The pyrolysis of six biomass samples consists of Rice husk (RH), Coconut shell (CS), and Walnut shell (WS) as lignocellulosic biomasses and Cladophora glomerata (CG), Gracilaria gracilis (GG), and Azolla filiculoides (AF) as algal biomasses were investigated at a constant operating condition in a fixed-bed reactor. The effect of biomass biochemical structure on the yields and composition of pyrolysis products and their potential for future applications were discussed. CS, AF, and CG showed respectively the highest yield of bio-oil (50.25 wt%), biogas (33.70 wt%), and biochar (40.21 wt%). WS, AF, and RHderived gas products had a medium level of LHV (10-13 MJ/Nm 3 ), and CG and GG algae samples had a very suitable H 2 /CO ratio close tow. Characterization of bio-oils showed that CS, WS had a high content of hydrocarbon components (23.5%, 17.6%, and 17%, respectively), and phenols (35.3% and 35.6%, respectively). Furthermore, useful nitrogen-containing components such as pyridine, nitrile, indole, and derivatives were detected in algae bio-oils. Biochar characterization showed the highest surface area and total pore volume for AF. Also, CG's biochar with a high concentration of carboxylic and carbonyl groups in their structure may be suitable for absorbing water and soil contaminants.

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.