International Journal of Environmental Science and Technology最新文献

This study investigates the synthesis and characterization of recycled nylon (r-Nylon)-based nanofiber membranes incorporated with carbon black nanoparticles (CB NPs) and copper oxide nanoparticles (CuO NPs) for efficient ammonia gas adsorption. The primary objective of the study is to enhance adsorption performance by incorporating CB NPs and CuO NPs into r-Nylon nanofibers. The inclusion of CB NPs and CuO NPs increased the nanofiber diameter, with average diameters of 296.70 ± 39.69 nm for r-Nylon, 455.81 ± 115.65 nm for r-Nylon/CB, and 685.96 ± 165.96 nm for r-Nylon/CB/CuO, due to higher viscosity and slower solvent evaporation during electrospinning. X-ray diffraction (XRD) analysis showed a decrease in crystallinity: 61.10% for r-Nylon, 60.04% for r-Nylon/CB, and 49.53% for r-Nylon/CB/CuO, attributed to particle agglomeration. Fourier-transform infrared (FTIR) spectroscopy confirmed the successful incorporation of CB NPs and CuO NPs into the nylon matrix. Nanoparticles incorporation reduced porosity, while BET analysis revealed increased surface area due to nanoscale pore formation. Mechanical testing confirmed enhanced load-bearing capacity, supporting the membrane’s suitability for structurally demanding filtration applications. Adsorption tests revealed that the r-Nylon/CB/CuO composite achieved the highest initial ammonia removal efficiency (92.27%) and exhibited slower saturation, maintaining 60.60% removal efficiency at 30 min. In contrast, the r-Nylon/CB membrane maintained 62.91% efficiency after 30 min. Temperature-Programmed Desorption of Ammonia (TPD-NH₃) analysis highlighted that CuO NPs addition enhanced the acidity and active site density, improving the adsorption performance. These findings demonstrate that r-Nylon/CB/CuO nanofiber membranes hold strong potential for application in mitigating ammonia emissions from agricultural activities.

Spent caustic is considered among the most hazardous pollutants in industrial wastewater produced from refining industries. Extensive studies have been conducted based on various treatment techniques and materials to achieve the highest removal efficiency. Fenton and electro-Fenton techniques are among the methods regarded with great interest for this purpose in recent years. In this study, the electro-Fenton technique was implemented as a subset of advanced oxidation processes for COD removal from spent caustic effluents of the 8th refinery of Iran's South Pars gas complex using solar panels as a renewable energy source. Influential parameters such as H₂O₂/COD, current density, pH, and reaction time were selected, and response surface methodology was implemented using Design Expert software for experimental design. The optimal operating conditions were H₂O₂/COD = 1.264 mL/L, pH = 5.865, current density = 20.144 mA/cm², and reaction time = 35 min, resulting in 94.43% COD removal. In addition, by synthesizing the MWCNT-Fe₃O₄ nanocomposite as a nano-absorbent, the electro-Fenton sludge was treated, and the effluent quality was improved. Based on the results, electro-Fenton technology is proposed as an environmentally friendly and efficient technique for caustic treatment, while the hybrid technique improves wastewater quality by removing the remaining pollutants.

Water pollution remains a pressing global issue, especially due to the increasing prevalence of emerging contaminants such as pharmaceuticals, micro/nanoplastics, and endocrine-disrupting compounds. These pollutants pose significant risks to ecosystems and human health due to their persistence, bioaccumulation, and resistance to conventional treatment methods. This review critically examines both traditional and advanced water remediation technologies, including adsorption, electrochemical and Fenton-based oxidation, membrane filtration, bioremediation, phytoremediation, and the use of nanomaterials. Particular attention is given to innovative approaches, such as the integration of microorganisms with nanomaterials and plant–microbe consortia, which offer enhanced degradation pathways for recalcitrant contaminants. A comparative analysis highlights the advantages, limitations, and sustainability aspects of each method, providing insights into their practical application. By addressing recent trends and future perspectives, this work contributes to the development of more effective and eco-friendly strategies for mitigating the growing challenge of emerging pollutants in water systems.

