Ultrafiltration Research Articles

Enhanced purification efficacy of the microflocculation–ultrafiltration process for raw water quality from multiple sources during heavy rainfall

ABSTRACT In this study, we utilized direct ultrafiltration (UF) and integrated microflocculation–ultrafiltration (MF–UF) processes to treat raw water from four distinct sources, covering both dry and heavy rainfall periods. We assessed the effectiveness of microflocculation (MF) as a pretreatment to enhance treatment efficiency under complex water conditions, focusing on its role in mitigating membrane fouling. The results demonstrated the superior adaptability of UF membranes when combined with MF pretreatment, particularly in managing high turbidity during heavy rainfall, a challenge for standalone UF processes in meeting regulatory standards. This integrated approach notably improved UV254 removal efficiency from approximately 60–80%. Additionally, excitation–emission matrix spectroscopy revealed that while the MF–UF process is effective in removing dissolved organic matter (DOM), it faces limitations with high DOM concentrations in raw water. Comparative analysis of membrane flux between the two methods showed that MF pretreatment reduces filtration time, enhances flux rates, and significantly decreases membrane fouling. Finally, scanning electron microscopy further provided insights into the structure and morphology of UF membrane surface filter cakes, illustrating how MF pretreatment contributes to the sustained efficiency of membrane flux.

Enrichment protocols for human conjunctival extracellular vesicles and their characterization.

The understanding of the role played by extracellular vesicles (EVs) in different tissues has improved significantly in the last years, but remains limited concerning the conjunctiva, a complex eye tissue whose role is pivotal for corneal protection. Here, we conducted a comparative study to isolate and characterize EVs from human conjunctival epithelial (IM-HConEpiC) and human conjunctival mesenchymal stromal cell (Conj-MSCs) secretomes using different isolation methods: differential ultracentrifugation (UC), and a combination of ultrafiltration (UF) with precipitation or size exclusion chromatography (SEC). EVs were characterized by total protein content, size, morphology, and expression of protein markers. EV functional effect was tested in an in vitro oxidative stress model. We successfully recovered EVs with the three methods, although significantly higher yields were obtained with UF-precipitation. Dynamic light scattering analysis confirmed the presence of nano-sized particles, being UC-isolated EVs larger than those isolated by UF-precipitation and UF-SEC. Atomic Force Microscopy showed EVs with a slightly ellipsoidal morphology. EVs enriched with UF-precipitation method were further analyzed, confirming the expression of Alix, CD63, TSG101, and Syntenin-1 by Western blotting and showing that Conj-MSC-derived EVs significantly reduced oxidative stress on IM-HConEpiC. Therefore, we conclude that UF-precipitation is the most efficient method for conjunctival EV enrichment.

Investigation of particle size distribution and ultrafiltration of digestates from short-fibre residues in paper mills

ABSTRACT Industrial digestates from short-fibre residues, generated in paper recycling mills, are driving interest in resource recovery. This study aims to explore their potential for water recovery. Understanding particle dynamics aids in optimizing dewatering for digestate management. The particle size distribution in this study revealed significant fractions: <0.63 μm (6–20%), 0.63–20 μm (38–52%), and >20 μm (11–16%). Pre-treatment with Na4P2O7 and H2O2 enhances settling and lowers total dissolved solids (TDSs) but results in variation of size distribution. Additionally, this study investigates further water reuse in paper mills, focusing on the quality of ultrafiltration (UF) permeate obtained from the digestate of short fibres. UF permeate analysis reveals deviations from freshwater standards in paper mills. Despite effective TS removal, UF permeate falls short of paper mill water standards due to high TDSs, electrical conductivity, and nutrient concentrations, necessitating further downstream treatment with nanofiltration or reverse osmosis. A substantial reduction of permeate flux from 31 to 5 L/(m2·h) over the time indicated fouling and inefficient membrane wash. The silt density index of the UF membrane at 30 min registered 2.1, suggesting potential fouling. Further investigations on optimizing UF operations to enhance permeate flux and exploring alternative UF membranes are required.

Comparative analysis of gut microbiota in incident and prevalent peritoneal dialysis patients with peritoneal fibrosis, correlations with peritoneal equilibration test data in the peritoneal fibrosis cohort.

