Recent progress in supercritical fluid science for biofuel production from woody biomass

Owing to an environment-friendly utilization of resources, increased attention has been focused on fuels and chemicals from biomass as an alternative to fossil resources. In addition, supercritical fluid technology has been considered to be an environmentally-benign treatment. Therefore, its technology was applied for a conversion of biomass to useful fuels and chemicals in order to mitigate environmental loading. For example, supercritical water treatment has demonstrated that lignocellulosics can be hydrolyzed to become lignin-derived products for useful aromatic chemicals and carbohydrate-derived products, such as polysaccharides, oligosaccharides and monosaccharides of glucose, mannose and xylose used for subsequent ethanol fermentation. If this treatment is prolonged, lignocellulosics were found to be converted to organic acids such as formic, acetic, glycolic and lactic acids which can be converted to methane for biofuel. When alcohols, such as methanol and ethanol, were used instead of water, some other useful products were achieved, and its liquefied products were found to have a potential for liquid biofuel. In this study, therefore, our research achievements in supercritical fluid science of woody biomass will be introduced for clean and green chemistry for a sustainable environment.

Supercritical fluid technology:A game-changer for biomacromolecular nanomedicine preparation and biomedical application

Biomacromolecules are attractive in biomedical applications as therapeutic agents and potential drug carriers due to their natural active components,good biocompatibility,and high targeting.However,their large relative molecular weight,complex structure,susceptibility to degradation,and poor stability limit their usefulness.Nanotechnology can address these issues by improving the therapeutic value,bioavailability,permeability,and absorption of biomacromolecules while regulating their retention time in the body.Especially,compelling evidence has been reported that supercritical fluid(SCF)technology has emerged as an alternative that maintains the integrity of biomacromolecules and reduces environmental contamination.In this review,we highlight a set of unique nanosizing strategies based on SCF technology for biomacromolecular nanomedicine,and extensively discuss their characteristics and mechanisms.In particular,the protein-based,nucleic acid-based,and polysaccharide-based nanomedicine preparations via SCF technology and their biomedical applications are summarized,and the potential for industrial production of biomacromolecular drugs is also considered.We further provide perspectives on the opportunities and challenges in this excellent field of biomacromolecular drugs nanotechnology.

Preparation of aripiprazole-poly(methyl vinyl ether-co-maleic anhydride)nanocomposites via supercritical antisolvent process for improved antidepression therapy

Aripiprazole(ARI),a second-generation atypical antipsychotic drug approved for schizophrenia treatment,shows good efficacy against depression.However,the poorly aqueous solubility of ARI leads to low bioavailability and increased dose-related side effects,seriously limiting its application in pharmaceutics.Herein,we demonstrated the fabrication of ARI and poly(methyl vinyl etherco-maleic anhydride)(PVMMA)composite nanoparticles(PA NPs)using the supercritical antisolvent(SAS)process for enhancing its water-solubility and curative anti-depressant effects.Initially,the optimal experimental conditions(ARI/PVMMA mass ratio of 1:6,pressure of 10MPa,and solution flow rate of 0.75ml min^(-1))were determined by a 23 factorial experimental design,resulting in the PA NPs with an excellent particle morphology.In vitro cell experiments showed that PA NPs significantly inhibited the inflammatory response caused by the microglia activation induced by lipopolysaccharide(LPS).Similarly,mice behavioral tests demonstrated that PA NPs significantly improved LPS-induced depression-like behavior.Importantly,compared with free ARI,the LPS-induced activation of microglia in the mouse brain and the expression of inflammatory factors in serum were significantly reduced after treatment with PA NPs.Together,the innovative PA NPs designed by SAS processmight provide a candidate for developing new ARI-based nano-formulations.

Recovery of rare and precious metals from urban mines —— A review

Urban mining is essential for continued natural resource extraction. The recovery of rare and precious metals （RPMs） from urban mines has attracted increasing attention from both academic and industrial sectors, because of the broad application and high price of RPMs, and their low content in natural ores. This study summarizes the distribution characteristics of various RPMs in urban mines, and the advantages and shortcomings of various technologies for RPM recovery from urban mines, including both conventional （pyrometallurgical, hydrometallurgical, and biometallurgical processing）, and emerging （electrochemical, supereritieal fluid, mechanochemical, and ionic liquids processing） technologies. Mechanical/physical technologies are commonly employed to separate RPMs from nonmetallic components in a pre-treatment process. A pyrometallurgical process is often used tbr RPM recovery, although the expensive equipment required has limited its use in small and medium-sized enterprises. Hydrometallurgical processing is effective and easy to operate, with high selectivity of target metals and high recovery efficiency of RPMs, compared to pyrometallurgy. Biometallurgy, though, has shown the most promise for leaching RPMs from urban mines, because of its low cost and environmental friendliness. Newly developed technologies electrochemical, supercritical fluid, ionic liquid, and mechanochemical have offered new choices and achieved some success in laboratory experiments, especially as efficient and environmentally friendly methods of recycling RPMs. With continuing advances in science and technology, more technologies will no doubt be developed in this field, and be able to contribute to the sustainability of RPM mining.