Study on free and entangled binary metal nanocatalysts for removal of 2,4,6-trichlorophenol in aqueous phase: a comparative study

Abstract

The present study highlights the comparative catalytic removal of 2,4,6-trichlorophenol (TCP) in aqueous phase by binary metal nanocatalysts in free as well as entangled forms. In brief, binary nanocatalysts comprising of Fe-Ni are prepared, characterized, and subsequently entangled in reduced graphene oxide (rGO) for better performances and reuse applications. Optimization studies on the mass of free and rGO-entangled binary nanocatalysts with respect to TCP concentration and other environmental factors are studied in detail. Results suggest binary nanocatalysts in free form at 40 mg/ml took 300 min to dechlorinate 600 ppm of TCP, whereas rGO-entangled Fe-Ni catalyst took only 190 min. Experiments on the reuse of the catalyst with respect to removal efficiency implied compared to free form rGO-entangled nanocatalysts exemplify more than 98% of removal efficacy even after 5 times of exposure to 600 ppm TCP concentration. High-performance liquid chromatography analysis display a pattern of sequential dechlorination during catalytic process. Followed by dechlorination, the phenol-enriched aqueous phase exposed to Bacillus licheniformis SL10, which degrades the phenol effectively within 24 hours. In conclusion, the prepared binary metal nanocatalysts, both in free as well as in rGO-entangled forms, effectively dechlorinate 2,4,6-TCP contaminations in aqueous phase, but with significant differences in time taken for the removal. And entanglement facilitate the reuse of the catalyst more effectively. The accumulated phenol biocatalytically removed and suggests the reuse applications of treated water.