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1.
Water Res ; 168: 115157, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614235

RESUMO

Hemodialysis is one of the therapies for patients with kidney failure. Hemodialysis requires large amounts of pure water, and is one of the most water-hungry medical procedures, and thus represents a clear opportunity where improvements should be made concerning the consumption and wastage of water. In this paper, we explored the potential of forward osmosis (FO) membrane for recycling the spent dialysate using the dialysis concentrate as the draw solution. Partially diluted dialysis concentrate could be further diluted with pure water to form dialysate for further dialysis process. Using commercial cellulose triacetate (CTA) FO membranes, the water recovery of approximately 64% was achieved and the final volume of the partially diluted dialysis concentrate was about four times the initial volume. Flux decline of the FO process was observed, mainly due to concentration of synthetic spent dialysate and dilution of dialysis concentrate, while membrane scaling had little impact on the flux decline. The urea rejection was found to be relatively low owing to the small size and electroneutral nature of the urea molecule. Obvious membrane scaling was observed after three FO cycles. The energy dispersive spectroscopy analysis of the scaling layer indicated that the scalants were phosphates and carbonates. The scaling was removed via osmotic backwash and almost completely recovery of FO flux was obtained. Economic analysis showed that the centralized treatment of spent dialysate in a dialysis center using the proposed osmotic dilution process could greatly save water resources and cost. Improving the urea rejection of FO membrane was identified as an important research focus for future research on the potential application of FO technology for recycling the spent dialysate in hemodialysis.


Assuntos
Purificação da Água , Análise Custo-Benefício , Soluções para Diálise , Estudos de Viabilidade , Membranas Artificiais , Osmose
2.
Water Res ; 168: 115105, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31614236

RESUMO

The high content of organics in municipal reverse osmosis concentrate (ROC) requires proper treatment. Here, this study applied the photoelectrocatalysis (PEC) to reduce the concentration of organics in ROC. Meanwhile, the formation of disinfection byproducts (DBPs) was investigated. Participation of primary oxidants in organics removal and DBPs formation was revealed at different anodic potentials and pHs. The results showed that PEC process effectively oxidized the organics in ROC, achieving the highest mineralization rate of 63%. Increasing anodic potential from 0 to 1.0 V enhanced the oxidations of bulk organics (i.e., dissolved organic carbons (DOC), UV254, fluorescence, large molecular weight compounds) and trace-level pharmaceuticals. Raising anodic potential to higher than 1.0 V slightly benefited the oxidations of bulk organics, owing to the relatively stable formation of hydroxyl radicals (OH•) and radical reactive chlorine species (r-RCS). The continuously rising concentration of free chlorine (FC) accelerated the decompositions of pharmaceuticals at ≥ 1.0 V. However, the generated FC raised the concentration of DBPs up to 10.36 µmol/L at 3.0 V. Lowering initial pH from 7-9 to 4-6 improved the mineralization rates by around 20% due to the higher formation of OH• at pH 4-6. Further decreasing initial pH from 6 to 4 enhanced the breakdown of large molecular weight compounds as well as the decomposition of pharmaceuticals. This came from the strengthened formation of FC and r-RCS at lower pHs. The intense participation of FC and r-RCS resulted in a higher total DBP concentration at pH 4-6 than that at pH 7-9. However, the individual species of DBPs changed differently toward the pH shift. The results of this study show that PEC could be an alternative for organics oxidation in ROC with proper control of DBPs formation.


Assuntos
Poluentes Químicos da Água , Purificação da Água , Cloro , Desinfecção , Halogenação , Osmose
3.
Water Res ; 168: 115135, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31622911

RESUMO

Silica fouling during groundwater reverse osmosis (RO) treatment can have a significant impact on filtration performance. To better understand this phenomenon, the equilibrium kinetics of amorphous colloidal silica were studied at conditions relevant to RO of silica-rich alkaline groundwater. The impact of particle size was investigated using synthetic monodisperse silica nanoparticles. Bench scale experiments were conducted by monitoring dissolved silica concentration of aqueous suspensions of colloids of 100 and 300 nm diameter and pH 8.5 to 9.5. The equilibrium data was determined from existing established rate law equations. This study concluded that surface energy has a major impact on silica dissolution rate constant, particularly for colloidal silica. Observations of Ostwald ripening in bidisperse silica dispersions further confirmed these results, which indicate that dissolution and redeposition is responsible for the problematic silica fouling behaviour during RO treatment. 2D modelling based on inferred equilibrium data allows visualization of scale layer growth in agreement with cross-sectional scanning electron micrographs of autopsied membranes.


