Practical guidance for selecting plant-substrate combinations in constructed wetlands treating polluted urban waters is limited. This study employed a simulated pollution experiment to assess the purification capacity and net contribution of total nitrogen (TN), total phosphorus (TP), ammonia (NH₄⁺), and chemical oxygen demand (COD) in polluted waters using five commonly used aquatic plants in Beijing, namely Phragmites australis, Typha orientalis, Iris pseudacorus, Scirpus validus, Lythrum salicaria, combined with five substrates including crushed stone, gravel, volcanic rock, ceramic granule, and zeolite. The results showed that: (1) The 25 plant-substrate combined systems effectively removed pollutants, with average removal efficiencies of TN, TP, NH₄⁺ and COD exceeding 63, 21, 79 and 82
Since 2007, annual blooms of the green macroalga Enteromorpha prolifera have occurred in China’s coastal waters, posing serious threats to local aquaculture and ecological environment. Composting is an ideal way for managing E. prolifera waste. This study explored how attapulgite (AT) and biochar (BC) added individually or combinedly (AT-BC) affected ammonia (NH3) and nitrous oxide (N2O) emissions, maturity and bacterial community during co-composting of E. prolifera and agricultural waste. Compared with the control and single AT or BC, AT-BC improved compost maturity and shortened composting cycle (from 60 to 15 d). AT-BC showed the lowest cumulative emissions of NH3 and N2O, which were 35 and 20
The use of wastewater-influenced surface waters for agricultural irrigation is common in many regions, yet its implications for soil geochemistry remain insufficiently characterized, particularly in Andean micro-watersheds. This study evaluates the occurrence and distribution of potentially toxic elements (PTEs) in agricultural soils irrigated with wastewater-influenced surface waters within an Andean micro-watershed in Peru. Seven composite soil samples representing individual cultivated plots were analyzed for trace element concentrations using inductively coupled plasma mass spectrometry, together with physicochemical and mineralogical characterization. Hydrochemical data were used to characterize irrigation water quality within the micro-watershed context. Contamination factor (CF) and geoaccumulation index (Igeo) were applied to assess relative enrichment with respect to reference background values. All measured PTE concentrations were below the Peruvian Environmental Quality Standards and the World Health Organization and Food and Agriculture Organization guideline values. However, arsenic and cadmium exhibited the highest relative enrichment among the analyzed elements, with CF values of 2.89 and 1.89, respectively, and positive Igeo values indicative of unpolluted to moderately polluted conditions. In contrast, hydrochemical analyses showed stable Ca–HCO₃ water facies and low trace element concentrations at the time of sampling. The results indicate that regulatory compliance does not necessarily imply uniform geochemical behavior among elements at the plot scale. These findings highlight the value of enrichment-based indicators for identifying subtle deviations from background conditions that may not be evident from regulatory threshold assessments alone.
Phytoremediation is a nature-based solution that utilizes plants’ ability to reduce, remove, or detoxify environmental contaminants. This study performed a comprehensive bibliometric analysis using the Scopus database from 2005 to 2025 to evaluate the 20-yr research progress and development of phytoremediation technology in Thailand. The most influential authors, institutions, and research hotspots in this field were identified. Over time, the research focus has developed from plant-centric and single contaminant-based studies to more integrated phytoremediation technologies, such as amendment-assisted and microbial-assisted phytoremediation in co-contaminated environments. However, field-scale implementation remains constrained due to limited community engagement and systemic policy integration. To transition this technology from the lab to the field, future efforts must focus on fostering public engagement and designing evidence-based environmental policies.
The present study explores the transformation of waste packaging plastics high-density polyethylene (HDPE), polypropylene (PP), and polystyrene into combustible condensates through slow pyrolysis at low temperatures, using a custom-built reactor inspired by the Blest machine model. To characterize their structural properties, the original plastic materials, their pyrolysis derivatives, and three conventional liquid fossil fuels were examined using advanced techniques, including 1H relaxometry, double quantum nuclear magnetic resonance, and Fourier Transform Infrared spectroscopy. The resulting condensate oils, collected unfiltered, exhibited clear amber shades and demonstrated partially Newtonian fluid behavior. A comparative analysis of their calorific values with traditional fossil fuels revealed that HDPE and PS-derived oils possess viable fuel properties, although the production process remains costly.
