ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Wanli Lian,Guanghui Yu,Jie Ma,Juan Xiong,Cuiyun Niu,Ran Zhang,Haijiao Xie,Liping Weng
Despite extensive study, geochemical modeling often fails to accurately predict lead (Pb) immobilization in environmental samples. This study employs the Charge Distribution MUlti-SIte Complexation (CD-MUSIC) model, X-ray absorption fine structure (XAFS), and density functional theory (DFT) to investigate mechanisms of phosphate (PO4) induced Pb immobilization on metal (hydr)oxides. The results reveal that PO4 mainly enhances bidentate-adsorbed Pb on goethite via electrostatic synergy at low PO4 concentrations. At relatively low pH (below 5.5) and elevated PO4 concentrations, the formation of the monodentate-O-sharing Pb-PO4 ternary structure on goethite becomes important. Precipitation of hydropyromorphite (Pb5(PO4)3OH) occurs at high pH and high concentrations of Pb and PO4, with an optimized log Ksp value of −82.02. The adjustment of log Ksp compared to that in the bulk solution allows for quantification of the overall Pb-PO4 precipitation enhanced by goethite. The CD-MUSIC model parameters for both the bidentate Pb complex and the monodentate-O-sharing Pb-PO4 ternary complex were optimized. The modeling results and parameters are further validated and specified with XAFS analysis and DFT calculations. This study provides quantitative molecular-level insights into the contributions of electrostatic enhancement, ternary complexation, and precipitation to phosphate-induced Pb immobilization on oxides, which will be helpful in resolving controversies regarding Pb distribution in environmental samples.
研究领域:
环境科学
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地球化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
·
2023
·
IF 6.1
Yongkui Li,Xianjin Qi,Guohua Li,Heng Wang,Guizhi Yan,Jiahao Shi
As-containing acidic wastewater from the nonferrous heavy smelting industry is a hazardous As pollution source due to its complex composition, high acidity, and strong toxicity. In this study, an environmentally friendly strategy was proposed to simultaneously remove and immobilize As from acidic wastewater through the synthesis of highly stable scorodite using natural magnetite ore as Fe resource. Firstly, the magnetite ore was dissolved in wastewater to provide a certain amount of starting Fe source for the subsequent arsenic precipitation while creating a suitable pH environment for the synthesis of scorodite. Subsequently, the released Fe ions reacted with As ions in wastewater with undissolved magnetite ore as the nuclear site to form amorphous ferric arsenate, which was then transformed into a well-crystallized scorodite precipitate, thus achieving the As removal and immobilization. Under the optimal reaction conditions, including a Fe/As molar ratio of 2.5, a pre-dissolution time of 5 h, an initial pH of 2.0, a reaction time of 24 h, and a reaction temperature of 90 °C, the residual As concentration in the wastewater rapidly reduced from initial 6259.00 mg/L to 3.76 mg/L, corresponding to an arsenic removal efficiency of 99.94%, and the leaching As concentration in scorodite was 0.42 mg/L. This study provides an efficient and environmentally friendly method for the disposal of high As-containing wastewater from nonferrous smelting.
研究领域:
环境科学
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化学工程
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产品关联
DOI
高影响因子
CHEMOSPHERE
·
2022
·
IF 8.943
Xiaofeng Jiang,Wenjun Long,Liangqiong Peng,Teng Xu,Faming He,Yuling Tang,Wenhua Zhang
The rapid reductive immobilization of Cr(VI) from the aqueous solution was achieved by reduction to Cr(III) using tannic acid (TA), and subsequent pH-triggering precipitation of the organo-Cr(III) complexes formed in the redox reaction. The effects of TA concentration, temperature, and solution pH on the reduction of Cr(VI) were examined by batch experiments, and the rapid redox reduction followed a second-order kinetics with respect to Cr(VI) concentration in the pH range of 2.0–3.0. UV–visible spectra, FTIR, and XPS confirmed the complete detoxification of Cr(VI) concomitant with carboxylation of partial phenolic hydroxyls in TA. Synchronously, the reduced Cr(III) coordinated with carboxyl groups in oxidized TA (OTA) to form complexes, which exhibited remarkable pH-dependent size distribution characteristics as illustrated by SEM images and sequential filtration/ultrafiltration. The resulted Cr(III) complexes could aggregate into colloids with larger size and precipitate out at pH range of 6.0–8.0 via cross-linking, thereby leading to 93% Cr and 89% TOC immobilization. An eco-friendly and cost-effective method for Cr(VI) elimination and immobilization is provided because polyphenols are natural polymers derived from plants.
