Displaying publications 61 - 80 of 177 in total

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  1. Hussain A, Farrukh S, Hussain A, Ayoub M
    Environ Technol, 2019 Mar;40(7):843-854.
    PMID: 29161995 DOI: 10.1080/09593330.2017.1408696
    Most of the polymers and their blends, utilized in carbon capture membranes, are costly, but cellulose acetate (CA) being inexpensive is a lucrative choice. In this research, pure and mixed matrix membranes (MMMs) have been fabricated to capture carbon from natural gas. Polyethylene glycol (PEG) has been utilized in the fabrication of membranes to modify the chain flexibility of polymers. Multi-walled carbon nanotubes (MWCNTs) provide mechanical strength, thermal stability, an extra free path for CO2 molecules and augment CO2/CH4 selectivity. Membranes of pure CA, CA/PEG blend of different PEG concentrations (5%, 10%, 15%) and CA/PEG/MWCNTs blend of 10% PEG with different MWCNTs concentrations (5%, 10%, 15%) were prepared in acetone using solution casting techniques. Fabricated membranes were characterized using SEM, TGA and tensile testing. Permeation results revealed remarkable improvement in CO2/CH4 selectivity. In single gas experiments, CO2/CH4 selectivity is enhanced 8 times for pure membranes containing 10% PEG and 14 times for MMMs containing 10% MWCNTs. In mix gas experiments, the CO2/CH4 selectivity is increased 13 times for 10% PEG and 18 times for MMMs with 10% MWCNTs. Fabricated MMMs have a tensile strength of 13 MPa and are more thermally stable than CA membranes.
    Matched MeSH terms: Membranes, Artificial
  2. Daud SM, Noor ZZ, Mutamim NSA, Baharuddin NH, Aris A
    Environ Sci Pollut Res Int, 2023 Aug;30(40):91636-91648.
    PMID: 37518846 DOI: 10.1007/s11356-023-28975-y
    A conventional activated sludge (CAS) system has traditionally been used for secondary treatment in wastewater treatment plants. Due to the high cost of aeration and the problem of sludge treatment, researchers are developing alternatives to the CAS system. A membrane bioreactor (MBR) is a technology with higher solid-liquid separation efficiency. However, the use of MBR is limited due to inevitable membrane fouling and high energy consumption. Membrane fouling requires frequent cleaning, and MBR components must be replaced, which reduces membrane lifetime and operating costs. To overcome the limitations of the MBR system, a microbial fuel cell-membrane bioreactor (MFC-MBR) coupling system has attracted the interest of researchers. The design of the novel bioelectrochemical membrane reactor (BEMR) can effectively couple microbial degradation in the microbial electrochemical system (MES) and generate a microelectric field to reduce and alleviate membrane fouling in the MBR system. In addition, the coupling system combining an MES and an MBR can improve the efficiency of COD and ammonium removal while generating electricity to balance the energy consumption of the system. However, several obstacles must be overcome before the MFC-MBR coupling system can be commercialised. The aim of this study is to provide critical studies of the MBR, MES and MFC-MBR coupling system for wastewater treatment. This paper begins with a critical discussion of the unresolved MBR fouling problem. There are detailed past and current studies of the MES-MBR coupling system with comparison of performances of the system. Finally, the challenges faced in developing the coupling system on a large scale were discussed.
    Matched MeSH terms: Membranes, Artificial
  3. Daud SM, Kim BH, Ghasemi M, Daud WR
    Bioresour Technol, 2015 Nov;195:170-9.
    PMID: 26141668 DOI: 10.1016/j.biortech.2015.06.105
    Microbial electrochemical technologies (METs) are emerging green processes producing useful products from renewable sources without causing environmental pollution and treating wastes. The separator, an important part of METs that greatly affects the latter's performance, is commonly made of Nafion proton exchange membrane (PEM). However, many problems have been identified associated with the Nafion PEM such as high cost of membrane, significant oxygen and substrate crossovers, and transport of cations other than protons protons and biofouling. A variety of materials have been offered as alternative separators such as ion-exchange membranes, salt bridges, glass fibers, composite membranes and porous materials. It has been claimed that low cost porous materials perform better than PEM. These include J-cloth, nylon filter, glass fiber mat, non-woven cloth, earthen pot and ceramics that enable non-ion selective charge transfer. This paper provides an up-to-date review on porous separators and plots directions for future studies.
