Production of high‐quality bio‐product by pyrolysis of acid/metal modified chickpea husk

Abstract

Summary Acid washing of the biomass and impregnating it into the catalyst are two useful techniques for promoting bio‐products generated during the pyrolysis process. This study investigated the potential of these pretreatment methods on the composition of bio‐products resulting from the pyrolysis of chickpea husk (ChH). To improve the quantity and quality of bio‐oil, the ChH was pretreated with HCl acid‐washing, and nickel (1‐10 wt%)/cerium (0.1‐0.3 wt%) impregnation. The bio‐oil yield increased by acid treatment (from 42.9 to 45.2 wt%), while impregnation with Ni and Ce had a maximum yield in a certain concentration (47.2 wt% bio‐oil in loading of 1% Ni and 0.1% Ce). Acid‐washing reduced the acidic and oxygenated compound concentrations (aldehydes, ketones, ethers, and esters) (from 27.01% to 15.27%) and also led to an increase in the efficiency of sugar compounds in bio‐oil (from 19.63% to 31.85%). Impregnation of acid‐washed ChH (AChH) with Ni and Ce increased the calorific value of bio‐oil with high amounts of furfural, D‐allose, LAC, levoglucosan (LG), and toluene and yielded a high amount of hydrogen. The raw and modified biomass characteristics were determined utilizing CHNS, TGA‐DTG, XRF, and FESEM‐EDS techniques. The bio‐products were investigated by GC‐TCD, CHNS, GC‐MS, and ICP‐OES analyzers. This study's findings help convert agricultural waste, such as ChHs that are generally burned by processing industries, which leads to pollution of the environment and wasting the contained energy in them, into valuable bio‐products with various applications.