The connection between peritoneal function and gut microbiota in peritoneal fibrosis (PF) patients remains uncertain. Peritoneal equilibration test (PET) was employed to evaluate peritoneal function in patients with peritoneal fibrosis (PF). 16S rRNA sequencing was used to analyze the gut flora in incident peritoneal dialysis (PD) and PF groups, identifying differential microbial communities. Spearman's correlation analysis, conducted using SPSS 26.0, was employed to explore the microbial associations with PF. In the PF group, the PET showed a 4-h dialysate-to-plasma creatinine ratio (D/PCr) ratio of 0.62 ± 1.01 and a 4-h ultrafiltration (UF) volume of 41.73 ± 76.71 mL with a 2.5% glucose dwell. The alpha diversity between the PD and PF groups did not exhibit a significant difference. The PD and PF groups were predominantly composed of Firmicutes, Tenericutes, and Ignavibacteriae. Linear discriminant analysis effect size (LEfse) analysis indicates that the Firmicutes, Lactobacillales, and Bacilli were significantly enriched in the PD group, whereas Lachnospiraceae, Phenylobacterium, and Caulobacteraceae were enriched among the PF group. The functional prediction of gut microbiota genes revealed variations in metabolic pathways related to lipid transport, energy metabolism, and post-translational protein modifications between the two cohorts. In the PF group, Ignavibacteriae and Bdellovibrio correlated positively with the 4-h D/PCr ratio (p <0.05), while Prevotella negatively correlated with the 4-h UF from 2.5% glucose dwell (p <0.05). The intestinal microbiota of patients newly initiated on peritoneal dialysis significantly differs from that of those with long-term peritoneal dialysis complicated by peritoneal fibrosis, with the latter's peritoneal function potentially linked to Prevotella, Ignavibacteriae, and Bdellovibrio.

Comparison of Hollow Fiber and Flat Sheet Membranes for Removing TDS and Turbidity of Palm Oil Mill Effluent Wastewater

The most significant pollutant produced from agricultural industry in Kalimantan, Indonesia is Palm Oil Mill Effluent (POME). Due to the high levels of suspended particles and organic matter, POME has become a brownish color with high turbidity, color, chemical oxygen demand, and oil and grease content. To recycle the POME wastewater as clean water, these pollutants must be eliminated. In this study, we compare the effectiveness of hollow fiber (HF) and flat sheet (FS) membrane to remove total dissolved solid (TDS) and turbidity from POME with varied filtration pressure. HF and FS membrane were prepared from PVDF and nylon66 polymer, respectively. The PVDF HF membrane was modified using TiO2 and SBE (spent bleaching earth) to improve HF membrane properties to maintaining fouling. Meanwhile, FS membrane was added by pectin to increase the hydrophilic properties. Overall membrane’s morphology was determined by Scanning Electron Microscopy (SEM) to investigate the membrane structure. Both of HF and FS membrane were operated via ultrafiltration (UF) under cross flow system. The filtration pressures were varied at 1-3 bar and followed by flux and rejection evaluation. The results show both HF and FS membranes has stability flux. In addition, TDS rejection up to 25% while turbidity is excellent high over 95% for all membranes. The fabrication HF membrane has finger like-sponge structure and FS membrane exhibits sponge asymmetric structure. Overall, all membranes perform highest water flux (FS membrane) while highest rejection conducted by HF membrane for POME wastewater treatment.

Microplastics removal from a hospital laundry wastewater combining ceramic membranes and a photocatalytic membrane reactor: Fouling mitigation, water reuse, and cost estimation

The release of microplastics (MPs) through industrial laundry wastewater accounts for 35 % of global MPs emissions into the environment and it is a significant environmental problem, especially because MPs can absorb contaminants of emerging concern (CECs) from garments. This study is the first to evaluate and perform a cost estimation of the MP removal from hospital laundry wastewater (HLWW) using a combination of ceramic membranes and a pilot-scale photocatalytic membrane reactor (PMR) as a fouling mitigation strategy. The HLWW, from a hospital in Copenhagen, Denmark, contained a total organic carbon (TOC) of 345 mg L⁻1 and 1.4 × 106 MP L−1, mainly of polyethylene terephthalate (PET) ranging between 100 and 200 μm in size. The pre-treatment with an ultrafiltration (UF) ZrO₂ membrane successfully removed 96 % of MPs and over 98 % of suspended solids and turbidity at an estimated cost of 0.45 US$ per m3 of permeate. In the PMR stage, ultraviolet light emitting diodes (UV LED) irradiation reduced irreversible fouling, improving permeate flow and minimizing the need for chemical cleaning. The Ce–Y–ZrO2/TiO2 photocatalytic membrane achieved over 99 % removal of turbidity, colour, and suspended solids, as well as 99.9 % removal of MPs, allowing the potential effluent reuse within the hospital laundry. Additionally, the retentate from the PMR process had lower TOC, easing the discharge of this concentrated stream. The cost estimation demonstrated that the photocatalytic degradation combined with traditional techniques, i.e. backflush and chemical cleaning, is more economical than using these techniques separately. Therefore, the total treatment cost was 1.09 US$ per m3 of permeate, which is lower than the cost of fresh water in Denmark. In conclusion, this innovative treatment strategy offers a sustainable and cost-effective solution for HLWW management, not only reducing water consumption by enabling water reuse in the hospital laundry but also advances towards achieving net-zero liquid discharge and contributing to the UN Sustainable Development Goals for clean water (Goal 6) and climate action (Goal 13).

