This study introduces nitrogen atoms into biomass-derived activated carbon (AC) to enhance its sensitivity to formaldehyde vapor at room temperature. Nitrogen-doped activated carbon (N-AC) derived from coconut shells was successfully prepared by heat treatment with ammonia (NH3) at 800°C. The atomic ratio of nitrogen to carbon in N-AC was approximately 4.1 at.%. AC and N-AC were separately mixed with ethanol and then dropped onto a printed circuit board with Au/Cu electrodes, serving as the sensor substrate. The as-fabricated AC and N-AC sensors were exposed to formaldehyde concentrations ranging from 1 to 100 parts per million (ppm) at room temperature. N-AC sensor demonstrated a sensor response approximately 5- to 6-fold higher than that of the AC sensor. The enhancement of formaldehyde sensitivity is attributed to the increased surface area, porosity, and nitrogen doping of AC. The sensing mechanism can be explained by the charge transfer from formaldehyde molecules to the sensing materials. Nitrogen-doped sites play a crucial role in improving formaldehyde adsorption because of their high binding energy and significant charge transfer, resulting in an enhanced sensor response. This study proposes an effective method involving NH3 heat treatment for biomass-derived AC to improve the surface area, porosity, and nitrogen doping of AC to enhance the sensitivity of formaldehyde detection at room temperature.

The management of solid waste at rural schools is relatively overlooked, given its potential for environmental sustainability. In this study, Eastern Potia National High School, Alfonso Lista, Ifugao, Philippines, was monitored daily for 20 days. Using the Waste Analysis and Characterization Study (WACS) protocol, we assessed the volume, composition, generation rate, and density of waste from the waste sources within the school. The analyses showed that biodegradable waste with a predominantly food waste component was the highest at 71.82%, with the school canteen providing the greatest proportion. Recyclable and residual waste comprised 16.73% and 11.45%, respectively, with no special waste generated. The volume of waste, particularly, increased on special events such as exam days, Valentine’s Day, and parent–teacher conferences, displaying the influence of school events on waste generation. Therefore, school-based interventions such as the implementation of composting, waste segregation, and integrating environmental education within school curricula are recommended. This research supports UN Sustainable Development Goal (SDG) 12 (Responsible Consumption and Production) by providing actionable information regarding context-based and activity-driven waste management in rural educational institutions.

As rising sea levels threaten to render low-lying island states uninhabitable, international law faces an urgent dilemma - whether statehood persists without territory or not. The traditional idea of statehood is called into question if increasing sea levels submerge an entire nation’s landmass. Traditional legal frameworks, anchored in the territorial criteria outlined by the Montevideo Convention, provide no definitive guidance on this unprecedented scenario. This article proposes “climate sovereignty,” a novel theoretical framework designed to address the challenges of climate-induced territorial loss. Climate sovereignty redefines statehood beyond fixed territory, emphasizing the continuity of a people, their governing institutions, and collective identity, even when physical territory is submerged or uninhabitable. By shifting international legal recognition from a land-centric approach to a communitybased framework rooted in self-determination, climate sovereignty offers a legal pathway responsive to the evolving realities of vulnerable states. Through illustrative cases of Tuvalu and Kiribati, this article demonstrates the normative justification and legal viability of recognizing deterritorialized statehood within contemporary international law. Ultimately, this article seeks to advance international law’s response to an unprecedented existential threat, advocating for proactive recognition mechanisms and urging a fundamental reconsideration of sovereignty itself. It argues that, in a climate-altered world, nationhood must not disappear alongside territory.

This study investigates the dynamics of indoor volatile organic compounds (VOCs), including formaldehyde, xylene, and toluene, within a newly constructed smart urban building in Bangkok, Thailand. It aims to identify key determinants of air quality and to support datadriven strategies for healthier indoor environments. A total of 120 indoor air samples were collected from multiple zones and timeframes, considering building usage patterns, air conditioning operation, and environmental factors such as temperature, humidity, and air velocity. Statistical analyses revealed that air velocity and usage time significantly influenced VOC concentrations, while the time period was a critical factor for formaldehyde levels. Toluene concentrations exceeded the ACGIH guideline (20 ppm) in 13% of samples, and formaldehyde levels surpassed NIOSH thresholds in all samples, indicating potential exposure risks. Higher ventilation rates were linked to reduced pollutant accumulation, particularly during peak occupancy. Strong correlations between toluene and xylene also indicated shared emission sources. Although most values remained within regulatory limits, some exceeded health-based guidelines. These findings highlight the complex interactions among building operations, environmental conditions, and chemical exposure, and suggest targeted ventilation scheduling, particularly early-morning activation, to reduce VOC peaks. The study provides a practical framework for designing adaptive ventilation systems and developing guidelines to improve indoor air quality in new buildings. Insights from this research can inform future policy, urban planning, and smart building design aimed at reducing health risks and enhancing environmental resilience.

Increasing environmental concerns over plastic waste and the depletion of non-renewable resources have intensified the search for sustainable alternatives in rubber reinforcement. This review comprehensively investigates the use of recycled polyethylene terephthalate (r-PET) as a green reinforcing agent in rubber compounds, replacing traditional fillers such as carbon black and silica. Experimental studies reveal that incorporating r-PET can improve tensile strength by up to 45%, enhance thermal stability by 20–30°C, and lead to energy savings of approximately 50 MJ.kg-1 compared to virgin PET. Notably, this review is the first to integrate mechanical performance analysis with life cycle assessment (LCA), providing a dual perspective on technical feasibility and environmental impacts. Processing methods, such as mechanical blending, chemical grafting, and surface modification, have been discussed to enhance r-PET compatibility with rubber matrices. Challenges such as poor dispersion, interfacial adhesion, and thermal degradation are critically analyzed, along with mitigation strategies. The findings demonstrate that r-PET not only offers performance and cost advantages but also supports circular economy initiatives by repurposing postconsumer PET waste into high-performance rubber composite. Future research directions are proposed, focusing on hybrid reinforcement systems, compatibility enhancement, and carbon-footprint reduction.

