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Removal of multiple pesticides from water by different types of membranes

Seah MQ, Ng ZC, Lai GS, Lau WJ, Al-Ghouti MA, Alias NH, et al.

Chemosphere, 2024 May;356:141960.
PMID: 38604517 DOI: 10.1016/j.chemosphere.2024.141960

Pesticides are used in agriculture to protect crops from pathogens, insects, fungi and weeds, but the release of pesticides into surface/groundwater by agriculture runoff and rain has raised serious concerns not only for the environment but also for human health. This study aimed to investigate the impact of surface properties on the performance of seven distinct membrane types utilized in nanofiltration (NF), reverse osmosis (RO) and forward osmosis (FO) processes in eliminating multiple pesticides from spiked water. Out of the membranes tested, two are self-fabricated RO membranes while the rest are commercially available membranes. Our results revealed that the self-fabricated RO membranes performed better than other commercial membranes (e.g., SW30XLE, NF270, Duracid and FO) in rejecting the targeted pesticides by achieving at least 99% rejections regardless of the size of pesticides and their log Kow value. Despite the marginally lower water flux exhibited by the self-fabricated membrane compared to the commercial BW30 membrane, its exceptional ability to reject both mono- and divalent salts renders it more apt for treating water sources containing not only pesticides but also various dissolved ions. The enhanced performance of the self-fabricated RO membrane is mainly attributed to the presence of a hydrophilic interlayer (between the polyamide layer and substrate) and the incorporation of hydrophilic nanosheets in tuning its surface characteristics. The findings of the work provide insight into the importance of membrane surface modification for the application of not only the desalination process but also for the removal of contaminants of emerging concern.

Matched MeSH terms: Osmosis*
Altering substrate properties of thin film nanocomposite membrane by Al2O3 nanoparticles for engineered osmosis process

Liew ZS, Ho YC, Lau WJ, Nordin NAHM, Lai SO, Ma J

Environ Technol, 2024 Feb;45(6):1052-1065.
PMID: 36250395 DOI: 10.1080/09593330.2022.2137435

The scarcity of energy and water resources is a major challenge for humanity in the twenty-first century. Engineered osmosis (EO) technologies are extensively researched as a means of producing sustainable water and energy. This study focuses on the modification of substrate properties of thin film nanocomposite (TFN) membrane using aluminium oxide (Al2O3) nanoparticles and further evaluates the performance of resultant membranes for EO process. Different Al2O3 loading ranging from zero to 0.10 wt% was incorporated into the substrate and the results showed that the hydrophilicity of substrate was increased with contact angle reduced from 74.81° to 66.17° upon the Al2O3 incorporation. Furthermore, the addition of Al2O3 resulted in the formation of larger porous structure on the bottom part of substrate which reduced water transport resistance. Using the substrate modified by 0.02 wt% Al2O3, we could produce the TFN membrane that exhibited the highest water permeability (1.32 L/m2.h.bar, DI water as a feed solution at 15 bar), decent salt rejection (96.89%), low structural parameter (532.44 μm) and relatively good pressure withstandability (>25 bar).

Matched MeSH terms: Osmosis
Fulltext Progress of Interfacial Polymerization Techniques for Polyamide Thin Film (Nano)Composite Membrane Fabrication: A Comprehensive Review

