A combination of bentonite-supported bimetallic Fe/Pd nanoparticles and biodegradation for the remediation of p-chlorophenol in wastewater

While it is possible to dechlorinate p-chlorophenol (p-CP) into phenol using iron-based nanoparticles, phenol is still a toxic contaminant. This study examines the complete degradation of p-CP using a combination of dechlorinating p-CP with bentonite-supported Fe/Pd nanoparticles (B/Fe/Pd), and the subsequent oxidation of phenol into non-toxic compounds via the Bacillus fusiformis (BFN) strain. Batch experiments showed that 98.7% of p-CP was dechlorinated and 92.3% of phenol was formed using 5 g/L of B/Fe/Pd in 120 min. With regard to biodegradation, the Bacillus fusiformis (BFN) strain grew well in the presence of B/Fe/Pd up to 2 g/L in medium. A high concentration of B/Fe/Pd added to the cell resulted in inhibited cell growth and SEM indicated that Fe/Pd nanoparticles adhered to cell membranes. However, 94.7% of phenol was removed using BFN in 12 h at pH 6.7, 30 °C, and 0.2% of inoculum concentration in the presence of 2 g/L B/Fe/Pd. Furthermore, biodegradation kinetics fitted well to the pseudo first-order model. Finally, the method proposed here demonstrated the possibility of removing p-CP from wastewaters.