Environmental Science and Pollution Research最新文献

This study explores the use of functionalized manganese oxide (K-MnO₂-NH₂) for the removal of hexavalent chromium (Cr(VI)) ions, a highly toxic heavy metal contaminant, from wastewater. The synthesis of K-MnO₂-NH₂ was achieved through a two-step process, followed by comprehensive characterization using various analytical techniques, which confirmed the material's formation as a pure phase. The K-MnO₂-NH₂ exhibited exceptional chromium removal efficiency, achieving up to 90% (4.53 mg/g) of Cr(VI) removal at pH 2. This high efficiency is attributed to the incorporation of amine groups via functionalization with 3-aminopropyltriethoxysilane (APTES), which introduces active sites with a strong affinity for Cr(VI) ions. Kinetics studies indicated that a chemical reaction governs the adsorption process, while thermodynamic data suggested it to be exothermic, and thermodynamic data reveal the process to be exothermic. The Freundlich isotherm best described the adsorption behavior. The Cr(VI) adsorption capacity of K-MnO₂-NH₂ was determined to be 45.17 mg/g. K-MnO₂-NH₂ effectively removed Cr(VI) from industrial wastewater, achieving a removal efficiency of around 41% (25.5 mg/g) and visible discoloration showing excellent reusability, maintaining over 80% removal efficiency after five cycles without requiring regeneration. This innovative approach highlights the potential of K-MnO₂-NH₂ as a sustainable and effective solution for Cr(VI) removal in environmental remediation and water purification.

Chromium (Cr) is an ever-present abiotic stress that negatively affects crop cultivation and production worldwide. High rhizospheric Cr concentrations inhibit nutrients uptake and their translocation to aboveground parts, thus can affect the growth and development of crop plants. This experiment was designed to evaluate the effects of sole and combined zinc-lysine and iron-lysine applications on photosynthetic efficacy, antioxidative defense, oxidative stress, and nutrient uptake and translocation under Cr stress. Chromium stress exhibited toxic effects on the growth, physiological, and biochemical indices of pearl millet. The combined application of zinc-lysine and iron-lysine significantly decreased malondialdehyde (MDA; 25%) and hydrogen peroxide (H₂O₂; 22.44%), while increased superoxide dismutase (SOD; 19.75%), catalase (CAT; 26.16%), peroxidase (POD; 19.62%), and ascorbate peroxidase (APX; 23.52%) activities under Cr toxicity compared to the control treatment. In addition, the combined application of zinc-lysine and iron-lysine effectively improved net photosynthesis (43.63%), stomatal conductance (20.05%), transpiration rate (20.14%), internal CO₂ concentration (34.28%), total chlorophyll (43.12%), relative water content (23.95%), membrane stability index (32.77%), and proline content (25.53%) under stress condition and compared with control. Our results also indicated that the combined application of zinc-lysine and iron-lysine decreased Cr uptake in both shoot and root by 31.25% and 32%, and increased zinc and iron uptake by 39.28% and 36.67%, respectively, over the control, under Cr stress conditions. Moreover, under stress conditions, combined zinc-lysine and iron-lysine effectively improved growth traits particularly shoot and root dry weights, by 8% and 36.84%, respectively, over the control treatment. Overall, our results demonstrated that combined zinc-lysine and iron-lysine was more effective in mitigating Cr toxicity in pearl millet compared with the sole application of these treatments or the control.

Leather manufacturing is the process of converting raw animal hides or skins into finished leather. The complex industrial procedures result in a tanning effluent composed of chemical compounds with potentially hazardous impacts on humans and ecosystems. Among the traditional and efficient wastewater treatments, adsorption is an effective and well-known approach, able to manage a wide range of contaminants from wastewater. Among the plethora of adsorption substrates used on an industrial scale, zeolites have traditionally shown remarkable performances. Differently from other types of adsorbents, zeolites can also work as cation exchangers, which can remove cationic contaminants without influencing the anionic content of the effluent and (in specific cases) also when the removal process is endothermic. Zeolites are minerals naturally present in the environment, but they can be also easily synthesized and modified to enhance their water remediation features. However, the removal efficiency of zeolites is strictly dependent on the type of target contaminant because its uptake capacity is linked to its chemical and physical characteristics, especially on the surface interlayer. This review intends to present a general description of the tannery process to understand the origin and characterization of tanning wastewater. The core of the study aims to approach the most significant studies about zeolite applications in the removal of tanning contaminants. Drawbacks of the reviewed literature are further discussed, and some potential future research content is eventually revealed by identifying the issues that need further investigation.

