School of Civil and Environmental Engineering, 50 Nanyang Avenue #N1-1b-35, Nanyang Technological University, Singapore 639798, Singapore.
Water Res. 2010 Apr;44(8):2654-62. doi: 10.1016/j.watres.2010.01.038. Epub 2010 Feb 2.
Perfluorooctane sulfonate (PFOS) is an emergent contaminant of substantial environmental concerns, yet very limited information has been available on PFOS adsorption onto mineral surfaces. PFOS adsorption onto goethite and silica was investigated by batch adsorption experiments under various solution compositions. Adsorption onto silica was only marginally affected by pH, ionic strength, and calcium concentration, likely due to the dominance of non-electrostatic interactions. In contrast, PFOS uptake by goethite increased significantly at high [H+] and [Ca2+], which was likely due to enhanced electrostatic attraction between the negatively charged PFOS molecules and positively charged goethite surface. The effect of pH was less significant at high ionic strength, likely due to electrical double layer compression. PFOS uptake was reduced at higher ionic strength for a strongly positively charged goethite surface (pH 3), while it increased for a weakly charged surface (pH 7 and 9), which could be attributed to the competition between PFOS-surface electrostatic attraction and PFOS-PFOS electrostatic repulsion. A conceptual model that captures PFOS-surface and PFOS-PFOS electrostatic interactions as well as non-electrostatic interaction was also formulated to understand the effect of solution chemistry on PFOS adsorption onto goethite and silica surfaces.
全氟辛烷磺酸（PFOS）是一种具有重要环境意义的新兴污染物，但关于其在矿物表面吸附的信息非常有限。通过在不同溶液组成下进行批吸附实验，研究了 PFOS 在针铁矿和硅石上的吸附。硅石对 PFOS 的吸附受 pH 值、离子强度和钙离子浓度的影响很小，可能是由于非静电相互作用占主导地位。相比之下，在高[H+]和[Ca2+]条件下，针铁矿对 PFOS 的摄取显著增加，这可能是由于带负电荷的 PFOS 分子与带正电荷的针铁矿表面之间增强的静电引力所致。在高离子强度下，pH 值的影响较小，可能是由于双电层压缩所致。对于带强正电荷的针铁矿表面（pH 3），离子强度增加会降低 PFOS 的摄取量，而对于带弱电荷的表面（pH 7 和 9），则会增加 PFOS 的摄取量，这可能归因于 PFOS-表面静电引力和 PFOS-PFOS 静电斥力之间的竞争。还制定了一个概念模型，以捕捉 PFOS-表面和 PFOS-PFOS 静电相互作用以及非静电相互作用，以了解溶液化学对 PFOS 在针铁矿和硅石表面吸附的影响。
