Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 8.835
Filtrar
1.
J Colloid Interface Sci ; 630(Pt A): 795-803, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36279838

RESUMO

Ion-selective membrane is the key component for osmotic energy conversion. Nanofluid channels based on two-dimensional materials have advantages of facile preparation, tunable channel size, and easy upscaling, which is promising for efficient osmotic energy harvesting. However, further improvement of the output power is hindered by the low ion sensitivity for the limited charge density. Herein, we demonstrate the preparation of a cation-selective polydopamine-coated graphene oxide composite membrane with the sandwich structure by a simple interfacial polymerization technique, which greatly improves the surface charge density and further generates a power density of 3.4 W/m2 under river water and seawater. The GO membrane is firstly fabricated to function as the supporting layer and provide the reaction sites. And the ultrathin selective layer of the polydopamine membrane is chemically bonded with the GO layer by the in-situ polymerization on both sides of the GO membrane. The sandwiched nanofluidic membrane with ultrahigh charge density exhibits both high cation selectivity and ionic conductivity, benefiting the performance of osmotic energy conversion. The economic, easy-prepared method of the sandwiched nanofluidic membrane provides a promising strategy for high-performance osmotic energy conversion.


Assuntos
Grafite , Polímeros , Osmose , Polímeros/química , Grafite/química , Íons/química
2.
Chemosphere ; 310: 136910, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36270524

RESUMO

Reverse osmosis (RO) membrane has been widely used in various water treatment fields as an efficient desalination technology, but serious biofouling problem arises in the actual application process. Curcumin is known as a natural compound that can reduce biofouling by inhibiting the growth of microorganisms based on quorum sensing. Dopamine, a molecule with excellent adhesion and functionalization on the material's surface, has high research value for applying a curcumin coating to the membrane surface. Curcumin degrades under alkaline conditions, whereas dopamine must polymerize under alkaline conditions. Simultaneously, a coating may adversely affect curcumin. Therefore, a two-step coating process was considered by self-polymerizing dopamine on the thin-film composite membrane surface and then dip-coating curcumin attached to the polydopamine layer. Furthermore, the effect of time and concentration on the surface modification before and after membrane modification was investigated. The highest permeability of 1.39 L/m2/hr/bar was achieved with the modified membranes. The number of gram-positive bacteria decreased from 6.71 × 106 to 9.67 × 105 CFU/mL. This result is meaningful for antifouling through modification of the membrane surface. Use of curcumin can be applied to reduce biofouling and extend the lifetime of the membrane without pretreatment or membrane cleaning.


Assuntos
Incrustação Biológica , Curcumina , Purificação da Água , Incrustação Biológica/prevenção & controle , Curcumina/farmacologia , Osmose , Membranas Artificiais , Dopamina
3.
Sci Total Environ ; 856(Pt 2): 159196, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36198350

RESUMO

Membrane efficiency coefficient of clay is evaluated with considering the effect of fixed charges adsorbed on clay mineral surfaces. By virtue of the concept of chemical potential, the ionic concentration of pore water is calculated. An equation is first proposed to calculate the Donnan osmotic pressure based on the activity of water (H2O), and then a new method is developed to determine the membrane efficiency coefficient, based on the theoretical chemo-osmotic pressure difference. The proposed method is used to calculate the membrane efficiency coefficients of geosynthetic clay liners (GCLs) with different bentonite contents and porosities under different KCl concentrations. The calculated results are compared to those of van't Hoff equation, showing that if skeletal deformation is excluded, the proposed model and van't Hoff equation with average ion concentration difference yield practically the same results; if the deformation is considered, however, van't Hoff equation yields smaller membrane coefficients.


Assuntos
Bentonita , Água , Argila , Osmose , Pressão Osmótica
4.
Chemosphere ; 311(Pt 1): 136906, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36270521

RESUMO

Microplastics (MPs) are emerging contaminants that are abundantly present in the influent and effluent of wastewater treatment plants (WWTPs). Forward osmosis (FO) is an advanced treatment technology with potential applications in WWTPs. The presence of MPs in WWTP effluents can contribute to FO fouling and performance deterioration. This study focuses on FO membrane fouling by MPs of different sizes, and the interactional impacts of MPs and Humic acid (HA) (as the most common organic foulant in WWTPs) on FO membrane performance. The synergistic effect of combined MPs and HA fouling is shown to cause higher flux decline for FO membranes than that of HA or MPs alone. Reverse salt flux increased in the presence of MPs, and decreased when HA was present. Further, full flux recovery was obtained for all fouled membranes after hydraulic cleaning. This indicates the efficiency of FO systems for treating wastewater with high fouling potential. This study highlights the necessity of considering MPs in studying fouling behaviour, and for mitigation strategies of membranes used in WWT. The fundamentals created here can be further extended to other membrane-assisted separation processes.