    Matched MeSH terms: Membranes, Artificial
  4. Le-Clech P, Alvarez-Vazquez H, Jefferson B, Judd S
    Water Sci Technol, 2003;48(3):113-9.
    PMID: 14518862
    As with all membrane processes, turbulence, as promoted by aeration in submerged membrane bioreactors (MBRs) or pumping in sidestream (SS) systems to produce somewhat higher effective cross-flow velocities, increases mass transfer and reduces fouling. This is manifested in an elevated critical flux, the flux at which the membrane permeability is sustained. However, the non-Newtonian nature of the sludge makes precise rheological characterisation difficult. In this study, a calculation of the appropriate hydrodynamics parameters for a SS MBR configuration is presented. Optimisation of the aeration in a submerged MBR system has been attained by defining the minimum air velocity required for Taylor bubble formation.
    Matched MeSH terms: Membranes, Artificial
  5. Shamel MM, Sulaiman NM, Sulaiman MZ
    Artif Cells Blood Substit Immobil Biotechnol, 1999 Sep-Nov;27(5-6):447-53.
    PMID: 10595447
    A study was conducted to evaluate the cross flow tubular ultrafiltration behavior of aqueous solutions of pectin. The effectiveness of pulsatile flow as a cleaning-in-place (CIP) technique to improve permeate flux was undertaken on the above mentioned solution. This investigation is part of a study to apply membrane filtration in the clarification of tropical fruit juice. The main variables, which were investigated, include the concentration of pectin, pulse frequency and amplitude. It was found that the amount of pectin in the solution significantly affects its ultrafiltration behavior. From the observed profiles, it is evident that the formation of gel layer on the membrane surface is responsible for the leveling of flux at high pressures. The presence of pectin was found to affect the properties of the solution such as viscosity, pH and the size of pectin colloid. Improvements in the permeate flux for pectin solution were obtained by employing pulsatile flow cleaning-in-place technique. Both pulse frequency and amplitude are important parameters that can improve the improvement of in-situ cleaning method. Similar to several findings reported in the literature, pulsatile flow showed significant effectiveness of about 60% higher flux when the ultrafiltration process is operated under laminar condition.
    Matched MeSH terms: Membranes, Artificial
  6. Saad B, Bee-Leng Y, Saleh MI, Rahman IA, Mansor SM
    J AOAC Int, 2001 8 15;84(4):1151-7.
    PMID: 11501917
    Potentiometric response characteristics were evaluated for quinine selective sensors based on a lipophilic ion-exchanger potassium tetrakis[3,5-bis(trifluoromethylphenyl)]borate (PTFB) immobilized together with plasticizing solvents in polyvinyl chloride membranes. The use of dioctyl phthalate (DOP), 2-nitrophenyl phenyl ether (NPPE), and bis(2-ethylhexyl)adipate (BEHA) plasticizers produced good quality quinine sensors that were sensitive and fast responding, and exhibited near Nernstian responses when used as batch-sensors. These membranes were further tested in a wall-jet flow-through potentiometric flow injection analysis (FIA) detector. Quinine sensors containing BEHA were the most suitable membrane, with no noticeable differences in sensitivity even after 5 h of continuous exposure to solutions. Interference by foreign species such as alkali, alkaline earth metal ions, sugars, and sodium benzoate was minimal in either the batch-mode (log selectivity coefficients
    Matched MeSH terms: Membranes, Artificial
  7. Shishegaran A, Boushehri AN, Ismail AF
    J Environ Manage, 2020 Jun 15;264:110444.