Evaluation of clarification process of Indonesia’s sweet sorghum juice by ultrafiltration membrane and the physicochemical and sensorial properties of the sugar product

The juice derived from Sorghum bicolor L. exhibits a notable sugar content, rendering it a promising candidate for use as a sweetening agent. The presence of impurities in sorghum juice encompasses several substances such as non-sugar molecules, non-fermentable reducing agents, starch, and minerals like salt, magnesium, and calcium. The objective of this study was to investigate the impact of ultrafiltration (UF) membranes on the physicochemical properties of sorghum juice and sugar granules, as well as to identify customer preferences for these products. The study consisted of three primary phases. The first phase involved investigating the impact of 0–3 cycles of UF treatment on the physicochemical properties of the sorghum juice. The second stage involved comparing the characteristics of sugar granules obtained through UF and non-ultrafiltration (non-UF) methods. The third one focused on examining the preference of sorghum sugar granules in their natural state and as a sweetener for steeped black tea. A 5% significance level was employed in this work to conduct multivariate methodology of variance and the Friedman nonparametric test. The findings of the study indicate that the use of UF treatment has a simultaneous impact on the turbidity and color of sorghum juice. Non-UF sorghum sugar granules exhibit a superior aroma in comparison to UF granules while maintaining identical color, taste, and texture. Consumers exhibited a preference for steeped black tea sweetened with palm sugar, followed by rock sugar, granulated sugar, UF sorghum sugar granules, and non-UF.

Ultrasonographic Evaluation of Systemic Venous Congestion in Maintenance Hemodialysis Patients During Fluid Removal.

Fluid overload is a frequent and serious complication in hemodialysis patients. The combination of multiple point of care ultrasound (POCUS) measurements can identify significant venous congestion but its usefulness to determine ultrafiltration (UF) requirements and dry weight is unknown. Therefore, we evaluated prospectively patients in maintenance hemodialysis to establish the correlations between changes in venous congestion parameters and fluid removal. This was a prospective, single-center, observational study. POCUS venous congestion measurments were performed in 22 patients during 32 online post-dilutional hemodiafiltration sessions and findings were correlated with UF volume, central venous pressure and body water composition determined by multifrequency bioelectric impedance analysis (BIA). The pre dialysis weight was on average 1.9 kg above the BIA estimated dry weight, the average initial IVC diameter was <2 cm. An initial abnormal Hepatic Vein (HV) waveform was present in 26% (8) of the measurements. The average UF volume was 2084 ± 655 ml and correlated with changes in inferior vena cava (IVC) diameter (R= 0.34, CI 95% (0.18, 0.56) p < 0.05) but not with any other POCUS venous congestion parameters. Normalization of the IVC diameter and HV waveform was observed during the first UF hour in all initially altered measurements. Diameter reduction in the IVC correlated with total body water volume reduction estimated with BIA when measured immediately after fluid removal (R= 0.34, CI 95% (0.08, 0.56) p<0.05) Conclusion. Reduction in IVC diameter had a modest but significant correlation with UF volume in our patients on maintenance hemodiafiltration. POCUS may be used to monitor patients during UF.

Influence of Reclaimed Water on the Visual Quality of Automotive Coating.

