Environmental Nanoscience Laboratory, Department of Earth Sciences, Indian Institute of Science Education and Research- Kolkata, Mohanpur, West Bengal, 741246, India.
Environmental Nanoscience Laboratory, Department of Earth Sciences, Indian Institute of Science Education and Research- Kolkata, Mohanpur, West Bengal, 741246, India; Centre for Climate and Environmental Studies, Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India.
Environ Res. 2023 Oct 15;235:116605. doi: 10.1016/j.envres.2023.116605. Epub 2023 Jul 10.
The unceasing release of tiny plastics (microplastics and nanoplastics) and their additives, like metal ions, into the aquatic systems from industries and other sources is a globally escalating problem. Their combined toxic effects and human health hazard are already proven; hence, their remediation is requisite. This study utilised the nano-zerovalent iron-loaded sugarcane bagasse-derived biochar (nZVI-SBC) for simultaneous removal of Nanoplastics (NPs) of different functionality and size along with metal ions (Ni, Cd, AsO, and CrO). Batch and column experiments were conducted, and the results showed an efficient removal of contaminants with maximum sorption of carboxylate-modified NPs of size 500 nm (q = 90.3 mg/g) among all three NPs types. Significant removal was observed in Cd in case of cations and CrO in case of anions with q = 44.0 and 87.8 mg/g, respectively. Kinetics and the isotherm modelling better fitted the pseudo-second-order kinetic model and Sips isotherm model, respectively for both NPs and metal ions. The designed material worked well in pH range of 4-8, ionic strength 1-20 mM and in complex aqueous matrices, with >90% removal. FTIR, zeta potential and the imaging analysis of the reaction precipitates confirmed the electrostatic attraction, pore retention and complexation as the potential mechanisms for removing NPs, whereas, XPS studies confirmed the reduction co-precipitation and surface complexation as the possible mechanism for removing metal ions. High values of attachment efficiency factor calculated from colloidal filtration theory (CFT) validated the experimental results and justified the high sorption of carboxylate modified 500 nm NPs particles. The synthesized material successfully removed both NPs of varying size and functionality and metal ions simultaneously with significant efficacy in complex environmental samples proving the broad applicability of material in realistic environmental conditions and different types of water treatment processes.
工业和其他来源不断将微小塑料（微塑料和纳米塑料）及其添加剂（如金属离子）释放到水生系统中，这是一个全球日益严重的问题。它们的联合毒性效应和对人类健康的危害已经得到证实；因此，有必要对其进行修复。本研究利用负载纳米零价铁的甘蔗渣衍生生物炭（nZVI-SBC）同时去除不同功能和尺寸的纳米塑料（NPs）以及金属离子（Ni、Cd、AsO 和 CrO）。进行了批量和柱实验，结果表明，该材料对三种 NPs 类型中尺寸为 500nm 的羧基化修饰 NPs 的污染物去除效率最高（q=90.3mg/g）。在阳离子中，Cd 的去除效果显著，而在阴离子中，CrO 的去除效果显著，分别为 q=44.0 和 87.8mg/g。动力学和等温线模型分别更适合于 NPs 和金属离子的准二级动力学模型和 Sips 等温线模型。该设计材料在 pH 值为 4-8、离子强度为 1-20mM 和复杂水基质中均能良好运行，去除率大于 90%。反应沉淀物的傅里叶变换红外光谱（FTIR）、动电电位和成像分析证实了静电吸引、孔保留和络合是去除 NPs 的潜在机制，而 XPS 研究证实了还原共沉淀和表面络合是去除金属离子的可能机制。胶体过滤理论（CFT）计算的高附着效率因子值验证了实验结果，并证明了对羧基化修饰的 500nm NPs 颗粒的高吸附性。该合成材料成功地同时去除了不同尺寸和功能的 NPs 和金属离子，在复杂的环境样品中具有显著的去除效果，证明了该材料在实际环境条件下和不同类型的水处理过程中的广泛适用性。