Assuntos
Microplásticos , Purificação da Água , Plásticos , Membranas Artificiais , Osmose , Águas Residuárias , Substâncias Húmicas
5.
Food Microbiol ; 109: 104146, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36309445

RESUMO

Ultrafiltration (UF) and reverse osmosis (RO) are commonly used for the clarification and concentration of fruit juices. However, one of the main limitations of filtration membranes is biofouling, which reduces membrane efficiency and can contaminate the filtered product and lead to spoilage. In this study, the microbial fouling layers of UF and RO membranes from a Canadian cranberry juice processing plant were characterized. Unlike the microbiota found in cranberry juice, which is dominated by Bacillus sp. and other bacteria, both UF and RO membranes were mainly colonized by several strains of the yeast Candida krusei. A variation in bacterial and yeasts count was observed between tubular UF and spiral-wound RO membranes, and the analysis of the spatial distribution highlighted the homogeneity of the contamination across each membrane. Surprisingly, RO membranes had a higher level of contamination when compared to UF membranes. Furthermore, six strains of C. krusei were further characterized through multilocus sequence typing analysis, five of which exhibited unique allelic profiles and two of which were found to contain a new TRP1 allele.


Assuntos
Ultrafiltração , Vaccinium macrocarpon , Osmose , Membranas Artificiais , Canadá , Filtração , Bactérias
6.
Food Chem ; 399: 133972, 2023 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-36027810

RESUMO

Pomegranate (Punica grantum L.) fruit juice was concentrated by forward osmosis or thermal evaporation and the samples were stored at ambient (25 °C) and accelerated (37 °C) storage conditions. The anthocyanin content of raw, reconstituted forward osmosis as well as reconstituted thermally evaporated pomegranate juice were 421.1, 414.4 and 357.2 mg/kg respectively. The physicochemical attributes of pomegranate juice concentrate such as anthocyanin content, antioxidant activity, browning index, and hydroxymethyl furfural showed that the quality of the concentrate was markedly affected by storage conditions. Based on the hydroxymethyl furfural content (≤25 mg/kg), it was concluded that the forward osmosis concentrated juices could be stored at ambient and accelerated conditions for ∼101 and ∼66 days, respectively. While, thermally concentrated juice could only be stored for less ∼31 and ∼3 days, respectively. Forward osmosis could be a method to concentrate pomegranate juice with minimum effect on quality attributes with extended shelf life.


Assuntos
Sucos de Frutas e Vegetais , Romã (Fruta) , Antocianinas/análise , Frutas/química , Furaldeído/análise , Cinética , Osmose
7.
Water Environ Res ; 94(11): e10802, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36333995

RESUMO

Microbial fuel cells (MFCs) and forward osmosis (FO) are both attractive and versatile wastewater treatment technologies that possess disadvantageous qualities that prevent their optimal performance. This study aimed to investigate how draw solute selection for FO treatment would affect MFC performance in a coupled FO-MFC system. Two types of draw solutes, NH4 HCO3 and NaCl, were studied, and it was found that 1.0 M NH4 HCO3 (FO-MFC-A) and 0.68 M NaCl (FO-MFC-B) had similar water fluxes of 6.04 to 3.39 LMH and 6.25 to 3.54 LMH, respectively. The reverse salt flux from the draw decreased the feed solution resistance for both draw solutes, but the FO-MFC-A system (0.32 W m-2 ) had a higher maximum power density than the FO-MFC-B system (0.26 W m-2 ). The current density for the FO-MFC-B system increased due to continuous solution resistance decrease, whereas it remained constant for the FO-MFC-A. The difference in Coulombic efficiencies (32.8% vs. 25.6%) but similar Coulombic recoveries (10.2% vs. 11.4%) between the FO-MFC-A and FO-MFC-B systems suggested that the FO-MFC-A might have the inhibited microbial activity by high ammonium/ammonia. The FO-MFC-A system had the lower energy consumption for nutrient removal (2.01 kWh kg-1 NH4 + -N) and recovery (8.87 kWh kg-1 NH4 + -N). These results have shown that NH4 HCO3 as a draw solute can have advantages of higher power density, higher Coulombic efficiency, and recoverability for draw regeneration, but its potential inhibition on microbial activity must also be considered. PRACTITIONER POINTS: Forward osmosis can be connected to microbial fuel cells for wastewater treatment. Water recovery by forward osmosis can greatly reduce the wastewater volume to microbial fuel cells. Ammonium draw solutes can result in lower volumetric energy consumption. Ammonia inhabitation of anode microbes will decrease organic removal.


