Iqbal Zafar, Tanweer Mohd Saquib, Alam Masood
Environmental Science Research Lab, Department of Applied Sciences & Humanities, Faculty of Engineering & Technology, Jamia Millia Islamia, New Delhi 110025, India.
ACS Omega. 2023 Feb 13;8(7):6376-6390. doi: 10.1021/acsomega.2c06636. eCollection 2023 Feb 21.
This work is dedicated to the synthesis, characterization, and adsorption performance of reduced graphene oxide-modified spinel cobalt ferrite nanoparticles. The as-synthesized reduced graphene oxide cobalt ferrite (RGCF) nanocomposite has been characterized using FTIR spectroscopy, FESEM coupled with EDXS, XRD, HRTEM, zeta potential, and vibrating sample magnetometer (VSM) measurements. FESEM proves the particle size in the range of 10 nm. FESEM, EDX, TEM, FTIR, and XPS analyses provide the proof of successful incorporation of rGO sheets with cobalt ferrite nanoparticles. The crystallinity and spinel phase of cobalt ferrite nanoparticles have been shown by XRD results. The saturation magnetization ( ) was measured as 23.62 emu/g, proving the superparamagnetic behavior of RGCF. The adsorption abilities of the synthesized nanocomposite have been tested using cationic crystal violet (CV) and brilliant green (BG) and anionic methyl orange (MO) and Congo red (CR) dyes. The adsorption trend for MO, CR, BG, and As(V) follows RGCF > rGO > CF at neutral pH. Adsorption studies have been accomplished by optimizing parameters like pH (2-8), adsorbent dose (1-3 mg/25 mL), initial concentration (10-200 mg/L), and contact time at constant room temperature (). To further investigate the sorption behavior, isotherm, kinetics, and thermodynamic studies have been conducted. Langmuir isotherm and pseudo-second-order kinetic models suited better for the adsorption of dyes and heavy metals. The maximum adsorption capacities ( ) obtained have been found as 1666.7, 1000, 416.6, and 222.2 mg/g for MO, CR, BG, and As, respectively, with operational parameters such as = 298.15 K; RGCF dose: 1 mg for MO and 1.5 mg each for CR, BG, and As. Thus, the RGCF nanocomposite was found to be an excellent adsorbent for the removal of dyes and heavy metals.
本工作致力于还原氧化石墨烯修饰的尖晶石型钴铁氧体纳米粒子的合成、表征及吸附性能研究。采用傅里叶变换红外光谱（FTIR）、场发射扫描电子显微镜（FESEM）联用能谱仪（EDXS）、X射线衍射仪（XRD）、高分辨透射电子显微镜（HRTEM）、zeta电位和振动样品磁强计（VSM）对合成的还原氧化石墨烯钴铁氧体（RGCF）纳米复合材料进行了表征。FESEM证实粒径在10 nm范围内。FESEM、EDX、TEM、FTIR和XPS分析证明了rGO片层与钴铁氧体纳米粒子成功复合。XRD结果表明了钴铁氧体纳米粒子的结晶度和尖晶石相。测得饱和磁化强度（ ）为23.62 emu/g，证明了RGCF的超顺磁性行为。使用阳离子结晶紫（CV）和亮绿（BG）以及阴离子甲基橙（MO）和刚果红（CR）染料测试了合成纳米复合材料的吸附能力。在中性pH条件下，MO、CR、BG和As（V）的吸附趋势为RGCF > rGO > CF。通过优化pH（2 - 8）、吸附剂剂量（1 - 3 mg/25 mL）、初始浓度（10 - 200 mg/L）和在恒定室温下的接触时间等参数完成了吸附研究。为进一步研究吸附行为，进行了等温线、动力学和热力学研究。Langmuir等温线和准二级动力学模型更适合染料和重金属的吸附。在 = 298.15 K；RGCF剂量：MO为1 mg，CR、BG和As各为1.5 mg等操作参数下，MO、CR、BG和As的最大吸附容量（ ）分别为1666.7、1000、416.6和222.2 mg/g。因此，发现RGCF纳米复合材料是去除染料和重金属的优良吸附剂。
