Search Results (208)

The removal of cationic dyes from industrial wastewater presents a significant environmental challenge. This research examines the effectiveness of functionalized cellulose-based silica aerogels as sustainable adsorbents for methylene blue (MB) dye. This research provides a systematic comparative study on the effectiveness of four distinct functionalization strategies, carboxylate (CCNC), double carboxylate (DCCNC), carboxymethyl (CMC), and thiol-modification, applied to cellulose-based silica aerogels as sustainable adsorbents for methylene blue (MB) dye. Cellulose nanocrystals (CNCs) were extracted from sugarcane bagasse waste and subsequently functionalized into carboxylate (CCNC), double carboxylate (DCCNC), carboxymethyl (CMC), and thiol-modified variants. The materials were later integrated into a silica matrix, resulting in the formation of porous aerogel nanocomposites. The materials underwent thorough characterization through FTIR, XRD, SEM, TGA, and BET analyses, validating successful functionalization and the development of mesoporous structures. Batch adsorption tests demonstrated that the CMC-silica aerogel exhibited superior performance, attaining a maximum adsorption capacity of 197 mg/g and complete removal efficiency under ideal circumstances (pH 10, 25 °C, 60 min). The adsorption process is accurately characterized by the Langmuir isotherm and pseudo-second-order kinetic models, signifying monolayer adsorption and chemisorption as the rate-limiting step. The thermodynamic parameters indicate that the adsorption process is exothermic and spontaneous. The CMC-silica aerogel exhibited significant reusability, maintaining over 90% efficiency after six consecutive cycles. The findings illustrate the efficacy of functionalized cellulose–silica aerogels, especially the CMC form, as effective, environmentally sustainable, and reusable adsorbents for the treatment of dye-polluted water. Full article

Emerging contaminants such as per- and polyfluoroalkyl substances (PFASs) pose significant challenges for conventional wastewater treatment technologies. Non-thermal plasma (NTP) has gained attention as a promising advanced oxidation process capable of degrading persistent pollutants via hydrated electrons and reactive oxygen/nitrogen species under ambient conditions. This review summarizes recent progress in the application and scale-up of NTP for water treatment, with a focus on reactor configurations, degradation mechanisms, and energy efficiency. Key plasma reactor types—including dielectric barrier discharge, corona discharge, plasma jets, and gliding arc discharge—are evaluated for their suitability in large-scale applications. Pilot-scale studies addressing pharmaceuticals, dyes, and PFASs are reviewed to assess scalability, cost, and operational viability. Although NTP systems consistently achieve >80% contaminant removal, optimizing energy use and maintaining performance across complex water matrices remain critical challenges. Hybrid systems integrating NTP with ozonation, ultrafiltration, or cavitation show potential to improve treatment efficacy and reduce energy demands. Future research priorities include reactor design optimization, contaminant-specific plasma tuning, and technoeconomic analysis to support the translation of NTP technologies from lab-scale innovation to field-scale implementation. Full article

Microplastics, pervasive environmental pollutants with significant health risks, present formidable challenges in wastewater treatment due to their persistence and resistance to conventional removal methods. This study investigates the efficacy of hybrid ceramic membrane filtration for the systematic removal of micro- and nanoplastics from wastewater, while evaluating the role of anaerobic digestion as a pretreatment to enhance membrane performance. This study systematically assesses the performance of the 1.4 μm pore-sized flat sheet ceramic membrane and the 1 kDa pore-sized tubular ceramic membrane, respectively, for microplastic and nanoplastic removal in wastewater. Also, the effect of anaerobic digestion was assessed in microplastic separation and quantification. Anaerobic digestion reduced suspended solids by 57–67%. The average microplastic concentration was ~1782 MP L⁻¹. However, anaerobic digestion reduced the average concentration to ~913 MP L⁻¹. The opposite trend was observed in nanoplastic concentrations, which were ~4268 and ~10,066 NP L⁻¹, respectively, for the samples without and with anaerobic digestion. The ceramic membrane flux decreased from ~106.5 to ~25 L m⁻² h⁻¹ at a flow rate of 0.4 L min⁻¹ during the collection of 2 L of filtrate. However, anaerobic digestion improved the flux approximately 3 times. The tubular ceramic membrane flux was ~6.1 L m⁻² h⁻¹ at a flow rate of 2.0 L min⁻¹, which was reduced by 50% after the ceramic membrane treatment. By overcoming the limitations of conventional microplastic removal methods, such as the inefficiency of residual chemicals or byproducts, hybrid ceramic membrane filtration is a viable option for a scalable, efficient, and sustainable method in controlling microplastic and nanoplastic pollution. Full article