    PMID: 32217322 DOI: 10.1016/j.jenvman.2020.110444
    Surfactants are the emerging contaminant and cause a detrimental effect on the ecosystem. In this study, an attempt is made to removal anionic surfactant Sodium dodecyl sulfate (SDS) containing wastewater using hydrophilic polyvinylpyrollidone (PVP) (5-15 wt%) modified polyethersulfone (PES) ultrafiltration membrane. The influence of operating variables on membrane performance was also sequentially analyzed using tests and three numerical modeling methods such as multiple linear regression (MLR), multiple Ln-equation regression (MLnER), and gene expression programming (GEP). Contact angle value of 10 wt% PVP modified PES membrane decreased up to 23.8°, whereas the neat PES membrane is 70.7°. This study indicates that the required hydrophilic property was improved in the modified membrane. The water flux and porosity also enhanced in PVP modified PES membranes. In performance evaluation, the optimum operating variable condition of transmembrane pressure (TMP), feed concentration, and the temperature is found to be 3 bar, 100 ppm, and 25 °C, respectively. Among the models, GEP has a good correlation with experimental anionic surfactant SDS filtration data. GEP performs better than other model with respect to statistical parameter and error terms. This study provides an insight into an adaptation of novel numerical modeling methods for the prediction of membrane performance to the treatment of surfactant wastewater.
    Matched MeSH terms: Membranes, Artificial
  8. Lee EH, Lim SS, Yuen KH, Lee CY
    J Pharm Pharmacol, 2019 May;71(5):860-868.
    PMID: 30515807 DOI: 10.1111/jphp.13052
    OBJECTIVES: This study aims to investigate the blood-brain barrier (BBB) permeability of curcumin analogues with shortened linkers and their ability to protect against amyloid-beta toxicity in a whole organism model.

    METHOD: Four curcumin analogues were synthesized. These analogues and curcumin were evaluated for their BBB permeability in the parallel artificial membrane permeability assay. The transgenic Caenorhabditis elegansGMC101 that expresses human Aβ1-42 was treated with the compounds to evaluate their ability to delay Aβ-induced paralysis. Expression of skn-1mRNA was examined on nematodes treated with selected efficacious compounds. In vitro Aβ aggregation in the presence of the compounds was performed.

    KEY FINDINGS: The four analogues showed improved BBB permeability vs curcumin in the PAMPA with the hemi-analogue C4 having the highest permeability coefficient. At 100 μm, analogues C1 and C4 as well as curcumin significantly prolonged the survival of the nematodes protecting against Aβ toxicity. However, only curcumin and C4 showed protection at lower concentrations. skn-1mRNA was significantly elevated in nematodes treated with curcumin and C4 indicating SKN-1/Nrf activation as a possible mode of action.

    CONCLUSIONS: Analogue C4 provides a new lead for the development of a curcumin-based compound for protection against Aβ toxicity with an improved BBB permeability.

    Matched MeSH terms: Membranes, Artificial
  9. Moideen SNF, Krishnan S, Li YY, Hassim MH, Kamyab H, Nasrullah M, et al.
    Chemosphere, 2023 Mar;317:137923.
    PMID: 36682635 DOI: 10.1016/j.chemosphere.2023.137923
    An anaerobic membrane bioreactor (AnMBR) was employed as primary treatment unit for anaerobic treatment of simulated wastewater to produce high effluent quality. A lab scale hollow fiber membrane was used to scrutinize the performance of AnMBR as a potential treatment system for simulated milk wastewater and analyze its energy recovery potential. The 15 L bioreactor was operated continuously at mesophilic conditions (35 °C) with a pH constant of 7.0. The membrane flux was in the range of 9.6-12.6 L/m2. h. The different organic loading rates (OLRs) of 1.61, 3.28, 5.01, and 8.38 g-COD/L/d, of simulated milk wastewater, were fed to the reactor and the biogas production rate was analyzed, respectively. The results revealed that the COD removal efficiencies of 99.54 ± 0.001% were achieved at the OLR of 5.01 gCOD/L/d. The highest methane yield was found to be at OLR of 1.61 gCOD/L/d at HRT of 30 d with the value of 0.33 ± 0.01 L-CH4/gCOD. Moreover, based on the analysis of energy balance in the AnMBR system, it was found that energy is positive at all the given HRTs. The net energy production (NEP) ranged from 2.594 to 3.268 kJ/gCOD, with a maximum NEP value of 3.268 kJ/gCOD at HRT 10 d HRT. Bioenergy recovery with the maximum energy ratio, of 4.237, was achieved with an HRT of 5 d. The study suggests a sizable energy saving with the anaerobic membrane process.