Graphical abstract

Background

Non-exhaust particulate emissions from railway systems are increasingly recognized as a key contributor to indoor air pollution, particularly in underground metro environments. Among these sources, pantograph–catenary contact has received limited experimental attention, despite its potential to generate metallic fine and ultrafine particles that affect passenger exposure and tunnel air quality.

Methodology

A laboratory-scale pantograph–catenary simulation apparatus was developed to reproduce urban-rail operating conditions under non-electrified settings. Two representative contact-strip materials—metallized carbon and copper-based sintered alloy—were tested at sliding speeds of 20, 30, and 40 km h⁻¹, corresponding to Seoul Metro operations. Three travel phases (acceleration, constant speed, deceleration) were simulated, and airborne particles were continuously monitored using a Grimm 11-D optical particle counter covering 0.25–35 µm across 31 size channels.

Results

Distinct differences in emission behavior were observed. Copper-based alloys produced higher mass concentrations, whereas metallized carbon emitted significantly greater numbers of ultrafine particles. Particle emissions increased by approximately 60% with rising speed and peaked during deceleration, reflecting transient contact-force fluctuation and frictional instability at the interface.

Conclusions

Pantograph–catenary interaction constitutes a major non-exhaust particle source even without electrical arcing. Effective mitigation should emphasize operational control—such as speed regulation, contact-force stabilization, and low-emission material design—to reduce airborne particle concentrations in enclosed railway environments.

This study investigates the synergistic potential of co-cultivating Chlorella vulgaris and Scenedesmus obliquus to optimize microalgal biomass production and enhance the removal efficiency of cadmium and copper ions. Co-culture experiments were conducted at different microalgal ratios, and the sample with the highest biomass concentration was selected for the biosorption experiments. Heavy metal ions were added separately to the algal suspension at its maximum optical density, and removal efficiency was measured using atomic absorption spectroscopy. The results demonstrated that a 1:1 species ratio significantly increased biomass concentration, reaching nearly 4 g L⁻¹. The biosorption capabilities of the microalgal co-culture were also assessed, revealing impressive removal efficiencies for heavy metals, with cadmium being more readily accumulated than copper. Maximum removal percentages of 66.77% for cadmium and 68.38% for copper were recorded at lower metal concentrations, indicating the potential of the co-culture system for bioremoval applications. However, increased metal concentrations adversely impacted removal efficiency, likely due to the formation of metal complexes that hinder metabolic processes. FTIR analysis identified characteristic functional groups involved in the biosorption process, confirming the significance of carboxyl groups in binding heavy metal ions. Initially, the rapid uptake of metal ions was driven by electrostatic interactions and complexation. As biosorption progressed, it transitioned to chemisorption, revealing limitations due to the availability of active sites on algal cells at higher concentrations. The differential absorption efficiencies for cadmium and copper further illustrate the complexities of microalgal interactions with heavy metals, with copper-induced oxidative stress negatively affecting algal growth and biosorption capacity.

The human health risk associated with the byproducts of synthetic chemicals in wastewater treatment is a major concern globally. Hence, the need to adopt a new approach in the treatment of wastewater to minimize the occurrence of these byproducts. Natural product application has provided an alternative approach that could minimize the occurrence of the byproducts. The present review collated information that will aid in the justification of the use of natural products in solving environmental problems. The information on the sustainability of the natural products application in wastewater treatment was provided. Outlook based on the sustainable and renewable wastewater treatment strategies was discussed. The natural products applied in wastewater treatment include the extract from plants (Cactus latifaria, Opuntia ficus-indica, and Moringa oleifera), animals (chitosan and chitin), and microorganisms (Aspergillus sp. and Streptomonas sp., Spirulina platensis and Chlorella vulgaris). Based on the collated information, they were found to be crucial and effective in the removal of contaminants from wastewater. In addition, the cost of application is less when compared to the synthetic chemical application. Although natural products application in wastewater treatment is a promising approach, gaps still exist in their application especially in a large-scale wastewater treatment. Standardization of the natural products for sustainable contaminants removal is recommended in wastewater treatment processes.

