Poly Acrylic Acid Sodium Salt Research Articles

Effect of superabsorbent polymers on the properties of cement paste particle under different relative humidities

This study investigated the adsorption-desorption kinetics of polyacrylic acid sodium salt (AA) and polyacrylic acid-acrylamide copolymer (AM) under different relative humidities by the static water vapour adsorption experiment. TG and SEM-EDS were used to study the effect of Superabsorbent polymers (SAP) on the hydration degree of cement without mixing water. The results show that the adsorption capacity of AA is higher than that of AM, and the desorption capacity of AA is worse than that of AM. At 97%RH, AA and AM can absorb 233.2% and 210.5% of water vapour from the environment. Compared with cement without SAP, the addition of AA can increase the hydration degree of cement by 17.05%-53.58% (one-element system) and 14.21%-30.29% (binary system); the addition of AM can increase the hydration degree of cement by 8.82%-20.13% (one-element system) and 4.79%- 9.15% (binary system). The degree of cement hydration on the surface of SAP particles is higher than that of other parts. It was found that needle-like products exist on both the surface of SAP particles and cement particles and the calcium content is similar to the TG results. Calcium hydroxide and calcium element content are ranked as AA particle surface cement > AM particle surface cement > AA cement added > AM cement added > pure cement.

Effect of calcium-coacervate infiltration of artificial enamel caries lesions in de- and remineralizing conditions

ObjectivesCalcium-coacervate emulsions (CC) might be considered as mineral precursors to foster remineralization of carious dental hard tissues. This study analyzed the instant effect of repeated infiltration of artificial caries lesions with a CC emulsion as well as the effects of subsequent exposure of CC-infiltrated lesions to demineralizing and remineralizing environments. MethodsBovine enamel specimens were partly covered with varnish to leave three exposed windows. Artificial enamel caries lesions were created (pH 4.95, 17d). Baseline controls (BL) were obtained by preparing a thin section of each specimen. Specimens were allocated to five groups. In three groups lesions were etched with 37 % phosphoric acid gel, infiltrated with dipotassium hydrogen phosphate and subsequently with a calcium coacervate emulsion, prepared by mixing CaCl2 ⋅ 2H2O with polyacrylic acid sodium salt (PAA-Na). Subsequently, the infiltration effect was either analyzed immediately (Inf.) or after exposition to either de- (Inf.+DS) or remineralizing solution (Inf.+RS) for 10 or 20 days, respectively. In two control groups specimens were exposed to either DS or RS, respectively without prior CC infiltration. Integrated mineral loss [ΔZ(vol%×µm)] was analyzed using transverse microradiography (TMR). ResultsInfiltration of enamel caries lesions with coacervate solution resulted in only subtle immediate mineral gain even if repeated. When exposed to demineralizing conditions, infiltrated lesions showed significantly less mineral loss compared to untreated controls (p < 0.05; Kruskal Wallis) and exhibited characteristic mineral depositions within the lesion body. ConclusionsWhile immediate mineral gain by infiltration was only modest, the CC-emulsion might be able to prevent demineralization in acidic conditions. Clinical significanceCalcium coacervates might act protective against further demineralization when infiltrated into enamel caries lesions.

The nanostructure of polyelectrolyte complexes of QPDMAEMA-b-POEGMA copolymers and oppositely charged polyelectrolytes, and their stability in the presence of serum albumin.

