Cellulose Triacetate Membrane Research Articles

Radiation-induced grafting of polyethyleneimine onto cellulose triacetate membrane for separation of cesium ions from aqueous solution

Radiation grafting of polyethyleneimine (PEI) onto the surface of cellulose triacetate (CTA) membrane was successfully performed. Pre-radiation and co-radiation were applied by gamma rays at the dose of 12 kGy. FT-IR, SEM, XPS, contact angle, zeta-potential, grafting ratio, etc. Were used to characterize the PEI-CTA membranes before and after grafting. The FT-IR spectrum showed that a notable discernible shoulder peak of N–H appeared for amide at co-radiation and pre-radiation, and XPS analysis indicated that co-radiation achieved the highest N percent of 9.75%, suggesting that PEI was introduced into the membrane surface. In a forward osmosis (FO) process, the PEI-CTA membrane obtained higher cesium, Cs(I), retention (95–97%) than the CTA membrane with Cs(I) retention of 92%. Cs(I) fluxes significantly decreased from 0.09 to 0.02–0.03 mmol m−2h−1 after PEI modification. Effective Cs(I) retention was attributed to increase of the positive charges on CTA membrane when PEI was added, which exerted a repulsive effect on Cs(I), preventing them from moving towards the membrane direction. In the FO process, the PEI-CTA membrane featured the water flux of 23 L m−2 h−1 a little lower than that of CTA membrane (24 L m−2 h−1). Although modified PEI increased the hydrophilicity, the increase of water flux did not occur with the co-irradiated membrane, which was related to the high graft, higher thickness and resistance of the membrane.

Perfluorooctanoic acid-contaminated wastewater treatment by forward osmosis: Performance analysis

Perfluorooctanoic acid (PFOA) is a persistent compound, raising considerable global apprehension due to its resistance to breakdown and detrimental impacts on human health and aquatic environments. Pressure-driven membrane technologies treating PFAS-contaminated water are expensive and prone to fouling. This study presented a parametric investigation of the effectiveness of cellulose triacetate membrane in the forward osmosis (FO) membrane for removing PFOA from an aqueous solution. The study examined the influence of membrane orientation modes, feed pH, draw solution composition and concentration, and PFOA concentration on the performance of FO. The experimental results demonstrated that PFOA rejection was 99 % with MgCl2 and slightly >98 % with NaCl draw solutions due to the mechanism of PFOA binding to the membrane surface through Mg2+ ions. This finding highlights the crucial role of the draw solution's composition in PFOA treatment. Laboratory results revealed that membrane rejection of PFOA was 99 % at neutral and acidic pH levels but decreased to 95 % in an alkaline solution at pH 9. The decrease in membrane rejection is attributed to the dissociation of the membrane's functional groups, consequently causing pore swelling. The results were confirmed by calculating the average pore radius of the CTA membrane, which increased from 27.94 nm at pH 5 to 30.70 nm at pH 9. Also, variations in the PFOA concentration from 5 to 100 mg/L did not significantly impact the membrane rejection, indicating the process's capability to handle a wide range of PFOA concentrations. When seawater was the draw solution, the FO membrane rejected 99 % of PFOA concentrations ranging from 5 mg/L to 100 mg/L. The CTA FO treating PFOA-contaminated wastewater from soil remediation achieved a 90 % recovery rate and water flux recovery of 96.5 % after cleaning with DI water at 40 °C, followed by osmotic backwash. The results suggest the potential of using abundant and cost-effective natural solutions in the FO process, all without evident membrane fouling.

Metal-phenolic network as precursor complex coating for forward osmosis membrane with enhanced antifouling property.

