A membrane technology is one of the basic categories of water purification technologies that are used to treat wide range of salinity water from brackish to sea water. Bipolar membrane (BPM) is a special type of catalytic ion exchange membrane (IEM) which involves water dissociation reaction in intermediate layer. Here monopolar and bipolar IEMs with Ru (water dissociation catalyst) as intermediate layer (IL) are prepared with resin and glass fiber reinforcements using functionalized polysulfone polymer (RBPM-Ru). The prepared RBPM-Ru was characterized using universal testing machine, thermo gravimetric analysis, contact angle and chemical stability through conductivity and water absorption studies. In addition the present study highlights the new method of characterizing RBPM-Ru especially through image segmentation technique as one of the prior characteristic technique before SEM analysis to confirm its bi-layer formation in a single membrane because of its advantages like no cost requirement and less time consumption method with the same quality of accuracy. The performance of RBPM-Ru in a two-compartment electrodialytic cell was evaluated using correlated parameters such as pH, concentration and conductivity studies in both compartments. By using current voltage graph (I-V) the importance of incorporating catalytic material in IL for enhancing BPM water dissociation reaction were identified. Finaly it can be concluded that RBPM-Ru was expected to have better process efficiency due to lower co-ion leakage capacity when compared with results of polystyrene–divinylbenzene (PSDVB) based BPM under similar experimental conditions.

Controlling non-point source pollutants (NPSPs) is critical in achieving good surface water quality; the contribution of road runoff has recently received increased attention. This study monitored the runoff characteristics of NPSPs, including suspended solids, particle size distribution, heavy metals, organic matter, and nutrients, from asphalt and concrete roads. Water quality parameters, including biochemical oxygen demand (BOD), chemical oxygen demand (COD), and nutrients of the receiving reservoir, were also investigated. During the first flush, the changes in pollutant concentrations over time were higher on concrete roads than asphalt roads. Concentrations peaked over a short period, while an increased pollutant concentration may be present several days after rain. The runoff concentration and particle size distribution were higher on concrete roads, whereas the concentrations of heavy metals were similar in asphalt and concrete roads. The organic matter concentration of asphalt roads was higher, or identical, to that in the first flush from concrete roads; this may be associated with the road location. Water quality analysis of the reservoir showed relatively good results for BOD, COD, and nutrient concentrations. Road construction was a factor that determined the characteristics of NPSPs in road runoff.

Monosodium glutamate (MSG) was evaluated as a draw solute (DS) of forward osmosis–nanofiltration (FO-NF) process for sewage thickening. Water flux (Jw) and reverse draw solute flux (Js) through FO membrane with MSG were compared to those with NaCl as the reference DS. In addition, the influence of MSG to anaerobic digestion of concentrated sewage for methane gas production was investigated. The Js/Jw for MSG was 0.0015mol/L at 1M of initial concentration with a CTA(HTI) membrane, which was 6 % of that for NaCl, while the water flux (Jw) for MSG (ca. 10 L/m2h) was comparable to that for NaCl in FO processes. MSG recovered up to 98% by NF process, which changed with applied membrane and MSG concentration. The collected primary effluent from the full-scale wastewater treatment plant was thickened up to nine times in terms of volumetric concentration factor. The physical membrane flushing by a water could effectively recover the flux. The inhibitory effects of MSG on anaerobic methane production could be negligible and the gas production potential increased.

The electrochemical reduction of nitrate using a divided electrolytic cell in combination with Zn cathode and (Pt)/Ti anode reduced the high concentrations of nitrate (1,000 mg NO3-N/L). A proton exchange membrane (Nafion-117) was used to increase the nitrate reduction efficiency by preventing the re-oxidation of nitrite produced during the reduction process. The current density and anolyte concentration, considered as parameters, were tested to assess the electrochemical reduction of nitrate. The reduction of nitrate shortened the electrolysis time in proportion to the current density, and the time for 90% removal was 5 h at 5 mA/cm2, 3 h at 10 mA/cm2, and 1.8 h at 20 mA/cm2. The yields of ammonia were approximately 50%-55% of the initial nitrate-nitrogen concentration regardless of the current density and was insignificantly related to the anolyte concentration.

The microporous PTFE membrane was used for membrane distillation (MD) experiment and presented ultra-high efficiency of desalination. A hybrid desalination system combining membrane distillation and mechanical vapor compression (MD+MVR) had been developed on the basis of the MD experiment. The system featured that the latent heat and part of sensible heat of vapor from the MVR were recovered to heat the MD process, and the heating process occurred in the same module as the MD process. Models were built according to the energy and mass conservation for the system description. Based on the simulation and experimental data, when the system was assigned a treatment capacity 1000 kg h-1 for 1% saline water and with corresponding 875 kg h-1 fresh water production, it would be stuffed with 75.24 m2 of PTFE membrane and expense only 3.31 kW of electrical power, under 353 K of feed temperature in membrane module and 26 kPa of compressor suction pressure. The compressor power requirement would trade off the heat transfer area with variation of the heat transfer temperature difference. The higher the salinity concentration in the residual concentrate after distillation was, the higher the compressor power, membrane area and heat exchanger area would be.

