SCIENCE OF THE TOTAL ENVIRONMENT
·
2020
·
IF 6.551
Minhua Su,Zequan Liu,Gutha Yuvaraja,Tao Ou,Ying Huang,Xiaoting Hu,Diyun Chen
Contamination caused by radionuclides such as uranium (U) has become an increasingly serious environmental problem. The unique and diverse features of uranyl ions (U(VI)) remarkably dominate their mobility and environmental impact on the ecosystem. Understanding the sorption behavior and fate of aqueous U(VI) ions on natural mineral(s) such as quartz sand (a typical type of crystalline silica (SiO 2 )) particles is essential for unraveling many environmental issues . In this work, the sorption of uranyl ions by various particle size quartz sands under different reaction conditions was thoroughly investigated. The quartz sand with an average particle size of 3.588 μm exhibited an excellent sorption performance for the removal of aqueous U(VI) ions at pH 5.0. The sorption rate increased as the dosage of sorbent increased. The sorption rate descends with the rise of the initial U(VI) concentration while its sorption amount is reversed. The elevation of temperature impeded the U(VI) sorption. Humic acid (a typical natural organic matter) showed significant impacts on U(VI) removal. Ions of Ca 2+ , CO 3 2− and K + remarkably inhibited the U(VI) sorption, while PO 4 3− ions significantly promoted the U(VI) sorption. The pseudo second-order kinetic model could fit well with the experimental sorption data. The U(VI) sorption is mainly chemisorption and it is an exothermic process. After sorption, the surface of used quartz sand became much smooth and XPS signals of U(VI) were detected, evidencing the success of the removal of aqueous U(VI). The outcomes of this study highlighted both solution pH and natural organic matters played critical roles on U(VI) removal by sand particles. This study further enhances our comprehension from the molecular-scale process manipulating U(VI) sorption behavior at the mineral-aqueous interface.
研究领域:
环境科学
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放射化学
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产品关联
DOI
PubMed
高影响因子
PHOTOCHEMICAL & PHOTOBIOLOGICAL SCIENCES
·
2016
·Vol. 15
·期 8
·1046-1053
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IF 2.235
Zhang Guangshan,Wang Qiao,Zhang Wen,Li Tian,Yuan Yixing,Wang Peng
This work investigated the effects of organic acids and initial solution pH on the photodegradation of BPA in a photo-Fenton-like process using α-FeOOH as a catalyst. The results showed that the addition of different organic acids affected the formation of the ferric-carboxylate complexes and free radicals, which in turn varied the photodegradation efficacy. Compared with the other acids, oxalic acid (OA) was found to be the most effective in enhancing the photodegradation of BPA, which strongly depends on the OA concentration. Particularly, the addition of OA could significantly extend the working pH from an acidic to a neutral range for the photocatalytic process and thus the acidification pretreatment may not be needed. A high photocatalytic degradation of BPA occurred at pH 6.0, due to the formation of ferric-oxalate complexes and ˙OH radicals in the synergistic interactions of OA and α-FeOOH. This finding highlights that the oxalate-promoted photo-Fenton-like process using the α-FeOOH catalyst may be used for wastewater treatment without pH adjustment.
