Building a microscale zero-valent iron (mZVI) reaction zone is a promising in situ remediation technology for restoring groundwater contaminated by trichloroethylene (TCE). In order to determine a suitable modifier that could not only overcome gravity sedimentation of mZVI but also improve its remediation efficiency for TCE, the three biopolymers xanthan gum (XG), guargum (GG), and carboxymethyl cellulose (CMC) were employed to coat mZVI for surface modification. The suspension stability of the modified mZVI and its TCE removal efficiency were systematically investigated. The result indicated that XG as a shear-thinning fluid showed the most remarkable efficiency of preventing mZVI from gravity sedimentation and enhancing the TCE removal efficiency by mZVI. In a 480-h experiment, the presence of XG (3 g L(-1)) increased the TCE removal efficiency by 31.85 %, whereas GG (3 g L(-1)) and CMC (3 g L(-1)) merely increased by 15.61 and 9.69 % respectively. The pH value, Eh value, and concentration of ferrous ion as functions of the reaction time were recorded in all the reaction systems, which indicated that XG worked best in buffering the pH value of the solution and inhibiting surface passivation of mZVI.
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http://dx.doi.org/10.1007/s11356-016-6368-z | DOI Listing |
ACS Appl Mater Interfaces
January 2025
Department of Environmental Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea.
Trichloroethylene (TCE) is widely used in various industrial applications, leading to significant environmental and public health concerns due to its toxicity and persistence. Current nonthermal liquid-phase TCE treatment methods, including electrochemical processes, typically produce liquid byproducts that require additional separation steps, limiting their efficiency. To overcome these challenges, this study introduces an innovative electrochemical approach for the direct conversion of TCE gas into less harmful gaseous products, utilizing a Cu/Ni alloy 3D foam electrode integrated with a poly(vinyl alcohol) (PVA)-sodium polyphosphate (SPP) gel membrane system.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
Department of Civil, Construction and Environmental Engineering, San Diego State University, 5500 Campanile Drive, San Diego, CA 92182, USA.
Highly toxic halo-/nitro-substituted organics, often in low concentrations and with high hydrophobicity, make it difficult to obtain electrons for reduction when strongly electron-competing substances (e.g., O, H/HO, NO) coexist.
View Article and Find Full Text PDFJ Hazard Mater
December 2024
MOE Key Lab of Environmental Remediation and Ecosystem Health, College of Environmental and Resource Science, Zhejiang University, Hangzhou, China,. Electronic address:
In situ remediation of low-permeability soils contaminated with trichloroethylene (TCE) is challenging due to limited mass transfer and low bioavailability in clay soils. The electrokinetic-enhanced bioremediation (EK-BIO) system offers a promising solution by combining electrokinetics with bioremediation to address these challenges. While previous studies have demonstrated microbial succession and TCE removal, the long-term performance of dechlorination and interactions between electrode reactions and anaerobic dechlorination remain unclear.
View Article and Find Full Text PDFEnviron Technol
November 2024
Chongqing Juchuan Environmental Engineering CO., LTD., Chongqing, People's Republic of China.
Nanotechnology
November 2024
Gleb Wataghin Institute of Physics (IFGW), University of Campinas (UNICAMP), Campinas, Brazil.
Two-dimensional (2D) materials, particularly transition metal dichalcogenides (TMDs), have gathered significant attention due to their interesting electrical and optical properties. Among TMDs, monolayers of WSeexhibit a direct band gap and high exciton binding energy, which enhances photon emission and absorption even at room temperature. This study investigates the electronic and optical properties of WSemonolayers when they are mechanically transferred to indium tin oxide (ITO) substrates.
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