The insufficient availability of safe water has emerged as a prevalent issue severely impacting public health in developing nations. Moreover, studies reporting the efficacy of treatment plants (TPs)—specifically Phragmites karka and Typha latifolia—in removing toxic elements in aquaculture wastewater are scanty. Therefore, this study is aimed at investigating the effects of hydraulic retention time (HRT), seasonal variations, and TPs on the removal efficiency of pollutants from a vertical subsurface flow constructed wetland (VSSF-CW) in Nigeria. The experiments spanned three seasons (November–December–January—NDJ; March–April–May—MAM; and July–August–September—JAS) of the year, with samples collected from the CW at 7 day intervals for analysis. The aquaculture wastewater was analyzed in the laboratory to determine its chemical and toxic compositions before and after the introduction of treatment plants. Three-way ANOVA was used to analyze the main and interactive effects between HRT, seasons, and TPs on the physicochemical properties of the CW’s effluents. The removal efficiency was determined to evaluate the performance of the constructed wetland in comparison to the treatment plants. Results showed that these constructed wetlands effectively removed contaminants, with significant differences (p < 0.05) mostly observed in the effects of treatment plant types and seasons on the chemical and heavy metal concentrations. This was further confirmed by the main effects of HRT, seasons, and treatment plant choice, which significantly (p < 0.05) influenced treatment efficiency. Removal efficiencies increased with longer HRTs, reaching peak removal efficiencies of approximately 69, 67, and 61% for Na, K, and Ca, respectively. The BOD and COD reached 85 and 90% removal efficiency, while removal efficiency of 100% was achieved for most heavy metals at 21 day retention time. In summary, the study found that TPs (Phragmites karka and Typha latifolia), HRT, and seasonal variation are important for treating integrated poultry and aquaculture wastewater in a VSSF CWs. Full article

High-molecular-weight polycyclic aromatic hydrocarbons (PAHs), such as pyrene, are persistent environmental pollutants that threaten soil health and agricultural productivity due to their resistance to degradation. This study evaluated the efficacy of domesticated bacteria isolated from contaminated farmland soil and activated sludge, used alone and in combination with corn (Zea mays L.), to remove pyrene from soil, enhance plant growth, improve tolerance, and ensure crop safety. Six bacterial strains were isolated: three from polluted farmland soil (WB1, WB2, and WF2) and three from activated sludge (WNB, WNC, and WH2). High-throughput 16S rRNA amplicon sequencing profiled bacterial communities after 30 days of treatment. Analytical tools, including LEfSe, random forest, and ZiPi analyses, identified biomarkers and core bacteria associated with pyrene degradation, assessing their correlations with plant growth, tolerance, and pyrene accumulation in corn straw. Bacteria from activated sludge (WNB, WNC, and WH2) outperformed farmland soil-derived strains and the inoculant strain ETN19, with WH2 and WNC achieving 65.06% and 87.69% pyrene degradation by days 15 and 30, respectively. The corn–bacteria consortium achieved up to 97% degradation. Activated sewage sludge (ASS)-derived bacteria were more effective at degrading pyrene and enhancing microbial activity, while soil-derived bacteria better promoted plant growth and reduced pyrene accumulation in straw. Microbial communities, dominated by Proteobacteria, exhibited high species richness and resilience, contributing to xenobiotic degradation. The corn-domesticated bacteria consortia effectively degraded pyrene, promoted plant growth, and minimized pollutant accumulation in crops. This remediation technology offers a promising strategy for rapid and sustainable bioremediation of agricultural soils contaminated with organic compounds such as PAHs or other complex pollutants, while promoting the development of efficient bacterial communities that enhance crop growth. Full article