研究领域:
环境科学
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化学工程
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DOI
PubMed
高影响因子
JOURNAL OF CHEMICAL TECHNOLOGY AND BIOTECHNOLOGY
·
2015
·Vol. 91
·期 4
·985-993
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IF 2.349
Jiang Lu,Xiaodan Wei,Yu Chang,Shuanghong Tian,Ya Xiong
BACKGROUND An ozonation catalyst needs to be recycled easily and to exhibit high activity in view of its practical application in wastewater treatment. In this study, magnetic mesoporous MgFe 2 O 4 was successfully prepared and used as a new ozonation catalyst for degradation of Acid Orange II (AOII). The role of Mg in MgFe 2 O 4 was revealed to explain the high activity by catalytic experiments and XPS analysis. RESULTS The degradation efficiency of AOII in the MgFe 2 O 4 /O 3 process exceeds 90% over a wide pH range of 4.6–9.6, slightly affected by the solution pH. The catalytic activity of MgFe 2 O 4 is much higher than that of MgO, Fe 2 O 3 and also their mixture (MgO+Fe 2 O 3 ) with identical molar ratio of Mg 2+ to Fe 3+ , indicating the first role of Mg, i.e. coupling with Fe to present a synergistically catalytic effect. Furthermore, MgFe 2 O 4 possesses a reaction rate constant at least 2.3 times that of NiFe 2 O 4 , MnFe 2 O 4 , and CuFe 2 O 4 . It illustrates the second role of Mg, i.e. causing the high electron density on lattice oxygen in MgFe 2 O 4 indicated by XPS and thus favoring activation of the electrophilic ozone. CONCLUSIONS This study demonstrated the easy recycling and high activity of MgFe 2 O 4 in catalytic ozonation, and revealed the role of Mg in MgFe 2 O 4 . © 2015 Society of Chemical Industry
研究领域:
环境科学
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催化材料
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DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Bingxin Yuan,Meiting Li,Chi Zhang
BiOCl micro/nanoplates and their hierarchical architectures were selectively synthesized via 24 h of hydrothermal reaction at 180 °C and a wide range of solution pH (2–12), where the vital role of solution pH in phase/morphology evolution were elaborated from solution chemistry and crystal facet engineering. It was unambiguously demonstrated that a higher solution pH retarded the binding interaction between H + and oxygen-terminated {001} facets, and also yielded more oxygen vacancies. Therefore, the ab -dominated hierarchical self-assembly was the result. Analysis of photocatalytic properties further manifested that the significant exposure of ab plane is beneficial to photocatalysis. The best pH = 10 catalyst showed the strongest UV absorption, ∼98.5 % of removal efficiency toward the methyl orange molecules within 20 min of simulated solar light irradiation and favorable reusability, while the values are only ∼55.21 % and 50.75 % for the pH = 2 and pH = 12 ones, respectively. This systematic study facilitates a better understanding of photoreaction mechanism of the compound by considering oxygen vacancy defects and electron-hole interaction.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2017
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IF 3.359
Ying Zhang,Ting-An Zhang,David Dreisinger,Weihua Zhou,Feng Xie,Guozhi Lv,Weiguang Zhang
In the current study, a novel chelating extractant Mextral 973H was employed to selectively extract V(V) from a low pH sulfuric acid solution containing high concentration of Fe (Ш). The extraction of V(V) is strongly dependent on solution pH, and the separation coefficient (β (V/Fe) ) between V(V) and Fe(Ш) can be greater than 720 when the solution pH < 0.5. A cation exchange between H and VO 2 + was proposed as the main extraction mechanism at pH < 1.5, while at pH > 1.5, a solvating reaction between the extractant and metal-oxo cluster anions took place. The effects of solution pH, acid medium types, contacting time and temperatures on the extraction and separation of V have been discussed. FT-IR and 1 HNMR were applied to confirm the extraction mechanism and also the degradation behavior of Mextral 973H in some extreme conditions. The loaded vanadium was effectively stripped using a diluted 0.2 M Na 2 CO 3 solution and a total stripping extent of 97% was achieved. The extraction process by Mextral 973H was finally simulated using Aspen Plus simulator comparing to traditional process, the results obtained were in good recovery efficiency and with the advantage of acid and alkali saving.
研究领域:
化学工程
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环境科学
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
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IF 3.99
Haojing Zhang,Taotao Lu,Mengjie Wang,Ruixia Jin,Yumeng Song,Yanmei Zhou,Zhichong Qi,Weifeng Chen
Biochar, a cost-effective carbonaceous material , has shown great promise in many applications such as soil remediation and wastewater treatment . Citric acid in soil and water environments may affect interactions between biochar and organic contaminants (e.g., tetracycline). To evaluate the effect of citric acid on the adsorption of tetracycline onto biochars, this study investigated the adsorption behavior of tetracycline onto biochars of two different pyrolysis temperatures (300 and 450 °C, referred to as BC_300 and BC_450) in the present of citric acid, accompanying with the effects of solution pH and Cu 2+ . The results indicated that citric acid significantly inhibited the adsorption of tetracycline onto both biochars, that was mainly due to the multi-mechanisms including pore blocking effect, surface adsorption sites competition, and steric hindrance induced by citric acid. Moreover, citric acid more significantly suppressed the adsorption of tetracycline onto the two biochars at pH 9.0 than at pH 5.0 and 7.0. Because increasing pH could promote electrostatic repulsion between the negative tetracycline and the negatively charged surface of biochars. Cu 2+ had greater enhancing effect on the sorption of tetracycline onto BC_300 than BC_450 via cation-bridging effect. Meanwhile, citric acid inhibited the adsorption of tetracycline onto BC_300 to a larger extent than the adsorption onto BC_450 in the presence of Cu 2+ . That is possibly due to BC_300 has more surface oxygen-containing functional groups than BC_450. Thus, the effect of coexisting citric acid needs to be taken into account when biochar is increasingly used as an amendment in soil and water systems.
