Nurfer Güngör

The viscosity and zeta potential of bentonite dispersions in presence of anionic surfactants

Abstract The influence of surfactants on the flow behaviour of bentonite dispersions (2% w/w) is studied for two anionic surfactants, sodium dodecyl sulfate (SDS) and ammonium lauryl sulfate (ALS). In the range of 10 −4 –10 −2 mol/l, the surfactants show different effects on the viscosity and zeta potential of the bentonite suspension. The experimental results are discussed considering changes in the interlayer of the clay minerals.

Interactions of polyacrylamide polymer with bentonite in aqueous systems

Abstract The flow properties of natural Ca bentonite and Na bentonite–water systems were studied after adding an anionic polyacrylamide (PAM) polymer. The effect of the PAM has also been investigated at different quantities. The experimental results are discussed in terms of bentonite forms and concentration of PAM. Besides, measurement of rheological properties of Ca bentonite+PAM and Na bentonite+PAM systems have been examined in detail through XRD, FT-IR and DTA analyses.

The effect of SDS surfactant on the flow and zeta potential of bentonite suspensions

Abstract The influence of the surfactant on the flow behaviour of bentonite suspensions (2% w/w) was studied for an anionic surfactant, sodium dodecyl sulphate (SDS). In the range of 10 −4 –10 −2 mol/l, SDS was added to the bentonite water system in eight different concentrations and the observed result was the different effects on the viscosity, which is related to the interactions among particles and surfactant, particles and particles, and particles and water molecules. IR studies have been carried out in parallel to the viscosity and zeta potential studies. Based on the structural changes due to the SDS additions, the rheological and colloidal properties of the altered bentonite–water systems have been interpreted.

Effect of the adsorption of surfactants on the rheology of Na-bentonite slurries

Characteristic rheologic properties, such as shear stress, viscosity, yield point of Na-activated bentonite were studied after adding an anionic surfactant (linear alkyl benzene-sulfonate, LABS) and a cationic surfactant (distearly dimethyl ammonium chloride, DDAC). The effect of the surfactants also have been investigated at different quantities. The results have been discussed considering the types of additives and their concentrations.

Rheology and structure of aqueous bentonite-polyvinyl alcohol dispersions

The influence of polymer on flow behaviour of Balikesir, Turkey bentonite dispersions (2%, w/w) was studied for non-ionic polymer, polyvinyl alcohol (PVA). In a range of 3.3 × 106 −3.3 × 105 mol/l, PVA was added to the bentonite dispersions in different concentrations and its behaviour was observed on rheology parameters. Thixotropy was detected by a hysteresis loop of the flow curves. The data were interpreted taking into account the interactions of colloidal clay particles, bentonitic clay concentrations, structure, and concentrations of added PVA. The particle size analysis was explained by surface orientation of PVA to the clay particles dispersed in aqueous solution. Zeta potential determination also emphasized that PVA molecules got attached on the face and edge surface of clay particles. The morphology of bentonite dispersions was analysed by scanning electron micrograph (SEM). FTIR studies carried out in parallel to rheology studies showed that hydrogen bonds were formed between surface of the clay, and absorbed PVA molecules and adsorbed water. The presence of PVA did not prevent extensive swelling of bentonite.

Effect of the adsorption of cetylpyridinium bromide on the flow behaviour of bentonite dispersions

Abstract The adsorption of the cationic surfactant, cetylpyridinium bromide (CPBr), and the rheological behaviours of the CPBr-coated bentonite dispersions (0.1% w/v) are investigated in the concentration range of 0.01–10 mmol/l CPBr. The adsorption capacity and the influence of the cationic surfactant on the flow behaviours change with the nature of the exchangeable cations, i.e. Na+ and Ca2+, of the bentonite samples.

Effect of the adsorption of non-ionic polymer poly(vinyl)pyrolidone on the rheological properties of Na-activated bentonite

Rheological properties of Na-activated bentonite were studied after adding poly(vinyl)pyrolidone (PVP). The experimental results have been discussed considering bentonite types and concentrations of additives PVP. In the use of the bentonite clay sludges in industry, the addition of PVP polymer is recommended if an increase in viscosity is desired.

Effects of polyethyleneimine adsorption on rheology of bentonite suspensions

The influence of the cationic polymer, polyethyleneimine polymer (PEI) on the flow behaviour of bentonite suspensions (2%, w/w), was studied. XRD, zeta potential and adsorption studies were done together with rheological measurements. The addition of PEI at concentration ranges of 10-5-4.5 g/l and their rheological properties and stability of bentonite suspensions were studied. The adsorption rates for the bentonite suspensions are very fast. The XRD results showed that the PEG molecules did not intercalate into the layers of the clay.

Influences of Electrolytes, Polymers and a Surfactant on Rheological Properties of Bentonite–Water Systems

Characteristic rheological properties, such as viscosity, shear stress, yield point, gel strength and thixotropy, of natural Ca- bentonite and Na-peptized bentonite were studied after adding LiCl, KCl, CaCl2, MgCl2·6H2O electrolytes; (NaPO3)n, polyvinyl pyrolidone (PVP) polymers and an anionic surfactant (linear alkyl benzene sulphonate, LABS). Changes in flow properties under the influence of various additives at different quantities were investigated in these slurries. The experimental results are discussed in terms of bentonite forms, types and concentrations of additives and influence of exchangeable cations. Bivalent and monovalent cations display entirely different rheological properties in two groups of muds. Furthermore, the difference in the degree of activity of PVP polymer on the viscosity of two mud systems depend on the clay mineral structure. The slurry prepared with Na-bentonite contains a minimum number of tactoids and a maximum number of sheet-bearing clay particles, which reduces the surface area of the clay minerals and increases viscosity by adding PVP polymer.

Influence of Clay Surface Modification on Morphology and Rheology of Polyethylene Glycol/Montmorillonite Nanocomposites

The effects of surface modification of Na-montmorillonite (Na-MMT) on morphology and the rheological properties of polyethylene glycol/ organoclay nanocomposites are investigated. Dodecyltrimethylammonium bromide (DTABr) is used to modify the clay surface. Adsorption of DTABr on Na-MMT is monitored by zeta potential measurements. From zeta potential measurements, three DTABr concentrations, 1 × 10—3, 7.5 × 10— 3, and 5 × 10—2 mol/L, are chosen to fabricate the polyethylene glycol/organoclay composites. The morphology of three sets of organoclays (OMMT1, OMMT2, and OMMT3) is studied by X-ray diffraction (XRD) technique. The increase of basal spacing is found to be 0.2 nm as the DTABr concentration is increased to 7.5 × 10— 3 mol/L. The rheological properties of polyethylene glycol (PEG)/ organoclay nanocomposites are studied for three organoclays at different PEG concentrations. All nanocomposites show Bingham plastic flow behavior. The OMMT3 shows maximum viscoelastic properties in the polymer matrix. The morphology and electrokinetic properties of the PEG/organoclay nanocomposites are also investigated.