification was confirmed to form a lateral bi-layer in the interlayer space of bentonite by scanning electron microscope, X-ray diffraction, and Fourier transform infrared spectroscopy. The introduction of HTAB into the internal position of bentonite led to an increased interlayer space of bentonite from 15.0 to 20.9 Å and a higher sorption affinity for BPA (10.449 mg/g of HTAB-bentonite and 3.413 mg/g of raw bentonite). According to the Freundlich model, the maximum adsorption capacity of the HTAB-bentonite was found to be 0.410 mg/g. The sorption capacity of raw bentonite and HTAB-bentonite both decreased at alkaline conditions. Although the hydraulic conductivity of HTAB-bentonite was higher than that of raw bentonite, results of laboratory permeability and column tests indicated that HTAB-bentonite obviously extended the BPA breakthrough time by 43.4 %. The properties of the HTAB-bentonite revealed its notable advantages as components of landfill liners material to retain BPA in leachate.