Synthesis, Characterization, and Application of Fe–Ni Bimetallic Nanoparticles for the Reductive Degradation of Nimesulide

Abstract

Carboxymethyl cellulose (CMC) stabilized Fe‐Ni bimetallic nanoparticles (CMC‐bNP‐Fe‐Ni) were used for the reductive degradation of the drug nimesulide (NMS) in aqueous solution and in a secondary effluent. The influence of the concentrations of CMC‐bNP‐Fe‐Ni and NMS as well as the Ni content were investigated systematically. Nanoparticles containing 17 wt% of Ni showed the best performance for the reductive degradation of NMS. A complete removal of NMS was verified with the formation of aromatic by‐products for concentrations of NMS ranging from 10 to 60 mg L−1 using CMC‐bNP‐Fe(0.83)–Ni(0.17) (0.2 g L−1). As the CMC‐bNP‐Fe(0.83)–Ni(0.17) and NMS concentrations increased, so did the removal rate, a result consistent with a heterogeneous reaction carried out under agitated conditions. The degradation of NMS using the CMC‐bNP‐Fe(0.83)–Ni(0.17) system in the presence and absence of dissolved oxygen revealed that oxygen affects the process for NMS concentrations <45 mg L−1. A comparative study using CMC‐bNP‐Fe(0.83)–Ni(0.17), bNP‐Fe(0.83)–Ni(0.17), and CMC stabilized zero‐valent iron nanoparticles (CMC‐ZVIn) revealed that higher degradation levels of NMS were only obtained with the CMC‐bNP‐Fe(0.83)–Ni(0.17) system by means of the reduction of nitro and sulfonyl groups with the formation of aromatic by‐products. The reductive treatment of a secondary effluent with CMC‐bNP‐Fe(0.83)–Ni(0.17) led to a rapid decrease in the NMS concentration, with a percentage reduction of 95% achieved after 5 min of reaction.