Anthropogenic pressures affect large stretches of Mediterranean coastal environments, determining alterations, including chemical pollution, able to impair ecosystem functioning and services. Among the pollutants of major concern for their toxicity and persistence, there are polycyclic aromatic hydrocarbons (PAHs), which can be effectively monitored through bioaccumulation approaches. However, the main biomonitor of PAHs in the Mediterranean Sea, Posidonia oceanica, is currently undergoing extensive regressions due to anthropogenic pressures, forcing the search for alternative biomonitors. In this context, with a view to evaluate the effectiveness of the red alga Laurencia microcladia as an alternative PAH biomonitor, we comparatively investigated the accumulation gradients of 14 PAHs in its thalli, in leaves of P. oceanica and in surface sediments collected from different sites along the Cilento coast (southern Italy). The two species mainly absorb PAHs from water rather than sediments and show comparable PAH concentrations, with a preferential accumulation of low molecular weight PAHs in L. microcladia and of medium molecular weight PAHs in P. oceanica. Although with different accumulation profiles, both macrophytes highlighted comparable concentration gradients of anthracene and benzo[a]pyrene across study sites and the highest concentrations near a harbour. The obtained findings indicate that L. microcladia can be considered an effective biomonitor of PAHs in coastal ecosystems.

Today, there are environmental problems all over the world due to the emission of greenhouse gasses caused by the combustion of diesel fuel. The excessive consumption and drastic reduction of fossil fuels have prompted the leaders of various countries, including Iran, to put the use of alternative and clean energy sources on the agenda. In recent years, the use of biofuels and the addition of nanoparticles to diesel fuel have reduced pollutant emissions, improved the environment, and enhanced the physicochemical properties of the fuel. The current research deals with the experimental evaluation of emissions and performance of a diesel engine running on graphene nanopowder together with diesel-biodiesel-ethanol blends. The engine variables studied included the engine speed (in three stages 1800, 2200, and 2600 rpm) and three types of fuel including graphene nanoparticles (with values of 25 and 50 ppm), biodiesel (with volume percentages of 4, 6, and 8), and ethanol (with volume percentages of 2 and 4). The results showed that the power and torque of the D86 + B8 + E6 + G50 fuel increased on average by 20.26% and 28.76% at all engine speeds compared to the D100 fuel. The use of D86 + B8 + E6 + G50 fuel resulted in a significant reduction in CO (38.84%), UHC (21.24%), and NOx (19.92%) emissions compared to D100 fuel. In addition, a significant increase in CO₂ emissions (23.19%) was observed. The results of this study clearly show that the use of biofuels and the addition of nanopowder to D100 fuel are very effective methods to improve combustion, performance, and emission characteristics in diesel engines.

Lubricants are pivotal in mitigating friction and wear between surfaces, ensuring seamless movement of solid objects. However, the predominant use of petroleum-based lubricants in the automotive and industrial ssectors raises substantial concerns for future energy security. The exploration of vegetable oils as an alternative lubricant in the automotive industry was motivated by the depletion of fossil fuels and escalating environmental concerns. The post-pandemic surge in environmental awareness has intensified the focus on biolubricants. Over the past two decades, the biolubricants field has burgeoned with numerous research, signaling a heightened interest in eco-friendly and sustainable lubrication solutions. This underscores biolubricants as a dynamic and evolving research area with lasting prominence, especially amid ongoing environmental innovation. The review centrally revolves around naturally sourced lubricants, primarily focusing on vegetable oils, which stand out as appealing substitutes for conventional petroleum-based lubricants due to their biodegradability, high lubricity, and elevated flash points. The article delves into modifications to enhance vegetable oil properties, explores the role of additives, and provides insights into current and future prospects. The paper also investigates diverse applications in engine oil, grease, hydraulic oil, and more.

The aim of the current investigation is to explore the novel application of pumpkin, papaya, and orange peels as growth substrates for microalgae cultivation, with the overarching goal of advancing a sustainable "Agro to Agro" biorefinery paradigm. The research evaluates the integration of waste management practices into microalgal production, optimizing growth parameters to maximize output. Optimal concentrations of 2.8 mg L^-1 for orange peels, 35.5 mg L^-1 for papaya peels, and 35.5 mg L^-1 for pumpkin peels were identified, alongside a light intensity of 163.7 µmol m^-2 s^-1 and a nitrogen concentration of 0.8 g L^-1. Under these conditions, Chlorella sorokiniana demonstrated peak biomass production of 3.16 g L^-1, lipid productivity of 1.55 g L^-1, and carotenoid productivity of 9.18 mg L^-1, additionally, yielding significant amounts of palmitic acid (47.9%) and lutein. The study further explored the conversion of residual microalgae into biochar, with optimal pyrolysis conducted at 350 °C. The as-synthesized biochar was utilized effectively as a soil amendment for cultivating Vigna radiata. The present study underscores the viability of a closed-loop biorefinery approach, demonstrating the recycling of pumpkin, papaya, and orange peels as effective substrates for microalgae cultivation and subsequent biochar conversion for potential industrial applications. The promising results of the study advocate to the feasibility of this integrated model for sustainable future.