Abstract This study investigated clay adsorbents for benzothiophene sulfone (BTO) removal through oxidative desulfurization. Bentonite-Fe 3+ (BF3), Fe 6+ (BF6), activated clay-Fe 3+ (ACF3), and Fe 6+ (ACF6) were synthesized via impregnation of raw bentonite (BR) and raw activated clay (ACR) with Fe 3+ and Fe 6+ ions. Fourier transform infrared analysis identified the functional groups before and after impregnation and sulfur adsorption. The proposed mechanism involves covalent bonding between double-bonded oxygen of the sulfone and the oxygen of the hydroxyl group on the surface of the adsorbent. Scanning electron microscopy was then used to observe the adsorbent morphology. This showed that iron impregnation resulted in the conglomeration of particles, lowering the available surface area. This was confirmed with the Brunauer, Emmett, and Teller analysis as the specific surface area decreased in the following order: raw > Fe 3+ > Fe 6 . Experiments were done in batch with model oil using toluene and BTO, where adsorption time, temperature, and adsorbent dosage were varied to test their effect on BTO removal. Calculations using kinetic models showed that clay adsorbent and BTO systems closely follow the pseudo-second order model, indicating that the reaction rate is limited by the chemisorption rate. Equilibrium isotherms showed that BTO onto BF3 and ACR systems align with the Freundlich model, which suggests that BTO is adsorbed heterogeneously. The BTO and BR, BF6, ACF3, and ACF6 systems closely follow the Dubinin-Radushkevich model, suggesting that sulfones are removed through micropore filling. Thermodynamic studies showed that the clay adsorbent and BTO systems are endothermic and non-spontaneous.
This study reviews the various micro- and nano-plastic (MNP) pollution, which demands immediate mitigation strategies in aquatic ecosystems to ensure an effective, scalable, and sustainable solution. The focus is summarising the physical, chemical, and biological processes to remediate MNP contamination. Physical techniques such as adsorption, flotation, and filtration are also considered representative strategies. Pollutants like biochar and carbon nanotubes can be removed by adsorption in plants. However, there is a risk of secondary pollution from this. Advanced filtration methods, such as sand filtration and membrane bioreactor, can achieve very high removal efficiency, but problems with membrane fouling limit scalability. Flotation holds tremendous potential if the right conditions are implemented. It also includes the chemical degradation methods (polar media like hydrogen peroxide and advanced oxidation processes (AOPs) and thermal degradation. Some AOPs rely on reactive species to degrade plastics, but they typically follow an energy-intensive route, whereas thermal degradation can decompose plastics with its own environmental cost. A molecular approach involving biological remediation, involving microbial and enzymatic degradation, is perceived as an environmentally friendly solution. Organisms with promising plastic-degrading abilities include Pseudomonas aeruginosa and Bacillus cereus, genetically engineered microorganisms, and fungal treatments. Moreover, the degradation of MNPs plays a substantial role in microbial biofilms. Nanotechnology is a potential supplement to MNP remediation processes, especially engineered nanoparticles. However, the study highlights the need for further research to optimise these methods, improve scalability, and ensure environmental safety, recommending a multi-faceted approach to ensure the effective and sustainable mitigation of MNP pollution.
Thailand generates approximately 114 Mt of agricultural waste annually from rice, maize, and sugarcane fields, with open burning contributing to severe economic, health, and environmental crises. This study assesses the transition from open burning to sustainable residue management—ploughing, composting, and biomass energy generation—through cost–benefit analysis and Life Cycle Assessment of greenhouse gas emissions. Data were collected using Geographic Information System, surveys, focus groups, and interviews. The findings indicate that all alternatives are economically viable, with composting yielding the biggest profitability for rice (Net Present Value (NPV) = 250,607 million Baht (1 Baht approx. = 0.03 USD), Benefit–Cost Ratio (BCR) = 5.22) and maize (NPV = 192,964 million Baht, BCR = 3.34). In comparison, biomass energy is the most cost-effective option for sugarcane (NPV = 681,936 million Baht, BCR = 4.18). To mitigate agricultural burning and pollution, policies should promote organic fertilizer production and provide sustained financial support for small-scale farmers, facilitating a large-scale transition toward sustainable waste management.