Microplastics (MPs), as an emerging persistent contaminant, pose a potential threat to ecosystems and human health. The adsorptive removal of MPs from aqueous environments using magnetic nanoparticles has become a particularly promising remediation technology. Nevertheless, there remain significant knowledge gaps regarding its adsorption mechanism, especially how the key physical properties of magnetic nanoparticles regulate their adsorption behavior towards MPs. This study first investigated the relationship between the particle size of Fe₃O₄ nanoparticles and their adsorption efficacy for MPs. The results demonstrated a non-monotonic, size-dependent adsorption of MPs by Fe₃O₄ nanoparticles, with the adsorption efficiency and capacity following the order: 300 nm > 15 nm > 100 nm. This non-linear relationship suggested that factors other than specific surface area (which would favor smaller particles) are significantly influencing the adsorption process. Isotherm analysis indicated that the adsorption is not an ideal monolayer coverage process. Kinetic studies showed that the adsorption process could be better described by the pseudo-second-order model, while intra-particle diffusion played a critical role throughout the adsorption process. Furthermore, the effect of pH on adsorption efficiency was examined, revealing that the optimal performance occurs under neutral to weak acidic conditions, which is consistent with measurements of surface charges of nanoparticles. These findings suggest that the adsorption is not determined by specific surface area but is dominated by electrostatic interactions. The size-dependent adsorption of MPs by Fe₃O₄ nanoparticles provides new insights for the modification of magnetic adsorbents and offers a novel perspective for the sustainable and efficient remediation of environmental MPs pollution. Full article

Per- and polyfluoroalkyl substances (PFAS) are a diverse group of synthetic fluorinated compounds widely used in industrial and consumer products due to their exceptional thermal stability and hydrophobicity. However, these same properties contribute to their environmental persistence, bioaccumulation, and potential adverse health effects, including hepatotoxicity, immunotoxicity, endocrine disruption, and increased cancer risk. Traditional water treatment technologies, such as coagulation, sedimentation, biological degradation, and even advanced membrane processes, have demonstrated limited efficacy in removing PFAS, as they primarily separate or concentrate these compounds rather than degrade them. In response to these limitations, photoassisted processes have emerged as promising alternatives capable of degrading PFAS into less harmful products. These strategies include direct photolysis using UV or VUV irradiation, heterogeneous photocatalysis with materials such as TiO₂ and novel semiconductors, light-activated persulfate oxidation generating sulfate radicals, and photo-Fenton reactions producing highly reactive hydroxyl radicals. Such approaches leverage the generation of reactive species under irradiation to cleave the strong carbon–fluorine bonds characteristic of PFAS. This review provides a comprehensive overview of emerging photoassisted technologies for PFAS removal from water, detailing their fundamental principles, degradation pathways, recent advancements in material development, and integration with hybrid treatment processes. Moreover, it discusses current challenges related to energy efficiency, catalyst deactivation, incomplete mineralization, and scalability, outlining future perspectives for their practical application in sustainable water treatment systems to mitigate PFAS pollution effectively. Full article

Arsenic pollution in potable water is a significant worldwide health concern. This study systematically evaluates current progress in adsorption technology, the most promising restorative approach, to provide a definitive framework for future research and use. The methodology entailed a rigorous evaluation of 91 peer-reviewed studies (2012–2025), classifying adsorbents into three generations: (1) Natural adsorbents (e.g., agricultural/industrial wastes), characterized by cost-effectiveness but limited capacities (0.1–5 mg/g); (2) Engineered materials (e.g., metal oxides, activated alumina), which provide dependable performance (84–97% removal); and (3) Advanced hybrids (e.g., MOFs, polymer composites), demonstrating remarkable capacities (60–300 mg/g). The primary mechanisms of removal are confirmed to be surface complexation, electrostatic interactions, and redox precipitation. Nevertheless, the critical analysis indicates that despite significant laboratory efficacy, substantial obstacles to field implementation persist, including scalability limitations (approximately 15% of materials are evaluated beyond laboratory scale), stability concerns (e.g., structural collapse of MOFs at extreme pH levels), and elevated costs (e.g., MOFs priced at approximately $230/kg compared to $5/kg for alumina). The research indicates that the discipline must transition from only materials innovation to application science. Primary objectives include the development of economical hybrids (about $50/kg), the establishment of uniform WHO testing standards, and the implementation of AI-optimized systems. The primary objective is to attain sustainable solutions costing less than $0.10 per cubic meter that satisfy worldwide deployment standards via multidisciplinary cooperation. Full article

Despite the immense potential in environmental remediation, the translation of magnetic nanomaterials (MNMs) from laboratory innovations to practical, field-scale applications remains hindered by significant technical and environmental challenges. This is particularly evident in soil environments—which are inherently more complex than aquatic systems and have received comparatively less research attention. Beginning with an outline of the fundamental properties that make iron-based MNMs effective as adsorbents and catalysts for heavy metals and organic pollutants, this review systematically examines their core contaminant removal mechanisms. These include adsorption, catalytic degradation (e.g., via Fenton-like reactions), and magnetic recovery. However, the practical implementation of MNMs is constrained by several key limitations, such as particle agglomeration, oxidative instability, and reduced efficacy in multi-pollutant systems. More critically, major uncertainties persist regarding their long-term environmental fate and biocompatibility. In light of these challenges, we propose that future efforts should prioritize the rational design of stable, selective, and intelligent MNMs through advanced surface engineering and interdisciplinary collaboration. Full article

