Bisphenol A (BPA), an endocrine disrupting compound, is of concern because of its wide presence throughout the environment and its harmful effects. The present study aimed to prepare an eco-friendly, low-cost, and efficient adsorbent for removal of BPA from wastewater. A natural Tunisian clay was used as a raw material. First, the clay was purified and then modified with hexadecyltrimethylammonium bromide (HDTMA) using microwave heating. The optimal conditions for clay modification were as follows: activation ratio = 0.3:(g/g), solid/liquid ratio = 5%, and microwave heating condition (2:min, 100:W). The purified and modified clays, abbreviated as HP and HMH, respectively, were characterized by scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and nitrogen adsorption/desorption analysis (BET). Adsorption tests were conducted in a batch reactor process under various conditions. The tests showed that the BET specific surface area of HMH is considerably smaller than that of HP, whereas the basal spacing increased from 14.99 to 22.07 Å after modification, indicating the success of HP organophilization. The adsorption of BPA onto HMH was not affected by the pH of solution between 2 and 10 and only slightly by temperature variation from 23 to 50°C, but was affected significantly by the initial concentration of BPA, contact time, and organo-clay dose. At equilibrium, the data obtained were fitted to Langmuir and Freundlich models. The best fit was obtained by the Langmuir model with a maximum monolayer adsorption capacity of 217.39 mg/g at 23°C. The thermodynamic study suggested that the removal of BPA by HMH was spontaneous (Δ G < 0), exothermic (Δ H < 0), and favorable. The present study demonstrated that HMH synthesized from an abundant and cheap natural clay could be used successfully as a low-cost adsorbent for the removal of BPA from wastewater.

中文翻译：

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微波辐射下合成的 HDTMA-突尼斯粘土从水溶液中吸附双酚 A：参数和热力学研究

双酚 A (BPA) 是一种干扰内分泌的化合物，因其广泛存在于整个环境中并具有有害影响而受到关注。本研究旨在制备一种环保、低成本、高效的吸附剂，用于去除废水中的 BPA。使用天然突尼斯粘土作为原材料。首先，粘土被纯化，然后使用微波加热用十六烷基三甲基溴化铵（HDTMA）改性。粘土改性的最佳条件为：活化比=0.3:(g/g)，固液比=5%，微波加热条件(2:min，100:W)。通过扫描电子显微镜 (SEM)、傅里叶变换红外光谱 (FTIR)、X 射线衍射 (XRD)、和氮吸附/解吸分析（BET）。吸附试验在各种条件下在间歇反应器过程中进行。测试表明，HMH 的 BET 比表面积明显小于 HP，而修饰后的基础间距从 14.99 增加到 22.07 Å，表明 HP 有机化成功。BPA 在 HMH 上的吸附不受 2 到 10 之间溶液 pH 值的影响，仅受 23 到 50°C 温度变化的影响很小，但受 BPA 的初始浓度、接触时间和有机粘土剂量的影响显着. 在平衡时，获得的数据符合 Langmuir 和 Freundlich 模型。最佳拟合是通过 Langmuir 模型获得的，在 23°C 下最大单层吸附容量为 217.39 mg/g。热力学研究表明，HMH 对 BPA 的去除是自发的 (Δ G < 0)、放热 (Δ H < 0) 和有利的。本研究表明，由丰富且廉价的天然粘土合成的 HMH 可成功用作低成本吸附剂，用于去除废水中的 BPA。