Remediation of industrial effluents is critical for controlling land pollution and protecting the environment from heavy metal toxicity. In the present research, textile industry effluents were collected from two different processing stages (dyeing and finishing) and treated with Scenedesmus quadricauda (green microalga) and Phormidium bohneri (filamentous blue green alga) to reduce water pollution. S. quadricauda and P. bohneri were cultivated in the industrial effluents in different dilutions of wastewater (T₁, T₂, T₃ and T₄) and T₀ was taken as control. The primary metals to be studied were lead, chromium, cadmium, mercury, and arsenic. The results demonstrated significant reductions in key water quality parameters, including total dissolved solids (65%), hardness (70%), calcium (70%), magnesium (75%), chemical oxygen demand (75%), biological oxygen demand (78%), and chlorides (85%), are indicating the potential of S. quadricauda and P. bohneri as a phycoremediation agent. P. bohneri achieved (100%) removal of lead and chromium (99.72%) in T₄ treatments during finishing and dyeing stages, outperforming S. quadricauda, reaching (99.27%) lead and (97.96%) chromium removal. S. quadricauda and P. bohneri showed significant contaminants and heavy metal filtering properties which may help maintaining the heavy metals at sub toxic levels. The current findings highlight the potential of P. bohneri and S. quadricauda as a sustainable and cost-effective solution for treating textile wastewater. Additionally, the treated water produces algal biomass, thereby promoting a circular economy.

The western Liaoning Province agro-pastoral ecotone, located on the transitional margin of the northern agro-pastoral zone, has experienced significant substantial climate and land-use changes over the past 30 years (1990–2020). This study investigates the spatial and temporal changes in climate and land-use, assesses key ecosystem services, and quantifies the impacts of these changes on ecosystem service provision. In addition, we project future land-use patterns and ecosystem service outcomes under multiple scenarios using the PLUS and InVEST models. The results show that habitat quality has consistently declined, particularly along riverbanks and urban fringes, while carbon storage also decreased significantly during the study period. Soil retention capacity in hilly regions weakened, whereas high-altitude areas maintained relatively high levels of both carbon storage and soil retention. Spatial detector analysis confirms that both climate variability and land-use change exert significant and differentiated influences on ecosystem services. The study’s contributions lie in its comprehensive evaluation of ecosystem service changes in a vulnerable yet strategically important region, providing a scientific basis for sustainable land-use planning and ecological management. Future scenario projections indicate a continued decline in carbon storage, accompanied by modest improvements in habitat quality and water yield, while soil conservation capacity is expected to decrease sharply. Together, these findings underscore the complex interaction between land-use change and climate drivers and offer valuable insights for regional ecological conservation and policy-making.

This study investigates the impact of microplastics (HDPE, PP, PET) on soil enzyme activities (urease, alkaline phosphatase, β-glucosidase), which are crucial for biogeochemical cycling, and their interaction with urea, a widely used nitrogen fertilizer. Soil samples from farmland in Bursa, Turkey, were treated with microplastics at 0%, 0.5%, and 5% concentrations and urea at 0 and 20 mg/100 g, then incubated aerobically (at 28 °C and 70% field capacity) for 60 days. Enzyme activities and pH were measured at 20, 40, and 60 days, and two-way ANOVA was used for statistical evaluation. Results showed that higher microplastic concentrations (5%) significantly reduced enzyme activities, with urease decreasing by approximately 17–33%, β-glucosidase by 14–34%, and alkaline phosphatase by 10–25%. Among microplastic types, PET had the least inhibitory effect, while PP and HDPE caused stronger reductions. Urea application partially alleviated enzyme inhibition at low microplastic concentrations, enhancing activity by 15–20%, but failed to counteract suppression at higher doses. These findings highlight the disruptive impact of microplastics on soil biochemical processes, reducing nutrient cycling efficiency and compromising soil health. While urea application offers some mitigation, its effectiveness is limited in microplastic-contaminated soils. This study underscores the urgent need for integrated soil management strategies to minimize the dual threats of microplastic pollution and declining fertilizer efficiency, ensuring long-term soil sustainability.