Seah MQ, Lau WJ, Goh PS, Tseng HH, Wahab RA, Ismail AF

Polymers (Basel), 2020 Nov 27;12(12).
PMID: 33261079 DOI: 10.3390/polym12122817

In this paper, we review various novel/modified interfacial polymerization (IP) techniques for the fabrication of polyamide (PA) thin film composite (TFC)/thin film nanocomposite (TFN) membranes in both pressure-driven and osmotically driven separation processes. Although conventional IP technique is the dominant technology for the fabrication of commercial nanofiltration (NF) and reverse osmosis (RO) membranes, it is plagued with issues of low membrane permeability, relatively thick PA layer and susceptibility to fouling, which limit the performance. Over the past decade, we have seen a significant growth in scientific publications related to the novel/modified IP techniques used in fabricating advanced PA-TFC/TFN membranes for various water applications. Novel/modified IP lab-scale studies have consistently, so far, yielded promising results compared to membranes made by conventional IP technique, in terms of better filtration efficiency (increased permeability without compensating solute rejection), improved chemical properties (crosslinking degree), reduced surface roughness and the perfect embedment of nanomaterials within selective layers. Furthermore, several new IP techniques can precisely control the thickness of the PA layer at sub-10 nm and significantly reduce the usage of chemicals. Despite the substantial improvements, these novel IP approaches have downsides that hinder their extensive implementation both at the lab-scale and in manufacturing environments. Herein, this review offers valuable insights into the development of effective IP techniques in the fabrication of TFC/TFN membrane for enhanced water separation.

Matched MeSH terms: Osmosis
Reuse of dialysis reverse osmosis reject water for aquaponics and horticulture

Chang E, Lim JA, Low CL, Kassim A

J Nephrol, 2021 02;34(1):97-104.
PMID: 33394342 DOI: 10.1007/s40620-020-00903-0

BACKGROUND: Water crisis is becoming a threat to the well-being of the human population worldwide and use of water for healthcare contributes substantially to this resource depletion. Hemodialysis consumes large quantities of water. A huge volume of high purity dialysis water is required to safely perform dialysis treatment. In this process, up to 60-70% of source water is discarded. Many strategies have been suggested to promote green dialysis, and these include reuse of water, however, very few dialysis facilities have taken the preliminary steps to employ it.
METHODS: We share our experience in a developing country on an innovative reject-water reuse program combining aquaculture, hydroponic and horticulture activities. This is by far the first report on a "green dialysis" project involving aquaponics that reuse dialysis reverse osmosis (RO) reject water.
RESULTS: Our expereince suggests that reject water can be reused to promote water conservation with encouraging results. It provides a good and biosecure environment for fish breeding and vegetable farming . This project promotes a reduction in carbon footprint, a reduction in water waste, a sustainable organic food source, may lead to income generation, and provides a shared purpose and sense of pride among staff and dialysis patients.
CONCLUSIONS: Encompassing "environmental protection" practices into a hemodialysis unit can be done with relatively simple and practical steps.

Matched MeSH terms: Osmosis
Fulltext Osmo-dehydration pretreatment for drying of pumpkin slice

Lee, J.S., Lim, L.S.

International Food Research Journal, 2011;18(4):1223-1230.
MyJurnal

This study was designed to elucidate the effects of osmotic dehydration of pumpkin slice prior to hot-air drying. Response Surface Methodology (RSM) with Central Composite Design was used to investigate the influence of three variables, namely sucrose concentration (30-60˚Brix), immersion temperature (35-65˚C) and immersion time (90-120 min). These factors increased the solid gains and decreased the water activity (aw) of the sample; while the temperature and sucrose solution concentration increased the water loss (p

Matched MeSH terms: Osmosis
Economic feasibility of solar-powered reverse osmosis water desalination: a comparative systemic review

Maftouh A, El Fatni O, Bouzekri S, Rajabi F, Sillanpää M, Butt MH

Environ Sci Pollut Res Int, 2023 Jan;30(2):2341-2354.
PMID: 36380176 DOI: 10.1007/s11356-022-24116-z

Due to disparities in the allocation of rainwater and drought, extreme exploitation of groundwater reservoirs has depleted water supplies in many locations. In addition, improper disposal of domestic and industrial waste leads to poor drainage and deterioration of water quality. According to studies, desalination methods are an effective solution for treating unconventional water, i.e., sea and brackish water, and making it usable in daily life. Solar-powered desalination has recently received a great deal of attention around the world. Herein, we summarized challenges and future perspectives associated with solar-powered desalination units. Some hybrid technologies are also discussed like solar-wind desalination and RO-ED crystallizer technology in Morocco and the Middle East and North Africa (MENA) region. Previously, most experimental studies focused on the use of solar energy in traditional desalination methods such as multistage flash and multi-effect distillation. Desalination with reverse osmosis has become popular due to membrane technology improvement and benefits like high recovery ratios and low energy consumption. Furthermore, it has been seen that solar energy is less expensive than the energy obtained from traditional fuels in the MENA area. This article aims to comparatively and systematically review the economic feasibility of the use of solar photovoltaic reverse osmosis in desalination in the MENA region.