    Matched MeSH terms: Membranes, Artificial
  10. Suresh Y, Azil AH, Abdullah SR
    PLoS One, 2024;19(1):e0295961.
    PMID: 38252615 DOI: 10.1371/journal.pone.0295961
    In some laboratories, mosquitoes' direct blood-feeding on live animals has been replaced with various membrane blood-feeding systems. The selection of blood meal sources used in membrane feeding is crucial in vector mass rearing as it influences the mosquitoes' development and reproductive fitness. Therefore, this scoping review aimed to evaluate the existing literature on the use of different blood sources and components in artificial membrane feeding systems and their effects on blood-feeding and the fecundity rate of Ae. aegypti. A literature review search was conducted by using PubMed, Scopus, and Web of Science databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA-ScR). The EndNote version 20 software was used to import all searched articles. Relevant information was retrieved for analysis into a Microsoft Excel Spreadsheet. A total of 104 full-text articles were assessed for eligibility criteria, whereby the articles should include the comparison between different types of blood source by using the membrane feeding systems. Only 16 articles were finally included in the analysis. Several studies had reported that human blood was superior in blood-feeding Ae. aegypti as compared to sheep blood which resulted in lower fecundity due to accumulation of free fatty acids (FFA) in the cuticles. In contrast, cattle whole blood and pig whole blood showed no significant differences in the blood-feeding and fecundity rate as compared to human blood. This review also indicated that bovine whole blood and pig whole blood enhanced Ae. aegypti's vitellogenesis and egg production as compared to plasma and blood cells. In addition, human blood of up to 10 days after the expiration date could still be used to establish Ae. aegypti colonies with good blood-feeding rates and number of eggs produced. Thus, future studies must consider the importance of selecting suitable blood sources and components for membrane blood feeding especially in mosquito colonisation and control measure studies.
    Matched MeSH terms: Membranes, Artificial
  11. Suah FB, Ahmad M, Heng LY
    PMID: 25748985 DOI: 10.1016/j.saa.2015.02.068
    A novel approach for the determination of Al(3+) from aqueous samples was developed using an optode membrane produced by physical inclusion of Al(3+) selective reagent, which is morin into a plasticized poly(vinyl chloride). The inclusion of Triton X-100 was found to be valuable and useful for enhancing the sorption of Al(3+) ions from liquid phase into the membrane phase, thus increasing the intensity of optode's absorption. The optode showed a linear increase in the absorbance at λ(max)=425 nm over the concentration range of 1.85×10(-6)-1.1×10(-4) mol L(-1) (0.05-3 μg mL(-1)) of Al(3+) ions in aqueous solution after 5 min. The limit of detection was determined to be 1.04×10(-6) mol L(-1) (0.028 μg mL(-1)). The optode developed in the present work was easily prepared and found to be stable, has good mechanical strength, sensitive and reusable. In addition, the optode was tested for Al(3+) determination in lake water, river water and pharmaceutical samples, which the result was satisfactory.
    Matched MeSH terms: Membranes, Artificial*
  12. Burham N, Hamzah AA, Majlis BY
    Biomed Mater Eng, 2014;24(6):2203-9.
    PMID: 25226919 DOI: 10.3233/BME-141032
    This paper studies parameters which affect the pore size diameter of a silicon membrane. Electrochemical etching is performed in characterise the parameter involved in this process. The parameter has been studied is volume ratio of hydrofluoric acid (HF) and ethanol as an electrolyte aqueous for electrochemical etch. This electrolyte aqueous solution has been mixed between HF and ethanol with volume ratio 3:7, 5:5, 7:3 and 9:1. As a result, the higher volume of HF in this electrolyte gives the smallest pore size diameter compared to the lower volume of HF. These samples have been dipped into HF and ethanol electrolyte aqueous with supplied 25 mA/cm2 current density for 20, 30, 40, and 50 minutes. The samples will inspect under Scanning Electron Microscope (SEM) to execute the pore formations on silicon membrane surface.
