Use of alginate-chitosan/MWCNTS as a novel support for Ag2O immobilization in catalytic reduction of 4-NP

Abstract

This study contributes to the preliminary development of the industrial process in water purification, by introducing novel catalysts having immobilized silver oxide particles. For such a catalytic study, 4-NP was selected as a model sample. Synthesized catalysts Algi+Chito/multi-walled carbon nanotubes (MWCNTs), Ag2O having SDS (Cs90 (Ag2O)), Algi+Chito/MWCNTs, Ag2O having CTAB (Cc90 (Ag2O)), and Algi+Chito/MWCNTs, Ag2O having DMF (CD90 (Ag2O)) were comparatively characterized with respect to supporting matrices (Cs90, Cc90, and CD90 nanocomposites without silver oxide particles) by Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Brunauer–Emmett–Teller, and mechanical testing. The catalysts have dispersed silver oxide particles, showed prominent peaks of participating components (Ag–O, COOH-MWCNTs, alginate, and chitosan), are more porous (surface area of (Cs90 (Ag2O)), Cc90 (Ag2O), CD90 (Ag2O) is 8.671, 8.902, and 7.893 m2/g, respectively), compact (swelling is 9.9, 9.1, and 7.2 g/g for Cs90 (Ag2O), Cc90 (Ag2O), CD90 (Ag2O) catalyst), and mechanical strong (Youngs Modulus is 265.78 N/mm) than the supporting matrices. 4-NP was successfully catalyzed by synthesized catalysts in 20–60 min and followed the first-order kinetics in which the rate of reaction is accelerated by the amount of catalyst. Catalytically active nanocomposites could be reused at least five times with no mechanical loss, opening the possibility of recycling environmentally friendly catalysts in a continuous flow system. Surfactant-containing catalysts are more porous and liable for rapid catalytic reaction than non-surfactant-containing catalysts.