Bartonhirsch8680

Toxicity assessment of the products in the process of ozone degradation showed that toxicity of the products was reduced by benzene ring cleavage and a reduction in the F atomic number. However, the toxicity of nitro and brominated products of BPAF was increased. These findings provide some new insights into the role of common ions in ozonation process and product formation, and supplement the existing conclusions. check details The results of this study remind future researchers to concern that inorganic ions in real water may be converted into corresponding free radicals that affect the formation of ozone oxidation products.Contamination by microplastics (MP) represents a critical environmental challenge with potential consequences at ecosystem, economic and societal levels. As the marine system is the final sink for MP, there is an urgent need to develop methods for the monitoring of synthetic particles in different marine compartments and sample matrices. Extensive evaluations are hindered by time and costs associated with to conventional MP spectroscopic analyses. The potential of near infrared hyperspectral imaging (NIR-HSI) has been recently evaluated. However, NIR-HSI has been poorly studied so far, limitedly to the detection of large particles (>300 μm), and its capability for direct characterization of MP in real marine matrices has not been considered yet. In the present study, a rapid near infrared hyperspectral imaging (NIR-HSI) method, coupled with a customised normalised difference image (NDI) strategy for data processing, is presented and used to detect MP down to 50 μm in environmental matrices. The proposed method is largely automated, without the need for extensive data processing, and enabled a successful identification of different polymers, both in surface water and mussel soft tissue samples, as well as on real field samples with environmentally occurring MP. NIR-HSI is applied directly on filters, without the need for particles pre-sorting or multiple sample purifications, avoiding time consuming procedures, airborne contaminations, particle degradation and loss. Thanks to the time and cost effectiveness, a large-scale implementation of this method would enable to extensively monitor the MP presence in natural environments for assessing the ecological risk related to MP contamination.The development in urbanization, growth in industrialization and deficiency in crude oil wealth has made to focus more for the renewable and also sustainable spotless energy resources. In the past two decades, the concepts of microbial fuel cell have caught more considerations among the scientific societies for the probability of converting, organic waste materials into bio-energy using microorganisms catalyzed anode, and enzymatic/microbial/abiotic/biotic cathode electro-chemical reactions. The added benefit with MFCs technology for waste water treatment is numerous bio-centered processes are available such as sulfate removal, denitrification, nitrification, removal of chemical oxygen demand and biological oxygen demand and heavy metals removal can be performed in the same MFC designed systems. The various factors intricate in MFC concepts in the direction of bioenergy production consists of maximum coulombic efficiency, power density and also the rate of removal of chemical oxygen demand which calculates the efficacy of the MFC unit. Even though the efficacy of MFCs in bioenergy production was initially quietly low, therefore to overcome these issues few modifications are incorporated in design and components of the MFC units, thereby functioning of the MFC unit have improvised the rate of bioenergy production to a substantial level by this means empowering application of MFC technology in numerous sectors including carbon capture, bio-hydrogen production, bioremediation, biosensors, desalination, and wastewater treatment. The present article reviews about the microbial community, types of substrates and information about the several designs of MFCs in an endeavor to get the better of practical difficulties of the MFC technology.Anaerobic digestion technology has been widely used because it has a unique advantage of producing biogas as a renewable energy source. Therefore, several methods were studied to facilitate anaerobic methane production process. Coupling direct voltage and single conductive particles was an effective method to improve anaerobic wastewater treatment efficiency and methane production. However, the enhancement method was limited in this process due to the current of direct voltage or the toxicity of nanoparticles. Therefore, the granular activated carbon loaded with nanoscale zero valent iron (GAC-NZVI) particles prepared by co-precipitation method were added to the anaerobic synthetic wastewater system with direct voltage (0.10 V) to improve the treatment efficiency in this study. GAC-NZVI particles were added into anaerobic system with 0.10 V direct voltage to enhance CH4 production process. The COD removal and total CH4 production were enhanced by 4.22 % and 10.83 % with GAC-NZVI particles. The measurement results of EPS and Fe concentration showed that GAC-NZVI particles promoted the secretion of EPS by microorganisms, which could improve the floc strength of granular sludge. The measurements of conductivity and cyclic voltammetry (CV) showed that particles accelerated the metabolism of microorganism and promoted the electron transfer process. The increasing of Methanothrix and Methanobacterium could strengthen the methanogenesis. The abundances of bacteria and archaea using indirect interspecies electron exchange form (such as H2 or formate transfer microorganisms) were decreased after adding the particles. The results indicated that anaerobic treatment efficiency could be enhanced under the combined action of direct voltage and particles.The presence of highly toxic and persistent pesticides in water bodies causes serious problems to human beings as well as aquatic life. Quinalphos is one such widely used organophosphorus pesticide in agricultural