• Journal of Korean Society of Environmental Engineers
• /
• v.36 no.2
• /
• pp.147-152
• /
• 2014

In this research, polysulfone hollow fiber membrane was used to recover $CO_2$ which is one of greenhouse gases from flue gas stream being emitted after the combustion of fossil fuels. The prerequisite requirement is to design the membrane process producing high-purity $CO_2$ from flue gas. For separation of $CO_2$, a membrane module and flue gas containing 10% carbon dioxide was used. The effects of operating conditions such as pressure, temperature, feed gas composition and multi-stage membrane on separation performance were examined at various stage cuts. Higher operating pressure and temperature increased carbon dioxide concentration and recovery ratio in permeate. Recovery ratio and separation efficiency increased if a higher content of $CO_2$ injection gas composition. Three-stage membrane system was producing a 95% $CO_2$ with 90% recovery from flue gas. The separation efficiency of three-stage membrane system was higher than one-stage system.

• Membrane Journal
• /
• v.21 no.4
• /
• pp.351-359
• /
• 2011

For advanced drinking water treatment of high turbidity water, we used the hybrid process that was composed of photocatalyst packing in space of between outside of multi-channel ceramic microfiltration membrane and membrane module inside. Photocatalyst was polypropylene (PP) beads coated $TiO_2$ powder by CVD (chemical vapor deposition) process. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, standard NOM solution was prepared with humic acid and kaolin. Water-back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling. Resistance of membrane fouling ($R_f$) increased and J decreased as concentration of humic acid changed from 2 mg/L to 10 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L. Then, treatment efficiency of turbidity and $UV_{254}$ absorbance were above 96.4% and 78.9%, respectively. As results of treatment portions by membrane filtration, photocatalyst adsorption, and photo-oxidation in (MF), (MF + $TiO_2$), (MF + $TiO_2$ + UV) processes, turbidity was treated little by photocatalyst adsorption, and photo-oxidation. However, treatment portions of $UV_{254}$ absorbance by adsorption (MF + $TiO_2$) and photo-oxidation (MF + $TiO_2$ + UV) at humic acid of 4 mg/L and 6 mg/L were above 9.0, 9.5 and 8.1, 10.9%, respectively.

• Membrane and Water Treatment
• /
• v.12 no.1
• /
• pp.43-49
• /
• 2021

The Commercial polymeric membranes like Polysulfone (PSF), Polyvinylidene difluoride (PVDF) and Polyacrylonitrile (PAN) which are an integral part of water purification investigation were chosen for the shockwave (SW) exposure experiment. These membranes were prepared by blending polymer (wt. %) / DMF (solvent) followed by phase-inversion casting technique. Shockwaves are generated by using Reddy Tube lab module (Table-top Shocktube) with range of pressure (1.5, 2.5 and 5 bar). Understanding the changes in membrane before and after shock wave treatment by parameters, i.e., pure water flux (PWF), rejection (%), porosity, surface roughness (AFM), morphology (SEM) and contact angle which can significantly affect the membrane's performance. Flux values PSf membranes shows increase, 465 (pristine) to 524 (1.5wt%) LMH at 50 Psi pressure and similar enhancement was observed at 100Psi (625 to 696 LMH). Porosity also shows improvement from 73.6% to 76.84% for 15wt% PSf membranes. It was observed that membranes made of polymers such as PAN and PSF (of high w/w %) exhibits some resistance against shockwaves impact and are stable compared to other membranes. Shockwave pressure of up to 1.5 bar was sufficient enough to change properties which are crucial for performance. Membranes exposed to a maximum pressure of 5 bar completely scratched the surface and with minimum pressure of 1.5bar is optimum enough to improve the water flux and other parameters. Initial results proved that SW may be suitable alternative route to minimize/control membrane fouling and improve efficiency.

• Membrane Journal
• /
• v.19 no.1
• /
• pp.7-18
• /
• 2009

In this study, we used the hybrid module that was composed of granular activated carbons (GAC) packing between module inside and outside of tubular ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, modified solution was prepared with humic acid and kaolin. We were investigated effect of water-back-flushing time (BT) and water-back-flushing period (FT) to minimize membrane fouling and to enhance permeate flux (J) in the hybrid process, and tried to find the optimal operating conditions. As a result, resistance of membrane fouling ($R_f$) was slightly decreased according to increasing BT. Also, the shorter FT was the more effective to reduce $R_f$ and to enhance J because of frequent water-back-flushing. However, the optimal BT and FT conditions were 10 sec and 8 min respectively when operating costs were considered. Then, the optimal conditions derived from our experiments of modified solution were applied to lake water treatment. As a result, average treatment efficiencies of turbidity, $UV_{254}$ absorbance, and $COD_{Mn}$ were very high as 99.11%, 91.40% and 89.34%, respectively, but that of TDS was low as 30.05%.

• Membrane Journal
• /
• v.18 no.3
• /
• pp.191-197
• /
• 2008

In this study, we used hybrid module that was composed of packing granular activated carbon (GAC) between module inside and outside of ceramic microfiltration membrane for advanced drinking water treatment. Instead of natural organic matters (NOM) and fine inorganic particles in natural water source, synthetic water was prepared with humic acid and kaolin. Packing fraction of GAC was changed from 0 to 24.05% to see effect of packing fraction. As a result, changing curves of resistance of membrane fouling ($R_f$) and permeate flux (J) during 3 h operation were almost overlapped independent of packing fraction of GAC. Treatment efficiencies of turbidity were very high above 99.46% at all packing fractions of GAC. And treatment efficiency of NOM, which was measured by $UV_{254}$ absorbance, was the highest value of 99.43% at packing fraction of 24.05%. Then, we operated the hybrid process during 13 h at packing fraction of 24.05%. As a result, J was rapidly dropped according to increase of membrane fouling within initial 1 h of operation, and almost constant after 3 h. And treatment efficiencies of turbidity and NOM were stable and high values of 99.52% and 96.63%, respectively.

