Cotekidd8760

In this study, a five-stage stepwise precipitation process, including pre-sedimentation, magnesium removal, gypsum precipitation, ettringite precipitation and calcium removal, was proposed as a softening pretreatment for zero liquid discharge system for flue gas desulfurization wastewater. Batch tests and long-term bench-scale experiment showed that magnesium, sulfate and calcium were efficiently removed with efficiencies all above 98.0%, leaving a clean effluent majorly containing NaCl and NaOH. TDI-011536 research buy The precipitated CaSO4, CaCO3, Mg(OH)2 and ettringite were completely separated by stepwise precipitation, and the purity of Mg(OH)2 and ettringite were further enhanced by washing and soaking treatment. CaSO4 and CaCO3 can be directly recycled as gypsum product and desulfurizing agent within the power plant, while Mg(OH)2 and ettringite presented proper particle size and excellent thermal properties as a synergistic flame retardant. The flame retardancy of ethylene vinyl acetate copolymer were greatly improved when blended with recovered Mg(OH)2 and ettringite, and possessed better performance by blending them together because ettringite could act as a dispersing and compatible agent of Mg(OH)2, and relieve the intensity of smoke releasing. Chemical sludge recovery compensates the total cost of the five-stage process by 45.0%, and makes the process technically versatile, economically beneficial and environmentally friendly without solid waste production.Introducing membrane filtration into advanced oxidation processes to decrease energy and cost consumption has been considered as a promising direction in environmental remediation. In this work, we firstly developed a kind of novel lawn-like Fe2O3@Co0.08Fe1.92@nitrogen-doped reduced graphene oxide@carbon nanotube composites (FeCo@GCTs) through in-situ pyrolysis of self-assembly of Prussian blue analogues and GO, followed through a vacuum-assisted filtration strategy to fabricate 2D confinement freestanding GO composite membrane. Electrochemical analysis and H2-TPR revealed the superiority of FeCo@GCTs as ideal electron acceptor, and this unique lawn-like structure concentrated active sites with a confined space and enriched oxygen vacancies that realized 98.5% (0.128 min-1) sulfamethoxazole degradation via peroxymonosulfate activation, and accelerated the reduction of Cr(VI). Owing to the increasing interlayer spacing of GO nanosheets, the permeation flux of FeCo@GCTs/GO membrane has not only been attained to 487.3 L·m-2·h-1·bar-1, which was more than 7.5-fold of GO membrane (64.6 L·m-2·h-1·bar-1), but also achieved the synergistic membrane filtration and catalytic degradation of pollutants. Furthermore, scavenger experiments and EPR tests were conducted to confirm the active radicals, of which SO4·- and 1O2 were responsible for SMX degradation. Therefore, these features demonstrated great potential for the fabricated 2D confinement catalytic membrane with enriched oxygen vacancies in wastewater purification.This study presents an extended thermodynamic and phenomenological combined model to mitigate the environmental hazardous acid gas over composite membranes. The model has been applied to an acid gas such as carbon dioxide (CO2) for its permeation through polyetherimide incorporated montmorillonite (Mt) nanoparticles hollow fiber asymmetric composite membranes. The well-established non-equilibrium lattice fluid (NELF) model for penetrating low molecular weight penetrant in a glassy polyetherimide (PEI) was extended to incorporate the other important polymer/filler system features such as tortuosity in acid gas diffusion pathways resulted from layered filler aspect ratio and concentration. The model mentioned above predicts the behavior of acid gas in PEI-Mt composite membranes based on thermodynamic characteristics of CO2 and PEI and tortuosity due to Mt. The calculated results are compared to experimentally determined values of CO2 permeability through PEI-Mt composite asymmetric hollow fiber membranes at varying transmembrane pressures and Mt concentrations. A reasonable agreement was found between the model predicted behavior and experimentally determined data in terms of CO2 solubility, Mt concentration and aspect ratio were calculated based on average absolute relative error (%AARE). The proposed modified model efficiently predicts the CO2 permeance across MMMs up to 3 wt% Mt loadings and 6 bar pressure with ± 10%AARE.Lead sulfide nanoparticle (nano-PbS) released into environment can cause hazards to human or ecosystem. Nano-PbS potentially undergoes oxidation in the environment, but oxidation mechanism is not understood yet. Herein, oxidation kinetics and products of nano-PbS by ozone (O3), hydrogen peroxide (H2O2) and hydroxyl radical (HO·) in the atmosphere or natural water were investigated. Results show that oxidation process of nano-PbS can be divided into three stages, producing sulfate, ions and oxides of lead in sequence. O3 or HO·leads to faster release of ionic lead from nano-PbS in the initial stage than H2O2, but causes significant decrease of ionic lead by transforming divalent lead to tetravalent lead oxides in the second or third stage. Toxicity determined taking Chlorella Vulgaris as an example follows an order of PbO2 less then Pb3O4 less then nano-PbS less then PbO less then PbSO4. Toxicity of lead particles is mainly determined by sizes influencing cellular uptake and solubility product constant (Ksp) related with dissolution of lead in cells. The results indicate that the toxicity of nano-PbS increases in an initial oxidation stage and decreases in further oxidation stages. This study provides new insights into environmental behavior of nano-PbS and mechanism understandings for assessing ecological risks of nano-PbS.The chiral pesticide enantiomers often show selective efficacy and non-target toxicity. In this study, the enantioselective degradation characteristics of the chiral organophosphorus insecticide isocarbophos (ICP) by Cupriavidus nantongensis X1T were investigated systematically. Strain X1T preferentially degraded the ICP R isomer (R-ICP) over