Abstract: Desalination using solar energy coupled with membrane techniques such as vacuum membrane distillation (VMD) is considered as an interesting alternative for the production of pure water. During this work, a developed model of a polytetrafluoroethylene (PTFE) hollow fiber membrane module of a VMD unit of seawater was carried out. This simulation leads to establishing a comparison between the effects of two different equations of the vaporization latent heat on the membrane surface temperature and on the unit productivity. Besides, in order to study the effect of putting membrane modules in series on the outlet fluid temperature and on the productivity of the process, a simulation was executed.
Abstract: Fish can breathe freely under water using dissolved oxygen and survive for a long time without going out of the water. A human can also survive under water using dissolved oxygens, if properly used. He needs more dissolved oxygens than the fish, so efficient separation device is required. Since the amount of oxygen contained in water is weak, a person needs a lot of surface area to breathe in water, which leads to a large-sized device. It can be applied to various fields if it is developed as a device which is advantageous to carry in small size. In this paper, we have carried out a study on the effective use of exhalations and proposed the separation characteristics of the gas containing dissolved oxygen in the state of mixed gas considering the components of exhalation. The system was configured to have a fine bubble when the gas mixture injected into the front end of the separator. While the fluid containing the fine bubbles was supplied to the separator, the dissolved gas contained in water was separated using a vacuum pump. The gas separation amount of the separating apparatus with respect to the supplied mixed gas was measured. The amounts of separation of dissolved gas were increased as the amounts of mixed gas supplied were increased.
Abstract: Water contains dissolved oxygen that a fish needs to breathe. It is important to increase the amounts of separation of dissolved oxygen from water for diverse applications using the separation system. In this paper, a separation system of dissolved gases from water concurrently variable mixed with the exhalations using a compressor is proposed. This system takes use of exhalations to increase the amounts of separation of dissolved oxygen from water. A compressor with variable off-time and on-time is used to control the exhalations mixed with inlet water. Exhalations contain some portion of carbon dioxide, oxygen, and nitrogen. Separation of dissolved gases containing dissolved oxygen is enhanced by using exhalations. The amounts of separation and the compositions of carbon dioxide and oxygen are measured. Higher amounts of separation can make the size of the separation device smaller, and then, application areas are diversified.
Abstract: Amoxicillin is an antibiotic which is widely used to
treat various infections in both human beings and animals. However,
when amoxicillin is released into the environment, it is a major
problem. Amoxicillin causes bacterial resistance to these drugs and
failure of treatment with antibiotics. Liquid membrane is of great
interest as a promising method for the separation and recovery of the
target ions from aqueous solutions due to the use of carriers for the
transport mechanism, resulting in highly selectivity and rapid
transportation of the desired metal ions. The simultaneous processes
of extraction and stripping in a single unit operation of liquid
membrane system are very interesting. Therefore, it is practical to
apply liquid membrane, particularly the HFSLM for industrial
applications as HFSLM is proved to be a separation process with
lower capital and operating costs, low energy and extractant with
long life time, high selectivity and high fluxes compared with solid
membranes. It is a simple design amenable to scaling up for industrial
applications. The extraction and recovery for (Amoxicillin) through
the hollow fiber supported liquid membrane (HFSLM) using
aliquat336 as a carrier were explored with the experimental data. The
important variables affecting on transport of amoxicillin viz.
extractant concentration and operating time were investigated. The
highest AMOX- extraction percentages of 85.35 and Amoxicillin
stripping of 80.04 were achieved with the best condition at 6 mmol/L
[aliquat336] and operating time 100 min. The extraction reaction
order (n) and the extraction reaction rate constant (kf) were found to
be 1.00 and 0.0344 min-1, respectively.
Abstract: The separation of Hg (II) from produced water by
hollow fiber contactors (HFC) was investigation. This system
included of two hollow fiber modules in the series connecting. The
first module used for the extraction reaction and the second module
for stripping reaction. Aliquat336 extractant was fed from the organic
reservoirs into the shell side of the first hollow fiber module and
continuous to the shell side of the second module. The organic liquid
was continuously feed recirculate and back to the reservoirs. The feed
solution was pumped into the lumen (tube side) of the first hollow
fiber module. Simultaneously, the stripping solution was pumped in
the same way in tube side of the second module. The feed and
stripping solution was fed which had a countercurrent flow. Samples
were kept in the outlet of feed and stripping solution at 1 hour and
characterized concentration of Hg (II) by Inductively Couple Plasma
Atomic Emission Spectroscopy (ICP-AES). Feed solution was
produced water from natural gulf of Thailand. The extractant was
Aliquat336 dissolved in kerosene diluent. Stripping solution used was
nitric acid (HNO3) and thiourea (NH2CSNH2). The effect of carrier
concentration and type of stripping solution were investigated.
Results showed that the best condition were 10 % (v/v) Aliquat336
and 1.0 M NH2CSNH2. At the optimum condition, the extraction and
stripping of Hg (II) were 98% and 44.2%, respectively.
Abstract: In this study, a liquid phase microextraction by hollow fiber (HF-LPME) combined with high performance liquid chromatography-UV detector was applied to preconcentrate and determine trace levels of Cyproheptadine in human urine and plasma samples. Cyproheptadine was extracted from 10 mL alkaline aqueous solution (pH: 9.81) into an organic solvent (n-octnol) which was immobilized in the wall pores of a hollow fiber. Then was back-extracted into an acidified aqueous solution (pH: 2.59) located inside the lumen of the hollow fiber. This method is simple, efficient and cost-effective. It is based on pH gradient and differences between two aqueous phases. In order to optimize the HF-LPME some affecting parameters including the pH of donor and acceptor phases, the type of organic solvent, ionic strength, stirring rate, extraction time and temperature were studied and optimized. Under optimal conditions enrichment factor, limit of detection (LOD) and relative standard deviation (RSD(%), n=3) were up to 112, 15 μg.L−1 and 2.7, respectively.