Assuntos
Água Subterrânea , Purificação da Água , Coloides , Estudos Transversais , Membranas Artificiais , Osmose , Rádio (Anatomia) , Dióxido de Silício , Solubilidade
4.
Water Res ; 168: 115198, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31654961

RESUMO

The biofouling potential of three isolated dissolved organic fractions from seawater according to their molecular weights (MWs), namely, fractions of biopolymers (F.BP, MW > 1000 Da), humic substances and building blocks (F.HS&BB, MW 350-1000 Da), and low molecular weight compounds (F.LMW, MW < 350 Da) were characterized by assimilable organic carbon (AOC) content. The AOC/DOC ratio was in the order of F.LMW (∼35%) > F.BP (∼19%) > F.HS&BB (∼8%); AOC/DOC of seawater was ∼20%; organic compositions of seawater were BP ∼6%, HS&BB ∼52% and LMW ∼42%; LMW accounted for >70% of AOC in seawater. Their impact on SWRO biofouling in term of flux decline rate was in the order of F. LMW (∼30%) > F.BP (∼20%) > F.HS&BB (<10%). Despite being the major organic compound in seawater, HS&BB showed marginal effect on biofouling. The role of indigenous BP was less critical owing to its relatively low concentration. LMW, which was the major AOC contributor, played a significant role in biofouling by promoting microbial growth that contributed to the build-up of soluble microbial products and exopolymeric substances (i.e., in particular BP). Therefore, seawater pretreatment shall focus on the removal of AOC (i.e., LMW) rather than the removal of biopolymer.


Assuntos
Incrustação Biológica , Purificação da Água , Membranas Artificiais , Osmose , Água do Mar
5.
Water Environ Res ; 91(10): 1350-1377, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31529571

RESUMO

The review scans research articles published in 2018 on physico-chemical processes for water and wastewater treatment. The paper includes eight sections, that is, membrane technology, granular filtration, flotation, adsorption, coagulation/flocculation, capacitive deionization, ion exchange, and oxidation. The membrane technology section further divides into six parts, including microfiltration, ultrafiltration, nanofiltration, reverse osmosis/forward osmosis, and membrane distillation. PRACTITIONER POINTS: Totally 266 articles on water and wastewater treatment have been scanned; The review is sectioned into 8 major parts;  Membrane technology has drawn the widest attention from the research community.


Assuntos
Purificação da Água , Fenômenos Químicos , Filtração , Floculação , Membranas Artificiais , Osmose , Eliminação de Resíduos Líquidos , Águas Residuárias
6.
J Environ Manage ; 251: 109524, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31542619

RESUMO

The presence of excess fluoride in aqueous media above local environmental standards (e.g., the U.S. Environmental Protection Agency (EPA) standard of 4 mg/L) affects the health of aquatic life. Excess fluoride in drinking water above the maximum contaminant level (e.g., the World Health Organization (WHO) standard of 1.5 mg/L) also affects the skeletal and nervous systems of humans. Fluoride removal from aqueous solutions is difficult using conventional electrochemical, precipitation, and adsorption methods owing to its ionic size and reactivity. Thus, new technologies have been introduced to reduce the fluoride concentration in industrial wastewater effluents and various drinking water sources. Membrane technology is one of the newer technologies found to be very effective in significantly reducing fluoride to desired standards levels; however, it has received less attention than other technologies because it is perceived as a costly process. This study critically reviewed the performance of various membrane process and compared it with effluent and zero liquid discharge (ZLD) standards. The performance review has been conducted with the consideration of the theoretical background, rejection mechanisms, technical viability, and parameters affecting flux and rejection performance. This review includes membrane systems investigated for the defluoridation process but operated under pressure (i.e., reverse osmosis [RO] and nanofiltration [NF]), temperature gradients (i.e., membrane distillation [MD]), electrical potential gradients (i.e., electrodialysis [ED] and Donnan dialysis [DD]), and concentration differences (i.e., forward osmosis [FO]). Moreover, the study also addressed the advantages, limitations, & applicable conditions of each membrane based defluoridation process.