the S isomer (S-ICP). The degradation rate constant of R-ICP was 42-fold greater than S-ICP, while the former is less bioactive against pest insects but more toxic to humans than the latter. The concentration ratio of S-ICP to R-ICP determines whether S-ICP can be degraded by strain X1T. S-ICP started to degrade only when the ratio (CS-ICP/CR-ICP) was greater than 62. Divalent metal cations could improve the degradation ability of strain X1T. The detected metabolites that were identified suggested a novel hydrolysis pathway, while the hydrolytic metabolites were less toxic to fish and green algae than those from P-O bond breakage. The crude enzyme degraded both R-ICP and S-ICP in a similar rate, indicating that enantioselective degradation was due to the transportation of strain X1T. The strain X1T also enantioselectively degraded the chiral organophosphorus insecticides isofenphos-methyl and profenofos. The enantioselective degradation characteristics of strain X1T make it suitable for remediation of chiral organophosphorus insecticide contaminated soil and water.Chinese liquor distillers' grain (CLDG) is an abundant industrial organic waste showing high potential as feedstock for biofuel conversion. In this study, CLDG was used as substrate by microbial community in pit mud to produce medium-chain fatty acids (especially caproate). Simulated and real fermentation were used to evaluate the effect of ethanol and lactic acid being the electronic donors (EDs) during the anaerobic chain elongation (CE). The caproate concentration was achieved at 449 mg COD/g VS, with the corresponding high carbon selectivity at 37.1%. Microbial analysis revealed that the domestication of pit mud increased the abundance of Caproiciproducens (converting lactic acid into caproate) and Lactobacillus (producing lactic acid), leading to enhanced caproate production. The lactic acid conversion facilitated in full utilization of ethanol through CE consumption. The coexistence of EDs benefited the CE system and that this green energy production can be a promising high-performance biofuel donor for sustainable industrial production development.Mass transfer efficiency and catalytic reactivity are the two major hurdles for heterogeneous catalytic wet peroxide oxidation (CWPO) technologies. To address these issues, nanocomposite CuFeO2/Al2O3 was synthesized and assessed as a novel catalyst for enhanced adsorption and oxidation of anionic pollutants (catechol and reactive red 195 (RR195)) in waters. With a positive charge on the nanocomposite by introducing Al2O3, the adsorption of anionic pollutants was promoted. The surface complexation reaction on CuFeO2/Al2O3, which fits well to the Langmuir isotherm, has engined the mass transfer of pollutants to the nanocatalyst that demonstrated 96.46% and 99.75% removal of catechol and RR195 at pH 3, respectively. CuFeO2/Al2O3 also showed good performance in various reaction media including binary pollutants system and real wastewaters. The hydroxyl radical in aqueous solution played a major role in the pollutants degradation. The CWPO, which followed the Haber-Weiss mechanism, has been accelerated by the Cu and Fe redox cycles. The robustness of the catalyst was verified by negligible amount of metal leaching from the catalysts along with stable catalytic performance after five cycles. Upon the observed results, CuFeO2/Al2O3 with the synergistic effect has shown to be a promising catalyst for removal and degradation of anionic pollutants in CWPO.Decapitation and root pruning, can impact plant morphological and physiological characteristics, which may determine the efficiency of phytoremediation. However, the effects of decapitated and root-pruned plants on the characterization of dissolved organic matter (DOM) and enzymatic activity, which determine the bioavailability of soil pollutants, have rarely been reported. This study aims to characterize DOM and enzymatic activity in the rhizosphere soil of Sedum alfredii when treated by decapitation and root pruning. Decapitation, slight pruning (10% root cutting), and their combination stimulated S. alfredii to secrete more DOM in the rhizosphere soil compared with the control. Furthermore, the proportions of hydrophilic increased from 42.7% in the control to 57.1% in the decapitation and slight pruning combination. Soil urease, invertase, and neutral phosphatase activities were higher in the rhizosphere soil of decapitated and root-pruned S. alfredii, and the highest values were observed with their combination. DOM from the soils of decapitated and root-pruned S. alfredii had significantly higher Cd extraction ability compared with that of the untreated species. Based on the findings of this study, we suggest that decapitation and root pruning can improve the phytoremediation efficiency of S. alfredii by increasing the bioavailability of Cd in its rhizosphere.Nanoencapsulation of biopesticides is an important strategy to increase the efficiency of these compounds, reducing losses and adverse effects on non-target organisms. This study describes the preparation and characterisation of zein nanoparticles containing the botanical compounds limonene and carvacrol, responsive to proteolytic enzymes present in the insects guts. The spherical nanoparticles, prepared by the anti-solvent precipitation method, presented in the nanoparticle tracking analysis (NTA) a concentration of 4.7 × 1012 ± 1.3 × 1011 particles.mL-1 and an average size of 125 ± 2 nm. The formulations showed stability over time, in addition to not being phytotoxic to Phaseolus vulgaris plants. In vivo tests demonstrated that formulations of zein nanoparticles containing botanical compounds showed higher mortality to Spodoptera frugiperda larvae. In addition, the FTIC probe (fluorescein isothiocyanate) showed wide distribution in the larvae midgut, as well as being identified in the feces. The trypsin enzyme, as well as the enzymatic extract from insects midgut, was effective in the degradation of nanoparticles containing the mixture of botanical compounds, significantly reducing the concentration of nanoparticles and the changes in size distribution.