• Energy Research

Natural gum derived from the natural surrounding (gum arabic, guar gum, xanthan gum, gellan gum, fenugreek gum, karaya gum, and acacia gum) is one of the most abundant polysaccharides currently present around the world. As natural gum dissolved solution can be very sticky in nature, its role as a binder for both anodes and cathodes in rechargeable batteries have been recently significantly researched. Although much research has been delved into using natural gum as a feasible binder for rechargeable batteries, little investigation so far has taken place to compile, summarize, analyze, and evaluate the current status-quo of the natural gum-based binder research, as well as understanding some of the obstacles and issues that may need to be addressed. This review gives a comprehensive review on the natural gum-based binder that was used for both anode and cathode in rechargeable batteries and how each kind of natural gum improved the electrochemical performance in terms of cycle retention and rate capabilities. Furthermore, more systematic analysis and future projections for the research on natural gum-based binders are presented, which will serve to further the promising research related to utilizing natural gum as an efficient binder for rechargeable battery systems.

An economical and easy one-step method for the biosynthesis of highly stable molybdenum trioxide (MoO3) nanoparticles was developed using gum arabic as a bio-template; ensuing nanoparticles (NP) were characterized by X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, UV–visible spectroscopy, transmission electron microscopy (TEM) and energy-dispersive X-ray spectroscopy (EDX). The crystallinity and purity of MoO3 nanoparticles in the orthorhombic phase were confirmed by XRD analysis, and their rod-shaped identity (average sizes ranging from 7.5 to 42 nm) were observed by TEM. Cytotoxic effects of the NP were monitored using Hep G2 (human liver cancer) and HEK 293 (human embryonic kidney) cell lines via 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assays. The results of this study revealed that MoO3 nanoparticles are nontoxic towards Hep G2 cell lines and displayed negligible toxicity, even at very high concentrations (1000 ppm), although had moderate toxicity towards HEK 293 cells. Furthermore, their catalytic activity was evaluated for the reduction of p-nitrophenol to p-aminophenol. Synopsis: Green synthesis of MoO3 nanorods using gum arabic demonstrated as an eco-friendly catalyst for the conversion of p-nitrophenol with negligible toxicity towards Hep G2 cell lines.

Abstract The technological concept ensuring highly efficient co-digestion of by-products from the production of biodiesel and sewage sludge was examined. Rapeseed cakes (RC) 1–5% addition to waste activated sludge (WAS) 95–99% in digesters, positively influenced the degree of biodegradation of organic matter and the quantity and quality of the biogas produced. Under the optimal conditions (HRT = 20–22 days), the co-digestion mixtures (WAS + microwave disintegration + RC) generated double the amount of biogas, containing approximately 10–12% more CH4, than the samples which had the sewage sludge only. Under these conditions, the biogas yield increased by approximately 48–82% depending on the co-substrate used and was further improved via the introduction of microwave pre-treatment. After testing at the pilot scale, this method could be considered as a sustainable alternative to conventional methods for WAS and RC treatment.

Due to rapid urbanization, the number of wastewater treatment plants (WWTP) has increased, and so has the associated waste generated by them. Sustainable management of this waste can lead to the creation of energy-rich biogas via fermentation processes. This review presents recent advances in the anaerobic digestion processes that have led to greater biogas production. Disintegration techniques for enhancing the fermentation of waste activated sludge can be apportioned into biological, physical and chemical means, which are included in this review; they were mainly compared and contrasted in terms of the ensuing biogas yield. It was found that ultrasonic- and microwave-assisted disintegration provides the highest biogas yield (>500%) although they tend to be the most energy demanding processes (>10,000 kJ kg−1 total solids).