Quaternized poly(2-(dimethylamino) ethyl methacrylate)-b-poly(oligo(ethyleneglycol) methyl ether methacrylate) (QPDMAEMA-b-POEGMA) is a copolymer of a positively charged block and a non-ionic hydrophilic block. The positively charged block, QPDMAEMA, electrostatically interacts with oppositely charged polymers, e.g., poly(acrylic acid) (PAA) and DNA, to form a complex. This complex is stable in aqueous solution due to the hydrophilic block, POEGMA, which provides colloidal stability and biocompatibility. Polyplexes can be used as non-viral vectors in gene therapy. Polyplexes are essential for delivering genetic materials into cells because they protect the genetic material from degradation before reaching the target cells, thus increasing the transfection efficiency. However, currently used polyplexes show a low transfection efficiency in vivo, probably because the polyplexes are exposed to blood proteins, such as serum albumin, which cause their dissociation. The main goal of this research is the morphology characterization of QPDMAEMA-b-POEGMA complexes with the sodium salt of polyacrylic acid (NaPAA), and with DNA by cryogenic transmission electron microscopy (cryo-TEM) and small-angle X-ray scattering (SAXS). These methods give qualitative and quantitative data about the morphology of the complexes. The morphology of the complexes was examined at different charge ratios (CRs). Complexes with NaPAA form core-corona spherical micelles and vesicular structures, whereas complexes with DNA form lamellar and hexagonal structures. The QPDMAEMA-b-POEGMA and DNA complexes were also examined after exposing them to bovine serum albumin (BSA). We found that BSA does not affect the complexes for seven days. This morphology characterization is essential for better design and formulation of vectors for gene therapy and polyelectrolyte complexes for biomedical applications.

Composite Nanoarchitectonics of Photoactivated Titania-Based Materials with Anticancer Properties.

The synthesis of titania-based composite materials with anticancer potential under visible-light irradiation is the aim of this study. In specific, titanium dioxide (TiO2) nanoparticles (NPs) chemically modified with silver were embedded in a stimuli-responsive microgel (a crosslinked interpenetrating network (IP) network that was synthesized by poly (N-Isopropylacrylamide) and linear chains of polyacrylic acid sodium salt, forming composite particles. The ultimate goal of this research, and for our future plans, is to develop a drug-delivery system that uses optical fibers that could efficiently photoactivate NPs, targeting cancer cells. The produced Ag-TiO2 NPs, the microgel and the composite materials were characterized through X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), micro-Raman spectroscopy, ultraviolet-visible spectroscopy (UV-Vis), dynamic light scattering (DLS) and transmission electron microscopy (TEM). Our results indicated that Ag-TiO2 NPs were successfully embedded within the thermoresponsive microgel. Either Ag-TiO2 NPs or the composite materials exhibited high photocatalytic degradation efficiency on the pollutant rhodamine B and significant anticancer potential under visible-light irradiation.

Improvement of millimeter-scale double droplets stability through synergistic noncovalent interactions

Driven by the need to prepare stable double droplets (the precursor of polymer shells for the laser-driven inertial confined fusion (ICF)) with surfactant concentration as little as possible, a synergistic noncovalent interaction route of the hydrophilic and hydrophobic interactions, hydrogen bonding and electrostatic repulsion to improve the oil-water interface performance has been proposed. Both the adsorption layer thickness and the adsorbed amount of the surfactants on the oil-water interface increase due to the formation of the hydrogen bonding between the poly(vinyl alcohol) (PVA) and polyelectrolytes (polystyrene sulfonate sodium (PSSS) or poly(acrylic acid) sodium salt (PAAS)), leading to the improvement of the interface viscoelasticity and the decrease of the interfacial tension compared with that of the polyelectrolytes alone. Therefore, owing to the synergistic noncovalent interactions, the stability of millimeter-scale double droplets is improved and monodisperse polymer shells have been successfully prepared from these stable double droplets by solvent evaporation method. This work provides more in-depth insights of the synergistic effects of the surfactants on the double droplets stability and gives some guidance on the optimization of the surfactants, benefiting the preparation of monodisperse polymer shells for ICF.

Multifunctional Composite Coatings Based on Photoactive Metal-Oxide Nanopowders (MgO/TiO2) in Hydrophobic Polymer Matrix for Stone Heritage Conservation.