Assuntos
Compostos de Amônio , Fontes de Energia Bioelétrica , Purificação da Água , Águas Residuárias , Amônia , Cloreto de Sódio , Membranas Artificiais , Osmose , Purificação da Água/métodos , Água
8.
Int J Mol Sci ; 23(21)2022 Oct 24.
Artigo em Inglês | MEDLINE | ID: mdl-36361569

RESUMO

Using the previously developed cell model of a charged membrane and the principles of linear thermodynamics of irreversible processes (the Onsager approach), exact and approximate (in the case of an ideally selective membrane) analytical formulae for calculating the osmotic and electroosmotic permeability of the membrane in aqueous solutions of 1:1 electrolyte at constant electric current density and concentration gradient were suggested. The formulae have been successfully verified by our own experimental data for the extrusion cation-exchange membrane MF-4SC p.29 in NaCl solution up to concentrations of 3 M. The contribution of electroosmotic and osmotic water fluxes to the total water transport through the mentioned individual perfluorinated ion-exchange membrane under conditions close to the process of electrodialysis concentrating was experimentally estimated. The cases of co- and counter-directed osmotic and electroosmotic water fluxes are studied. A good correspondence between theoretical and experimental results was obtained, which made it possible to determine the physicochemical parameters of the electromembrane system (the diffusion coefficients of individual ions and the coefficient of equilibrium distribution of electrolyte molecules in the membrane matrix, the characteristic exchange capacity of the cell model). The achieved results make it possible to fully characterize existing and promising types of ion-exchange membranes based on the developed cell model of a charged membrane.


Assuntos
Eletrólitos , Água , Água/química , Osmose , Eletrólitos/química , Cátions , Membranas
9.
Water Sci Technol ; 86(9): 2213-2232, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36378176

RESUMO

Dissemination of multiresistant bacteria and high concentrations of micropollutants by hospitals and other medical facilities can be significantly reduced by a wide variety of on-site treatment approaches. Membrane filtration technologies, ranging from microfiltration to reverse osmosis, have been adapted in many studies and offer multiple purposes in advanced wastewater treatment configurations. While the direct rejection of pharmaceutical compounds and pathogens can only be achieved with nanofiltration and reverse osmosis processes, porous membranes are known for their pathogen removal capabilities and can be used in combination with other advanced treatment approaches, such as oxidation and adsorption processes. This review was conducted to systematically assess studies with membrane filtration technologies that are used as either stand-alone or hybrid systems for the treatment of hospital wastewater. In this review, four different databases were screened with a pre-set of search strings to thoroughly investigate the application of membrane filtration technology in hospital wastewater treatment. Hybrid systems that combine multiple treatment technologies seem to be the most promising way of consistently removing micropollutants and pathogens from hospital wastewater, but additional economic assessments are needed for an extensive evaluation.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Águas Residuárias , Osmose , Filtração , Membranas Artificiais , Hospitais , Eliminação de Resíduos Líquidos
10.
Water Res ; 225: 119130, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-36240724

