A polymeric Brønsted acid ionic liquid mediated liquefaction of municipal solid waste

Abstract

The rapid industrialization and population explosion continuously generate massive amounts of municipal waste. Several conventional processes are in practice for the treatment of municipal waste, but the requirement of stringent operating conditions, incomplete conversion, longer processing time and emission of toxic gases, etc., are the major associated barriers. Thus, there is an urgent requirement for a sustainable, environmentally feasible process that can process waste into energy and fuel products. In the present manuscript, polyethylenimine functionalized polymeric Bronsted acid ionic liquid (PolyE-IL) catalysts have been explored for the Catalytic Thermo Liquefaction (CTL) of organic biodegradable municipal solid waste (MSW). A series of PolyE-IL catalysts with variable counter ions were examined for CTL of MSW. Of all the tested PolyE-IL catalysts, the integration of [PEI]+[HSO4]- gave excellent MSW conversion (>85%) and yield (>80%) of liquefied products (CTL-Oil) under non-stringent reaction conditions and without any formation char and gases. The influence of reaction conditions such as catalyst concentration, reaction temperature, time, slurry concentration, and type of feedstock of conversion and yield are studied. The column adsorption and membrane separation process was integrated to facilitate the catalyst and CTL-Oil separation. A series of commercially available hydrophobic resins were tested to separate catalyst and CTL-Oil. ICT005 showed the highest adsorption efficiency of all tested resins with 35.46 mg/mL of binding capacity and Kd of 0.02159. The physicochemical properties of CTL-Oil were studied in detail by using various analytical tools, which exhibited that CTL-Oil comprises a mixture of small and large molecular weight organic compounds and has a calorific value of 4000 kcal/kg; hence it could be used for further energy and fuel applications. Thus, the reported CTL process can be beneficial to resolve both environmental and fossil fuel dependency issues simultaneously by converting MSW into CTL-Oil.