Frontiers of Environmental Science & Engineering最新文献

Magnetotactic bacteria reside in sediments and stratified water columns. They are named after their ability to synthesize internal magnetic particles that allow them to align and swim along the Earth’s magnetic field lines. Here, we show that two magnetotactic species, Magnetospirillum magneticum strain AMB-1 and Magnetospirillum gryphiswaldense strain MSR-1, are electroactive. Both M. magneticum and M. gryphiswaldense were able to generate current in microbial fuel cells with maximum power densities of 27 and 11 µW/m², respectively. In the presence of the electron shuttle resazurin both species were able to reduce the crystalline iron oxide hematite (Fe₂O₃). In addition, M. magneticum could reduce poorly crystalline iron oxide (FeOOH). Our study adds M. magneticum and M. gryphiswaldense to the growing list of known electroactive bacteria, and implies that electroactivity might be common for bacteria within the Magnetospirillum genus.

Polyethersulphone (PES) membranes modified with urethane functional groups were prepared through an interfacial reaction using electron beam irradiation. The removal of eight endocrine disrupting chemicals (EDCs) was studied using both pristine and functionalized PES membranes. The prepared membranes underwent characterization using several techniques, including attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, scanning electron microscopy, contact angle analysis, and measurements of pure water flux. Furthermore, dynamic adsorption experiments were conducted to evaluate the adsorption mechanism of the prepared membrane toward the eight EDCs. The urethane functionalized membranes were hydrophilic (52° contact angle) and maintained a high permeate flux (26000 L/h m² bar) throughout the filtration process. Dynamic adsorption results demonstrated that the introduction of urethane functional groups on the membranes significantly enhanced the removal efficiency of 17β-estradiol, estriol, bisphenol A, estrone, ethinylestradiol, and equilin. The adsorption loading of 17β-estradiol on the functionalized PES membrane was 6.7 ± 0.7 mg/m², exhibiting a 5-fold increase compared to the unmodified PES membrane. The membranes were successfully regenerated and reused for three adsorption cycles without experiencing any loss of adsorption capacity.

Constructed wetlands (CWs) are widely used to treat secondary effluent. However, simultaneously removing ammonia (NH₄⁺-N) and nitrate (NO₃⁻–N) is challenging because of insufficient oxygen and carbon sources. In this study, a novel composite material (MPCM) comprising MnO₂ and polycaprolactone was developed as a substrate for CWs to enhance the synchronous removal of NH₄⁺–N and NO₃⁻–N. The CWs with a higher MPCM content (H-CW), lower MPCM content (L-CW), and controlled CW (C-CW) exhibited average NH₄⁺–N removal efficiencies of 75.69%, 70.49%, and 52.40%, respectively. The ¹⁵N isotope tracking technique showed that NH₄⁺–N removal was attributed to anaerobic ammonia oxidation mediated by MnO₂ reduction (Mnammox), which accounted for 17.16%–27.24% of the NH₄⁺–N removal in the composite material layers (0–20 cm) of the H-CW and L-CW. The richness of ammonia oxidizers in the upper layers (40–50 cm) of the H-CW and L-CW further facilitated NH₄⁺–N removal. Moreover, the average total nitrogen (TN) removal efficiencies of the H-CW and L-CW were 1.99 and 1.59 times that of C-CW, respectively, owing to enhanced denitrification by MPCM. Furthermore, N₂O emissions were reduced by 81.31% and 70.83% in the H-CW and L-CW, respectively. This study provides an effective approach for improving nitrogen removal and reducing N₂O emissions during the treatment of secondary effluent by CWs.

Polycyclic aromatic hydrocarbons (PAHs) present significant risks to human health owing to their carcinogenic, teratogenic, and mutagenic properties. The contamination of surface water with PAHs via runoff has become a prominent source of water pollution. While the capacity of bioretention systems to remove PAHs from runoff is recognized, the dynamics of PAH migration and degradation in these systems are not well-understood. This study aims to explain the migration and fate of PAHs in bioretention systems through a series of experiments and model simulations. This study constructed bioretention systems with three different media types and found that these systems achieved PAH load reductions exceeding 92%. Notably, naphthalene (NAP), fluoranthene (FLT), and pyrene (PYR) tended to accumulate in the media’s upper layer, at depths of 10 to 40 cm. To further analyze the migration and fate of PAHs during multi-site rainfall events and across prolonged operation, we applied the HYDRUS-1D model under three distinct scenarios. The findings of this study indicated that NAP degraded in 40 d, whereas FLT and PYR showed incomplete degradation after 120 d. During continuous rainfall events, there was no clear pattern of PAH accumulation; however, FLT and PYR persisted in the bioretention systems. The combination of experimental and simulation findings highlights the inevitable accumulation of PAHs during extended use of bioretention systems. This research provides a theoretical basis for improving operational efficiency, advancing PAH degradation in bioretention systems, and reducing their toxicity.

Effective removal of emerging contaminants (ECs) to minimize their impacts on human health and the natural environment is a global priority. For the removal of ECs in water, we fabricated a seaweed spherical microsphere catalyst with Cu cation-π structures by in situ doping of Cu species and ascorbic acid in mesoporous silica (Cu-C-MSNs) via a hydrothermal method. The results indicate that bisphenol A (BPA) is substantially degraded within 5 min under natural conditions, with its biological toxicity considerably weakened. Moreover, industrial wastewater could also be effectively purified by Cu-C-MSNs/H₂O₂ system. The presence of metal sites and the complexation of ECs via cation-π interaction and π-π stacking on the catalyst surface were directly responsible for the polarization distribution of electrons, thus activating H₂O₂ and dissolved oxygen (DO). The removal of contaminants could be attributed primarily to 1) the activation of H₂O₂ into ^•OH to attack the contaminants and 2) self-cleavage because of the transfer of electrons from the contaminants to the catalysts. This study provides an innovative solution for the effective treatment of ECs and has positive implications for easing global environmental crises.