    Matched MeSH terms: Membranes, Artificial*
  13. Gan S, Zakaria S, Chia CH, Kaco H, Padzil FN
    Carbohydr Polym, 2014 Jun 15;106:160-5.
    PMID: 24721064 DOI: 10.1016/j.carbpol.2014.01.076
    Cellulose carbamate (CCs) was produced from kenaf core pulp (KCP) using microwave reactor-assisted method. The effects of urea concentration and reaction time on the formation of nitrogen content in CCs were investigated. The CCs' solubility in LiOH/urea system was determined and its membranes were characterized. As the urea content and reaction time increased, the nitrogen content form in CCs increased which enhanced the CCs' solubility. The formation of CCs was confirmed by Fourier transform infrared spectroscopy (FT-IR) and nitrogen content analysis. The CCs' morphology was examined using Scanning electron microscopy (SEM). The cellulose II and crystallinity index of the membranes were confirmed by X-ray diffraction (XRD). The pore size of the membrane displayed upward trend with respect to the urea content observed under Field emission scanning electron microscope (FESEM). This investigation provides a simple and efficient procedure of CCs determination which is useful in producing environmental friendly regenerated CCs.
    Matched MeSH terms: Membranes, Artificial*
  14. Asman S, Yusof NA, Abdullah AH, Haron MJ
    Molecules, 2012 Feb 15;17(2):1916-28.
    PMID: 22337139 DOI: 10.3390/molecules17021916
    This work reports the synthesis and characterization of a hybrid molecularly imprinted polymer (MIP) membrane for removal of methylene blue (MB) in an aqueous environment. MB-MIP powders were hybridized into a polymer membrane (cellulose acetate (CA) and polysulfone (PSf)) after it was ground and sieved (using 90 µm sieve). MB-MIP membranes were prepared using a phase inversion process. The MB-MIP membranes were characterized using Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscope (SEM). Parameters investigated for the removal of MB by using membrane MB-MIP include pH, effect of time, concentration of MB, and selectivity studies. Maximum sorption of MB by PSf-MB-MIP membranes and CA-MB-MIP membranes occurred at pH 10 and pH 12, respectively. The kinetic study showed that the sorption of MB by MB-MIP membranes (PSf-MB-MIP and CA-MB-MIP) followed a pseudo-second-order-model and the MB sorption isotherm can be described by a Freundlich isotherm model.
    Matched MeSH terms: Membranes, Artificial*
  15. Damayanti A, Ujang Z, Salim MR, Olsson G
    Water Sci Technol, 2011;63(8):1701-6.
    PMID: 21866771
    Biofouling is a crucial factor in membrane bioreactor (MBR) applications, particularly for high organic loading operations. This paper reports a study on biofouling in an MBR to establish a relationship between critical flux, Jc, mixed liquor suspended solids (MLSS) (ranging from 5 to 20 g L-1) and volumetric loading rate (6.3 kg COD m-3 h-1) of palm oil mill effluent (POME). A lab-scale 100 L hybrid MBR consisting of anaerobic, anoxic, and aerobic reactors was used with flat sheet microfiltration (MF) submerged in the aerobic compartment. The food-to-microorganism (F/M) ratio was maintained at 0.18 kg COD kg-1 MLSSd-1. The biofouling tendency of the membrane was obtained based on the flux against the transmembrane pressure (TMP) behaviour. The critical flux is sensitive to the MLSS. At the MLSS 20 g L-1 the critical flux is about four times lower than that for the MLSS concentration of 5 g L-1. The results showed high removal efficiency of denitrification and nitrification up to 97% at the MLSS concentration 20 g L-1. The results show that the operation has to compromise between a high and a low MLSS concentration. The former will favour a higher removal rate, while the latter will favour a higher critical flux.
    Matched MeSH terms: Membranes, Artificial*
  16. Othman N, Zailani SN, Mili N
    J Hazard Mater, 2011 Dec 30;198:103-12.
