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The enhancement of carbon-supported components is a crucial factor in augmenting the interplay between carbon-supported and metal-active components in the utilization of catalysts for direct ethanol fuel cells (DEFCs). Here, we propose a strategy for designing a catalyst by modifying candle soot (CS) and loading nickel onto ordered carbon soot. The present study aimed to investigate the effect of the Ni nanoparticles content on the electrocatalytic performance of Ni–CS, ultimately leading to the identification of a maximum composition. The presence of an excessive quantity of nickel particles leads to a decrease in the number of active sites within the material, resulting in sluggishness of the electron transfer pathway. The electrocatalyst composed of nickel and carbon support, with a nickel content of 20 wt%, has demonstrated a noteworthy current activity of 18.43 mA/cm2, which is three times that of the electrocatalyst with a higher nickel content of 25 wt%. For example, the 20 wt% Ni–CS electrocatalytic activity was found to be good, and it was approximately four times higher than that of 20 wt% Ni–CB (nickel–carbon black). Moreover, the chronoamperometry (CA) test demonstrated a reduction in current activity of merely 65.80% for a 20 wt% Ni–CS electrocatalyst, indicating electrochemical stability. In addition, this demonstrates the great potential of candle soot with Ni nanoparticles to be used as a catalyst in practical applications. [ABSTRACT FROM AUTHOR]

Activated carbon derived from biomass sources is one of the most promising adsorbents for carbon dioxide (CO2) capture because it is inexpensive, effective, and environmentally friendly. The increment of CO2 in the atmosphere is the root cause of numerous climate change-centric environmental problems, in which one of the major CO2 emission sources is known to be the fossil-fuelled power plant. The most mature CO2 capture system (post-combustion capture) of fossil-fuelled power plants involves capturing CO2 from flue gas at low CO2 composition (5-15 wt%), with the remaining gas composed mainly of nitrogen (N2). Hence, this study investigated the effect of the CO2 and N2 gas compositions on the binary CO2-N2 adsorption performances of the activated carbon derived from pomelo peel (PP). Moreover, the comparison of the adsorption performance between pomelo peel-based activated carbon (PPAC) and commercial activated carbon (COMM-AC) was also evaluated. Besides that, PP and PPAC were also characterized through Fourier Transform Infrared (FTIR), XRay Diffraction (XRD), and Brunauer-Emmett-Teller (BET) analysis. The results demonstrated that PPAC has a low graphitization degree and possess a microporous-mesoporous structure, with the pores mainly composed of micropores. The attained results on the effect of the gas compositions showed that higher CO2 gas composition leads to a higher binary CO2-N2 uptake, indicating that PPAC is more selective towards CO2 than N2. By comparing the adsorption performance of PPAC and COMM-AC, it was inferred that COMM-AC is a superior adsorbent at a higher pressure and CO2 composition condition. In contrast, PPAC was found to be a better adsorbent at a lower pressure and CO2 composition condition. These results signified that PPAC is a potential adsorbent for CO2 gas, especially in post-combustion flue gas conditions. [ABSTRACT FROM AUTHOR]

Oil pollution from food industries is one of the major environmental concerns nowadays. Improper management and disposal of cooking oils into the drainage system can have undesirable effects on the environment. However, one of the best ways to treat oil pollution is adsorption using activated carbon. In this study, rubber seed kernels (RSKs) were used to produce activated carbon via impregnation with 10 and 15 wt.% phosphoric acid (H3PO4). Then, the chemically impregnated RSKs were carbonised at 300, 400, and 500 °C for 1.5 h. The performance of the synthesised rubber seed kernel activated carbon (RSKAC) was evaluated based on its oil adsorption capacity. Samples of raw RSKs and RSKAC were analysed using Scanning Electron Microscopy (SEM) and Fourier-transform Infrared (FTIR) spectroscopy. The results showed that RSK sample impregnated with 10 wt.% H3PO4 and carbonised at 500 °C has the highest oil adsorption capacity of 0.896 ± 0.042 g/g. The SEM results showed that the RSKAC sample has more pores than the RSK sample. FTIR spectra of RSKAC revealed that peaks associated with four functional groups (O-H, C-H, C-O, and C=O) were reduced, or disappeared after undergoing H3PO4 activation. These findings revealed that RSKAC has the potential to be utilised as an adsorbent for oil adsorption. [ABSTRACT FROM AUTHOR]

