Water, Air, & Soil Pollution最新文献

Colour is typically the initial pollutant identified in wastewater. Membrane separation represents a novel approach to separation processes, with expectations of supplanting many traditional separation systems. The aim of this study is to investigate polymer inclusion membranes (PIMs) consisting of tri octyl methyl ammonium chloride as the carrier, tributylphosphate as the modifier, poly-vinyl chloride as the base polymer and 2-Nitro phenyl pentyl ether as the plasticizer for removing an acid dye (Red Erionyl A-3G) from aqueous solution. The dye adsorption on the membrane surface and its transition to the stripping phase was achieved by placing the membrane between two glass cells. Changing the stripping solution ensured both adsorption on the membrane surface and the transfer of all the dye to the stripping stage. Using a mixture of 0.8 M salicylic acid and 0.8 M NaOH, along with stirring at 1000 rpm during the stripping phase, extraction efficiency reached 98% in the feed phase and 53% in the stripping phase. When 1 M NaOH solution was employed as the stripping solution, the membrane absorbed all the dye within 10 minutes, but there was no transition to the stripping phase. The membrane has a durability of 2 days.

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Using environmentally friendly technologies to meet the environmental issue of wastewater is very essential. With this regard, a novel PANI@Er-doped ZnO (PEZ) ternary heterojunction was synthesized using ultrasonic-assisted wet impregnation method. This PEZ heterojunction was found enhanced photocatalytic efficiency with better stability in comparison of their counter parts. All parameters of synthesized samples were explored by XRD, UV-DRS, FE-SEM, EDAX, PL, and UV–Vis Spectroscopy to measure the detoriation rate. Significant photodegradation efficiency against methylene blue (MB) was observed nearly 89% in neutral medium in 90 min. The direction of migration of charge carriers, degradation in rate of recombination of photo-generated electron–hole pairs, and their effective separation of synthesized nanocomposite were responsible for this boost up degradation. UV-DRS and PL studies were conducted to assess the energy band gap that determines the absorption behavior of the produced photocatalyst and validate the active interactions of dopant metals with Polyaniline backbone chains. Pseudo -first order relation, best adjusted by an R² value of 1, best characterized the kinetic studies of methylene blue for all synthesized samples. Therefore, it can be said that Er-ZnO is a unique multifunctional material with applications as a catalyst for the breakdown of organic dyes and an improvement in catalytic behavior upon integration of organic material PANI. The obtained PANI@Er-doped ZnO nanocomposites are anticipated to be effective photocatalyst for the elimination of methylene blue in aqueous environment.

Acidic wastewater from mining activities contains a large amount of Sb(III). Biochar can provide with an economical and efficacious method for removing of Sb(III). However, highly efficient removal was still challenging under acidic environment. In this study, bamboo charcoal biochar and rice straw biochar were modified with glutaraldehyde and chitosan to examine their Sb(III) adsorption performances in terms of adsorption isotherms, adsorption kinetics and thermodynamics under different treatment conditions, i.e. biochar dosages, pH values, adsorption durations, coexisting substances and temperatures. Characterizations including Brunauer–Emmett–Teller surface area analysis, Fourier transform infrared spectrometry, scanning electron microscope coupled with energy dispersive X-ray spectrometry as well as X-ray photoelectron spectroscopy were employed to further reveal the mechanisms. Results showed that the modified bamboo biochar and modified rice straw biochar showed excellent Sb(III) adsorption efficiency of 94.29% and 93.36%, respectively, under strongly acidic environment. The maximum Sb(III) adsorption capacities of the modified bamboo biochar and modified rice straw biochar reached to 81.16 mg/g and 72.92 mg/g, respectively. Langmuir adsorption isotherm model and quasi-secondary kinetic model best described the adsorption processes. Thermodynamic studies showed that the adsorption of Sb(III) by modified biochar was a spontaneous, exothermic and irreversible process. It was proposed that electrostatic attraction, complexation with functional groups (e.g., C = O, -NH₂, -OH), as well as oxidation of Sb(III) were involved in the adsorption processes. The modified biochar has greater removal capacity for Sb(III) than pristine one, suggesting its potential applications for the wastewater treatment.

