Increase In Additive Concentration Research Articles

Tensile properties of blends of ultra-high molecular weight polyethylene with very low molecular weight polyethylenes

Tensile properties of blends of ultra-high molecular weight polyethylene with very low molecular weight polyethylenes

Fabrication and Characterization of Novel Mixed Matrix Polyethersulfone Nanofiltration Membrane Modified by Iron-Nickel Oxide Nanoparticles

In this study, a mixed matrix polyethersulfone/iron-nickel oxide nanoparticle nanofiltration membrane was prepared by the solution casting technique. Polyvinylpyrrolidone was also used as a membrane pore former in membrane fabrication. The effect of iron-nickel oxide nanoparticles concentration in the casting solution on the membrane structure and performance was investigated. Scanning optical microscopy (SOM) and scanning electron microscopy analysis (SEM), water contact angle, NaCl/Na2SO4 salt rejection, water flux and tensile strength measurements were also carried out in membrane characterization. SOM images showed relatively uniform particle distribution and surface for the prepared membranes. Moreover, SEM images showed that the macro-voids’ size was enhanced in the membrane sub-layer with an increase of additive concentration. Results showed that increasing iron-nickel oxide nanoparticles from 0 to 0.1 wt.% in the membrane matrix caused a decrease in contact angle from 63 to 43° and again increased to 56° by increasing the particles concentration to 1 wt.%. The membrane water flux was enhanced sharply with an increase of nanoparticle concentration up to 0.01 wt.% in the membrane matrix and then decreased slightly at higher additive contents. Salt rejection was generally improved with an increase of nanoparticle concentration. Membrane mechanical strength was initially declined by using iron-nickel oxide nanoparticles up to 0.1 wt.% in the membrane matrix and then increased at higher additive contents. The nanocomposite membranes showed more appropriate antifouling capacity compared to a pristine PES membrane. The effect of feed concentration on membrane salt rejection and water flux was also studied.

Mixed matrix heterogeneous cation exchange membrane filled with clay nanoparticles: membranes’ fabrication and characterization in desalination process

In this research mixed matrix PVC based-co-clay nanoparticles heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of clay nanoparticles concentration in the casting solution on membrane electrochemical properties was studied. Scanning optical microscopy (SOM) images showed uniform particles distribution and relatively uniform surfaces for the prepared membranes. The membrane water content was improved initially by an increase of additive content ratio up to 1%wt in casting solution and then it began to decrease by more additive concentration. Moreover, swelling was measured less than 5% in thickness and negligible in length and width for the prepared membranes. Membrane potential, transport number and permselectivity were improved by increase of nanoparticles loading ratio. Utilizing Cloisite nanoparticles up to 1%wt in the casting solution also led to an increase in permeability and flux for prepared membranes. The ionic permeability and flux were decreased again by a further increase in additive concentration from 1 to 4%wt. Also, membranes exhibited lower permeability and flux for bivalent ions in comparison with monovalent type. The membrane E-conductivity and mechanical strength was enhanced by an increase of nanoparticles concentration in membrane matrix. The modified membrane containing 1%wt clay nanoparticles showed more suitable electrochemical properties compared to others.

Fabrication of mixed matrix heterogeneous cation exchange membrane modified by titanium dioxide nanoparticles: Mono/bivalent ionic transport property in desalination

Polyvinylchloride-co-TiO2 nanoparticle mixed matrix heterogeneous cation exchange membranes were prepared by the solution casting technique. The effect of TiO2 nanoparticle concentration in casting solution on membrane physico-chemical properties was studied. SOM images showed uniform particle distribution and relatively uniform surfaces for prepared membranes. Membrane water content was decreased by an increase of additive concentration. Ion exchange capacity was improved initially by an increase of nanoparticle content and then decreased. Transport number and selectivity initially showed a nearly constant trend by an increase of additive content up to 2wt.% and then decreased sharply by a more additive concentration. Sodium permeability was enhanced by an increase of nanoparticle concentration up to 0.5wt.% and then decreased by a more additive content from 0.5 to 2wt.%. Sodium permeability was increased another time by a more increase in additive concentration from 2 to 16wt.% and then showed a decreasing trend by a more nanoparticle content. A different trend was found for barium permeability. FTIR spectra analysis decisively proved stronger affinity of TiO2 nanoparticles for barium ions compared to sodium ones. A decrease of pH enhances positive charge distribution on nanoparticle surface and improves the flux. Membrane mechanical strength was also improved by an increase of nanoparticle content ratio in the membrane matrix.

