V ₂ O ₅ /carbide-derived carbon core–shell hybrid electrodes can be synthesized using vanadium carbide as the precursor. The resulting hybrid material shows high energy and power ratings for electrochemical energy storage.

The separation of CO₂/CH₄ using porous carbon can be increased by the presence of a functional group of nitrogen on the carbon surface. This study explores the potential of porous carbon derived from the palm kernel shell (C-PKS) impregnated with a deep eutectic solvent (DES), which is one of the chemicals containing a nitrogen element. The DES was composed of a quaternary ammonium salt of choline chloride (ChCl) and a hydrogen bond donor of alcohol. Three alcohols of 1-butanol (-ol), ethylene glycol (-diol), and glycerol (-triol) were employed to study the effects of a number of hydroxyl groups in the separation performance. The research steps included (i) the preparation of DES-impregnated porous carbon synthesized from the palm kernel shell (DES/C-PKS), (ii) characterization of the material, and (ii) a separation test of CO₂/CH₄ with a breakthrough system. Materials were characterized using scanning electron microscopy (SEM) combined with energy-dispersive X-ray spectroscopy (EDX), N₂-sorption analysis, and Fourier transform infrared (FTIR) spectroscopy. SEM images showed a significant morphological difference of pristine carbon and DES/C-PKS. There was a significant decrease in the range of 67–73% of a specific surface area with respect to pristine carbon, having initially 800 m²/g. However, the N element on the carbon surface increased after impregnation treatment, which was shown from the intensity of the FTIR graphs and EDX analysis. Adsorption isotherm revealed that DES/C-PKS could enhance up to 1.6 times the adsorption capacity of CO₂ at 1 atm and 30 °C while increasing the selectivity of CO₂/CH₄ up to 125%. The breakthrough experiment showed that all DES/C-PKS materials displayed a better performance for the separation of CO₂/CH₄, indicated by a longer breakthrough time and enhancement of CO₂ uptake. The best separation performance was achieved by DES/C-PKS using glycerol as a hydrogen bond donor with 15.4 mg/g of CO₂ uptake or equivalent to 95% enhancement of the uptake capacity compared to pristine porous carbon. Also, the cycling test revealed that DES/C-PKS can be used repetitively, which further highlights the efficiency of the material for the separation of CO₂/CH₄.

Fruit waste is a part of municipal solid waste which is typically disposed of directly to a landfill site. In order to utilize this valuable renewable resource, anaerobic biological processes can be employed to convert fruit waste to biogas. This usable gas is then used to generate electricity. This paper describes a comprehensive study to set up technology for converting fruit waste to electricity via biogas production. First, the fruit waste characteristics (type and composition) were systematically evaluated, and then laboratory experiments for biogas conversion to explore gas production from the waste were carried out. The biogas plant was then designed, based on the information obtained. Finally, a comparison of biogas plant with landfill was performed using life cycle assessment (LCA) to determine environmental impacts, and economic evaluation to assess daily processing costs. The results from waste characterization in one of the biggest fruit markets in Indonesia showed that the three main component fruit types were orange (64%), mango (25%), and apple (5%). Rotten fruit contributes up to 80% of the total waste in the fruit market. Based on the experimental work, the potential gas production in the biogas plant was calculated to be approximately 1075 Nm3/day, comprising 54% methane, based on 10 tons per day of fruit waste. The comparison demonstrates that it is a better option to utilize fruit waste in a biogas plant, in terms of LCA and daily operational costs, than to dispose of it in landfill.