Prakash Vivek, Kumari Kalpana, Ramakrishnan Vibin
Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati781039, Assam, India.
ACS Omega. 2022 Dec 20;8(1):915-924. doi: 10.1021/acsomega.2c06268. eCollection 2023 Jan 10.
The triphenyl group (trityl radical) possessing three-phenyl rings, self-assembled through aromatic π-π stacking interactions, can form interesting crystalline organic nano-flowers. In this work, we have synthesized a hybrid material of 1,2-bis(tritylthio)ethane and magnetite, which reduces toxic Cr(VI) to non-toxic Cr(III). We validated the efficacy of the hybrid in reducing toxic Cr(VI) along with three other adsorbent systems. Among the five adsorbent systems tested, we observed that human hair has higher Cr removal efficiency, which prompted us to explore further using different mechanical forms of human hair. Pulverized hair (PH), hair powder (HP), and raw hair (RH) were evaluated by employing different reaction factors such as the adsorbent dose, pH, initial Cr(VI) concentration, and contact time. The comparative evaluation showed that PH has greater adsorption capacity (15.14 mg/g), followed by RH (13.27 mg/g) and HP (10.5 mg/g). While investigating the adsorption mechanism, we observed that it follows pseudo-second-order kinetics suggesting chemisorption. The Freundlich isotherm model fitted well for Cr(VI) adsorption by human hair, suggesting a multi-layered adsorption process. Overall, this study promises a cost-effective and eco-friendly bio-adsorbent for Cr(VI), which may be scaled up to design automated industrial waste disposal systems.
具有三个苯环的三苯基(三苯甲基自由基)通过芳香π-π堆积相互作用自组装,可形成有趣的结晶有机纳米花。在这项工作中,我们合成了1,2-双(三苯甲基硫基)乙烷与磁铁矿的混合材料,该材料可将有毒的Cr(VI)还原为无毒的Cr(III)。我们验证了该混合材料与其他三种吸附剂体系在还原有毒Cr(VI)方面的功效。在测试的五种吸附剂体系中,我们观察到人类头发具有更高的Cr去除效率,这促使我们进一步探索使用不同机械形式的人类头发。通过采用不同的反应因素,如吸附剂剂量、pH值、初始Cr(VI)浓度和接触时间,对粉碎头发(PH)、头发粉末(HP)和原生头发(RH)进行了评估。比较评估表明,PH具有更大的吸附容量(15.14 mg/g),其次是RH(13.27 mg/g)和HP(10.5 mg/g)。在研究吸附机理时,我们观察到它遵循拟二级动力学,表明是化学吸附。Freundlich等温线模型很好地拟合了人类头发对Cr(VI)的吸附,表明是一个多层吸附过程。总体而言,这项研究有望为Cr(VI)提供一种经济高效且环保的生物吸附剂,这可能会扩大规模以设计自动化工业废物处理系统。