Mu'azu Nuhu Dalhat, Essa Mohammed Hussain, Lukman Salihu
Department of Environmental Engineering, University of Dammam, Dammam 31451, Saudi Arabia E-mail:
Department of Civil and Environmental Engineering, King Fahd University of Petroleum and Minerals, Dhahran 31262, Saudi Arabia.
Water Sci Technol. 2017 Oct;76(7-8):2213-2221. doi: 10.2166/wst.2017.395.
Multicomponent adsorption of Cd, Cr, Cu, Pb and Zn onto date palm pits based granular activated carbon (GAC) augmented with highly active natural clay at different proportion was investigated. The effects of the initial pH and the adsorbents mixed ratio on the removal selectivity sequence of the metals evaluated. Batch adsorption experiments were undertaken at initial pH 2, 6 and 12. At initial pH 2, both the percent removal and the metals adsorptive capacity decreased with increasing GAC to clay ratio (from 0 to 1) with the percentage removal of Cd, Zn and Cr ions dropping from 68, 81, 100% to 43, 57 and 70%, respectively. At both pH 6 and 12, the percentage removals and adsorption capacities of all the heavy metal ions are higher than at pH 2. Selectivity sequences for pH 2, 6 and 12 followed the order Pb > Cr > Cu > Zn > Cd; Pb > Cr > Cu > Cd > Zn and Cd > Cr > Cu > Pb > Zn, respectively. The adsorption trends were analyzed in relation to point of zero charge and ξ-potential and the metals ions speciation at different pH. These results will help better understand the feasibility of augmenting GAC with natural clay minerals during fixed bed column test which is more beneficial for practical industrial applications.
研究了不同比例添加高活性天然粘土的椰枣核基颗粒活性炭（GAC）对镉、铬、铜、铅和锌的多组分吸附。评估了初始pH值和吸附剂混合比例对金属去除选择性顺序的影响。在初始pH值为2、6和12的条件下进行了批量吸附实验。在初始pH值为2时，随着GAC与粘土比例的增加（从0到1），去除率和金属吸附容量均下降，镉、锌和铬离子的去除率分别从68%、81%、100%降至43%、57%和70%。在pH值为6和12时，所有重金属离子的去除率和吸附容量均高于pH值为2时。pH值为2、6和12时的选择性顺序分别为铅>铬>铜>锌>镉；铅>铬>铜>镉>锌；镉>铬>铜>铅>锌。根据零电荷点、ξ电位和不同pH值下金属离子的形态分析了吸附趋势。这些结果将有助于更好地理解在固定床柱试验中用天然粘土矿物增强GAC的可行性，这对实际工业应用更有益。