研究领域:
环境科学
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土壤学
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水处理工程
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产品关联
DOI
高影响因子
Environmental Science-Processes & Impacts
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2022
·Vol. 24
·期 7
·1071-1081
·
IF 5.334
Qiqi Wei,Qiang Zhang,Yihan Jin,Usman Farooq,Weifeng Chen,Taotao Lu,Deliang Li,Zhichong Qi
To date, there is still very little knowledge about the combined effects of typical inorganic ligands and solution pH values on mobility characteristics of tetracycline (TC) through saturated aquifer media. In this work, three typical inorganic ligands (i.e., phosphate, silicate, and iodate) were employed in the transport experiments. Generally, all the ligands promoted TC mobility over the pH range of 5.0–9.0 owing to the enhanced electrostatic repulsion between sand grains and TC anionic forms (i.e., TC− and TC2−) as well as the competitive deposition between ligands and antibiotic molecules for attachment sites. Furthermore, the transport-enhancement effects of ligands on TC intensively depended on ligand type and followed the sequence of phosphate > silicate > iodate. This phenomenon was ascribed to their different molecular sizes and binding abilities to sand grains. Interestingly, the differences in extents of enhanced effects of various inorganic ligands on TC transport varied with background solution pH due to pH-induced different extents of deposition site competition effects. Moreover, the two-site nonequilibrium model (which accounts for an equilibrium site and a kinetic site) as well as adsorption and kinetic studies were performed to help interpret the controlling mechanisms for the synergistic effects of inorganic ligands and solution pH on TC transport in saturated quartz sand. The findings of our study clearly demonstrate that inorganic ligands may be critical factors in assessing the fate and transport of antibiotics in groundwater systems.
研究领域:
环境科学
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土壤学
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产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2024
·
IF 12.2
Peng Zhang,Minglu Sun,Juan Liang,Zhaokun Xiong,Yang Liu,Jiali Peng,Yue Yuan,Heng Zhang,Peng Zhou,Bo Lai
Solution pH is one of the primary factors affecting the efficiency of water decontamination . Although the influence of pH on oxidants activation, catalyst activity, and reactive oxygen species have been widely explored, there is still a scarcity of systemic studies on the changes in the oxidation behavior of organic pollutants at different pH levels. Herein, we report the influence laws of pH on the forms, reactivities, active sites, degradation pathways, and products toxicities of organic pollutants. Changes in pH cause the protonation or deprotonation of organic pollutants and further affect their forms and chemistry (e.g., electrostatic force , hydrophobicity , and oxidation potential). The oxidation potential of organic pollutants follows the order: protonated form > pristine form > deprotonated form. Moreover, protonation or deprotonation can modify the active sites and degradation pathways of organic pollutants, wherein deprotonation renders them more susceptible to electrophilic attack, while protonation reduces their activity against electrophilic and nucleophilic attacks. Additionally, pH adjustments can modify the degradation pathway and the toxicity of transformation products. Overall, pH changes can affect the oxidation fate of organic pollutants by altering their structure, which distinguishes it from the effect of pH on oxidants or oxidant activation processes.
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
·
2020
·
IF 9.038
Shuai Tang,Lujian Lin,Xuesong Wang,Anqi Yu,Xuan Sun
In water environments, nylon microplastics (MPs) and heavy metals are two kinds of common pollutants. This study investigated the adsorption of three divalent metals (Cu(II), Ni(II), Zn(II)) onto collected nylon MPs as function of contact time, temperature, solution pH, ionic strength and concentration of fulvic acid (FA). The kinetic data fitted well with the Elovich and pseudo-second order equations. The result of shrinking core model (SCM) confirms that the adsorption of Cu(II) and Zn(II) was mainly controlled by intraparticle diffusion. The adsorption of three metal ions onto collected nylon MPs is spontaneous, endothermic, with an increased randomness in nature. The Langmuir and Freundlich models successfully described the adsorption isotherms. The speciation distributions of three divalent metals in aqueous solutions were identified to analyze the effects of initial solution pH, ionic strength and fulvic acid concentrations on the adsorption amounts. X-ray photoelectron spectroscopy (XPS) analysis indicates the importance of surface O-containing groups of collected nylon MPs in controlling the adsorption of three metal ions. This research provides a clear theoretical basis for the behavior of nylon MPs as heavy metals (Cu(II), Ni(II), Zn(II)) carrier and highlights their environmental toxicity, which deserves to be further concerned.
