Synthesis and utilization of meso and microporous catalysts for the valorization of newspaper waste to bio-based chemicals using Choline chloride as biodegradable solvent

Abstract

The present study develops an effective and sustainable catalytic system using mesoporous (KIT-6 and NbKIT-6) and microporous catalysts (ZIF-8) for the conversion of newspaper waste to value-added products such as TRS (Total reducing sugars) and 5-HMF (5-Hydroxymethyl furfural). The bio-based products were produced using green and biodegradable solvent Choline chloride in presence of sustainable catalysts under mild operating conditions at 1 atm pressure. The study demonstrated the potential of monophasic (Choline chloride and Catalyst) and biphasic (Choline chloride, Catalyst and Extracting solvent) system and revealed their comparative insights. It was observed that both the systems were highly effective but the purity and stability of products were higher in the biphasic system compared to the monophasic system. The synthesised catalysts possess high surface area 588.528, 534.414 and 351.85 m²/g with pore volume 0.7587, 0.3574 and 0.2362 cc/g for KIT-6, NbKIT-6 and ZIF respectively. The selected extracting solvents were found to be promising and the maximum 5-HMF yield was found to be 62.12%, 73.45% and 79.66% in DMSO medium using KIT-6 (160 °C, 135 min), NbKIT-6 (140 °C, 90 min) and ZIF-8 (140 °C, 105 min) catalysts respectively. Also, all the catalysts are reusable for up to five runs with minimal loss in catalyst activity. The proposed catalytic system will help to resolve the challenges associated with biorefineries in terms of product separation and recyclability of catalysts.