Salt removal from seawater and brackish water by Capacitive deionization (CDI) is an emerging technology that has a potential to contribute to solving global shortages of freshwater. Upon the application of an external voltage to a pair of nanostructured carbon electrodes, ions are removed by electrosorption in the electrical double layer (EDL) of the capacitor. The physical limitation due to repulsion of co-ions can be reduced using intercalation materials that are less sensitive to ion concentration variations. Herein, we report a hollow-concave high-entropy Prussian blue analogue (HEPBA) enhanced electrodes for superior electrochemical and capacitor performances. The half-cell of hollow-concave HEPBA has a high cycling stability of 1000 cycles at a current density of 1 A g−1. Lower energy consumption for desalination estimated over 90 cycles is due to an enhancement of salt adsorption capacity of HEPBA (∼ 26.2 mg g−1). The observed improvement in the electrochemical property is due to synergistic effects from multi-elemental composition that lead to the high entropy and specific surface area. Hollow-concave HEPBA are structurally stable with negligible changes in the lattice parameters during extensive charging and discharging cycles. This simple method offers an opportunity to modify the structure and morphology of PBAs for real-life applications.

Mandarin oranges are susceptible to senescence and decay, primarily due to postharvest quality loss and fungal infections. This study aim to develop edible and active coatings using carnauba and shellac incorporated with carvacrol nanoemulsion (CNE), and to examine the synergistic effects of the coating on the quality parameters and shelf-life of the mandarin oranges during ambient storage. Nanoemulsion of carvacrol with average droplet size of 348.8 nm was prepared, showing a polydispersity index value of 0.211, showed excellent antifungal activities. Five coating formulations were developed and applied on the mandarin oranges. The coating containing 2 %, v/v CNE exhibited the lowest weight loss (19.23 %), maintaining highest firmness (12.06 N), and total soluble solids of 16.1°Brix, and a titratable acidity of 1.56 % even after 30 days of storage. The application of the coating on the mandarin oranges-maintained quality up to 30 days doubling the shelf-life in the ambient.

Efficient hydrogen production through Methanol Steam Reforming (MSR) is an area of high importance due to its environmental suitability and superior energy efficiency compared to methane steam reforming. Therefore, we present a comprehensive investigation into the development of copper-based catalysts for MSR. Over the past decades, research in this domain has intensified, encompassing Cu-based catalysts that exhibit notable promise. Strategies to enhance catalytic activity and stability involve the utilisation of mesoporous support materials with tuneable properties, novel promoters, and the introduction of mixed oxides and metal organic framework amongst others. Furthermore, the paper underscores the significance of catalyst morphology and metal precursors in determining their final performance. Several new catalysts have shown remarkable selectivity for hydrogen while minimizing carbon monoxide production even at elevated temperatures, positioning them as strong candidates for environmentally friendly commercial hydrogen production through methanol steam reforming. Valuable insights into synthesis approaches and catalyst performance variations across different research groups are also presented.

PEGylation is regarded as a common antifouling strategy and the effect is normally linked with surface hydrophilicity of the coatings. Herein, the biopolymer chitosan (CS) was grafted by polyethylene glycol (PEG) of different chain lengths (molecular weight 200, 4 k and 100 k Da) to verify if the hydrophilicity of CS-PEG coatings is crucial in determining antifouling activities and if PEG chain length influences biofouling in marine environment. Properties of copolymers such as melting points and crystallinity are affected by grafting PEG. The water contact angle (WCA) of CS-PEG coatings increases with the chain length of grafted PEG, from 27° to 58°. Photocatalyst of zinc oxide-silver (ZnO/Ag) was also studied and its embedment (2 % to CS-PEG) renders the surface of CS-PEG coatings more hydrophobic with WCA increased from 52° to 86°. Antibacterial, anti-diatom, and anti-biofilm activities of the coatings were evaluated in natural sea water. The bacterial density on CS-PEG coatings was dramatically reduced to 4 × 104 compared to the control of 7 × 104 ind/mm2, and further to 2 × 104 for CS-PEG-ZnO/Ag coatings. CS-PEG coatings also strongly inhibit diatoms (120–200 ind/mm2), but the inclusion of ZnO/Ag did not obviously enhance such effect (50–150 ind/mm2). The findings provide useful insights for designing polymer-based antifouling coatings.