The presence of antibiotics in the environment is of significant concern due to their adverse effects on aquatic ecosystems. This study provides an assessment of potential ecological risks (RQ) associated with the concentrations of eight antibiotics and antiparasitics (amoxicillin-AMO, azithromycin-AZI, ciprofloxacine-CIP, ofloxacine-OFL, oxfendazole-OXF, lincomycin-LIN, sulfacetamide-SCE and sulfamethoxazole-SME) in the surface water of 13 urban lakes in Hanoi city, Vietnam during the period 2021-2023. The findings revealed considerable variations in the total concentrations of these 8 substances (T_AB), ranging from below the method detection limit (< MDL) to 2240 ng L^-1 with an average of 330.4 ng L^-1. Among the 8 antibiotics and antiparasitics examined, OXF, AMO, and SCE were undetectable, while the others were present at a range of concentrations (in ng L^-1): OFL: 129 (< MDL-1530); CIP: 87.1 (< MDL-608); LIN: 72.7 (< MDL-676); SME: 41.5 (< MDL-504); AZI: 0.03 (< MDL-1). The calculated RQ values for these antibiotics in the Hanoi lakes indicated a high ecological risk for OFL and CIP to bacteria, a medium to high risk for SME for phytoplankton, a high risk for LIN to phytoplankton, while the risk for invertebrates was deemed negligible for all antibiotics across all lakes. The strong, positive correlation between T_AB concentrations and different microbial and environmental variables (Escherichia coli, ammonium, phosphate, and chemical oxygen demand) suggests that untreated domestic wastewater is the primary pollution source in these Hanoi lakes. These results should be used to raise public awareness and to encourage the implementation of strategies targeted at managing antibiotic use. They also underscore the need to reduce inputs of untreated, antibiotic-containing wastewater into urban lakes, such as those in Hanoi and advocate for the establishment of national limits for antibiotic concentrations in surface water.

Invasive alien plants pose a great threat to local plants and ecosystems. How to effectively alleviate this hazard is an unresolved issue. This study explored the carbon release characteristics of an invasive plant Spartina alterniflora and evaluated the ability of nitrogen removal from shrimp culture wastewater through constructing seawater wetland. The results showed that fresh S. alterniflora had a significantly higher carbon release potential and bioavailability than that of withered S. alterniflora, and alkali-heat treatment could increase the carbon release with an average COD release rate of 33.39 mg/g from fresh S. alterniflora. The removal rate of total nitrogen was improved by about 22% in seawater constructed wetlands by adding fresh S. alterniflora biomass. Moreover, the addition of fresh S. alterniflora biomass was beneficial to the increase in the abundance of denitrification-related genera Vibrio, which might be the key to the improvement of nitrate removal efficiency in seawater constructed wetland systems. These findings indicated that invasive plants S. alterniflora as carbon sources of seawater wetland was a feasible and effective resource utilization strategy.

Environmental consequences of petroleum mulch application are crucial in regions prone to wind erosion and desertification. This study aimed to assess the long-term effects of petroleum mulching on soil polycyclic aromatic hydrocarbon (PAH) concentrations and the associated human and ecological risk indices. These indices include incremental lifetime cancer risk (ILCR), hazard index (HI), toxic equivalent concentration (TEQ_BaP), toxic unit (TU), and risk quotient (RQ) in soil samples from Khuzestan province, Iran. Soil samples were collected from two depths: surface soil (0-10 cm) and deep soil (10-50 cm) across four regions with varying durations of petroleum mulch application: less than 5 years (T5), 5-20 years (T20), 20-30 years (T30), and 30-40 years (T40), and a control sample without mulching. Gas chromatography-mass spectrometry (GC-MS) was used to analyze the concentrations of 19 PAHs and 23 groups of alkylated PAHs (alkyl PAHs) in the soil. Petroleum mulching significantly impacted heavily contaminated soil samples (T5 and T20) with PAH levels ranging from 2.03 to 2.08 mg kg^-1. Older samples (T30 and T40) showed lower contamination levels (0.29 and 0.41 mg kg^-1), primarily due to the alkylated compounds. ILCR, HI, TEQ_BaP, TU, and RQ indices were highest in T5 and T20 surface samples, indicating high risk in T5 surface soil from RQ and moderate risk in the others, despite low cancer and non-carcinogenic risks. Although the risk from the compounds, particularly alkyl PAHs, has decreased over time, they could still adversely affect the ecosystem, emphasizing the use of environmentally friendly alternative mulches in such areas.