Publications by authors named "Weizhao Yin"

Faced with worldwide mercury (Hg) contamination in groundwater, efficient in situ remediation technologies are urgently needed. Carboxymethyl cellulose (CMC) stabilized iron sulfide (CMC-FeS) nanoparticles have been found effective for immobilizing mercury in water and soil. Yet, the potential use of the nanoparticles for creating an in situ reactive zone (ISRZ) in porous geo-media has not been explored.

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Zero-valent iron (ZVI), as an effective medium, is widely used to eliminate heavy metal ions in filter tanks. However, it will react with Cr(VI) to generate Fe-Cr precipitates with low conductivity on its surface, resulting in slow iron corrosion and low Cr(VI) removal efficiency. In this study, three oxidants (KMnO, NaClO, and NaSO) were employed to promote iron corrosion in ZVI systems for enhanced Cr(VI) removal at a concentration of 5 mg/L through batch tests and column experiments.

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Article Synopsis
  • A weak electric field (WEF) was used to enhance the cycling of iron (Fe) within goethite-impregnated activated carbon, improving the removal of harmful chromium (Cr(VI)) from water.
  • The study found that the addition of AC helped in transferring electrons, promoting the conversion of Fe(III) to Fe(II), which effectively reduced Cr(VI) to less harmful Cr(III).
  • The WEF-enhanced system showed significantly better Cr(VI) elimination capacity and longer operational lifespan compared to traditional methods, making it a promising approach for water treatment.
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Zero-valent iron (Fe) is restricted in phosphate removal due to the formation of a passive P-Fe layer on its surface. A micro-electric field (0.20 mA cm) was employed in Fe column to facilitate iron corrosion for enhanced phosphate removal with a Fe column as the control.

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Tetrasphaera-enhanced biological phosphorus removal (T-EBPR) was developed by augmenting conventional EBPR (C-EBPR) with Tetrasphaera to improve phosphorus removal from anaerobic digestate of swine wastewater. At influent total phosphorus (TP) concentrations of 45-55 mg/L, T-EBPR achieved effluent TP concentration of 4.17 ± 1.

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In this work, zero-valent iron (ZVI) combined with anaerobic bacteria was used in the remediation of Cd(II)-polluted soil under the mediation of sulfate (SO). Owing to hydrogen-autotrophic sulfate reduction, serious corrosion occurred on sulfate-mediated biotic ZVI in terms of solid phase characterization as massive corrosive products (e.g.

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In this study, an integrated system of Fe and hydrogenotrophic microbes mediated by nitrate (nitrate-mediated bio-Fe, NMB-Fe) was established to remediate Cd(II)-contaminated sediment. Solid phase characterization confirmed that aqueous Cd(II) (Cd(II)) was successfully immobilized and enriched on iron surface due to promoted iron corrosion driven by hydrogenotrophic denitrification and subsequent greater biomineral production such as magnetite, lepidocrocite and green rust. Compared to a Cd(II) removal of 21.

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In this study, oxidants including hydrogen peroxide (HO), hypochlorite (ClO) and persulfate (SO ) were employed to promote zero-valent iron (ZVI) corrosion and enhance phosphate (P) removal from water through batch and breakthrough experiments. Characterization results indicated that the addition of oxidant can cause large-scale corrosion of the iron surface. This subsequently generates more iron ions and active minerals, resulting in a large number of reaction-adsorption sites for P removal.

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In this study, nano-sized silver oxides were loaded on activated carbon (nAgO/AC) through a facile impregnation-calcination method for enhanced bacterial inactivation from drinking water, in which Escherichia coli (E. coli) was used as target bacteria. XRD and SEM characterization confirmed that nano-sized AgO particles (50-200 nm) were successfully prepared and uniformly distributed on the surfaces and pores of AC.

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In this study, hydrogen-autotrophic microorganisms and zero-valent iron (Fe) were filled into columns to investigate hydrogenotrophic denitrification effect on cadmium (Cd(II)) removal and column life-span with sand, microorganisms, Fe and bio-Fe columns as controls. In terms of the experiment results, the nitrate-mediated bio-Fe column showed a slow Cd(II) migration rate of 0.04 cm/PV, while the values in the bio-Fe and Fe columns were 0.

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A biotic iron (Fe) treatment system combined with mixed microorganisms was applied to remediate cadmium (Cd)-contaminated groundwater under the intervention of sulfate. Due to hydrogenotrophic desulfuration effect, severe iron corrosion was observed in this microbe-collaborative Fe system according to surface morphology analysis as lots of secondary minerals (e.g.

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In this study, a collaborative system of Fe and mixed anaerobic microorganisms was established for remediating chromium (Cr)-contaminated soil and restraining the translocation of Cr from soil to swamp cabbage (Ipomoea aquatica Forssk.). Solid phase characterization demonstrated that more reactive secondary minerals such as green rust, magnetite, and lepidocrocite were generated in the composite system as compared with the Fe -only system.

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Electrochemical dechlorination is a prospective strategy to remediate trichloroethylene (TCE)-contaminated groundwater. In this work, iron-nitrogen-doped carbon (FeNC) mimicking microbiological dechlorination coenzymes was developed for TCE removal under environmentally related conditions. The biomimetic FeNC-900, FeNC-1000, and FeNC-1100 materials were synthesized via pyrolysis at different temperatures (900, 1000, and 1100 °C).

