Valorization and characterization of bio-oil from Salvadora persica seed for air pollutant adsorption

Salvadora persica (SP) is an important medicinal plant. Numerous articles have been conducted on the leaf, the roots, and the stem of the plant, but there is little information about the seed. Thus, the present work tries to identify the chemical composition of SP seed bio-oil and investigates its use as an adsorbent for cyclohexane removal. This study extracted bio-oil from seeds using different polar and non-polar organic solvents. Two techniques have been used to determine the chemical composition of the bio-oil extracted: FTIR and GC-MS. Results show that the extracted bio-oil presented 13 new major organic bio-compounds in n-hexane and ethanol SP seed extracts. Moreover, the analytical results showed that the two extracts are complex and contained thiocyanic acid, benzene, 3-pyridine carboxaldehyde, benzyl nitrile, ethyl tridecanoate, ethyl oleate, and dodecanoic acid ethyl ester. Additionally, each technique of analysis showed that the extracted bio-oils from SP seeds are rich in non-polar compounds. Indeed, the major fatty acids obtained are pentadecylic acid, myristic acid, lauric acid, oleic acid, margaric acid, and tricosanoic acid. This work provides guidelines for identifying these compounds, among others, and offers a platform for using SP seeds as a herbal alternative for various chemical, industrial, and medical applications. Furthermore, the capacity of SP extracts for air pollution treatment, namely, the removal of cyclohexane in batch mode, was investigated. Results showed that cyclohexane adsorption could be a chemical process involving both monolayer and multilayer adsorption mechanisms. The pores and the grooves on the surface of the SP bio-oil extract helped in adsorbing the cyclohexane with an outstanding maximum removal capacity of about 674.23 mg/g and 735.75 mg/g, respectively, for the ethanol and hexane SP extracts, which is superior to many other recent adsorbents.