Abstract

Four cationic surfactants with various length and number of long alkyl chains such as dodecyltrimethylammonium, tetradecyltrimethyl-ammonium, hexadecyltrimethylammonium and didodecyldimethyl-ammonium were intercalated at different concentrations into two natural clays from Burkina Faso via solid-state reaction. Each organoclay was used to explore bisphenol A (BPA) removal from water. Various factors including adsorbent dose, agitation time, concentration, surfactant loading levels, pH and temperature were evaluated. Further, pseudo-first and pseudo-second kinetics, Langmuir and Freundlich isotherms and thermodynamics of adsorption onto organoclays were investigated. The adsorption mechanism was perfectly described by pseudo-second-order kinetic model and Langmuir isotherm. Spontaneous and exothermic processes were associated with BPA removal. This study showed that both physisorption and chemisorption are involved in BPA adsorption. Adsorption capacities ranging from 88 to 127 mg/g were observed at ambient temperature and acidic environment. The ranking of organoclays sorption capacities depends on the surfactant loading level. The pH effect on the adsorption showed a remarkable decrease in the quantity of BPA removed when pH ≥ 10. The BPA amount adsorbed onto the organoclays was not varying significantly for pH < 10. Organoclays prepared via solid-state surfactant intercalation are as effective adsorbents for BPA removal from water as those prepared in aqueous solution through cation exchange.

摘要

具有各种长度和长链烷基如十二烷基，十四烷基铵，十六烷基和didodecyldimethyl铵的数目四阳离子表面活性剂在不同浓度的嵌入成两个天然粘土来自布基纳法索经由固态反应。每种有机粘土都用于探索从水中去除双酚A（BPA）的方法。评价了各种因素，包括吸附剂剂量，搅拌时间，浓度，表面活性剂负载量，pH和温度。此外，还研究了伪第一和伪第二动力学，Langmuir和Freundlich等温线以及吸附到有机粘土上的热力学。拟二级动力学模型和Langmuir等温线完美地描述了吸附机理。自发和放热过程与BPA的去除有关。这项研究表明，物理吸附和化学吸附均与BPA吸附有关。在环境温度和酸性环境下观察到的吸附容量为88至127 mg / g。有机粘土吸附能力的等级取决于表面活性剂的负载量。通过固态表面活性剂插层，与从水溶液中通过阳离子交换制得的BPA一样，是从水中去除BPA的有效吸附剂。