The present study deals with a numerical investigation of heat and mass transfer in a Sweeping Gas Membrane Distillation (SGMD) used for desalination. The governing equations expressing the conservation of mass, momentum, energy and species with coupled boundary conditions were solved numerically. The slip boundary condition applied on the feed saline solution-hydrophobic membrane interface is taken into consideration showing its effects on profiles and process parameters.The numerical model was validated with available experimental data and was found to be in good agreement particularly when the slip condition is considered. The results of the simulations highlighted the effect of slip boundary condition on the velocity and temperature distributions as well as the process effectiveness. They showed in particular that as the slip length increases, the permeate flux of fresh water and process thermal efficiency rise.

This study optimized the chemical cleaning process of discarded RO membranes for reuse in less demanding separation processes. The effect of physicochemical parameters, including the temperature, cleaning time, pH of the cleaning solution, and addition of additives, on the cleaning process was investigated. The membrane performance was evaluated by testing the flux recovery rate and salt rejection before and after the cleaning process. High temperatures (45-50oC) resulted in a better flux recovery rate of 71% with more than 80% salt rejection. Equal time for acid and base cleaning 3-3 h presented a 72.43% flux recovery rate with salt rejection above 85%. During acid and base cleaning, the best results were achieved at pH values of 3.0 and 12.0, respectively. Moreover, 0.05% concentration of ethylenediaminetetraacetic acid presented 72.3% flux recovery, while 69.2% flux was achieved using sodium dodecyl sulfate with a concentration of 0.5%; both showed >80% salt rejection, indicating no damage to the active layer of the membrane. Conversely, 0.5% concentration of sodium percarbonate showed 83.1% flux recovery and 0.005% concentration of sodium hypochlorite presented 85.2% flux recovery, while a high concentration of these chemicals resulted in oxidation of the membrane that caused a reduction in salt rejection.

This paper presents the multiscale calculation results of the very fast volume transport in micro/nano cylindrical tubes with the wall slippage. There simultaneously occurs the adsorbed layer flow and the intermediate continuum fluid flow which are respectively on different scales. The modeled fluid is water and the tube wall is somewhat hydrophobic. The calculation shows that the power loss on the tube no more than 1.0 Watt/m can generate the wall slippage even if the fluid-tube wall interfacial shear strength is 1 MPa; The power loss on the scale 104 Watt/m produces the volume flow rate through the tube more than one hundred times higher than the classical hydrodynamic theory calculation even if the fluid-tube wall interfacial shear strength is 1 MPa. When the wall slippage occurs, the volume flow rate through the tube is in direct proportion to the power loss on the tube but in inverse proportion to the fluid-tube wall interfacial shear strength. For low interfacial shear strengths such as no more than 1 kPa, the transport in the tube appears very fast with the magnitude more than 4 orders higher than the classical calculation if the power loss on the tube is on the scale 104 Watt/m.

A POM-membrane was fabricated by immobilizing a keggin type polyoxometalate (POM) H5PV2Mo10O40 onto the surface of microporous flat-sheet polymeric polyvinylidene fluoride (PVFD) membrane using a chemical deposition method. The POM-membrane was characterized by FT-IR, SEM and EDX to confirm existing of the POM onto the membrane surface. The POM-membrane was used to remove an anionic textile dye (Reactive Black 5 named as an RB5) from aqueous phases with a cross-flow membrane filtration and a batch adsorption system. The dye removal efficiency of the POM-membrane using the cross-flow membrane filtration system and the batch adsorption system was about 88% and 98%, respectively. The influence factors such as contact time, adsorbent dosage, pH, and initial dye concentration were investigated to understand the adsorption mechanism of the RB5 dye onto the POM-membrane. To find the best fitting isotherm model, Langmuir, Freundlich, BET and Harkins-Jura isotherm models were used to analyze the experimental data. The isotherm analysis showed that the Langmuir isotherm model was found to the best fit for the adsorption data (R 2=0.9982, qmax=24.87 mg/g). Also, adsorption kinetic models showed the pseudo second order kinetic model was found the best model to fit the experimental data (R2=0.9989, q=8.29 mg/g, C0=15 ppm). Moreover, after four times regeneration with HNO3 acid, the POM-membrane showed high regenerability without losing dye adsorption capacity.

In recent years, the generation of disinfectant by-products (DBPs) in drinking water system has been highlighted for their potential negative impact on humans. A commonly used disinfectant, chlorine, produces a by-product which is highly hazardous and a known carcinogen. This study investigated the toxic effects of DBPs from several organic matter as a function of contact time with chlorine-based disinfectants were investigated using zebrafish. The results indicated that the generation of DBPs was dependent on the composition of dissolved organic matter (DOM) in water. Suwannee river natural organic matter and experimental site water sample (complex DOM) were almost 2.5 times higher than that of a single dissolved organic matter, such as microcystin-LR (MCLR) at 120 min. The behavior of zebrafish was significantly affected by complex composition DOM. In vivo biomarker analysis result from lipid profile analysis, reaction in vivo showed different depending on the composition of the DOM. Through this study, the effect of DBPs were observed via lipid metabolic and movement changes in aquatic organisms can be considered as a new biomarker for the drinking water risk assessment.