Valorization of cotton residues for production of bio-oil and engineered biochar

Cotton seed was submitted to fast pyrolysis in a fixed bed reactor and the liquid and solid products were characterized applying several techniques. The detailed chemical composition of the bio-oil was investigated using GC x GC/TOFMS combined with software tools and retention index. A total of 257 compounds were tentatively identified with 168 were confirmed by LTPRI. The most abundant compounds identified in the cotton seed bio-oil were nitrogenous (56 compounds) and phenolic (42 compounds) what distinguishes this bio oil from others, produced from various sources of biomass. The higher heating values of cotton seed and bio-oil were 19.34 MJ kg(-1) and 34.25 MJ kg(-1) respectively and demonstrating the feasibility of the use of cotton seed in its natural form for energy generation or as a secondary source once a bio-oil with these characteristics would be a suitable candidate for use in boilers for heating purposes or chemical extraction. The biochar had a significant carbon content and a high heating value (22.12 MJ kg(-1)), making it attractive for fuel applications. The activation methods used were able to improve the physical and chemical characteristics of the biochar, as demonstrated by methylene blue adsorption tests. The maximum adsorption capacity of NaOH-activated biochar was 23.82 mg g(-1) while that of K2CO3-activated biochar was 332.40 mg g(-1). (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

Cotton seed was subjected to fast pyrolysis to obtain bio-oil and biochar, which were characterized for their detailed chemical composition and combustion properties. The study revealed that the main compounds in the bio-oil were nitrogenous and phenolic compounds, while the biochar showed good adsorption performance and high heating value.