• Membrane and Water Treatment
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• v.8 no.4
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• pp.323-336
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• 2017

The main challenge in many applications of acetic acid is acid dehydration and its recovery from wastewater streams. Therefore, the performance of polyamide thin film composite is evaluated to separate acetic acid from water. To reach this goal, the formation of polyamide layer on polysulfone support membrane was investigated via interfacial polymerization (IP) of meta-phenylenediamine (MPD) in water with trimesoyl chloride (TMC) in hexane. Also, the effect of synthesis conditions, such as concentration of monomers and curing temperature on separation of acetic acid from water were investigated by reverse osmosis process. Moreover, the separation mechanism was discussed. The solute permeation was carried out under applied pressure of 5 bar at $25^{\circ}C$. Surface properties of TFC membrane were characterized by ATR-FTIR, SEM and AFM. The performance test indicated that 3.5 wt% of MPD, 0.35 wt% of TMC and curing temperature of $75^{\circ}C$ are the optimum conditions. Moreover, the permeate flux was $4.3{\frac{L}{m^2\;h}}$ and acetic acid rejection was about 43% at these conditions.

• Membrane and Water Treatment
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• v.10 no.6
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• pp.451-460
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• 2019

Thin film composite membranes incorporated with nano-sized hydrophilic zeolite -A were successfully prepared via interfacial polymerization (IP) on porous blend PES/PAN support for water desalination. The thin film nanocomposite membranes were characterized by SEM, contact angle and performance test with 7000 ppm NaCl solution at 7bar. The results showed that the optimum zeolite loading amount was determined to be 0.1wt% with permeate flux 29LMH.NaCl rejection was improved from 69% to 92% compared to the pristine polyamide membrane where the modified PA surface was more selective than that of the pristine PA. In addition, there was no significant change in the permeate flux of the thin film nanocomposite membrane compared with that of the pristine PA in spite of the formation of the dense polyamide layer. The stability of the polyamide layer was investigated for 15 days and the optimized membrane presented the highest durability and stability.

• Membrane and Water Treatment
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• v.6 no.4
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• pp.309-321
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• 2015

We report in this study the synthesis of mixed matrix reverse osmosis membranes by interfacial polymerization (IP) of thin film nanocomposite (TFNC) on porous polysulfone supports (PS). This paper investigates the synthesis of ZnO nanoparticles (NPs) using the sol-gel processing technique and evaluates the performance of mixed matrix membranes reached by these aerogel NPs. Aqueous m-phenyl diamine (MPD) and organic trimesoyl chloride (TMC)-NPs mixture solutions were used in the IP process. The reaction of MPD and TMC at the interface of PS substrates resulted in the formation of the thin film composite (TFC). NPs of ZnO with a size of about 25 nm were used for the fabrication of the TFNC membranes. These membranes were characterized and evaluated in comparison with neat TFC ones. Their performances were evaluated based on the water permeability and salt rejection. Experimental results indicated that the NPs improved membrane performance under optimal concentration of NPs. By changing the content of the filler, better hydrophilicity was obtained; the contact angle was decreased from $74^{\circ}$ to $32^{\circ}$. Also, the permeate water flux was increased from 26 to 49 L/m2.h when the content of NPs is 0.1 (wt.%) with the maintaining of lower salt passage of 1%.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.281-289
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• 2019

Desalination plants are generally studied with higher operating costs compared to water supply facilities. This study was conducted to reduce the cost of water production and to preserve existing water resources. Therefore, the purpose of this study was to utilize the control valves to increase maximum efficiency, thereby reducing the power of the pumps and operating costs. Specific energy consumption was shown to reduce the process operating power by up to 1.7 times from 6.17 to $3.55kWh/m^3$ based on seawater reverse osmosis 60 bar. In addition, the water intake process was divided into pre, inter, and post-according to the use method of blasting, and the water treatment process was divided into pre, inter, and post blending. In order to reduce power consumption, the blending process was combined to operate the facility, which resulted in the reduction of power consumption in the order post > pre-inter> inter blending.

• Membrane and Water Treatment
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• v.15 no.1
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• pp.31-39
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• 2024

The flow in a nanopore of filtration membrane is often multiscale and consists of both the adsorbed layer flow and the intermediate continuum fluid flow. There is a controversy on which interface the slippage should occur in the nanopore filtration: On the adsorbed layer-pore wall interface or on the adsorbed layer-continuum fluid interface? What is the difference between these two slippage effects? We address these subjects in the present study by using the multiscale flow equations incorporating the slippage on different interfaces. Based on the limiting shear strength model for the slippage, it was found from the calculation results that for the hydrophobic pore wall the slippage surely occurs on the adsorbed layer-pore wall interface, however for the hydrophilic pore wall, the slippage can occur on either of the two interfaces, dependent on the competition between the interfacial shear strength on the adsorbed layer-pore wall interface and that on the adsorbed layer-continuum fluid interface. Since the slippage on the adsorbed layer-pore wall interface can be designed while that on the adsorbed layer-continuum fluid interface can not, the former slippage can result in the flux through the nanopore much higher than the latter slippage by designing a highly hydrophobic pore wall surface. The obtained results are of significant interest to the design and application of the interfacial slippage in nanoporous filtration membranes for both improving the flux and conserving the energy cost.

