Abstract:
To address the issue of surface passivation layers on micron-sized zero-valent iron（mZVI） inhibiting electron transfer，a synergistic reduction system combining silico-tungstic acid（STA） and mZVI was established. STA serves as an electron mediator to enhance the rate at which mZVI transfers electrons to reduce hexavalent chromium in groundwater. Through batch experiments，the effects of STA dosage，mZVI dosage，initial pH，Cr（Ⅵ） concentration，and coexisting anions on reaction efficiency were systematically investigated. Through batch experiments，the effects of STA dosage，mZVI dosage，initial pH，Cr（Ⅵ） concentration，and coexisting anions on reaction efficiency were systematically investigated. The study revealed that under optimized conditions（Cr（Ⅵ）=7 mg/L，STA=0.077 g/L，mZVI = 1.5 g/L），the STA/mZVI system achieved a Cr（Ⅵ） removal rate of 96.8% within 60 minutes. The pseudo-first-order kinetic constant k₁ was 0.054 min⁻¹，representing an approximately 52.5-fold improvement over the single mZVI system. Multiscale characterization（XRD，SEM，XPS） confirms that STA significantly enhances the system's electron transfer efficiency through the oxidation state transition of W，overcoming passivation layer resistance. Mechanistic studies reveal that STA markedly strengthens the electron transfer capacity of mZVI，synergistically improving its Cr（Ⅵ） reduction performance，thereby providing technical support for micron-scale zero-valent iron remediation of hexavalent chromium in groundwater.
Key words:
hexavalent chromium,
silicon tungstic acid,
zero-valent iron,
electron shuttle,
synergistic enhancement
摘要：
针对微米级零价铁（mZVI）表面钝化层抑制电子传递的问题，采用硅钨酸（STA）作为电子介体，构建了STA/mZVI协同还原体系，以提高mZVI传递还原地下水中六价铬的速率。通过批量实验，系统考察了STA投加量、mZVI用量、初始pH、Cr（Ⅵ）浓度及共存阴离子对反应效能的影响。研究表明：在优化条件〔Cr（Ⅵ）=7 mg/L，STA=0.077 g/L，mZVI=1.5 g/L〕下，STA/mZVI体系在60 min内对Cr（Ⅵ）的去除率达96.8%，准一级动力学常数k₁为0.054 min-1，较单一mZVI体系提升约52.5倍。多尺度表征（XRD、SEM、XPS）证实，STA 通过 W 元素的价态转显著强化了体系的电子转移效率，克服了钝化层阻力。机理研究表明，STA可显著强化mZVI的电子传递能力，协同提升其对Cr（Ⅵ）的还原性能，为微米级零价铁修复地下水六价铬提供技术支撑。
关键词:
六价铬,
硅钨酸,
微米级零价铁,
电子穿梭,
协同强化
CLC Number:
LI Jiaxin, HU Benyuan, LU Yanshu, LEI Ming, ZHOU Ting, YANG Yu, CHU Xiaodong, MA Zhifei. Synergistic enhancement by silica-tungstic acid on micron-sized zero-valent iron for removing Cr（Ⅵ） from aqueous solution[J]. Industrial Water Treatment, doi: 10.19965/j.cnki.iwt.2025-0960.
李佳欣, 胡本源, 卢彦澍, 雷 明, 周 廷, 杨 昱, 储小东, 马志飞. 硅钨酸协同强化微米级零价铁去除水中六价铬研究[J]. 工业水处理, doi: 10.19965/j.cnki.iwt.2025-0960.