Assuntos
Águas Residuárias , Purificação da Água , Fluoretos , Membranas Artificiais , Osmose , Água
7.
J Environ Manage ; 250: 109487, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31545175

RESUMO

The feasibility of wellhead water treatment in small communities for nitrate removal and salinity reduction via a flexible high recovery RO system was evaluated through analysis of treatment options, laboratory and onsite field tests. In small remote communities that rely on septic systems for residential wastewater treatment, discharge of the RO residual stream (containing nitrate) to the community septic tank is shown to be a feasible option. It is demonstrated that RO treatment with a system that employs partial concentrate recycle, integrated with a pressure intensifier, enabled the use of a relatively low-pressure feed pump while allowing high recovery operation. The approach of integrating RO treatment into existing community small water systems is demonstrated to be suitable for providing effective nitrate removal and salinity reduction over wide range of nitrate and salinity levels, while meeting community water demand and regulatory water quality requirements.


Assuntos
Salinidade , Purificação da Água , Estudos de Viabilidade , Osmose , Eliminação de Resíduos Líquidos , Águas Residuárias
8.
J Environ Manage ; 249: 109382, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31421481

RESUMO

Textile industry generates a high volume of wastewater containing various type of pollutants. Although high color and chemical oxygen demand (COD) removals are achieved with the combination of biological and chemical treatment processes, reverse osmosis (RO) process is generally needed for water recovery due to high conductivity of the textile wastewater. In this study, a pilot scale RO process containing one spiral wound membrane element was operated under three different operational modes, i.e. concentrated, complete recycle and continuous, to collect more information for the prediction of a real-scale RO process performance. It was claimed that complete recycle mode of operation enabled mimicking the operational conditions exerted on the first membrane, whereas continuous mode of operation created conditions very similar to the ones exerted on the last membrane element in a real scale RO process train. In the concentrated and continuous mode of operation, water recovery and flux were around 70% and 19 L/m2/h (LMH). Permeate produced in the RO process can be safely reused in the dyeing process as the feed and permeate conductivities were around 5500 µS/cm and 150 µS/cm, respectively, at 70% water recovery. However, color concentration in the concentrate exceeded the discharge limits and would need further treatment. The RO performance was accurately predicted by ROSA simulations.


Assuntos
Águas Residuárias , Purificação da Água , Membranas Artificiais , Osmose , Têxteis , Eliminação de Resíduos Líquidos , Água
9.
J Environ Manage ; 249: 109394, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31434051

RESUMO

The forward osmosis (FO) membrane process has recently established in many applications such as desalination, wastewater reuse, water purification, food processing, resource recovery and sustainable power generation. However, many researchers raise the demand for systematic investigation on FO membrane fouling, which leads to reduced flux yield. In this study, the effect of coagulation/persulfate as a feed pre-treatment was used to mitigate FO organic fouling during municipal wastewater treatment, and compared with a control coagulation and potassium persulfate pre-treatments. Mass balance results using size exclusion chromatography exhibited that the decrease in the flux with consecutive filtration cycles was likely due to humic-like molecules in the feedwater. Coagulation/persulfate contributed to a more significant flux improvement than stand-alone coagulation or persulfate pre-treatment, resulting in a smaller amount of organics attachment to the membrane. A better flux enhancement by coagulation/persulfate was again evidenced by a higher decrease in the attachment of reversible and irreversible organic foulants on the membrane surface. This study identified the major organic components responsible for FO fouling and established the potential of coagulation/persulfate pre-treatment for reducing organic fouling of FO membrane during municipal wastewater treatment.


Assuntos
Águas Residuárias , Purificação da Água , Filtração , Membranas Artificiais , Osmose
10.
Niger J Clin Pract ; 22(8): 1166-1168, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31417063

RESUMO

Osmotic demyelination syndrome (ODS) is a life-threatening neurological condition often associated with rapid correction of hyponatremia. While ODS is thought to be rare, with prevalence rates of not more than 0.5% in autopsy series, mortality rates are as high as 90% in some studies. Thus, timely diagnosis and life-saving treatment rest on a high index of suspicion among clinicians. In this report, we discuss the case and literature review of a 45-year-old female with sepsis, acute kidney injury, and spontaneous hypernatremia who developed ODS but responded to therapy with high dose steroids, antibiotics, and supportive care.


