Environmental Earth Sciences
·
2021
·Vol. 81
·期 1
·1-11
·
IF 2.784
Suo Chongxian,Yao Xin,Song Zhiwei,Dong Xiaoqiang
There is an urgency to develop a more economical and environmentally friendly solidifier/stabilizer to treat the heavy metal contaminated soil with improved strength. In this study, the red mud, a kind of solid waste material from the alumina factory, was added into the soil to form the compound solidifier/stabilizer with cement to treat the copper-contaminated soil. The mechanical characteristics of solidified/stabilized soil were analyzed systematically, as well as the microstructure by SEM, EDS, and XRD. Besides, the leaching toxicity of solidified/stabilized soil was also tested. The results show that the red mud residue compound solidifier/stabilizer exhibits a better solidification efficiency than the pure cement, and the copper leaching amount values are all far below the standard limit. In this study, the red mud residue content is proposed as 15–45%. As for the stress–strain relationship characteristic of solidified/stabilized soil, it would differ notably with copper concentration. In addition, the microscopic analyses support the hydration products of solidified/stabilized soil that are mainly composed of hydrated calcium silicate/calcium silicate aluminate hydrate, calcium carbonate, and ettringite, which can solidify/stabilize the copper ion and increase the unconfined compressive strength. Thus, the red mud waste has great potential to be popularized as a source applied in heavy metal treatment.
研究领域:
环境工程
·
岩土工程
·
环境化学
·
固体废物利用
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土壤修复
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2022
·
IF 14.224
Xing Cao,Qiushi Zhang,Weichen Yang,Lin Fang,Shiwei Liu,Rui Ma,Kai Guo,Ning Ma
The high chlorine (Cl) and lead (Pb) content characteristics of municipal solid waste incineration fly ash (MSWIFA) pose environmental risks and hinder resource utilization. Herein, an MSWIFA-based magnesium potassium phosphate cement (MKPC) preparation strategy was developed, which allowed the MSWIFA recycling and the Pb-Cl synergistic immobilization without the washing pretreatment . The compressive strength of the resulting 10 wt% MSWIFA-based MKPC was 28.44 MPa, with over 99.2% reduction in leaching toxicity of Pb and Cl. The high-angle annular dark field scanning transmission electron microscope (HAADF-STEM) and X-ray absorption spectroscopy (XAS) analyzes showed that Pb, phosphate and Cl - formed Pb 5 (PO 4 ) 3 Cl in MKPC. In-situ X-ray diffraction (XRD) tests showed that Pb 3 (PO 4 ) 2 was gradually transformed to Pb 5 (PO 4 ) 3 Cl through a dissolution-precipitation process. The formation energy, Bader charge, charge density difference and density of states (DOS) of Pb 5 (PO 4 ) 3 Cl were analyzed by first-principles calculations, confirming that Pb 5 (PO 4 ) 3 Cl was more thermodynamically stable than Pb 3 (PO 4 ) 2 and PbCl 2 and that electronic interactions between Pb-p, O-p, P-p and Cl-p orbits were the origin of Pb-Cl synergistic immobilization. This work provides a new strategy for the resource utilization of MSWIFA without washing pretreatment, and provides an in-depth understanding of the Pb-Cl synergistic immobilization mechanism.
研究领域:
环境科学
·
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2024
·
IF 7.4
Tao Huang,LuLu Zhou,Shuwen Zhang,Yuyang Qin,Zhengfeng Hu
In the face of escalating arsenic pollution and the mounting challenge of municipal solid waste incineration (MSWI) fly ashes, cutting-edge technology has emerged as a game-changer. By harnessing the power of MoS 2 nanosheets, a revolutionary approach to double-self-cementation has been unlocked, addressing the limitations of previous methods. Through heterogeneous adsorption, MoS 2 nanosheets bolstered the stability of the matrix, leading to a remarkable surge in compressive strengths and a substantial reduction in leaching toxicities of heavy metals. The compressive strengths of the cemented cubes increased as the dosage of nanosheets increased from 0.3 % to 2.4 %, with compressive strengths ranging from 24.34 to 34.21 MPa. The leaching toxicities of Zn, Cu, Cr, Cd, Pb, and As from the solidified matrix correspondingly decreased to 0.32, 0.21, 0.04, 0.01, 0.05, and 0.53 mg/L, respectively. The role played by nanosheets in inhibiting the release and transport of chloride species further underscored their pivotal contribution. Moreover, the study delved into the intricate mechanisms underlying the impact caused by nanoscale materials cementation and geopolymerization systems, shedding light on their dual function as solidification intensifiers and chemical stabilizers. The nanosheet-enhanced double-self process can be appropriately fitted by the JMAK model. The linear nuclei growth of gels controlled the solidification and geopolymerization of the precursor materials and the stabilization of HM contaminants. This groundbreaking research not only elucidates the transformative potential of MoS 2 nanosheets but also paves the way for a paradigm shift in the treatment of contaminated soils and waste materials.
研究领域:
环境科学
·
材料科学
·
化学工程
·
废物管理
·
土壤科学
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2022
·Vol. 29
·期 24
·36337-36350
·
IF 5.19
Wang Bing,Cao Qingtong,Li Guomin,Zhang Jian
Given that the biological treatment of antibiotic wastewater can easily induce resistant bacteria, the photocatalytic degradation of antibiotics is considered as a better method for treating antibiotic wastewater. Therefore, the ability to remove Tylosin (TYL) and Tetracycline (TC) in aqueous solution using rare earth element Tb-doped g-C 3 N 4 under simulated natural solar radiation was investigated. A series of rare earth Tb 3+ doped mesoporous g-C 3 N 4 were successfully prepared by nitric acid treatment and Tb(NO 3 ) 3 ·5H 2 O samples showed significantly higher degradation efficiency for TYL and TC than pure g-C 3 N 4 . Leaching toxicity experiments were carried out on the catalyst using chard seeds and demonstrated negligible toxicity of the leachate from the catalyst. The structure, elemental state, optical properties, morphology, and photogenerated carrier separation of the prepared xTCN catalysts were characterized by XRD, XPS, UV–Vis DRS, TEM, and PL. The results show that Tb doping enhanced the photocatalytic activity of the g-C 3 N 4 catalyst by narrowing the band gap while improving the light-trapping ability; The separation and transport rate of photogenerated carriers were significantly increased after Tb doping. Finally, a simple, efficient, and non-polluting Tb-doped carbon nitride photocatalyst is successfully developed in this paper.
研究领域:
环境科学
·
材料科学
·
化学
·
光催化
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）