School of Environment, Beijing Normal University, State Key Laboratory of Water Environment Simulation, Beijing 100875, China.
Chemosphere. 2011 May;83(10):1313-9. doi: 10.1016/j.chemosphere.2011.04.018. Epub 2011 Apr 30.
Perfluorooctane sulfonate (PFOS), as one of emerging contaminants, has been attracting increasing concerns in recent years. Sorption of PFOS by maize straw- and willow-derived chars (M400 and W400), maize straw-origin ash (MA) as well as three carbon nanotubes (CNTs) was studied in this work. The sorption kinetics of PFOS by the six adsorbents was well fitted by the pseudo-second-order model. CNTs reached equilibrium in 2h, much faster than those by chars (384 h) and ash (48 h). According to the sorption isotherms, both single-walled carbon nanotubes (SWCNT) and MA had high sorption capacities (over 700 mg g(-1)), while the two chars had low sorption capacities (below 170 mg g(-1)) caused by their small BET surface area. In the case of MA, due to its positively charged surface, both hydrophobic interaction and electrostatic attraction involved in the sorption, and the formation of hemi-micelles further favored the sorption. This study suggested that SWCNT and MA were effective adsorbents for PFOS removal from water. Compared to SWCNT, MA is low cost and easy to obtain, so it could be a preferred adsorbent for PFOS removal.
全氟辛烷磺酸（PFOS）作为一种新兴污染物，近年来受到越来越多的关注。本研究考察了玉米秸秆和柳树衍生炭（M400 和 W400）、玉米秸秆灰（MA）以及三种碳纳米管（CNTs）对 PFOS 的吸附。六种吸附剂对 PFOS 的吸附动力学均很好地符合拟二级动力学模型。CNTs 在 2h 内达到平衡，远快于炭（384h）和灰（48h）。根据吸附等温线，单壁碳纳米管（SWCNT）和 MA 具有很高的吸附容量（超过 700mg/g），而两种炭由于其比表面积小，吸附容量较低（低于 170mg/g）。对于 MA，由于其带正电荷的表面，吸附过程中涉及疏水相互作用和静电吸引，并且半胶束的形成进一步有利于吸附。本研究表明，SWCNT 和 MA 是从水中去除 PFOS 的有效吸附剂。与 SWCNT 相比，MA 成本低、易于获得，因此可能是去除 PFOS 的首选吸附剂。
