The removal of salicylic acid (SA) and ibuprofen (IB) by sorption onto HDTMA-modified montmorillonite (HM) and zeolite (HZ) was investigated at pH 7. The single sorption data were fitted well by the Freundlich, Langmuir, Dubinin−Radushkevich (DR), and Polanyi−Dubinin−Manes (PDM) models (R² > 0.94). The sorption affinity of Freundlich and the maximum sorption capacity of Langmuir and PDM models of pharmaceuticals onto HM were consistently higher than that of HZ mainly owing to the higher organic carbon content. In addition, the K_F, q_mL, and q_m values were in the order of IB > SA owing to higher hydrophobicity and molar volume. Since the predominant speciation of SA and IB is anionic at pH 7 (>pKa), sorption onto HM occurs mainly by the two-dimensional surface adsorption onto the pseudo-organic medium in the HM, whereas the interaction of anionic pharmaceuticals with the positively charged “head” of HDTMA is responsible for HZ. Sorption isotherms were fitted well by the PDM model, which indicated that pore-filling was one of the dominating sorption mechanisms. The extended Langmuir model, modified Langmuir competitive model, and ideal adsorbed solution theory employed with Freundlich and Langmuir sorption models were applied to predict binary sorption. The effect of competition between the solutes was clearly evident in the characteristic curves; the maximum sorbed volume (q_v.m) was reduced, and the sorbed volume (q_v) had a wider distribution toward the sorption potential density.

中文翻译：

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十六烷基三甲基铵改性蒙脱土和沸石去除水杨酸和布洛芬

在pH 7下研究了通过吸附到HDTMA改性的蒙脱石（HM）和沸石（HZ）上去除水杨酸（SA）和布洛芬（IB）的情况。Freundlich，Langmuir，Dubinin-Radushkevich拟合得很好。 （DR）和Polanyi-Dubinin-Manes（PDM）模型（R ² > 0.94）。Freundlich的吸附亲和力以及Langmuir和PDM模型对HM的最大吸附能力始终高于HZ，这主要是由于有机碳含量较高。此外，K _F，q _mL和q _m由于较高的疏水性和摩尔体积，所以其值按IB> SA的顺序排列。由于SA和IB的主要形态是在pH 7（> pKa）时为阴离子，因此HM的吸附主要是通过二维表面吸附到HM中的假有机介质上，而阴离子药物与带正电荷的相互作用HDTMA的“负责人”负责HZ。PDM模型很好地拟合了吸附等温线，这表明孔填充是主要的吸附机理之一。将扩展的Langmuir模型，改良的Langmuir竞争模型以及与Freundlich和Langmuir吸附模型一起使用的理想吸附溶液理论应用于预测二元吸附。在特性曲线中，溶质之间竞争的影响显而易见。最大吸附量（q _v.m）减小，并且吸附体积（q _v）朝着吸附电位密度具有较宽的分布。