• Membrane Journal
• /
• v.19 no.4
• /
• pp.277-284
• /
• 2009

In order to select the most suitable membrane to the concentration of vanadium and silica in groundwater, two different commercial NF membrane modules (NE2540-90 and NF90-2540) and three different commercial RO membrane modules (BW30-2540, RE2540-TE, and XLE-2540) were tested. The membrane characteristics test results showed that NE2540-90 module was the most efficient because of higher permeate flux and similar rejection coefficient. Using NE2540-90 module at the transmembrane pressure of $8\;kgf/cm^2$, it was found that the rejection coefficients of vanadium, silica, aluminium, chromium, iron, boron, strontium, and barium were 98.2%, 99.0%, 92.0%, 83.6%, 96.0%, 45.1%, 98.6%, and 69.5%, respectively. It was possible that vanadium and silica contents of groundwater were concentrated into $148.9\;{\mu}g/L$ and 85.8 mg/L respectively by six-stages NF process at the recovery ratio of 15%. The waters produced by NF, which are enriched in vanadium and silica content, are expected to be commercialized the various functional mineral waters.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.25 no.1
• /
• pp.5-13
• /
• 2017

Polypropylene is the main existing material in the domestic market being used for the filter plate because of its moldability, low cost, and commercial availability. Polypropylene filter plate once distorted due to the high-pressure during operation may cause the problem in the continuous operation of the solid-liquid separation module. Thermoplastic Poly Urethane (TPU) can be a high-performance alternative material for the filter plate in the solid-liquid separation module of the dehydration process. Hence, to predict and evaluate the TPU for structural stability in the filter plate through analytical techniques designed and experimental verification is essential. As a result, TPU filter plate had maximum strain of 27.85 MPa at 20 bar pressure condition. This result is less than TPU stress-strain limit, which ensures the structural stability of the TPU material.

• Journal of Korean Society of Water and Wastewater
• /
• v.32 no.4
• /
• pp.357-361
• /
• 2018

Forward osmosis (FO) process has been attracting attention for its potential applications such as industrial wastewater treatment, wastewater reclamation and seawater desalination. Particularly, in terms of fouling reversibility and operating energy consumption, the FO process is assumed to be preferable to the reverse osmosis (RO) process. Despite these advantages, there is a difficulty in the empirical step due to the lack of separation and recovery techniques of the draw solution. Therefore, rather than using FO alone, recent developments of the FO process have adapted a hybrid system without draw solution separation/recovery systems, such as the FO-RO osmotic dilution system. In this study, we investigated the performance of the hollow fiber FO module according to various operating conditions. The change of permeate flow rate according to the flow rates of the draw and feed solutions in the process operation is a factor that increases the permeate flow rate, one of the performance factors in the positive osmosis process. Our results reveal that flow rates of draw and feed solutions affect the membrane performance, such as the water flux and the reverse solute flux. Moreover, use of hydraulic pressure on the feed side was shown to yield slightly higher flux than the case without applied pressure. Thus, optimizing the operating conditions is important in the hollow fiber FO system.

• Membrane Journal
• /
• v.6 no.4
• /
• pp.219-226
• /
• 1996

Rotary disc ultrafiltration module(RDM) was developed for the separation of oil emulsions. This module was devised to reduce the gel polarization phenomenon by alecoupling the operation pressure and the surface velocity of solution in ultrafiltration(UF) processes. Two-shaft engaged disc type RDM having 20 rotary disc membcanes(UOP, USA) was operated under 85kPa vacuum at $25^{\circ}$C. The pressure drop due to slip flow in the two-shaft RDM was found to be proportional to $(2.5{\omega}r)^{2}$. The pure water flux of two-shaft RDM decreased by 9.95% at the angular velocity of 41.89rad/s compared to the decrease of 3.01% for one-shaft RDM at the same velocity. When the angular velocity was changed from 31.42rad/s to 2.62rad/s, the flux decline for 1% cutting oil in two-shaft RDM was 30.16% that is similar to that of one-shaft RDM. Disc gap of 3mm and 7mm did not show any significant differences in the flux for 1% cutting oil solution. A modified model for two-shaft RDM showed good agreement with the experimental results for the cutting oil solution.

• Membrane Journal
• /
• v.11 no.1
• /
• pp.14-21
• /
• 2001

Rapid backpulsing to reduce membrane fouling of hollow fiber ultrafiltration module (polyacrylonitrile with 50000 l'vlWCO, 1.4 rom OD and 0,9 mm ID) was studied with latex solutions. Values estimated by a theoretical model were compared with the ones obtained from the systems with or without backpulsing, Specific Cake resistance, time consUmt for cake growth, diffusion coefficient, and the rate constants of fnur fouling models; the complete, intermediate. standard blocking and cake filtration were calculated to obtain the theoretical values. High frequency backpulsing gave net increase of fluxes by 40~120%. Fluxes predicted by the model were in good agreement with experimental ones within 14% error bound, The optimum backpulsing strength was acquired at 20% in the ranges of 20~40% strength and the optimum frequcncv was acquired at 2 Hz in the ranges of 0.67~3 Hz.