Uncatalysed oxidative degradation of cefadroxil by heptavalent manganese during water treatment: Reaction kinetics and pathways

Abstract

The kinetic outcome shows unit order for heptavalent manganese (HVMG) and fractional orders for substrate cefadroxil (CFR) and H+ ions. Five oxidation products of CFR were identified by mass spectral analysis. The effect of different parameters on the oxidation kinetics of CFR by HVMG was studied thoroughly. Permanganic acid is found to be an active dominant and strong oxidizing species. The pH dependent second order rate constants were determined and found higher in acidic medium. Rate constants and activation parameters were evaluated from the influence of variation in temperature on the rate of reaction. The plausible mechanism and derived rate law are consistent with the experimental results. There is a formation of intermediate complex between CFR and HVMG which subsequently degrades into various degraded products.The kinetic outcome shows unit order for heptavalent manganese (HVMG) and fractional orders for substrate cefadroxil (CFR) and H+ ions. Five oxidation products of CFR were identified by mass spectral analysis. The effect of different parameters on the oxidation kinetics of CFR by HVMG was studied thoroughly. Permanganic acid is found to be an active dominant and strong oxidizing species. The pH dependent second order rate constants were determined and found higher in acidic medium. Rate constants and activation parameters were evaluated from the influence of variation in temperature on the rate of reaction. The plausible mechanism and derived rate law are consistent with the experimental results. There is a formation of intermediate complex between CFR and HVMG which subsequently degrades into various degraded products.