Multifunctional composite coatings composed of metal oxide nanoparticles dispersed in polymer matrices are an advanced solution to solve the problem of stone heritage deterioration. Their innovative design is meant to be stable, durable, transparent, easy to apply and remove, non-toxic, hydrophobic, and permeable. Coating formulations for the protection of buildings and monuments have been intensively researched lately. Such formulations are based on multifunctional composite coatings incorporating metal oxides. The present work aims to combine the hydrophobic properties of sodium polyacrylate (NaPAC16) with the antimicrobial effectiveness, with promising antimicrobial results even in the absence of light, and good compatibility of MgO (a safe to use, low cost and environmentally friendly material) and TiO2 (with antibacterial and antifungal properties), in order to develop coatings for stone materials protection. MgO (pure phase periclase) and TiO2 (pure phase anatase) nanopowders were prepared through sol–gel method, specifically routes. Aqueous dispersions of hydrophobically modified polymer (NaPAC16, polyacrylic acid sodium salt) and MgO/TiO2 nanopowders were deposited through layer-by-layer dip coating technique on glass slides and through immersion on stone fragments closely resembling the mosaic stone from the fourth century AD Roman Mosaic Edifice, from Constanta, Romania. The oxide nanopowders were characterized by: Thermal analysis (TG/DTA), scanning electron microscopy (SEM), X-ray diffraction (XRD), BET specific surface area and porosity, and UV–Vis spectroscopy for band gap determination. An aqueous dispersion of modified polyacrylate polymer and oxide nanopowders was deposited on different substrates (glass slides, red bricks, gypsum mortars). Film hydrophobicity was verified by contact angle measurements. The colour parameters were evaluated. Photocatalytic and antimicrobial activity of the powders and composite coatings were tested.

Performance analysis of desiccant cooling system using polyacrylic acid sodium salt desiccant wheel

The adsorbent material has an important role in the improvement of desiccant cooling system performance. Super Desiccant Polymer (SDP) is chosen in this work as a sophisticated desiccant material characterized by excellent adsorption capacity and durability. The mathematical correlations of adsorption isotherm on SDP surface, adsorption heat and water diffusivity coefficient are used to model the SDP desiccant wheel by means of Comsol software. Modeling results are validated by an experimental data base. They serve as a base for the determination of the SDP wheel effectivenesses ԑ1 and ԑ1 which are equal to 0.02 and 0.83, respectively. The application of desiccant cooling system performance with SDP desiccant wheel in a hot and dry weather of the region of Gabes (south-eastern Tunisia) leads to a coefficient performance (COP) value equal to 1.1. This result is better than the COPs of other air conditioning desiccant systems which use zeolites and silica gel wheels. Moreover, the COP of desiccant cooling system with SDP desiccant wheel is the best for a wide range of operating conditions.

A New Comparative Evaluation for the Rheological and Filtration Properties of Water-Based Drilling Fluids Utilizing Sodium Salt of Linear and Cross-Linked Acrylate Polymer Hydrogels

Currently, polymers were applied as the most functional additives for optimizing the rheological behavior and filtrate volume control of water-based drilling fluids. To affirm this concept, the present work aims to prepare sodium salt of linear polyacrylic acid (NaLPAA), polyacrylamide (NaLPAM) and their cross-linked polymer hydrogels (NaCPAA and NaCPAM), in different ratios using N,N′-methylenebis(acrylamide), as a cross-linker, potassium persulfate and ascorbic acid as initiators. FTIR characteristic spectra, 1H NMR analysis, SEM micrographs and elemental analysis for the formed gels were employed to emphasize their consistence. TGA and TGA-DTG thermo-grams displayed that NaCPAA polymer hydrogel offered the highest thermal stability behavior. The swelling behavior of the prepared hydrogels was examined and demonstrated that CPAM showed the best behavior at pH = 4 (acidic medium). The rheological properties of the investigated water-based mud samples were studied at various temperatures. For sample containing 0.57% (2 g) of NaCPAA at ambient temperature, it showed the highest rheological behavior in which AV achieved the highest value at 118 cP, PV was recorded at 69 cP, and YP was detected at 99 lbf/100 ft2. At LTLP conditions, sample containing 0.57% of XC-polymer and 2.86% bentonite in its composition offered the most enhanced mud cake thickness at 4.2 mm. At HTHP conditions, the filtrate volume of sample containing 0.29% NaLPAA was detected at 35 mL and for sample containing 0.57% was calculated at 22 mL. In addition, the modified mud samples with the same recipe of NaLPAA and NaCPAA at different applied temperatures showed moderate rheological properties compared to the commercial XC-Polymer. Furthermore, NaCPAA manifested a reduction in the swelling properties of water-based mud system containing high amount of API bentonite (2.85%, 10 g) in which AV and PV were calculated at 30 and 17 cP, respectively. In addition, YP was recorded at 22 lbf/100ft2. So, it could be used as a thinner for water-based bentonite mud systems.

