Electronic waste (e-waste) management is a critical global pollution concern. This study investigates government support; local residents' perceptions, knowledge, attitudes, and behaviors related to e-waste management; and collaborative governance in southern Thailand. Employing both quantitative and qualitative methods, this research involves expert government officers who are well versed in e-waste management and local residents. The study utilized in-depth interviews, questionnaires, and workshops. The results revealed that the government is responsible for four e-waste management approaches, encompassing various e-waste collection, transportation, and disposal methods. Local residents exhibited low perceptions of e-waste news but possessed substantial knowledge and positive attitudes toward e-waste management. Surprisingly, general characteristics do not significantly influence e-waste management behavior. A statistically significant connection was found between perceptions (B = 0.065, t = 6.657, p value = 0.000) and attitudes (B = 0.079, t = 4.350, p value = 0.000) toward e-waste management, which had a positive relationship with e-waste management behavior in southern Thailand (p value < 0.01). Repairing appliances is the most common action taken (44.5%). Despite longer lifespans for electronic appliances than they did a decade ago, revisions to the draft waste electrical and electronic equipment Act are underway, aiming to incorporate stakeholder involvement and the extended producer responsibility principle. This study provides valuable insights into government and local community concerns regarding e-waste management and evaluates the efficacy of recent management procedures. These findings can inform the development of action plans that consider crucial aspects of e-waste management.

Due to the proximity of Thailand being near the equator, there is a significant potential for harnessing an excess amount of solar energy using a solar collector. The solar collector harvests solar energy by acting as a passive heat exchanger, receiving solar energy, and transferring it to a fluid medium to be further utilized. This study presents the analysis of temperature outlet and pressure drop of a solar collector in Thailand, utilizing Earth’s geological location, date, and time for solar energy calculations and employing computational fluid dynamics (CFD) to predict the collector’s efficiency. The CFD approach offers a reduction in the cost of experiments and environmental impact by minimizing waste from constructing experimental prototype equipment. A closed loop solar collector for a water heater system with the width of 100 mm and the length of 1,000 mm made with copper is selected for this study. The boundary conditions of the model are collected from the experimental data to ensure high accuracy during the validation process. The grid independence is done to ensure high accuracy simulation with CFD. The study also compares the collector performance with another geological location and with different water mass flow rates in the range of 0.554 to 2.582 g s-1. The results confirm the potential of solar collectors in Thailand by achieving efficiency an of 69.61% at 11 a.m. with 2.332 g s-1of mass flow rate.

Investigating the composition of household dust can provide crucial insights into potential environmental and health implications. This study aimed to determine the concentration of selected metals in 30 household floor dust samples collected from two cities in Peninsular Malaysia, namely Melaka and Butterworth. The samples were collected using nylon socks attached to a vacuum cleaner nozzle during January-February 2021. All samples were sieved through a 200-µm sieve, acid-digested with aqua regia, and analyzed using inductively coupled plasma mass spectrometry (ICP-MS). Mean metal concentrations decreased in the order of Fe>Al>Mg>Zn>Mn>Ba>Cu>Cr>Pb. Cd was not detected in any samples. The median concentrations of Al, Ba, and Mg from Melaka were significantly higher than those from Butterworth. Hazard indexes for all metals were less than one, indicating a low noncarcinogenic risk of exposure to occupants via inhalation, dust ingestion, and skin absorption. Statistical analyses revealed that the levels of metals in household dust were influenced by factors such as the location and age of the house, the presence of air conditioning, and the time since the last paint. This study highlights the presence of metals in indoor settings of different cities in Malaysia, providing fundamental data for future research in the field.

The optimal conditions for laccase production and vinasse biotreatment with a native strain of Trametes villosa were determined by a screening-optimization approach. Eleven factors including nutrient concentration, vinasse dilution (%v/v), inoculum volume, carbon to nitrogen ratio and initial pH, were investigated for their effects on laccase activity applying the Plackett-Burman screening design. The selected factors were optimized using a central composite design, and then evaluated on a vinasse biotreatment experiment. The factors that contributed the most to the enzymatic activity were the concentrations of MgSO4∙7H2O (A), FeSO4∙7H2O (B) and CuSO4∙5H2O (C), alongside initial pH. After 10 days, laccase activity was 544.038 U L-1 for the following concentrations of A, B and C: 0.250 g L-1, 0.020 mg L-1, and 0.100 g L-1, respectively. Vinasse biotreatment under optimized conditions resulted in 82.74%, 78% and 75.97% of phenol, color, and COD removal respectively, while final pH value was 6.90. These results showed that the native strain of T. villosa has a good potential for further research on laccase production and vinasse sustainable management.

