Adsorption of volatile organic compounds onto porous clay hetero structures based on spent organobentonites

作者：Zhu LZ^*; Tian SL; Shi Y

来源：Clays and Clay Minerals, 2005, 53(2): 123-136.

DOI：10.1346/CCMN.2005.0530202

• adsorption
• organobentonite
• porous clay heterostructures
• VOC

Model spent cetyltrimethylamrnoniurn bromide (CTMAB)-bentonite, and cetyl pyridiniurn chloride (CPC)-bentonite used for sorbing p-nitrophenol (PNP) from wastewater, as well as virgin CTMAB-bentonite and CPC-bentonite, were employed as the starting materials to prepare porous clay heterostructures (PCHs). The BET surface areas and total pore volumes of the PCHs based on these spent and virgin organobentonites (PNP-CTMAB-PCH, CTMAB-PCH, PNP-CPC-PCH and CPC-PCH) are 661.5 m(2)/g and 0.25 cm(3)/g, 690.4 m(2)/g and 0.27 cm(3)/g, 506.3 m(2)/g and 0.30 cm(3)/g, and 525.4 m(2)/g and 0.30 cm(3)/g respectively. These values approximate those of activated carbon (AC), at 731.4 m(2)/g and 0.23 cm(3)/g. and are much larger than those of bentonite and CTMAB-bentonite, at 60.9 m(2)/g and 0.12 cm(3)/g, and 3.7 m/g(2) and 0.0055 m(2)/g, respectively. The PCHs have slightly higher adsorption capacities for benzene and CCl4 than AC at higher relative pressures despite their comparatively lower benzene and CCl4 adsorption capacity at lower relative pressures. The existence of PNP in organobentonites also enhances the volatile organic compounds (VOCs) adsorption capacity of PCI-Is at lower adsorbate concentrations, although some adsorption capacity is lost at higher concentrations. The hydrophobicity order of the adsorbents is: CTMAB-bentonite > AC > PCHs > bentonite. The micro- to rnesoporous pore sizes, superior VOC adsorption properties, thermal stability to 750 degrees C and hydrophobicity and negligible influences of PNP on PCHs make spent PNP-containing organobentonites ideal starting materials for synthesis of PCHs and especially attractive adsorbents for VOC sorption control.

• 出版日期2005-4
• 单位浙江大学