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Bone char catalyzed dechlorination of trichloroethylene (TCE) by green rust (iron(II)-iron(III) hydroxide, GR) has introduced a promising new reaction platform for degradation of chlorinated solvents. This study aimed to reveal whether a broader class of biochars are catalytically active for the dechlorination reaction and to identify which biochar properties are the most important for the catalytic activity. Biochars produced by pyrolysis of animal, plant, and sewage waste substrates at 950 °C were prepared for catalytic dechlorination of TCE by GR tested in batch experiments with 0.

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A novel macroporous strong acidic cation exchange resin (D001) modified by nano-sized goethite (nFeOOH@D001) was fabricated by using a facile ethanol dispersion and impregnation method, and its efficiency for Cr(VI) removal was tested thereafter. Due to the dispersing effect of ethanol, FeOOH particles of 20-150 nm were coated on the D001 surfaces. The nFeOOH@D001 obtained a Cr(VI) removal efficiency and capacity of 80.

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In this study, nano α-FeOOH (nFeOOH, 100-500 nm) was coated onto activated carbon (nFeOOH@AC) through a dipping means for enhanced Cr(VI) immobilization from drinking water. The nFeOOH@AC significantly improved the Cr(VI) removal from 19.9% (AC control) to 93.

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Continuous-flow iron and bio-iron columns were used to evaluate the effects of seepage velocity and concentration on Cr(VI) removal from groundwater. Solid-phase analysis showed that microorganisms accelerated iron corrosion by excreting extracellular polymeric substances and generated highly reactive minerals containing Fe(II), which gave the bio-iron column a longer life span and enhanced capacity for Cr(VI) removal via enhanced adsorption and reduction by reactive minerals. The bio-iron column showed much higher Cr(VI) removal capacity than the iron column with increasing Cr(VI) loading, which was obtained by increasing the seepage velocity or influent Cr(VI) concentration from 95 to 1138 m yr and from 5 to 40 mg L , respectively.

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Green rusts (GRs) are redox active towards contaminants but they are not stable for long distance transport during the soil and groundwater remediation. In this study, green rust chloride (GR) was stabilized by selected regents, including silicate (Si), phosphate (P), fulvic acid (FA), carboxymethyl cellulose (CMC) and bone char (BC), then these stabilized GR, collectively named GR-X, would be further applied for Cr(VI) removal from aqueous solution. The stabilization experiment demonstrated that the release of Fe(II) from GR was effectively suppressed by above reagents, enabling at least 50% lower Fe(II) leaching from the stabilized GR-X than that from the pristine GR.

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In this study, carboxymethyl cellulose (CMC) was employed to stabilize zero-valent iron nanoparticles (CMC-nFe) to improve their dispersity and antioxidation for enhanced hexavalent chromium (Cr(VI)) removal. Scanning electron microscope (SEM) observation revealed that the nFe agglomerated in clusters, while the CMC-nFe connected as chains and presented higher dispersity. Therefore, compared with 54% of the nFe, the Cr(VI) removal rate of the CMC-nFe increased by 0.

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In this study, nitrate mediated biotic zero-valent iron (Fe) corrosion was employed to enhance cadmium (Cd) removal from groundwater. In comparison with a 17.5% Cd(II) removal treated with abiotic Fe, a 3.

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Article Synopsis
  • Biochars act as mediators for electron transfer, enhancing the reduction of environmental pollutants, particularly trichloroethylene (TCE), in this study.
  • The research demonstrated that biochars produced at higher pyrolysis temperatures (PT), especially 950 °C, significantly increased TCE reduction rates, while those at lower PTs showed little to no activity.
  • Key factors affecting TCE reduction included the electron-accepting capacity (EAC), carbon content, and structure of the biochars, indicating the importance of their chemical properties for environmental remediation applications.
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A collaborative system of carboxymethyl cellulose stabilized nanosized zero-valent iron (CMC-nFe) and microorganisms was set up to enhance the stabilization of Cr(VI) in soil. In comparison with an aqueous-bound Cr(VI) removal of 18.9% in the nFe system, a higher Cr(VI) removal of 68.

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Activated carbon-coated α-FeO nanoparticles (nFeO@AC) were synthesized by a facile impregnation method to enhance hexavalent chromium (Cr(VI)) removal from water. The SEM images confirmed that α-FeO particles ranging from 90 to 500 nm were dispersedly loaded on the AC, which successfully amended Cr(VI) removal. The nFeO@AC was able to remove Cr(VI) with a 3 times higher efficiency of 94% in comparison with the AC.

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In this study, activated carbon (AC) was modified with micro-sized geothite (mFeOOH) using a facile and cost-effective impregnation method for enhanced Cr(VI) removal from aqueous solutions. X-ray diffraction (XRD) and scanning electron microscope (SEM) analysis showed that FeOOH particles with a diameter of 0.1-1 μm were dispersed homogeneously on the surfaces and pores of the AC.

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Layered Fe-Fe hydroxide chloride (chloride green rust, GR) has high reactivity toward reducible pollutants such as chlorinated solvents. However, this reactive solid is prone to dissolution, and hence loss of reactivity, during storage and handling. In this study, adsorption of silicate (Si) to GR was tested for its ability to minimize GR dissolution and to inhibit reduction of carbon tetrachloride (CT).

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