Water, Air, & Soil Pollution最新文献

The study investigates the structure, morphology, and adsorption properties of Gd-doped Ni-Co ferrites synthesized via a modified reduction method. Physicochemical analysis of the Gd-doped and undoped Ni-Co ferrites was conducted using TG-DTG-DTA, XRD, FT-IR, SEM, EDS, and BET techniques. The XRD analysis revealed an increase in the lattice parameter due to the substitution of Fe ions by Gd ions, impacting the crystallite size, which decreased from 14 to 4 nm. Additionally, the synthesized powders exhibited a well-developed mesoporous structure and a significantly increased specific surface area, reaching up to 139 m²/g. The study indicated that the presence of Gd(III) ions led to the distortion of octahedral sublattices, resulting in the formation of surface-active centers and a modification of the surface charge of the ferrites. This modification led to improved adsorption properties of Gd-substituted ferrites in solutions with natural pH. The adsorption studies demonstrated the enhanced capacity of the Ni_0.5Co_0.5Gd_0.05Fe_1.95O₄ sample of 254 mg(CR)/g and 298 mg(OTC)/g, which are three times and two times higher, respectively, compared to the undoped NCF sample. The adsorption mechanism was best described by the Langmuir model, indicating chemisorption during pollutant removal, supported by the calculated adsorption energy ranging from 14.74 to 18.90 kJ/mol. XPS and FTIR analyses showed that CR and OTC adsorption onto Gd-doped ferrite samples involves the chemisorption. The study concludes that the modified reductive coprecipitation method contributes to the formation of a mesoporous surface, while Gd substitution significantly enhances both surface charge and, as a consequence, the adsorption properties. This work sheds light on the potential of Gd doping to produce advanced adsorbents for water treatment.

Perchlorate is a persistent and long-lasting pollutant discovered in many water and food sources worldwide, causing widespread concern. It is a hormone disruptor that impacts human health by interfering with the thyroid gland's natural function. It is rapidly absorbed in humans and experimental animals following oral administration. Adults, fetuses, and neonates who are iodine-deficient may be particularly vulnerable to perchlorate sensitivity. Since perchlorate is widely present in surface water and groundwater, it is exposed to the aquatic environment. Solid fuels, ammunition, fireworks, fertilizers, vehicle airbag activators, and flares contain perchlorate as an oxidizing agent. Currently, many studies are being done on determining sources and remedial methods. For biological and environmental matrices, trace perchlorate levels have been measured in drinking water, sewage, milk, beer, blood, saliva, breast milk, fruits, and vegetables. The goal of this review focuses on analytical methods of perchlorate detection and prospects.

Graphical Abstract

In the past decade, numerous kinds of heavy metals have been discharged into water and soil environment, which are contaminants with high toxicity to both human beings and environment ecosystem. Biochar has been attracted wide attention due to its advantages of wide sources, large specific surface area and low cost, while biochar immobilized microorganisms also has been widely used to eliminate heavy metals from water and soil. To date, many studies about performance of biochar immobilized microorganism have been reported, but few studies had focused on the reaction mechanism of biochar immobilized microorganism for heavy metals remediation in water and soil. Thus, the recent advances toward the application of biochar-immobilized microorganism in the remediation of heavy metals from water and soil were systematacially summarized in this study, including the influence factors and reaction mechanism of biochar immobilized microorganism. Based on the above overview, the next study on biochar-immobilized microorganism has been prospected. This study could provide theoretical and technical support for biochar immobilized microorganisms in the remediation of heavy metal polluted water and soil.