Nowadays, Water pollution is a major global issue brought on by the mixing of effluents from various industries, such as leather, paper, printing, cosmetics, Textile etc., containing metal ions and dyes. This impact causes severe damage to the health of humans, aquatic plants and animals. In view of removing the dyes from the wastewater, several techniques available pose certain drawbacks. To combat such issues, a rapid, cost-effective, eco-friendly, and sludge-less method for removing dye from the effluent using activated Ricinus communis stem as a catalyst in the solar irradiation method is discussed and reported with results. The adsorption studies carried out, followed by degradation of methyl red onto Si-RCS, shows 86% in the presence of natural sunlight, and the optimum dye concentration was 20 ppm at 0.25 g photocatalyst dosage. It depicts that the prepared adsorbent material, Si-RCS, can be used as an effective adsorbent as well as a photo-catalyst to treat textile effluents. The best fit model was found to be pseudo-second order based on the R2 value. Among the isotherm models studied, it was found that Langmuir is the best fit model.

Global weather patterns are greatly impacted by climate change, making droughts more frequent and severe, especially in regions with limited adaptation capacity. This review evaluates the strengths and limitations of widely used drought indices in the context of climate change. Our analysis identifies the Standardized Precipitation Evapotranspiration Index (SPEI) and the Normalized Difference Vegetation Index (NDVI) as the most robust tools for monitoring drought under current and projected climate scenarios, with CMIP6 models indicating increased drought risk for vulnerable regions such as South Asia. The integration of remote sensing and artificial intelligence enhances the accuracy and adaptability of drought monitoring. The findings highlight the need for region-specific frameworks and actionable recommendations for researchers, policymakers, and technologists to improve drought resilience and management strategies.

Assessment of groundwater quality is becoming essential for effective resource management. In this study, we conducted a seasonal assessment of groundwater quality, hydrogeochemical processes, and statistical analyses in the city of Moundou. A total of 62 groundwater samples were taken in the 27 districts of the city, in August 2022 (rainy season) and May 2023 (dry season), respectively. From a geochemical point of view, the results highlighted two dominant geochemical facies in both the dry and wet seasons: the calcium-magnesium bicarbonate facies (Ca-Mg-HCO₃) and the sodium-potassium bicarbonate facies (Na-K-HCO₃). The multivariate analysis showed that the mineralisation of gypsum (CaSO4 · 2H2O), CaCl2 salts, silicates, carbonates and the decomposition of organic matter are the main processes affecting the quality of Moundou’s water. The physico-chemical results show that of the parameters monitored, only pH, iron and ammonium do not comply with the WHO standard, and almost 89% of the sites sampled are considered acceptable according to QWI values. Only the sites in the north-east of the city showed poor water quality during the rainy season. On the whole, this water is of better quality for irrigation.

Marine endophytic bacteria are a promising source of bioactive compounds with diverse applications. This study investigated the multifunctional properties of Bacillus aerius PMRU2.8, isolated from the marine red alga Gracilaria sp. collected from the coastal region of Tamil Nadu, India. The bacterium demonstrated significant antimicrobial activity against multiple human pathogens, with its ethyl acetate extract containing bioactive compounds, including indoles and ketones. Molecular docking analysis revealed potential binding mechanisms of the compounds to bacterial proteins. Additionally, B. aerius efficiently synthesized silver nanoparticles (AgNPs) with enhanced antimicrobial efficacy compared with the crude extract. The bacterium also exhibited remarkable bioremediation capability, decolorizing up to 92.5% of the Direct Blue 6 azo dye within 48 h. Cytotoxicity assays confirmed the potential therapeutic applications of both the extract and the biosynthesized AgNPs. These findings highlight B. aerius as a valuable resource for pharmaceutical development, nanobiotechnology, and environmental remediation.

Biofuel pellet materials are a key renewable alternative to fossil fuels. Evaluating biomass quality is essential for both operational efficiency and environmental impact. This study aimed to produce and characterize biofuel pellets made from rice husks and straw. The pellets were analyzed using ASTM methods and compared against the ISO 17225-6 standard. The results indicated a low moisture content (2.53 ± 0.04 %) and a relatively high ash content (11.96 ± 0.05%). Thermally, the net calorific value was 3,951 ± 7.21 Cal/g. In terms of elemental composition, nitrogen (0.29 ± 0.02%), sulfur (0.15 ± 0.02%), and chlorine (0.34 ± 0.04%) contents were in line with the ISO 17225-6 standard. Additionally, the pellets made from both biomass met durability, length, and diameter specifications. The results indicate that mixing these rice-based biomass improves pellet quality and combustion performance. Lastly, this research supports SDG 7 (ensuring access to affordable, reliable, sustainable, and modern energy for all), SDG 12.2 (promoting the sustainable management and efficient utilization of natural resources), and SDG 12.5 (minimizing waste generation through prevention, reduction, recycling, and reuse).