Xyloglucan-based hybrid nanocomposite with potential for biomedical applications

Natural polymer-based hybrid nanocomposites have been proposed as one of the most promising tools for biomedical applications, including disease treatment and diagnosis procedures. Xyloglucan nanocapsules can simultaneously load magnetic iron oxide nanoparticles and bioactive for a specific tissue, reducing the processes of degradation and metabolic inactivation of molecules with biological activity. In this work, magnetic nanocapsules of xyloglucan loaded with hydrophilic sulfated quercetin (MNXQ_SO3) were successfully synthesized by inverse miniemulsion process through interfacial polymerization. The polymeric shell formation of nanocapsules was evidenced by Fourier Transform Infrared spectroscopy and Transmission Electron Microscopy. The ferrofluid (Fe3O4@PAAS) incorporated into the xyloglucan nanocapsules was synthesized by hydrothermal method, using polyacrylic acid sodium salt as coating. Dynamic Light Scattering technique confirmed the nanomeric dimensions (202.3 nm) and the good colloidal stability (−40.2 mV) of MNXQ_SO3. The saturation magnetization analyses pointed out the superparamagnetic behavior of Fe3O4@PAAS (48 emu/g) and MNXQ_SO3 (4.2 emu/g). MNXQ_SO3 was able to modify the release profile of sulfated quercetin (67%) when compared to the free bioactive (100%), exhibiting a release profile compatible with the zero-order kinetic model. The results showed that the development of MNXQ_SO3 presents a new perspective for biomedical applications, including studies of targeted drug delivery.

Study on Water Absorption–Dehydration Characteristics for SAP Composite Soil for Rainwater Harvesting

As a water absorption material, superabsorbent polymer (SAP) has gained its popularity in agriculture and environmental remediations. This study conducted a comparative investigation on saturated water content of cinnamon soil mixed with SAP. Two SAPs, SAP1 and SAP2, with different behaviors were tested, where SAP1 is an organic superabsorbent polymer, and SAP2 is polyacrylic acid sodium salt polymer. The saturated water content of SAP composite cinnamon soil was investigated with the weighing method. The repeated water absorption capacity and dehydration behavior of SAP composite soil under different designed rainfall intensity were investigated with a soil column tester. The results showed that (1) cinnamon soil mixed with SAP increased the saturated soil water content, and SAP1 was more effective than SAP2; (2) SAP held strong water absorption ability and recycling efficiency with eight repeated absorption–dehydration tests; (3) the average dehydration time for SAP composite soil were 626 h and 1214 h under 5-year and 10-year design rainfall intensities.

Cobalt, copper and nickel-embedded chitosan/PAAS composite nanofiber mats as efficient heterogeneous catalysts for air oxidation of benzoin to benzil