Reverse osmosis (RO) membranes have been widely applied in the advanced treatment of chemical mechanical polishing (CMP) wastewater. However, membrane fouling persists in practical treatment processes. Herein, a hybrid coagulation-ultrafiltration (UF)-RO (CUR) system was used to control the fouling of the RO membrane, and a novel composite coagulant was developed to enhance the coagulation efficacy for CMP wastewater. Compared to traditional processes, the improved Coagulation-UF process exhibited a remarkable capacity, removing 98.62% of total silica and achieving complete turbidity removal in CMP wastewater. Furthermore, the aluminum residual was reduced by 76.47%, and the normalized flux of the RO membrane increased from 0.87 to 0.95. Moreover, the new coagulant achieved remarkable coagulation effectiveness, with silica and turbidity removal rates reaching 97.29% and 99.87%, respectively, while reducing residual aluminum to 15.50%. Notably, dissolved silica in CMP wastewater emerged as the primary contaminant on the surface of the RO membrane. The net sweep was the primary coagulation mechanism of the new coagulant, proving good performance in reducing the burden on both UF and RO membranes. These results exhibit significant implications for designing efficient pretreatment schemes for CMP wastewater and optimizing the longevity of RO membranes in semiconductor plants.

Graphical Abstract

Antimonate (Sb(V)), sulfate and acid orange 7 (AO7) are common pollutants in printing and dyeing wastewater. Currently, there have been no reports about the effects of sulfate and AO7 on Sb(V) removal by anaerobic granular sludge (AnGS). In this study, the Sb(V) removal and Sb(Ш) accumulation was revealed in presence of sulfate and AO7, and the role of adding granular activated carbon (GAC) was investigated. Results showed that sulfate inhibited Sb(V) removal by AnGS (S + Sb, k = 0.101). GAC alleviated the inhibition of sulfate on Sb(V) removal and Sb(V) removal rate increased by 1.9 times (GAC + S + Sb, k = 0.187). Meanwhile, GAC promoted sulfate reduction by AnGS. AO7 inhibited sulfate reduction, thereby alleviating the inhibition of sulfate on Sb(V) removal, and Sb(V) removal rate increased by 1.5 times (S + Sb + dye, k = 0.147). When Sb(V), sulfate and AO7 coexisted, adding GAC actually inhibited Sb(V) removal (GAC + S + Sb + dye, k = 0.067), which may be due to GAC promoted the reduction of sulfate and AO7 by AnGS. The microbial community analysis revealed that Acinetobacter genus was related to Sb(V) reduction, with higher relative abundance in GAC + S + Sb (49.4%) and S + Sb + dye groups (28.9%). These results provided guidance for anaerobic treatment of printing and dyeing wastewater.

Graphical Abstract

In the present study, based on continuous acid–base potentiometric titration experiments of argillaceous limestone-derived yellow soil obtained at different depths in Pingba, Guizhou, a 1-site/2-pK_a generalized composite surface complexation model (SCM) was established to obtain relevant parameters and explore soil surface acid–base properties. The model was employed to simulate cadmium (Cd) adsorption behavior. Combining the physicochemical properties of yellow soil and acid–base titration curves, the SCM-derived concentrations (H_s) and densities (D_s) of the surface-active sites for three soil layers showed decreasing trends with an increase in depth, whereas the calculated soil charge zero point (pH_pzc) values matched the experimental values, indicating the applicability of SCM in studying the surface acid–base properties of yellow soil. Furthermore, as the pH increased, Cd shifted gradually from the dissolved to the adsorbed state, achieving complete adsorption at a pH of ~ 7. The model-simulated Cd adsorption curve matched well with the experimental curve; the Cd adsorption behavior corresponded with the simulated distribution of surface sites at different pH levels, with ≡SOH₂⁺ and ≡SO⁻ being the main forms at pH < pH_pzc and pH > pH_pzc, respectively. Correlation analysis indicated that organic matter and goethite played a major role in H_s, whereas the charge zero points of soils at different depths were determined mainly by clay minerals, such as illite and iron-aluminum oxides. Our study established a scientific and reasonable relationship between the soil physicochemical properties and model parameters, providing a basis for preventing heavy metal pollution behavior via the effective application of model predictions.