Chitosan (CS), an edible and non-toxic natural biopolymer, has been widely used in food preservation attributed to its intrinsic antimicrobial, biodegradable, and excellent film-forming properties. In this work, we report photocatalyst-loaded chitosan coating on commercial polyethylene (PE) film with enhanced antimicrobial properties for food packaging application. To improve the chemical stability of zinc oxide (ZnO) photocatalyst in acidic chitosan matrix, a thin layer (1–5 nm) of amorphous tin oxide (SnOx) was coated on ZnO nanoparticles. Consequently, the charge transfer efficiency of ZnO is improved and most of the surface defects are retained according to the studies of UV–Vis and fluorescence spectroscopy. The thin SnOx coating on ZnO was observed by high-resolution transmission electron microscopy (HRTEM) and its effects on crystallinity and particle size of ZnO were examined using X-ray diffraction (XRD) and particle sizer, respectively. The addition of ZnO@SnOx particles in chitosan coating increases water contact angle (WCA) and enhances thermal stability of chitosan coating. The antimicrobial activity of chitosan, ZnO-SnOx nanoparticles, and CS-ZnO@SnOx coated PE films were examined against both Gram-negative (E. coli, A. faecalis) and Gram-positive (S. aureus, B. subtilis) bacteria. Compared to the limited antimicrobial effects of chitosan, ZnO-SnOx demonstrates an improved inhibition effect on bacterial growth over 48 h period under light. For the CS-ZnO@SnOx nanocomposite coated PE films, no inhibition zone was observed due to the limitation of disc diffusion method. Meanwhile, there were no bacterial colonies found to develop on the film, rendering this CS nanocomposite coating a good candidate for food packaging applications.

Green hydrogen production from water is one attractive route to non-fossil fuel and a potential source of clean energy. Hydrogen is not only a zero-carbon energy source but can also be utilized as an efficient storage of electrical energy generated through various other sources, such as wind and solar. Cost-effective and environmentally benign direct hydrogen production through neutral water (similar to pH 7) reduction is particularly challenging due to the low concentration of protons. There is currently a major need for easy-to-prepare, robust, as well as active electrode materials. Herein we report three new molecular electrodes that were prepared by anchoring commercially available, and environmentally benign cobalt-containing electrocatalysts with three different ligand frameworks (porphyrin, phthalocyanine, and corrin) on a structurally modified graphite foil surface. Under the studied reaction conditions (over 7 h at 22 degrees C), the electrode with Co-porphyrin is the most efficient for the water reduction with starting similar to 740 mV onset potential (OP) (vs. RHE, current density 2.5 mA/cm(2)) and a Tafel slope (TS) of 103 mV/dec. It is followed by the molecular electrodes having Co-phthalocyanine [825 mV (OP), 138 mV/dec (TS)] and Vitamin-B-12 (Co-corrin moiety) [830 mV (OP), 194 mv/dec (TS)]. A clear time-dependent improvement (>200 mV over 3 h) in the H-2 production overpotential with the Co-porphyrin-containing cathode was observed. This is attributed to the activation due to water coordination to the Co-center. A long-term chronopotentiometric stability test shows a steady production of hydrogen from all three cathode surfaces throughout seven hours, confirmed using an H(2 )needle sensor. At a current density of 10 mA/cm(2), the Co-porphyrin-containing electrode showed a TOF value of 0.45 s(-1) at 870 mV vs. RHE, whereas the Co-phthalocyanine and Vitamin-B-12-containing electrodes showed 0.37 and 0.4 s(-1) at 1.22 V and 1.15 V (vs. RHE), respectively.

Green hydrogen production via water splitting is vital for decarbonization of hard-to-abate industries. Its integration with renewable energy sources remains to be a challenge, due to the susceptibility to hazardous gas mixture during electrolysis. Here, we report a hybrid membrane-free cell based on earth-abundant materials for decoupled hydrogen production in either acidic or alkaline medium. The design combines the electrocatalytic reactions of an electrolyzer with a capacitive storage mechanism, leading to spatial/temporal separation of hydrogen and oxygen gases. An energy efficiency of 69% lower heating value (48 kWh/kg) at 10 mA/cm2 (5 cm-by-5 cm cell) was achieved using cobalt-iron phosphide bifunctional catalyst with 99% faradaic efficiency at 100 mA/cm2. Stable operation over 20 hours in alkaline medium shows no apparent electrode degradation. Moreover, the cell voltage breakdown reveals that substantial improvements can be achieved by tunning the activity of the bifunctional catalyst and improving the electrodes conductivity. The cell design offers increased flexibility and robustness for hydrogen production.