RESUMO

Organic micropollutants (OMPs) in drinking water constitute a potential risk to human health; therefore, effective removal of these pollutants is required. Nanofiltration (NF) and reverse osmosis (RO) are promising membrane-based technologies to remove OMPs. In NF and RO, the rejection of OMPs depends on the properties and characteristics of the membrane, the solute, and the solution. In this review, we discuss how these properties can be included in models to study and predict the rejection of OMPs. Initially, an OMP classification is proposed to capture the relevant properties of 58 OMPs. Following the methodology described in this study, more and new OMPs can be easily included in this classification. The classification aims to increase the comprehension and mechanistic understanding of OMP removal. Based on the physicochemical principles used to classify the 58 OMPs, it is expected that other OMPs in the same groups will be similarly rejected. From this classification, we present an overview of the rejection mechanisms involved in the removal of specific OMP groups. For instance, we discuss the removal of OMPs classified as perfluoroalkyl substances (e.g., perfluorooctanoic acid, PFOA). These substances are highly relevant due to their human toxicity at extremely low concentration as well as their persistence and omnipresence in the environment. Finally, we discuss how the rejection of OMPs can be predicted by describing both the membrane-solution interface and calculating the transport of solutes inside the membrane. We illustrate the importance and impact of different rejection mechanisms and interfacial phenomena on OMP removal and propose an extended Nernst-Plank equation to calculate the transport of solutes across the membrane due to convection, diffusion, and electromigration. Finally, we show how the theory discussed in this review leads to improved predictions of OMP rejection by the membranes.


Assuntos
Água Potável , Poluentes Ambientais , Fluorcarbonetos , Poluentes Químicos da Água , Purificação da Água , Humanos , Purificação da Água/métodos , Osmose , Filtração/métodos , Membranas Artificiais , Soluções , Poluentes Químicos da Água/análise
11.
Ren Fail ; 44(1): 1595-1603, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36190833

RESUMO

BACKGROUND: Aluminum accumulation is a well-described complication in dialysis patients. Improvements in hemodialysis technology have possibly eliminated the occurrence of aluminum overload. Limited evidence suggests that aluminum overload may decline in the era of aluminum removal from dialysis fluids, even with the use of aluminum binders. METHODS: We examined the data from January 2014 to June 1, 2020, identified through our electronic records, to evaluate the desferrioxamine (DFO) test results for aluminum overload. The presentation and treatment of aluminum overload were recorded. RESULTS: Ninety-nine dialysis patients were enrolled for the DFO test. Forty-seven patients (47.5%) were identified as DFO test positive for aluminum overload, of which 14 (14/47) patients had symptoms, including one patient with an unexplained fracture, eight patients with unexplained anemia despite high-dose erythropoiesis-stimulating agents, and five patients with hypercalcemia (serum calcium >11 mg dL-1). None of the patients with aluminum overload developed encephalopathy. Only four of the 47 patients had microcytic anemia. Patients requiring longer treatments (>10 months versus <10 months) had similar basal serum aluminum (p = 0.219) but had an increase in serum aluminum after DFO (p = 0.041). Furthermore, the treatments decreased erythropoietin doses in the aluminum overload group, with serum total alkaline phosphatase levels <60 U L-1 (p = 0.028). CONCLUSION: We concluded that aluminum overload existed in the reverse osmosis dialysis era. In light of non-obvious symptoms, such as anemia and bone turnover change, serum aluminum in dialysis patients should be monitored in countries using aluminum-based phosphate binders, despite reverse osmosis dialysis.


Assuntos
Anemia , Eritropoetina , Fosfatase Alcalina , Alumínio/efeitos adversos , Compostos de Alumínio , Anemia/tratamento farmacológico , Cálcio , Desferroxamina/uso terapêutico , Humanos , Osmose , Fosfatos , Diálise Renal/efeitos adversos
12.
Sci Rep ; 12(1): 16636, 2022 Oct 05.
Artigo em Inglês | MEDLINE | ID: mdl-36198707

RESUMO

In regions with limited potable water availability, membrane desalination is being employed to filter water using a pressure-driven approach. Because of the high energy consumption required to produce the pressure differential needed for this method, researchers have been trying different geometric designs of spacer filaments to enhance the amount of permeate flux in terms of energy utilization. The purpose of spacer filaments is to support membranes structurally and induce turbulent mixing in spiral wound membrane desalination. In this paper, the improvement of mass transfer in desalination driven by reverse osmosis has been studied using Computational Fluid Dynamics (CFD) with the introduction of spiral wound membranes that are lined with spacer filaments in a zig-zag formation having alternating diameters for strands. The fluid flow characteristics for a 2-dimensional geometric model were resolved using the open-source program OpenFOAM by changing the Reynolds number to just before the inception of instabilities. Ratios of alternate strand diameters were also varied between one and two. Based on a detailed analysis of velocity contours, pressure distribution, wall shear stresses, and steady-state vortex systems, the research findings offer guidance for employing alternating strand design in zig-zag formation for optimum mass transfer and minimal pressure drop when accounting for concentration polarization.