Assuntos
Lesão Renal Aguda/complicações , Doenças Desmielinizantes/etiologia , Hipernatremia/complicações , Hiponatremia/complicações , Osmose , Encéfalo/diagnóstico por imagem , Doenças Desmielinizantes/metabolismo , Feminino , Humanos , Hipernatremia/metabolismo , Hiponatremia/sangue , Imagem por Ressonância Magnética , Pessoa de Meia-Idade , Mielinólise Central da Ponte/etiologia , Sódio/sangue , Síndrome
11.
Bioresour Technol ; 290: 121795, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31326216

RESUMO

Increasing research and development works have been made to develop forward osmosis (FO) processes as a cost-effective substitute for energy intensive water vacuum suction facility in submerged membrane bioreactor (MBR) applications. Perceived to be a spontaneous water driven process without external applied pressures, the FO has been applied in lab and pilot scales for wastewater bioremediation. This paper reviewed the state-of-the-art developments on the FO unit, the process, and ways of enhancing process performance, particularly on the aspects of flux enhancement, flow resistance reduction, and draw solute with low reverse salt diffusion, which are relevant to enhanced osmotic MBR performance. The perspective to realize the use of FO processes in revision of currently existing energy intensive osmotic MBR processes is discussed with research needs being highlighted.


Assuntos
Águas Residuárias , Purificação da Água , Biodegradação Ambiental , Membranas Artificiais , Osmose
12.
J Food Sci ; 84(8): 2199-2208, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31313316

RESUMO

Bioactive anthocyanins from aqueous extracts of muscadine grape pomace were concentrated using osmotic distillation (OD) and direct contact membrane distillation (DCMD) using polypropylene (PP) and poly(ethylene chlorotrifluoroethylene) (ECTFE) membranes. The driving force for OD is created by using a high concentration brine solution while the driving force for DCMD is generated by elevating the feed temperature relative to the permeate temperature. The brine concentration used was 4 M. The lowest fluxes were obtained for OD. Given the temperature sensitive nature of anthocyanins, the maximum temperature difference during DCMD was limited to 30 °C. The feed temperature was 40 °C and the permeate at 10 °C. Consequently, the maximum flux during DCMD was also limited. A combination of OD and DCMD was found to give the highest fluxes. High-performance liquid chromatography (HPLC) and HPLC-electrospray mass spectrometry were used to identify and quantify anthocyanins, cyanidin-3,5-O-diglucoside, delphinidin-3,5-O-diglucoside, petunidin-3,5-O-diglucoside, peonidin-3,5-O-diglucoside, and malvidin-3,5-O-diglucoside. The results obtained here suggest that, though water fluxes for DI water feed streams for PP and ECTFE membrane were similar, the fluxes obtained for the two membranes when using muscadine pomace extracts were different. Concentration factors of close to 3 was obtained for anthocyanins. Membranes also showed slightly different performance in the concentration process. Membrane surfaces were analyzed using scanning electron microscopy and Fourier-transformed infrared spectroscopy. The results suggest that adsorption of these anthocyanins on the membrane surface lead to performance differences. In an actual operation, selection of an appropriate membrane and regeneration of the membrane will be important for optimized performance. PRACTICAL APPLICATIONS: Anthocyanins are valuable therapeutic compounds, which are found in the solid residue left following fruit juice pressing. However, recovery and concentration of these therapeutic compounds remains challenging due to their stability. Here, a novel membrane-based unit operation has been investigated in order to concentrate the anthocyanins that have been extracted into aqueous solutions. The unit operation investigated here use mild processing conditions. Insights into the factors that need to be considered when optimizing of the unit operation for commercialization are discussed.


