Environmental Technology & Innovation最新文献

The release of pollutants of emerging concerns like antibiotics in the environment is posing serious threats to ecosystems. The aim of this study was to remove four antibiotics from the aqueous phase using polymer-based adsorbent in its raw form for antibiotic removal coupled with a mechanistic understanding of the process. Polyethylene, post-cleaning, served as an adsorbent, characterized for surface area, pore size, and structure. Two-week batch experiments at 25°C and pH 7 were conducted at a laboratory scale. Polyethylene demonstrated over 90 % removal efficiencies for all the selected antibiotics. Data fitting into various models revealed Langmuir isotherm and Elovich kinetic model governed the adsorption. Antibiotics, excluding ciprofloxacin, followed second-order kinetics; ciprofloxacin was governed by pseudo-first-order kinetics. Pseudo-second-order kinetics had R² values of 0.9855, 0.9746, and 0.9997 for ofloxacin, sulfamethoxazole, and oxytetracycline, respectively. Elovich had R² values over 0.90 for all the antibiotics, with the order of values as oxytetracycline>ofloxacin>sulfamethoxazole> ciprofloxacin. Langmuir Isotherm indicated the R² value of 0.9777, 0.9902, 0.9551, and 0.9959 for ofloxacin, ciprofloxacin, sulfamethoxazole, and oxytetracycline, respectively. Regeneration results exhibited that all antibiotics had greater than 80 % removal efficiencies in the first two cycles while the regeneration capacity of ciprofloxacin and sulfamethoxazole reduced to 75 % and 50 %, respectively at the fourth cycle. The effective removal of antibiotics indicates its usefulness and potential for widespread application compared to the costly and chemical-intensive adsorbents. These findings highlight the potential of selected adsorbents for real-time applications as the lab-scale studies mimicked the real environment by using a mixture of antibiotics.

Although the effectiveness of zero-valent iron (ZVI) and zero-valent manganese (ZVMn) in heavy metal removal is well-established, their combined synergistic potential for antimony (Sb) remediation from wastewater has remained largely unexplored. Addressing this gap, this study introduced a magnetic zero-valent iron-manganese bimetallic material (ZVIM), synthesized via the borohydride reduction method, to investigate its capabilities and underlying mechanisms for Sb reduction and adsorption. The ZVIM, characterized by a high specific surface area of 220 m²/g, exhibited a high adsorption capacity (614.6 mg/g for Sb(III) and 241.7 mg/g for Sb(V)), facilitating over 96.7 % removal for both Sb(III) and Sb(V). The adsorption conformed to the pseudo-second-order kinetic model, and the isotherm data aligned with the Freundlich model, indicative of a heterogeneous adsorption process. The removal of Sb(III) predominantly occurred via surface complexation and electrostatic adsorption to the positively charged ZVIM surface, accompanied by a partial oxidation of Sb(III) to Sb(V). In contrast, the elimination of Sb(V) was primarily facilitated through surface complexation mechanism, encompassing both reduction and electrostatic adsorption. The outcomes of this study shed light on the intricate interactions between Sb species and the ZVIM, revealing the material as a promising candidate for the efficacious removal of Sb from wastewater.

Although clay dispersion is one of the few techniques currently used in the field to control cyanobacterial harmful algal blooms (CyanoHABs), low flocculation efficiency and resuspension of flocculated algal cells are its main drawbacks. This study simulated the "flocculatio-lysis-degradation-nutrient regulation" model of biocontrol technique to develop a modified clay (ECRE-CS-PFS-CPL) using polyferric sulfate (PFS), chitosan (CS) and Eichhornia crassipes root extracts (ECRE) to modify the clinoptilolite (CPL). The results revealed that ECRE-CS-PFS-CPL introduced functional groups, specifically aldehyde group —CHO and amide group —CO-NH—, leading to an enhanced void structure. At 0.2 g/L concentration, ECRE-CS-PFS-CPL demonstrated a removal efficiency of 98.02 % within 30 min. ECRE-CS-PFS-CPL exhibited a positive charge in nature water, leveraging charge neutralisation to expedite the flocculation of M. aeruginosa cells. The combination of coated CS and algal cells resulted in the formation of large, dense flocs through net sweeping and bridging, which was 58.28 times larger than control. Subsequently, the loaded ECRE inhibited the algal cells via allelopathy. The inhibition activated the antioxidant system of M. aeruginosa, with significant increases in catalase (CAT) and superoxide dismutase (SOD) activities. Photosynthetic pigments (Chl-a), photosynthetic efficiency (Fv/Fm) and maximum relative photosynthetic electron transfer rate (ETRmax) were markedly reduced, indicating the damage to photosynthetic system. Furthermore, Chl-a remained consistently low during extended monitoring, registering at 4.98 % of control after 40 days. ECRE-CS-PFS-CPL effectively reduced microcystins by 81.48 % and phosphate levels in algal cultures by 91.92 % compared to control. Consequently, ECRE-CS-PFS-CPL offers an efficient, environmentally safe and sustainable solution for CyanoHABs control.

