Mudzielwana Rabelani, Gitari Mugera Wilson, Ndungu Patrick
Environmental Remediation and Nano Science, Department of Ecology and Resource Management, University of Venda, Thohoyandou, South Africa.
Department of Applied Chemistry, University of Johannesburg, Johannesburg, South Africa.
Front Chem. 2020 Jan 15;7:913. doi: 10.3389/fchem.2019.00913. eCollection 2019.
In this study, a hybrid arsenic adsorbent was synthesized through intercalation inorganic and organic surfactant cations onto kaolin clay interlayers. The synthesized adsorbent was characterized X-ray fluorescence (XRF), Fourier Transform Infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET). Batch studies were conducted to determine As(III) and As(V) removal capacity of hybrid sorbent synthesized. It is found that As(III) removal is optimum at pH range of 4-6 while As(V) removal is optimum at pH range 4-8. The data for adsorption kinetics fitted to pseudo second order model implying that adsorption of As(III) and As(V) is chemisorption. The isotherm studies showed a better fit to Langmuir isotherm model indicating that adsorption of both As(III) and As(V) occurred on a mono-layered surface. The maximum adsorption As(III) and As(V) capacity at room temperature as determined by Langmuir model were found to be 7.99 and 7.32 mg/g, respectively. Thermodynamic parameters, ΔG° and ΔH° were found to be negative indicating that adsorption process occurred spontaneously and exothermic. Inorgano-organo modified kaolin clay was successfully regenerated for up 7 adsorption-regeneration cycles using 0.01 M HCl as regenerant. This study concluded that hybrid sorbent synthesized in this study is suitable for arsenic removal from groundwater.
在本研究中,通过将无机和有机表面活性剂阳离子插层到高岭土粘土层间合成了一种混合砷吸附剂。采用X射线荧光光谱(XRF)、傅里叶变换红外光谱(FTIR)、扫描电子显微镜(SEM)和布鲁诺尔-埃米特-泰勒(BET)法对合成的吸附剂进行了表征。进行了批量研究以确定合成的混合吸附剂对As(III)和As(V)的去除能力。结果发现,As(III)在pH值为4 - 6的范围内去除效果最佳,而As(V)在pH值为4 - 8的范围内去除效果最佳。吸附动力学数据符合伪二级模型,这意味着As(III)和As(V)的吸附是化学吸附。等温线研究表明,其更符合朗缪尔等温线模型,表明As(III)和As(V)的吸附均发生在单层表面。通过朗缪尔模型测定,室温下As(III)和As(V)的最大吸附容量分别为7.99和7.32 mg/g。发现热力学参数ΔG°和ΔH°为负值,表明吸附过程是自发且放热的。使用0.01 M HCl作为再生剂,无机-有机改性高岭土粘土成功再生了多达7个吸附-再生循环。本研究得出结论,本研究中合成的混合吸附剂适用于从地下水中去除砷。