Assuntos
Antocianinas/isolamento & purificação , Destilação/métodos , Manipulação de Alimentos/métodos , Extratos Vegetais/isolamento & purificação , Vitis/química , Resíduos/análise , Adsorção , Antocianinas/análise , Cromatografia Líquida de Alta Pressão , Destilação/instrumentação , Manipulação de Alimentos/instrumentação , Sucos de Frutas e Vegetais/análise , Espectrometria de Massas , Osmose , Extratos Vegetais/análise , Temperatura Ambiente
13.
J Sci Food Agric ; 99(14): 6572-6581, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31325328

RESUMO

BACKGROUND: As a pretreatment before drying, the purpose of osmotic dehydration (OD) is to reduce the initial water content of samples and shorten the drying time. When OD is combined with pulse vacuum, the mass transfer is enhanced. Furthermore, the properties of materials, which affect the absorption and dissipation of microwaves, can be changed by OD. In this work, pulsed vacuum osmotic dehydration (PVOD) with sucrose solution was adopted before microwave freeze-drying (MFD). The effects of PVOD on the drying characteristics and quality of dried products were studied. RESULTS: Results showed that the unfrozen water content was increased by PVOD, which made the dielectric constant and loss factor of Chinese yam larger than that of untreated samples, and the difference amplified with the increasing temperature. Thus, the shortened drying time (up to 38.5%) and increased average drying rate (up to 16.8%) were achieved by MFD combined with PVOD. While in traditional freeze-drying, PVOD resulted in slightly shortened drying time but decreased drying rate. The mechanism of PVOD on improving drying rate of MFD was analyzed from the perspective of unfrozen water content and dielectric properties. Furthermore, the quality assessments indicated that PVOD treatment retained a better color and improved the total phenolic content of dried yams compared to untreated and dried samples. CONCLUSION: PVOD using sucrose solution was an effective method to change the characteristics of yam, enhancing the MFD rate and improving the product qualities. © 2019 Society of Chemical Industry.


Assuntos
Dessecação/métodos , Dioscorea/química , Conservação de Alimentos/métodos , Tubérculos/química , Água/análise , Cor , Dessecação/instrumentação , Conservação de Alimentos/instrumentação , Liofilização , Micro-Ondas , Osmose , Fenóis/análise
14.
Food Chem ; 299: 125122, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31288165

RESUMO

To ease the mass exchange in fruit tissues, cutting and blanching are traditionally performed. However, recently, unconventional methods such as sonication are becoming more popular, which cause several alterations of physical and chemical properties as well as microstructure changes. The aim of this work was to evaluate the distribution of water inside the cranberry fruits, microstructural changes and sugars content, following traditional and sonication pre-treatments in osmotic solutions. TD-NMR spectroscopy was used to measure the transverse relaxation time (T2) and intensity of proton pools in different cellular compartments. The microstructure of the samples was evaluated by SEM microscopy, sugars content by HPLC and sucrose melting temperature and enthalpy by DSC. Different pre-treatments appeared to promote microstructure alterations and loss of water from vacuole and cytoplasm/extracellular space, more pronounced in cut and blanched samples. Cutting and blanching followed by osmotic dehydration with assisted sonication eased sucrose penetration into the tissue.


Assuntos
Conservação de Alimentos/métodos , Frutas/química , Açúcares/análise , Vaccinium macrocarpon/química , Água/metabolismo , Varredura Diferencial de Calorimetria , Dessecação , Frutas/ultraestrutura , Espectroscopia de Ressonância Magnética , Microscopia Eletrônica de Varredura , Osmose , Sonicação , Sacarose/análise , Temperatura Ambiente , Vaccinium macrocarpon/ultraestrutura
15.
J Environ Manage ; 248: 109240, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31310933

RESUMO

We systematically investigated the transport mechanisms of organic micropollutants (OMPs) in a fertilizer-drawn forward osmosis (FDFO) membrane process. Four representative OMPs, i.e., atenolol, atrazine, primidone, and caffeine, were chosen for their different molecular weights and structural characteristics. All the FDFO experiments were conducted with the membrane active layer on the feed solution (FS) side using three different fertilizer draw solutions (DS): potassium chloride (KCl), monoammonium phosphate (MAP), and diammonium phosphate (DAP) due to their different properties (i.e., osmotic pressure, diffusivity, viscosity and solution pH). Using KCl as the DS resulted in both the highest water flux and the highest reverse solute flux (RSF), while MAP and DAP resulted in similar water fluxes with varying RSF. The pH of the FS increased with DAP as the DS due to the reverse diffusion of NH4+ ions from the DS toward the FS, while for MAP and DAP DS, the pH of the FS was not impacted. The OMPs transport behavior (OMPs flux) was evaluated and compared with a simulated OMPs flux obtained via the pore-hindrance transport model to identify the effects of the OMPs structural properties. When MAP was used as DS, the OMPs flux was dominantly influenced by the physicochemical properties (i.e., hydrophobicity and surface charge). Those OMPs with positive charge and more hydrophobic, exhibited higher forward OMP fluxes. With DAP as the DS, the more hydrated FO membrane (caused by increased pH) as well as the enhanced RSF hindered OMPs transport through the FO membrane. With KCl as DS, the structural properties of the OMPs were dominant factors in the OMPs flux, however the higher RSF of the KCl draw solute may likely hamper the OMPs transport through the membrane especially those with higher MW (e.g., atenolol). The pore-hindrance model can be instrumental in understanding the effects of the hydrodynamic properties and the surface properties on the OMPs transport behaviors.