Assuntos
Incrustação Biológica , Água Potável , Purificação da Água , Membranas Artificiais , Osmose , Purificação da Água/métodos
13.
Water Sci Technol ; 86(7): 1629-1641, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36240300

RESUMO

Coking wastewater has a complex and highly concentrated chemical composition which is toxic and does not biodegrade easily. Treating the organic pollutants in this wastewater is very challenging. The toxic substances in this wastewater make traditional biotechnological treatments inefficient. Current wastewater treatment studies are based on unit processes, and no full process studies could be found. This study used the micro-nanometer catalytic ozonation process as a pretreatment unit, and reverse osmosis membrane treatment as a depth processing unit to improve the effect of the coking wastewater degradation. The micro-nanometer catalytic ozonation pretreatment greatly improves the biodegradability of the coking wastewater and promotes the coking wastewater degradation in the anoxia/anaerobic/oxic (A/A/O) system. The integrated coagulation air flotation-micro-nanometer catalytic ozonation-A/A/O-reverse osmosis membrane system can remove 98% of the chemical oxygen demand, which meets the direct emission standard of the new national standard (China). The dominant genera in the A/A/O biochemical reactor were Thioalkalimicrobium, Proteiniphilum, Azoarcu, Bacillus, Fontibacter, and Taibaiella. This work provides a novel approach for the degradation of high-concentration organic wastewater and lays a solid foundation for the restoration of environmental water bodies.


Assuntos
Coque , Poluentes Ambientais , Ozônio , Poluentes Químicos da Água , Coque/análise , Humanos , Hipóxia , Osmose , Ozônio/química , Eliminação de Resíduos Líquidos , Águas Residuárias/química , Água , Poluentes Químicos da Água/análise
14.
Int J Mol Sci ; 23(19)2022 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-36233037

RESUMO

Recently, there has been a special research focus on the bioconversion of glycerol to 1,3-propanediol (1,3-PD) due to its significance in the chemical industry. However, the treatment and separation of fermentation broths is a great challenge. Currently, the reverse osmosis (RO) process is a reliable state-of-the-art technique for separation of biological solutions. This study (as the first to do so) investigated the feasibility of separation of 1,3-PD broths with the use of cellulose acetate (CA) membrane by the RO process. The experiments were carried out using the installation equipped with the plate module, under the transmembrane pressure (TMP) and temperature of 1 MPa and 298 K, respectively. It was found that the used membrane was suitable for broth separation. Indeed, it was noted that 1,3-PD, as a target product, migrated through the membrane; meanwhile, other broth components were rejected in various degrees. Moreover, it was proven that retention of carboxylic acids tended to increase with increasing molecular weight, according to the following order: succinic acid > lactic acid > acetic acid > formic acid. With regards to ions, retention degree increased with the increase of ionic radius and decrease of diffusion coefficient. Finally, it was demonstrated that the CA membrane is resistant to irreversible fouling, which has a positive effect on the economic viability of the process.


Assuntos
Membranas Artificiais , Purificação da Água , Ácidos Carboxílicos , Celulose/análogos & derivados , Estudos de Viabilidade , Fermentação , Formiatos , Glicerol , Ácido Láctico , Osmose , Succinatos , Purificação da Água/métodos
15.
Biofouling ; 38(8): 852-864, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36314078

RESUMO

The decline in the performance of spiral-wound reverse osmosis (SWRO) membranes is frequently due to biofouling. This study focus on qualitative and quantitative diagnosis of SWRO membrane biofouling. Bacterial counts on the different surfaces of the fouled membranes were carried out. Surface enhanced Raman spectroscopy (SERS) was performed to highlight clogging materials as well as their natures and identity. The topography of the fouled membranes and the structures of biofilms were visualized by fluorescence microscopy (FM) and scanning electron microscopy (SEM). The results indicated the presence of bacteria in the different SWRO membrane areas. Those strongly adhered were significantly higher than those weakly. It varied between 26 × 105 and 262 × 105 CFU m-2. However, SERS mapping showed different fouling levels and the thickness of the fouling layer was 5 µm. Microscopic imaging revealed biotic and abiotic deposits. These data can together allow better management of the seawater desalination process.


