Separation of 1,3-Propanediol by Nanofiltration Method

The application potential of nanofiltration (NF) method on the separation of 1,3-propanediol (1,3-PDO) from synthetically prepared fermentation broth was investigated. The rejection tests at different pressures (10, 20, 30 bar) and pH values (7 and 10) were performed on laboratory scale using Desal DL-5 NF membrane. The rejection of succinic acid, having the molecular weight larger than or closer to the molecular weight cut-offs (MWCOs) of Desal-5 DL NF membrane was 100% independent of operating pressure and pH. The results of this study clearly showed that NF process is a very promising pretreatment step for the removal of volatile organic acids from the fermentation broth

Electrochemical Treatment of Textile Dye Bath Wastewater Using Activated Carbon Cloth Electrodes

The performance of electrooxidation (EO) treatment using activated carbon cloth (ACC) electrodes on textile dye bath wastewater was investigated. ACC electrode pairs were used as anode/cathode for EO experiments. The effect of current density (50–150 A/m2 ), operating time (0–90 minutes), and solution pH (6-11) were tested for removal of chemical oxygen demand (COD), color, and chloride, as well as the changes in conductivity. 95.5% COD and color removal efficiencies were obtained at current density (CD) of 100 A/m2 at solution pH of 10 for 90 minutes. Moreover, the chloride concentration decreased from 4254 to 35.5 mg/L and solution conductivity decreased from 160 to 131 mS/cm at the same conditions. Operating cost of the EO process was calculated to be 3.13 US$/m3 for 36 kWh/m3 energy consumption. The results indicated that the EO process with ACC electrodes achieved high pollutant removal from textile dye bath wastewater

Nanofiltration of single and mixture solutions containing anionics and nonionic surfactants below their critical micelle concentrations (CMCs)

Nanofiltration (NF) of linear alkyl benzene sulfonate (LABS), sodium dodecylether sulfate (SLES) as anionic surfactants and of nonylphenol ethoxylate (NPE) as nonionic surfactant for selected concentrations below CMC (critical micelle concentration) was carried out using various membranes as NF PES10, N 30F and XN 45. Membrane fouling was observed in the order of XN 45 > NF PES10 > N 30F for LABS, SLES and mixture solutions, while the order was as NF PES 10 > N 30F > XN 45 for NPE solution. The most fouled membrane, XN 45, exhibited the least fouling on the surface in opposition to N 30F. In single solutions, the highest rejection of LABS and SLES was obtained around 97-98% by NF PES 10 and N 30F, whereas when XN 45 was used, the rejection rate was around 93%. In mixture solution, the rejection rates were observed to be around 97 and 98% by NF PES 10 and N 30F, respectively, which were quite different from XN 45 rejection rates. The enhancement of rejections compared to the adsorption of single surfactants, except for NPE-XN 45 couple, could have been taken place by synergism between nonionic and anionics as a function of both stronger interactions between surfactants and surface and, more effective physical separation forces based on micellation. In NPE-XN 45 couple, NPE was rejected predominantly under the effect of binding LABS, which had the highest feed concentration in mixture, on the membrane surface. Consequently, it was determined that, XN 45 for nonionic (NPE) and NF PES10 for anionics (LABS and SLES) and mixture solution (LABS + SLES + NPE) performed the best performance in NF of single and mixture surfactant solutions. (c) 2006 Elsevier B.V. All rights reserved

Soluble Microbial Products Removal Profile and Morphological Assessment of Submerged Ultrafiltration Membrane

Performance of ultrafiltration membranes were investigated with submerged membrane in terms of removal of soluble microbial products (SMP) (as proteins and carbohydrates) and fouling mechanisms. Cellulose (UC) and polyethersulphone (UP) membranes with different molecular weight cut off (MWCO) (5, 10, 30 kDa for UC and 5, 10, 20 kDa for UP) were tested in the bioreactor. The quality of permeate was compared in terms of SMP and COD. There was no significant difference in the total SMP removal effectives for both the UC and UP membranes with different MWCO characteristics. However, UP membranes were relatively more effective in removing soluble carbohydrates, while UC membranes were more effective in removing soluble proteins. The submerged membrane bioreactor achieved organic removal efficiencies ranging from 98.1±0.2% to 99.2±0.3% based on the soluble COD levels. Analysis of the membrane performance data by resistances-in-series model indicated that cake fouling was the dominant membrane fouling mechanisms. Increasing the MWCO was resulted in higher membrane flux but lower SMP removal. Morphological examination of the membranes by SEM and AFM showed significant accumulation of organisms on the membrane surface