Filtration Of Pollutants Research Articles

Evaluation of Mask Performances in Filtration and Comfort in Fabric Combinations.

A systemic study on improving particulate pollutant filtration efficiency through the combination of conventional fabrics is presented with the objective of finding comfortable, yet effective airway mask materials and products. Fabrics, nonwovens, and their combinations made of cotton, silk, wool, and synthetic fibers are examined on their filtration efficiency for aerosol particles with diameters ranging from 0.225 μm to 3.750 μm under industry-standard testing conditions. It is found that composite fabrics can improve filtration efficiency more than just layers of the same fabric, and the filtration quality factor of some of the fabric combinations can exceed that of the standard melt-blown materials. In addition, fabric friction and charging between the combined layers also improve filtration efficiency substantially. With a broader understanding of the fabric characteristics, we may design mask products with reduced facial skin discomfort, better aesthetics, as well as the ability to alleviate the environmental impact of discarded protective masks in the extended period of controlling the transmission of pollutants and viruses, such as during the COVID-19 pandemic.

Application of Electrospun Water-Soluble Synthetic Polymers for Multifunctional Air Filters and Face Masks.

The worsening of air quality is an urgent human health issue of modern society. The outbreak of COVID-19 has made the improvement of air quality even more imperative, both for the general achievement of major health gains and to reduce the critical factors in the transmission of airborne diseases. Thus, the development of solutions for the filtration of airborne pollutants is pivotal. Electrospinning has gained wide attention as an effective fabrication technique for preparing ultrafine fibers which are specifically tailored for air filtration. Nevertheless, the utilization of harmful organic solvents is the major barrier for the large-scale applicability of electrospinning. The use of water-soluble synthetic polymers has attracted increasing attention as a 'green' solution in electrospinning. We reported an overview of the last five years of the scientific literature on the use of water-soluble synthetic polymers for the fabrication of multifunctional air filters layers. Most of recent studies have focused on polyvinyl alcohol (PVA). Various modifications of electrospun polymers have been also described. The use of water-soluble synthetic polymers can contribute to the scalability of electrospinning and pave the way to innovative applications. Further studies will be required to fully harness the potentiality of these 'greener' electrospinning processes.

Next-generation graphene oxide additives composite membranes for emerging organic micropollutants removal: Separation, adsorption and degradation

In the past two decades, membrane technology has attracted considerable interest as a viable and promising method for water purification. Emerging organic micropollutants (EOMPs) in wastewater have trace, persistent, highly variable quantities and types, develop hazardous intermediates and are diffusible. These primary issues affect EOMPs polluted wastewater on an industrial scale differently than in a lab, challenging membranes-based EOMP removal. Graphene oxide (GO) promises state-of-the-art membrane synthesis technologies and use in EOMPs removal systems due to its superior physicochemical, mechanical, and electrical qualities and high oxygen content. This critical review highlights the recent advancements in the synthesis of next-generation GO membranes with diverse membrane substrates such as ceramic, polyethersulfone (PES), and polyvinylidene fluoride (PVDF). The EOMPs removal efficiencies of GO membranes in filtration, adsorption (incorporated with metal, nanomaterial in biodegradable polymer and biomimetic membranes), and degradation (in catalytic, photo-Fenton, photocatalytic and electrocatalytic membranes) and corresponding removal mechanisms of different EOMPs are also depicted. GO-assisted water treatment strategies were further assessed by various influencing factors, including applied water flow mode and membrane properties (e.g., permeability, hydrophily, mechanical stability, and fouling). GO additive membranes showed better permeability, hydrophilicity, high water flux, and fouling resistance than pristine membranes. Likewise, degradation combined with filtration is two times more effective than alone, while crossflow mode improves the photocatalytic degradation performance of the system. GO integration in polymer membranes enhances their stability, facilitates photocatalytic processes, and gravity-driven GO membranes enable filtration of pollutants at low pressure, making membrane filtration more inexpensive. However, simultaneous removal of multiple contaminants with contrasting characteristics and variable efficiencies in different systems demands further optimization in GO-mediated membranes. This review concludes with identifying future critical research directions to promote research for determining the GO-assisted OMPs removal membrane technology nexus and maximizing this technique for industrial application.