Magnesium (Mg) is an essential macronutrient for plants. Even though Sri Lankans consume rice as the staple food, the Mg status in Sri Lankan paddy soils as affected by its climate, soils, and water sources used are not well understood. This study was conducted to (i) determine the distribution of exchangeable Mg (ex-Mg) concentration, and (ii) examine the interactive effects of agro-climatic zones (ACZs), soil order, and water source in determining the ex-Mg concentra-tion in lowland paddy fields of Sri Lanka. A total of 9,038 soil samples representing six ACZs, six soil orders, and three water sources were collected using a stratified random sampling approach. The ex-Mg concentration was determined after extracting in 0.01 M CaCl2 and detected using inductively coupled plasma-mass spectrometry. The range of ex-Mg was within 0.01-1,610 mg kg-1, with a mean of 210.4 mg kg-1. From the tested soil samples, 66% were Mg-deficient (<240 mg kg-1), 32% were Mg-optimal (240-730 mg kg-1) and 2% were Mg-excessive (>730 mg kg-1). Among the ACZ, the Dry zone Low country had the highest ex-Mg concentration (p<0.05). Among the soil orders tested, Vertisols had the highest and Histosols had the lowest ex-Mg concentration (p<0.05). Irrigated rice fields had higher ex-Mg than the rainfed systems (p<0.05). Soil ex-Mg concentration was positively correlated with soil pH (p<0.05) and crop productivity (p<0.05). As most rice-growing soils of Sri Lanka are Mg-deficient, it is important to implement strategies specific to ACZs, soil orders, and water sources to improve the soil-Mg status.

Fe3O4/thiamine particles were prepared in this work via precipitation method. The synthesis method is based on the principle of precipitation of Fe3O4 particles in the presence of thiamine coating agent. Also, the potential application of Fe3O4/ thiamine in the removal of methylene blue (MB) was investigated. Several factors that affect the synthesis of Fe3O4/thiamine such as base concentration, mass ratio of FeCl2 to thiamine, reaction temperature, and reaction time were determined. Optimal conditions for preparing Fe3O4/thiamine are NH4OH concentration = 10%, mass ratio of FeCl2:thiamine = 5:1 (g g-1), reaction temperature = 30 °C, reaction time = 120 min. The average particle size of Fe3O4/thiamine is 293.7 nm while the specific surface area, pore diameter, and magnetization of the obtained Fe3O4/ thiamine particles are 57 m2 g-1, 192.67 Å, and 2.4 emu g-1, respectively. The interesting point of this work is to obtain the Fe3O4/thiamine at low temperature with less amount of NH4OH used. Furthermore, 79.08% of MB could be removed using Fe3O4/thiamine as an adsorbent, with a maximum adsorption capacity of 31.63 mg g-1 at pH of 10, a MB concentration of 50 mg L-1, and an adsorption time of 15 min. Adsorption kinetics studies showed that the pseudo-second-order model fitted the experimental data better than the pseudo-first-order and the adsorption process is physical adsorption following the Freundlich adsorption isotherm model. An adsorption mechanism of MB onto Fe3O4/thiamine was also suggested. The synthesized Fe3O4/ thiamine particles could be a potential material for treating wastewater.

In this study, the CaO adsorbent was prepared by using local waste eggshell as a raw material. The influence of preparation parameters including calcination temperature, calcination time and particle size of eggshell powder on the adsorption surface area were investigated. By means of statistically experiment design, the interesting parameters were investigated by a full 23 factorial design. The prepared sorbent material was characterized by X–ray diffraction (XRD), Scanning electron microscopy (SEM) and the Brunauer–Emmet–Teller (BET). The results showed the particle size of eggshell powder greatly affected the BET surface area. By applying the prepared condition of 149 μm in particle size, 6 h of calcination time and 1,000oC calcination temperature, the obtained CaO adsorbent yielded the highest in BET surface area of 5.023 m2 g-1. The CO2 performance test in the fluidized bed reactor with 12% V/V CO2 in N2 balance also revealed that the local waste eggshell can be used as CO2 adsorbent. The CO2 carrying capacity of the highest BET surface area sorbent was 0.011 g CO2 g-1 sorbent at 700°C carbonation temperature.

