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Fulltext One-step synthesis of zwitterionic graphene oxide nanohybrid: Application to polysulfone tight ultrafiltration hollow fiber membrane

Syed Ibrahim GP, Isloor AM, Ismail AF, Farnood R

Sci Rep, 2020 04 23;10(1):6880.
PMID: 32327672 DOI: 10.1038/s41598-020-63356-2

In this paper, novel zwitterionic graphene oxide (GO) nanohybrid was synthesized using monomers [2-(Methacryloyloxy)ethyl]dimethyl-(3-sulfopropyl)ammonium hydroxide (SBMA) and N,N'-methylenebis(acrylamide) (MBAAm) (GO@poly(SBMA-co-MBAAm), and incorporated into polysulfone (PSF) hollow fiber membrane for the effectual rejection of dye from the wastewater. The synthesized nanohybrid was characterized using FT-IR, PXRD, TGA, EDX, TEM and zeta potential analysis. The occurrence of nanohybrid on the membrane matrix and the elemental composition were analyzed by XPS. The as-prepared tight ultrafiltration hollow fiber membrane exhibited high rejection of reactive black 5 (RB-5, 99%) and reactive orange 16 (RO-16, 74%) at a dye concentration of 10 ppm and pure water flux (PWF) of 49.6 L/m2h. Fabricated nanocomposite membranes were also studied for their efficacy in the removal of both monovalent (NaCl) and divalent salts (Na2SO4). The results revealed that the membrane possesses complete permeation to NaCl with less rejection of Na2SO4 (<5%). In addition, the nanocomposite membrane revealed outstanding antifouling performance with the flux recovery ratio (FRR) of 73% towards bovine serum albumin (BSA). Therefore, the in-house prepared novel nanocomposite membrane is a good candidate for the effective decolorization of wastewater containing dye.

Matched MeSH terms: Ultrafiltration
Gene expression programming for process parameter optimization during ultrafiltration of surfactant wastewater using hydrophilic polyethersulfone membrane

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: Ultrafiltration*
Fulltext Two-Step Dopamine-to-Polydopamine Modification of Polyethersulfone Ultrafiltration Membrane for Enhancing Anti-Fouling and Ultraviolet Resistant Properties

Mulyati S, Muchtar S, Arahman N, Syamsuddin Y, Mat Nawi NI, Yub Harun N, et al.

Polymers (Basel), 2020 Sep 09;12(9).
PMID: 32916778 DOI: 10.3390/polym12092051

Polydopamine has been widely used as an additive to enhance membrane fouling resistance. This study reports the effects of two-step dopamine-to-polydopamine modification on the permeation, antifouling, and potential anti-UV properties of polyethersulfone (PES)-based ultrafiltration membranes. The modification was performed through a two-step mechanism: adding the dopamine additive followed by immersion into Tris-HCl solution to allow polymerization of dopamine into polydopamine (PDA). The results reveal that the step of treatment, the concentration of dopamine in the first step, and the duration of dipping in the Tris solution in the second step affect the properties of the resulting membranes. Higher dopamine loadings improve the pure water flux (PWF) by more than threefold (15 vs. 50 L/m2·h). The extended dipping period in the Tris alkaline buffer leads to an overgrowth of the PDA layer that partly covers the surface pores which lowers the PWF. The presence of dopamine or polydopamine enhances the hydrophilicity due to the enrichment of hydrophilic catechol moieties which leads to better anti-fouling. Moreover, the polydopamine film also improves the membrane resistance to UV irradiation by minimizing photodegradation's occurrence.

Matched MeSH terms: Ultrafiltration
Rapid Surface Modification of Ultrafiltration Membranes for Enhanced Antifouling Properties

Said N, Khoo YS, Lau WJ, Gürsoy M, Karaman M, Ting TM, et al.

Membranes (Basel), 2020 Dec 07;10(12).
PMID: 33297433 DOI: 10.3390/membranes10120401