Assuntos
Fertilizantes , Purificação da Água , Membranas Artificiais , Osmose , Soluções
16.
Water Sci Technol ; 79(8): 1580-1586, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31169516

RESUMO

Over the past few decades, reverse osmosis (RO) has been the dominant technology employed in zero liquid discharge (ZLD) systems for industrial wastewater treatment (WWT). However, RO is limited to a maximum operating salinity of about 75 g kg-1. Electrodialysis (ED) is a potentially attractive option as it can achieve much higher concentrations, thereby reducing the capacity and energy demand of the subsequent evaporation step. Feed-and-bleed experiments were undertaken on a laboratory-scale ED stack using a series of model solutions based on the most common inorganic salts with the aim of determining maximum achievable concentrations. The maximum salt concentration achievable via ED ranged between 104.2 and 267.6 g kg-1, with levels predominantly limited by water transport. In addition, a straightforward review of how ED incorporation can affect ZLD process economics is presented. The operational cost of an ED-based ZLD system for processing RO retentate was almost 20% lower than comparable processes employing high-efficiency RO and disc tubular RO. As the ED-based ZLD system appears economically preferable, and as maximum achievable concentrations greatly exceeded RO operating limits, it would appear to be a promising approach for bridging the gap between RO and evaporation, and may even eliminate the evaporation step altogether.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Filtração , Membranas Artificiais , Osmose , Salinidade , Cloreto de Sódio , Águas Residuárias , Purificação da Água
17.
Plant Physiol Biochem ; 141: 306-314, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31207491

RESUMO

Prosopis strombulifera (Lam.) Benth. is a halophytic shrub found in highly saline soils in Argentina, with high tolerance against NaCl but strong growth inhibition by Na2SO4. In the present study, the differences in the physiological responses caused by these salts and an iso-osmotic combination thereof on photosynthesis, mineral composition and metabolism were analyzed. Na2SO4 treated plants were the most affected by salinity, showing a significant decrease in several photosynthetic parameters. Proline and cysteine accumulated significantly in the plants in response to salt stress. These results show by the first time that the SO42- anion is triggering damage in the photosynthetic apparatus and consequently affecting the photosynthetic process, which may explain the strong growth inhibition in these plants at high salinity. Moreover, the SO42- anion provoke challenges in the incorporation of nutrients, decreasing the levels of K, Ca, P and Mg, and inducing a strong antioxidant activity in P. strombulifera.


Assuntos
Fotossíntese , Prosopis/metabolismo , Cloreto de Sódio/química , Sulfatos/química , Ânions , Argentina , Cálcio/química , Clorofila/química , Grupo dos Citocromos b/metabolismo , Magnésio/química , Osmose/efeitos dos fármacos , Fósforo/química , Complexo de Proteína do Fotossistema II/metabolismo , Folhas de Planta/metabolismo , Proteínas de Plantas/metabolismo , Raízes de Plantas/metabolismo , Brotos de Planta/metabolismo , Potássio/química , Prosopis/efeitos dos fármacos , Ligação Proteica , Salinidade , Sódio/química
18.
Chemosphere ; 232: 87-95, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31152907

RESUMO

The removal of Co, Sr and Cs ions form simulated radioactive wastewater using forward osmosis (FO) process was investigated. The effect of various factors on nuclide transport was examined, including membrane orientation, NaCl concentration, flow velocity, and the main factors were identified by correlation analysis. The mechanisms of nuclides transfer through membrane were explored. The results indicated that the active layer facing draw solution (AL-DS) had higher nuclide flux than AL-FS. At AL-FS mode, the highest flux of Co, Sr and Cs were only 1.54, 10.22 and 15.63 mg m-2 h-1 respectively by cellulose triacetate with embedded polyester screen support (CTA-ES) membrane. At AL-DS mode, the flux of Co and Cs increased when NaCl concentration and flow velocity increased. Convection, diffusion and electrostatic interactions were found to influence the nuclide transport all together. The Pearson correlation and partial correlation analysis identified that the diffusion coefficient of nuclides and reverse NaCl flux were the most important factors affecting nuclide flux through cellulose triacetate membrane. The water flux, NaCl concentration, flow velocity and partition coefficient were not the main affecting factors for nuclide flux.