Novel nanocomposite heterogeneous cation exchange membrane prepared by MWCNTs-co-silver nanolayer composite nanoparticles: Physico/chemical characterization and investigation of concentration effect

Nanocomposite polyvinyl chloride/multi walled carbon nano tubes (MWCNTs)-co-silver (Ag) nanolayer composite nanoparticles heterogeneous ion exchange membranes were prepared by solution casting techniques. MWCNTs-co-Ag nanolayer composite nanoparticles were prepared by magnetron sputtering method. The effect of used composite nanoparticles and electrolyte’s concentration on physico/chemical properties of membranes was studied. Scanning and transmission electron microscopy and X-ray diffraction results showed uniform distribution and crystalline structure for the composite nanoparticles. Images also showed relatively uniform distribution for the membranes. Membrane transport number, selectivity and electrical conductivity were improved by increase of additive content in membrane matrix. All mentioned parameters were also enhanced by increase of electrolyte concentration. Membranes exhibited lower selectivity/transport number for bivalent ions compared to monovalent type. Membrane average roughness was decreased slightly by increase of additive content. Membrane ionic flux was decreased initially by increase of additive content up to 0.5%wt and then began to increase by more additive concentration. Mechanical stability of membranes was also improved by using of composite nanoparticles in membrane matrix. Modified membrane containing 4%wt composite nanoparticles showed better electrochemical properties compared to others.

The inhibitory role of autolysed yeast of Saccharomyces cerevisiae, vitamins B3 and B6 on acrylamide formation in potato chips

The efficiency of vitamins B3, B6, and the autolysed yeast on the decrease of acrylamide formation in potato chips was investigated in this paper and the optimal levels of three additives were summarized. Ten experimental groups including a control group were organized for all additives. Potatoes were soaked in different concentrations (0.1, 0.5, and 1%) of vitamin B3, B6, and the autolysed yeast treatments. The acrylamide level in potato chips was determined by gas chromatography–mass spectrometry (GC/MS). Results indicated 58, 50, and 33% reduction in acrylamide formation, when the vitamins B3, B6, and the autolysed yeast of Saccharomyces cerevisiae addition levels were 1 g/100 g. The elevated inhibitory effect was achieved with an increase in additive concentration. The present study indicated that vitamins B3, B6, and the autolysed yeast could significantly reduce the acrylamide content, without affecting the original flavor and crispness of potato chips.

Electrochemical characterization of mixed matrix nanocomposite ion exchange membrane modified by ZnO nanoparticles at different electrolyte conditions “pH/concentration”

In this research, novel PVC based nanocomposite ion exchange membrane was prepared by casting technique. ZnO nanoparticles were employed as semiconductor additive in membrane fabrication. The effect of nanoparticles concentration on properties of home-made membranes was studied. A relatively uniform surface for the membranes and uniform particles distribution were observed in SOM images. The membranes were characterized in different electrolyte conditions “concentrations/pH”. Results revealed that membrane water content, membrane potential, transport number and selectivity were enhanced initially by increase of additive concentration up to 10wt% in membrane matrix and then showed decreasing trend by more additive loading. The ionic permeability and flux were also decreased initially by increase in additive content up to 5wt%. The permeability and flux were increased another time by more increase in additive content. An opposite trend was observed for membrane electrical resistance. Moreover, membranes showed higher transport number and selectivity at pH 7 compared to other pH values. Membrane electrical conductivity was decreased by increase of pH value. Also membrane transport number and selectivity were initially enhanced by increase of electrolyte concentration and then began to decrease slightly at high electrolyte concentration.