    PMID: 22023906 DOI: 10.1016/j.jhazmat.2011.10.014
    The extraction of Red 3BS reactive dye from aqueous solution was studied using emulsion liquid membrane (ELM). ELM is one of the processes that have very high potential in treating industrial wastewater consisting of dyes. In this research, Red 3BS reactive dye was extracted from simulated wastewater using tridodecylamine (TDA) as the carrier agent, salicyclic acid (SA) to protonate TDA, sodium chloride as the stripping agent, kerosene as the diluent and SPAN 80 as emulsifier. Experimental parameters investigated were salicyclic acid concentration, extraction time, SPAN 80 concentration, sodium chloride concentration, TDA concentration, agitation speed, homogenizer speed, emulsifying time and treat ratio. The results show almost 100% of Red 3BS was removed and stripped in the receiving phase at the optimum condition in this ELM system. High voltage coalesce was applied to break the emulsion hence, enables recovery of Red 3BS in the receiving phase.
    Matched MeSH terms: Membranes, Artificial*
  17. Walter JK, Jin Z, Jornitz MW, Gorrschalk U
    Methods Biochem Anal, 2011;54:281-317.
    PMID: 21954783
    Matched MeSH terms: Membranes, Artificial*
  18. Baroutian S, Aroua MK, Raman AA, Sulaiman NM
    Bioresour Technol, 2011 Jan;102(2):1095-102.
    PMID: 20888219 DOI: 10.1016/j.biortech.2010.08.076
    In this study, a novel continuous reactor has been developed to produce high quality methyl esters (biodiesel) from palm oil. A microporous TiO2/Al2O3 membrane was packed with potassium hydroxide catalyst supported on palm shell activated carbon. The central composite design (CCD) of response surface methodology (RSM) was employed to investigate the effects of reaction temperature, catalyst amount and cross flow circulation velocity on the production of biodiesel in the packed bed membrane reactor. The highest conversion of palm oil to biodiesel in the reactor was obtained at 70 °C employing 157.04 g catalyst per unit volume of the reactor and 0.21 cm/s cross flow circulation velocity. The physical and chemical properties of the produced biodiesel were determined and compared with the standard specifications. High quality palm oil biodiesel was produced by combination of heterogeneous alkali transesterification and separation processes in the packed bed membrane reactor.
    Matched MeSH terms: Membranes, Artificial*
  19. Fakhru'l-Razi A, Pendashteh A, Abidin ZZ, Abdullah LC, Biak DR, Madaeni SS
    Bioresour Technol, 2010 Sep;101(18):6942-9.
    PMID: 20434905 DOI: 10.1016/j.biortech.2010.04.005
    Oil and gas field wastewater or produced water is a significant waste stream in the oil and gas industries. In this study, the performance of a membrane sequencing batch reactor (MSBR) and membrane sequencing batch reactor/reverse osmosis (MSBR/RO) process treating produced wastewater were investigated and compared. The MSBR was operated in different hydraulic residence time (HRT) of 8, 20 and 44 h. Operation results showed that for a HRT of 20 h, the combined process effluent chemical oxygen demand (COD), total organic carbon (TOC) and oil and grease (O&G) removal efficiencies were 90.9%, 92% and 91.5%, respectively. The MSBR effluent concentration levels met the required standard for oil well re-injection. The RO treatment reduced the salt and organic contents to acceptable levels for irrigation and different industrial re-use. Foulant biopsy demonstrated that the fouling on the membrane surface was mainly due to inorganic (salts) and organic (microorganisms and their products, hydrocarbon constituents) matters.
    Matched MeSH terms: Membranes, Artificial*
  20. Siar CH, Toh CG, Romanos G, Ng KH
    Clin Oral Implants Res, 2011 Jan;22(1):113-20.
    PMID: 20678135 DOI: 10.1111/j.1600-0501.2010.01970.x
    collagenous and noncollagenous membranes have been investigated in many animal systems but their effects in the macaque model are unknown.
    Matched MeSH terms: Membranes, Artificial*
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