Photocatalysis technology is gaining interest as an alternative wastewater treatment due to its fast and complete pollutants removal advantages. It utilizes light energy and semiconductor catalysts to degrade organic pollutants such as paracetamol (PCM), a common household medication drug. Pharmaceutical wastewater may cause significant hazards to humans and the environment if no advanced treatment is applied. In this study, zinc oxide/silver (ZnO/Ag) nanocomposite was biosynthesized using banana peel extract (BPE) and low Ag content (1 mM and 3 mM) as biomaterial via sol-gel and precipitation for photocatalytic degradation of PCM. Fourier Transform Infrared Spectrophotometer (FTIR) analysis showed a sharp peak of Zn-O band for all catalysts with the success of BPE incorporation. The band gap energy of ZnO/Ag was 3.281 eV, increasing with Ag content. Field Emission Scanning Electron Microscope (FESEM) images of ZnO/Ag exhibit a smaller size of 29.49 nm and a distinct spherical shape. The uniform shape of biosynthesized ZnO/Ag confirms the roles of BPE as stabilizing and capping agents. The highest photocatalytic degradation of PCM was 76% with a reaction constant of 0.0086 min-1 when ZnO/Ag was used as a catalyst, compared to the pristine ZnO was 70%. The asprepared ZnO/Ag nanocomposite from organic solid waste has a high potential for being reutilized as an advanced catalyst for pharmaceutical wastewater treatment. [ABSTRACT FROM AUTHOR]

Wastewater contaminated with oil discharged from food processing industries need to be treated properly in order to avoid clogging the drainage and sewerage systems. The removal of oil via the adsorption technique using biomass as a low-cost adsorbent was proposed in this study. Rubber seed kernels (RSKs) were used as the raw material to synthesise activated carbon. The RSKs were impregnated with 10 wt% of phosphoric acid (H3PO4) and carbonised at 500 °C to produce rubber seed kernel activated carbon (RSKAC). Different parameters were included in batch adsorption studies, namely, contact time (30 to 240 min), activated carbon dosage (0.5 to 2.5 g), and temperature (25 to 65 °C). The performance of each process parameter was evaluated based on the adsorption capacity of oil onto the synthesised RSKAC. Pseudo-first order and pseudosecond order models were applied to analyse oil adsorption kinetics using RSKAC. Based on the experimental results, the highest oil adsorption was achieved at 150 min of contact time, 2.5 g of RSKAC, and at a temperature of 35 °C. Oil adsorption using RSKAC in this study followed the pseudo-second order kinetics model. These findings revealed that RSKAC could be synthesised as a low-cost adsorbent for oil adsorption. [ABSTRACT FROM AUTHOR]

A selective composite membrane for vanadium redox flow battery (VRFB) was successfully prepared by layer-by-layer (LbL) technique using a perfluorosulfonic sulfonic acid or Nafion 117 (N117). The composite membrane referred as N117-(PEI/GO)n, was obtained by depositing alternating layers of positively charged polyethylenimine (PEI) and negatively charged graphene oxide (GO) as polyelectrolytes. The physicochemical properties and performance of the pristine and composite membranes were investigated. The membrane showed an enhancement in proton conductivity and simultaneously exhibited a notable 90 % reduction in vanadium permeability. This, in turn, resulted in a well-balanced ratio of proton conductivity to vanadium permeability, leading to high selectivity. The highest selectivity of the LbL membranes was found to be 19.2 x 104 S.min/cm3, which is 13 times higher than the N117 membrane (n = 0). This was translated into an improvement in the battery performance, with the n = 1 membrane showing a 4-6 % improvement in coulombic efficiency and a 7-15 % improvement in voltage efficiency at current densities ranging from 40 to 80 mA/cm2. Furthermore, the membrane displayed stable operation over a long-term stability at around 88 % at a current density of 40 mA/cm2, making it an attractive option for VRFB applications using the LbL technique. This is because the use of PEI/GO bilayers maintained high proton conductivity and VE of the battery, opening up possibilities for further optimization and improvement of VRFBs. [ABSTRACT FROM AUTHOR]

A selective composite membrane for vanadium redox flow battery (VRFB) was successfully prepared by layer-by-layer (LbL) technique using a perfluorosulfonic sulfonic acid or Nafion 117 (N117). The composite membrane referred as N117-(PEI/GO) n , was obtained by depositing alternating layers of positively charged polyethylenimine (PEI) and negatively charged graphene oxide (GO) as polyelectrolytes. The physicochemical properties and performance of the pristine and composite membranes were investigated. The membrane showed an enhancement in proton conductivity and simultaneously exhibited a notable 90% reduction in vanadium permeability. This, in turn, results in a well-balanced ratio of proton conductivity to vanadium permeability, leading to high selectivity. The highest selectivity of the LbL membranes was found to be 19.2 × 10 4 S.min/cm 3 , which is 13 times higher than the N117 membrane ( n  = 0). This was translated into an improvement in the battery performance, with the n  = 1 membrane showing a 4-6% improvement in coulombic efficiency and a 7-15% improvement in voltage efficiency at current densities ranging from 40 to 80 mA/cm 2 . Furthermore, the membrane displays stable operation over a long-term stability at around 88% at a current density of 40 mA/cm 2 , making it an attractive option for VRFB applications using the LbL technique. The use of PEI/GO bilayers maintains high proton conductivity and VE of the battery, opening up possibilities for further optimization and improvement of VRFBs., Competing Interests: No potential conflict of interest was reported by the author(s)., (© 2024 The Author(s). Published by National Institute for Materials Science in partnership with Taylor & Francis Group.)