Nano-sized and microporous palladium catalyst supported on modified chitosan/cigarette butt composite for treatment of environmental contaminants

Abstract

This study reports a versatile process for the fabrication of a microporous heterogeneous palladium nanocatalyst on a novel spherical, biodegradable, and chemically/physically resistant catalyst support consisting of chitosan (CS) and cigarette waste-derived activated carbon (CAC). The physicochemical properties of the microporous PdCS-CAC nanocatalyst developed were successfully determined by FTIR, XRD, FE-SEM, TEM, BET, and EDS techniques. TEM studies showed that the average particle size of the synthesized Pd NPs was about 30 nm. The catalytic prowess of microporous Pd-CS-CAC was evaluated in the reduction/decolorization of various nitroarenes (2-nitroaniline (2-NA), 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), and 4-nitro-o-phenylenediamine (4- NPD)) and organic dyes (methyl red (MR), methyl orange (MO), methylene blue (MB), congo red (CR), and rhodamine B (RhB)) in an aqueous medium in the presence of NaBH4 as the reducing agent at room temperature. The catalytic activities were studied by UV–Vis absorption spectroscopy of the supernatant at regular time intervals. The short reaction times, mild reaction conditions, high efficiency (100% conversion), easy separation, and excellent chemical stability of the catalyst due to its heterogeneity and reusability are the advantages of this method. The results of the tests showed that reduction/decolorization reactions were successfully carried out within 10–140 s due to the good catalytic ability of Pd-CS-CAC. Moreover, Pd-CS-CAC was reused for 5 consecutive times with no loss of the initial shape, size, and morphology, confirming that it was a sustainable and robust nanocatalyst.