Effective waste classification is a key challenge in modern environmental management and recycling systems. Despite the success of deep learning models in visual recognition, their high computational cost often limits practical deployment. This study aims to develop an efficient and accurate waste classification framework by integrating transfer learning with machine learning techniques. Specifically, a pre-trained VGG16 network is utilized for feature extraction, and a K-Nearest Neighbors classifier is applied for final classification. The approach is evaluated on a dataset of high-resolution waste images categorized into nine classes. Experimental results demonstrate an outstanding 99.9
Increasing chicken manure generation from intensive poultry farming has created the need for sustainable valorization strategies. This study evaluated the potential of chicken manure-derived biochar (CMB), produced through a large-scale pyrolysis process, as a soil amendment agent for improving soil quality and mitigating environmental pollution. Notably, the effects of CMB application on the soil physicochemical properties, microbial enzyme activities, and heavy metal adsorption capacity were comprehensively investigated. The results of the study show that the incorporation of 3
This study evaluates the sustainability of biodiesel production from selected feedstocks, comprising grease trap waste (GTW), animal tallow waste, and waste cooking oil, by utilizing a life cycle assessment method. The process focuses on converting these non-edible waste oils into biodiesel through advanced transesterification methods, highlighting the potential of renewable resources to enrich energy security and support sustainable development in Pakistan. The process involves various stages of feedstock utilization, including collection, transportation, pretreatment, transesterification, purification, blending, and distribution, resulting in different inventories for each of the three selected feedstocks. Environmental impacts were assessed using a life cycle impact assessment framework, which utilized the ReCiPe methodology for each feedstock, encompassing a total of 10 selected midpoint and endpoint categories. Among the three feedstocks, GTW exhibits the highest environmental impacts, with midpoint results indicating significant contributions to climate change (37.5 kg CO2 eq.) and fossil depletion (9.03 kg oil eq.). In contrast, a solar scenario showed global warming potential as 22.5 kg CO₂ eq. and fossil depletion of 5.41 kg oil eq. kg− 1 GTW feedstock. Moreover, the economic assessment revealed the feasibility of biodiesel production, achieving a daily revenue of USD 7,500 in a single 8-h shift, with an annual revenue of USD 2,737,500. Economic indicators, including payback period and net present value, were also evaluated. The payback period is calculated to be 1.05 years, and the net present value is evaluated at USD 2.85 million, indicating the profit of the production system. Remarkably, the top key environmental emissions in external cost analysis related to the cost of processed feedstock were also calculated as dominated by CO₂ and NOx emissions. Hence, the production of biodiesel not only addresses waste management challenges but also contributes to waste-to-energy conversion and renewable energy generation, aligning with public health goals and sustainable development. The findings highlight the potential of biodiesel production as a strategic solution, and it can be reformed with circular economic principles to achieve global sustainability while delivering stronger economic rates of return. Furthermore, the findings of this study are directly linked to the numerous United Nations Sustainable Development Goals (SDG), including SDG 7, SDG 9, SDG 12, and SDG 13, by promoting cleaner energy technologies, enhancing innovation and infrastructure in the renewable energy sector, employing circular economies, and minimizing greenhouse gas emissions, respectively.