In this study early signs of deterioration of the ecosystem in the Boka Kotorska Bay were assessed by applying an active biomonitoring approach for the first time in coastal area of Montenegro. Gilthead sea bream (Sparus aurata), commercially farmed in the Bay, was used as a bioindicator. Specimens were translocated from an aquaculture farm to more impacted sites within the Bay. After two weeks of exposure, the level of DNA damage was assessed in blood cells by comet assay and micronucleus test while muscle tissues were prepared for trace element determination. The results confirmed that an active biomonitoring approach is a valuable tool for eco/geno-toxicological assessment in the marine environment. Comet assay was sensitive in discrimination of the studied groups, moreover it was sensitive enough to detect stress related to the caging procedure and translocation of animals. Lack of feeding during the exposure period was reflected on the condition index. Based on the Integrated Biomarker Response (IBR), the group exposed at the main port - Porto Montenegro was shown to be under higher environmental stress than groups exposed at reference site Dobrota (IBM) and fish farm CogiMAR. An increase in the frequency of micronuclei was evident only at this site (Porto Montenegro). Obtained trace element concentrations in fish tissues were significantly lower in comparison to values recommended by the national legislative.

Abstract

The environmental contaminant 1,3-Dinitrobenzene (1,3-DNB), which contains two nitro groups (-NO₂), has a +III nitrogen atom oxidation state, and is susceptible to electron acceptance, and subsequent reductive degradation. In this study, carpet grass was investigated as a potential source of polyphenols for the reductive degradation of 1,3-DNB. A characterization of carpet grass revealed a rapid release of polyphenols from the grass in aqueous solution, and an increase in reduction capacity. The effects of the amount of grass in solution, and effects of the pH of the aqueous phase were examined. It was found that higher grass doses (e.g., 50 g L^-1) in solution resulted in complete removal of 1,3-DNB in the aqueous phase after 7 d reaction, regardless of the pH level. Kinetic analysis of 1,3-DNB degradation and its reaction intermediates, 3-nitroaniline (3-NA) and 1,3-phenylenediamine, indicated that the overall observed degradation rates (2.51-3.17 × 10^-2 h^-1) were similar across different doses of carpet grass, but found that the dose did impact the formation and degradation of 3-NA. Based on the results, a potential soil mixing treatment for 1,3-DNB contaminated soils, consisting of the blending of carpet grasses with soils was proposed. Soil slurry experiments simulating field remediation application suggested that enhanced degradation of 1,3-DNB contaminated soils can be achieved under reaction conditions with an appropriate solution volume and sufficiently high grass doses. This research offers valuable insights into the utilization of carpet grass for potential soil remediation through its incorporation into soils contaminated with 1,3-DNB.

Graphical Abstract

Proposed oil extraction in the Amazon River estuary raises significant concerns among environmentalists and scientists due to the environmental risks associated with this activity. Beyond oil pollution-associated risks, multiple classes of pollutants are threatening Brazilian ecosystems. In this Letter, we draw attention to this environmental issue and highlight actions to control the deleterious effects of pollution on Brazil’s biodiversity.

The contamination of soil with cadmium (Cd) poses a significant risk to both food safety and human health. It is crucial to urgently identify an effective technology for remediating Cd-contaminated soil. In the present study, a novel sulfur modified biochar supported ferrous sulfide (FeS@SBC) composite was fabricated by calcination and hydrothermal method. Indoor culture, column leaching, and pot experiments were employed to examine the immobilization effect of FeS@SBC on Cd in contaminated soil. The outcomes illustrated a significant immobilization effect on the Cd-contaminated soil with the application of FeS@SBC. After incubating the soil with the stabilizer for 28 d, the Cd that was previously highly mobile underwent a transformation into an immobilized state. In the experiment on leaching using simulated acid rain, the treatment with FeS@SBC showed a noteworthy decrease in the cumulative loss and leaching efficiency of Cd when compared to the control experiment. It achieved reductions of 70.9% and 71.6%, respectively. The adsorption and immobilization mechanisms resulted from co-precipitation, ion exchange and surface complexation. In the outdoor pot experiment, after 28 d of growth, the water spinach in contaminated soil treated with FeS@SBC has a better growth compared to the control group, with a biomass increase of 134.95%. Additionally, the values of BCF and TF of Cd decreased by 62.25% and 40.39%, respectively, and the available concentration of Cd in the soil decreased by 23.87%. The FeS@SBC composite shows promise as an effective stabilizer for remediating Cd-contaminated soil.