Removal of methyl orange from aqueous solution using SRB supported Bio-Pd/Fe NPs

Abstract Removal efficacy of biogenically (Desulfovibrio desulfuricans) synthesized bimetallic Pd/Fe nanoparticles on the toxic azo dye Methyl Orange (MO) was evaluated using DM and natural water bodies. Nanoparticle concentration and conditions were optimized using response surface methodology (RSM). Biogenic Pd/Fe nanoparticles exhibited higher removal (96.16 ± 1.6%) efficiency in just 30 min. The role played by D. desulfuricans and Pd catalyst in MO removal was also assessed and 36.8 ± 1.4% removal by D. desulfuricans and 45.19 ± 1.7% by the Bio-Pd NPs were noted. Mechanism of removal of MO by Bio-Pd/Fe NPs as revealed by XRD, FTIR and ORP analyses showed both adsorption and reduction processes. Removal studies carried out with the lake, tap and ground water samples showed efficiency of 74 ± 1.95%, 81 ± 2.57% and 87 ± 1.36% respectively. Bio-Pd/Fe nanoparticle treated MO exhibited reduced toxicity towards algal and bacterial species. Biogenic synthesis of Pd/Fe NP offers a promising approach for removal of toxic methyl orange dye from contaminated aquatic ecosystems and a methodology for remediation of MO is elucidated.