Matched MeSH terms: Osmosis
Fulltext Eco-friendly surface modification approach to develop thin film nanocomposite membrane with improved desalination and antifouling properties

Khoo YS, Lau WJ, Liang YY, Karaman M, Gürsoy M, Ismail AF

J Adv Res, 2022 Feb;36:39-49.
PMID: 35127163 DOI: 10.1016/j.jare.2021.06.011

INTRODUCTION: Nanomaterials aggregation within polyamide (PA) layer of thin film nanocomposite (TFN) membrane is found to be a common issue and can negatively affect membrane filtration performance. Thus, post-treatment on the surface of TFN membrane is one of the strategies to address the problem.
OBJECTIVE: In this study, an eco-friendly surface modification technique based on plasma enhanced chemical vapour deposition (PECVD) was used to deposit hydrophilic acrylic acid (AA) onto the PA surface of TFN membrane with the aims of simultaneously minimizing the PA surface defects caused by nanomaterials incorporation and improving the membrane surface hydrophilicity for reverse osmosis (RO) application.
METHODS: The TFN membrane was first synthesized by incorporating 0.05 wt% of functionalized titania nanotubes (TNTs) into its PA layer. It was then subjected to 15-s plasma deposition of AA monomer to establish extremely thin hydrophilic layer atop PA nanocomposite layer. PECVD is a promising surface modification method as it offers rapid and solvent-free functionalization for the membranes.
RESULTS: The findings clearly showed that the sodium chloride rejection of the plasma-modified TFN membrane was improved with salt passage reduced from 2.43% to 1.50% without significantly altering pure water flux. The AA-modified TFN membrane also exhibited a remarkable antifouling property with higher flux recovery rate (>95%, 5-h filtration using 1000 mg/L sodium alginate solution) compared to the unmodified TFN membrane (85.8%), which is mainly attributed to its enhanced hydrophilicity and smoother surface. Furthermore, the AA-modified TFN membrane also showed higher performance stability throughout 12-h filtration period.
CONCLUSION: The deposition of hydrophilic material on the TFN membrane surface via eco-friendly method is potential to develop a defect-free TFN membrane with enhanced fouling resistance for improved desalination process.

Matched MeSH terms: Osmosis
Fulltext A Review of CFD Modelling and Performance Metrics for Osmotic Membrane Processes

Toh KY, Liang YY, Lau WJ, Fimbres Weihs GA

Membranes (Basel), 2020 Oct 15;10(10).
PMID: 33076290 DOI: 10.3390/membranes10100285

Simulation via Computational Fluid Dynamics (CFD) offers a convenient way for visualising hydrodynamics and mass transport in spacer-filled membrane channels, facilitating further developments in spiral wound membrane (SWM) modules for desalination processes. This paper provides a review on the use of CFD modelling for the development of novel spacers used in the SWM modules for three types of osmotic membrane processes: reverse osmosis (RO), forward osmosis (FO) and pressure retarded osmosis (PRO). Currently, the modelling of mass transfer and fouling for complex spacer geometries is still limited. Compared with RO, CFD modelling for PRO is very rare owing to the relative infancy of this osmotically driven membrane process. Despite the rising popularity of multi-scale modelling of osmotic membrane processes, CFD can only be used for predicting process performance in the absence of fouling. This paper also reviews the most common metrics used for evaluating membrane module performance at the small and large scales.

Matched MeSH terms: Osmosis
Fulltext Vibration-assisted forward osmosis process for Mao (Antidesma bunius L. Spreng) juice concentration: water flux enhancement and preservation of phytochemicals

Sirinupong, T., Tirawat, D., Lau, W. J., Youravong, W.

