Department of Chemical Engineering, Indian Institute of Technology, Guwahati, Assam, 781039, India.
Department of Biosciences and Bioengineering, Indian Institute of Technology, Guwahati, Assam, 781039, India.
Environ Sci Pollut Res Int. 2020 Aug;27(22):28042-28052. doi: 10.1007/s11356-020-09155-8. Epub 2020 May 14.
The current study deals with the adsorption of hexavalent chromium using acid (HPO)-activated water caltrop (Trapa natans) shell (PWCS) using an up-flow packed bed column. Characteristics of breakthrough curve was obtained by investigating the effect of several operating parameters viz. inlet flow rate (2-6 mL/min), initial metal ion concentration (50-150 mg/L), and adsorbent's column bed height (1-3 cm). Elevated time of breakthrough curve was reported with elevated adsorbent bed height and vice versa with enhanced initial metal concentration and inlet flow rate of sorbate solution. Process design and breakthrough curves under varying conditions were predicted by applying column models like Thomas model, Adams-Bohart model, Yoon Nelson model, and bed depth service Time (BDST). Column behavior was better described by the BDST and Thomas model and simultaneously gave a good fit with the experimental data of breakthrough curves. The percentage removal for Cr(VI) from aqueous solution having pH 2 and temperature 303.15 K was observed to be 52.46%. The maximum adsorption capacity was found to be 87.31 mg/g according to the Thomas model. Conclusively, phosphoric acid-modified T. natans shell (PWCS) showed better sorption potential for of Cr(VI) species from simulated wastewater.
本研究采用上流式填充床柱，利用酸（HPO）活化的菱角壳（Trapa natans）（PWCS）吸附六价铬。通过考察几种操作参数（如入口流速（2-6mL/min）、初始金属离子浓度（50-150mg/L）和吸附剂床层高度（1-3cm）），获得了穿透曲线的特征。随着吸附剂床层高度的增加和初始金属浓度以及吸附质溶液入口流速的增加，穿透曲线的上升时间增加。通过应用柱模型（如 Thomas 模型、Adams-Bohart 模型、Yoon Nelson 模型和床层深度服务时间（BDST））对不同条件下的工艺设计和穿透曲线进行预测。BDST 和 Thomas 模型更好地描述了柱的行为，同时与穿透曲线的实验数据拟合良好。在 pH 值为 2 和温度为 303.15K 的水溶液中，Cr(VI)的去除率为 52.46%。根据 Thomas 模型，最大吸附容量为 87.31mg/g。结论是，磷酸化改性的菱角壳（PWCS）对模拟废水中的 Cr(VI)物种表现出更好的吸附潜力。
