Effects and mechanisms of zero-valent iron-loaded corn straw biochars on Cd(II) adsorption onto loessial soil

IF 5.4 2区化学 Q2 CHEMISTRY, PHYSICAL

Colloids and Surfaces A: Physicochemical and Engineering Aspects Pub Date : 2026-05-20 Epub Date: 2026-01-30 DOI:10.1016/j.colsurfa.2026.139729

Xujun Nan , Baowei Zhao , Fengfeng Ma , Yuling Chen , Hai Wang , Dengdi Xu

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引用次数: 0

Abstract

Cadmium (Cd) contamination in loess is a growing environmental concern due to its toxicity and mobility. Stabilization-based remediation technology is a promising approach, and Fe⁰-modified biochar exhibits strong immobilization performance. In this study, nano zero-valent iron (nZVI) was synthesized via the liquid-phase reduction method and loaded onto corn straw biochar prepared at 300°C and 600°C (MSB300 and MSB600) to form composite adsorbents (nZVI@MSB300 and nZVI@MSB600). The adsorption behavior of Cd(II) on loess soil (Ls) and 1:9 (w/w) biochar–soil mixtures (nZVI@MSB300-Ls and nZVI@MSB600-Ls) was investigated by batch experiments. The effects of contact time, initial Cd(II) concentration, and solution pH on the adsorption behavior were tested. Kinetics, isotherms, and material characterization were investigated to elucidate the sorption performance and mechanisms. The maximum adsorption capacities of Ls, nZVI@MSB300-Ls, and nZVI@MSB600-Ls for Cd(Ⅱ) were 6.3, 9.8, and 13.0 mg/g, respectively, with nZVI@MSB600-Ls exhibiting the highest performance. The adsorption kinetics conformed to the pseudo-second-order model (R²≥0.91), and the adsorption isotherms fitted the Langmuir model (R²≥0.95), indicating a chemisorption-dominated mechanism. Post-adsorption characterization using Scanning electron microscope-Energy dispersive spectrometer (SEM–EDS), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), and X-ray photoelectron spectroscopy (XPS) revealed that nZVI@MSB300 and nZVI@MSB600 mainly immobilized Cd(II) through complexation, cation exchange, cation–π interactions, and precipitation, whereas loess primarily relied on complexation and precipitation. These results demonstrate that nZVI@MSB amendment effectively enhances Cd(II) adsorption onto loess, offering a promising immobilization strategy for mitigating cadmium contamination in soils.

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零价载铁玉米秸秆生物炭对黄土吸附Cd（II）的影响及机理

黄土中的镉污染因其毒性和流动性而日益受到环境问题的关注。基于稳定的修复技术是一种很有前途的方法，fe0修饰的生物炭具有很强的固定化性能。本研究采用液相还原法合成纳米零价铁（nZVI），并将其负载于300℃和600℃制备的玉米秸秆生物炭（MSB300和MSB600）上，形成复合吸附剂（nZVI@MSB300和nZVI@MSB600）。通过批量试验研究了Cd（II）在黄土（Ls）和1:9 （w/w）生物炭-土壤混合物（nZVI@MSB300-Ls和nZVI@MSB600-Ls）上的吸附行为。考察了接触时间、初始Cd（II）浓度和溶液pH对吸附行为的影响。研究了吸附动力学、等温线和材料表征，以阐明吸附性能和机理。Ls、nZVI@MSB300-Ls和nZVI@MSB600-Ls对Cd（Ⅱ）的最大吸附量分别为6.3、9.8和13.0 mg/g，其中nZVI@MSB600-Ls的吸附性能最好。吸附动力学符合拟二阶模型（R²≥0.91），吸附等温线符合Langmuir模型（R²≥0.95），表明吸附机理以化学吸附为主。利用扫描电镜-能谱仪（SEM-EDS）、傅里叶变换红外光谱（FTIR）、x射线衍射光谱（XRD）和x射线光电子能谱（XPS）对吸附后物质进行表征，发现nZVI@MSB300和nZVI@MSB600主要通过络合、阳离子交换、阳离子-π相互作用和沉淀来固定Cd(II)，而黄土主要通过络合和沉淀来固定Cd（II）。结果表明，nZVI@MSB改性剂能有效增强黄土对Cd（II）的吸附，为缓解土壤镉污染提供了一种有前景的固定化策略。

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来源期刊

Colloids and Surfaces A: Physicochemical and Engineering Aspects 化学-物理化学

CiteScore

8.70

自引率

9.60%

发文量

2421

审稿时长

56 days

期刊介绍： Colloids and Surfaces A: Physicochemical and Engineering Aspects is an international journal devoted to the science underlying applications of colloids and interfacial phenomena. The journal aims at publishing high quality research papers featuring new materials or new insights into the role of colloid and interface science in (for example) food, energy, minerals processing, pharmaceuticals or the environment.