Removal of Nickel-Citrate by KOH-Modified Arundo donax L. Biochar: Critical Role of Persistent Free Radicals

IF 11.4 1区环境科学与生态学 Q1 ENGINEERING, ENVIRONMENTAL

Water Research Pub Date : 2025-04-22 DOI:10.1016/j.watres.2025.123652

Wei Liu , Xiaomin Li , Xiaolong Yang , Zhenglin Chen , Shu Liu , Wenhong Fan

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Abstract

Removal of heavy metal complexes (HMCs) from wastewater poses significant challenges to waste water treatment due to the inherent stability of these compounds. In this study, KOH modified Arundo donax L. leaves biochar was developed, which demonstrated a remarkable capacity for nickel-citrate (Ni-Cit) removal. The results found that the modified biochar with a KOH-to-biomass ratio of 1:1 (1KBC) showed over 500-fold increase in specific surface area compared to the original biochar, along with enhanced surface functional groups and persistent free radicals (PFRs). 99.2 % of nickel was removed from 50 mg/L Ni-Cit with 1 g/L of 1KBC in 4 h. It also demonstrated exceptional potential in continuous treatment. LC-MS, EPR analysis, and DFT calculations revealed that the PFRs on the biochar surface played critical role for the Ni-Cit removal. Reactive oxygen species (ROS) initiated by PFRs, especially O₂^•⁻, targeted the Ni-O coordination bonds, resulting in the decomplexation of Ni-Cit, while •OH and ¹O₂ facilitate the decarboxylation of the citrate ligand. The released Ni was then adsorbed onto the biochar. It indicated that the 1KBC removed Ni-Cit in one-step process with combined oxidation and adsorption. This research offers a promising technique for the efficient decomplexation and recovery of HMCs.

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koh修饰的Arundo donax L.生物炭对柠檬酸镍的去除：持久性自由基的关键作用

由于重金属配合物固有的稳定性，从废水中去除重金属配合物（hmc）对废水处理提出了重大挑战。本研究利用KOH改性的竹叶生物炭对镍柠檬酸盐（Ni-Cit）进行了脱除。结果发现，koh与生物质比为1:1 （1KBC）的改性生物炭比原始生物炭的比表面积增加了500倍以上，表面官能团和持久性自由基（PFRs）也有所增强。用1 g/L的1KBC在4 h内对50 mg/L Ni-Cit的镍去除率达到99.2%，在连续处理中表现出优异的潜力。LC-MS、EPR分析和DFT计算表明，生物炭表面的PFRs对Ni-Cit的去除起关键作用。由PFRs引发的活性氧（ROS），特别是O₂•毒血症，针对Ni-O配位键，导致Ni-Cit的反复，而•OH和¹O₂促进柠檬酸配体的脱羧。释放出来的镍随后被吸附在生物炭上。结果表明，1KBC采用氧化和吸附相结合的一步法去除Ni-Cit。本研究为hmc的高效分解和恢复提供了一种有前景的技术。

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来源期刊

Water Research 环境科学-工程：环境

CiteScore

20.80

自引率

9.40%

发文量

1307

审稿时长

38 days

期刊介绍： Water Research, along with its open access companion journal Water Research X, serves as a platform for publishing original research papers covering various aspects of the science and technology related to the anthropogenic water cycle, water quality, and its management worldwide. The audience targeted by the journal comprises biologists, chemical engineers, chemists, civil engineers, environmental engineers, limnologists, and microbiologists. The scope of the journal include: •Treatment processes for water and wastewaters (municipal, agricultural, industrial, and on-site treatment), including resource recovery and residuals management; •Urban hydrology including sewer systems, stormwater management, and green infrastructure; •Drinking water treatment and distribution; •Potable and non-potable water reuse; •Sanitation, public health, and risk assessment; •Anaerobic digestion, solid and hazardous waste management, including source characterization and the effects and control of leachates and gaseous emissions; •Contaminants (chemical, microbial, anthropogenic particles such as nanoparticles or microplastics) and related water quality sensing, monitoring, fate, and assessment; •Anthropogenic impacts on inland, tidal, coastal and urban waters, focusing on surface and ground waters, and point and non-point sources of pollution; •Environmental restoration, linked to surface water, groundwater and groundwater remediation; •Analysis of the interfaces between sediments and water, and between water and atmosphere, focusing specifically on anthropogenic impacts; •Mathematical modelling, systems analysis, machine learning, and beneficial use of big data related to the anthropogenic water cycle; •Socio-economic, policy, and regulations studies.