High contribution from outdoor air to personal exposure and potential inhaled dose of PM2.5 for indoor-active university students

People spend most of their time indoors, isolated from the outdoor environment where serious air pollution usually occurs. To what extent outdoor air pollution contributes to their daily personal exposure and inhaled dose? To fill this knowledge gap, an exposure assessment study was conducted for indoor-active university students during a wintertime period of hazy and non-hazy (clear) days in Beijing. Indoor and outdoor fine particulate matter (PM2.5) samples were collected at six indoor microenvironments, and two outdoor environments representing traffic and ambient exposure in the university, respectively, to estimate the personal exposure of students. The average daily personal exposure and poteantial inhaled dose on hazy days (124.8 ± 72.3 μg m−3 and 2.74 ± 1.53 mg) were much higher than that on clear days (57.5 ± 31.9 μg m−3 and 1.26 ± 0.59 mg), indicating a significant influence from the ambient air quality. The indoor PM2.5 concentrations were significantly and positively correlated with the outdoor ones (r = 0.67–0.96) with an FINF (infiltration factor) range of 0.44–0.81 during sampling periods. The outdoor-origin air contributed 68%–95% to the total indoor PM2.5, the average of which was higher during haze events (87%) than clear periods (73%). Correspondingly, outdoor-origin PM2.5 contributed around 105.4 μg m−3 and 2.41 mg (85% and 89%) to the daily exposure and inhaled dose of college students on hazy days, respectively, compared to just 39.2 μg m−3 and 0.95 mg (68% and 75%) on clear days. Our results highlight the significant contribution of outdoor-origin PM2.5 occurred indoor to both the daily personal exposure and inhaled dose due to air pollution filtration between outdoor and indoor environments. These also suggest a continuous effort not only on ambient air quality improvements, but also on environmental friendly building for public health protection with lower exposure.

Use of geostatistical models to evaluate landscape and stream network controls on post‐fire stream nitrate concentrations

AbstractForested watersheds provide many ecosystem services, such as the filtration of sediment, pollutants, and nutrients, which are increasingly threatened by wildfire. For example, stream nutrient concentrations often increase following wildfire and can remain elevated for decades, making downstream waters susceptible to eutrophication. We investigated the drivers of persistent elevated stream nutrients, specifically nitrate (NO3−), in nine watersheds that were burned 16 years prior by the Hayman fire, Colorado, USA. We evaluated the ability of multiple linear regression and spatial stream network modeling approaches to predict observed concentrations of the biologically active solute NO3− and the conservative solute sodium (Na+) which serves as a partial control. Specifically, we quantified the degree to which landscape and stream network characteristics predict stream solute concentrations. Stream Na+ exhibited strong spatial autocorrelation that was primarily controlled by topography and hydrology. In contrast, stream NO3− had higher spatial variability and was inversely correlated to vegetation cover, measured as mean normalized differenced moisture index (NDMI). Spatially heterogeneous wildfire behaviour left intact forest patches interspersed with high burn severity patches dominated by shrubs and grasses which contributes to the spatial variability in stream NO3− concentrations. Post‐fire vegetation also interacts with watershed structure to influence stream NO3− patterns. For example, severely burned convergent hillslopes in headwaters positions were associated with the highest stream NO3− concentrations due to the high proportional influence of hillslope water in these locations. Our findings suggest that targeted reforestation in severely burned convergent hillslopes in headwater positions may enhance the recovery of stream NO3− concentrations to pre‐fire levels.

Air pollution abatement by selective nanoparticle deposition on filtration systems