The escalating demand for rural domestic wastewater treatment necessitates environmentally sustainable and cost-effective technologies. This study investigated the enhancement of a micro/nano aeration biofilter (MABF) through electric field coupling (E-MABF), evaluating pollutant removal efficacy and associated bacterial community dynamics. The results showed that the electric field significantly enhanced removal efficiency with respect to total phosphorus (TP), phosphate (PO₄³⁻-P), ammonium nitrogen (NH₄⁺-N), and chemical oxygen demand (COD) (p < 0.05). The TP, PO₄³⁻-P, NH₄⁺-N, and COD removal efficiencies for E-MABF reached 89.79%, 88.69%, 57.29%, and 57.96%, significantly exceeding those of MABF (26.50%,33.41%, 35.49%, and 45.75%). Electric field application markedly altered bacterial diversity and community composition. Core phyla, including Pseudomonadota, Chloroflexota, and Cyanobacteriota, exhibited significant positive correlations with pollutant removal efficiencies, indicating electric field facilitation of functional bacterial enrichment. KEGG pathway analysis suggested that electric field stimulation potentially enhanced metabolic functions, particularly in terpenoid and polyketide metabolism, and xenobiotics biodegradation. The Mantel’s test and structural equation model identified dominant bacterial composition as the primary factor influencing pollutant removal, followed by microenvironmental indicators and bacterial diversity. These findings elucidate the mechanisms underpinning the electric field augmentation of micro/nano aeration biofilter performance and provide a foundation for future research. Full article

In recent years, graphitic carbon nitride (g-C₃N₄) has gained considerable ground in the field of heterogeneous photocatalysis for the abatement of emerging contaminants from aqueous environments. Nonetheless, certain limitations, including a small surface area and a high recombination rate, limit its photocatalytic efficacy. In this study, g-C₃N₄ was synthesized from urea and then underwent thermal exfoliation. A portion of the exfoliated material was subsequently subjected to protonation via acid treatment, and both protonated and non-protonated variants of exfoliated g-C₃N₄ were combined with small amounts of Ti₃C₂T_x MXene. The morphology, chemical structure, and optical properties of the synthesized materials were examined using various characterization techniques. Additionally, their photocatalytic performance was evaluated through laboratory tests using the commonly detected anti-hypertensive drug valsartan as a model pollutant. The degradation kinetics of valsartan revealed that combining 1% Ti₃C₂T_x MXene with exfoliated g-C₃N₄ (both protonated and non-protonated) achieves optimal removal. Notably, the composite material 1%-pCNMX (protonated variant) displayed a 20% higher removal kinetic rate than unmodified exfoliated g-C₃N₄, removing a higher quantity of valsartan within the same time frame. Furthermore, all protonated composites proved more effective in degrading valsartan than their non-protonated counterparts, demonstrating the positive impact of acid treatment. The improved photocatalytic activity was attributed to the successful formation of Schottky junctions between g-C₃N₄ and Ti₃C₂T_x, which reduced the recombination rate of photogenerated charge carriers. Full article

Water pollution has escalated to critical levels in recent years as evident by the multiplicity of contaminants found in potable water sources. A point-source major contributor is the textile industry, which discharges substantial amounts of dye into rivers and lakes. Bacterial cellulose (BC), a renewable and low-cost nanocellulose material, has emerged as a potential solution addressing dye removal from these contaminated waters. Methylene Blue (MB) was selected as a representative dye for our adsorption studies. As a baseline for evaluating efficacy, BC was dried using three different methods: freeze-drying, oven-drying, and room-temperature drying. The adsorptive behavior of these dried BC samples toward MB in an aqueous environment was evaluated. Furthermore, to elucidate the structure–property relationship of dried BC, several characterization techniques were employed. Our studies revealed that freeze-dried BC exhibited the highest initial adsorption rate, while oven-dried BC demonstrated the overall highest adsorption capacity. Moreover, the adsorption data corresponded well with pseudo-second-order and Freundlich isotherm models. This investigation provides a comprehensive understanding of how BC, dried through different methods, performs in the adsorption of MB by establishing a baseline for future research. Full article

