Department of Chemical Engineering, National Institute of Technology Calicut, Kozhikode, Kerala 673601, India E-mail:
Water Sci Technol. 2020 Aug;82(3):468-480. doi: 10.2166/wst.2020.346.
In this work, a biosorbent was prepared by the ultrasound-acid treatment of Merremia vitifolia plant and tested for the removal of 2,4-dichlorophenoxyacetic acid (2,4-D), a phenoxy herbicide. Optimal values of five batch biosorption parameters namely stirring speed, contact time, biosorbent dosage, initial pH and initial adsorbate concentration were experimentally obtained in sequential manner for an enhanced biosorption capacity. The kinetics of the biosorption of 2,4-D were best described by the pseudo first order kinetic model (R = 0.99) and the biosorption equilibrium data were successfully fitted to the Langmuir adsorption isotherm (R = 0.99) with a maximum biosorption capacity of 66.93 mg g. The mechanism of biosorption was investigated using two intraparticle diffusion models (Weber and Boyd), Dubinin-Radushkevich isotherm model and electrostatic interactions. The presence of intraparticle and film diffusion limitations for the biosorption was confirmed along with the physical and chemical nature of the biosorption. The thermodynamic parameters of the biosorption were calculated using the equilibrium data obtained at four different temperatures. The entropy change for biosorption was found to be negative indicating the decreased randomness at the interface. Desorption studies were carried out using different solvents and the percentages of desorption were compared.
在这项工作中，通过超声-酸处理黧蒴锥植物制备了一种生物吸附剂，并将其用于去除 2,4-二氯苯氧乙酸（2,4-D），一种苯氧类除草剂。以增强生物吸附能力的方式依次实验获得了五个批次生物吸附参数（搅拌速度、接触时间、生物吸附剂用量、初始 pH 值和初始吸附质浓度）的最佳值。2,4-D 的生物吸附动力学最好由拟一级动力学模型（R = 0.99）描述，并且生物吸附平衡数据成功拟合到 Langmuir 吸附等温线（R = 0.99），最大生物吸附容量为 66.93mg g。使用两种内扩散模型（Weber 和 Boyd）、Dubinin-Radushkevich 等温线模型和静电相互作用研究了生物吸附的机理。确认了生物吸附存在内扩散和膜扩散限制，以及生物吸附的物理和化学性质。使用在四个不同温度下获得的平衡数据计算了生物吸附的热力学参数。发现生物吸附的熵变化为负，表明界面处的随机性降低。使用不同的溶剂进行了解吸研究，并比较了解吸的百分比。
