Carbon Resources Conversion最新文献

The development of a coal-based synthetic route to produce benzene polycarboxylic acids (BPCAs) is of great importance for the highly efficient utilization of lignites. In this paper, aqueous NaCl electrolytic system was used to oxidize Zhaotong lignite to prepare BPCAs. The electrochemical oxidation of lignite in aqueous NaCl solution could produce more BPCAs than that in aqueous NaOH solution. The aqueous NaCl electrolytic system could in-suit produce a stable OCl⁻, which was synthesized by the combination reaction between Cl₂ and OH⁻ generated in the anode or cathode, respectively. The in-suit produced OCl⁻ would degrade the organic structures of the lignite dispersing in the electrolyte to generate BPCAs. The formation of BPCAs could be greatly affected by current density, electrolysis time and the addition amount of NaCl in the electrolytic system, which resulted from that the factors played an important role in the generation of OCl⁻. The coal related model compounds including anthracene and phenanthrene were used to investigate the electrochemical oxidation mechanism of the lignite. The results indicated that the aromatic ring structures in the lignite were attacked by O₂⁻ from the OCl⁻ to afford BPCAs.

Post synthetic modification of a hydrophilic metal–organic framework (MOF), HKUST-1, with stearic acid (SA) was carried out to enhance the stability of HKUST-1 in aqueous solution to be used as a support for formate dehydrogenase (FDH) used for CO₂ conversion to formate. SA modification improved the hydrophobicity without affecting the morphology and crystal structure of MOF. Adsorption of FDH on the modified MOF (SA@HKUST-1) was compared to that of the native HKUST-1 and ZIF-L. The adsorption kinetics on all MOFs was found to follow pseudo-second order kinetics and the isotherm was best described by Freundlich model. The high stability of SA@HKUST-1 and enhanced hydrophobic interaction between support and CO₂ resulted in high catalytic efficiency and stability of FDH@SA@HKUST-1. The immobilized enzyme retained 95.1% of its initial activity after 4 cycles of repeated use. It was also shown that FDH@SA@HKUST-1 retained morphology and crystal structure after repeated use. Results of the present work provide novel insight into the influence of hydrophobic MOFs on the activity and stability of immobilized FDH. These findings are expected to assist in developing highly active and stable biocatalysts for CO₂ hydrogenation at commercial level.

This study reports the valorization of four side-streams derived from the food industry as fermentation media to cultivate edible and medicinal macrofungi of the genera Cyclocybe sp., Ganoderma sp., Grifola sp., Hericium sp., Morchella sp., Pleurotus sp., Schizophyllum sp. and Trametes sp.. Initial screening experiments revealed the suitability of brewer’s spent grain extract (BSGE) and diluted wine distillery effluent (WDE) as the sole carbon sources for significant mycelial mass production. Subsequent fermentations investigated the effect of static and agitated conditions on biomass production, protein content and glucan content of fungal biomass. Considerably higher biomass and concentrations of total glucans, α-glucans and β-glucans were determined in macrofungi cultivated in BSGE compared to WDE. Agitated BSGE-based cultures of Schizophyllum commune resulted in the maximum biomass synthesis (27.6 g/L), while the highest total glucans of 70.8 % w/w with a β-glucan content of 57.2 % w/w were determined for G. lingzhi, when the culture was also agitated. The protein content of mycelia ranged from 12.3 up to 26.5 % w/w in the strains that were examined. ATR-FTIR spectra of the mycelia demonstrated the characteristic bands associated with fungal polysaccharides.

A cheap method allowing fabrication of biocompatible, ultra-small (2–10 nm) and fluorescent (λ_em = 425–500 nm) nanohybrids (NHs) from coffee wastes is reported. The gadolinium-doped nanohybrids (GDNHs) or gadolinium-free carbon dots (GFCDs) can be synthesized in a domestic microwave oven according to green synthesis principles. Hydrodynamic sizes, chemical composition, impact on proton magnetic resonance relaxation time and optical properties of the GDNHs and GFCDs were studied in details and compared. In particular, doping of the NHs with Gd³⁺ ions, up to 1.87 % w/w of gadolinium per particles’ weight, will allow their application for magnetic resonance imaging (MRI). Furthermore, cell culture tests on human adenocarcinomic alveolar basal epithelial cells line (A549) have shown high biocompatibility of the GDNHs and in a wide concentration range 100–1000 µg/ml.

Rapidly increasing plastics have been used and finally become wastes, resulting in increasing pressures to the environment. Microwave-assisted pyrolysis is a promising technology for converting organic wastes as waste plastics into value-added products. At present, many works on microwave-assisted pyrolysis of plastics have been published, but the achievements, challenges, and future directions of microwave-assisted pyrolysis of waste plastics have not been well summarized and discussed. In this work, the principle of microwave-assisted pyrolysis technology is introduced. Then, the progress of its application to recover useful products from plastics is reviewed and discussed in terms of key parameters including microwave power, pyrolysis temperature, reaction time, types of catalyst, microwave absorbents and feedstock mixing ratio. Especially, the yields and properties of the produced oil, gas and char are correlated with the process parameters. Finally, the existing challenges and prospects of disposal/reuse of waste plastics by microwave-assisted pyrolysis technology are discussed.