Environmental Nanotechnology, Monitoring and Management最新文献

Water quality assessment is becoming an increasingly important aspect of environmental management. Regular assessment of water quality is essential to ensure the safety of aquatic ecosystems as well as human health. This study aimed at assessing water physicochemical and microbiological proprieties of Lake of Birds (northeastern Algeria). Water samples were monitored monthly (December 2021–November 2022) from three different sites. Quantification of bacterial groups (total heterotrophic bacteria, total coliforms, faecal coliforms, and faecal Streptococci) was coupled with physicochemical characterization of the water (temperature, pH, turbidity, dissolved oxygen (DO), electrical conductivity, total suspended solids, nitrates, nitrites, ammonium, phosphates, biological oxygen demand (BOD5), calcium, magnesium, chloride, potassium, sulfates and hardness). The results of this study were compared with Algerian standards and World Health Organization guidelines. The results show that the water in Lake of Birds has an alkaline pH (9.24), poor oxygenation (DO = 0.55 mg/L), turbidity > 5 NTU, BOD5 > 5 mg/L, potassium > 20 mg/L, and with a very high levels of eutrophic substances (NO₂^–, NH₄⁺ and PO₄^3–). Moreover, the results of the bacteriological analysis indicated the existence of faecal contamination that exceeds the standards, with health risks for humans. Further studies are needed including emerging contaminants and other factors that may impact aquatic ecosystems and to determine how best to maintain their cleanliness and sustainability.

Globally, more than 200 million people are exposed to elevated concentrations of arsenic in groundwater, thus representing an important environmental and public health problem. Apart from inorganic species, water quality suffers also from the occurrence of organic pollutants discharged by the food sector like whey, a by-product of the dairy industry. The valorisation of these organic residues is relevant to reduce water pollution and to develop new materials for different applications. This research reports the synthesis and evaluation of a novel adsorptive activated carbon composite modified with whey protein amyloids for arsenic removal from water. The adsorbent was characterized with FT-IR spectroscopy, X-ray diffraction, N₂ physisorption, pH at point of zero charge determination, and thermogravimetric analysis. Experimental adsorption kinetics and isotherms of arsenic removal were determined at optimal pH 5.0, best fitted with the PSO and Sips model, respectively. The corresponding maximum adsorption capacity for As⁵⁺ was 0.16 mmol g⁻¹ through an endothermic process. Surface complexation was the predominant phenomenon in the adsorption mechanism as the As-O bond was formed via whey’s functional groups, hydroxyl, amine, and amide, with the latter having the strong affinity to arsenate as elucidated by the HSAB theory. This study highlights the potential of whey protein as a raw material to produce added-value products and its performance as a precursor of novel adsorbents for water purification, therefore minimizing their associated disposal cost and addressing relevant environmental concerns such as arsenic contamination.

Despite technological development, the textile industry still generates effluents with a high content of emerging contaminants, which are harmful to the environment. Conventional wastewater treatment methods struggle to remove emerging contaminants, necessitating advanced techniques. One promising solution is the modification of membranes and adsorption methods. The same modifying agents were used to modify the surface of microfiltration membranes and to create an adsorbent, allowing a comparison of the two processes in water treatment contaminated with dyes. Copper oxide nanoparticles were produced through green synthesis, and polyethersulfone microfiltration membranes were surface-modified using graphene oxide and copper oxide nanoparticles via a pressure-assisted method. Among the tested membranes, MF_GO_1.0 + CuO_3.0 showed the best performance, demonstrating a synergistic effect between the modifying agents, efficiently removing 97.69 % of Levafix Blue CA dye and recovering 84.88 % of the flux. It also exhibited outstanding removal rates (>99 %) for other textile dyes, such as Solophenyl Blue and Reactive Black 5. Membrane characterization revealed a decrease in contact angle for membranes modified with CuO and GO-CuO, rendering them more hydrophilic and improving permeability. Scanning Electron Microscopy depicted a compacted membrane, characteristic of graphene oxide, with nanoparticles on the surface. Chemical stability tests, conducted at neutral pH for 7 days, demonstrated no significant variation in permeability and contaminant removal. Although adsorption had limited effectiveness in removing the Levafix Blue CA dye, it provided valuable insights into the underlying mechanisms. Comparing membrane modification with adsorption, membranes displayed more efficiency in dye removal and showed enhanced antifouling properties. These results indicate the potential of modified membranes in treating dye-containing wastewater. As dye production increases, these innovative technologies offer promising solutions to reduce the environmental impact of textile industry effluents. By employing such advanced methods, we can work towards safeguarding our water resources and ecosystems from the harmful effects of textile wastewater pollution.

To combat the issues of energy scarcity and environmental pollution, a visible-light responsive, ternary photocatalyst (Cu-CaTiO₃-GO) was fabricated, by photo-depositing Cu nanoparticles over a CaTiO₃-GO binary composite. The physicochemical characteristics of Cu-CaTiO₃-GO were investigated using XRD, HR-TEM, FE-SEM, EDS-mapping XPS, Raman, FT-IR, BET, EIS, UV–vis DRS, and PL techniques. In comparison with pristine CaTiO₃, and binary composites (Cu-CaTiO₃, CaTiO₃-GO), the ternary hybrid exhibited superior photocatalytic activity for H₂ generation as well as antibiotic cefixime (CFX) degradation. Under LED light, the rate of H₂ generation over Cu-CaTiO₃-GO accumulated to 57.69 mmolh⁻¹, while the photodegradation efficiency for CFX reached 94.1 % in 100 min with 53.4 % of TOC removal. The upgraded performance is credited to synergistic effects of Cu NPs (SPR effect), CaTiO₃ (specialized cuboid-like morphology), and GO (high conductivity), co-existing in the trio-hybrid, which resulted in a greatly increased surface area, an expanded spectral response range, a stronger adsorption property, efficient charge migration and separation extent. Ternary catalyst performed well even in the 4 recycling tests (retaining 79.4 % CFX removal and 52.51 mmolh⁻¹ H₂ evolution efficiency). In Cu-CaTiO₃-GO system, the electron transport channel (Cu → CaTiO₃ → GO) with adequate band potentials effectively supports both photocatalytic oxidation and reduction. Photoelectrons are enriched and transferred by plasmonic Cu, and then captured by GO, an e^- sink. This maximizes composite photo redox capability, rapidly generating active radicals (OH), and (O₂^-), degrading CFX to simpler molecules and reducing proton to H₂. The effectiveness of Cu-CaTiO₃-GO was even tested in the real water matrices. Besides, degradation intermediates of CFX were elucidated using LC-MS, and the decomposition pathway was suggested. Finally, the probable photocatalytic reaction mechanism was deduced for both the degradation and H₂ generation processes. The current study proposes a non-noble transition metal-based perovskite-type photocatalytic material for both clean energy generation and wastewater treatment.

The photoactive bismuth materials represent an interesting tool for facing the complexity represented by the organic contained wastewater streams and the engineering of their chemical and surface properties is the key to a solve the water pollution. In this review, we are discussing the use of bismuth based materials for photooxidative treatment of polluted water critically evaluating and highlighting the strengths and the weaknesses of the approach with a focus on the properties of the materials but reporting as well the currently available technologies providing an agile reference point in the field.