•Antibacterial ZnO nanoparticles for edible surface coatings were successfully fabricated.•Incorporation of ZnO nanoparticles in a chitosan/gum arabic edible coating was evaluated.•Effects of ZnO ...nanoparticles on the performance of the edible coating for banana preservation were investigated.•Properties of the edible coating and changes in the physical chemical properties of the banana were investigated.•The developed edible coating composite can be applied for banana preservation.
ZnO nanoparticles are nontoxic inorganic oxides that have been extensively used as a supplement for zinc nutrients and antibacterial agents in the food industry, especially in edible coatings to protect food from deterioration by viruses, fungi, and bacteria. In this work, ZnO nanoparticles were fabricated by a hydrothermal method and characterized by scanning electron microscopy and X-ray diffraction. The prepared ZnO nanoparticles exhibited good antibacterial properties against several bacteria, including Staphylococcus aureus, Escherichia coli, and Bacillus subtilis. The ZnO nanoparticles as an antibacterial agent were incorporated into a chitosan/gum arabic (CH/GA) edible coating, and the protective performance for the preservation of bananas was investigated. The obtained CH/GA/ZnO coating significantly improved the quality and shelf life of bananas at a temperature of 35 °C and relative humidity (RH) of 54 %. The banana surface treated with the CH/GA/ZnO coating was relatively smooth with a CH/GA/ZnO film thickness of approximately 50 μm. The utilization of the resultant coating enabled the maintenance of banana quality, including fruit firmness, weight loss, reducing sugar, and titratable acidity, for a remarkably longer period. The banana coated with the CH/GA/ZnO system was demonstrated to maintain freshness for more than 17 d in comparison with the less than 13 d for the control banana at 35 °C and 54 % RH.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Properties and mechanisms of Cr(VI) adsorption onto LDH-based materials reviewed.•Such materials: high anion exchange capacity and positively charged external surface.•Identified mechanism: anion ...exchange, adsorption-coupled reduction, electrostatic attraction.•Adsorption-coupled reduction: identified by some advanced techniques from 2016.•Thermodynamic parameters: ΔG° <0, ΔH° >0, and ΔS° >0 in the most observation cases.
An attempt has been made in this review to provide some insights into the possible adsorption mechanisms of hexavalent chromium onto layered double hydroxides-based adsorbents by critically examining the past and present literature. Layered double hydroxides (LDH) nanomaterials are typical dual-electronic adsorbents because they exhibit positively charged external surfaces and abundant interlayer anions. A high positive zeta potential value indicates that LDH has a high affinity to Cr(VI) anions in solution through electrostatic attraction. The host interlayer anions (i.e., Cl−, NO3−, SO42−, and CO32−) provide a high anion exchange capacity (53–520 meq/100 g) which is expected to have an excellent exchangeable capacity to Cr(VI) oxyanions in water. Regarding the adsorption-coupled reduction mechanism, when Cr(VI) anions make contact with the electron-donor groups in the LDH, they are partly reduced to Cr(III) cations. The reduced Cr(III) cations are then adsorbed by LDH via numerous interactions, such as isomorphic substitution and complexation. Nonetheless, the adsorption-coupled reduction mechanism is greatly dependent on: (1) the nature of divalent and trivalent salts utilized in LDH preparation, and the types of interlayer anions (i.e., guest intercalated organic anions), and (3) the adsorption experiment conditions. The low Brunauer–Emmett–Teller specific surface area of LDH (1.80–179 m2/g) suggests that pore filling played an insignificant role in Cr(VI) adsorption. The Langmuir maximum adsorption capacity of LDH (Qomax) toward Cr(VI) was significantly affected by the natures of used inorganic salts and synthetic methods of LDH. The Qomax values range from 16.3 mg/g to 726 mg/g. Almost all adsorption processes of Cr(VI) by LDH-based adsorbent occur spontaneously (ΔG° <0) and endothermically (ΔH° >0) and increase the randomness (ΔS° >0) in the system. Thus, LDH has much potential as a promising material that can effectively remove anion pollutants, especially Cr(VI) anions in industrial wastewater.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Gold nanoparticles (AuNPs) decorated CNTs are promising materials for photocatalytics and biosensors. However, the synthesis of AuNPs chemically linked to the walls of MWCNTs is challenging and toxic ...products such as thionylchloride (SOCl
) or 1-ethyl-3(dimethyl-amino) propyl carbodiimide hydrochloride (EDAC) need to be used. This work reports a new approach to prepare gold nanoparticles decorated multiwalled carbon nanotubes (MWCNTs) by using cysteaminium chloride via the formation of a Zwitterionic acide-base bond. The grafting process consists of 3 mains steps: oxidation, thiolation and decoration of AuNPs on the surface of MWCNTs. The completion of each step has been verified out by both spectroscopic (Raman, UV-Vis, FT-IR) and Scanning Electron Miscroscopy (SEM). The chemical bonding states of synthesized products have been proven by X-ray photoelectron spectroscopy (XPS).
