Mokokwe Gobusaone, Letshwenyo Moatlhodi Wise
Botswana International University of Science and Technology, Faculty of Engineering and Technology, Botswana.
Department of Civil and Environmental Engineering, Private Bag 16, Palapye, Botswana.
Heliyon. 2022 Jul 16;8(7):e09963. doi: 10.1016/j.heliyon.2022.e09963. eCollection 2022 Jul.
The adsorption of copper, iron and nickel ions from an aqueous solution using Makoro granite clay brick waste through batch and fixed - bed column modes was investigated. The adsorbent was characterised using X-Ray Fluorescence, X-Ray Diffraction (XRD), Thermogravimetric Analysis, and Scanning Electron Microscopy (SEM). XRD results revealed crystalline peaks of Quartz (51.28 %) and mullite (23.40%) in fresh and loaded adsorbent with unnotable changes before and after adsorption. SEM images indicate the presence of micro pores and irregularly distributed surfaces. Batch kinetic maximum adsorption capacities for iron, copper, and nickel are 7.60, 6.70 and 6.20 mg g media respectively with 60 min as the optimum time. The maximum adsorption capacities at adsorbent dosage of 5 g L were 10.0, 7.60 and 7.20 mg L for iron, copper and nickel ions. The corresponding adsorption capabilities from the fixed-bed column reactor were 2.23, 2.22 and 0.74 mg g media respectively. The thermodynamics parameters of enthalpy change (ΔH) were 5.21, 9.32 and 5.22 kJ mol respectively for Copper, iron and nickel ions and the corresponding entropy change (ΔS) were -0.04, -0.05 and -0.03 kJmolKrespectively and the process being non-spontaneous and exothermic. Thomas and Yoon-Nelson models yielded similar low coefficient of determination (R) values (0.06 and 0.07) for copper and iron ions. Further investigations such as the use of real wastewater, competition of anions and further media characterisation and modifications are recommended.
研究了利用马科罗花岗岩粘土砖废料通过间歇和固定床柱模式从水溶液中吸附铜、铁和镍离子。使用X射线荧光、X射线衍射（XRD）、热重分析和扫描电子显微镜（SEM）对吸附剂进行了表征。XRD结果显示，新鲜和负载后的吸附剂中石英（51.28%）和莫来石（23.40%）的结晶峰在吸附前后变化不明显。SEM图像表明存在微孔和表面分布不规则的情况。铁、铜和镍的间歇动力学最大吸附容量分别为7.60、6.70和6.20 mg/g介质，最佳时间为60分钟。吸附剂用量为5 g/L时，铁、铜和镍离子的最大吸附容量分别为10.0、7.60和7.20 mg/L。固定床柱反应器的相应吸附能力分别为2.23、2.22和0.74 mg/g介质。铜、铁和镍离子的焓变（ΔH）热力学参数分别为5.21、9.32和5.22 kJ/mol，相应的熵变（ΔS）分别为-0.04、-0.05和-0.03 kJ/(mol·K)，该过程为非自发且放热过程。托马斯模型和尹-尼尔森模型对铜和铁离子的测定系数（R）值较低且相似（分别为0.06和0.07）。建议进一步开展研究，如使用实际废水、阴离子竞争以及进一步的介质表征和改性。