In this study, a multi-functional layer was developed based on the commercially available cellulose triacetate (CTA) forward osmosis (FO) membrane to improve its antifouling property. Tannic acid/ferric ion (TA/Fe3+) complexes were firstly coated as a precursor layer on the membrane surface via self-assembly. Afterwards, the tannic acid/diethylenetriamine (TA/DETA) hydrophilic functional layer was further coated, following Ag/polyvinylpyrrolidone (PVP) anti-bacterial layer was formed in situ through the reducibility of TA to obtain TA/Fe3+-TA/DETA-Ag/PVP-modified membrane. The optimized precursor layer was acquired by adjusting the buffer solution pH to 8, TA/Fe3+ ratio to 4 and the number of self-assembled layers to 5. The permeability testing results illustrated that the functional layer had an insignificant effect on the membrane transport parameters. The TA/Fe3+-TA/DETA-Ag/PVP-modified membrane simultaneously exhibited excellent physical and chemical stability. The coated membrane also demonstrated enhanced anti-bacterial properties, achieving 98.63 and 97.30% inhibition against Staphylococcus aureus and Escherichia coli, respectively. Furthermore, the dynamic fouling experiment showed a 12% higher water flux decrease for the TA/Fe3+-TA/DETA-Ag/PVP CTA membrane compared to the nascent CTA membrane, which proved its excellent antifouling performance. This work provides a feasible strategy to heighten the antifouling property of the CTA FO membrane.

Improving antifouling performance of FO membrane by surface immobilization of silver nanoparticles based on a tannic acid: diethylenetriamine precursor layer for municipal wastewater treatment.

In this study, a facile method for multifunctional surface modification on forward osmosis (FO) membrane was constructed by surface immobilization of AgNPs based on tannic acid (TA)/diethylenetriamine (DETA) precursor layer. The cellulose triacetate (CTA) FO membranes modified by TA and DETA with different co-deposition time (6 h, 12 h, 24 h) were investigated. Results indicated that the TA/DETA (24)-Ag CTA membrane with a TA/DETA co-deposition time of 24 h was identified to be optimal, which attained more hydrophilic. And it had the bacterial mortality of Escherichia coli and Staphylococcus aureus reaching 98.23% and 99.83% respectively and possessed excellent physical and chemical binding stability. Meanwhile, the coating layer resulted in the antifouling ability without damaging the membrane intrinsic transport characteristics. As for synthetic municipal wastewater treatment, the water flux of CTA FO membrane decreased approximately 49% of the initial flux after running for 14 days. In contrast, the flux decline rate of TA/DETA (24)-Ag CTA membrane was about 37%. Furthermore, less foulant deposition and higher recovery rate of water flux was observed for TA/DETA (24)-Ag CTA membrane, implying that the modified membrane effectively alleviated membrane fouling and processed a lower flux decline during municipal wastewater treatment. It was attributed to the enhanced surface hydrophilicity and antibacterial property of the coating layer, which improved antifouling property.

Chiral separation of D,L‐phenylglycine by cellulose triacetate membranes

AbstractEnantiopure pharmaceuticals are especially important in medicinal applications. Phenylglycine, as a critical pharmaceutical intermediate, is often utilized in single enantiomeric form for drug synthesis. Chiral membrane separation offers advantages such as simple operation, low energy consumption, and scalability, holding great potential for chiral drug separations. In this work, cellulose triacetate (CTA) membranes are prepared via phase inversion and used for permeation experiments driven by a concentration gradient to investigate selective permeation of D,L‐phenylglycine solutions. Scanning electron microscopy reveals surface and cross‐sectional morphologies of the fabricated membranes. After single‐factor optimization, the CTA membrane exhibits an enantiomeric excess of 68.94% for D,L‐phenylglycine separation. The membrane maintains its selective permeation capability after repeated use. This indicates the CTA membrane has favorable chiral selective permeation for D,L‐phenylglycine solutions with stable performance. The chiral carbon on the six‐membered ring of the CTA backbone, as well as the single‐handed helical structure of the backbone, are thought to be responsible for the chiral selectivity of the membrane. This is the first report of using CTA membranes for chiral amino acid separation, providing experimental references and theoretical basis for membrane separation of racemic mixtures. It could facilitate scalable applications of chiral membranes.

Synthesis and characterization of an innovative sodium alginate/polyvinyl alcohol bioartificial hydrogel for forward-osmosis desalination.