Dichloroacetonitrile (DCAN), a nitrogenous disinfection byproduct, is the most frequently detected haloacetonitrile species in drinking water. This study evaluates the degradation of DCAN using vacuum ultraviolet (VUV)-based advanced oxidation processes (AOPs), compared with VUV alone. VUV-based AOPs were combined with common oxidizing agents—H2O2, Cl2, and persulfate (PS)—to generate reactive radical species such as HO•, Cl•, and SO4•– for enhancing DCAN removal. The effects of oxidant dosage, humic acid, and inorganic constituents in water were systematically examined. Results showed that first-order rate constants for DCAN degradation using VUV/PS (20–100 mg PS L–1) were higher than those observed with VUV/Cl2 (2 mg Cl2 L–1), VUV, and VUV/H2O2. Increasing PS doses enhanced DCAN removal rates, while increasing Cl2 and H2O2 doses (10–100 mg L–1) either reduced or had minimal effect on degradation efficiency. The highest removal rate constant (0.37 min–1) and efficiency (100
The petrochemical industry is a cornerstone of Taiwan’s economy, yet its potential impacts on surrounding communities have drawn sustained public scrutiny. To characterize hazardous air pollutants (HAPs) in the ambient atmosphere around the Linyuan Petrochemical Industrial Park, we deployed nine monitoring stations in the surrounding area. Using a combination of continuous automatic instruments and manual sampling, we measured specific pollutant classes, including 54 species of photochemical volatile organic compounds (VOCs) precursors, 52 HAPs, aldehydes, sulfides, 7 heavy metals, dioxins, and other atmospheric contaminants. Data were processed in accordance with procedures described in the U.S. EPA National Monitoring Programs annual report, and concentration patterns from 2019 to 2024 were analyzed for six key stations adjacent to the industrial park. We further compared observed levels with international reference values to identify priority pollutants and potential health implications. Annual average concentrations of heavy metals at all stations remained consistently below international reference values, suggesting that emissions from the petrochemical complex are unlikely to drive metal-related health risks for nearby residents. By contrast, annual average concentrations of benzene and formaldehyde at most stations exceeded international reference values, indicating potential health concerns associated with these hazardous VOCs. In addition, elevated concentrations of 1,2-dichloroethane, vinyl chloride, and acrylonitrile were observed at one station (Station A), warranting targeted investigation. Overall, benzene, formaldehyde, 1,2-dichloroethane, and vinyl chloride emerged as priority pollutants in the ambient environment surrounding the complex, with localized hotspots (e.g., Station A) requiring focused assessment and the implementation of site-specific mitigation measures.
The accelerating rise in atmospheric carbon dioxide (CO2) concentration poses a critical challenge for achieving China’s dual carbon goals. To uncover the complex mechanisms driving this trend, this study integrates high-resolution satellite observations with socioeconomic, ecological, and meteorological datasets to analyze the spatiotemporal dynamics of column-averaged atmospheric CO2 (XCO2) across China from 2015 to 2020. Using an ensemble machine learning framework centered on the Random Forest (RF) model, this research moves beyond traditional linear regression to detect nonlinear thresholds, variable interactions, and spatial heterogeneity in the determinants of XCO2. Spatiotemporal analysis reveals a steady national increase in XCO2, accompanied by pronounced seasonal and regional fluctuations. The RF-based feature importance and partial dependence analyses expose several critical nonlinear relationships: XCO2 increases sharply with Open Source Data Inventory of Anthropogenic Carbon Dioxide emissions up to 500,000 kg m− 2 h− 1; declines by 0.8 ppm for every 0.1 increase in Normalized Difference Vegetation Index beyond the 0.5 threshold; shifts from a negative to positive temperature correlation around 25 °C; and follows a U-shaped pattern with relative humidity, decreasing below 72