International Food Research Journal, 2020;27(6):1156-1166.
MyJurnal

The experimental water flux of the forward osmosis (FO) process is much lower than the
theoretical flux due to the existence of the internal concentration polarisation (ICP), external
concentration polarisation (ECP), and membrane fouling. In the present work, vibration was
integrated with the FO process to enhance water flux in water and Mao (Antidesma bunius L.
Spreng) juice concentration. In addition, the capability of the FO process in preserving
phytochemicals was studied. The use of the vibration assisted technique could enhance the
water flux up to 23% during the FO process of distilled water due to the reduction of ICP, and
a much higher water flux enhancement (up to 70%) was attained during the FO of Mao juice
due to the reduction of ICP, ECP, and fouling. Phytochemicals including total phenolic
compounds, anthocyanin, and ascorbic acid were preserved up to 82.7, 72.6, and 95.9%,
respectively. These results suggest that membrane vibration is a promising technique for the
enhancement of the FO process performance.

Matched MeSH terms: Osmosis
Fulltext Bioadsorption of multiple heavy metal ions by rhizophora apiculate sp. and elaesis guineensis sp.

Nicodemus Ujih, M.B., Mohammad Isa Mohamadin, Millaa Armila Asli, Bebe Norlita Mohamed

Scientific Research Journal, 2017;14(1):15-27.
MyJurnal

Heavy metal ions contamination has become more serious which is caused
by the releasing of toxic waterfrom industrial area and landfill that are very
harmful to all living organism especially human and can even cause death
if contaminated in small amount of heavy metal concentration. Currently,
peoples are using classic method namely electrochemical treatment,
chemical oxidation/reduction, chemical precipitation and reverse osmosis
to eliminate the metal ions from toxic water. Unfortunately, these methods
are costly and not environmentally friendly as compared to bioadsorption
method, where agricultural waste is used as biosorbent to remove heavy
metals. Two types of agricultural waste used in this research namely oil
palm mesocarp fiber (Elaesis guineensis sp.) (OPMF) and mangrove bark
(Rhizophora apiculate sp.) (MB) biomass. Through chemical treatment,
the removal efficiency was found to improve. The removal efficiency is
examined based on four specification namely dosage, of biosorbent to
adsorb fourtypes of metalsion explicitly nickel, lead, copper, and chromium.
The research has found that the removal efficiency of MB was lower than
OPMF; whereas, the multiple metals ions removal efficiency decreased in
the order of Pb2+ > Cu2+ > Ni2+ > Cr2+.

Matched MeSH terms: Osmosis
Fulltext Application of Zwitterions in Forward Osmosis: A Short Review

Chiao YH, Sengupta A, Ang MBMY, Chen ST, Haan TY, Almodovar J, et al.

Polymers (Basel), 2021 Feb 15;13(4).
PMID: 33672026 DOI: 10.3390/polym13040583

Forward osmosis (FO) is an important desalination method to produce potable water. It was also used to treat different wastewater streams, including industrial as well as municipal wastewater. Though FO is environmentally benign, energy intensive, and highly efficient; it still suffers from four types of fouling namely: organic fouling, inorganic scaling, biofouling and colloidal fouling or a combination of these types of fouling. Membrane fouling may require simple shear force and physical cleaning for sufficient recovery of membrane performance. Severe fouling may need chemical cleaning, especially when a slimy biofilm or severe microbial colony is formed. Modification of FO membrane through introducing zwitterionic moieties on the membrane surface has been proven to enhance antifouling property. In addition, it could also significantly improve the separation efficiency and longevity of the membrane. Zwitterion moieties can also incorporate in draw solution as electrolytes in FO process. It could be in a form of a monomer or a polymer. Hence, this review comprehensively discussed several methods of inclusion of zwitterionic moieties in FO membrane. These methods include atom transfer radical polymerization (ATRP); second interfacial polymerization (SIP); coating and in situ formation. Furthermore, an attempt was made to understand the mechanism of improvement in FO performance by zwitterionic moieties. Finally, the future prospective of the application of zwitterions in FO has been discussed.