In this work, several ultrafiltration (UF) membranes with enhanced antifouling properties were fabricated using a rapid and green surface modification method that was based on the plasma-enhanced chemical vapor deposition (PECVD). Two types of hydrophilic monomers-acrylic acid (AA) and 2-hydroxyethyl methacrylate (HEMA) were, respectively, deposited on the surface of a commercial UF membrane and the effects of plasma deposition time (i.e., 15 s, 30 s, 60 s, and 90 s) on the surface properties of the membrane were investigated. The modified membranes were then subjected to filtration using 2000 mg/L pepsin and bovine serum albumin (BSA) solutions as feed. Microscopic and spectroscopic analyses confirmed the successful deposition of AA and HEMA on the membrane surface and the decrease in water contact angle with increasing plasma deposition time strongly indicated the increase in surface hydrophilicity due to the considerable enrichment of the hydrophilic segment of AA and HEMA on the membrane surface. However, a prolonged plasma deposition time (>15 s) should be avoided as it led to the formation of a thicker coating layer that significantly reduced the membrane pure water flux with no significant change in the solute rejection rate. Upon 15-s plasma deposition, the AA-modified membrane recorded the pepsin and BSA rejections of 83.9% and 97.5%, respectively, while the HEMA-modified membrane rejected at least 98.5% for both pepsin and BSA. Compared to the control membrane, the AA-modified and HEMA-modified membranes also showed a lower degree of flux decline and better flux recovery rate (>90%), suggesting that the membrane antifouling properties were improved and most of the fouling was reversible and could be removed via simple water cleaning process. We demonstrated in this work that the PECVD technique is a promising surface modification method that could be employed to rapidly improve membrane surface hydrophilicity (15 s) for the enhanced protein purification process without using any organic solvent during the plasma modification process.

Matched MeSH terms: Ultrafiltration
Fulltext Investigation of Anti-fouling and UV-Cleaning Properties of PVDF/TiO2 Mixed-Matrix Membrane for Humic Acid Removal

Teow YH, Ooi BS, Ahmad AL, Lim JK

Membranes (Basel), 2020 Dec 24;11(1).
PMID: 33374274 DOI: 10.3390/membranes11010016

Natural organic matters (NOMs) have been found to be the major foulant in the application of ultrafiltration (UF) for treating surface water. Against this background, although hydrophilicity has been demonstrated to aid fouling mitigation, other parameters such as membrane surface morphology may contribute equally to improved fouling resistance. In this work, with humic acid solution as the model substance, the effects of titanium dioxides (TiO2) types (PC-20, P25, and X500) on membrane anti-fouling and defouling properties were comparatively analysed. The aims are (1) to determine the correlation between membrane surface morphology and membrane fouling and (2) to investigate the anti-fouling and UV-cleaning abilities of PVDF/TiO2 mixed-matrix membranes with different membrane topographies and surface energy conditions. The mixed-matrix membrane with P25 TiO2 exhibited the most significant UV-defouling ability, with a high irreversible flux recovery ratio (IFRR(UV)) of 16.56 after 6 h of UV irradiation, whereas that with X500 TiO2 exhibited both superior anti-fouling and defouling properties due to its smoother surface and its highly reactive surface layer.

Matched MeSH terms: Ultrafiltration
Fulltext Comparative Study of The Yield and Physicochemical Properties of Collagen from Sea Cucumber (Holothuria scabra), Obtained through Dialysis and the Ultrafiltration Membrane

Saallah S, Roslan J, Julius FS, Saallah S, Mohamad Razali UH, Pindi W, et al.

Molecules, 2021 Apr 28;26(9).
PMID: 33924820 DOI: 10.3390/molecules26092564

Collagen was extracted from the body wall of sea cucumber (Holothuria scabra) using the pepsin-solubilized collagen method followed by isolation using dialysis and the ultrafiltration membrane. The yield and physicochemical properties of the collagen obtained from both isolation methods, denoted as D-PSC and UF-PSC, were compared. The ultrafiltration method affords a higher yield of collagen (11.39%) than that of the dialysis (5.15%). The isolated collagens have almost the same amino acid composition, while their functional groups, referred to as amide A, B, I, II, and III bands, were in accordance with commercial collagen, as verified by Fourier Transform Infrared (FT-IR) spectroscopy. The UV-Vis absorption peaks at 240 nm and 220 nm, respectively, indicated that the collagens produced are type-I collagen. The D-PSC showed interconnecting sheet-like fibrils, while the UF-PSC exhibited a flaky structure with flat-sheets arranged very close to each other. The higher yield and comparable physicochemical properties of the collagen obtained by ultrafiltration as compared with dialysis indicate that the membrane process has high potential to be used in large-scale collagen production for food and pharmaceutical applications.

Matched MeSH terms: Ultrafiltration
Clinical effectiveness of a Malaysian-manufactured CAPD product: A randomised trial

Mak WY, Leong CT, Ong LM, Bavanandan S, Mushahar L, Goh BL, et al.

