PLA/CS-ZnO bionanocomposite for rapid catalytic reduction of nitrophenol compounds as a heterogeneous nanocatalyst.

ABSTRACT

In this research, a high efficiency and environmentally friendly method to reduce nitrophenol compounds such as 4-nitrophenol (4-NP), 2,4,6-trinitrophenol (2,4,6-TNP) and 2,4-dinitrophenol (2,4-DNP) was used in the presence of poly(lactic acid)/chitosan-ZnO ( PLA/CS-ZnO) bionanocomposite. Using FT-IR, SEM, XRD and UV-Vis techniques, PLA/CS-ZnO bionanocomposite was identified after synthesis. Also, the mechanical properties of the bionanocomposite were investigated using the stress-strain curve. The mentioned bionanocomposite showed a very good efficiency in reducing nitrophenol compounds to aminophenolic compounds, so that under optimal conditions, 100% conversion and selectivity in the reduction of 4-NP, 2,4,6-TNP and 2,4-DNP to 4-aminophenol (4-AP), 2,4,6-triaminophenol (2,4,6-TAP) and 2,4-diaminophenol (2,4-DAP) were observed. UV-Vis absorption spectrum at different times were used to evaluate the progress of the reaction. Furthermore, after the reaction, PLA/CS-ZnO was recovered and used for the next cycle. The results showed that the bionanocomposite can perform ten consecutive cycles without a significant decrease in efficiency. The comparison of catalytic activity with other catalysts showed that the bionanocomposite synthesized in the present research has a higher efficiency in reduction of nitrophenol compounds.