Preparation and electrochemical characterization of mixed matrix heterogeneous cation exchange membranes filled with zeolite nanoparticles: Ionic transport property in desalination

In the current research mixed matrix PVC based-co-zeolite nanoparticles heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of used additives and also electrolyte's concentration and pH variations on membrane electrochemical properties was studied. Results showed that membrane water content, membrane potential, transport number and selectivity were improved initially by use of zeolite nanoparticles up to 8%wt. in the casting solution and then began to decrease by more increase in additive concentration from 8 to 16%wt. Utilizing zeolite nanoparticles in the casting solution also led to increase in membrane electrical conductivity and ionic flux obviously. Membrane transport number, selectivity and membrane electrical conductivity were all enhanced by increase of electrolyte concentration. Moreover, membranes showed higher transport number/selectivity and lower electrical resistance at pH7 compared to other pH values. Among the prepared membranes, modified membrane containing 8%wt. zeolite nanoparticles showed more suitable electrochemical properties compared to others. Also obtained results revealed that modified membranes in this study are comparable with that of other commercial ones. The obtained results are valuable for electro-membrane processes especially electrodialysis for water recovery and treatment.

Fabrication of novel mixed matrix electrodialysis heterogeneous ion-exchange membranes modified by ilmenite (FeTiO3): electrochemical and ionic transport characteristics

Novel mixed matrix polyvinylchloride-based electrodialysis heterogeneous cation-exchange membranes were prepared by casting technique. Ilmenite (FeTiO3) was employed as additive in membrane fabrication. The effect of additive concentration on electrochemical properties of membranes was studied. Water content was decreased slightly by increase of FeTiO3 concentration. Ion-exchange capacity was improved initially by increase in additive content to 16 wt.% and then showed decreasing trend by more additive loading. Membrane potential, transport number and selectivity were enhanced initially in NaCl solution by increase of FeTiO3 content up to 16 wt.% and then decreased by more additive loading. Increment of FeTiO3 concentration led to decrease of selectivity and transport number in BaCl2 solution. Permeability and flux were declined slightly by increase in additive content up to 8 wt.% and then began to increase sharply by more additive content from 8 to 16 wt.%. Permeability and flux were decreased again by more additive concentration from 16 to 32 wt.%. Electrodialysis experiment results in laboratory scale showed higher dialytic rate for modified membrane compared to pristine one. Membrane areal electrical resistance was declined by increase of additive concentration. Membranes exhibited higher selectivity and flux for monovalent ions compared to bivalent ones.

Fabrication of novel heterogeneous cation exchange membrane by use of synthesized carbon nanotubes-co-copper nanolayer composite nanoparticles: Characterization, performance in desalination

In this research polyvinyl chloride/multi walled carbon nanotube–co-copper nanolayer composite nanoparticles heterogeneous cation exchange membranes were prepared by solution casting techniques. The MWCNT–co-Cu nanolayer composite nanoparticles were prepared by magnetron sputtering method. The effect of composite nanoparticle concentration on physico-chemical properties of membranes was studied. The SEM, TEM and XRD results showed uniform distribution and crystalline structure for the deposited Cu nanolayer on the MWCNTs' surface. SOM images also showed relatively uniform particle distribution for the membranes. The membrane potential, transport number, selectivity and electrical conductivity were improved by an increase of additive content in prepared membranes. Membrane average roughness was decreased slightly by an increase of additive concentration. Membrane ionic permeability and flux were decreased initially by an increase of additive ratio up to 0.5wt.% and then showed an increasing trend by more additive concentration. Furthermore, mechanical stability of prepared membranes was improved by an increase of MWCNT–co-Cu nanolayer composite nanoparticle content in membrane matrix. Also, modified membrane containing 4wt.% composite nanoparticles showed better electrochemical properties compared to other modified membranes, membrane containing pure MWCNTs and unmodified ones.

