![]() Therefore, the preparation of high-efficiency functional composites is a novel approach to solving the above problems.īiochar (BC) can be used as a mechanical supporter to enhance the stabilization and dispersivity of nanoparticles due to its large surface area, high stability, and rich porous structure, thus improving the nZVI reactivity. Although these carbon sources have good carbon supply efficiency, they still have some limitations, such as fast carbon release rate, insufficient dose or overdosing risk, and rather sophisticated and costly control process. For example, methanol, ethanol, acetic acid, and glucose are often injected into organic carbon-limited groundwater. At present, liquid organic substances are used extensively. It can be used as an electron donor and energy source to improve the biological reductive dechlorination efficiency by promoting the growth of organohalide-respiring or extracellular-respiring bacteria. Moreover, organic carbon source has been considered as a most promising biological reductant for 1,1,1-TCA dechlorination. However, nZVI particles in an aqueous environment can easily agglomerate due to the electrostatic interaction, thus decreasing its reaction rate and migration distance in the subsurface. The major reduction mechanisms of nZVI include direct electron transfer from iron to chlorinated solvents, reduction with ferrous iron, and electrocatalytic reduction with hydrogen. Nanoscale zero-valent iron (nZVI) is the most commonly used chemical reductant for 1,1,1-TCA dechlorination due to its large specific surface area, high reaction activity, and less secondary pollution. The remedial material is a key factor that influences the treatment effect of this technology. ![]() Therefore, in situ enhanced reductive dechlorination (ERD) has become a widely used technology for the remediation of groundwater contaminated by 1,1,1-TCA, which achieves desirable performance by facilitating both chemical and biological dechlorination pathways. ![]() The relative anaerobic environment in groundwater is conducive to the dechlorination degradation of organochloride solvents. In conclusion, the composite coupling with CN32 can be a potential technique to apply for 1,1,1-TCA removal in groundwater. The results were as follows: (1) The composite surface was rough and porous, and PCL and nZVI were loaded uniformly onto the biochar surface as micro-particles and nanoparticles, respectively (2) the optimal mass ratio of PCL, biochar, and nZVI was 1:7:2, and the optimal composite dosage was 1.0% (w/v) (3) under the optimal conditions, + CN32 exhibited excellent removal performance for 1,1,1-TCA, with a removal rate of 82.98% within 360 h, while the maximum removal rate was only 41.44% in the nZVI + CN32 treatment (4) the abundance of CN32 and the concentration of adsorbed Fe(II) in the + CN32 treatment were significantly higher than that in control treatments, while the total organic carbon (TOC) concentration first increased and then decreased during the culture process (5) the major improvement mechanisms include the nZVI-mediated chemical reductive dechlorination and the CN32-mediated microbial dissimilatory iron reduction. The synergy effect and improvement mechanism of 1,1,1-TCA removal from simulated groundwater in the presence of coupling with Shewanella putrefaciens CN32 were investigated. In this study, a novel composite with nanoscale zero-valent iron (nZVI) supported by polycaprolac-tone (PCL)-modified biochar ( ) was synthesized via solution intercalation and liquid-phase reduction to address the 1,1,1-TCA pollution problem in groundwater. 1,1,1-Trichloroethane (1,1,1-TCA) is a typical organochloride solvent in groundwater that poses threats to human health and the environment due to its carcinogenesis and bioaccumulation.
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