Ruvubu Sylvanus Bisaba, Roy Indrajit
Department of Chemistry, University of Delhi-110007, New Delhi, India; Department of Chemistry and Physics, College of Natural and Applied Sciences, Sokoine University of Agriculture, P. O. Box 3038, Morogoro, Tanzania.
Department of Chemistry, University of Delhi-110007, New Delhi, India.
Int J Biol Macromol. 2025 Mar;292:139293. doi: 10.1016/j.ijbiomac.2024.139293. Epub 2024 Dec 30.
Wastewater contamination by organic dyes, especially Rhodamine B (RhB), possess a significant environmental challenge. This study explores a novel bio sorbent for the removal of RhB dye from contaminated water, using chitosan trisodium citrate-modified magnetic nanoparticles (Fe₃O₄@CSTSC@PANI) coated with polyaniline. The nanocomposite was characterized by FT-IR, XRD, HRTEM, SEM, BET surface analysis. The UV-visible spectroscopy was used to monitor the adsorption of dye on the nanocomposite. The Fe₃O₄@CSTSC@PANI nanocomposite exhibits a spherical core-shell morphology with a size range of 29-53 nm, a BET surface area of 13.099 m/g, and high reusability. The pore area of the material increased from 0.8058 m/g at 15.29 Å radius to 10.65 m/g at 1310.89 Å, with a corresponding change in pore volume from 0.0006.16 cc/g to 0.0227 cc/g. This shows the significant contribution of the porous and mesoporous structures of polyaniline-coated chitosan trisodium citrate (nanocomposites) to the adsorption performance for pollutant capture such as Rhodamine B dye. Adsorption studies showed optimal RhB removal of 97.2 % at near neutral pH. Adsorption was most optimal at pH 6-9, with the highest efficiency near neutral pH, which facilitates electrostatic interactions. High temperature (10-70 °C) promoted the endothermic adsorption process, improving the dye uptake. The optimal adsorbent dosage (0.21-1.6 g/L) and equilibrium contact time (30-840 min) were determined. The nanocomposite material showed good recovery, maintaining high efficiency after 4 reuse cycles, demonstrating its practicality in sustainable environmental remediation. The adsorption mechanism was elucidated by isotherm and kinetic studies, which revealed that the process followed a pathway dominated by chemisorption facilitated by the interaction between polyaniline-coated chitosan nanocomposites and Rhodamine B dye molecules. This is the synergistic effect of electrostatic attraction, hydrogen bonding and π-π interactions, confirming the strong affinity of the mixture for the dye.
有机染料对废水的污染，尤其是罗丹明B（RhB），构成了重大的环境挑战。本研究探索了一种新型生物吸附剂，用于从受污染水中去除RhB染料，该吸附剂使用包覆有聚苯胺的壳聚糖柠檬酸三钠改性磁性纳米颗粒（Fe₃O₄@CSTSC@PANI）。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）、高分辨率透射电子显微镜（HRTEM）、扫描电子显微镜（SEM）、比表面积（BET）分析对该纳米复合材料进行了表征。采用紫外可见光谱法监测染料在纳米复合材料上的吸附情况。Fe₃O₄@CSTSC@PANI纳米复合材料呈现出球形核壳形态，尺寸范围为29 - 53纳米，比表面积为13.099平方米/克，且具有高可重复使用性。材料的孔面积从半径为15.29埃时的0.8058平方米/克增加到半径为1310.89埃时的10.65平方米/克，相应的孔体积从0.0006.16立方厘米/克变化到0.0227立方厘米/克。这表明聚苯胺包覆的壳聚糖柠檬酸三钠（纳米复合材料）的多孔和介孔结构对诸如罗丹明B染料等污染物捕获的吸附性能有显著贡献。吸附研究表明，在接近中性pH值时，对RhB的去除率最佳，可达97.2%。在pH值为6 - 9时吸附最为理想，在接近中性pH值时效率最高，这有利于静电相互作用。高温（10 - 70℃）促进了吸热吸附过程，提高了染料的摄取量。确定了最佳吸附剂用量（0.21 - 1.6克/升）和平衡接触时间（30 - 840分钟）。该纳米复合材料表现出良好的回收率，在4次重复使用循环后仍保持高效，证明了其在可持续环境修复中的实用性。通过等温线和动力学研究阐明了吸附机理，结果表明该过程遵循一条由聚苯胺包覆的壳聚糖纳米复合材料与罗丹明B染料分子之间的相互作用促进的化学吸附主导的途径。这是静电吸引、氢键和π - π相互作用的协同效应，证实了该混合物对染料具有很强的亲和力。
