One-step catalytic pyrolysis of pre-treated rice straw to biofuel over waste-extracted Ni–H3PW12O40 activated nano-catalyst

Abstract

ABSTRACT Alternative, renewable and carbon-neutral fuels are an urgent requirement. Pyrolysis has received the most attention in the conversion of biomass into fuel. The main disadvantages of chemical and physical properties of pyrolysis crude bio-oil include its high oxygen content and acidity. Catalytic fast pyrolysis can overcome this problem. Rice straw is an abundant biomass residual that can be of environmental negative impact and is not of proper use. Therefore, this research work introduces the use of this residual in the production of fuel sources by one-step catalytic pyrolysis with the reusability of the employed catalyst. A waste extraction catalyst modified with acidic and nickel sites has been prepared and was utilised for the proposed target in this study. The removal of silica, lignin and minerals by treatment of the rice straw with KOH and then HNO3 in a green terminated process improved the catalytic biomass conversion from 83% to 96% at a catalyst dose of 5%, at 250°C. The pre-treatment of the rice straw enables the reusability of the catalyst in direct catalytic pyrolysis where the employed catalyst exhibits good stability in four consecutive runs. The used KOH and HNO3 were neutralised by mixing to produce KNO3 as a valuable fertiliser.