Against the challenge of extreme lead (Pb) contamination (>15,000 ppm) in industrial polluted soils, where conventional agents fail to disrupt stable Pb–soil complexes—this study extends our prior cadmium (Cd) remediation research to validate amino acid ionic liquids (AAILs) for highly recalcitrant metals. Fifteen AAILs were screened via batch washing, with [Met][NO₃] (methionine-based) demonstrating the highest Pb removal efficiency. Single-factor optimization revealed that under the conditions of 0.8 mol/L, 6:1 liquid–soil ratio, 60 min, 85.4% Pb was removed from severely contaminated soil by [Met][NO₃]. Kinetic analysis using four common models showed that the second-order kinetic equation provided the best fit, indicating that Pb removal was predominantly driven by chemical reactions such as complexation or ion exchange. After washing, the contents of various Pb species were significantly reduced, thereby mitigating environmental risks. Notably, no substantial changes in soil texture were observed. However, a marked increase in organic matter content was detected, accompanied by decreases in soil pH and mineral element concentrations. Analysis of soil mineral composition, functional groups, and chemical speciation revealed that [Met][NO₃] primarily facilitated Pb removal through ion-exchange and coordination reactions. This study establishes [Met][NO₃] as a green agent with dual efficacy: it achieves high-efficiency remediation of severely Pb-contaminated soil while ensuring environmental sustainability, thus highlighting its potential for practical application. Full article

Urban wastewater is composed of nutrients such as nitrogen and phosphorus, organic matter, heavy metals, pathogens, and micropollutants. If untreated, these contribute to eutrophication and environmental degradation. Microalgae-based bioremediation offers a sustainable solution, showing promise for pollutant removal and high-value bioproduct generation. This study evaluates the efficacy of Galdieria sulphuraria ACUF 427 in treating urban wastewater, with a focus on nutrient removal and phycocyanin production at different optical densities (OD 2, OD 4, and OD 6). Nutrient removal rates (RRs) were analysed for ammonium nitrogen (N-NH₄⁺), ammonia nitrogen (N-NH₃), phosphate phosphorus (P-PO₄³⁻), and chemical oxygen demand (COD). The RR for N-NH₄⁺ increased with optical density, reaching 7.49 mg/L/d at an optical density of 6. Similar trends were observed for N-NH₃ and P-PO₄³⁻, with peak removal at OD 6. COD removal remained high across all ODs, though differences between OD 4 and OD 6 were not statistically significant. Significant variations (p < 0.05) in nutrient removal were noted across the ODs, except for COD between OD 4 and OD 6. Biomass growth and phycocyanin production were significantly higher in the wastewater compared to the control (Allen Medium), with the most effective performance observed at an optical density (OD) of 6. Maximum growth rates were 0.241 g/L/d at OD 6, 0.178 g/L/d at OD 4, and 0.120 g/L/d at OD 2. These results highlight the potential of G. sulphuraria as an agent for wastewater bioremediation and the production of high-value compounds, particularly at elevated cell densities, where we achieved superior nutrient removal and biomass production. Full article

Engineered wetland has been used as a Best Management Practice (BMP) to remove pollutants and maintain water quality in watersheds. This study is focused on developing models to analyze the impacts of discharges on the efficiency of wetlands to improve water quality downstream. The watershed hydrological Soil & Water Assessment Tool (SWAT) and wetland (Personal Computer Storm Water Management Model—PCSWMM) models were developed to analyze the efficiency of engineered wetlands to remove the pollutants for different basins under three different climatic conditions (i.e., dry, average and wet year). The SWAT was calibrated and validated to simulate discharge and water quality parameters. The wetland model was developed using inflow hydrographs and concentrations of the water quality parameters biochemical oxygen demand (BOD), total suspended solids (TSSs), total nitrogen (TN) and total phosphorous (TP), simulated from a Soil & Water Assessment Tool (SWAT) model. A PCSWMM (wetland) was developed based on the physical and first order decay process within the wetland system for three basins in Prairie du Pont watershed in Illinois, USA. The results showed that pollutant removal efficiencies decreased from low to high discharges (dry to wet climatic conditions) for all watersheds and pollutants (except for BOD) based on trendline analysis. Nevertheless, the efficiencies were highly variable, specifically during low discharges. Furthermore, the sensitivity of the k-parameter (areal rate constant) was pollutant dependent. Overall, this study is helpful to understand the efficacy of wetlands’ pollutant removal as a function of discharge. The approach can be used in watersheds located in other geographic regions for the preliminary design of engineered wetlands to remove non-point source pollution and treat stormwater runoff. Full article