Air pollution kills an estimated seven million people worldwide every year. The data from the World Health Organization (WHO) shows that almost all the global population (99%) breathe air that exceeds WHO guideline limits. The growing population and urbanization such as in Africa, which has the fastest growing population, may lead to substantial worsening of the air quality. Urbanization is also a powerful driver of the epidemiologic transition from traditional threats like infectious diseases and malnutrition to chronic, non-communicable diseases. Particulate matter less than 2.5 microns in size, PM2.5, is the leading contributor to air pollution which results in such diseases like chronic obstructive pulmonary disease (COPD), bronchitis, and lung cancer. Recent studies have shown a strong correlation between ambient air pollution and COVID-19 cases, which has affected the lives of billions of people around the world. Abatement technologies such as ionic and other high efficiency filtration systems are quite expensive and hence unaffordable to communities with limited resources. The goal of this study was to develop an air pollution filtration method utilizing selective nanoparticle deposition in optimized concentrations, to maximize the entrapment of PM2.5 particles. The experimental set-up consisted of a wind tunnel with incense sticks as the PM2.5 source, measured by laser particle detectors upstream and downstream of the filters. Different nanoparticle coated filters were tested using the ‘Design of Experiments’ methodology and it was concluded that an optimized mixture of zinc oxide, titanium dioxide & graphene improved filtration efficiency of a baseline filter by 206% and was 70% cheaper than high efficiency filters. The versatility and cost-effectiveness of this design makes it applicable for personal masks & filters, air-conditioning and car-cabin filters, and fire-fighting equipment. The significant correlation between air pollution and fatalities from viral infections like COVID-19, makes such abatement technologies with innovative filtration systems critical to save human lives.

Influence of the Web Formation of a Basic Layer of Medical Textiles on Their Functionality.

The aim of the present study was to determine the influence of the spunbond process and the meltblown process, as well as various combinations of the two processes, on the functional performance of layered nonwovens for medical purposes. In the present study, eight samples used in the medical field, mainly for medical masks, were analysed. The samples studied were laminated nonwovens produced by the spunbond and meltblown processes, and combinations of spunbond and meltblown processes. In order to determine the influence of the technological process used to produce a base layer of nonwoven fabrics on their functionality, measurements of tensile strength and extension, water vapour permeability, air permeability, porosity, and thermal conductivity were performed. In addition, the structural characteristics of selected samples were analysed, such as fibre diameter, thickness, mass, raw material composition, and surface openness. The aim of the present study was to find the optimal combination of spunbond and meltblown processes for medical textiles. Based on the research results, we can conclude that the five-layer composite in which three layers are made by spunbond (S) and two layers are made by meltblown (M) in combination as SSMMS from PP fibres has optimal air permeability, filtration of pollutants passing through a protective mask, water vapour permeability and thermal conductivity, and is optimal for use as a multilayer nonwoven fabric for medical masks. Multilayer SSMMS composites also have a lower weight, resulting in less energy and time required for recycling such textiles.

Coupled electrochemical transformation and filtration of water pollutants by cathodic-carbon nanotube membranes

This study aimed at evaluating the concomitant electrochemical reduction and separation of organic and inorganic model contaminants from water. A highly conductive (40,000 S/m) support free carbon nanotube (CNT) membrane was used as a cathode in a three-electrode electrochemical crossflow membrane filtration system. Diatrizoate (DTZ), a recalcitrant iodinated contrast media; resazurin (RZ), a redox indicator; and hexavalent chromium ion (Cr(VI)), a ‘gold’ standard for characterization of reducing systems, were tested as model contaminants. Voltages of −0.6 to −1.0 V were enough to remove between 90% and 95% of the three model contaminants tested. Removal of Cr(VI) proceeded by reduction to Cr(III) followed by adsorption onto the cathode, which could be efficiently regenerated (up to 95%) applying reversal (anodic) potential. Preliminary findings applying AC current (0.6–1.5 V, 10 Hz-1 kHz) suggest that it could be a feasible approach for detoxification with minimization of membrane clogging. Resazurin was immediately transformed into resorufin to near completion which was in turn further reduced to dihydroresorufin. The reductive transformation of DTZ resulted in almost complete deiodination, leading to the accumulation of 3,5-diacetamidobenzoic acid as the main end-product. Although other five secondary transformation products were detected, four of them were fully deiodinated. Concluding, the proposed electrochemical filtration cell equipped with a highly conductive CNT-cathodic membrane can be regarded as a potential technique for water decontamination and effective dehalogenation of organic compounds.