Recently, hydrogels have been widely applied as draw agents in forward osmosis (FO) desalination. This work aims to synthesize bioartificial hydrogel from a blend of sodium alginate (SA) and polyvinyl alcohol (PVA) using epichlorohydrin (ECH) as a crosslinker. Then this prepared hydrogel was applied as a draw agent with cellulose triacetate membrane in a batch (FO) cell. The effects of the PVA content in the polymer blend and the crosslinker dose on the hydrogel's swelling capacity were investigated to optimize the hydrogel's composition. Furthermore, the water flux and the reverse solute flux of the optimum SA/PVA hydrogel were evaluated in a batch (FO) unit under the effect of the hydrogel's particle size, feed solution (FS) temperature, FS concentration, and membrane orientation. Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), X-ray diffraction (XRD) and compression strength tests were used to characterize the prepared hydrogel. Results revealed that the equilibrium swelling ratio (%) of 5228 was achieved with a hydrogel that had 25% PVA and a crosslinking ratio of 0.8. FO experiments revealed that the maximum water flux of 0.845 LMH achieved, when distilled water was used as FS, average hydrogel's particle size was 60µm, and the FS temperature was 40°C.

A Sensor (Optode) Based on Cellulose Triacetate Membrane for Fe(III) Detection in Water Samples

Iron is a heavy metal that often contaminates water. High iron concentrations are toxic to human health, so monitoring its presence in water is necessary. Iron in water can be detected using an optical sensor (optode). This research aims to fabricate an optode based on a cellulose triacetate membrane with a selective reagent against Fe(III). The optode was fabricated by mixing cellulose triacetate polymer, a plasticiser (a mixture of oleic acid and acetophenone), aliquot-336, and thiocyanate as a selective reagent. Membrane performance was tested based on working range, linearity, limit of detection and quantitation, precision, and accuracy. The performance of the membrane showed a linear response in the concentration range of 0.1–4 mg/L with a coefficient of determination (R2) of 0.9937, limit of detection of 0.0250 mg/L, limit of quantitation of 0.0757 mg/L, repeatability precision with a relative standard deviation of 3.31%, and an accuracy of 100.49%. Optode selectivity was good for interfering ions Cr(VI) and Pb(II). The colour complex of the optode was stable until the 10th day. The application of iron detection in water samples shows an average concentration of 0.2541 mg/L with good precision and accuracy.

Performance and stability of cellulose triacetate membranes in humid high H2S natural gas feed streams

The current study aims to provide a thorough understanding of the separation performance of the cellulose triacetate (CTA) membrane material in humid high H2S natural gas feed streams. A systematic study of the gas separation performances of CTA polymers has been carried out in self-standing symmetric films and asymmetric hollow fiber membranes. The separation performance in H2S-containing mixtures (CH4/CO2/H2S, 80/5/15 mol%) were evaluated at 30 and 50 °C at 20, 35 and 50 bar, including higher hydrocarbons (butane and toluene) in the presence of various levels of humidity, up to 4500 ppm or 80 % RH, depending on conditions of temperature and pressure. For the first time, the effect of these contaminants and humidity together under sour gas conditions has demonstrated the promising stability of CTA membrane separation performance, both in terms of H2S permeability and H2S/CH4 selectivity. The improvement in H2S permeability is due to a combination of H2S plasticization and competitive sorption making this phenomenon even more attractive and worth studying further.

Support-free assembled molecular layer by layer - HPAN forward osmosis membranes

The internal concentration polymerization (ICP) phenomenon may hinder the flux of forward osmosis (FO) membranes. The mitigation of ICP can be achieved by employing a porous support layer structure. Nevertheless, conventional interfacial polymerization (IP) methods encounter challenges in establishing a dense selective layer upon a highly porous support layer. In this study, the support-free assembled molecular layer-by-layer (SF-mLbL) was suggested to manufacture the thin-film composite (TFC) membrane by combining the separately fabricated polyamide (PA) selective layer with a tunable thickness and the highly porous support layer. The SF-mLbL (8 wt%) membrane had a higher water flux and selectivity (43.52 ± 0.89 LMH/0.15 ± 0.01 g L−1) than those (10.34 ± 0.48 LMH/0.75 ± 0.02 g L−1 and 7.41 ± 0.18 LMH/0.81 ± 0.01 g L−1) of IP-PA and commercial cellulose triacetate membranes as 0.5 M NaCl draw solution in FO mode. Consequently, the SF-mLbL membranes exhibited significant improvement in the FO process with well-balanced permselectivity.

