Microalgae are potential biomass source for biodiesel production. However, their strong cell walls make efficient lipid extraction problematic. Disrupting the cell wall is a key point in enhancing lipid yield from microalgae biomass. A new type of ionic liquid (IL) has been suggested in this work as a potentially viable solvent to permeabilize the strong microalgae cell structure for the efficient extraction of lipids. Morphological changes in microalgae cells were studied before and after ionic liquid permeabilization to understand the mechanism of ionic liquid treatment. Among the three selected CO 2 -based alkyl carbamate ionic liquids, DIMCARP performed with the best extraction efficiency. The effects of extraction variables (temperature, time, ratio ionic liquid/Methanol, and solvent to biomass) on lipid extraction were examined via single-factor experiments coupled with response surface methodology (RSM) using a Box-Behnken design (BBD). The highest lipid yield (16.40%) was obtained after 45 min of extraction at 45 °C using a 9:1 ionic liquid to methanol and 7 mL of solvent to biomass ratio. Transesterification of lipids to make fatty acid methyl esters found that the most common fatty acids were C16:0, C18:2, and C18:3 (19.50%). The quality of the biodiesel made meets European and US standards.
Camellia oleifera Abel. is an important woody oilseed tree to help increase the self-sufficiency rate. In this study, lipid extraction focuses more on the solvent extraction of Camellia seed oil (CO) cakes rather than conventional cold pressing, where the performance of candidate alternative green solvents selected from hurdle technology was first evaluated. Compared to n-hexane (89.50 ± 0.00 %) and subcritical n-butane (83.75 ± 0.43 %), 2-methyloxolane (2-MeOx) performed the best with the comprehensive consideration of extraction ratio (94.79 ± 0.00 %), lipid composition and environmental impact (0.38 ± 0.07 kg of CO 2 emission). Intriguingly, 2-MeOx exhibited the highest diffusion rate at both 25 °C and 55 °C in the extraction kinetic study, which could also extract the highest total phenolic contents (351.6 ± 0.02 mg GAE/kg dw) corresponding to its best oxidative stability. Besides, Hansen solubility modeling could help better understand the dissolving mechanism. 2-MeOx was demonstrated as the optimal alternative bio-based solvent to n-hexane with comparable extractability and selectivity in the CO extraction.
Jipeng Sun,Wei Zhu,Jun Cao,Jun Zhong,Biao Mu,Xin Wang,Naixi Lin
In the context of low-carbon development, it is important to promote resource utilization of kitchen waste, which has the dual properties of pollution and resources. In this study, we explored a method to enhance biochar yield and tetracycline adsorption performance using subcritical dimethyl ether (DME) dewatering and lipid-extraction pretreatment . The mechanism of the effect of lipids and moisture on pyrolysis was investigated by comparing the differences among solid residue biochar, kitchen waste biochar, and dry kitchen waste biochar. Meanwhile, the adsorption performance and mechanism of solid residue biochar on tetracycline was clarified. It was found that lipids did not participate in the generation of biochar, but their decomposition products adhered to the biochar surface. Through DME pretreatment, 95.12% of lipids and 61.34% of moisture could be removed from kitchen waste, the biochar yield was increased by at least 22.77%, and the specific surface area and pore capacity were enhanced. The adsorption performance of tetracycline on solid residue biochar reached 79.11 mg•g −1 , and the potential adsorption mechanisms included π-π interaction, hydrogen bonding and pore filling.
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