研究领域:
环境科学
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化学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2023
·
IF 13.6
Junpeng Li,Rui Bai,Wei Chen,Chongyuan Ren,Fan Yang,Xiaochun Tian,Xiaofeng Xiao,Feng Zhao
Mineralization of lead ions (Pb 2+ ) to pyromorphite using phosphorus-containing materials is an effective way to remediate lead (Pb) contamination. Bone char is rich in phosphorus, but its immobilization of Pb 2+ is limited by poor phosphate release. To utilize the phosphorus in bone char and provide a suitable growth environment for phosphate-solubilizing bacteria, bone char and Pseudomonas rhodesiae HP-7 were encapsulated into bio-beads, and the immobilization performance and mechanism of Pb in solution and soil by bio-beads were investigated. The results showed that 137 mg/g of phosphorus was released from bone char in the presence of the HP-7 strain. Pb 2+ removal efficiency reached 100 % with an initial Pb 2+ concentration of 1 mM, bone char content of 6 g/L, and bio-bead dosage of 1 %. Most Pb 2+ was immobilized on the surface of the bio-beads as Pb 5 (PO 4 ) 3 Cl. The soil remediation experiments showed a 34 % reduction in the acid-soluble fraction of Pb. The bio-beads showed good stability in long-term (30 d) soil remediation. The present study shows that bone char can be turned into an efficient Pb immobilization material in the presence of phosphate-solubilizing bacteria. Thus, bio-beads are expected to be used in the remediation of Pb-contaminated environments.
研究领域:
环境科学
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微生物学
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产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Yanlin Chen,Qingyan Zhang,Xijun Fu,Shuaishuai Guo,Qingyi Zeng
Hydroxyapatite (HAP) has been recognized as an effective absorbent for uranium. Recognizing and revealing its fate in coordinating with uranyl ions (U(VI)) under various conditions are vital for its practical application. In this work, HAP nanoflowers were synthesized by a simple wet chemical method, and the immobilization properties of HAP on U(VI) and U(VI) phase transformation during immobilization process were investigated systematically using a host of experimental methods and advanced characterization techniques. The results show that HAP can effectively immobilize U(VI) at high concentrations (50–3000 mg/L), with a maximum U(VI) adsorption capacity (q) of 10,200 mg/g and a distribution ratio (K d ) higher than 1.16 × 10 5 mL/g. Under the presence of sufficient U(VI) and a pH around 1.5 ∼ 3.0, HAP can rapidly react with U(VI) to form Autunite (Ca(UO 2 ) 2 (PO 4 ) 2 ·3H 2 O) with a nanoflake morphology, which is demonstrated excellently long-term stability. A moderately low pH that enables form adequately free calcium ions and phosphate groups via hydrolysis of HAP is essential to the mineralization of U(VI). This work is expected to pave the way for the use of HAP to develop highly efficient immobilization agents for the remediation of uranium-contaminated scenes and presents a comprehensive insight into the mechanisms of long-term U(VI) stabilization.
研究领域:
环境科学
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材料科学
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产品关联
DOI
高影响因子
JOURNAL OF CONTAMINANT HYDROLOGY
·
2024
·
IF 3.5
Yuting Song,Hongyan Deng,Wenbin Li,Shuni Zhou,Xin Liu
To study the pollutants immobilization and economy of biologically amended coastal soil , Alternanthera philoxeroides biomass (Bm), biochar (Bc), and dodecyldimethyl betaine (BS) modified Bc (BS-Bc) were used to amend coastal soil from Jialing, Fu, and Qu River. A runoff experiment was used to simulate the longitudinal migration and morphological changes of Pb(II) and chlortetracycline (CTC) in each amended coastal soil, and the economy of pollutants immobilization by different amended coastal soil were compared. The equilibrium time of Pb(II) and CTC in each amended coastal soil ranked in the order of BS-Bc-amended > Bc-amended > Bm-amended > unamended coastal soil. The average Pb(II) and CTC flow rate in different amended coastal soils presented an opposite trend with the equilibrium time. Pb(II) and CTC content all reduced with the increasing runoff length. Under the same soils, the content changes presented Bm and Bc amended > unamended > BS-Bc amended. CEC and clay content of coastal soils were the key factors affecting Pb(II) and CTC immobilization. The immobilization mechanisms were electrostatic attraction, ion exchange, surface precipitation, and complexation to Pb(II) and ion exchange and complexation to CTC. The economy of Pb(II) and CTC immobilization ranged from 0.5 to 9.0 and from 1.0 to 5.4 mg/¥, and coastal soil amended by BS-Bc had practical application value and high economy.