The optimal conditions for vanillin production from lignin depolymerization using CuO/Al2O3 catalysts were determined by combining Box-Behnken design (BBD) and response surface methodology (RSM). Independent variables, including temperature (80–140 °C), NaOH loading (0.5–1.5 g), time (30–90 min), and catalyst weight (0.5–1.5 g), were investigated to determine the optimal conditions, with the concentration of vanillin being the dependent variable. A CuO/Al2O3 catalyst was prepared by impregnation method. The vanillin obtained from the reaction was analyzed using high-performance liquid chromatography (HPLC). The maximum obtained vanillin concentration of 59.14 mg·L-1 was achieved with a temperature of 80 °C, a reaction time of 90 min, NaOH loading of 1.5 g, and 1.5 g of catalyst. The amount of NaOH was the most influential factor governing the obtained vanillin concentration. Regression analysis was performed to determine the formula describing the vanillin concentration in terms of the independent variables with a reasonable degree of accuracy (R2 = 0.87). This study shows that the optimal conditions for the depolymerization of lignin to vanillin over a CuO/Al2O3 catalyst can be achieved under milder conditions than those reported previously.

As developing dynamic regions, coastal areas have a high potential for environmental incidents, especially chemical spills, which may permanently threaten livelihoods and coastal ecosystems. Establishing an appropriate methodological framework for assessing environmental incidents in coastal areas, ensuring increased predictability and minimising potential consequences is a trend of interest to scientists. In this study, the environmental risk assessment model was applied to develop a framework for assessing environmental incidents in coastal areas due to chemical spills from the mainland based on hazard, exposure and vulnerability factors (i.e., sensitivity and adaptability). Using the multiple criteria decision-making (MCDM) method approach, suitable criteria, their optimal weights and the risk factors were determined. Modelling, remote sensing, and geographic information system (GIS) methods were used simultaneously for data collection, evaluation, and mapping. A case study was conducted in the coastal area of southeastern Vietnam, which comprises 27 subregions. These were classified into four environmental incident levels: low, medium, high, and extreme. Their prevalence was 70.37%, 3.70%, 7.41%, and 18.52% in the rainy season, and 74.07%, 7.41%, 7.41%, and 11.11% in the dry season, respectively. Based on analysis results and consultation with managers and experts, pertinent and practical solutions were proposed to reduce the risk of environmental incidents in subregions with high and extreme incident levels. Our results are expected to support policymakers in decision-making related to the sustainable development of the study area and complete the methodology framework for assessing environmental incidents in coastal areas due to multiple hazards.

Roof gardening is popular for increasing green space in cities due to the restricted urban areas. However, when watering plants on a roof garden, one should consider loading capacity of the roof, which may limit water supply to the plants therein. To improve the efficiency in irrigating trees in a roof garden, we evaluated plant water status, represented by midday leaf water potential (ΨL), and leaf gas exchange parameters including stomatal conductance (gs) and net photosynthesis (An) of a tree (Tabebuia argentea, Ta) and a palm (Ptychosperma macarthurii, Pm) species, which dominate the garden. The ΨL mediated responses of gs and An, regulating plant water use and growth, to soil moisture. Results showed that ΨL of Ta significantly varied with changes in soil moisture, being low at low and high soil moisture. Nevertheless, gs of Ta linearly decreased when ΨL increased, suggesting a stronger response of gs to atmospheric demand. In contrast, no significant responses among the study variables were observed in Pm. For both species, An initially increased with gs and saturated after gs reached 200 mmol m-2 s-1, indicating similar stomatal regulation on atmospheric carbon dioxide absorption. The limited space for root growth and the location with surrounded building walls contributed to unconventional response patterns observed in Ta. Nonetheless, our results suggested that Ta was more sensitive to changing environments, especially the atmospheric demand, than Pm. Additionally, Ta should be irrigated during daytime and when atmospheric vapor pressure deficit is less than 2.6 kPa to allow high photosynthesis and evaporative cooling while Pm may be watered less frequently to reduce the roof’s loading and save water. This initial investigation implied that maintaining urban trees using appropriate irrigation that is specific to tree species is the key to maximize benefits from urban trees and optimize urban water use.