Graphical Abstract

Recent years have seen a significant increase in microplastic contamination across terrestrial ecosystems, facilitated by various pathways such as atmospheric deposition, wastewater irrigation, and agricultural plastic mulching. This persistence of microplastics in soil raises concerns about their profound impacts on soil health and ecosystem dynamics. Key studies have highlighted detrimental effects, including reduced soil moisture retention, altered soil microbiota composition, and disrupted nutrient cycling processes. Moreover, microplastic pollution adversely affects soil biota, notably earthworms, crucial for soil nutrient cycling and structure maintenance, exhibiting reduced growth rates and increased mortality upon exposure. Notably, microplastics also influence soil microorganisms, potentially compromising overall soil health and ecosystem functioning. Co-exposure of microplastics and other contaminants can also synergistically exacerbate toxicity, impairing ecological balance. Evidence suggests negative repercussions on plant growth, including diminished seed germination rates and altered nutrient profiles in exposed plants. These findings underscore the urgent need for comprehensive reviews to synthesize existing knowledge, and identify research gaps, necessitating a focus on mitigation strategies. Addressing these issues is critical for safeguarding terrestrial ecosystems and ensuring sustainable environmental management in the face of increasing microplastic contamination.

Improper plastic disposal results in biological magnification since the plastics accumulated in the landfills and in the ocean find their way into the food web – getting increasingly accumulated at the top of the Ecological Pyramid. The degradation of plastic waste can be achieved by chemical, thermal, photo, and biological processes. Anaerobic co-digestion (AcoD) can be applied to biodegrade plastic waste and the organic fraction of municipal solid waste (OFMSW) while ensuring increased process stability and biogas production. While the anaerobic digestion (AD) or anaerobic mono-digestion of only plastics with high carbon content (higher carbon-to-nitrogen ratio) is challenging, the co-digestion with lower carbon-to-nitrogen ratio organic wastes results in increased biodegradation and biogas production. Pretreatment of plastic waste can surely enhance biodegradability and biogas yield, but further investigation is required to determine the economic viability of various pretreatment techniques available. This review highlights the classification of plastics based on their biodegradability, microbial species responsible for biodegradation, and the changes in the properties of plastics during biodegradation under AD and AcoD. Further, the review delves into the crucial process governing factors that affect AcoD and provides current insights for plastic biodegradation using AcoD.

Graphical Abstract

Red mud is a red, slurry-like waste produced by the alumina industry. The expansion of the alumina sector has significantly increased red mud production in recent years. Owing to its complex composition and high alkalinity, red mud poses serious risks of environmental degradation and causes resource wastage if left unmanaged. The comprehensive utilization of red mud remains minimal, with its primary applications limited to building materials, metal recovery, and ecological projects. This paper examines the mineral composition and physicochemical properties of red mud while briefly addressing its associated environmental risks. The ecological and environmental applications of red mud are reviewed, with particular emphasis on soil remediation, catalyst synthesis, and the development of red mud-based adsorbents. After providing a thorough overview of the previous research, we address these issues with respect to the use of red mud in environmental applications. Finally, the future direction of research related to red mud is envisioned.

Sediment contamination is a prevailing global environmental problem. Sediments in the lower sections of rivers are often contaminated by persistent organic pollutants (POPs). Among the POPs, polybrominated diphenyl ethers (PBDEs) raised deep concerns because of their multiple toxicities and endocrine-disrupting effects. Decabromodiphenyl ether (BDE-209) usually occupies more than 90% of the total PBDE concentration in sediments and is not easy to clean up. We have successfully developed the in situ phase inversion emulsification and biological reductive dehalogenation (ISPIE/BiRD) to remediate weathered polychlorinated biphenyls (PCBs) and hexachlorobenzene (HCB) in river sediments. Still, it has yet to be applied to BDE-209-contaminated sediments. Thus, in this study, we tested ISPIE/BiRD’s applicability on the sediments contaminated by BDE-209 in batch and column experiments and analyzed their metagenomic profiles. In the batch experiment, the best-performing group, Group 3, removed 56.5% of BDE-209 in 70 days. In the column study, ISPIE removed 22% and 15% of BDE-209 in the weathered and fresh groups, respectively. In addition, the best performance group for subsequent BiRD removal is the natural recovery group of weathered BDE-209 (WNR), with a total removal of 56.0%. According to the DNA sequencing data, more species and higher diversity in the batch experiment tend to perform better. The predominant bacteria in the column experiment differed from those in the batch experiment but showed similar removal functions. Rectinema cohabitans is the only species positively correlated with the removals in batch and column studies. The results suggested that ISPIE/BiRD is feasible for the remediation of BDE-209-contaminated sediment.