Matched MeSH terms: Osmosis
Fulltext Comparison of Pressure-Retarded Osmosis Performance between Pilot-Scale Cellulose Triacetate Hollow-fiber and Polyamide Spiral-Wound Membrane Modules

Kakihana Y, Jullok N, Shibuya M, Ikebe Y, Higa M

Membranes (Basel), 2021 Feb 28;11(3).
PMID: 33671075 DOI: 10.3390/membranes11030177

Pressure-retarded osmosis (PRO) has recently received attention because of its ability to generate power via an osmotic pressure gradient between two solutions with different salinities: high- and low-salinity water sources. In this study, PRO performance, using the two pilot-scale PRO membrane modules with different configurations-five-inch cellulose triacetate hollow-fiber membrane module (CTA-HF) and eight-inch polyamide spiral-wound membrane modules (PA-SW)-was evaluated by changing the draw solution (DS) concentration, applied hydrostatic pressure difference, and the flow rates of DS and feed solution (FS), to obtain the optimum operating conditions in PRO configuration. The maximum power density per unit membrane area of PA-SW at 0.6 M NaCl was 1.40 W/m2 and 2.03-fold higher than that of CTA-HF, due to the higher water permeability coefficient of PA-SW. In contrast, the maximum power density per unit volume of CTA-SW at 0.6 M NaCl was 4.67 kW/m3 and 6.87-fold higher than that of PA-SW. The value of CTA-HF increased to 13.61 kW/m3 at 1.2 M NaCl and was 12.0-fold higher than that of PA-SW because of the higher packing density of CTA-HF.

Matched MeSH terms: Osmosis
Fulltext Effect of osmotic dehydration process using sucrose solution at mild temperature on mass transfer and quality attributes of red pitaya (Hylocereus polyrhizusis)

Haj Najafi, A., Yusof, Y. A., Rahman, R. A., Ganjloo, A., Ling, C. N.

International Food Research Journal, 2014;21(2):625-630.
MyJurnal

In the current research, osmotic dehydration of red pitaya (Hylocereus polyrhizusis) cubes using sucrose solution at mild temperature (35ºC) was investigated. Sucrose solution (40, 50 and 60% w/w) was employed for osmotic dehydration process. Responses of weight reduction (WR), solid gain (SG), water loss (WL), color (L*, a* and b*) and texture (hardness) were evaluated. It was found that sucrose concentration significantly (p < 0.05) affected the mass transfer terms during osmosis process. The results obtained revealed an increase in yellowness (b*), decrease in lightness (L*) and redness (a*) as the sucrose concentration increased. Furthermore, osmotically dehydrated samples were considerably softer than untreated samples. Increasing of sucrose concentration and dehydration time caused softer tissue of dehydrated product compared with the fresh red pitaya.

Matched MeSH terms: Osmosis
Fulltext Anti-Fouling Double-Skinned Forward Osmosis Membrane with Zwitterionic Brush for Oily Wastewater Treatment

Ong CS, Al-Anzi B, Lau WJ, Goh PS, Lai GS, Ismail AF, et al.

Sci Rep, 2017 07 31;7(1):6904.
PMID: 28761159 DOI: 10.1038/s41598-017-07369-4

Despite its attractive features for energy saving separation, the performance of forward osmosis (FO) has been restricted by internal concentration polarization and fast fouling propensity that occur in the membrane sublayer. These problems have significantly affected the membrane performance when treating highly contaminated oily wastewater. In this study, a novel double-skinned FO membrane with excellent anti-fouling properties has been developed for emulsified oil-water treatment. The double-skinned FO membrane comprises a fully porous sublayer sandwiched between a highly dense polyamide (PA) layer for salt rejection and a fairly loose dense bottom zwitterionic layer for emulsified oil particle removal. The top dense PA layer was synthesized via interfacial polymerization meanwhile the bottom layer was made up of a zwitterionic polyelectrolyte brush - (poly(3-(N-2-methacryloxyethyl-N,N-dimethyl) ammonatopropanesultone), abbreviated as PMAPS layer. The resultant double-skinned membrane exhibited a high water flux of 13.7 ± 0.3 L/m2.h and reverse salt transport of 1.6 ± 0.2 g/m2.h under FO mode using 2 M NaCl as the draw solution and emulsified oily solution as the feed. The double-skinned membrane outperforms the single-skinned membrane with much lower fouling propensity for emulsified oil-water separation.