Macrocyclic derivatives of imidazole as chromoionophores for bismuth(III)/lead(II) pair

18-membered diazomacrocycles with imidazole or 4-methylimidazole residue as a part of macrocycle were used as chromoionophores in bismuth(III) and lead(II) dual selective optodes for the first time. Cellulose triacetate membranes doped with macrocyclic chromoionophores are bismuth(III) and lead(II) selective with color change from orange/red to different shades of blue and violet, respectively. Results obtained for model and real samples of bismuth(III) and lead(II) showed that easily accessible and regenerable sensor materials can be used for spectrophotometric and colorimetric detection and determination of bismuth(III) and lead(II). The obtained LOD values for bismuth(III) are 1.63 × 10−7 M and 3.03 × 10−7 M with spectrophotometric and colorimetric detection, respectively, when using optode with imidazole residue. For sensing material with 4-methylimidazole in macroring the lowest detection limits were obtained for lead(II): 2.14 × 10−7 M and 3.99 × 10−7 M with spectrophotometric and digital color analysis detection mode, respectively.

Forward osmosis TFN membrane prepared by adjusting a PDA/GO-Fe3+-TA interlayer on porous CTA substrates

Cellulose triacetate (CTA) is commonly used as the material for forward osmosis (FO) membranes due to its good chlorine resistance, fouling resistance and wide availability. In this work, the implications of various solvents on the appearance and desalination capacity of CTA FO membranes were systematically investigated. CTA membranes with large pore size and high porosity were constructed by using spray-modified non-solvent induced phase separation (s-NIPS). The water flux of CTA membranes fabricated by s-NIPS using DMSO as the solvent was up to 34.4 L m−2h−1, which was 5.6 times higher than HTI commercial membranes, and the reverse salt flux was only 10.9 g m−2h−1. A poly-dopamine (PDA) /graphene oxide (GO) -Fe3+-tannic acid (TA) interlayer was introduced to adjust the cross-linking degree of the polyamide (PA). And thin-film nanocomposite (TFN) membranes (PA-PDA/GO-Fe3+-TA-CTA) were fabricated successfully. The water flux was 35.8 L m−2h−1 and the reverse salt flux decreased to 5.84 g m−2h−1. These experimental results propose an emerging approach to design and develop high performance FO membranes in a rational way.

Hybrid osmotically assisted reverse osmosis and reverse osmosis (OARO-RO) process for minimal liquid discharge of high strength nitrogenous wastewater and enrichment of ammoniacal nitrogen

Ammoniacal nitrogen (NH4N) is a ubiquitous nitrogen pollutant found in wastewater, which could cause eutrophication and severe environmental stress. It is therefore necessary to manage NH4N by enrichment and recovery for potential reuse, as well as to regulate the amount of environmental discharge. Hybridization of membrane-based processes is an attractive option for further enhancing water and nutrient reclamation from waste streams; thus, in this present work, a hybrid osmotically assisted reverse osmosis (OARO) and reverse osmosis (RO) process was demonstrated for subsequent ammoniacal nitrogen enrichment and wastewater discharge management. Using a commercially-available cellulose triacetate membrane module, model and real wastewater containing approximately 4,000ppm NH4N were effectively dewatered and enriched to a final NH4N content of 40,300ppm. This corresponds to enrichment of around 10 times and approximately 90% pure water recovery. The effective combination of both processes resulted in high efficiency, as well as economical and energy-saving benefits, as shown by the process performance and our preliminary techno-economic analysis. The specific energy consumption of the hybrid process projected to operate at a capacity of 2,000 m3h−1 was determined to be 8.8kWh m−3, or 0.56kWh kg−1 NH4Cl removed/recovered for an initial feed solution containing around 15,300ppm NH4Cl. Hybrid OARO and RO operation was able to achieve satisfactory enrichment by the OARO process and obtaining clean water by the RO process. The hybrid OARO-RO process has shown great potential as a suitable end-stage membrane-based process for wastewater dewatering and NH4N enrichment and recovery toward a circular economy and environmental management, as well as clean water recovery.

Theoretical Model for the Prediction of Water Flux during the Concentration of an Olive Mill Wastewater Model Solution by Means of Forward Osmosis.