We have applied electrospinning technique to embed cobalt, copper and nickel catalysts inside chitosan (CS) and polyacrylic acid sodium salt (PAAS) composite nanofiber mats (M@CS/PAAS) (M = Co2+, Cu2+ and Ni2+) as stable heterogeneous catalysts. Scanning electron microscopic analysis shows that the resultant M@CS/PAAS composite mats are bead-free and cylindrical nanofibers with mean diameter ranging from 474 to 504 nm, and the incorporated transition metal catalysts are homogeneously distributed inside the nanofibers in tight chelation with the chitosan amine groups. The M@CS/PAAS nanofiber mats exhibited excellent catalytic activity for atmospheric air oxidation of benzoin to benzil, and are much more stable than those prepared by conventional wetness impregnation (M-CS/PAAS nanofiber mats). Moreover, their catalytic activities and stabilities could be further enhanced by introduction of additional ligands through Schiff base transformation of the chitosan pendant amine groups. The free volume holes of the nanofibers were estimated to be considerably larger than the reactant and product molecules, allowing them to freely migrate around the internal catalytic sites. Taken together, we have demonstrated a straightforward approach to prepare efficient and recyclable heterogeneous catalysts derived from the first-row transition metal catalysts by entrapping them inside the chitosan/PAAS composite nanofibers.

Recyclable magnetic NiFe2O4/C yolk-shell nanospheres with excellent visible-light-Fenton degradation performance of tetracycline hydrochloride.

A photo-Fenton-like reaction was considered as an effective method for wastewater treatment because it could produce more oxidative species such as hydroxyl radicals (˙OH) to accelerate the reaction. In this paper, a NiFe2O4/C (abbr. as NFO/C) yolk-shell nanostructure was synthesized via one-step calcination using polyacrylic acid sodium salt (PAAS) NPs as a template. The nanocomposite was characterized using X-ray diffraction (XRD), field-emission scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and nitrogen adsorption-desorption, among others. The magnetically separable nanocomposite exhibited a high activity and recyclability towards the photodegradation of tetracycline hydrochloride (TC). In addition, the factors affecting the photodegradation process were systematically investigated, including the dosage of the NiFe2O4/C catalyst, the pH of the solution, and the volume of H2O2. Notably, the degradation rate of tetracycline hydrochloride (TC) reached 97.25% in 60 min in the presence of H2O2 under visible light irradiation (λ > 400 nm) with NiFe2O4/C. This work provides a simple and novel method to construct NiFe2O4/C yolk-shell nanostructures, which may be applied to the photodegradation of tetracycline hydrochloride from wastewater. Finally, a photocatalytic and stability mechanism is proposed, which may help us more comprehensively understand the photo-Fenton mechanism.

Improved electrochemical performance of LiCoPO4 using eco-friendly aqueous binders

The electrochemical performance of LiCoPO4 (LCP) as a high-voltage positive electrode for lithium-ion batteries is significantly improved by using the aqueous binder sodium carboxymethyl cellulose (CMC). The CMC not only provides a uniform electrode surface as shown by scanning electron microscopy and elemental mapping, but also suppresses the degradation of LiCoPO4 by scavenging HF in the electrolyte solution as demonstrated by FT-IR. In comparison with other water-soluble binders such as sodium alginate (ALG) and polyacrylic acid sodium salt (PAA), the homogeneous distribution of CMC within the electrodes accompanied by high accessibility of carboxylate groups in CMC are shown to be crucial factors to achieve enhanced performance with an excellent capacity retention of 94% after 20 cycles at a rate of C/10.

Zn(II) porphyrin-based photocatalytic synthesis of Cu nanoparticles for electrochemical reduction of CO2

Copper nanoparticles frequently exhibit unique electrocatalytic activity for the electrochemical reduction of carbon dioxide. However, the synthesis of Cu nanoparticles in aqueous systems remains rare. Herein, we report the synthesis of copper nanoparticles by using a zinc(II) porphyrin-based photocatalytic method in the presence of polyacrylic acid sodium salt (PAA) in water under visible light irradiation, leading to a series of Cu nanoparticles with relatively small average sizes ranging from 69 to 97 nm. PAA molecules adsorbed on Cu nanoparticles were simply removed by washing with copious amount of water. The purified Cu nanoparticles show some activity toward the electrochemical reduction of carbon dioxide as evidenced by linear sweep voltammetry (LSV) and gas chromatography (GC).

