Effect Of Hydrophilic Additives Research Articles

Industrial wastewater treatment using PES UF membranes containing hydrophilic additives: Experimental and modeling of fouling mechanism

In order to acquire preferred structure and performance, the effects of different hydrophilic additives, including triethylene glycol (TEG), polyethylene glycol (PEG), polyvinylpyrrolidone ( PVP ) at various concentrations, and coagulation bath temperature (CBT) on the morphology and performance of polyethersulfone (PES) ultrafiltration (UF) membranes were studied. The PES membranes were fabricated via non-solvent induced phase separation (NIPS) technique, and their performances were measured in terms of pure water flux (PWF), the flux of synthetic oil/water (O/W) emulsion, and industrial oily and textile wastewater, and oil rejection. Additionally, the morphology and hydrophilicity of the membranes were characterized by the SEM and water contact angle (CA) tests, respectively. The results revealed that the morphology and structure of the PES membranes depend on the type and concentration of the additive in the casting solution, as PES/PVP membranes had a denser structure than the PES/TEG and PES/PEG membranes. Besides, increasing CBT from 25 °C to 45 °C leads to the formation of a membrane with higher porosity, larger pores, higher water permeability, and lower oil rejection. The membrane containing 5%wt of TEG showed the best separation performance for treating synthetic and industrial wastewaters. Moreover, modeling of the flux decline using Hermia’s model and second kind standard blocking indicated the gel layer formation is the dominant fouling mechanism of the UF process of the oily wastewaters. • Effect of hydrophilic additives on morphology of PES UF membrane was investigated. • Effect of different CBTs on microstructure and performance of PES membranes was examined. • Optimal membrane exhibited an appropriate performance for treating refinery and textile industrial wastewaters. • Hermia’s model was applied to ascertain the governing fouling mechanisms.

Improved anti-organic fouling of polyvinyl chloride-based heterogeneous anion-exchange membrane modified by hydrophilic additives

Organic fouling – which generally gives a more severe effect on anion-exchange membranes (AEMs) – leads to performance degradation of electro-membrane processes. In this work, polyvinyl chloride (PVC)-based AEM was prepared by a solution casting method. Three AEMs were modified by different hydrophilic additives, namely polyethylene glycol 400 (PEG400), polyethylene glycol 1000 (PEG1000), and ZnO nanoparticles (M2-M4 membranes). Then, the properties of these modified membranes were compared to the pristine membrane (M1 membrane). The effect of hydrophilic additives on the anti-organic fouling properties of modified membranes was investigated during a simple electrodialysis test of feed water containing humic substances. The results of chemical structure analysis show that the additives are successfully incorporated in the membrane matrix. The presence of the hydrophilic additive in the membrane matrix increases membrane conductivity. The highest increase in conductivity is obtained by the addition of PEG400 (up to 50 %). Meanwhile, water uptake, ion-exchange capacity, and water contact angle of the modified membranes are insignificantly changed. In addition, the additives can improve membrane resistance toward organic fouling. The introduction of additive can suppress the increasing rate of membrane areal resistance by ∼60 %.

An investigation of the effect of methyl cellulose and sodium polyacrylate on the hydrosorption properties of a vulcanisate based on chloroprene rubber*

The effect of hydrophilic additives – MC-2000 methyl cellulose and sodium polyacrylate – on the properties of a vulcanisate based on Neoprene W was studied. The rubber mixes were prepared in two stages: at the first stage, hydrophilic additives were introduced into the rubber; at the second stage, the remaining ingredients were introduced. Vulcanisation was carried out at a temperature of 150°C for 30 min. The viscosity of the rubber mixes, M, was measured at 120°C on an MVR 3000 Basic viscometer (MonTech), and the vulcanisation characteristics and vulcanisation rate, v, were measured on an MDR 3000 Basic rheometer (MonTech) at 170°C in accordance with ASTM D2084-79. From the results of these measurements it follows that, with the combined use of methyl cellulose and sodium polyacrylate, there is a synergistic reduction in M and in the vulcanisation rate of the rubber mixes. A vulcanisate containing both hydrophilic additives possesses the best hydrosorption properties and has satisfactory physicomechanical properties (nominal tensile strength, elongation at break, hardness, and tear strength). The values of these properties and their changes on exposure of the vulcanisate to distilled water (70°C, 24 h) meet the requirements laid down for water-swelling rubber sealing elements.