Abstract Water can be severely contaminated by the reckless dumping of industrial effluents, which contain organic pollutants such as pharmaceuticals, phenolic compounds, and dyes, with cascading effects on human health and the ecosystem. Remarkably, photocatalysis is a rapidly expanding method for treating a wide range of organic pollutants. Here, the photocatalytic activity of Ag-doped α-Fe2O3 (metal-doped oxide nanocomposites) is compared with that of monolithic catalysts (substrate-based materials), offering an economical, environmentally friendly, efficient, and low-power/sunlight-driven process. The results revealed that the substrate-based catalysts could improve the photodegradation efficiency of as-fabricated nanocomposite photocatalysts. The electrochemical property of 3% Ag: α-Fe2O3/Ni/Graphene Foam (GF) (optimized catalyst) exhibits smaller over potential (Oxygen Evolution Reaction (OER): 84 mV and Hydrogen Evolution Reaction (HER): 214 mV) with remarkably minimum resistance (OER: 1.3 Ω and HER: 33 Ω) and high Tafel slope due to bubbles formation (OER: 43 mV dec− 1 and HER: 170 mV dec− 1) to achieve 10 mA cm− 2 of current density, indicating efficient charge transfer activity which correlate with the photodegradation performance of photocatalyst. The highest degradation rate against selected organic pollutants was also achieved by optimal 3% silver doping: ciprofloxacin (62% within 70 min) > Methyl Orange (59% within 90 min) > 2,4-dinitrophenol (DNP with 39% within 120 min), representing more complex and stable chemical structures of Methyl Orange (-N = N-) and 2,4-DNP (-NO2 groups). The degradation process followed a pseudo-first-order kinetic model (R2 values close to 1) beyond the optimal doping level. Photocatalytic and electrochemical activity decreased due to e−-h+ recombination, decreased surface area, and reduced availability of reactive species. Additionally, the reusability of the optimized monolithic catalyst showed only 2.4, 3.8, and 4.6% decreases in ciprofloxacin, Methyl Orange, and 2,4-DNP, respectively, thus confirming its stability and sustainability as a promising candidate for organic industrial wastewater treatment.
Abstract This manuscript introduces a novel approach integrating smart technologies and sustainable aviation fuel (SAF) production within solid waste management hierarchy to address waste accumulation and aviation emissions. The study demonstrates that approximately 960 Mt of municipal solid waste are available globally for biofuel conversion, with potential to produce 115 MT of SAF through gas/Fischer-Tropsch pathways. Our analysis reveals SAF production from waste reduces net greenhouse gas emissions by 27–87% compared to conventional jet fuel, with 1000 kg of waste converted yielding a 380 kg CO₂ reduction. The research establishes a revised environmental hierarchy prioritizing composting for biodegradable waste, followed by SAF production for non-compostable materials, with incineration as a last resort, addressing significant air pollutants and emissions from traditional incineration. The integration of smart technologies (digital and automated tools like Internet of Things, artificial intelligence, sensors, and data analytics that improve efficiency, traceability, and decision-making in waste management) boosts operational performance and facilitates waste-to-fuel conversion. Despite environmental benefits, economic challenges persist, with SAF production costs 2–8 times higher than fossil jet fuel. However, the global SAF market is projected to grow at 57.5% Compound Annual Growth Rate from USD 576 million (2022) to USD 15.7 billion (2030), improving viability through policy support and economies of scale. This integrated model addresses dual crises of waste management and aviation decarbonization while supporting the transition toward circular economies and climate-resilient infrastructure.
Abstract Traditional methods for N, N-dimethylacetamide (DMAC) degradation often generate excessive sludge and have high operational costs. This study proposes an advanced oxidation process (AOP) based on manganese- and ruthenium-loaded activated carbon (AC-MnRu) combined with ozone to overcome these challenges. Characterization using scanning electron microscopy, high resolution transmission electron microscopy, X-ray adsorption near-edge structure, X-ray photoelectron spectroscopy, Raman spectrometer and x-ray diffraction confirmed the structural and chemical properties of AC-MnRu. Under optimal conditions (catalyst dosage: 20 g L-1, pH 10, ozone flow rate: 2.8 g h-1, 80 °C, DMAC initial concentration of 1800 mg L-1), the catalyst achieved over 95% DMAC degradation and 98% chemical oxygen demand (COD) removal during the initial cycle. This significantly outperformed AC oxidation (25% COD and 35% DMAC removal) and ozone oxidation alone (14% COD and 30% DMAC removal), with no sludge formation. Furthermore, long-term stability tests demonstrated that the AC-MnRu/O₃ system maintained 89% DMAC removal after six reuse cycles, confirming sustained catalytic activity. Radical scavenging experiments identified hydroxyl radicals, superoxide radicals, and singlet oxygen as key reactive species. Additionally, in real wastewater treatment, the AC-MnRu/O₃ system achieved 80% DMAC removal and 78% COD removal after six cycles (initial COD: 1542 mg L-1, DMAC: 770 mg L-1), demonstrating its potential for industrial applications. These results highlight the potential of the AC-MnRu/O₃ system as a robust and sustainable treatment strategy for high-strength industrial wastewater.