In the present study, the possibility of recovering water in a car wash station was presented. The resistance of automotive coatings to washing water recovered at 50% and 70% from wastewater generated at car wash was tested. Wastewater treatment was carried out by ultrafiltration (UF) using tubular polyvinylidene fluoride (PVDF) membranes (100 and 200 kDa) manufactured by the PCI company. The membranes retained oil contamination, suspended solids, and over 60% of surfactants. For comparison, the 0.5% Turbo Active Green solution, used at professional car washes, was also applied in paint resistance studies. The tested solutions washed the painted surfaces of samples taken from car doors for 8 days. The resistance of automotive coatings to washing solutions was assessed by measuring gloss, Log Haze, RIQ, and Rspec parameters. Scratch resistance was also assessed. The results obtained in the current study indicated that the use of water recovered from wastewater did not deteriorate the quality of the car paint coating.

Enhanced removal of fluoride ions using lanthanum-doped coconut shell biochar in PVDF ultrafiltration membranes

Fluoride contamination in surface and ground water poses significant health risks, necessitating a low-energy, cost-effective removal method. Herein, an ultrafiltration (UF) adsorptive membrane doped with lanthanum (La)-based coconut shell biochar was synthesized to effectively remove fluoride ions. Based on the results of adsorption and membrane separation performance, it was found that La-based biochar showed a significantly higher adsorption capacity (126.7 mg F/g) compared to bare biochar (27.41 mg F/g), due to the oxygen-containing functional groups from La2O2CO3 that enhance binding sites and electrostatic attraction for fluoride ions. Furthermore, the addition of La-modified adsorbent to the polyvinylidene fluoride (PVDF) UF membrane markedly altered its structure and surface properties, changing the pore structure to porous, narrowing pore size, increasing active adsorption sites, and improving hydrophilicity. These changes boosted fluoride ion rejection from 9.53 % to 62.07 % with tiny effect on membrane permeability. More important, this UF adsorptive membrane exhibited excellent antifouling ability with the lowest flux decline (J/J0 =0.450) compared to pristine PVDF membrane (J/J0 =0.142), which was owing to the better improved surface properties. In all, this study provides a novel strategy for efficient, economic and selective separation of fluoride ions and further extends the application of UF to the field of ion removal.

Inhibition of dipeptidyl peptidase-IV by hydrolysates of beta-lactoglobulin isolated from Gir cow milk

The current study attempts to assess the dipeptidyl peptidase – IV (DPP-IV) inhibitory potential of β-lactoglobulin (β-Lg) isolated from milk of Gir cow. Whey was separated from skim milk by precipitation of casein followed by ultrafiltration (UF) to remove lactose and salts as permeate. β-Lg was separated from the UF retentate using salting out technique. Its purity was confirmed by SDS-PAGE and RP-HPLC. Hydrolysates of β-Lg were prepared using three different enzymes viz., pepsin, trypsin and Flavourzyme at different enzyme to substrate (E:S) ratios (1:25, 1:50, 1:100) and treated for 2-12 h durations. Pepsin-treated hydrolysate showed maximum DPP-IV inhibition of 77.62 ± 0.98 % (IC50 =3.78 mg/mL). Hydrolysate was passed serially through UF filters of 10 and 3 kDa. The permeate of 3 kDa, which exhibited 52.10 ± 0.72 % DPP-IV inhibition was fractionated through RP-HPLC and time based fractions were collected. All 41 fractions were again analysed for DPP-IV inhibition activity and 3 fractions which showed maximum DPP-IV inhibition activity were chosen for LC-MS/MS analysis. One novel peptide was identified through LC-MS/MS, which showed adequate DPP-IV inhibition (IC50 = 6.64 mmolL-1).

Improving separation efficiency of various micropollutants from water by polymer-enhanced ultrafiltration using oxidized alginate featuring less viscous and low filtration resistance

Polymer-enhanced ultrafiltration (PEUF) is an economical and energy-efficient alternative using a versatile water-soluble polymer (WSP) to remove micropollutants by electrostatic interactions, allowing size exclusion through ultrafiltration (UF) membranes due to the WSP being bigger than the pores of UF membranes. However, the WSP used in PEUF is so viscous that it inevitably causes significant filtration resistance and membrane fouling, reducing filtration and energy efficiency. To overcome this problem, in this study, sodium alginate (Alg), which significantly performs in removing cationic pollutants, was oxidized using sodium periodate to produce oxidized alginate (OxAlg). The retention and water flux profiles of OxAlg for three micropollutants, methylene blue (MB), ciprofloxacin, and tetramethylammonium hydroxide, using the PEUF method were investigated in terms of pH, ionic strength, polymer and pollutant amount. A comparison between Alg and OxAlg demonstrated 1.19% to 1.8% higher MB retention rates (99.31%-99.97%) and up to 4.07 times higher water flux depending on the amount of polymer added. Furthermore, OxAlg displayed excellent retention rates of the NF level and 20-60 times higher water flux than typical NF. This outstanding OxAlg performance was mainly due to OxAlg’s properties, such as the low viscosity, flexibility and the resulting accessibility, and appropriate size from the perspective of filtration. Lastly, OxAlg was found to have the potential to surpass the existing WSP in that it showed a higher maximum retention capacity than about 560 to 1250mg/g in the real-world pH enrichment test even before the saturation.