Currently, understanding the dynamics of the interaction between the agents in a process is one of the most important factors regarding its operation and design. Membrane processes for industrial wastewater management are not strangers to this topic. One such example is the concentration of compounds with high added value, such as the phenolic compounds present in olive mill wastewater (OMW). This process is a viable option, thanks to the forward osmosis (FO) process, osmotically driven by a saline stream. In this context, the transport of the solute and the solvent through the FO membranes, although essential to the process, remains problematic. This paper presents a study to predict, by means of a theoretical model, the water flux for two membranes (a cellulose triacetate flat sheet and a polyamide hollow fiber with integrated aquaporin proteins) with different characteristics using a sodium chloride solution as the draw solution (DS). The novelty of this model is the consideration of the contribution of organic compounds (in addition to the inorganic salts) to the osmotic pressure in the feed side. Moreover, the geometry of the modules and the characteristics of the membranes were also considered. The model was developed with the ability to run under different conditions, with or without tyrosol (the compound chosen as representative of OMW phenolic compounds) in the feed solution (FS), and was fitted and evaluated using experimental data. The results presented a variability in the model prediction, which was a function of both the membrane used and the FS and DS, with a greater influence of tyrosol observed on the permeate flux in the flat cellulose triacetate membrane.

Fabrication and kinetic evaluation of dye adsorption capability of metal Oxide@RGO nanocomposites integrated cellulose triacetate membranes

Reduced Graphene Oxide (RGO) and its derivatives exhibit remarkable removal abilities of water pollutants that can further be enhanced by the incorporation of the metallic nanoparticles. However, the challenging collection of GO sheets and fabrication method of RGO-based materials during the adsorption process, constraint their practical uses. The integration of the RGO-based materials on the polymeric matrix offers a solution to this problem. In current study, three types of metal oxide@RGO nanocomposites integrated Cellulose Triacetate (CTA) membranes with adsorption abilities were prepared by a facile blending and phase inversion technique. The fabricated membranes exhibited selective adsorption for azo dyes at room temperature. The adsorption parameters depicted the Langmuir and pseudo-first order kinetic order reaction. It was found that the adsorption process was directed by the inter-particle diffusion. These membranes were found to be effective against varying range of the pollutants and can be fabricated by the facile techniques.

Forward Osmosis Process for the Treatment of Wastewater from Textile Industries

This paper was aimed to study the efficiency of forward osmosis (FO) process as a new application for the treatment of wastewater from textile effluent and the factors affecting the performance of forward osmosis process.The draw solutions used were magnesium chloride (MgCl2), and aluminum sulphate (Al2 ( SO4)3 .18 H2O), and the feed solutions used were reactive red, and disperse blue dyes.Experimental work were includes operating the forward osmosis process using thin film composite (TFC) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), feed solutions concentration (5 – 30 mg/l), draw solutions flow rate (10 – 50 l/hr), feed solutions flow rate (20-60 l/hr), constant pressure and temperature were maintained at 0.5 bar and 30ºC respectively. And includes operating the forward osmosis process using cellulose triacetate (CTA) membrane as flat sheet for different draw solutions and feed solutions. The operating parameters studied were : draw solutions concentration (10 – 90 g/l), and feed solutions concentration (5 – 30 mg/l), constant temperature at 30ºC. It was found that water flux increases with increasing draw solution concentration, and feed solution flow rate and decreases with increasing draw solution flow rate and feed solution concentration for TFC and CTA. It was found MgCl2 given water flux larger than Alum. And also found that reactive red given water flux larger than disperse blue.The experiments also show that CTA membrane gives higher water flux than TFC membrane for forward osmosis operation. The increase in water flux for CTA is about 12.85% than TFC.

Kinetics of Glucoregulatory Peptide Hormones during Hemodialysis with Cellulose Triacetate and Polysulfone Dialyzers in Patients with Diabetes and End-Stage Kidney Disease.

The mechanisms behind reported decreases in plasma insulin and glucagon during hemodialysis (HD) are not clear. Here, we investigated these mechanisms during HD treatment and the characteristics of insulin and glucagon removal when using two super high-flux membranes. In an experimental study, clearance, adsorption rates, and reduction rates of insulin and glucagon were investigated when using cellulose triacetate (CTA) and polysulfone (PS) membranes in a closed circuit using bovine blood. In a clinical study, 20 diabetes patients with end-stage kidney disease who were stable on HD were randomly selected for two HD sessions with two different membranes. At 1 h after the initiation of HD, insulin and glucagon clearance were measured, and the reduction rates were also investigated. In the experimental study, the PS membrane showed significantly higher clearance, adsorption rates, and reduction rates of insulin and glucagon compared with the CTA membrane. Although glucagon was detected in the ultrafiltration fluids in both membranes, insulin was absent in the PS membrane. In the clinical study, both membranes showed significant reductions in plasma insulin and glucagon at each time point. The PS membrane showed significantly higher insulin clearance and reduction rates compared with the CTA membrane. The two membranes showed no significant difference in glucagon clearance, but the glucagon reduction rate was significantly higher with the PS membrane. Our findings show that HD with the two super high-flux membranes used removes significant amounts of glucoregulatory peptide hormones from plasma in patients with diabetes and end-stage kidney disease, potentially affecting their glucose metabolism.