Marriage of membrane filtration and sulfate radical-advanced oxidation processes (SR-AOPs) for water purification: Current developments, challenges and prospects

• The combination technology of SR-AOPs and membrane filtration (MF) was summarized. • The current scenario of various integrated catalytic filtration membranes methods was centralized. • SR-AOPs/MF was used to remove pollutants and reduce membrane fouling. • The future opportunities and challenges of this technology are discussed. Integration of membrane filtration (MF) and sulfate radical-advanced oxidation processes (SR-AOPs) has progressively attracted extensive attention for environmental remediation because of simultaneous degradation and filtration of pollutants in wastewater. Current development of the integration of MF and SR-AOPs can be divided into three main categories: (1) peroxymonosulfate (PMS)/peroxydisulfate (PDS) are activated by membrane materials to achieve the purpose of synergistic oxidation-filtration process; (2) removal of contaminants was achieved by filtering through the membrane, and then adding PMS/PDS to regenerate the membrane; (3) the membrane can be directly used as an oxidant-catalyst/water contactor to promote SR-AOPs. On this basis, this review comprehensively summarizes the classification, preparation methods and properties of different types of membrane-based materials and filtration devices. In addition, the antifouling effect and self-purification regeneration ability of different SR-AOPs systems on the membrane are highlighted. Moreover, the main mechanisms including the analysis of active sites, the generation of free radicals, and the theoretical calculations in integration of MF and SR-AOPs are defragmented and discussed. Finally, the technical challenges of coupling technology in wastewater treatment are discussed, and the development and application prospects of the collaborative mixing process are prospected.

Determining Carbon Dioxide Emission Response in Soil Microcosms from a Shallow Mid-Atlantic Peatland: The Influence of Water Table Restoration

Johnson, A.M.; Atkinson, R.B.; Steven, J.C.; Whiting, G.; Napora, K.; Sharrett, L., and Mirda, C., 2022. Determining carbon dioxide emission response in soil microcosms from a shallow mid-Atlantic peatland: The influence of water table restoration. Journal of Coastal Research, 38(2), 261–268. Coconut Creek (Florida), ISSN 0749-0208. Determining carbon dioxide emission response in shallow microcosms from a shallow mid-Atlantic peatland: The influence of water table restoration. Peatlands provide ecosystem services such as pollution filtration, flood control, and carbon storage as these ecosystems contain 33% to 50% of the global soil carbon pool. Reestablishing soil saturation in degraded peatlands can limit microbial oxidation of organic matter; however, drainage history may alter soil saturation patterns and challenge restoration efforts. The purpose of this study was to investigate carbon emission response to water table restoration for two shallow peatlands including a Histosol and an Ultisol with divergent drainage histories. Soil cores were gathered from the top 22.5 cm of organic-rich surface horizons within Cavalier Wildlife Management Area in Chesapeake, Virginia. Cores were randomly assigned to four water level treatments that simulated restoration conditions, and carbon dioxide emissions were measured using an LI-6400XT portable open-flow photosynthesis system twice a week for 4 weeks. Despite higher organic matter content in the long-drained site, emissions (2.1 to 3.9 µmol CO2 m–2 s–1) were higher than at the historically less drained site (1.5 to 2.3 µmol CO2 m–2 s–1). Volumetric water content trends revealed that longer-drained soils retained lower water content within restoration treatments and were associated with higher carbon emissions. Restoration of long-drained peats in the mid-Atlantic region may require higher water tables than otherwise predicted to overcome a resistance to rewetting where limiting microbial soil respiration is a management objective.

Urban greenery for air pollution control: a meta-analysis of current practice, progress, and challenges.

Most governmental initiatives in India, to leash down urban air pollution, have yielded little results till date, largely due to purely technocratic vision, which is shrouded by technological, economic, social, institutional, and political hardships. We present this reflective article on urban greenery, as a proposition to urban authorities (e.g., pollution regulators, environmental systems’ managers, urban landscape planners, environmental policy makers), shift from purely technocratic way of thinking to thinking with nature, by strategic greening of urban spaces, for long-term air pollution prevention and control measures. To that end, we offer a meta-analysis of recent (post 2005) global literature using four-stage PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach. We open the narrative by briefing about main pollutant filtration mechanisms by trees, followed by cognitive aspects of species selection (e.g., deciduous vs. evergreen, air pollution tolerance index, environmental stressors). Till date, most Indian studies on urban greenery mostly but focused on physiological aspects of trees. Here, we draw attention of urban authorities to an equally compelling, but yet less explored, aspect: design criteria, with reference to two most common urban configurations, namely, street canyon and open road. With pictorial depictions, we enumerate various categories of street canyons and discuss aspect ratio (building height to street width) and various wind flow regimes (isolated roughness, wake interface, and skimming), that the urban authorities should be cognizant about to maximize pollutant removal efficiency. For open road, we discuss vegetation barriers, with special emphasis on canopy porosity/density functions. In the final sections, we reflect on a potential systems’ thinking approach for on-ground implementation, comprising of revamping of urban forestry programs, research and development, community mobilization and stakeholder engagement, and strategic outreach. In addition, we emphasize on means to harness co-benefits of urban greenery, beyond mere pollutant removal, to garner support from urban residents’ communities. Last but not the least, we also caution the urban authorities about the undesirable outcomes of urban greenery that will require more process-level research.Supplementary InformationThe online version contains supplementary material available at 10.1007/s10661-022-09808-w.