Edible coatings on fruits and vegetables preserve postharvest quality by reducing water loss and lowering respiration, and metabolic activities. The primary objectives of this study were to develop composite coating formulations using natural waxes (carnauba and shellac wax), eugenol nanoemulsion, and Aloe vera gel, and assess the potential impacts of the coating formulations on the postharvest quality and shelf-life of the Kaji lemon. The results show that eugenol nanoemulsion and Aloe vera gel enhanced the physico-chemical, antimicrobial and antioxidant properties of the developed coating. Notably, the fruits coated with optimized nanocomposite of wax with eugenol and aloe vera gel inclusion (SW + CW/EuNE-20/AVG-2) showed the lowest weight loss (16.56%), while the coatings of wax with only aloe vera gel (SW + CW/AVG-2) exhibited the highest firmness (48 N), in contrast to the control fruit, which had 27.33% weight loss and 9.6 N firmness after 28 days of storage, respectively.

Long-term durability is becoming increasingly relevant for capacitive deionization (CDI) as the technology emerges on the commercial scale. Short-term deionization studies have suggested that Faradaic leakages could be a major factor in electrode degradation, but the long-term effects are still unclear. In this study, we probe the degradation process of the desalination efficiency in commercial CDI modules for up to 52 days of non-stop operation. This corresponds to a little more than 100 m3 of water treated, and the lifetime production volume of the modules is estimated between 150,000–250,000 L of purified water. Surprisingly, the results demonstrate that the absolute long-term loss is largely linear with the cumulative charge leakage. This suggests short-term leakage currents could reasonably predict long-term degradation. Interestingly, the absolute loss mechanisms mean devices with higher total capacitance are more degradation resistant. Finally, shortening cycle times and other methods of reducing leakage would lead to a proportionally longer lifetime. Notably, the first 2 min of the 10 min operation retained 50 % of the performance with only 10 % of the leakage (10-fold reduction). In conclusion, the work provides a method for understanding, predicting, and reducing degradation in long-term operations with commercial CDI modules.

Background: Discharge of large amounts of untreated industrial effluent into water bodies pose significant environmental challenges worldwide. This is due to the limitations of traditional wastewater treatment methods in the treatment of recalcitrant organic pollutants. Fenton processes involves the generation of hydroxyl radicals that are well suited to degrade organics in effluent water. This study focuses on reducing slag generation during Fenton processes and enhancing the reuse of nano-zero-valent iron (NZVI) through the immobilization of NZVI on activated carbon cloth (ACC) through a chitosan (CH) linker with phenol as a model pollutant. Results: Microstructural and spectroscopic techniques were employed to study the materials prepared and 37.5 wt% iron loading was achieved. Phenol degradation of 96.3% at 40 °C at pH of 3.0 with 50 mM H2O2 was achieved using ACC-CH-NZVI. Adsorption and degradation studies carried out using ACC-CH-NZVI catalyst revealed that phenol adsorption onto ACC-CH-NZVI fits the Langmuir isotherm model, following the pseudo-second-order kinetic model and first-order reaction kinetics. Thermodynamic studies indicate the non-spontaneous, endothermic and irreversible nature of the removal process. Comparing ACC-CH-NZVI with ACC and ACC-CH, phenol removal using ACC drops from 87.8 to 39%, while using ACC-CH, the removal efficiency drops from 73 to 20.9% and using ACC-CH-NZVI, phenol removal drops from 96.3 to about 70% and total organic carbon removal drops from 79 to about 60% with minimal iron leaching, highlighting the superior performance of ACC-CH-ZVI and the role of NZVI in enhancing phenol removal. Conclusions: The catalyst demonstrated good stability for phenol degradation to about 70% phenol removal from simulated wastewater and 60% TOC removal from industrial wastewater after five treatment cycles with minimal Fe leaching. Graphical abstract: (Figure presented.)