Surfactant-enhanced PEG-4000-NZVI for remediating trichloroethylene-contaminated soil. (March 2018)

• Record Type: Journal Article
• Authors: Tian, Huifang; Liang, Ying; Zhu, Tianle; Zeng, Xiaolan; Sun, Yifei
• Is Part Of: Chemosphere. Volume 195(2018)
• Page Start: 585
• Page End: 593
• Publication Date: 2018-03
• Subjects: Modified nano zero-valent iron -- Trichloroethylene -- Surfactant -- Soil remediation -- Dechlorination; Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2017.12.070
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: In this study a NZVI was prepared by the liquid phase reduction method. The modified NZVI obtained was characterized by BET, TEM and XRD. The results showed that the iron in the PEG-4000 modified material is mainly zero-valent iron with a stable crystal structure. It has a uniform particle size, ranging from 20 to 80 nm, and a larger specific surface area than CTAB modified NZVI, SDS modified NZVI and commercial zero-valent iron. The two surfactants CTAB and SDS are also selected as solubilizers, the results showed that the two selected surfactants obviously solubilize trichloroethylene in soil. Compared with commercial zero-valent iron, PEG-4000 modified NZVI is better removed trichloroethylene from soil; Also, the optimal operational parameters were obtained. When the experimental conditions were: PEG-4000 modified NZVI dosage 1.0 g/L, CTAB/SDS concentration equal to the CMC, SDS concentration was 2.0 × CMC, CTAB was concentration 1.0 × CMC and the vibration speed 150 r/min, the removal efficiency of trichloroethylene in a soil-water system reached 100% after 4 h. Both NZVI combined with CTAB and NZVI combined with SDS followed fitted first order reaction kinetics during the removal of trichloroethylene and their reaction rate constant k was 0.6869 mg/(L·h) and 0.5659 mg/(L·h), respectively. According to the chloride ion detection test, the trichloroethylene degradation is mainly due to reductive dechlorination. Highlights: A new modified PEG-4000-NZVI was prepared and used in soil remediation. Two surfactants strongly solubilized trichloroethylene. The modified PEG-4000-NZVI worked well within a pH range of 3–11. Almost all trichloroethylene was removed from soil within 3 h.