Matched MeSH terms: Osmosis
Design, optimisation and reliability allocation for energy systems based on equipment function and operating capacity

Andiappan V, Benjamin MFD, Tan RR, Ng DKS

Heliyon, 2019 Oct;5(10):e02594.
PMID: 31720447 DOI: 10.1016/j.heliyon.2019.e02594

Designers of energy systems often face challenges in balancing the trade-off between cost and reliability. In literature, several papers have presented mathematical models for optimizing the reliability and cost of energy systems. However, the previous models only addressed reliability implicitly, i.e., based on availability and maintenance planning. Others focused on allocation of reliability based on individual equipment requirements via non-linear models that require high computational effort. This work proposes a novel mixed-integer linear programming (MILP) model that combines the use of both input-output (I-O) modelling and linearized parallel system reliability expressions. The proposed MILP model can optimize the design and reliability of energy systems based on equipment function and operating capacity. The model allocates equipment with sufficient reliability to meet system functional requirements and determines the required capacity. A simple pedagogical example is presented in this work to illustrate the features of proposed MILP model. The MILP model is then applied to a polygeneration case study consisting of two scenarios. In the first scenario, the polygeneration system was optimized based on specified reliability requirements. The technologies chosen for Scenario 1 were the CHP module, reverse osmosis unit and vapour compression chiller. The total annualized cost (TAC) for Scenario 1 was 53.3 US$ million/year. In the second scenario, the minimum reliability level for heat production was increased. The corresponding results indicated that an additional auxiliary boiler must be operated to meet the new requirements. The resulting TAC for the Scenario 2 was 5.3% higher than in the first scenario.

Matched MeSH terms: Osmosis
Unlocking the application potential of forward osmosis through integrated/hybrid process

Ang WL, Mohammad AW, Johnson D, Hilal N

Sci Total Environ, 2020 Mar 01;706:136047.
PMID: 31864996 DOI: 10.1016/j.scitotenv.2019.136047

Study of forward osmosis (FO) has been increasing steadily over recent years with applications mainly focusing on desalination and wastewater treatment processes. The working mechanism of FO lies in the natural movement of water between two streams with different osmotic pressure, which makes it useful in concentrating or diluting solutions. FO has rarely been operated as a stand-alone process. Instead, FO processes often appear in a hybrid or integrated form where FO is combined with other treatment technologies to achieve better overall process performance and cost savings. This article aims to provide a comprehensive review on the need for hybridization/integration for FO membrane processes, with emphasis given to process enhancement, draw solution regeneration, and pretreatment for FO fouling mitigation. In general, integrated/hybrid FO processes can reduce the membrane fouling propensity; prepare the solution suitable for subsequent value-added uses and production of renewable energy; lower the costs associated with energy consumption; enhance the quality of treated water; and enable the continuous operation of FO through the regeneration of draw solution. The future potential of FO lies in the success of how it can be hybridized or integrated with other technologies to minimize its own shortcomings, while enhancing the overall performance.

Matched MeSH terms: Osmosis
Investigation of reverse ionic diffusion in forward-osmosis-aided dewatering of microalgae: A molecular dynamics study

Itliong JN, Villagracia ARC, Moreno JLV, Rojas KIM, Bernardo GPO, David MY, et al.

Bioresour Technol, 2019 May;279:181-188.
PMID: 30731357 DOI: 10.1016/j.biortech.2019.01.109

This study aimed to investigate the transport mechanisms of ions during forward-osmosis-driven (FO-driven) dewatering of microalgae using molecular dynamics (MD) simulations. The dynamical and structural properties of ions in FO systems of varying NaCl or MgCl2 draw solution (DS) concentrations were calculated and correlated. Results indicate that FO systems with higher DS concentration caused ions to have lower hydration numbers and higher coordination numbers leading to lower diffusion coefficients. The higher hydration number of Mg2+ ions resulted in significantly lower ionic permeability as compared to Na+ ions at all concentrations (p = 0.002). The simulations also revealed that higher DS concentrations led to higher accumulation of ions in the membrane. This study provides insights on the proper selection of DS for FO systems.

Matched MeSH terms: Osmosis
Low-cost silica based ceramic supported thin film composite hollow fiber membrane from guinea corn husk ash for efficient removal of microplastic from aqueous solution

Yogarathinam LT, Usman J, Othman MHD, Ismail AF, Goh PS, Gangasalam A, et al.

