Rapid removal of 2,4-DCP by activated carbon loaded nano-zero valence iron immobilized microorganisms

Abstract

PEG-nZVI/GAC@B was used to repair 2,4-DCP contamination which was difficult to solve by traditional physical, chemical and biological methods. Characterization techniques confirm the successful incorporation of nZVI particles and Bacillus marisflavi into the GAC's surface folds and pores. The polyethylene glycol 4000 (PEG-4000) coating prevents the formation of Fe³⁺ on nZVI surfaces. Compared to standard GAC, PEG-nZVI/GAC@B demonstrates higher electron transfer efficiency. Key parameters including nZVI content, PEG/nZVI mass ratio, and immobilization time were optimized for maximum efficiency. PEG-nZVI/GAC@B also shows effectiveness in removing other chlorophenol compounds. The removal process primarily involves GAC adsorption, followed by Bacillus marisflavi degradation and nZVI-induced reductive dechlorination. Analyses using IC and GC-MS reveal rapid dechlorination of 2,4-DCP adsorbed on immobilized microorganism by nZVI, with Bacillus marisflavi facilitating further mineralization of the system by degrading 2,4-DCP and its dechlorination products. Most intermediate degradation products exhibit lower ecological toxicity than 2,4-DCP, highlighting immobilized microorganism as a promising solution for 2,4-DCP pollution.