Abstract This study evaluates engine performance and emission characteristics of diesel/biodiesel/HVO blends (biodiesel: 0–30% vol., HVO: 10% vol.). Results demonstrate significant reductions: PM2.5 (12.5–43.9%), CO (8.01–24.5%), SO₂ (7.69–25.9%), and NOx (3.33% reduction via HVO addition). Metal emissions (Na/Fe/Ca/Al > 80% of total detected metals) decreased by 24.3–26.8%, while brake-specific fuel consumption (BSFC) improved by 2.21%. Electron paramagnetic resonance (EPR) spectroscopy revealed consistent PM2.5 microstructural properties across blends (g-factor: 2.0033–2.0035), though radical concentrations (3.0 × 1018-7.4 × 1018 spins/g) exceeded ambient levels by 10-fold. Raman analysis confirmed invariant carbon nanostructures (D/G band ratio: 0.910–0.943), indicating fuel composition primarily modulates emission quantity rather than particulate quality. These findings establish HVO-biodiesel blends as effective fossil diesel alternatives, warranting further research on environmentally persistent free radicals (EPFRs).
Abstract Biochar (BC) is an emerging material produced by the pyrolysis of biomass and has been used for various environmental applications. In this study, BC prepared from rice husk waste was employed to activate peroxymonosulfate (PMS) and peroxydisulfate (PDS) for the removal of pentachlorophenol (PCP) in groundwater. Specifically, the removal kinetics was investigated, the influences of groundwater matrix were examined, and the removal mechanism was explored. The results showed that the prepared BC could only activate PMS to degrade PCP while PDS could not be activated by the BC. The rate of PCP removal increased with the increasing PMS concentration and BC loading, in which more than 85% removal can be achieved in 90 min. Radical quenching experiments and electron paramagnetic resonance studies indicated that singlet oxygen (1O2) was responsible for the degradation of PCP in the PMS system. The presence of HCO3 − and humic acid appeared to inhibit the removal of PCP under groundwater conditions. Reusability tests showed that the performance of PCP removal decreased after four cycles but calcination regeneration at 150 °C for 30 min was effective to recover the PMS activation capacity of BC.
The shrink-swell behaviour of expansive soils can lead to a range of structural problems, including foundation damage, cracking, and instability. Microplastic contamination in expansive soils is an emerging environmental concern with potential implications for soil behavior and structural stability. Alterations in soil properties, hydraulic conductivity, and shrink-swell behavior due to microplastics could lead to unpredictable soil movement, compromised soil stability, and increased risk of structural damage. The primary objective of the present paper is to review previous research using geopolymer-based stabilization techniques for expansive soils contaminated with microplastics. A detailed bibliometric analysis was performed using Scopus databases to examine global research trends, publication patterns, and significant contributions in this area. The review revealed more than 350 papers on geopolymer-based soil stabilization, with a remarkable rise since 2017, indicating a growing concern for sustainable soil stabilization. Geopolymer-treated soils exhibit significant improvement in Unconfined compressive strength, California bearing ratio and shrink-swell behaviour resistance, and hence they can be considered as a potential alternative to traditional stabilizers. The effectiveness of geopolymer stabilization is influenced by various factors, such as the type of precursor materials used (e.g., fly ash, metakaolin, slag), the concentration of alkali activator, curing condition and ratio of sodium silicate to sodium hydroxide. It further discusses the rising problem of microplastic contamination in soils, sources, environmental impacts, and its implications on soil behaviour. Microplastics substantially affect geotechnical behaviour through the increased hydraulic conductivity, decreased shear strength, and decreased capacity to hold water. The research emphasized an urgent need for optimized formulations of geopolymers that add value by providing improved soil stabilization, as well as a sustainable remediation method to enhance the soil contaminated with microplastics.