Assuntos
Incrustação Biológica , Purificação da Água , Osmose , Análise Espectral Raman , Purificação da Água/métodos , Biofilmes , Membranas Artificiais
16.
Water Res ; 226: 119221, 2022 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-36242936

RESUMO

The challenge of water scarcity drives zero liquid discharge (ZLD) treatment to maximize reuse of industrial wastewater. Deciphering the characteristics and mechanisms of membrane fouling in the membrane-based ZLD system is crucial for the development of effective fouling control strategies. However, current studies only focused on the membrane fouling of single step, lacking in-depth understanding on the ZLD systems using multiple membrane processes. Herein, membrane fouling characteristics and mechanisms in a full-scale ZLD system for cold-rolling wastewater brine treatment were investigated via a comprehensive analysis on multiple nanofiltration (NF) and reverse osmosis (RO) membrane processes. The membrane fouling behaviors showed distinct characteristics along the wastewater flow direction in the ZLD system. Increasing amounts of foulants were deposited on the membrane surfaces with the sequence of the 1st pass RO, 1st stage NF, and 2nd stage NF processes. The organic fouling and silica scaling were more intensive in the 1st stage NF and 2nd stage NF for treating the brine of the 1st pass RO, as the foulants were rejected and concentrated by previous membrane processes. Severe inorganic fouling, containing amorphous SiO2, Al2O3, and Al2SiO5, occurred on the membrane surface of the 2nd pass RO membrane, due to the recirculated high-concentration silica, high water recovery, and concentration polarization. For the 3rd pass RO process, both the amounts of organic and inorganic foulants decreased dramatically, due to the low foulant concentration in its influent. This work provides a comprehensive understanding of membrane fouling in a membrane-based ZLD system, facilitating the development of membrane fouling control strategies for multiple membrane processes.


Assuntos
Águas Residuárias , Purificação da Água , Osmose , Membranas Artificiais , Dióxido de Silício
17.
Water Sci Technol ; 86(8): 1904-1914, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36315084

RESUMO

Urine is a major source of reclaimed water and fertilizer. Urine treatment involves two key processes: the recovery of nutrients and the rejection of trace organic compounds (TOrCs). In this study, we investigated the rejection of TOrCs and the recovery of nutrients in human urine using a seawater-driven forward osmosis and membrane distillation (FO-MD) hybrid system. Three 24 h experiments were conducted at draw solution temperatures of 30, 40, and 50 °C. The average rejection rates of cations, anions, and dissolved organic carbon were more than 93.7% and 79.5% in the FO-MD system and FO side, respectively. Ten types of TOrCs were detected in the feed solution, whereas none were detected in the product water, indicating that the TOrCs were completely rejected. The precipitates, i.e., the recovered nutrients in the FO side, were extremely close to magnesium ammonium phosphate (struvite, MgNH4PO4·6H2O), according to their electron microscopic images, elemental composition, and X-ray diffraction spectra, and it was estimated that approximately 85% of the nutrients in the feed solution were recovered. The rejection and recovery efficiencies were unaffected by the draw solution temperature. These results indicate the potential for the sustainable use of FO-MD-based treatments for human urine.


Assuntos
Destilação , Purificação da Água , Humanos , Destilação/métodos , Purificação da Água/métodos , Membranas Artificiais , Osmose , Compostos Orgânicos , Águas Residuárias , Água , Nutrientes
18.
Chemosphere ; 309(Pt 1): 136618, 2022 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-36181845