• Journal of the Microelectronics and Packaging Society
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• v.24 no.1
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• pp.75-81
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• 2017

The effects of KOH pretreatment and annealing conditions on the interfacial adhesion and the reliability between epoxy resin and polyimide substrate in the flexible printed circuit board were quantitatively evaluated using $180^{\circ}$ peel test. The initial peel strength of the polyimide without the KOH treatment was 29.4 g/mm and decreased to 10.5 g/mm after 100hrs at $85^{\circ}C/85%$ R.H. temperature/humidity treatment. In case of the polyimide with annealing after KOH treatment, initial peel strength was 29.6 g/mm and then maintained around 27.5 g/mm after $85^{\circ}C/85%$ R.H. temperature/humidity treatment. Systematic X-ray photoelectron spectroscopy analysis results showed that the peel strength after optimum annealing after KOH treatment was maintained high not only due to effective recovery of the polyimide damage by the polyimide surface treatment process, but also effective removal of metallic ions and impurities during various wet process.

• Journal of the Microelectronics and Packaging Society
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• v.23 no.3
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• pp.69-75
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• 2016

This study investigated the effect of heat treatment conditions not only on the Cr surface crack propagation behaviors but also on the Ni/Cr interfacial reaction characteristics in electroless Ni/electroplated Cr double coating layers on Cu substrate. Clear band layer of Ni-Cr solid solutions were developed at Ni/Cr interface after heat treatment at $750^{\circ}C$ for 6 h. Channeling cracks formed in Cr layer after 1 step heat treatment, that is, heat treatment after Ni/Cr plating, while little channeling cracks formed after 2 step heat treatment, that is, same heat treatments after Ni and Cr plating, respectively, due to residual stress relaxation due to crystallization of Ni layer before Cr plating.

• Membrane and Water Treatment
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• v.4 no.2
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• pp.109-126
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• 2013

Surface modification by low-pressure ammonia ($NH_3$) plasma on commercial thin-film composite (TFC) membranes was investigated in this study. Surface hydrophilicity, total surface free energy, ion exchange capacity (IEC) and zeta (${\zeta}$)-potentials were determined for the TFC membranes. Qualitative and quantitative analyses of the membrane surface chemistry were conducted by attenuated total reflectance Fourier transform infrared (ATR FT-IR) spectroscopy. Results showed that the $NH_3$ plasma treatment increased the surface hydrophilicity, in particular at a plasma treatment time longer than 5 min at 50 W of plasma power. Total surface free energy was influenced by the basic polar components introduced by the $NH_3$ plasma, and isoelectric point (IEP) was shifted to higher pH region after the modification. A ten (10) min $NH_3$ plasma treatment at 90 W was found to be adequate for the TFC membrane modification, resulting in a membrane with better characteristics than the TFC membranes without the modification for water treatment. The thin-film chemistry (i.e., fully-aromatic and semi-aromatic nature in the interfacial polymerization) influenced the initial stage of plasma modification.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.1
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• pp.47-52
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• 2008

As the packing density of IC devices gets ever higher, the thickness of the gate $SiO_2$ layer of the MOS devices is now required to be reduced down to 1 nm. For such a thin $SiO_2$ layer, the MOS device cannot operate properly because of tunneling current and threshold voltage shift. Hence there has been much effort to develop new dielectric materials which have higher dielectric constants than $SiO_2$ and is free from such undesirable effects. In this work, the physical and electrical characteristics of ALD $ZrO_2$ film have been studied. After deposition of a thin ALD $ZrO_2$ film, it went through thermal treatment in the presence of argon gas at $800^{\circ}C$ for 1 hr. The characteristics of morphology, crystallization kinetics, and interfacial layer of $Pt/ZrO_2/Si$ samples have been investigated by using the analyzing instruments like XRD, TEM and C-V plots. It has been found that the characteristics of the $Pt/ZrO_2/Si$ device was enhanced by the thermal treatment.

• Composites Research
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• v.12 no.2
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• pp.91-100
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• 1999

The manufacture of high strength polyethylene(HSPE) tape yarns has been accomplished by a solid state processing(SSP) method as the compaction of ultra-high molecular weight polyethylene(UHMWPE) powders and drawing of the compacted film under the melting point without any organic solvents. In this study, the characteristics of HSPE tape yarns produced by SSP which is desirable for production cost and environmental aspect were analyzed. As the results, tensile strengths of HSPE tape yarns increased with increasing the draw ratio and the fracture morphology of highly drawn HSPE tape yarns showed more fibrillar shape than the low drawn one. Interfacial shear strengths of HSPE tape yarns with vinylester resin increased by $O_2$ plasma treatment and maximum interfacial shear strength was obtained in the plasma treatment condition of 100W and 5min. In addition, mechanical properties of HSPE tape yarn reinforced composites were investigated and compared with those of the gel spun HSPE fiber reinforced composites.