研究领域:
环境科学
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生物学
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产品关联
DOI
PubMed
高影响因子
MONATSHEFTE FUR CHEMIE
·
2019
·Vol. 150
·期 7
·1349-1354
·
IF 1.501
Li Yunhao,Liu Shiquan
Abstract A porous silica gel with both COOH and NH 2 groups was synthesized in one pot by the addition of l -glutamic acid ( l -GA) into a synthesis medium consisting of tetraethyl orthosilicate, water, ethanol, and 1-butylamine. The inclusion of l -GA in the as-synthesized product ( l -GA-SiO 2 ) was evidenced by FT-IR and TG measurements. The l -GA was chemically bonded with silica as indicated by the shift of FT-IR bands at 1510 and 1400 cm −1 in the spectrum of l -GA to higher wavenumbers of 1540 and 1460 cm −1 in the one of l -GA-SiO 2 . The TG analysis showed that the l -GA-SiO 2 had an increase of weight loss by 5.6% due to the decomposition of the included l -GA which was centered at around 313 °C, suggested by a new peak in the DTG curve. Compared with the one synthesized without l -GA, the l -GA-SiO 2 was more aggregated with smaller surface area. However, the latter showed a higher removal efficiency by 17.1% toward zinc ions in water than the former and the adsorbed ions were hardly released again into water from the used adsorbent. Graphical abstract
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Junping Shi,Lielin Wang,Hua Xie,Shidi Yao,Xiuqi Pu,Zhu Liu,Xiaojiang Chen,Yun Ding
Highly reactive fission product cesium may volatilize at high temperatures. PbO–B 2 O 3 –ZnO glass with low melting temperature and excellent chemical durability can be used as a potential matrix for immobilizing Cs. In this work, five PbO–B 2 O 3 –ZnO glasses with different contents of Pb were synthesized via a melt-quenching process. These specimens were characterized with XRD , Raman, DTA and viscosity measurements . The results showed that the melting temperature decreases, viscosity decreases and structural polymerization increases with increasing lead content. Cs-doped 35PbO–60B 2 O 3 –5ZnO glasses were synthesized at low temperatures. XRD results revealed the amorphous nature of the glass solidified bodies. EDS and ICP-MS studies confirmed that Cs is retained in the glass. Clear vitrified waste products containing up to 13.6 wt% Cs were obtained. The chemical durability of the samples was evaluated via PCT-A and MCC-1 method. For the glass solidified body comprising a Cs/matrix ratio of 0.136, the leaching rate of Cs was 1.6 × 10 −1 g m −2 d −1 from the PCT test, which indicates that it has a good chemical stability. 35PbO–60B 2 O 3 –5ZnO glass was expected to be a suitable matrix for Cs immobilization.
研究领域:
材料科学
·
核废料管理
✓ 已验证
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Gongting Wang,Zedong Teng,Ziyi Wei,Xin Zhao,Wenqing Luo,Yuxin Cheng,Yali Guo,Xiaonan Ji,Wei Hu,Min Li
The serious contamination of cadmium (Cd) in sediments has become an urgent environmental problem. Quinones mediated dissimilatory iron and manganese reduction widely occurs in sediments, this process may enhance Cd immobilization by promoting production of secondary minerals. Nevertheless, the enhancing effect of Cd immobilization is still poorly understood. Here, 9,10-anthraquinone-2,6-disulfonic acid (AQDS) was used to facilitate the microbial reduction of iron and manganese oxides by Geobacter metallireducens GS-15, and its effects on Cd species was investigated. Compared to goethite (FeOOH), microorganisms preferentially reduced birnessite (MnO 2 ) due to more dramatic interfacial electron transfer between birnessite and AQDS. AQDS thus significantly enhanced microbial reduction of iron and manganese coexisted minerals as well as Cd 2+ immobilization. After 80 days, an impressive 83% of reducible-Cd appeared in the FeOOH–MnO 2 -AQDS group, demonstrating the most effective Cd immobilization. Furthermore, XANES results suggested that AQDS promoted the increase of vivianite-Cd in secondary minerals in MnO 2 -AQDS and FeOOH–MnO 2 -AQDS groups. Based on the structural equation model, HCl-extracted Fe(II) indirectly affected the increase of reducible-Cd mainly through vivianite-Cd. The AQDS enhancement on microbial reduction of iron and manganese oxides promotes the recrystallization of secondary minerals and the immobilization of Cd, offering a promising strategy for the remediation of Cd-contaminated sediments.