fields. Herein, for degradation and mineralization of quinalphos, ZnO nanoflowers and their hybrid nanocomposite with graphene oxide have been synthesized. FESEM analysis confirmed the formation of ZnO nanoflowers over nanosheets of graphene oxide having a thickness of 20 ± 10 nm. GO-ZnO composite exhibited remarkable photocatalytic activity in comparison to pure ZnO. 98 % degradation of quinalphos was achieved using GO-ZnO nano-catalyst at 6 pH within 45 min of irradiations, whereas it was 80 % for bare ZnO nanoflowers. Higher degradation with hybrid nanocomposite was attributed to improved surface area (36 m2 g-1), a substantial reduction in bandgap energy from 3.10 to 2.90 eV and enhanced charge separation (e-/h+ pairs) after the addition of GO. Reaction kinetics study followed pseudo-first-order behaviour. Further, mineralization to the extent of 90 % in 90 min was confirmed by TOC analysis. Based on identified intermediates, using LCMS analysis, degradation pathways were proposed. The plausible pathways confirmed the presence of smaller and safer reaction intermediates supported by excitation of e- from nanocomposite followed by oxidation of quinalphos with huge free radicals. Overall, this study is significant in terms of using photocatalysis as a tertiary treatment of quinalphos pesticide wastewater at pH 6 in a short duration.Vast efforts are directed today toward the development of efficient, green methods for the degradation of toxic compounds, especially those that are water-soluble. Though Fenton reactions are commonly used in wastewater treatment, their mechanisms and the active species involved remain obscure due to their mechanistic complexity. In this work, the mechanism of an electro-Fenton reaction, in which a FeLaO3 catalyst was entrapped in a sol-gel matrix, was studied in the presence of azo dyes as the model for toxic compounds. Increased knowledge about this important mechanism will confer greater control over related processes and enable a more efficient and green degradation method. DFT calculations showed that in the presence of Fe(IV), OH are formed under acidic conditions and that both the iron and hydroxyl species function as oxidation reagents in the degradation process. The structure of the formed Fe(IV) embedded in the solid matrix was not the typical tetravalent structure. Entrapment in the sol-gel matrix stabilized the catalyst, enhanced its efficiency and enabled it to be recycled. Sol-gel matrices constitute a simple method for the degradation of stable and toxic compounds under extreme pH conditions. The findings of this study are highly significant for the treatment of typically acidic wastewaters.Quantifying methylmercury (MeHg) concentrations and uptake at the base of the food web is useful for assessing mercury exposure risk to higher trophic level organisms. Higher MeHg concentrations near the base of the food web may result in more MeHg exposure and accumulation in higher trophic organisms. Here, we analyze MeHg in caddisflies, mayflies, lake water, and sediment collected from two temperate lakes and one brook in Kejimkujik National Park, Nova Scotia, Canada. Overall, caddisfly larvae MeHg (15.38-276.96 ng/g; n = 29) was not significantly correlated with water chemistry. Whereas mayfly naiads MeHg (14.28-166.82 ng/g; n = 31) was positively correlated with water MeHg (rs = 0.43), negatively correlated with pH (rs = -0.49), and positively correlated with dissolved organic carbon (DOC; rs = 0.48). Of the mercury in insect tissues, the %MeHg ranged from 56 to 75 % in caddisfly larvae and 38-47 % in mayfly naiads. MeHg bioaccumulation factors (BAF) varied greatly (water to tissue BAFs = 0.145 × 106-1.054 × 106; sediment to tissue BAFs = 0.017 × 106-0.541 × 106). This study highlights the importance of quantifying variations in MeHg bioaccumulation and BAFs of common aquatic insect bioindicators at the base of complex food webs.The problem of deep oxidation of low concentrations of VOCs in industrial tail gas is exceptionally urgent. The preparation of VOCs ozonation catalyst with a high mineralization rate is still a challenge. In this paper, manganese oxide carriers with different morphologies were synthesized by simple methods and used to catalyze ozone mineralization of toluene after loading Pt nanoparticles efficiently. The conversion of toluene over Pt/MnOx-T catalyst was more than 98 % at ambient temperature, and the mineralization rate of toluene was close to 100 % at 70 °C. Through a variety of characterization methods, the strong metal-support interaction (SMSI) between Pt nanoparticles and carriers was successfully constructed. It was found that SMSI successfully optimized the surface oxygen species and oxygen migration ability of the catalyst, and then realized the high degree of mineralization of toluene at low temperature. This paper guides the subsequent development of Pt-Mn catalysts for catalytic organic pollutants ozonation with high activity.The complexity of natural water made it difficult to remove fluoride. Based on the environmental problems found in the investigation, the fluoride removal research in the water containing algal cells was carried out. In this study, AlCl3 and [AlO4Al12(OH)24(H2O)12]7+ (Al13) were used to remove fluoride. Additionally, the role of aluminum speciation in fluoride removal and the effect of Microcystis aeruginosa on the fluoride removal by different aluminum species coagulants were elucidated. The results showed that AlCl3 mainly removed fluoride by physical interactions, surface adsorption and enmeshment. When algal cells were added to the system, the fluoride removal rate increased from 22.75 % to 72.99 % at a dosage of 40.0 mg/L. This was because algal cells greatly increased the distribution of Al(OH)3 in the flocs. In particular, the specific surface area of the flocs containing algal cells reached 160.77 m2/g, which allowed more fluoride to be adsorbed. However, excessive Al3+ led to serious damage to algal cells and release of intracellular organic matter (IOM), worsening the effect of defluoridation.