Perit Dial Int, 2021 05;41(3):273-283.
PMID: 33733911 DOI: 10.1177/0896860821993954

BACKGROUND: We compared the clinical effectiveness of a new peritoneal dialysis (PD) product with polyvinyl chloride-containing tubing (Stay Safe Link®, SSL) with the plastic-free alternative (Stay Safe®, STS) in patients on continuous ambulatory peritoneal dialysis (CAPD).
METHOD: A multicentre, parallel, randomised, controlled, open-label, non-inferiority trial was conducted. Adult patients receiving CAPD were randomised in a 1:1 ratio to SSL or STS. The primary outcome was the rate of peritonitis after 1 year of follow-up.
RESULTS: A total of 472 subjects were randomised (SSL, n = 233; STS, n = 239). One subject in each group was excluded from the analysis as they withdrew consent before the first dialysis dose. Four hundred and seventy subjects (SSL, n = 232; STS, n = 238) were included in the modified intention-to-treat analysis. Non-inferiority between two groups was established as no significant difference was found in peritonitis rate (incident rate ratio: 0.91, 95% CI: 0.65-1.28). No significant difference was detected in weekly Kt/V (p = 0.58) and creatinine clearance (p = 0.55). However, the average ultrafiltration volume was significantly lower in SSL, with a mean difference of 93 ml (p < 0.01). SSL also demonstrated a 2.57-times higher risk of device defect than STS (95% CI: 1.77-3.75).
CONCLUSION: SSL was non-inferior in peritonitis rate compared to plastic-free STS over 1 year in patients requiring CAPD. There was no difference in the delivered dialysis dose, but there was a higher rate of device defects with SSL.

Matched MeSH terms: Ultrafiltration
Parametric analysis of lignocellulosic ultrafiltration in lab scale cross flow module using pore blocking and artificial neural network model

Yogarathinam LT, Velswamy K, Gangasalam A, Ismail AF, Goh PS, Subramaniam MN, et al.

Chemosphere, 2022 Jan;286(Pt 3):131822.
PMID: 34416593 DOI: 10.1016/j.chemosphere.2021.131822

In this study, fouling mechanism and modelling analysis of synthetic lignocellulose biomass and agricultural palm oil effluent was studied using polyethersulfone (PES) ultrafiltration (UF) 10 kDa membrane. The impact of process variables (transmembrane pressure (TMP), pH and concentration of feed solution) on lignocellulosic flux was analysed using pore blocking model. The feasible approaches on utilising deep learning artificial neural network (ANN) to predict smaller flux datasets are studied. Among the input variables, pH of lignin feed solution has significant control towards flux and lignin rejection coefficient for both lignin and lignocellulosic solution. Alteration in the structure of lignin at different pH conditions contributed in the improvement of lignin rejection coefficient to 0.98 at the feed pH of 9. A maximum steady state flux of 52.03 L/m2h was observed at the lower lignin concentration (0.25 g/L), TMP of 200 kPa and feed pH of 3. At high TMP and concentration, lignin rejection decreased due to enhancement of feed concentration on membrane surface. The mechanistic model exhibited that cake layer phenomena was dominant in both lignin and lignocellulosic solution. The proposed ANN model showed good correlation (R2-1.00) with experimental non-linear flux dynamic data of both lignin and synthetic lignocellulosic solution. In ANN analysis, activation function, algorithm and neuron effect have significant effect in design of accurate model for prediction of small flux datasets. Aerobically-treated palm oil mill filtration analysis also showed that cake layer phenomenon was dominant. A water recovery of 82 % was achieved even at low TMP under short durations.

Matched MeSH terms: Ultrafiltration*
Ultrafiltration membrane fabricated from polyethylene terephthalate plastic waste for treating microalgal wastewater and reusing for microalgal cultivation

Rawindran H, Arif Bin Hut N, Vrasna DK, Goh PS, Lim JW, Liew CS, et al.

Chemosphere, 2024 Jan;346:140591.
PMID: 37918531 DOI: 10.1016/j.chemosphere.2023.140591

Current study had made a significant progress in microalgal wastewater treatment through the implementation of an economically viable polyethylene terephthalate (PET) membrane derived from plastic bottle waste. The membrane exhibited an exceptional pure water flux of 156.5 ± 0.25 L/m2h and a wastewater flux of 15.37 ± 0.02 L/m2h. Moreover, the membrane demonstrated remarkable efficiency in selectively removing a wide range of residual parameters, achieving rejection rates up to 99%. The reutilization of treated wastewater to grow microalgae had resulted in a marginal decrease in microalgal density, from 10.01 ± 0.48 to 9.26 ± 0.66 g/g. However, this decline was overshadowed by a notable enhancement in lipid production with level rising from 181.35 ± 0.42 to 225.01 ± 0.11 mg/g. These findings signified the membrane's capacity to preserve nutrients availability within the wastewater; thus, positively influencing the lipid synthesis and accumulation within microalgal cells. Moreover, the membrane's comprehensive analysis of cross-sectional and surface topographies revealed the presence of macropores with a highly interconnected framework, significantly amplifying the available surface area for fluid flow. This exceptional structural attribute had substantially contributed to the membrane's efficacy by facilitating superior filtration and separation process. Additionally, the identified functional groups within the membrane aligned consistently with those commonly found in PET polymer, confirming the membrane's compatibility and efficacy in microalgal wastewater treatment.

Matched MeSH terms: Ultrafiltration