研究领域:
环境科学
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微生物学
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产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Jieling Ren,Yuanzhe Peng,Aibin Zhu,Chunli Zheng,Chi He,Mudi Ma
Kaolinite-loaded amorphous zero-valent iron composite (K@AZVI) is a promising material for cadmium-contaminated soil remediation. Still, the impact of iron (Fe) oxides on the surface of K@AZVI on the immobilization of cadmium (Cd) in soils caused by varying water management remains unclear. Hence, this study investigated the transformation of Fe oxides in K@AZVI and their effects on Cd morphology under varying soil water management (drying, wetting, and flooding). The results indicated that under K@AZVI treatment, the pe + pH (pe = Eh (oxidation-reduction potential, mV) / 59.2) values decreased from 11.59 to 9.83 and 5.61 with increased soil water management. Meanwhile, the content of crystalline Fe oxides (Fe c ) decreased significantly by 34.02%-72.76%, while the content of amorphous Fe oxides (Fe o ) increased by 29.01%-55.20%. This transformation from crystalline to amorphous Fe oxides significantly enhanced the immobilization of Cd, resulting in a 30.30%-64.59% reduction in the available Cd content compared to the control. In addition, the proportion of low active Cd was enhanced from 32.94% to 56.10%, further indicating that K@AZVI exhibited superior immobilization in flooded soil. Characterization and calculations showed that water management significantly improved the immobilization of Cd by K@AZVI by regulating the crystallinity of Fe oxides and enhancing their electron transfer rate and adsorption capacity. Therefore, investigating the morphological transformation of Fe under varying water management will help us to understand the mechanism of Fe redox-mediated Cd transport and transformation in the soil system.
研究领域:
环境科学
·
土壤学
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DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Maolin Wang,Canyang Hu,Jiahui Xu,Xudong Jing,Hafeez Ur Rahim,Xiyun Cai
Cadmium (Cd) is one of the most toxic substances released in the environment. Cd-contaminated soils usually have a large pool of bioavailable Cd species and lead to excessive Cd accumulation in planted cereal crops. Treatment methods for stable immobilization of Cd in soils are desirable. Here we reported that facile combinations of thiosulfate (STS) and zerovalent iron (ZVI) reinforced Cd immobilization in soils and reduced Cd accumulation in wheat. STS mildly activated Cd in soils through the formation of soluble Cd(S 2 O 3 ) x complexes, whereas intermediates of STS (e.g., sulfate and sulfides) and ZVI synergically facilitated immobilization of Cd in soils. The synergy was ascribed to the facilitated formation of FeOOH with high Cd-binding affinity and formation of stable sulfate-Cd-FeOOH complexes and poorly available CdS x . STS-ZVI treatments increased residual Cd in soils by 101–123% and decreased Cd accumulation in wheat shoots by 13–68%, depending on chemical compositions and doses of binary reagents. Field applications of STS and ZVI (0.06–0.11 kg/m 2 ) demonstrated 24–39% reductions of grain Cd.
研究领域:
环境科学
·
农业科学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC
·
2013
·
IF 2.823
Huaping Dong,Yimin Li,Guodong Sheng,Liujiang Hu
Three different functionalized bentonites including acid activated bentonite ( B a ), organically modified bentonite with cetyltrimethyl ammonium bromide ( B CTMAB ) and the composite by acid activation and organo-modification ( B a-CTMAB ) were prepared, and used for immobilization of lipase from bovine pancreatic lipase by adsorption. The amount of lipase adsorbed on the functionalized bentonites was in the following sequence: B a > B CTMAB > B a-CTMAB , showing the strongest affinity of B a for lipase among the three supports. However, the immobilized lipase on B a-CTMAB showed the highest activity in the hydrolysis of olive oil by 1.67 times of activity of free lipase due to the hydrophobically interfacial activation and enlarged catalytic interface. While, the activity of immobilized lipase on B a was lower than 20% of free lipase’s activity due to the absence of hydrophobic activation and negative impact of excessive hydrogen ions on the surface. The K m values for the immobilized lipase on B a-CTMAB (0.054 g/mL) and B CTMAB (0.074 g/mL) were both lower than that of free lipase (0.115 g/mL), and the V max values were higher for the immobilized lipases, exhibiting a higher affinity of the immobilized lipase toward olive oil than free lipase. In comparison to free lipase, the better resistance to heating inactivation, storage stability and reusability of the immobilized lipases on B a-CTMAB and B CTMAB were also obtained. The results show that the efficient and stable biocatalysts for industrial application can be prepared by using the low-cost bentonite mineral as the supports.
研究领域:
生物化学
·
酶工程
·
材料科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）