Decoloration of acid violet red B by bentonite-supported nanoscale zero-valent iron: Reactivity, characterization, kinetics and reaction pathway

Abstract In this study, bentonite (Bent)-supported nanoscale zero-valent iron (Fe 0 ) (Fe 0 Bent) was prepared to remove acid violet red B from an aqueous solution. Scanning electron microscopy (SEM) images of Fe 0 Bent and batch experiments indicated that the presence of bentonite decreased aggregation of iron nanoparticles and increased their reactivity. After reacting for 9 min, Fe 0 Bent removed 95.6% of acid violet red B with a concentration of 800 mg/l compared to Fe 0 , which removed 75.1%. Iron oxide and hydroxide were the reaction products of the reaction of Fe 0 Bent with acid violet red B. UV–vis spectra showed that the absorption peak of acid violet red B was degraded due to the break of azo linkages. Kinetic studies showed that the degradation rate suited the pseudo-first-order model well. The apparent activation energy was 40.86 kJ/mol, which is typical of a chemically controlled reaction on the smectite surface. The Fe 0 Bent used to remove acid violet red B has the potential to be used for in situ remediation.