Alagha Omar, Manzar Mohammad Saood, Zubair Mukarram, Anil Ismail, Mu'azu Nuhu Dalhat, Qureshi Aleem
Environmental Engineering Department, College of Engineering A13, Imam Abdulrahman Bin Faisal University, Main Campus, P.O. Box 1982, Dammam 34212, Saudi Arabia.
Nanomaterials (Basel). 2020 Jul 12;10(7):1361. doi: 10.3390/nano10071361.
This experimental work focused on the synthesis, characterization, and testing of a unique, magnetically separable, and eco-friendly adsorbent composite material for the advanced treatment and efficient removal of nitrate and phosphate pollutants from wastewater. The MgAl-augmented double-layered hydroxide (Mg-Fe/LDH) intercalated with sludge-based activated carbon (SBAC-MgFe) composites were characterized by FT-IR, XRD, BET, VSM, SEM, and TEM techniques, revealing homogeneous and efficient dispersion of MgFe/LDH within the activated carbon (AC) matrix, a highly mesoporous structure, and superparamagnetic characteristics. The initial solution pH, adsorbent dose, contact time, and temperature parameters were optimized in order to reach the best removal performance for both pollutants. The maximum adsorption capacities of phosphate and nitrate were found to be 110 and 54.5 mg/g, respectively. The competition between phosphate and coexisting ions (Cl, CO, and SO) was studied and found to be remarkably lower in comparison with the nitrate adsorption. The adsorption mechanisms were elucidated by kinetic, isotherm, thermodynamic modeling, and post-adsorption characterizations of the composite. Modeling and mechanistic studies demonstrated that physisorption processes such as electrostatic attraction and ion exchange mainly governed the nitrate and phosphate adsorption. The composite indicated an outstanding regeneration performance even after five sequences of adsorption/desorption cycles. The fabricated composite with magnetically separable characteristics can be used as a promising adsorbent for the removal of phosphate and nitrate pollutants from wastewater.
这项实验工作聚焦于一种独特的、可磁分离且环保的吸附剂复合材料的合成、表征及测试，用于深度处理和高效去除废水中的硝酸盐和磷酸盐污染物。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、比表面积分析（BET）、振动样品磁强计（VSM）、扫描电子显微镜（SEM）和透射电子显微镜（TEM）技术对插层有污泥基活性炭（SBAC-MgFe）的镁铝增强双层氢氧化物（Mg-Fe/LDH）复合材料进行了表征，结果表明MgFe/LDH在活性炭（AC）基质中均匀且高效分散，具有高度介孔结构和超顺磁性特征。对初始溶液pH值、吸附剂剂量、接触时间和温度参数进行了优化，以实现对两种污染物的最佳去除性能。发现磷酸盐和硝酸盐的最大吸附容量分别为110和54.5 mg/g。研究了磷酸盐与共存离子（Cl、CO和SO）之间的竞争，发现与硝酸盐吸附相比，其竞争明显较低。通过动力学、等温线、热力学建模以及复合材料的吸附后表征对吸附机制进行了阐释。建模和机理研究表明，静电吸引和离子交换等物理吸附过程主要控制着硝酸盐和磷酸盐的吸附。即使经过五个吸附/解吸循环序列，该复合材料仍表现出出色的再生性能。所制备的具有磁分离特性的复合材料可作为一种有前景的吸附剂，用于去除废水中的磷酸盐和硝酸盐污染物。
