Rehman Ali, Naeem Abdul, Ahmad Ijaz, Fozia Fozia, Almutairi Mikhlid H, Aslam Madeeha, Israr Muhammad, Almutairi Bader O, Ullah Zia
Department of Chemistry, Kohat University of Science & Technology, Kohat 26000, Pakistan.
National Center of Excellence in Physical Chemistry, University of Peshawar, Peshawar 25120, Pakistan.
ACS Omega. 2023 Dec 26;9(1):317-329. doi: 10.1021/acsomega.3c05299. eCollection 2024 Jan 9.
This research study was designed with the aim to prepare plant extract-mediated iron oxide nanoparticles (IONPs) and different chemically modified carbon adsorbents from the plant and then optimize the carbon adsorbents by evaluating their adsorption applications in wastewater for the selected metal ions like arsenic (As), lead (Pb), and cadmium (Cd). The Fourier transform infrared spectroscopy (FTIR) technique was used to highlight functional groups in plant-mediated IONPs and chemically modified carbon adsorbents. A scanning electron microscopy study was conducted to explain the surface morphology of the adsorbents. Energy-dispersive X-rays was used for elemental analysis and X-ray diffraction for particle size and crystallinity of the adsorbents. From the study, it was found that the best optimum conditions were pH = 5-6, initial concentration of adsorbate of 10 mg/L, dose of adsorbent of 0.01 g, contact time of 90-120 min of adsorbent and adsorbate, and temperature of 25 °C. At optimum conditions, the adsorption capacities of IONPs for arsenic (As) 144.7 mg/g, lead (Pb) 128.01 mg/g, and cadmium (Cd) ions 122.1 mg/g were recorded. The activated carbon at optimum conditions showed adsorption capacities of 46.35 mg/g for As, 121.95 mg/g for Pb, and 113.25 mg/g for Cd ion. At equilibrium, Langmuir, Freundlich Temkin, and Dubinin-Radushkevich isotherms were applied on the experimental adsorption data having the best values (0.973-0.999) by the Langmuir isotherm. High-correlation coefficient values (0.996-0.999) were obtained from the pseudo-second-order for all cases, showing that the adsorption process proceeds through pseudo second-order kinetics. The apparent adsorption energy E value was in the range of 0.24-2.36 kJ/mol. The adsorption capacity of regenerated IONPs for As gradually decreased from 144.8 to 45.67 mg/g, for lead 128.15 to 41.65 mg/g, and cadmium from 122.10 to 31.20 mg/g in 5 consecutive cycles. The study showed that the synthesized IONPs and acid-activated carbon adsorbent were successfully used to remove selected metal ions from wastewater.
本研究旨在制备植物提取物介导的氧化铁纳米颗粒（IONPs）以及从该植物中制备不同的化学改性碳吸附剂，然后通过评估它们在废水中对选定金属离子如砷（As）、铅（Pb）和镉（Cd）的吸附应用来优化碳吸附剂。采用傅里叶变换红外光谱（FTIR）技术突出植物介导的IONPs和化学改性碳吸附剂中的官能团。进行扫描电子显微镜研究以解释吸附剂的表面形态。能量色散X射线用于元素分析，X射线衍射用于分析吸附剂的粒径和结晶度。研究发现，最佳条件为pH = 5 - 6、吸附质初始浓度为10 mg/L、吸附剂剂量为0.01 g、吸附剂与吸附质的接触时间为90 - 120分钟以及温度为25℃。在最佳条件下，记录到IONPs对砷（As）的吸附容量为144.7 mg/g、对铅（Pb）为128.01 mg/g、对镉（Cd）离子为122.1 mg/g。最佳条件下的活性炭对As的吸附容量为46.35 mg/g、对Pb为121.95 mg/g、对Cd离子为113.25 mg/g。在平衡时，将朗缪尔、弗伦德里希、坦金和杜比宁 - 拉杜舍维奇等温线应用于实验吸附数据，其中朗缪尔等温线的拟合效果最佳（0.973 - 0.999）。所有情况下，拟二级动力学的相关系数值都很高（0.996 - 0.999），表明吸附过程遵循拟二级动力学。表观吸附能E值在0.24 - 2.36 kJ/mol范围内。再生IONPs对As的吸附容量在连续5个循环中从144.8逐渐降至45.67 mg/g，对铅从128.15降至41.65 mg/g，对镉从122.10降至31.20 mg/g。研究表明，合成的IONPs和酸活化碳吸附剂成功用于从废水中去除选定的金属离子。