Sustainable conversion of waste tea biomass into versatile activated carbon: application in quick, continuous, and pressure filtration of miscellaneous pollutants

Sustainable conversion of waste tea biomass into versatile activated carbon: application in quick, continuous, and pressure filtration of miscellaneous pollutants

ВІДНОВЛЕННЯ ДЕГРАДОВАНИХ МІСЬКИХ ВОДНО-БОЛОТНИХ УГІДЬ (НА ПРИКЛАДІ СОВСЬКИХ СТАВКІВ У КИЄВІ)

The article is devoted to the problem of the preservation of urban wetlands as the most vulnerable valuable ecosystems in the conditions of rapid urbanization, which need to be protected. It researches the current state of the Sovky tract (and the lower cas­cade wetlands of the Sovski Ponds located within it) in the center of Kyiv. Despite the strong urban influence, the rich floristic and faunal diversity of the studied area has been revealed. The value of urban wetlands for Kyiv is determined by the vital ecosystem services provided to the local community. Such services include, first of all, regulation of the microclimate, moisture and nutrients distribution in the soil, habitats preservation for the rare species of animals and plants, regulation of the groundwater levels, pollution filtration, waste adsorption, oxygen produc­tion and carbon dioxide absorption, water quality improvement, mitigation of the climate change consequences, creation of the favourable conditions for recreation, etc. As a result of field surveys of the Sovky tract, the complete decline of the territory and the degradation of valuable wetlands have been indicated. We have investigated the main geoecological conflicts caused by littering of the territory with household and construction waste, persistent pollution of the water bodies caused by untreated sewage due to unauthorized intrusions of resi­dents into the household sewers, chemical and noise pollution from the road infrastructure, grass burning in spring, etc. The spatial localisation of all conflicts within the Sovky tract is shown on the relevant map. The negative consequences of the long-term unresolved conflicts for the functioning of the wetlands and the quality of the ecosystem services they provide have been identified. Given the perspective of development in the study area of the ecopark and a fairly general idea of the essence of this concept, we proposed to include wetlands of Sovky tract in the Nature Reserve Fund of Kyiv. According to the current legislation, this area meets all the criteria of the category “Regional Landscape Park” (RLP).The main purpose of preserving the unique urban wetlands is the protection of rare species of plants and animals and their natural habitats, which is possible only in the conditions provided for in the RLP reserved zone. In addition, granting the official status of a protected area will make it impossible to build and litter within unique urban wetlands in the future.

РОЗРОБЛЕННЯ ЗАХОДІВ ДЛЯ ПІДВИЩЕННЯ ЕКОЛОГІЧНОЇ БЕЗПЕКИ ПИТНОГО ВОДОПОСТАЧАННЯ НАСЕЛЕННЯ СХІДНОЇ УКРАЇНИ ЗА РАХУНОК ВИКОРИСТАННЯ ПІДЗЕМНИХ ВОД БУЧАЦЬКО-КАНІВСЬКОГО ВОДОНОСНОГО КОМПЛЕКСУ