Mercury (Hg) is a global pollutant that poses significant risks to human health and ecosystems. In its dominant atmospheric form, gaseous elemental mercury (GEM), it can travel long distances, contributing to widespread environmental contamination. This study investigates GEM levels in ambient air across urban, suburban, rural, and industrial areas in Peninsular Malaysia using both in situ and continuous measurement methods. Results show GEM concentrations ranging from a minimum of 4.8 to a maximum of 28.9 ng m⁻3, with the highest levels observed in industrial areas such as Pasir Gudang (28.9 ng m⁻3) and Shah Alam (18.6 ng m⁻3). Health risk assessments (HRA), conducted for different age groups, indicated that GEM concentrations were below the threshold for non-carcinogenic health risks (HQ < 1). These findings highlight the urgent need for long-term monitoring to assess mercury pollution and inform Malaysia’s commitment to the Minamata Convention. The study underscores the importance of continuous GEM monitoring to bridge knowledge gaps in mercury’s spatial and temporal distribution, especially in tropical regions.

Soils developed on carbonates are susceptible to geogenic enrichment of potentially toxic trace metals (TMs) and thus present potential risks to the ecosystem and population. Clarifying factors that influence the bioavailability of TMs is crucial for soil risk control. This study aimed to investigate the bioavailability and speciation of TMs in limestone-derived soils in southwestern China where a large area was recognized as high geochemical background. The total, bioavailable content and speciation of TMs were analyzed by acid digestion, single and sequential extraction, respectively. The results showed that high contents of TMs in the acid-insoluble limestone residues resulted in the geogenic enrichment of Cr, Ni, Pb and Zn in soils. The risk assessment results showed that the ecological risks of TMs in the studied soils were low, except Cd. The DTPA extraction showed that the bioavailability of Pb and Cu was higher than Cr, Ni, and Zn, and the bioavailability of Pb and Cu in paddy soils was twice as high as in upland soils. In paddy soils, Cr, Ni and Zn reside in residual and Fe-oxides bound fractions, Cu and Pb are primarily hosted by residual, organically and Fe–Mn oxides bound fractions. Additionally, the mobility and bioavailability of Cu and Pb increased towards the surface. Soil organic matter is identified as a critical factor influencing the bioavailability of Pb and Cu. These findings highlight the potential risks of mobilizing geogenic TMs induced by organic matter in paddy soils.

Excess sludge (ES) and plant waste (PW) are two typical organic solid wastes in urban areas, and their co-fermentation is one of the key strategies in the circular economy. This study innovatively investigated the impact of the oxidant potassium ferrate (PF) on the anaerobic co-fermentation of ES and PW for the production of volatile fatty acids (VFAs) and elucidated the underlying mechanisms. The results indicated that PF could enhance the co-fermentation of ES and PW to produce VFAs, with an optimal dosage of 0.06 g/g (based on total suspended solids), yielding a maximum VFAs production of 261 mg chemical oxygen demand (COD)/g volatile suspended solids (VSS), which is 2.1 times that of the control group. High doses of PF inhibited microbial metabolism, reducing VFAs production, but still higher than the control group. PF effectively promoted the solubilization of organic matter in the ES and PW co-digestion system, increasing the concentrations of soluble COD, soluble protein, and soluble polysaccharides, with higher PF concentrations leading to more significant solubilization of available organic matter. PF increased the content of loosely bound extracellular polymeric substances (EPS) but decreased the content of tightly bound EPS. The oxidizing nature of PF suppressed the production of biogas, with only 99.5 mL/g VSS produced in the 0.08 g/g PF group. PF stimulated the concentration of ammonium nitrogen in the fermentation liquid of the co-digestion system but decreased the concentration of soluble phosphate.