Zymography of Hybrid Layers Created Using Extrafibrillar Demineralization

A chelate-and-rinse extrafibrillar calcium chelation dentin bonding concept has recently been developed and investigated for its effectiveness in improving resin-dentin bonding by bridging the gap between wet and dry dentin bonding. The objective of the present study was to evaluate the gelatinolytic activity of hybrid layers (HLs) created using the chelate-and-rinse bonding technique. Gelatinolytic activity within the HL was examined using in situ zymography and confocal laser-scanning microscopy after 24-h storage or after thermomechanical cycling. Dentin specimens were bonded with Prime&Bond NT (Dentsply Sirona) after conditioning with 15 wt% phosphoric acid for 15 s (control) or 15 wt% polymeric chelators (sodium salt of polyacrylic acid; PAAN) of 2 different molecular weights for 60 s. For each reagent, bonding was performed using dry-bonding and wet-bonding techniques (n = 10). Slices containing the adhesive-dentin interface were covered with fluorescein-conjugated gelatin and examined with a confocal laser-scanning microscope. Fluorescence intensity emitted by the hydrolyzed fluorescein-conjugated gelatin was quantified. Gelatinolytic activity was expressed as the percentage of green fluorescence emitted within the HL. After storage for 24 h, enzymatic activity was only detected within the completely demineralized phosphoric acid–etched dentin, with values derived from dry bonding higher than those from wet bonding (P < 0.05). Almost no fluorescence signals were detected within the HL when dentin was conditioned with PAANs compared with the controls (P < 0.05). After thermomechanical cycling, enzymatic activities significantly increased for the phosphoric acid–conditioned, drying-bonding group compared with 24-h storage (P < 0.05). The present study showed that the use of the chelate-and-rinse bonding concept for both dry-bonding and wet-bonding approaches results in the near absence of matrix-bound collagenolytic activities in the HL even after aging. This may be attributed to fossilization of endogenous proteases via preservation of intrafibrillar minerals within the dentin collagen matrix.

Sustainable operation of osmotic microbial fuel cells through effective reproduction of polyelectrolyte draw solutes facilitated by cathodic pH increase

Osmotic microbial fuel cells (OsMFCs) take advantages of synergy between forward osmosis (FO) and microbial fuel cells (MFCs) for simultaneous wastewater treatment, bioenergy production, and water recovery. A unique feature for healthy operation of OsMFCs is an appropriate draw solute (DS) that can also act as a catholyte. Herein, polyelectrolytes (polyacrylic acid sodium salts, PAA-Na) was investigated as a DS/catholyte and reproduced with the aid of the high catholyte pH. Such a reproduction method is innovative, because it turns a drawback (high catholyte pH) into a useful resource, thereby reducing the demand for external input and leading to a clean production process. The results have showed that the OsMFC achieved a current density of 159 ± 6 A m−3, water flux of 12.7 ± 0.2 LMH, and low reverse salt flux of 0.05 ± 0.00 gMH with 32 wt% PAA-Na (2000 Da) as the DS. The DS recovery efficiency could be as high as 99.86 ± 0.04%, and the reproduced DS was successfully applied in the subsequent operation. With this reproduction method, the highest total operation cost was estimated at 0.104 $ m−3. Those results have demonstrated a new approach based on pH-dependent PAA DS reproduction towards further development of OsMFC technology for sustainable water/wastewater treatment and resource recovery.

Efficient recovery of polyelectrolyte draw solutes in forward osmosis towards sustainable water treatment

Forward osmosis (FO) technology has long been constrained by the slow development of appropriate draw solutes (DS) and the relatively high cost associated with DS recovery. In this study, a series of polyelectrolytes, polyacrylic acid sodium salts (PAA-Na) with different molecular weights, were explored as DS for FO applications with a focus on the recovery using combined pH and microfiltration (MF). The FO system achieved a high water flux of 18.02±0.51LMH, low reverse salt flux (RSF) of 0.110±0.004gMH, and the JS/JW of 6.1±0.3mgL−1 with 25wt% PAA-Na (2000Da) as the DS and DI water as the feed. The DS recovery efficiency by the combined pH+MF approach was 99.68% at pH of 4.35, and the operation cost was estimated at 0.037$m−3. Dynamic light scattering revealed that the hydrodynamic diameter of PAA increased with decreasing pH, resulting in PAA polymers precipitated as aggregates at the pH response point. The 25wt% 2000 PAA-Na achieved the water flux of 11.56±0.32LMH from synthetic seawater and 17.19±0.52LMH from the treated wastewater. These results have demonstrated efficient and cost-effective recovery of PAA DS for FO-based applications.