Environmental and economic assessment of urban wastewater reclamation from ultrafiltration membrane-based tertiary treatment: Effect of seasonal dynamic

This study aimed to assess the environmental and economic performance of an ultrafiltration (UF) tertiary treatment of effluent from an urban wastewater treatment facility. Data from a UF demonstration plant composed of commercially available equipment, including industrial hollow-fiber membranes was used to project a full-scale facility. The results from the demonstration plant recommended different ranges of transmembrane fluxes and sparging air demands under summer and winter conditions to prevent excessive fouling. The energy balance of the full-scale facility would be 0.308 ± 0.112 kWh·m−3 in summer and 0.140 ± 0.040 kWh·m−3 in winter, with blowers' being the main consumers (86–93 %). CAPEX accounted for €0.030 ± 0.002·m−3 in summer and €0.027 ± 0.002·m−3 in winter and membrane acquisition represented 66–69 % of the investment cost. Energy expenditure was the major OPEX cost (66–79 %), with a total operating cost of €0.077 ± 0.023·m−3 and €0.042 ± 0.008·m−3 in summer and winter, respectively. The final average value obtained for the TAC was €0.107 m−3 in summer and €0.068 m−3 in winter. The environmental assessment confirmed optimizing energy consumption and membrane requirements as the main factors influencing environmental sustainability. Specifically, summer and winter emissions of 0.079–0.175 and 0.043–0.079 kgCO2eq·m−3 (Global warming potential); 8.1 · 10−4–1.7 · 10−3 and 4.8 · 10−3–8.1 · 10−3 m3·m−3 (water consumption); 0.019–0.041 and 0.010–0.019 kg oileq·m−3 (fossil fuel scarcity); and 1.4 · 10−4–2.9 · 10−4 and 7.7 · 10−4–1.4 · 10−4 kg Cueq·m−3 (mineral resource scarcity) were calculated, respectively. The obtained permeate quality complied with the most stringent Spanish and EU regulations.

Effect of the Total Saponins of Bupleurum chinense DC. Water Extracts Following Ultrafiltration Pretreatment on Macroporous Resin Adsorption.

Macroporous resin is an efficient separation technology that plays a crucial role in the separation and purification of traditional Chinese medicine (TCM). However, the application of macroporous resins in TCM pharmaceuticals is hindered by serious fouling caused by the complex materials used in TCM. This study examines the impact of ultrafiltration (UF) membrane technology on the macroporous resin adsorption behavior of TCM extracts. In this paper, Bupleurum chinense DC. (B. chinense) water extracts were included as an example to study the effect of UF pretreatment on the macroporous resin adsorption of total saponins. The study results indicated that the adsorption of total saponins constituents from the water extracts of B. chinense on the macroporous resin followed the pseudo-second-order kinetic model and the Langmuir model. The thermodynamic parameters of adsorption, including enthalpy changes and Gibbs free energies, were negative, while entropy changes were positive. These results demonstrated that the total saponin components form a monolayer adsorption layer by spontaneous thermal adsorption on the macroporous resin, and that the adsorption rate is not determined by the rate of intraparticle diffusion. Following treatment with a UF membrane with an average molecular weight cut-off of 50 kDa, the protein, starch, pectin, tannin, and other impurities in the water extracts of B. chinense were reduced, while the total saponin content was retained at 82.32%. The adsorption kinetic model of the saponin constituents on the macroporous resin remained unchanged and was consistent with both the second-order kinetic model and the Langmuir model; the adsorption rate of the second-order kinetic model increased by 1.3 times and in the Langmuir model at 25 °C, the adsorption performance improved by 1.16 times compared to the original extracts. This study revealed that UF technology as a pretreatment method can reduce the fouling of macroporous resin by TCM extracts and improve the adsorption performance of macroporous resin.