Forward-Reverse Osmosis Processes for Oily Wastewater Treatment

In this study, the feasibility of Forward–Reverse osmosis processes was investigated for treating the oily wastewater. The first stage was applied forward osmosis process to recover pure water from oily wastewater. Sodium chloride (NaCl) and magnesium chloride (MgCl2) salts were used as draw solutions and the membrane that was used in forward osmosis (FO) process was cellulose triacetate (CTA) membrane. The operating parameters studied were: draw solution concentrations (0.25 – 0.75 M), oil concentration in feed solution (FS) (100-1000 ppm), the temperature of FS and draw solution (DS) (30 - 45 °C), pH of FS (4-10) and the flow rate of both DS and FS (20 - 60 l/h). It was found that the water flux and oil concentration in FS increase by increasing the concentration of draw solutions, the flow rate of FS and the temperature for a limit (40oC), then, the water flux and oil concentration decrease with increasing the temperature because of happening the internal concentration polarization phenomenon. By increasing the oil concentration in FS and the flow rate of the DS, the water flux and oil concentration in FS decreased, while it had a fluctuated behavior with increasing pHof oily wastewater. It was found also that MgCl2 gives water flux higher than NaCl. So the values of resistance to solute diffusion within the membrane porous support layer were 55.93 h/m and 26.21 h/m for NaCl and MgCl2 respectively. The second stage was applied reverse osmosis process using polyamide (thin film composite (TFC)) membrane for separating the fresh water from a diluted (NaCl) solution using different parameters such as draw solution concentration (0.08–0.16 M), feed flow rate (20–40 l/h).

#3798 A MULTICENTER CLINICAL STUDY OF CELLULOSE TRIACETATE MEMBRANES AND POLYSULFONE MEMBRANE DIALYZERS IN MAINTENANCE HEMODIALYSIS PATIENTS

Abstract Background and Aims With the continuous improvement of dialysis membrane materials, polysulfone (PS) has replaced traditional cellulose membranes with excellent biocompatibility and dominates the market applications. In our clinical work, we found that the allergic reaction disappeared after the application of cellulose triacetate (CTA) in patients who were allergic to PS. In this study, we compared the differences in biocompatibility and solute clearance of CTA and PS dialyzers during long-term dialysis treatment. Method In this study, a multicenter clinical study was conducted, and patients attending Fuxin Mining Bureau Hospital, Northeast International Hospital and Shenyang Medical College Affiliated Central Hospital receiving maintenance hemodialysis from April 2019 to April 2020 were selected as the study population. The patients were divided into a polysulfone membrane group (n = 10) and a cellulose triacetate membrane group (n = 13) based on whether they tolerated the polysulfone membrane dialyzer, and all patients in the CTA group had an allergic reaction to the polysulfone membrane dialyzer. The effects of the two membranes on White Blood Cell (WBC), platelet (PLT), Hemoglobin(Hb), Complement3(C3), Complement4(C4), Tumor Necrosis Factor-α (TNF-α), Interleukin-1 (IL-1), interleukin-6 (IL-6), hypersensitive C-reactive protein (hs CRP), IgE, serum phosphorus (P), creatinine (CR), blood urea nitrogen (BUN), parathyroid hormone (PTH) were compared before and after the single dialysis session and after 12 months of dialysis,and Urea removal rate (URR) and spKt /V were calculated. Results There were no statistically significant differences between the two groups in the comparison of basic information such as age, gender, dialysis age and primary disease. Before the application of CTA and PS dialyzer treatment, there was no statistically significant comparison between groups for all observed indicators. After application of CTA and PS single dialysis: (i) The difference between the 2 groups of β2-MG (Z = -2.039, P = 0.041) and TNF-α (Z = -2.491, 0.013) was statistically different. (ii) There were no statistically significant differences between two groups in the comparison of hematological system, such as WBC, PLT, HB; complement, such as C3, C4; inflammatory factors, such as: IL-1, IL-6, hs CRP, IgE; uremic toxins, such as: P, CR, BUN, PTH (P>0.05). After the 12th month of regular hemodialysis treatment with PS and CTA: (i) The differences between the 2 groups for P (Z = -2.096, P = 0.036), BUN (Z = -2.038, P = 0.042), and spKt/V (t = -2.147, P = 0.049) were statistically significant. (ii) The difference between the 2 groups after 12 months of dialysis P (t = 0.114, P = 0.041) and before dialysis was statistically different between groups, and the other indexes mentioned above were not statistically different. Conclusion After a single dialysis session, TNF-αin the PS group was elevated and the biocompatibility of CTA was better than PS. The CTA group had better clearance of β2-MG than PS, and spKt/V reached the standard. After long-term dialysis, the effect of CTA on inflammation and complement system was not different compared with PS, and there was no difference in biocompatibility between the two membranes. spKt/V in the CTA group reached the standard, and the clearance of BUN and P was better than that of PS.