J Hazard Mater, 2022 02 15;424(Pt A):127298.
PMID: 34571470 DOI: 10.1016/j.jhazmat.2021.127298

In this study, an economic silica based ceramic hollow fiber (HF) microporous membrane was fabricated from guinea cornhusk ash (GCHA). A silica interlayer was coated to form a defect free silica membrane which serves as a support for the formation of thin film composite (TFC) ceramic hollow fiber (HF) membrane for the removal of microplastics (MPs) from aqueous solutions. Polyacrylonitrile (PAN), polyvinyl-chloride (PVC), polyvinylpyrrolidone (PVP) and polymethyl methacrylate (PMMA) are the selected MPs The effects of amine monomer concentration (0.5 wt% and 1 wt%) on the formation of poly (piperazine-amide) layer via interfacial polymerization over the GCHA ceramic support were also investigated. The morphology analysis of TFC GCHA HF membranes revealed the formation of a poly (piperazine-amide) layer with narrow pore arrangement. The pore size of TFC GCHA membrane declined with the formation of poly (piperazine-amide) layer, as evidenced from porosimetry analysis. The increase of amine concentration reduced the porosity and water flux of TFC GCHA HF membranes. During MPs filtration, 1 wt% (piperazine) based TFC GCHA membrane showed a lower transmission percentage of PVP (2.7%) and other suspended MPs also displayed lower transmission. The impact of humic acid and sodium alginate on MPs filtration and seawater pretreatment were also analyzed.

Matched MeSH terms: Osmosis
Optimization of osmotic dehydration of Terung Asam (Solanum lasiocarpum Dunal)

Chiu MT, Tham HJ, Lee JS

J Food Sci Technol, 2017 Sep;54(10):3327-3337.
PMID: 28974818 DOI: 10.1007/s13197-017-2785-3

This study was designed to determine the effect of osmotic dehydration (OD) process temperature (35-55 °C), sucrose concentration (40-60% w/w) and immersion time (90-210 min) on the water loss (WL), solid gain (SG), DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP) and sensory quality of the dehydrated Terung Asam slices. Response Surface Methodology with Central Composite Design was applied to investigate the influence of these variables on the aforementioned responses. The increase in the levels of these processing parameters increased the WL and SG. The antioxidant activities also increased with sugar concentration, but reduced with immersion time and temperature elevation. About 36-80% of IC50 and 47-72% of FRAP were depleted after osmotic process. The loss of antioxidants was predominantly due to leaching during osmotic treatment rather than hot air drying. Despite the losses of these compounds, osmotic pretreatment was able to improve the sensory quality of the product. The optimum OD process condition was predicted as process temperature 38.1 °C, sucrose concentration 55.6% and osmotic duration 126.3 min.

Matched MeSH terms: Osmosis
Application of immersed MF (IMF) followed by reverse osmosis (RO) membrane for wastewater reclamation: A case study in Malaysia

Ujang Z, Ng KS, Tg Hamzah TH, Roger P, Ismail MR, Shahabudin SM, et al.

Water Sci Technol, 2007;56(9):103-8.
PMID: 18025737

A pilot scale membrane plant was constructed and monitored in Shah Alam, Malaysia for municipal wastewater reclamation for industrial application purposes. The aim of this study was to verify its suitability under the local conditions and environmental constraints for secondary wastewater reclamation. Immersed-type crossflow microfiltration (IMF) was selected as the pretreatment step before reverse osmosis filtration. Secondary wastewater after chlorine contact tank was selected as feed water. The results indicated that the membrane system is capable of producing a filtrate meeting the requirements of both WHO drinking water standards and Malaysian Effluent Standard A. With the application of an automatic backwash process, IMF performed well in hydraulic performance with low fouling rate being achieved. The investigations showed also that chemical cleaning is still needed because of some irreversible fouling by microorganisms always remains. RO treatment with IMF pretreatment process was significantly applicable for wastewater reuse purposes and promised good hydraulic performance.

Matched MeSH terms: Osmosis

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