Wang Jie, Huang Junhao, Meng Jun, Pan Genxing, Li Yong, Li Zhangtao, Ok Yong Sik
Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China.
Key Laboratory of Recycling and Eco-Treatment of Waste Biomass of Zhejiang Province, School of Environment and Natural Resources, Zhejiang University of Science and Technology, Hangzhou, 310023, China; Institute of Resource, Ecosystem and Environment of Agriculture, and Department of Soil Science, Nanjing Agricultural University, Nanjing, 210095, China.
J Environ Manage. 2025 Jan;373:123585. doi: 10.1016/j.jenvman.2024.123585. Epub 2024 Dec 7.
Pristine or modified nanoscale zero-valent iron (nZVI) synthesized though conventional chemical reduction have been widely recommended for remediating metal(loid)-contaminated water. However, their eco-friendliness is often challenged with the concomitant bio-toxicity and secondary environmental risks. Alternatively, this study utilized waste tea leaves extract and remaining residue as the reducing agent and pyrolytic matrix to innovatively fabricate a green synthesized nZVI impregnated tea residue biochar (G-nZVI/TB). Since the performances, mechanisms, and potential applications of G-nZVI/TB for simultaneous removal of metal cation and metalloid anion remain unclear, typical synthetic aqueous solutions and real wastewaters were systematically tested. The adsorption isotherms showed that the calculated maximum adsorption capacities of G-nZVI/TB for various meta(loid)s were 1.4-10.7 fold higher than those of TB. Although Cd(II) competed with Pb(II) for adsorption on G-nZVI/TB, they synergistically promoted As(III) sequestration. The SEM and FTIR spectra demonstrated that G-nZVI nanoparticles were uniformly dispersed onto TB framework, whereas newly grafted groups like Fe-O, C=O, and C-N accelerated metal(loid)s bonding. The results of batch experiments, XRD, and XPS comprehensively elucidated that metal(loid)s were predominantly separated from polynary systems via electrostatic adsorption, ion exchange, co-precipitation, cation-π interaction, oxidation-complexation, and B-type ternary complexation. In synthetic industrial wastewater and real paddy field drainage with divergent environmental conditions, 0.5 g L optimized G-nZVI/TB efficiently captured over 92.4% metal(loid)s at their concentrations ranging from 0.04 to 3 mg L, indicating its excellent selective adsorption effectiveness and extensive compatibility for practical application in reusing multi-metal(loid)s contaminated wastewater. Overall, these findings provide new insights into developing green nano-functional materials for sustainable water purification.
通过传统化学还原法合成的原始或改性纳米零价铁（nZVI）已被广泛推荐用于修复金属（类金属）污染的水体。然而，它们的生态友好性常常受到伴随而来的生物毒性和二次环境风险的挑战。另外，本研究利用废茶叶提取物和剩余残渣作为还原剂和热解基质，创新性地制备了绿色合成的负载nZVI的茶渣生物炭（G-nZVI/TB）。由于G-nZVI/TB同时去除金属阳离子和类金属阴离子的性能、机制及潜在应用尚不清楚，因此对典型合成水溶液和实际废水进行了系统测试。吸附等温线表明，G-nZVI/TB对各种金属（类金属）的计算最大吸附容量比TB高1.4至10.7倍。虽然Cd(II)与Pb(II)在G-nZVI/TB上竞争吸附，但它们协同促进了As(III)的螯合。扫描电子显微镜（SEM）和傅里叶变换红外光谱（FTIR）表明，G-nZVI纳米颗粒均匀分散在TB骨架上，而新接枝的基团如Fe-O、C=O和C-N促进了金属（类金属）的键合。批量实验、X射线衍射（XRD）和X射线光电子能谱（XPS）的结果综合表明，金属（类金属）主要通过静电吸附、离子交换沉淀、阳离子-π相互作用、氧化络合和B型三元络合从多元体系中分离出来。在环境条件不同的合成工业废水和实际稻田排水中，0.5 g L优化后的G-nZVI/TB在金属（类金属）浓度为0.04至3 mg L时能有效捕获超过92.4%的金属（类金属），表明其具有优异的选择性吸附效果和广泛的兼容性，可实际应用于多金属（类金属）污染废水的回用。总体而言，这些发现为开发用于可持续水净化的绿色纳米功能材料提供了新的见解。