Head-group effect of surfactants of cationic type in interaction with propoxylated sodium salt of polyacrylic acid in aqueous solution

Polyacrylic acid (PAA) partially (50mol.%) neutralized by sodium hydroxide was propoxylated by propylene oxide (PO) obtaining terpolymer (PNPAA). The conductivity and tensiometry measurements were used to study an interaction of PNPAA with ionic-liquid surfactants of cationic type–nonylethylolammonium bromides in aqueous solutions of different concentrations at 25°C. From the results of these measurements, critical aggregation concentrations, critical micelle concentrations and the effective degree of counterion binding were determined. Depending on the nature of head-group of the cationic surfactant, the polyelectrolyte-surfactant interaction was studied and its impact on colloidal-chemical parameters of the polyelectrolyte/surfactant complexes was clarified. Petroleum-collecting properties of the obtained polyelectrolyte/surfactant complexes have been studied in various waters of a different mineralization degree.

Preparation, characterization and application of PS/SPEES–PES UF membranes for removal of ppm Cd2+ from aqueous media

Ultrafiltration membrane prepared from hydrophobic polymers like polysulfone or polyethersulfone (PES) suffers heavy membrane fouling during cross-flow filtration. Inclusion of hydrophilic polymer like SPEES in the membrane will increase the hydrophilicity of the membrane surface, this in turn would slow down the membrane fouling process and thus prolong the service life time of the polymeric membrane. This work involves the fabrication and characterization of nine KC-series ultrafiltration membranes containing various weight percent of sulfonated polymer (SPEES) via phase-inversion process; basic characteristics of these membranes like pure water flux, water content, surface charge density, molecular weight cut-off were determined. Application of KC-series UF membranes, containing various amounts of hydrophilic polymer [sulfonated polyetherethersulfone/polyethersulfone (SPEES/PES)], for the removal of Cd2+ in ppm concentrations from aqueous media via cross-flow filtration operation was investigated. Rejection of Cd2+ from the feed containing 50 ppm in Cd2+ and 100 ppm in polyacrylic acid sodium (225 kDa) salt achieved ~100%.

Application of poly (4-styrenesulfonic acid-co-maleic acid) sodium salt as novel draw solute in forward osmosis for dye-containing wastewater treatment

The selection of proper draw solution is crucial to guarantee a high-performance FO process with minimal reverse solute flux and easy draw solution recovery. In this study, a polyelectrolyte salt-poly (4-styrenesulfonic acid-co-maleic acid) sodium (P(SSA-co-MA)-Na), was applied as draw solutes in FO process. The effects of the chemical structure, osmotic pressure, viscosity of the draw solution and the resulted FO performance are investigated systematically. Because of the high osmotic pressure of the solution and the large molecular size, P(SSA-co-MA)-Na exhibits a higher water flux and a lower salt leakage as compared with polyacrylic acid sodium salts (PAA-Na) and poly (sodium-4-styrenesulfonate) (PSS-Na). Especially, a high water flux of about 15LMH and a significantly lower solute leakage of about 0.04gMH can be generated with 0.25g/ml P(SSA-co-MA)-Na draw solution and deionized water as the feed solution under PRO mode. The potential of P(SSA-co-MA)-Na draw solution is further evaluated for water recovery from the dye-containing wastewater via FO process. In addition, the diluted P(SSA-co-MA)-Na can also be regenerated by nanofiltration (NF) system. The overall performance proves that P(SSA-co-MA)-Na as draw solute in FO process is applicable.