研究领域:
环境科学
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化学
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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2017
·
IF 3.615
Yu Liu,Zimo Lou,Yue Sun,Xiaoxin Zhou,Shams Ali Baig,Xinhua Xu
In this study, SiO 2 -EDTA was prepared by silanization reaction between N-(trimethoxysilylpropyl) ethylenediamine triacetic acid, trisodium salt (EDTA-silane) and hydroxyl groups for enhanced removal of Pb(II), Pb(II)-Cit (the clathrate generated by Pb(II) and trisodium citrate dehydrate(Cit)) and Pb(II)-EDTA(20%) from aqueous solutions. SiO 2 -EDTA composites were characterized using SEM, TEM, EDX-mapping, FTIR, XPS and TGA analyses. The influence of solution pH, initial concentration, contact time and co-existing interferents were also studied. Results demonstrated that the composite successfully adsorbed 147.52, 107.65 and 124.18 mg g −1 of Pb(II), Pb(II)-Cit, and Pb(II)-EDTA (20%), respectively with the initial Pb(II) concentration of 100 mg L −1 . Kinetics study revealed that the adsorption rate was significantly high at the beginning and then reached to equilibrium within 1.0 h. Moreover, Pb(II) adsorption capacities were found to considerably affected by co-existing cations and not inhibited by natural organic matter (NOM). Characterization analyses confirmed that EDTA was successfully assembled on SiO 2 which had been used as a supporting matrix due to its huge specific surface area. Findings from this study suggested that the present composite could be considered as a promising adsorbent for large scale treatment of wastewater containing elevated Pb(II) concentration.
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
DESALINATION
·
2018
·
IF 6.603
Jiaqi Huang,Shu Xiong,Qingwu Long,Liang Shen,Yan Wang
Proper draw solution is a crucial factor to generate a high performance in FO process. In this study, a phytic acid and its salt (PA-Na) were evaluated as novel draw solutes in FO process. The effects of the solution pH and concentration on the physicochemical properties were investigated systematically. Using 0.45 M PA-Na draw solution (pH = 7) and DI water feed solution, a relative high water flux of 19.02 LMH and a low solute flux of 0.51 gMH can be obtained, with HTI-TFC membrane in the PRO mode. An even better performance of a 30.35 LMH water flux and a 0.61 gMH solute flux can be achieved using the self-made HPAN-TFC membrane. The comparison of PA-Na and NaCl draw solutions shows that PA-Na draw solution has a much lower draw solute leakage and a competitive water flux. In addition, the application of PA-Na draw solution for the brackish water desalination was explored. The diluted PA-Na draw solution after FO may be used directly in food production by further dilution. In general, the non-toxicity and satisfactory FO performance of this food additive demonstrate its great potential as a draw solute for FO applications.
研究领域:
食品科学
·
环境工程
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
·
2024
·
IF 10.8
Yang Zhou,Zhu Zeng,Junhao Fu,Yuan Gao,Jinxing Ma,Zhong Zhang,Daoyuan Zu,Bin Han,Xixin Lu,Jun Ma,Jin Jiang
Humic acid (HA) ubiquitously existing in aquatic environments has been reported to significantly impact permanganate (KMnO4) decontamination processes. However, the underlying mechanism of the KMnO4/HA system remained elusive. In this study, an enhancing effect of HA on the KMnO4 oxidation of diclofenac (DCF) was observed over a wide solution pH range of 5–9. Surprisingly, the mechanism of HA-induced enhancement varied with solution pH. Quenching and chemical probing experiments revealed that manganese intermediates (Mn(III)-HA and MnO2) were responsible for the enhancement under acidic conditions but not under neutral and alkaline conditions. By combining KMnO4 decomposition, galvanic oxidation process experiments, electrochemical tests, and FTIR and XPS analysis, it was interestingly found that HA could effectively mediate the electron transfer from DCF to KMnO4 in neutral and alkaline solutions, which was reported for the first time. The formation of an organic–catalyst complex (i.e., HA-DCF) with lower reduction potential than the parent DCF was proposed to be responsible for the accelerated electron transfer from DCF to KMnO4. This electron transfer likely occurred within the complex molecule formed through the interaction between HA-DCF and KMnO4 (i.e., HA-DCF-KMnO4). These results will help us gain a more comprehensive understanding of the role of HA in the KMnO4 oxidation processes.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
PubMed
高影响因子
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