Addressing the urgent need for sustainable solutions in waste management, this study focuses on the pivotal task of recycling heavy metals from electroplating sludge (ES), a critical issue both environmentally and economically. The research introduces a novel leaching process utilizing pickling liquor as a reagent to extract valuable metals from the sludge. Key parameters such as agitation speed, solid to liquid ratio (S/L), temperature, and duration were examined to optimize the leaching rate. Results revealed impressive extraction rates, with 92.33 % Cr, 89.49 % Cu, and 89.59 % Ni extracted within 120 min from S/L 10 g/L, at 300 rpm, and 25 °C. However, it was noted that increasing temperature negatively impacted the leaching rate and led to the formation of undesirable compounds. X-ray diffraction (XRD) analysis identified gypsum and potassium jarosite as predominant compounds formed on the leaching residues at different temperatures of 25 °C and 45 °C. Field emission scanning electron microscopy (FE-SEM) illustrated significant morphological changes in the residues, indicating the influence of temperature on compound formation. Additionally, environmental risk assessment of the residues was conducted using synthetic precipitation leaching procedure (SPLP) and toxicology characteristic leaching procedure (TCLP) methods. In conclusion, this research underscores the promising potential of the developed leaching process using pickling liquor to reclaim valuable metals from ES. By optimizing parameters and assessing environmental risks, this study contributes to advancing environmentally sound practices in industrial waste management.

A special dust storm characterized by high PM₁₀ mass concentrations (921.9 ± 632.3 μg m⁻³) and high relative humidity (RH; 60.1 % ± 11.1 %) was observed on March 22–24, 2023 at a coastal city of North China. Aerosol particles of PM₁₀ were analyzed by a scanning electron microscope coupled with energy dispersive X-ray and an ion chromatograph. The results showed that individual mineral particles were dominated by clay minerals, followed by quartz, feldspar, and carbonate. Bulk water-soluble inorganic ions analysis showed that SO₄^2- mass concentrations varied from 3.7 μg m⁻³ to 23.3 μg m⁻³ with an average value of 12.4 μg m⁻³. However, their mass ratios to PM₁₀ were relatively stable, being 1.15–2.01 % with an average value of 1.49 % ± 0.25 %, similar to the value near the dust sources (Tengger Desert). Although S-containing individual mineral dust varied from 5.2 % to 70.7 %, the average weight ratio of S on individual mineral dust was 2.1 %, much lower than that of non-dust periods (11.0 %). The results suggested limited sulfate formation on mineral dust surfaces even under high RH. In contrast, NO₃^-, which was very limited in dust sources, varied from 0.21 % to 4.11 % of the total PM₁₀ with an average value of 1.61 % ± 1.07 %. The research highlighted that nitrate formation has exceeded sulfate formation during severe dust storm episodes, which might because the atmospheric compositions in China have changed significantly with a high mass ratio of NO₂/SO₂ after the implementation of the strict emission control measures.

Determining the hyperaccumulation mechanism of Solanum nigrum L., which exclusively accumulates cadmium (Cd), presents significant challenges due to the difficulty in identifying its unique characteristics. While some metabolic pathways related to Cd accumulation can be explored, there are no methods to ascertain if other heavy metals may share the same pathways. Isobaric tags for relative and absolute quantitation (iTRAQ) were employed to investigate the metabolic pathways associated with Cd hyperaccumulation and Cu accumulation (non-Cu hyperaccumulator) by comparing differentially expressed proteins (DEPs). The results showed that 27 intersecting DEPs reflecting relative metabolic pathways related to Cd accumulation were identified by comparing DEPs in leaves and roots, including carbon metabolism, aminoacyl-tRNA biosynthesis, phagosome, peroxisome, as well as starch and sucrose metabolism. These pathways might be responsible for the values of Cd enrichment factor (EF) and translocation factor (TF) exceeding 1, associated with key proteins participated in phosphoenolpyruvate, carboxylase, chloroplastic catalytic activity, and granule-bound starch synthase I. The combined metabolic pathways identified by 2 intersecting DEPs related to Cu accumulation could result in Cu EF >1 in the 0.2 Cu mg kg⁻¹ treatment, EF <1 in the 5 mg kg⁻¹ treatment, and TF<1 in both treatments, associated with key proteins, which might concern photosynthesis-antenna proteins and hydroxymethylbilane synthase. No metabolic pathways related to simultaneous accumulation of Cd and Cu has been identified. The identified DEPs were validated using Western blotting with five key proteins. Additionally, Western blotting and yeast mutant confirmed the presence of proteins related to carbon fixation in photosynthetic organisms, carbon metabolism, peroxisome, as well as starch and sucrose metabolism. Photosynthetic, O₂^•−, H₂O₂ and non-enzymatic antioxidants indices reflecting protein-related differences indirectly supported the above results. These findings are crucial for further exploration of the Cd hyperaccumulation mechanism.

