INTERNATIONAL JOURNAL OF ENVIRONMENTAL ANALYTICAL CHEMISTRY
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2023
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IF 2.6
Shifeng Li,Wenbo Sun,Yang Guo,Shuhua Yao,Zhongliang Shi,Haibo Wang
Batch test was conducted to investigate Se(VI) removal by nano zero-valent iron supported on biochar (BC@nZVI) prepared by a one-step carbothermal synthesis in the presence of ferrous ions and limited aeration. The presence of ZVI and biochar was confirmed in the synthesised material by X-ray diffraction and Raman spectroscopy. TEM analysis revealed that nZVI with a diameter of about 50 nm was dispersed well on the biochar. The Effects of BC@nZVI dosage, initial solution pH, Fe2+ concentration, limited aeration, and coexisting anions on Se(Ⅵ) removal were investigated. The role of Fe2+ on Se(VI) removal have been examined by sequential Fe2+ and Se(VI) dosing tests. More than 98% of Se(VI) (10 mg/L) was removed with BC@nZVI dosage of 1.0 g/L at pH 4.0. The removal percentage of Se(VI) decreased with an increasing in pH from 4.0 to 9.0. The strong electrostatic attraction between Se(VI) and nZVI and the high nZVI activity at low pH are responsible for the significant selenium removal. The removal efficiency of Se(VI) increased with increasing Fe2+ concentration from 0 to 0.5 mmol/L. Fe2+ promotes a shift in the passive layer on nZVI surface towards a medium that favours electron transfer. Se(VI) reduction by ZVI is thought to be accelerated under limited aeration. The positive effect of O2 on selenate reduction can be attributed either to mechanical removal of the oxide layer on the ZVI particles, or to a difference in electron transfer rates, or to a reactive Fe(II)-bearing solid formed when ZVI was oxidised by O2. Cl−, NO3−, SO42− and HA can inhibit the removal of Se(VI) on BC@nZVI in different degrees. The results of XRD, Raman, and XPS characterisation showed that the removal mechanism of Se(VI) include the adsorption and reduction ed of Se(VI) on BC@nZVI. Fe2+ and limited aeration would play a critical role in Se(VI) removal by BC@nZVI.
研究领域:
环境科学
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材料科学
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DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2016
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IF 2.76
Binbin Shao,Yiyi Guan,Zeyuan Tian,Xiaohong Guan,Deli Wu
Structural Fe(II) Hydroxide (SFH) was used to remove As(III) and As(V) from aerated synthetic wastewater with initially 30 mg/L As at neutral pH values. Batch experiments were performed to investigate the influence of O 2 , pH and coexisting HPO 4 2⿿ on As removal by 0.5 g (Fe)/L SFH. The results suggested that removal efficiency for As(III) and As(V) were ⿼60% and ⿼50% under anoxic conditions at initial pH 7.0 and 9.0, respectively. However, the efficiency increased to over 90% for both As(III) and As(V) under oxic conditions. The in situ mineral transformation of SFH to newly formed Fe(II/III) and FeOOH was responsible for the robust removal. As(III) removal was nearly unaffected by HPO 4 2⿿ (1.0 mM), while obviously inhibition was observed in the case of As(V). The microstructure of fresh and reacted SFH was characterized by FTIR and XPS and these results indicate that As was removed via inner-sphere complexation and precipitation. XPS studies showed that As(III) was converted to As(V) after 2 h of reaction in the pH range of 7.0⿿9.0, which is attributable to enhanced formation of Fe(IV) by the Fenton reaction during mineral transformation. In practice, results of this study suggest that aeration is advantageous to significantly enhancement of As(III) oxidation and removal with highly reactive SFH.
研究领域:
环境科学
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水处理工程
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DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
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2019
·Vol. 30
·期 16
·14869-14877
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IF 2.195
Zhang Yiqun,Dong Yaqiang,Liu Lei,Chang Liang,Zhou Bang,Chi Qiang,Wang Xinmin
A high-filling alumina/epoxy nanocomposite with improved thermal stability and insulation performance has been successfully designed as an organic–inorganic coating layer for the toroid-shaped FeSiBPNbCr amorphous magnetic powder cores (AMPCs). Unlike the organic coating, the organic–inorganic hybrid coating cores exhibited superior magnetic properties without compromising on saturation magnetization and permeability. The core loss declined by 40%, and the quality factor was 13% higher as half alumina was introduced into the epoxy resin matrix. A thin and uniform-coating layer of alumina/epoxy nanocomposite led to better high-frequency characteristics than those obtained with direct coating of the cores with alumina. Besides the outstanding magnetic properties, the Fe-based AMPCs with a convenient insulation-coating process cost lesser than Fe–Ni magnetic powder cores, thereby rendering the Fe-based AMPCs a potential candidate for a variety of industrial applications.
研究领域:
材料科学
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电磁学
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DOI
高影响因子
JOURNAL OF HYDROLOGY
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2023
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IF 6.4
Yanting Zhang,Na Zhang,Chenglong Yu,Hui Liu,Songhu Yuan
Production of reactive oxygen species (ROS), such as hydrogen peroxide (H 2 O 2 ) and hydroxyl radical (•OH), has been increasingly discovered upon oxygenation of reduced species in anoxic soil and sediment pore waters. We therefore hypothesize that H 2 O 2 and •OH can be produced during groundwater abstraction and discharging due to oxygenation. To evaluate the capacities of H 2 O 2 and •OH accumulation during groundwater oxygenation, here we measured H 2 O 2 and •OH accumulations during dark oxygenation of groundwater abstracted from different depths of 11 wells adjacent to the Han River. This abstraction could simulate the scenarios of groundwater abstraction by riverside pumping and also of groundwater discharging in hyporheic zones. Results showed that H 2 O 2 and •OH formed during oxygenation of the groundwater with low Eh values (< 63 mV), and only H 2 O 2 (< 3.37 μM) formed for the groundwater with high Eh values (63–206.5 mV). Statistical analysis indicated that dissolved Fe(II) was mainly accountable for the production of measurable •OH in the low Eh locations. The aquifer conditions (i.e., aquifer lithology) and external environmental factors (i.e. pumping disturbance) within short-term abstraction process had negligible influence on ROS production. The relationship between ROS production and groundwater chemistry was further explored by multiple linear regression, which deduced the quantitative models for estimating ROS production upon oxygenation of groundwater from different sources with different chemistry. Using the abstracted groundwater in western Bengal basin as an example, the estimated results indicated that ROS production had a great potential to oxidize the typical contaminant of As(III). As ROS, particularly •OH, represents strong oxidants, our findings implicate an overlooked oxidative capacity during groundwater abstraction and discharging in hyporheic zones or other areas, which could lead to the oxidative transformation of substances and the oxidative stress of microbial metabolism and associated biogeochemical processes in the environments suffering from groundwater oxygenation. This oxidative capacity is particularly important when the groundwater with low Eh values, i.e., under strongly reductive conditions, were abstracted and oxygenated in the surface.
研究领域:
环境科学
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地球化学
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水文地质学
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水资源管理
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产品关联
DOI
高影响因子
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