Preparation and characterization of nanocomposite heterogeneous cation exchange membranes modified by silver nanoparticles

We prepared polyvinylchloride based nanocomposite heterogeneous cation exchange membranes by solution casting technique using cation exchange resin powder as functional groups agent and tetrahydrofuran as solvent. Silver nanoparticles were also used as fillers in membrane fabrication. The effect of silver nanoparticles concentration in casting solution on membrane physico/chemical and antibacterial characteristics was studied. The SEM images showed compact structure for the modified membranes. X-ray diffraction results also revealed that membrane crystallinity was clearly changed by increase of nanoparticle concentration. Membrane selectivity and transport number were enhanced initially by increase in nanoparticle content up to 4%wt in prepared membrane, and then showed decreasing trend by more increase in additive concentration from 4 to 8%wt. Selectivity and transport number were enhanced another time by further increase in nanoparticle loading ratio from 8 to 16%wt. Opposite trend was found for the membranes’ average grain size by variation in additive content. Ionic flux was also clearly enhanced by using Ag nanoparticles in membrane matrix. Moreover, modified membranes showed good ability in decrease of Escherichia coli growth rate.

Electrodialysis heterogeneous anion exchange membrane modified by PANI/MWCNT composite nanoparticles: Preparation, characterization and ionic transport property in desalination

In this research polyaniline (PANI)-co-multi walled carbon nanotubes (MWCNTs)/polyvinylchloride (PVC) nano-composite heterogeneous anion exchange membranes were prepared by solution casting technique. The effect of PANI/MWCNT nanoparticle concentration on membrane electrochemical properties was studied. Membrane water content was decreased by the increase of nanoparticle concentration. Ion exchange capacity (IEC) was improved initially by the increase of nanoparticle concentration up to 2wt.% and then showed decreasing trend by more additive content from 2 to 4wt.%. IEC was enhanced again with more increase in additive concentration from 4 to 16wt.%. Fixed ionic concentration (FIC) also showed increasing trend by an increase in nanoparticle content. Membrane potential, transport number and selectivity were improved in NaCl and Na2SO4 ionic solutions by the increase of PANI/MWCNT nanoparticles. Also membranes exhibited lower selectivity and transport number for bivalent ions compared to monovalent type. Membrane permeability and flux were enhanced initially in both monovalent and bivalent ionic solutions by an increase in additive concentration up to 1wt.% and then showed decreasing trends by more additive content from 1 to 16wt.%. Prepared membranes showed lower permeability and flux for bivalent ions compared to monovalent type. Modified membranes showed better performance in comparison with pristine membrane.

Electrochemical characterization of mixed matrix heterogeneous cation exchange membrane modified by aluminum oxide nanoparticles: Mono/bivalent ionic transportation

Polyvinylchloride/aluminum oxide nanoparticles mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of Al2O3 nanoparticles concentration on membrane electrochemical properties was studied. It was found that membrane water content was enhanced by increase of additive concentration in prepared membrane. Increase of aluminum oxide nanoparticles loading ratio in casting solution also caused to decrease in ion exchange capacity. Obtained results revealed that membrane permselectivity and transport number were improved initially in sodium chloride and barium chloride ionic solutions by increase of aluminum oxide nanoparticles concentration up to 2wt% in prepared membranes and then showed decreasing trend by more increase in additive content. Also membranes exhibited lower selectivity and transport number for bivalent ions in comparison with monovalent ones. Furthermore, membrane ionic permeability and flux were decreased initially by increase in aluminum oxide nanoparticles loading ratio up to 2wt% and then increased again by more additives concentration. Opposite trend was found for membrane areal electrical resistance. Results showed that modified membranes in this study are comparable with that of other commercial ones.

