Advances in low-temperature extraction of natural resources using liquefied dimethyl ether

This review summarized the valuable works on the extraction technologies using pure liquefied dimethyl ether(DME)as the organic solvent.DME is a colorless gas with a slight ether-like fragrance at room temperature and pressure.Due to some special properties,such as the strong ability for extracting organic compounds and water,high extraction rate,cheap price,low extraction temperature,and energy consumption,environmental friend-liness,safety,and good compressibility,the application of liquefied DME to the extraction process shows many advantages and has strong potential market competitiveness.On the other hand,the drawbacks of liquefied DME extraction technology were also revealed,mainly on fire hazards,solvent loss,and lack of large-scale application.Furthermore,the previous studies on the application of liquefied DME extraction technology were divided into three parts based on the extracts(water,lipid/oil,and specific ingredients)and listed one by one.The research of the liquefied DME extraction process is still in development.In the future,it is expected that this technology can be continuously improved and optimized in both lab and industrial scales,together with the extension of its application range to more various natural resources.

Production of solid fuels by hydrothermal treatment of wastes of biomass,plastic,and biomass/plastic mixtures:A review

Traditional disposal methods of biomass and plastic waste,such as landfill,combustion,and compost,no longer meet the requirements of carbon reduction,carbon neutrality,and sustain-able society due to low utilization efficiency and severe pollution.As a green,efficient and environmentally-friendly method,hydrothermal technology has been paid much attention to and has already been applied to recycle or reuse various plastic and biomass wastes.No matter for the single or mixed type of waste,it is expected to achieve efficient recycling and obtain value-added products through the hydrothermal process.This review summarized the basic knowledge of hydrothermal technology and the possible reaction mechanism of biomass and plastics un-der hydrothermal conditions and listed the previous reports on the application of hydrothermal technology for converting wastes of biomass,plastic,and biomass/plastic mixtures to solid fuels.Moreover,regarding the future of hydrothermal technology,four points related to reaction mech-anism,synergistic effect,catalysis,and scaled-up application,were provided for consideration.