In the article, measures to increase the ecological safety of population drinking water supply due to the use of Buchak-Kaniv aquifer groundwater from urban water intakes in Eastern Ukraine have been developed. The ecological consequences of man-made intervention in Buchak-Kaniv aquifer drinking groundwater at the research territory have been assessed. The main pollutant elements of these groundwater have been traced. Water intakes (Poltava, Karlivka, Krasnograd, Lubny, Khorol, Reshetylivka), where the ecological consequences of technogenic intervention in the underground hydrosphere are the greatest, since here the target groundwater is partially or completely unsuitable for drinking purposes, have been identified. The key role of technogenesis (intensification of groundwater withdrawal and expansion of water intakes network; as a result – changes in the hydrodynamic conditions of operational aquifers and formation of their regional depression funnels) in these processes has been established. It is emphasized that the increased content of investigated pollutant elements in systematically consumed drinking water has a colossal effect on the human body, which can be expressed in a number of serious diseases. In the paper, measures have been developed to minimize the established ecological consequences of technogenesis of Buchak-Kaniv aquifer drinking groundwater to increase the ecological safety of population drinking water supply from the Poltava city agglomeration water intakes, which are strategically important for the studied region. The system of groundwater hydrogeochemical monitoring at the region water intakes has been improved for the conditions of filtration of pollutants from the surface or their migration from below in the zones affected by tectonic faults associated with salt diapirs. This significantly shortens the time and reduces the cost of works in comparison with a full complex of hydrogeochemical studies within the entire territory. The allocation of promising areas for the construction of new water intakes to solve the problem of drinking groundwater lack of acceptable quality within the research territory has been substantiated. Estimated resources of high-quality drinking groundwater in a radius of 40 km around the Poltava city, the involvement of which will allow providing high-quality drinking water to the population of this urban agglomeration. The optimal general water withdrawal at the Poltava water intakes to stabilize the content of polluting elements in the composition of Buchak-Kaniv aquifer groundwater within different parts of the city has been justified.

Grazing Effects on the Composition, Diversity, and Function of Wet Meadow Grasslands in Manitoba, Canada

Wet grasslands are an important element of rangeland communities around the world and are key in the provision of many ecosystem services, including interception of runoff, filtration of pollutants, storage of carbon, and maintenance of wildlife habitat. In the northern Great Plains, wet grasslands are often more productive than upland grasslands and are an important source of seasonal forage or hay. As climates continue to limit growing conditions and yields of upland forages, grazing pressure on wet grasslands may increase. Our research focused on a wet meadow rangeland in Manitoba, Canada to test how the timing and intensity of grazing affect the composition, diversity, and function of plants and soils. Our results demonstrate that the effects of grazing on wet meadow grasslands depend on its timing and intensity. Early grazing shifted the composition of plants, increasing the abundance of weedy and invasive species, including foxtail barley (Hordeum jubatum). The effect of grazing on plant diversity also depended on its intensity. As a result, the spatial heterogeneity of wet grasslands increased following early, intense grazing but decreased following late-season grazing. Although the effect of grazing on a number of soil variables did not differ among grazing treatments, early, intense grazing increased soil bulk density. Our results demonstrate that late-season, moderate-intensity grazing can sustain the diversity and function of wet meadow grasslands. Our research also highlights the negative impacts of early-season, intense grazing on the proliferation of weedy and invasive plants. As changing climates across the Great Plains continue to increase grazing pressure on marginal rangelands, adaptive management must focus on increasing the resilience of wet grasslands. Our work points to an important gap in our understanding of interactions among grazing, ecosystem services, and belowground production in wet meadow grasslands.

Green electrospinning of chitin propionate to manufacture nanofiber mats

Chitin is the second most abundant biopolymer after cellulose in nature, and it is currently under-utilized partially because of its insolubility in common solvents. Herein, chitin was propionylated to improve its dissolution in green solvents, i.e., ethanol and water, and manufactured nanofibers and nonwoven mats via electrospinning with poly(ethylene oxide) (PEO) as a co-spinning aid. Polymer solution viscosity, electrospun CP/PEO fiber morphology, mechanical, thermal, dynamic thermal, and surface contact angle of nanofiber mats were evaluated. Results showed that fibers with CP content up to 97% could be produced. The electrospun CP/PEO nanofiber mats exhibited good mechanical strength, thermal stability, and hydrophobicity with water contact angles up to 133°. Filtration test of separating carbon nanofibers and carbon nanotubes from water demonstrated the potential use of the CP/PEO nanofiber mats in fluid filtration of fibrous pollutants.