Study on an Integrated Water Treatment System by Simultaneously Coupling Granular Activated Carbon (GAC) and Powdered Carbon with Ultrafiltration

The process of using powdered activated carbon (PAC) in conjunction with ultrafiltration (UF) has been widely adopted for the treatment of various types of water and wastewater. However, during the application of this integrated PAC-UF process, PAC tends to adhere significantly to the surface of the UF membrane, which exacerbates membrane fouling. To tackle this issue, this study proposed an innovative water treatment approach that simultaneously integrated granular activated carbon (GAC) and PAC/biochar with UF. In this setup, PAC/biochar was intended to enhance water quality, while the fluidized GAC particles were aimed at reducing membrane fouling and the deposition of PAC/biochar on the membrane surface. We systematically analyzed the operational performance of the integrated systems concerning fouling formation, PAC/biochar attachment, effluent quality, and foulant components. The results indicate that both PAC and biochar effectively improved effluent quality in terms of chemical oxygen demand (COD) and hardness, although they significantly deposited on the membrane surface during operation. Notably, PAC was more prone to attach to the membrane than biochar, and the fouling in biochar-UF systems was primarily attributed to the attachment of organic foulants rather than biochar itself. By combining with GAC, up to 46.01% of membrane fouling and 96.11% of PAC/biochar attachment were mitigated due to the strong mechanical action of the fluidized GAC particles. Importantly, the inclusion of fluidized GAC did not significantly affect effluent quality. Consequently, the GAC-PAC/biochar systems proposed in this study demonstrated dual benefits of improving effluent quality and ensuring stable operation, thereby providing a viable solution for efficient and sustainable water treatment.

Improved Antioxidant, Antihypertensive, and Antidiabetic Activities and Tailored Emulsion Stability and Foaming Properties of Mixture of Corn Gluten and Soy Protein Hydrolysates Via Enzymatic Processing and Fractionation

ABSTRACTBioactive peptides and protein hydrolysates have gained considerable attention in the food industry and functional food markets due to their diverse health effects, including antioxidant, antihypertensive, and antidiabetic properties. This study aimed to produce combined soy and corn protein hydrolysates using Alcalase (Al), modification of Al‐hydrolysates through sequential hydrolysis using Flavourzyme (Al‐FL), cross‐linking of Al‐hydrolysates using microbial transglutaminase (MTGase) (Al‐TG), and fractionation of Al‐hydrolysates by ultrafiltration (UF) with molecular weight (MW) cut‐off of 100 (Al‐F4), 30 (Al‐F3), 10 (Al‐F2), and 2 kDa (Al‐F1). Notably, the &lt; 2 kDa fraction (Al‐F1) showcased exceptional biological activities, including antioxidant (81.54% DPPH, 98.02% ABTS), antihypertensive (95.45%), and antidiabetic effects (44.72% α‐glucosidase, 77.52% α‐amylase), linked to its high hydrophobic amino acid content and low molecular weights (111 and 263 Da). Conversely, the higher molecular weight fraction (Al‐TG) excelled in emulsion and foam stability, attributed to its balanced amino acid profile and larger peptides (1385–7057 Da). Our findings reveal that specific protein hydrolysate fractions, particularly Al‐F1 and Al‐TG, are promising for applications in food and pharmaceutical formulations due to their enhanced biological and functional properties.

Unraveling the impact of salinity on biofouling on ultrafiltration membranes: A spectroscopic and microscopic view

Biofouling significantly hampers the performance and longevity of ultrafiltration (UF) membranes employed in saline wastewater treatment. This research addresses a crucial knowledge gap by meticulously investigating the influence of salinity variations (0–10 g/L NaCl) on biofouling characteristics, utilizing advanced spectroscopic and microscopic techniques. Combined blocking models elucidated the evolution of fouling mechanisms under varying salinity conditions. Higher salinity levels promoted cake layer formation, potentially circumventing initial fouling stages observed under lower salinity conditions. Quantification of confocal laser scanning microscopy images revealed a denser, thinner, and less heterogeneous cake layer at high salinity, composed of proteins, nucleic acids, and α-polysaccharides. The relatively high abundance of polysaccharides may contribute to maintaining osmotic pressure and bacterial cell viability. Moreover, the integration of the confocal Raman mapping technique and non-negative matrix factorization analysis was innovatively applied to characterize the biofouling layer, identifying the important role of carotenoids within the layer. Carotenoids were found to be more abundant in the upper regions of the biofouling layer formed at high salinity, potentially scavenging the reactive oxygen species within bacterial cells. In conclusion, this investigation offers a comprehensive understanding of the salinity-dependent alterations in the chemical composition and spatial structure of the membrane fouling layer. The findings may facilitate the development of targeted mitigation strategies to combat membrane biofouling in saline wastewater treatment applications.

