Wedajo Temesgen, Mekonnen Andualem, Alemu Tadesse
National Soil Testing Center, Addis Ababa, Ethiopia.
Center for Environmental Science, Addis Ababa University, Addis Ababa, Ethiopia.
J Environ Health Sci Eng. 2023 Apr 25;21(1):277-291. doi: 10.1007/s40201-023-00860-3. eCollection 2023 Jun.
Nanomaterial assisted removal of pollutants from water has got great attention. This study aimed to remove nitrate from groundwater using zeolite and zeolite-ZnO nanocomposite as synergetic effect. Zeolite-ZnO nanocomposite was prepared using the co-precipitation method. The Physico-chemical characteristics of the nanomaterials were determined using XRD, SEM, and FTIR. The results revealed that; Zeolite-ZnO nanocomposites with 13.12 nm particle size have successfully been loaded into the zeolite. In addition, its chemical composition was determined using AAS. The removal efficiency of nitrate from groundwater was studied using a batch experiment. The removal of nitrate was investigated as a function of adsorbent dose, pH, initial concentration of nitrate, contact time, and agitation speed. Moreover, the adsorption isotherm and kinetics were also determined. The results showed that the removal of nitrate was 92% at an optimum dose of 0.5 g, pH 5, initial nitrate concentration of 50 mg/L, the contact time of 1 h, and agitation speed of 160 rpm. The removal nitrate has been fitted well by the Langmuir isotherm model with correlation coefficients of R = 0.988. Thus, indicating the applicability of monolayer coverage of the nitrate ion on the surface of the nanocomposite. The adsorption process follows the pseudo-second-order model with a correlation coefficient of R = 0.997. The results of this work might find application in remediation of water by removing nitrate to meet the standards of water quality.
纳米材料辅助去除水中污染物已备受关注。本研究旨在利用沸石和沸石 - 氧化锌纳米复合材料的协同效应去除地下水中的硝酸盐。采用共沉淀法制备了沸石 - 氧化锌纳米复合材料。使用X射线衍射仪（XRD）、扫描电子显微镜（SEM）和傅里叶变换红外光谱仪（FTIR）测定了纳米材料的物理化学特性。结果表明，粒径为13.12纳米的沸石 - 氧化锌纳米复合材料已成功负载到沸石中。此外，还使用原子吸收光谱法（AAS）测定了其化学成分。通过批次实验研究了地下水中硝酸盐的去除效率。研究了硝酸盐的去除与吸附剂剂量、pH值、硝酸盐初始浓度、接触时间和搅拌速度的关系。此外，还确定了吸附等温线和动力学。结果表明，在最佳剂量0.5克、pH值为5、初始硝酸盐浓度为50毫克/升、接触时间为1小时和搅拌速度为160转/分钟的条件下，硝酸盐的去除率为92%。硝酸盐的去除很好地符合朗缪尔等温线模型，相关系数R = 0.988。因此，表明硝酸盐离子在纳米复合材料表面的单层覆盖具有适用性。吸附过程遵循伪二级模型，相关系数R = 0.997。这项工作的结果可能在通过去除硝酸盐来满足水质标准的水修复中得到应用。
