| 摘要: | 摘要： •LECS was developed for continuous carbon and nanoscale zero-valent iron (nZVI) release.•LECS contained nZVI, vegetable oil, surfactants, lactate, molasses, minerals, and vitamins.•LECS created anaerobic conditions and caused TCE biodegradation and chemical reduction.•Oxidation of released nZVI from LECS produced hydroxide ion and neutral pH can be maintained.•Released nZVI could produce iron sulfide, and odor and acidification problems could be prevented. A long-lasting emulsified colloidal substrate (LECS) was developed for continuous carbon and nanoscale zero-valent iron (nZVI) release to remediate trichloroethylene (TCE)-contaminated groundwater under reductive dechlorinating conditions. The developed LECS contained nZVI, vegetable oil, surfactants (Simple Green™ and lecithin), molasses, lactate, and minerals. An emulsification study was performed to evaluate the globule droplet size and stability of LECS. The results show that a stable oil-in-water emulsion with uniformly small droplets (0.7μm) was produced, which could continuously release the primary substrates. The emulsified solution could serve as the dispensing agent, and nZVI particles (with diameter 100–200nm) were distributed in the emulsion evenly without aggregation. Microcosm results showed that the LECS caused a rapid increase in the total organic carbon concentration (up to 488mg/L), and reductive dechlorination of TCE was significantly enhanced. Up to 99% of TCE (with initial concentration of 7.4mg/L) was removed after 130 days of operation. Acidification was prevented by the production of hydroxide ion by the oxidation of nZVI. The formation of iron sulfide reduced the odor from produced hydrogen sulfide. Microbial analyses reveal that dechlorinating bacteria existed in soils, which might contribute to TCE dechlorination.
其他題名： J Hazard Mater
出版者： Netherlands: Elsevier B.V
出版日期： 2015-03-02
出處： Journal of hazardous materials, 2015-03, Vol.284, p.222-232
版權： 2014 Elsevier B.V.
版權： Copyright © 2014 Elsevier B.V. All rights reserved.
識別號： ISSN: 0304-3894
識別號： ISSN: 1873-3336
識別號： EISSN: 1873-3336
識別號： DOI: 10.1016/j.jhazmat.2014.11.023
識別號： PMID: 25463237 |