Fabrication and electrochemical characterization of PVC based electrodialysis heterogeneous ion exchange membranes filled with Fe3O4 nanoparticles

In this research, novel polyvinylchloride based electrodialysis heterogeneous cation exchange membranes were prepared by casting technique. Iron oxide nanoparticle was also employed as additive in membrane fabrication. The effect of additive concentration on electrochemical properties of homemade membranes was studied. SOM images showed uniform particles distribution and relatively uniform surfaces for the membranes. Membrane water content and ion exchange capacity were increased initially by increase in additive loading ratio to 2%wt and then showed decreasing trend by higher additive content to 8%wt. Membrane potential, permselectivity and transport number all were enhanced with increase of additive content in sodium and barium chloride ionic solutions. They showed different behaviors for the membranes in lead nitrate ionic solution. Membranes exhibited lower potential, selectivity and transport number for bivalent ions compared to monovalent ones. Permeability and flux were enhanced initially in sodium and barium chloride ionic solutions by increase in additive content up to 2%wt and then began to decrease by more additive loading. The electrodialysis experiment results showed that dialytic rate of lead ions removal was increased obviously by increase of additive concentration. Modified membranes showed better electrochemical properties compared to pristine one.

Electrochemical, morphological and antibacterial characterization of PVC based cation exchange membrane modified by zinc oxide nanoparticles

In the current research, mixed matrix polyvinylchloride based heterogeneous cation exchange membranes were prepared by solution casting technique. Zinc oxide nanoparticle was also utilized as additive in membrane fabrication. The effect of ZnO nanoparticles concentration in casting solution on physico-chemical and antibacterial characteristics of membranes was studied. SEM images showed compressed structure for the modified membranes. Images also exhibited relatively uniform surfaces for the membranes. 3D SEM images showed smooth surface for membranes at high ZnO loading ratio content. X-ray diffraction results revealed that membrane crystalinity was improved by increase of nanoparticles’ concentration. The membrane selectivity and transport number were increased initially by increase of additive content up to 8 %wt in casting solution and then showed decreasing trend by more ZnO concentration to 16 %wt. The membrane ionic flux also enhanced initially by increase of zinc oxide nanoparticles content up to 4 %wt and then began to decrease. The modified membrane containing 4 %wt zinc oxide nanoparticles showed superior characteristics compared to other modified membranes and pristine/unmodified ones. The modified membranes also showed good ability in E.coli removal.

Fabrication of mixed matrix heterogeneous ion exchange membrane by multiwalled carbon nanotubes: Electrochemical characterization and transport properties of mono and bivalent cations

In this research, polyvinylchloride/multiwalled carbon nanotubes (MWCNTs) mixed matrix heterogeneous cation exchange membranes were prepared by solution casting technique. The effect of MWCNT concentration on membrane electrochemical characteristics was studied. Membrane water content was increased initially by increase of additive concentration up to 4wt.% and then showed decreasing trend by more additive content. Increase of MWCNTs' loading ratio in casting solution also caused to decrease in ion exchange capacity. Membrane permselectivity and transport number were declined initially for monovalent ionic solution by increase of additive loading up to 4wt.% and then increased by more additive concentration. Results revealed that membrane selectivity and transport number were improved slightly in bivalent ionic solution by increase of MWCNT concentration up to 8wt.% and then decreased sharply by more additive concentration. The monovalent ionic flux was enhanced by increase of additive content. Also ionic flux was improved initially for bivalent ions by increase of additive concentration up to 2wt.% and then decreased by more additive concentration from 2 to 8wt.%. The bivalent ionic flux showed increasing trend with further increase in additive concentration. Membrane areal electrical resistance was decreased by increase of additive concentration.

