{"title":"Enhanced mechanical properties and chromium (VI) immobilization via defect-tailored UiO-66-(OH)2 in cement-stabilized iron tailings","authors":"Jian Jia , Mei-Ling Xu , Xiao-Jie Jiang , Li-Na Zhang , Xiao-Lei Lu , Jiang Zhu , Xin Cheng","doi":"10.1016/j.conbuildmat.2024.139324","DOIUrl":null,"url":null,"abstract":"<div><div>The utilization of cement-stabilized iron tailings as pavement base necessitates rigorous scrutiny of heavy metal ion leaching, particularly under fluctuating environmental pH conditions. Given the insufficient capacity of cement to stabilize Cr(Ⅵ), this paper explores the integration of defect-engineered metal-organic frameworks (MOFs) as additives in cement-stabilized iron tailings to reduce Cr(Ⅵ) leaching. Results shows that the utilization of MOFs material mitigates Cr(VI) leaching in cement-stabilized iron tailings while enhancing their mechanical properties. The Cr(Ⅵ) leaching from samples with the addition of UiO-66-(OH)₂ and UiO-66-(OH)₂-D exhibited a substantial reduction of 60.2 % and 88.6 %, respectively. The stabilized mechanism is attributed to the strong affinity between Cr(Ⅵ) and hydroxyl groups in MOFs. Furthermore, UiO-66-(OH)<sub>2</sub>-D has a larger pore diameter to expose more hydroxyl groups, which greatly improves its adsorption performance for Cr(Ⅵ). Meanwhile, the unconfined compressive strength (UCS), splitting strength and compressive resilience modulus increased by 13.4 %, 35.1 % and 45.7 %, respectively. The mechanisms underlie that the MOFs enhanced the early hydration process and optimized of the pore size distribution within the solidified body. This study presents a viable and efficient approach for the sustained mitigation of Cr(Ⅵ) leaching within cement-stabilized iron tailings.</div></div>","PeriodicalId":288,"journal":{"name":"Construction and Building Materials","volume":"457 ","pages":"Article 139324"},"PeriodicalIF":7.4000,"publicationDate":"2024-11-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Construction and Building Materials","FirstCategoryId":"5","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0950061824044660","RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CONSTRUCTION & BUILDING TECHNOLOGY","Score":null,"Total":0}
引用次数: 0
Abstract
The utilization of cement-stabilized iron tailings as pavement base necessitates rigorous scrutiny of heavy metal ion leaching, particularly under fluctuating environmental pH conditions. Given the insufficient capacity of cement to stabilize Cr(Ⅵ), this paper explores the integration of defect-engineered metal-organic frameworks (MOFs) as additives in cement-stabilized iron tailings to reduce Cr(Ⅵ) leaching. Results shows that the utilization of MOFs material mitigates Cr(VI) leaching in cement-stabilized iron tailings while enhancing their mechanical properties. The Cr(Ⅵ) leaching from samples with the addition of UiO-66-(OH)₂ and UiO-66-(OH)₂-D exhibited a substantial reduction of 60.2 % and 88.6 %, respectively. The stabilized mechanism is attributed to the strong affinity between Cr(Ⅵ) and hydroxyl groups in MOFs. Furthermore, UiO-66-(OH)2-D has a larger pore diameter to expose more hydroxyl groups, which greatly improves its adsorption performance for Cr(Ⅵ). Meanwhile, the unconfined compressive strength (UCS), splitting strength and compressive resilience modulus increased by 13.4 %, 35.1 % and 45.7 %, respectively. The mechanisms underlie that the MOFs enhanced the early hydration process and optimized of the pore size distribution within the solidified body. This study presents a viable and efficient approach for the sustained mitigation of Cr(Ⅵ) leaching within cement-stabilized iron tailings.
期刊介绍:
Construction and Building Materials offers an international platform for sharing innovative and original research and development in the realm of construction and building materials, along with their practical applications in new projects and repair practices. The journal publishes a diverse array of pioneering research and application papers, detailing laboratory investigations and, to a limited extent, numerical analyses or reports on full-scale projects. Multi-part papers are discouraged.
Additionally, Construction and Building Materials features comprehensive case studies and insightful review articles that contribute to new insights in the field. Our focus is on papers related to construction materials, excluding those on structural engineering, geotechnics, and unbound highway layers. Covered materials and technologies encompass cement, concrete reinforcement, bricks and mortars, additives, corrosion technology, ceramics, timber, steel, polymers, glass fibers, recycled materials, bamboo, rammed earth, non-conventional building materials, bituminous materials, and applications in railway materials.