Alorabi Ali Q, Hassan Mallick Shamshi, Alam Mohammad Mahboob, Zabin Sami A, Alsenani Nawaf I, Baghdadi Neazar Essam
Chemistry Department, Faculty of Science, Albaha University, P.O. Box 1988, Albaha 65799, Saudi Arabia.
Center of Nanotechnology, King Abdul Aziz University, P.O. Box 80216, Jeddah 21589, Saudi Arabia.
Nanomaterials (Basel). 2021 Oct 21;11(11):2789. doi: 10.3390/nano11112789.
This investigation aimed at evaluating the efficiency of micro and nanoclays as a low-cost material for the removal of crystal violet (CV) dye from an aqueous solution. The impacts of various factors (contact time, pH, adsorbent dosage, temperature, initial dye concentration) on the adsorption process have been taken into consideration. Six micro and nanoclay samples were obtained by treating clay materials collected from different locations in the Albaha region, Saudi Arabia. Out of the six tested micro and nanoclays materials, two (NCQ1 and NCQ3) were selected based on the highest adsorption efficiency for complete experimentation. The morphology and structure of the selected micro and nanoclay adsorbents were characterized by various techniques: SEM-EDX, FTIR, XRF, XRD, and ICP-MS. The XRF showed that the main oxides of both nanoclays were SiO, AlO, FeO, KO, CaO, and MgO, and the rest were impurities. All the parameters affecting the adsorption of CV dye were optimized in a batch system, and the optimized working conditions were an equilibrium time of 120 min, a dose of 30 mg, a temperature of 25 °C, and an initial CV concentration of 400 mg/L. The equilibrium data were tested using nonlinear isotherm and kinetic models, which showed that the Freundlich isotherm and pseudo-second-order kinetics gave the best fit with the experimental data, indicating a physico-chemical interaction occurred between the CV dye and both selected micro and nanoclay surfaces. The maximum adsorption capacities of NCQ1 and NCQ3 adsorbents were 206.73 and 203.66 mg/g, respectively, at 25 °C. The thermodynamic factors revealed that the CV dye adsorption of both micro and nanoclays was spontaneous and showed an exothermic process. Therefore, the examined natural micro and nanoclays adsorbents are promising effective adsorbents for the elimination of CV dye from an aqueous environment.
本研究旨在评估微米和纳米粘土作为一种低成本材料从水溶液中去除结晶紫（CV）染料的效率。考虑了各种因素（接触时间、pH值、吸附剂用量、温度、初始染料浓度）对吸附过程的影响。通过处理从沙特阿拉伯阿尔巴哈地区不同地点采集的粘土材料，获得了六种微米和纳米粘土样品。在六种测试的微米和纳米粘土材料中，基于最高吸附效率选择了两种（NCQ1和NCQ3）进行完整实验。通过扫描电子显微镜-能谱仪（SEM-EDX）、傅里叶变换红外光谱仪（FTIR）、X射线荧光光谱仪（XRF）、X射线衍射仪（XRD）和电感耦合等离子体质谱仪（ICP-MS）等多种技术对所选微米和纳米粘土吸附剂的形态和结构进行了表征。XRF分析表明，两种纳米粘土的主要氧化物为SiO、AlO、FeO、KO、CaO和MgO，其余为杂质。在间歇系统中对影响CV染料吸附的所有参数进行了优化，优化后的工作条件为平衡时间120分钟、用量30毫克、温度25℃、初始CV浓度400毫克/升。使用非线性等温线和动力学模型对平衡数据进行了测试，结果表明弗伦德利希等温线和准二级动力学与实验数据拟合最佳，表明CV染料与所选微米和纳米粘土表面之间发生了物理化学相互作用。在25℃时，NCQ1和NCQ3吸附剂的最大吸附容量分别为206.73毫克/克和203.66毫克/克。热力学因素表明，微米和纳米粘土对CV染料的吸附是自发的，且为放热过程。因此，所研究的天然微米和纳米粘土吸附剂有望成为从水环境中去除CV染料的有效吸附剂。