Synthesis, characterization, and performance of MXene-modified PVC membranes for organic and inorganic separation

This study explores the transformation of polyvinyl chloride (PVC) flat sheet membranes for the first time using MXene, a hydrophilic two-dimensional (2D) nanosheet, to enhance ultrafiltration (UF) performance for wastewater treatment. The loading of MXene in the PVC solution was adjusted from 0 to 0.5 g in order to create modified membranes. The properties and performance of these membranes were thoroughly analyzed using field emission scanning electronmicroscopy (FESEM), contact angle (CA) measurements, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), water permeation flux, Bovine serum albumin (BSA) rejection, and Pb metal ions removal tests. Among the developed membranes, the N2-modified PVC membrane, with 0.4 g of MXene, exhibited the most favorable characteristics, including a contact angle of 65.77° and a porosity of .84.8 %. This membrane achieved the highest clean water permeation flux of 201.3 LMH, along with a 99.9 %, 91.03 % BSA and Pb metal ions rejection rate respectively, and a flux recovery ratio (FRR) of 90.2 %. The incorporation of MXene nanosheets significantly enhanced membrane efficiency compared to neat PVC membranes, demonstrating the promising capabilities of MXene-modified PVC membranes for effective wastewater treatment.

Membrane technology as a strategy for microplastics removal from landfill leachate: a review

ABSTRACT This study offers a comprehensive review of global microplastic (MP) contamination in landfill leachate (LL) and examines remediation strategies using membrane technologies such as ultrafiltration (UF), nanofiltration (NF), reverse osmosis (RO), and membrane bioreactors (MBRs). Research investigations and full-scale applications of these technologies for treating LL demonstrate their efficacy as viable solutions for on-site leachate treatment, providing promise in mitigating LL toxicity and reducing the environmental and human health risks associated with MP pollution. While the size of MPs in LL may raise questions about the necessity of using NF and RO membranes for MP removal, these processes are commonly employed in many landfills to serve as barriers for MP retention. Despite the high efficacy of MBR systems in removing MPs, the accumulation of MPs in the biological sludge can adversely affect biological performance and membrane fouling, necessitating further exploration. In general, membrane technologies face challenges such as membrane fouling and the release of MPs. Therefore, further research is needed to address MP removal, understand membrane–MP interactions, explore cleaning strategies in LL treatment and their impact on MP release from membranes, and study the integrity of membranes after continuous exposure to LL under varied operating conditions.

Sustainable Acid Mine Drainage Water Reclamation Using Silica-pectin Multichannel Tubular Membrane: A Comparison of Ultrafiltration Vs Pervaporation

The practice of coal mining has been demonstrated to exert a detrimental impact on the surrounding environment, particularly through the formation of acid mine drainage (AMD) ponds, which have the potential to pollute water sources. The reclamation of AMD is necessary to treat wastewater to ensure its safety for discharge into the environment and subsequent use as clean water. This study aims to treat AMD by comparing ultrafiltration (UF) and pervaporation (PV) processes utilizing silica-pectin multichannel membranes. The membranes were fabricated by coating silica-pectin sol on an inner surface of multichannel tubular support. The UF process was conducted under various pressures (1-3 bar), while the PV process was tested at various feed temperatures. Both permeate were collected and analyzed using several parameters (pH, Mn, and conductivity). The results showed that the UF process is more effective in collecting permeate flux over 136.6 L.h-1.m-2 at 3 bar pressure. Meanwhile, PV performs high permeate quality with Mn and conductivity rejection of 99.9 and 96.5%, respectively. Both UF and PV processes exhibit slightly increasing permeate pH with a range of 4.5-5.6. It concluded that multichannel silica-pectin membranes successfully reclamation AMD to enhance water quality. In addition, the UF process is more affordable for recycling AMD with high permeate flux, pretty good Mn, and conductivity rejection of over 95%.