Elastomer Seals for Oil Production Equipment

The technology of creating water-swellable elastomeric materials for making packer seals usable in the oil production industry is discussed. The effect of hydrophilic additives on the degree of swelling of ethylene-propylene based elastomers in water is studied. Mathematical modeling methods are used to make a predictive estimation of the maximum degree of swelling and rate constants of the swelling process as a function of the composition of water-swellable elastomer composites.

Effect of hydrophilic additives on volumetric and viscosity properties of amino acids in aqueous solutions at T = (283.15 to 333.15) K

Apparent molar volumes and partial molar volumes at infinite dilution, V¯2∘ for amino acids (glycine, l-valine, l-leucine, l-phenylalanine, and l-aspargine) aqueous solutions in sucrose (0.05 to 0.2 (w/w)), urea (0.05), 2,3-butane diol (0.05) and 2-butoxyethanol (0.05) as additives have been calculated from the experimental densities at T=(283.15 to 233.15)K. Limiting partial molar expansibilities, E2∘, side chain partial molar volumes, V¯2,tr∘ and transfer volumes (from water to aqueous additive environment), ΔVtr∘ for both the amino acids and their side chains have also been calculated. Relative viscosities for same systems were also calculated over the same temperature range and were analyzed in terms of Jones–Dole equation to calculate B-coefficients. The analysis of volumetric functions and B-coefficients suggests that the solute–co-solute interactions are more favored at elevated temperatures and in presence of high concentration of sucrose. Otherwise the hydrophobic side chains facilitate the solute–solute interactions and also time induced hydrophobic hydration in the bulk water.

Effect of hydrophilic substances on liberation of quinidine from starch—methylcellulose spheres

The spheres were prepared by the desolvation technique combined with gravitational sedimentation of droplets of methylcellulose gel suspensions with the addition of 25% quinidine adsorbate on the potato starch and 5% hydrophilic agents such as Span 80, Tween 60, glyceryl monostearate or PEG 2000 instilled into a desolvation liquid (saturated sodium acetate:paraffin liquid:heptane 1:1:1, v/v/v) through a standardized capillary.As follows from the physicochemical studies the sphericity (Sp) changed within the range 1.020–1.314, the porosity (P) was 19.1–66.5% and the loading efficiency was 35.10–67.07%. The release studies show that the dissolution efficiency after 60 min (DE60) in acidic medium was 78.6% for quinidine and 52.6–63.4% for the spheres; in phosphate buffer pH 6.8 DE60 was 32.4% for quinidine, but ranged within 16.3–26.0% for the spheres. The release of the drug from the spheres was fast and it was slightly difference (the loaded drug was released within 60 min) in acidic medium, while differentation of release in the phosphate buffer made it possible to evaluate the effect of hydrophilic additives on the dissolution rate.The general process of release can be described by the modified Higuchi equation Mt*=K0·(t−TD) , which facilitates the analysis of the theoretical amount of the released substance Mt* depending on the zero-order dissolution rate constant K0 and the dissolution lag time (TD). Accordingly, spheres with sustained release can be most effectively produced by addition of PEG 2000. These spheres are characterized by Sp = 1.035, P = 60.2% and a loading efficiency of quinidine 67.07%. The release in acidic medium proceeds with K0 = 3.857 mg·min−0.5 and TD = 6.21 min, in phosphate buffer K0 was 1.293 rng·min−0.5 and TD = 7.14 min. These parameters were of less importance for the other formulations. The modified Higuchi equation gives information about the parameters of drug released.