title: Pretreatment effects on the sorption of Cr(VI) onto surfactant-modified zeolite: Mechanism analysis.
abstract: Adsorption of Cr(VI) onto different pretreated zeolites modified with cetylpyridinium chloride (CPC) is investigated using batch studies, Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) measurements and scanning electron microscopy (SEM). The results indicate that acidification after alkalization is the most effective pretreatment method, and only alkalization would significantly reduce the sorption capability. This behavior is due to the precipitates, such as CaCO3 and MgCO3, generated after alkalization on zeolite surface interfere the formation of the CPC bilayer, which provides active sites for sorbing Cr(VI). The schematic of the adsorption mechanism is presented. The results indicate that developing a better understanding of the influence of different pretreatments is quite helpful and suggest that the content of Ca/Mg/Fe could be a good indication of the effectiveness of preprocessing.
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Wenzhe
authors.initials: W
authors.lastname: Song
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China. Electronic address: eesshth@mail.sysu.edu.cn.
authors.forename: Taihong
authors.initials: T
authors.lastname: Shi
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Di
authors.initials: D
authors.lastname: Yang
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Jinpeng
authors.initials: J
authors.lastname: Ye
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: School of Environmental Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, PR China.
authors.forename: Yuxiang
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000327:Adsorption; D002119:Calcium Carbonate / Q000737:chemistry; D002594:Cetylpyridinium / Q000737:chemistry; D002857:Chromium / Q000737:chemistry*; D008274:Magnesium / Q000737:chemistry; D008855:Microscopy, Electron, Scanning; D017550:Spectroscopy, Fourier Transform Infrared; D013499:Surface Properties; D013501:Surface-Active Agents / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000737:chemistry; D014961:X-Ray Diffraction; D017641:Zeolites / Q000737:chemistry*
chemical_list: D013501:Surface-Active Agents; D014874:Water Pollutants, Chemical; C005479:magnesium carbonate; D002857:Chromium; D017641:Zeolites; C074702:chromium hexavalent ion; D002594:Cetylpyridinium; D002119:Calcium Carbonate; D008274:Magnesium
keywords: Adsorption; Chromate; Pretreatment; Surfactant; Zeolite