Shortening the initial activation time and extending the duration of the thermophilic phase are key to improving compost product quality in cold-climate regions. This study set up three treatments that cattle manure (CM), manure with rice straw (MR), and manure with maize straw (MM) in the field with ambient temperature ranging from –6–7 ℃. Compared with traditional manure composting, composting with straw performed more effectively, and the effect of the addition of maize straw surpassed that of the addition of rice straw. Straw additives markedly increased the compost pile temperature and extended the thermophilic phase duration. In addition, straw addition improved compost product maturity, as indicated by the humic-like substance content, absorbance ratio, and germination index. To further illustrate this result, the microbial community structure during the composting process was studied. During the thermophilic phase, straw additives, especially maize straw, improved the formation of a diverse aerobic bacterial community and a unitary thermophilic fungal community, and promoted a stronger relationship between the bacterial and fungal communities, as revealed by co-inertia analysis. The abundance of functional genes indicated that straw addition increased the activities of organic carbon degradation and transformation. This study demonstrated the necessity of enhancing the interaction between thermophilic–aerobic bacteria and thermophilic fungi to improve compost product quality.

The disparities in exposure to environmental hazards have fueled the environmental justice movement, which has garnered increasing attention and momentum over the past few decades. However, research addressing exposure disparities pertaining to chemicals remains notably limited. Here, leveraging data from the National Health and Nutrition Examination Survey spanning the period from 1999 to 2018, we unveiled that the perfluorooctanesulfonic acid (PFOS) exhibited the highest concentration in human biomonitoring in general U.S. population, with a mean value of 14.54 ± 19.59 ng/ml. Subsequently, the mean concentrations of Perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), and perfluorodecanoic acid (PFDA) were 3.33 ± 3.19, 2.29 ± 3.13, 1.07 ± 1.30, and 0.34 ± 0.71, respectively. Meanwhile, although females or Non-hispanic White exhibited relatively higher levels for most per- and polyfluoroalkyl substances (PFASs) compared to other groups. The individuals with higher household incomes demonstrated elevated exposure to PFASs. Interestingly, despite lower exposure burdens were observed in Non-Hispanic Black individuals, females, and individuals with low family income, we identified relatively higher exposure disparities in these populations. In particular, exposure disparities for general U.S. population exposure to PFOS exhibited an approximate 50 % increase from 1999 to 2018, despite a concurrent decline of 84 % in biomonitoring levels. Meanwhile, the population aging has led to an exacerbation of human exposure to PFOS by 12.4 %. Our findings underscore the necessity of ensuring equitable protection from PFAS exposure for all populations, although further investigation is required to understand the underlying mechanisms driving these disparities.

Microplastics have now become an emerging contaminant with high concern in the Arctic and Sub-Arctic Region. Here, the Kongsfjorden system in the Arctic has been investigated for abundance, distribution, and characteristic of microplastics in surface seawater. Eighteen samples were collected using an in-situ filtration sampling method, and then analyzed by Fourier-transform infrared spectroscopy. The average abundance of microplastics in surface seawater was 3.6 items m⁻³, with an abundance range of 0.0—10.0 items m⁻³. The highest abundance of microplastics was located adjacent to the eddy in Kongsfjorden, where a microplastic accumulation zone might have formed. Microplastics transported by ocean currents and those from local discharges might converge in this zone. Two sampling stations were set up at the wastewater treatment plant outfall, which showed an abundance range of 4.0—6.0 items m⁻³, slightly higher than the average abundance. Of the six polymer types identified, rayon, polyester and polyamide were the most common composition. Proportions in fiber form in surface water was 84.6 %, and blue (28.2 %) and transparent (25.6 %) were predominant colors. Most microplastics (>90.0 %) were less than 1 mm in the longest dimension. This study provided important baseline data as well as a practical microplastic sampling method for polar marine environments.