Reduction of foodborne pathogens during cattle manure composting with addition of calcium cyanamide

Abstract Inactivation of four species of foodborne pathogens (E. coli, Salmonella, E. faecalis, and S. aureus) was investigated during laboratory-scale composting of fresh cow manure with addition of calcium cyanamide (CaCN2) at constant temperature conditions, and the effects of temperature and additive content of CaCN2 on the efficacy of inactivation were evaluated. At different composting temperatures (20, 30, 37 and 50 °C), a significant inhibition or quick inactivation of pathogens were observed during 10 d composting with addition of 2.0% CaCN2, and the effect was more obvious at mesophilic temperatures compared to thermophilic temperature. Therefore, the ideal additive content of CaCN2 was determined at 30 °C through mixing 2.0%, 2.5%, and 3.0% CaCN2 with manure. With increase in additive content of CaCN2, the efficacies of pathogen inactivation also increased. However, the result indicates that, no less than 2.5% CaCN2 should be mixed with the manure to entirely eliminate the pathogens during comp...

Micellar growth of m-2-m type gemini surfactants (m=10, 12, 14) with higher chain length alcohols/amines (C6–C8) in the absence and presence of organic salts (sodium salicylate, sodium tosylate)

Abstract The micellar growth of dicationic gemini surfactants with the general formula CmH2m + 1(CH3)2 N+(CH2)2 N+(CH3)2CmH2m + 1, 2Br− as a function of alkyl chain length (m = 10, 12, 14) and effect of addition of alcohols (C6OH, C7OH, C8OH) and amines (C6NH2, C7NH2, C8NH2) in the absence and presence of organic salts (NaSal, NaTos) have been investigated by viscosity measurements at 30 °C. A simultaneous presence of organic salt and alcohol/amine induced aggregate morphologies in the gemini micellar systems by giving high viscosity values. As the chain length of the organic additive increases, the viscosity increases with increase in additive concentration and the extent of the effect followed the sequence: C6

Surface morphological and impedance spectroscopic studies on the interaction of polyethylene glycol (PEG) and polyvinyl pyrrolidone (PVP) with mild steel in acid solutions

The inhibition of mild steel corrosion in aerated acid mixture of 0.5 N H2SO4 and 0.5 N HCl solution was investigated using potentiodynamic polarization studies, linear polarization studies, electrochemical impedance spectroscopy, adsorption, and surface morphological studies. The effect of inhibitor concentration on corrosion rate, degree of surface coverage, adsorption kinetics, and surface morphology is investigated. The inhibition efficiency increased markedly with increase in additive concentration. The presence of PEG and PVP decreases the double-layer capacitance and increases the charge-transfer resistance. The inhibitor molecules first adsorb on the metal surface following a Langmuir adsorption isotherm. Both PEG and PVP offer good inhibition properties for mild steel and act as mixed-type inhibitors. Surface analysis by scanning electron microscopy (SEM) and atomic force microscopy (AFM) shows that PVP offers better protection than PEG.

Study on Preparation and Performance of Modified Polyvinyl Chloride-co-vinyl Acetate Microfiltration Membranes

In this paper, flat-sheet microfiltration membranes were prepared from modified polyvinyl chloride-vinyl acetate (VC-co-VAc) material with hydroxyl group, VC-co-VAc-OH, by phase inversion technique. The influences of casting solution composition (polymer concentration, additive types, and content) and preparation conditions (coagulation temperature, evaporation time of solvent, and the relative humidity in the environment) on pure water flux, retention, and pore size distribution were discussed. The results showed that casting solution composition and the membrane preparation conditions all have significant impacts on the performances of the membrane: on the one hand, in order to prepare membranes with high flux, either decrease the polymer concentration, or increase the PEG molecular weight or the coagulation temperature or the relative humidity can achieve it; on the other hand, with the increase of additive content, the pure water flux increased quickly, then decreased dramatically, while the effect of evaporation time were the opposite. And these results were confirmed by the SEM images. Furthermore, the microfiltration membranes, which were prepared under optimized conditions, were used to treat synthetic oilfield polymer-flooding wastewater, and good experimental results were obtained.