RESUMO

With dam failure events, there can be changes in water quality and difficulties in the operation of water treatment plants (WTPs) since they were not designed for water treatment under severe pollution conditions. To avoid that, it was investigated two strategies based on pre-oxidation, ultrafiltration (UF) and reverse osmosis (RO) integrated into a conventional treatment process (coagulation, flocculation, and sand filtration) or with each other, with the potential to reduce the risks of drinking water shortage and guarantee a safe drinking water supply. The study considered the context of the Velhas river basin (Brazil), where water quality is compromised by high turbidities (500-3000 NTU) and excessive arsenic (∼0.4 mg/L), iron (∼50 mg/L), and manganese (∼3 mg/L) levels. They were only partially removed by conventional treatments (removals: 74 ± 21%) and potability standards were only achieved after the membrane separation processes were considered (As: <0.01 mg/L, Mn: <0.1 mg/L, and Fe: <0.3 mg/L). The high water quality after RO enables its blend with the stream obtained after sand filters and would allow for greater flexibility during the operation of WTPs operation. Despite the susceptibility to fouling and most frequent maintenance, the pre-oxidation-UF-RO system would also guarantee a safe drinking water supply. The decision for the most adequate strategy was then based on a multicriteria analysis. A retrofit of conventional WTPs by their integration with UF-RO was classified as the best strategy for centralized facilities, whereas pre-oxidation-UF-RO better fits the reality of decentralized treatments given the lower costs and deployment time. The methodology based on multicriteria analysis and water treatment technologies, exemplified by membranes in this study, presented satisfactory results for different scenarios of critical treatment.


Assuntos
Arsênio , Água Potável , Purificação da Água , Osmose , Membranas Artificiais , Manganês , Ultrafiltração/métodos , Filtração/métodos , Purificação da Água/métodos , Tecnologia , Ferro
19.
J Food Sci ; 87(11): 4839-4853, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36250503

RESUMO

Pulsed electric field (PEF) and osmotic dehydration (OD) pretreatment can accelerate the time-consuming drying process and minimize its high energy demands. The effect of PEF and OD pre-processing conditions and osmotic solution composition on mass transfer kinetics (water loss, solid gain, water activity) and quality properties (color, texture, total sensory quality) during OD and subsequent air-drying (AD) of pumpkin was studied. Application of PEF (2.0 kV/cm-1500 pulses) significantly enhanced mass transfer during subsequent air-drying (increased effective diffusivity coefficient Des and drying rate kdrying , respectively). PEF and OD treatments led to a significant reduction of the processing time by 12 and 10%, respectively (p < 0.05). The maximum reduction of processing time by 27% (p < 0.05) (compared to untreated sample) resulted in combined use of PEF and OD as pretreatments prior to AD. When PEF pretreatment was combined with OD prior to AD, the corresponding energy was by 50% less than the respective energy required for nonprocessed samples. PRACTICAL APPLICATION: Pulsed electric fields (PEF) and osmotic dehydration (OD) can be applied for the production of air-dried pumpkin cuts of superior quality (in terms of quality and sensory characteristics) and reduced energy requirements (as a result of total processing time decrease).


Assuntos
Cucurbita , Desidratação , Osmose , Dessecação/métodos , Água
20.
Artigo em Inglês | MEDLINE | ID: mdl-36078275

RESUMO

In dental clinics, the infections may be acquired through contaminated devices, air, and water. Aerosolized water may contain bacteria, grown into the biofilm of dental unit waterlines (DUWLs). We evaluated a disinfection method based on water osmosis and chlorination with chlorine dioxide (O-CD), applied to DUWL of five dental clinics. Municipal water was chlorinated with O-CD device before feeding all DUWLs. Samplings were performed on water/air samples in order to research total microbial counts at 22-37 °C, Pseudomonas aeruginosa, Legionella spp., and chlorine values. Water was collected from the taps, spittoons, and air/water syringes. Air was sampled before, during, and after 15 min of aerosolizing procedure. Legionella and P. aeruginosa resulted as absent in all water samples, which presented total microbial counts almost always at 0 CFU/mL. Mean values of total chlorine ranged from 0.18-0.23 mg/L. Air samples resulted as free from Legionella spp. and Pseudomonas aeruginosa. Total microbial counts decreased from the pre-aerosolizing (mean 2.1 × 102 CFU/m3) to the post-aerosolizing samples (mean 1.5 × 10 CFU/m3), while chlorine values increased from 0 to 0.06 mg/L. O-CD resulted as effective against the biofilm formation in DUWLs. The presence of residual activity of chlorine dioxide also allowed the bacteria reduction from air, at least at one meter from the aerosolizing source.


Assuntos
Desinfecção , Legionella , Bactérias , Biofilmes , Cloro/farmacologia , Compostos Clorados , Contagem de Colônia Microbiana , Equipamentos Odontológicos , Desinfecção/métodos , Contaminação de Equipamentos/prevenção & controle , Osmose , Óxidos , Pseudomonas aeruginosa , Água , Microbiologia da Água
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...