Abstract: A polypropylene hollow fiber membrane module is used for separating dissolved gases which contain dissolved oxygen from water. These dissolved gases can be used for underwater breathing. To be used for a human, the minimum amount of oxygen is essential. To increase separation of dissolved gases, much water and high surface area of hollow fibers are requested. For efficient separation system, performance of single membrane module with high surface area needs to be investigated.
In this study, we set up experimental devices for analyzing separation characteristics of dissolved gases including oxygen from water using a polypropylene hollow fiber membrane module. Separation of dissolved gases from water is investigated with variations of water flow rates. Composition of dissolved gases is also measured using GC. These results expect to be used in developing the portable separation system.
Abstract: 40L of hollow fiber membrane bioreactor with solids retention times (SRT) of 30, 15 and 4 days were setup for treating synthetic wastewater at hydraulic retention times (HRT) of 12, 8 and 4 hours. The objectives of the study were to investigate the effects of SRT and HRT on membrane fouling. A comparative analysis was carried out for physiochemical quality parameters (turbidity, suspended solids, COD, NH3-N and PO43-). Scanning electron microscopy (SEM), energy diffusive X-ray (EDX) analyzer and particle size distribution (PSD) were used to characterize the membrane fouling properties. The influence of SRT on the quality of effluent, activated sludge quality, and membrane fouling were also correlated. Lower membrane fouling and slower rise in trans-membrane pressure (TMP) were noticed at the longest SRT and HRT of 30d and 12h, respectively. Increasing SRT results in noticeable reduction of dissolved organic matters. The best removal efficiencies of COD, TSS, NH3-N and PO43- were 93%, 98%, 80% and 30% respectively. The high HRT with shorter SRT induced faster fouling rate. The main fouling resistance was cake layer. The most severe membrane fouling was observed at SRT and HRT of 4 and 12, respectively with thickness cake layer of 17mm as reflected by higher TMP, lower effluent removal and thick sludge cake layer.
Abstract: The separation of silver ions from medicinal wastewater via hollow fiber supported liquid membrane (HFSLM) was examined to promote the performance of this technique. The wastewater consisting of 30mg/L silver ions and 120mg/L ferric ions was used as the feed solution. LIX84I dissolving in kerosene and sodium thiosulfate pentahydrate solution were used as the liquid membrane and stripping solution, respectively. In order to access the highest performance of HFSLM, the optimum condition was investigated via several influential variables. Final concentration of silver ions in feed solution was obtained 0.2mg/L which was lower than the discharge limit of Thailand’s mandatory.
Abstract: The mathematical equation for Separation of the
binary aqueous solution is developed by using the Spiegler- Kedem
theory. The characteristics of a B-9 hollow fibre module of Du Pont
are determined by using these equations and their results are
compared with the experimental results of Ohya et al. The agreement
between these results is found to be excellent.
Abstract: The separation of dissolved gas including dissolved oxygen can be used in breathing for a human under water. When one is suddenly wrecked or meets a tsunami, one is instantly drowned and cannot breathe under water. To avoid this crisis, when we meet waves, the dissolved gas separated from water by wave is used, while air can be used to breathe when we are about to escape from water. In this thesis, we investigated the separation characteristics of dissolved gas using the pipe type of hollow fiber membrane with polypropylene and the nude type of one with polysulfone. The hollow fiber membranes with good characteristics under water are used to separate the dissolved gas. The hollow fiber membranes with good characteristics in an air are used to transfer air. The combination of membranes with good separation characteristics under water and good transferring one in an air is used to breathe instantly under water to be alive at crisis. These results showed that polypropylene represented better performance than polysulfone under both of air and water conditions.
Abstract: Cs-type nanocomposite zeolite membrane was successfully synthesized on an alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm; cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.
Abstract: A double module hollow fiber supported liquid
membrane (HFSLM) was applied to selectively separate lead and
mercury ions from dilute synthetic produced water. The experiments
were investigated on several variables: types of extractants
(D2EHPA, Cyanex 471, Aliquat 336, and TOA), concentration of the
selected extractant and operating time. The results clearly showed
that the double module HFSLM could selectively separate Pb(II) and
Hg(II) in feed solution at a very low concentration to less than the
regulatory discharge limit of 0.2 and 0.005 mg/L issued by the
Ministry of Industry and the Ministry of Natural Resource
Environment, Thailand. The highest extractions of lead and mercury
ions from synthetic produced water were 96% and 100% using 0.03
M D2EHPA and 0.06 M Aliquat 336 as the extractant for the first
and second modules.
Abstract: For stricter drinking water regulations in the future, reducing the humic acid and disinfection byproducts in raw water, namely, trihalomethanes (THMs) and haloacetic acids (HAAs) is worthy for research. To investigate the removal of waterborne organic material using a lab-scale of bio-activated carbon filter under different EBCT, the concentrations of humic acid prepared were 0.01, 0.03, 0.06, 0.12, 0.17, 0.23, and 0.29 mg/L. Then we conducted experiments using a pilot plant with in-field of the serially connected bio-activated carbon filters and hollow fiber membrane processes employed in traditional water purification plants. Results showed under low TOC conditions of humic acid in influent (0.69 to 1.03 mg TOC/L) with an EBCT of 30 min, 40 min, and 50 min, TOC removal rates increases with greater EBCT, attaining about 39 % removal rate. The removal rate of THMs and HAAs by BACF was 54.8 % and 89.0 %, respectively.