We assessed the situation of endosulfan residues in cotton fields after the endosulfan ban came into effect and the current knowledge, attitude, and practice (KAP) of cotton farmers on the phase-out of endosulfan and the application of alternative technologies. Topsoil samples (n = 91) of cotton fields were collected from the major cotton-producing areas in China, namely the north-west inland cotton region, and the endosulfan residues were analyzed. A KAP survey was carried out for cotton farmers, and 291 questionnaires were distributed. The influences of gender, age, education background, cotton planting years, publicity and training, income sources, and other factors on cotton farmers’ KAP were analyzed. The results showed that endosulfan sulfate was the main endosulfan residue in the soil, followed by β-endosulfan and α-endosulfan, the average residual contents were 0.569, 0.139, and 0.060 µg/kg, respectively. The results of the KAP study showed that cotton farmers scored low on knowledge about the phase-out of endosulfan and the application of alternative technologies but high on attitude and practice. The number of family members, years of cotton planting, age, and the cotton-planting area had different degrees of influence on KAP scores. The training could significantly improve the KAP scores of cotton farmers; training should be more targeted and designed reasonably for key groups, such as men and the population under 30, followed by training them to use pesticides safely. For large-scale cotton growers, training should focus on green prevention and control technologies.

Flow-electrode capacitive deionization (FCDI) is an innovative technology in which an intermediate chamber plays an important role in the desalination process. However, relatively few studies have been conducted on the structures of these intermediate chambers. In this study, we propose a novel flow-electrode capacitive deionization device with a spindle-shaped inlet chamber (S-FCDI). The desalination rate of the S-FCDI under optimal operating conditions was 36% higher than that of the FCDI device with a conventional rectangular chamber (R-FCDI). The spindle-shaped chamber transferred 1.2 µmol more ions than the rectangular chamber, based on energy per joule. Additionally, we performed a detailed analysis of different inlet chamber shapes using computational fluid dynamics software. We concluded that S-FCDI has a relatively low flow resistance and almost no stagnation zone. This provides unique insights into the development of intermediate chambers. This study may contribute to the improvement of the desalination performance in industrial applications of FCDI.

Iron-based catalysts have been widely used to treat refractory organic pollutants in wastewater. In this paper, magnetic Co-γ-Fe₂O₃ was synthesized by a facile tartaric acid-assisted hydrothermal method, and Co-γ-Fe₂O₃/MoS₂ nanocomposite catalyst was obtained via in situ growth of MoS₂ nanosheets on Co-γ-Fe₂O₃ nanoparticles. The nanocomposite catalysts were used to decompose bisphenol A (BPA) by activating peroxymonosulfate (PMS). It was shown that only 0.15 g/L catalyst and 0.5 mmol/L PMS degraded 10 mg/L of BPA (99.3% within 10 min) in the pH range of 3–9. PMS was activated due to redox cycling among the pairs Co(III)/Co(II), Fe(III)/Fe(II), and Mo(VI)/Mo(IV). Quenching experiments and electron paramagnetic resonance spectroscopy demonstrated that both radical and non-radical pathways were involved in BPA degradation, in which active radical sulfate radical and non-radical singlet oxygen were the main reactive oxygen species. Ten intermediates were identified by liquid chromatography-coupled mass spectrometry, and three possible BPA degradation pathways were proposed. The toxicity of several degradation intermediates was lower, and Co-γ-Fe₂O₃/MoS₂ exhibited excellent reusability and could be magnetically recovered.

Awareness of the adverse impact of air pollution on attention-related performance such as learning and driving is rapidly growing. However, there is still little known about the underlying neurocognitive mechanisms. Using an adapted dot-probe task paradigm and event-related potential (ERP) technique, we investigated how visual stimuli of air pollution influence the attentional allocation process. Participants were required to make responses to the onset of a target presented at the left or right visual field. The probable location of the target was forewarned by a cue (pollution or clean air images), appearing at either the target location (attention-holding trials) or the opposite location (attention-shifting trials). Behavioral measures showed that when cued by pollution images, subjects had higher response accuracy in attention-shifting trials. ERP analysis results revealed that after the cue onset, pollution images evoked lower N300 amplitudes, indicating less attention-capturing effects of dirty air. After the target onset, pollution cues were correlated with the higher P300 amplitudes in attention-holding trials but lower amplitudes in attention-shifting trials. It indicates that after visual exposure to air pollution, people need more neurocognitive resources to maintain attention but less effort to shift attention away. The findings provide the first neuroscientific evidence for the distracting effect of air pollution. We conclude with several practical implications and suggest the ERP technique as a promising tool to understand human responses to environmental stressors.

Radiocesium is frequently present in radioactive wastewater, while its removal is still a challenge due to its small hydrated radius, high diffusion coefficient, and similar chemical behavior to other alkali metal elements with high background concentrations. This review summarized and analyzed the recent advances in the removal of Cs⁺ from aqueous solutions, with a particular focus on adsorption and membrane separation methods. Various inorganic, organic, and biological adsorbents have undergone assessments to determine their efficacy in the removal of cesium ions. Additionally, membrane-based separation techniques, including reverse osmosis, forward osmosis, and membrane distillation, have also shown promise in effectively separating cesium ions from radioactive wastewater. Additionally, this review summarized the main approaches, including Kurion/SARRY system + desalination system and advanced liquid processing system, implemented after the Fukushima Daiichi nuclear power plant accident in Japan to remove radionuclides from contaminated water. Adsorption technology and membrane separation technology play a vital role in treatment of contaminated water.