Assuntos
Eliminação de Resíduos Líquidos/métodos , Poluentes Radioativos da Água/análise , Celulose/análogos & derivados , Radioisótopos de Césio/análise , Radioisótopos de Cobalto/análise , Membranas Artificiais , Osmose , Cloreto de Sódio , Radioisótopos de Estrôncio/análise , Águas Residuárias , Água , Purificação da Água/métodos
19.
Chemosphere ; 232: 264-272, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31154187

RESUMO

Recovery of heavy metals in acid mine drainage (AMD) such as Mn, Fe, Cu, Zn, As, Cd and Pb was evaluated using volume retarded osmosis and low-pressure membrane (VRO-LPM) process. In VRO-LPM process, the draw solution (DS) is regenerated by the naturally generated pressure, giving its economic value. Ethylenediaminetetraacetic acid tetrasodium salt (EDTA-4Na) and Poly (sodium-4-styrenesulfonate, PSS-Na) were used and compared to determine more suitable DS in heavy metal recovery from the AMD. Forward osmosis (FO) and nanofiltration (NF) membrane were employed in VRO-LPM process, due to the low EDTA-4Na rejection (about 50%) in ultrafiltration (UF) process. For the FO part in the VRO-LPM process, PSS-Na had flux values of 0.12, 0.11 and 0.05 L m-2 h-1 and at osmotic pressure of 8.9, 12 and 13 bar, respectively. Unlike the flux values, the RSF of PSS remained at 0.01 mmol h-1 at all osmotic pressures. For EDTA-4Na, the flux values were 0.10, 0.06 and 0.04 L m-2 h-1, which are relatively higher than those of PSS-Na; and the RSF values were 0.1, 1.2, 2.2 mmol h-1, which are higher compared to those of PSS-Na. Unlike PSS-Na, RSF for EDTA-4Na increased as the concentration increases. In the NF part of the VRO-LPM process, PSS-Na had higher water flux and rejection than EDTA-4Na, and the flux and rejection both decreased with concentration for both PSS-Na and EDTA-4Na. The overall rejection in VRO-LPM process was over 95% for all heavy metal ions. Therefore, VRO-LPM process has proven its ability to be used in AMD treatment for heavy metal removal.


Assuntos
Metais Pesados/análise , Poluentes Químicos da Água/análise , Purificação da Água/métodos , Membranas Artificiais , Osmose , Pressão Osmótica , Pressão , Ultrafiltração , Água
20.
J Environ Manage ; 246: 239-246, 2019 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-31176985

RESUMO

A forward osmotic membrane bioreactor for sludge anaerobic digestion (ad-OMBR) could realize high-solid digestion via drawing moisture out by forward osmosis (FO). Methane production and microbial community evolution were monitored in an ad-OMBR as the total solids (TS) content was gradually increased. With magnesium chloride (MgCl2) and cellulose triacetate (CTA) membrane as a draw solution and FO membrane, respectively, the ad-OMBR exhibited better performance than the conventional digester, with higher solid content, organic degradation and methane content in biogas. The conductivity of the ad-OMBR did not increase, potentially because of the formation of struvite crystals aided by the reverse-fluxed Mg2+ ions. Microbial diversity increased along with the increase in solid content based on the Shannon index, while the most operational taxonomic units were obtained in the 8% TS sludge Although phylum Firmicutes decreased when the TS content was raised to 11%, the relative abundance of Proteobacteria, Chloroflexi, Actinobacteria, and Bacteroidetes, which could also degrade organic matter, increased with increasing TS in ad-OMBR. FO membrane fouling in ad-OMBR was highly reversible.


Assuntos
Membranas Artificiais , Esgotos , Anaerobiose , Reatores Biológicos , Metano , Osmose
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