Relative efficiency comparison of carboxymethyl cellucose (CMC) stabilized Fe-0 and Fe-0/Ag nanoparticles for rapid degradation of chlorpyrifos in aqueous solutions

Abstract

This study investigated the rate of chlorpyrifos degradation with different carboxymethyl cellulose (CMC) stabilized and unstabilized iron-based nanoparticles viz. CMC-Fe-0, CMC-Fe-0/Ag and Fe-0 under different concentrations of chlorpyrifos. FT-IR and SEM analysis indicated that CMC molecules were adsorbed to nanoparticles through the carboxylate (COO-) and hydroxyl (OH-) groups. All CMC stabilized nanoparticles exhibited excellent stability against aggregation because of both electrostatic and steric repulsions. The capability of CMC stabilized nanoparticles for the degradation of chlorpyrifos was investigated, which showed the maximum degradation with CMC-Fe-0/Ag and the least with Fe-0 nanoparticles when treated for about 4.0 hrs. The calculated first order rate constants (k(obs)) were 0.377 hr(-1), 0.555 hr(-1) and 0.749 hr(-1) for Fe-0, CMC-Fe-0 and CMC-Fe-0/Ag nanoparticles respectively. The rate of degradation increased as a function of Ag concentration in CMC-Fe-0/Ag nanoparticles. Temperature was also played an important role on the chlorpyrifos degradation, in which the rate constant of CMC-Fe-0/Ag nanoparticles declined from 0.910 hr(-1) to 0.690 hr(-1) when the temperature was altered from 35 degrees C to 25 degrees C. The stability experiments revealed that the CMC-Fe-0/Ag nanoparticles were stable and they were capable for the degradation of chlorpyrifos even after 3 months of their preparation.