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
An hybrid system of combined plasma with photocatalysis for treatment of hospital indoor air.
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•A possible way for treatment of air from hospitals and swimming pools is proposed.•The ...destruction of CVOC in air by photocatalysis and plasma and coupling is studied.•The synergistic effect of the combined system is observed.•The effects of operating parameters on the performance of each process are tested.•TiO2 + UV showed high performance in the mineralization and ozone elimination.
The purpose of this study is to evaluate the efficiency of non-thermal plasma and heterogeneous photocatalysis processes for indoor air treatment using cylindrical continuous reactor at pilot scale and high flow rates. Trichloromethane (CHCl3) also called chloroform was chosen as a model pollutant representing hospital indoor air. This pollutant is considered as carcinogenic, mutagenic and reprotoxic agent. The effect of several parameters such as inlet pollutant concentrations (25–300 mg m−3), flow rates (2–8 m3 h−1), relative humidity of the effluent (5, 30, 50 and 90%) as well as input of the plasma discharge (9–21 kV) on the photodegradation of trichloromethane is investigated.
Our findings show that the increase of flow rate leads to a reduction of degradation efficiency, while the humidity promotes the degradation in the case of photocatalysis process due to the formation of OH radicals.
Moreover, the addition of a photocatalyst under UV radiation in the discharge zone enhances the reduction of ozone and CO gases compared to plasma process alone.
The combination of plasma DBD and photocatalysis enhances the removal efficiency with a synergetic effect, leading to removal efficiency higher than 10% if we consider the sum of the contribution of each process separately.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
This work aims to clarify the photocatalytic degradation mechanism and heat reflectance recovery performance of waterborne acrylic polymer/ZnO nanocomposite coating. To fabricate the nanocomposite ...coating, ZnO nanoparticles (nano‐ZnO) were dispersed into acrylic polymer matrix at the various concentrations from 1 to 6% (by total weight of resin solids). The photocatalytic degradation of nanocomposite coating under ultraviolet (UV) light irradiation has been investigated by monitoring its weight loss and chemical/microstructural/morphological changes. As the topcoat layer, its heat reflectance recovery has been evaluated under UV/condensation exposure by using an artificial dirty mixture of 85 wt% nanoclay, 10 wt% silica particles (1–5 μm), 1 wt% carbon black, and 2 wt% engine oil. After 108‐cycle UV/condensation exposure, infrared spectra and weight loss analysis indicated that the maximal degradation for nanocomposite coating is observed at 1 wt% nano‐ZnO. On the other hand, after 96 hr of UV light exposure, the nanocomposite coating with1 wt% nano‐ZnO could restore effectively the reflective index of solar‐heat reflectance coating (from 58.45 to 80.78%). Finally, the photodegradation mechanism of this waterborne acrylic polymer coating has been proposed as the UV‐induced formation of CCCO conjugated double bonds. As a result, its self‐cleaning phenomenon can be achieved as the recovery of heat reflectance.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Dy addition reduces Ni crystallite size and improve its dispersion on Ni/SiC-SiO2.•0.5 %Dy-10 %Ni/SiC-SiO2 achieves 100 % CH4 selectivity and 73.9 % CO2 conversion at 350 °C.•Microwave heating ...outperforms electric, yielding higher CO2 conversion.•Extreme SiC dilution hampers CO2 conversion and CH4 selectivity in both reactors.•Carbon formation in the microwave reactor quantified at only 0.0099 mgC/gcat/h.
