Department of Chemical Engineering, National Institute of Technology Agartala, Agartala, Tripura, 799046, India.
Department of Chemical & Polymer Engineering, Tripura University, Agartala, 799022, India.
Environ Sci Pollut Res Int. 2022 Dec;29(57):86528-86549. doi: 10.1007/s11356-022-21702-z. Epub 2022 Jun 30.
Heavy metal-contaminated water can be effectively treated using adsorbents made from abundantly available biomass. The present investigation was carried out to adsorb Cd(II) from synthetic solution by banana pseudo-stem (BP) and Moringa oleifera stem bark (MB). Adsorption efficiencies of both adsorbents were studied in the batch reactor by conducting experiments to determine the consequences of changes of pH, adsorbent dosages, initial Cd(II) concentrations, incubation time, and temperature. The process parameters were tuned to attain the highest possible removal percentage. The characterization of the adsorbents was performed by utilizing Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FESEM), and energy-dispersive X-ray (EDX) for the fresh and metal-loaded adsorbents. Atomic absorption spectroscopy (AAS) was employed to calculate the amount of Cd(II) in an aqueous solution. The experimental data were entirely consistent with the pseudo-second-order model for BP and MB. The findings of the study illustrated the better adsorption efficiency of BP-derived adsorbent (≈ 99%) at optimum conditions over the MB (≈ 97%), and the corresponding adsorption capacities were 11.98 and 7.04 mg/g, respectively. The 4 (four) well-known isotherm models were attempted both in linear and non-linear forms. BP (R =0.995) and MB (R =0.994) were found to be best described by the Freundlich isotherm, which was selected based on the highest R value. In thermodynamic studies, ΔH and ΔS were calculated for both the adsorbents. Cd(II) adsorption on BP and MB was endothermic, as evidenced by the positive ΔH. Finally, the prediction of the removal percentage was made by the artificial neural network (ANN) modelling. The present work developed regionally derived waste materials which are helpful for small-scale industrial units for their waste management in an economical and sustainable way.
受重金属污染的水可以通过使用丰富的生物质制成的吸附剂来有效处理。本研究采用香蕉假茎（BP）和辣木树皮（MB）从合成溶液中吸附 Cd(II)，在间歇反应器中进行实验，研究了两种吸附剂的吸附效率，以确定 pH 值、吸附剂用量、初始 Cd(II)浓度、孵育时间和温度变化的影响。调整工艺参数以达到最高可能的去除率。利用傅里叶变换红外光谱（FTIR）、场发射扫描电子显微镜（FESEM）和能量色散 X 射线（EDX）对新鲜和负载金属的吸附剂进行了表征。原子吸收光谱（AAS）用于计算水溶液中 Cd(II)的含量。实验数据完全符合 BP 和 MB 的拟二级模型。研究结果表明，在最佳条件下，BP 衍生的吸附剂（≈99%）对 Cd(II)的吸附效率优于 MB（≈97%），相应的吸附容量分别为 11.98 和 7.04mg/g。尝试了 4 种（四种）著名的等温线模型，包括线性和非线性形式。BP（R=0.995）和 MB（R=0.994）均被发现最符合 Freundlich 等温线模型，该模型是基于最高 R 值选择的。在热力学研究中，计算了两种吸附剂的ΔH 和ΔS。BP 和 MB 上的 Cd(II)吸附是吸热的，这是由正ΔH 证明的。最后，通过人工神经网络（ANN）建模对去除率进行了预测。本工作开发了具有区域特色的废料，有助于小型工业单位以经济和可持续的方式进行废物管理。
