Department of Chemical Engineering, University of Engineering and Technology, Lahore 54890, Pakistan E-mail:
Department of Chemistry, King Fahd University of Petroleum and Minerals, Dhahran 31261, Saudi Arabia.
Water Sci Technol. 2022 Oct;86(8):1969-1980. doi: 10.2166/wst.2022.324.
A surfactant-modified coal fly ash was developed as a multifunctional adsorbent for the removal of organic pollutants from wastewater. Sodium dodecyl sulfate (SDS) was used to modify the surface of coal fly ash (CFA). The modified CFA was characterized using scanning electron microscopy (SEM), surface porosity analyzer, thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopy. The results showed that loading CFA with SDS not only improved the functionality and surface morphology of the raw ash for the adsorption of organic pollutants, but also enhanced its thermal stability. The efficiency of the modified fly ash was tested in terms of removal of two non-polar organic pollutants namely chlorobenzene (CB) and nitrobenzene (NB) from aqueous phase. The maximum uptake capacity of chlorobenzene and nitrobenzene with SDS-modified coal fly ash (SCFA) was 225 mg/g and 90 mg/g, respectively. The kinetic analysis was done by controlled kinetic models, i.e., pseudo first and second order kinetic models. The results showed that adsorption of CB and NB onto SCFA followed a pseudo second order kinetic model. The adsorption of chlorobenzene was exothermic over the modified adsorbent while nitrobenzene showed an endothermic behavior. The isotherm analysis depicted the multilayer adsorption of both pollutants onto the surface of the surfactant modified adsorbent. This work has shown that surface modification using surfactants can be a viable option to enhance the adsorption capacity of fly ash for pollutants removal.
一种表面活性剂改性的粉煤灰被开发为一种多功能吸附剂，用于去除废水中的有机污染物。十二烷基硫酸钠（SDS）被用来修饰粉煤灰（CFA）的表面。采用扫描电子显微镜（SEM）、表面孔隙率分析仪、热重分析（TGA）和傅里叶变换红外（FTIR）光谱对改性 CFA 进行了表征。结果表明，负载 SDS 的 CFA 不仅提高了原始灰分的功能和表面形态，用于吸附有机污染物，而且提高了其热稳定性。通过从水相中去除两种非极性有机污染物氯苯（CB）和硝基苯（NB）来测试改性粉煤灰的效率。SDS 改性粉煤灰（SCFA）对氯苯和硝基苯的最大吸附容量分别为 225mg/g 和 90mg/g。通过控制动力学模型，即拟一级和拟二级动力学模型进行动力学分析。结果表明，CB 和 NB 吸附到 SCFA 上遵循拟二级动力学模型。氯苯在改性吸附剂上的吸附是放热的，而硝基苯则表现出吸热行为。等温线分析描述了两种污染物在表面活性剂改性吸附剂上的多层吸附。这项工作表明，表面活性剂的表面修饰是一种可行的选择，可以提高粉煤灰对污染物去除的吸附能力。
