School of Chemical Engineering, Jimma Institute of Technology, Jimma University, P.O. Box 378, Jimma, Oromia, Ethiopia.
Faculty of Agricultural and Environmental Sciences, University of Rostock, Justus-Von-Liebig-Weg 6, 18059 Rostock, Germany.
Molecules. 2021 Feb 12;26(4):977. doi: 10.3390/molecules26040977.
Consumption of drinking water with a high concentration of fluoride (>1.5 mg/L) causes detrimental health problems and is a challenging issue in various regions around the globe. In this study, a continuous fixed-bed column adsorption system was employed for defluoridation of water using volcanic rocks, virgin pumice (VPum) and virgin scoria (VSco), as adsorbents. The XRD, SEM, FTIR, BET, XRF, ICP-OES, and pH Point of Zero Charges (pH) analysis were performed for both adsorbents to elucidate the adsorption mechanisms and the suitability for fluoride removal. The effects of particle size of adsorbents, solution pH, and flow rate on the adsorption performance of the column were assessed at room temperature, constant initial concentration, and bed depth. The maximum removal capacity of 110 mg/kg for VPum and 22 mg/kg for VSco were achieved at particle sizes of 0.075-0.425 mm and <0.075 mm, respectively, at a low solution pH (2.00) and flow rate (1.25 mL/min). The fluoride breakthrough occurred late and the treated water volume was higher at a low pH and flow rate for both adsorbents. The Thomas and Adams-Bohart models were utilized and fitted well with the experimental kinetic data and the entire breakthrough curves for both adsorbents. Overall, the results revealed that the developed column is effective in handling water containing excess fluoride. Additional testing of the adsorbents including regeneration options is, however, required to confirm that the defluoridation of groundwater employing volcanic rocks is a safe and sustainable method.
饮用水中高浓度氟化物（>1.5mg/L）的摄入会对健康造成有害影响，这是全球各地区面临的一个挑战。在这项研究中，采用连续固定床柱吸附系统，使用火山岩、原火山灰（VPum）和原火山渣（VSco）作为吸附剂，对水进行除氟。对两种吸附剂进行了 XRD、SEM、FTIR、BET、XRF、ICP-OES 和 pH 零电荷点（pH）分析，以阐明吸附机制和去除氟化物的适宜性。在室温下、恒定初始浓度和床层深度下，评估了吸附剂粒径、溶液 pH 值和流速对柱吸附性能的影响。VPum 的最大去除容量为 110mg/kg，VSco 的最大去除容量为 22mg/kg，分别在粒径为 0.075-0.425mm 和<0.075mm 时、溶液 pH 值（2.00）和流速（1.25mL/min）较低时达到。两种吸附剂的氟化物穿透时间都较晚，在较低 pH 值和流速下，处理的水量更高。托马斯和亚当斯-博哈特模型被用来拟合实验动力学数据和两种吸附剂的整个穿透曲线，拟合效果都很好。总的来说，结果表明，所开发的柱在处理含有过量氟化物的水方面是有效的。然而，需要对吸附剂进行更多的测试，包括再生选项，以确认采用火山岩对地下水进行除氟是一种安全且可持续的方法。