Design and Preparation a New Composite Hydrophilic/Hydrophobic Membrane for Desalination by Pervaporation.

Herein, experimental and theoretical approaches were used to design a new composite membrane for desalination by pervaporation. The theoretical approaches demonstrate the possibility to reach high mass transfer coefficients quite close to those obtained with conventional porous membranes if two conditions are verified: (i) a dense layer with a low thickness and (ii) a support with a high-water permeability. For this purpose, several membranes with a cellulose triacetate (CTA) polymer were prepared and compared with a hydrophobic membrane prepared in a previous study. The composite membranes were tested for several feed conditions, i.e., pure water, brine and saline water containing a surfactant. The results show that, whatever the tested feed, no wetting occurred during several hours of desalination tests. In addition, a steady flux was obtained together with a very high salt rejection (close to 100%) for the CTA membranes. Lastly, the CTA composite membrane was tested with real seawater without any pretreatment. It was shown that the salt rejection was still very high (close to 99.5%) and that no wetting could be detected for several hours. This investigation opens a new direction to prepare specific and sustainable membranes for desalination by pervaporation.

No predialysis treatment of blood primes in pediatric continuous kidney replacement therapy

BackgroundPediatric continuous kidney replacement therapy (CKRT) uses blood as the priming fluid in the CKRT circuit to prevent hemodilution and hypotension and is dialyzed using a dialysate before the start of CKRT. This study aimed to investigate the safety of CKRT using a protocol of no predialysis after blood priming in underweight infants, based on hemodynamic and laboratory data changes.MethodsThis single-center retrospective cohort study included children weighing < 5 kg after cardiac surgery treated with CKRT from March 2019 to February 2022. Our protocol is as follows. We used 6-Fr vascular access, 20 mL priming volume of 0.3 m2 cellulose triacetate membrane, 37 mL priming volume of the pediatric extracorporeal circuit, and 57 mL of total extracorporeal volume. Heparin saline was prefilled with the extracorporeal circuit, and then, 30 mL of packed red blood cells was used to prime. Subsequently, the therapy was started without predialysis treatment of blood primes and vasopressin was used as a vasopressor for hypotension. Hemodynamic and laboratory data changes were studied.ResultsCKRT was performed in 8 patients, and 19 circuit connections were analyzed. Hypotension was observed in 10/19 (52.6%) connections, but all patients recovered within approximately 10 min. Ionized calcium, bicarbonate, and pH values were significantly decreased (p = 0.001, < 0.001, and < 0.001, respectively) before dialysis. However, 60 min after dialysis, pH recovered to predialysis levels and ionized calcium and bicarbonate recovered to > 95% of the levels before extracorporeal circulation. Moreover, potassium levels, which were not significantly different between extracorporeal circulation and dialysis initiation (p = 1.000), were significantly decreased after dialysis (p = 0.046). Lactate and hematocrit did not significantly change either before dialysis (p = 0.131 and 0.071, respectively) or after dialysis compared to the time of extracorporeal circulation (p = 1.000 and 0.591, respectively).ConclusionsCKRT, using our protocol, could be safely performed without predialysis treatment of blood primes in children weighing < 5 kg.