Modelling Flow and Fate of Contaminants in Groundwater Using a Version of the Five Steady- State Pollutant Transport Models

It is essential to understand pollutant flow and fate in the permeation zones for adequate groundwater quality protection. This review highlights the hydraulic controls on pollutant filtration into the groundwater. The study is divided into seven sections, viz: Numerical modelling of contaminants in aquifers; Modeling tool for pollutant flow, fate, and theorisation; Theoretical approaches to groundwater modelling; Model input variables; and Modeling the vertical flow of contaminants from surface water to aquifers; Recent advances; and Challenges of groundwater pollution modelling. The latter illustrates how contaminants flow are simulated in a saturated aquitard aquifer. Model Type 2 is applied to simulate contaminant flow in a fully splintered formation. Model Type 3 showed the vertical flow of contaminants within an unsaturated zone. The vertical flow of pollutants within an unsaturated region without a recharge is simulated using Model Type 4. Model Type 5 is applied to study gas-phase flow from a point situated within the un-inundated area beneath a confined zone, to the uppermost layer of the superimposed groundwater reservoir and then flow horizontally into the aquifer. Application of these models shows that an initial measurement with traditional, and repeatedly selecting none-site-specific factor. The models are qualitatively harmonious in conjunction with general trends in interpretations and offer a convenient approximation of pollution. However, the execution of these models is limited by a lack of adequate field data. Thus, the model output must be examined within the model uncertainty framework, data input limitations, and methodologically established standards from the literature.

High flux and complete dyes removal from water by reduced graphene oxide laminate on Poly Vinylidene Fluoride/graphene oxide membranes

Dyes molecules are the most common pollutants of wastewater in the environment from the textile industry to numbers of technologies include dyeing, printing, and painting procedures. Among membrane-based separation approaches as established methods in the water treatment industry, polymers attracted massive attention in the production of membranes due to their low cost and high-performance filtration of pollutants. However, hydrophobicity and low speed of filtration along with limited decontamination performance against some of the dyes, demand new approaches and membranes to overcome drawbacks points. Herein, a new design introduced including a support layer made by Poly Vinylidene Fluoride (PVDF)/Graphene Oxide (PGO) composite membrane via immersion precipitation process and a thin layer (≤100 nm) of reduced graphene oxide (rGO) deposited (as an active layer) through a simple vacuum filtration method. It has been observed that the presence of the GO sheets in the PGO composite improved the hydrophilicity of the membrane, water flux (from ~90 L m−2 h−1 bar−1 in pristine PVDF to ~1690 L m−2 h−1 bar−1 in PGO), and anti-fouling property. By deposition of rGO laminate on PGO support, dyes separation as high as ~99% can be achieved for most of the cationic and anionic dyes due to electrostatic adsorption, π−π interactions and molecular sieving. This approach opens new insight on hybrid designs for graphene-polymers based membrane toward efficient and fast removal of pollutants from wastewater.

A change model of the hydraulic characteristics of the territory occupied by the landfill of solid industrial and domestic waste

Introduction. A landfill of solid industrial and domestic waste (LSIDW) is a source of negative impact on the environment. Although landfills have coverings, and they are equipped with engineering systems designated for the capturing and treatment of the biogas, LSIDW landfills still have a negative impact on subsurface and surface waters due to the spread of leachate. The purpose of this work is to obtain predictive data on changes in the hydrogeological characteristics of the territory of Salaryevo landfill, and to develop a simulation model to assess the application of technical solutions in the course of the landfill reclamation.
 Materials and methods. Processing Modflow is the software designated for the 3D modeling of filtration and transportation of pollutants. An engineering report based on the engineering and environmental surveys, performed by JSC MosvodokanalNIIproekt in the Salaryevo landfill and its environs in 2017, served as the input data designated for a simulation model.
 Results. Processing Modflow software allowed to consider three options of cutoff walls, tailored to this landfill. The installation of cutoff walls on the east and west sides of the landfill, to be performed with regard for the sorption function of the cutoff walls, is the most effective solution. The results have shown that the cutoff walls, installed to prevent the leachate from seeping, can potentially reduce the area, exposed to the impact, by 500 m.
 Conclusions. It is recommended to install a cutoff wall in the west and a sorption curtain in the east in the course of recultivating Salaryevo landfill; this solution will ensure the containment of the leachate inside the landfill and prevent its spreading.

2D confinement freestanding graphene oxide composite membranes with enriched oxygen vacancies for enhanced organic contaminants removal via peroxymonosulfate activation

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.