In this work, Dy-promoted Ni/SiC-SiO2 catalysts with varied Dy loadings (0–1 %) were developed using the wet impregnation method and evaluated for their effectiveness in CO2 methanation. The characterization results reveal that Dy addition can reduce the Ni crystallite size, enhance the dispersion of active phase and increase the catalyst’s reducibility. Among the prepared catalysts, the 0.5 %Dy-10 %Ni/SiC-SiO2 demonstrated the highest CH4 selectivity (100 %) and CO2 conversion (73.9 %) at 350 °C owing to its highest basic sites and H2 chemisorption capacity. The performance of this Dy-promoted catalyst diluted with different amounts of SiC, which was employed as a microwave susceptor and high thermal conductive dilution material, was also investigated in both microwave and electric reactor. Microwave heating leads to higher CO2 conversion compared to electric heating, regardless of reaction temperature and dilution factor due to selective heating and the random occurrence of hot spots, which are usually considered as micro-plasmas in the catalyst bed. However, further increase quantity of SiC decreased both CO2 conversion and CH4 selectivity regardless of heating method. This may be attributed to the appearance of extreme overheating and the absence of gentle overheating with increased amount of SiC in the microwave and electric reactors, respectively. The temperature-programmed oxidation results demonstrated that carbon deposition on the 0.5 %Dy-10 %Ni/SiC-SiO2 catalyst during 30 h of reaction can be significantly suppressed by microwave.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Working in academia is challenging, even more so for those with limited resources and opportunities. Researchers around the world do not have equal working conditions. The paper presents the ...structure, operation method, and conceptual framework of the SM3D Portal's community coaching method, which is built to help Early Career Researchers (ECRs) and researchers in low-resource settings overcome the obstacle of inequality and start their career progress. The community coaching method is envisioned by three science philosophies (cost-effectiveness, transparency spirit, and proactive attitude) and established and operated based on the Serendipity-Mindsponge-3D knowledge (SM3D) management framework (i.e., mindsponge thinking and Bayesian Mindsponge Framework analytics serve as the coaching program's foundational theory and analytical tools). The coaching method also embraces Open Science's values for lowering the cost of doing science and encouraging the trainees to be transparent, which is expected to facilitate the self-correcting mechanism of science through open data, open review, and open dialogue. Throughout the training process, members are central beneficiaries by gaining research knowledge and skills, acquiring publication as the training's product, and shifting their mindsets from “I can't do it” to “I can do it,” and at the same time transforming a mentee to be ready for a future mentor's role. The coaching method is thus one of the members, for the member, by the members.•The paper provides the structure, operation method, and conceptual framework of the SM3D Portal's community coaching method, which is built to help Early Career Researchers (ECRs) and researchers in low-resource settings overcome the obstacle of inequality and start their career progress.•The paper presents three major science philosophies envisioning the establishment and operation of scholarly community coaching.•The paper employs the mindsponge theory and BMF analytics to construct a conceptual framework explaining how an environment is created to help shift members’ mindsets from “I can't do it” to “I can do it.”
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Salinity intrusion is a complex issue in coastal and estuarine areas. Currently, remote sensing techniques have been widely used to monitor water quality changes, ranging from inland river networks ...to deep oceans. The Vietnamese Mekong Delta is an important rice-growing area, and intrusion of saline water into irrigated freshwater-based agriculture areas is one of the most crucial constraints for agriculture development. This study aimed at building a numerical model to realize the salinity intrusion through the relationship between reflectance from the Landsat-8 Operational Land Imager images and salinity levels measured in situ. A total of 103 observed samples were divided into 50% training and 50% test. Multiple Linear Regression, Decision Trees and Random Forest (RF) approaches were applied in the study. The result showed that the RF approach was the best model to estimate salinity along the coastal river network in the study area. However, the large samples size needed was a significant challenge to circumscribe predicting ability of the RF model. The reflectance has a good correlation with salinity when locations (latitude-longitude) of salinity measured stations were added as a parameter of the Step-wise model with R-square 77.48% in training and 74.16% in test while Root Mean Square Error was smaller than 3.
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BFBNIB, GIS, IJS, KISLJ, NUK, PNG, UL, UM, UPUK
The crystallization and segregation behavior of immiscible polycaprolactone/poly(ethylene glycol) PCL/PEG (50/50) blends was investigated using mainly resonance-enhanced atomic force microcopy ...coupled with infrared spectroscopy (AFM-IR) which allows a spatial resolution of the order of 30–50 nm. Chemical infrared images of the blends at different scales highlight their island-like spherulitic structures. The nanoscale IR spectra on both sides of the spherulitic interfaces are different. The polymer segregation mechanism of the blend in the spherulitic structure is also investigated in which PEG is rejected outside of PCL spherulites at low crystallization temperature (30 °C) while it is rejected in the form of small nodules with a dimension in the order of few micrometers, inside of PCL spherulites at higher crystallization temperature (40 °C) due to the presence of an upper critical solution temperature (UCST).
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IJS, KILJ, NUK, PNG, UL, UM
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