Synthesis and rheological properties of cation-exchanged Laponite suspensions

Abstract

In this paper we report our new approach to synthesize cationexchanged Laponite suspensions. General observations of the prepared samples indicated that an aqueous suspension of 1 wt% Laponite retained its free flowing liquid phase characteristics even after aging for several weeks. When bivalent cationic metals (Cu, Co, Ni) were ablated into the suspension, the strong charge of the crystal face was reduced and, on standing, the suspension gelled becoming highly viscous. This solgel transition was induced by the formation of a spacefilled structure due to both van der Waals and electrostatic bonds between the pos itively charged rims and negatively charged faces. Rheological properties of such prepared suspensions were measured using a Brookfield DV1I Pro Viscometer with a small sample adapter (SSA18/13RPY). The yield strengths of 2.2 N/m 2 ,3.2 N/m 2 , and 1.7 N/m 2 were measured for Ni, Co, and Cumodified Laponite suspensions, respectively. These yield strengths are sufficiently high for suspending weighting materials such as barite which requires the gel strength of about 0.5 N/m 2 .Published by Elsevier B .V.

Enhancement of adsorption ability of calcium alginate gel beads towards Pd(II) ion. A kinetic and equilibrium study on hybrid Laponite and Montmorillonite–alginate gel beads

“…From a structural point of view, Laponite is a synthetic hectorite, which is highlighted by the presence of octahedral sheets containing Mg 2+ and Li + ions sandwiched between tetrahedral silica sheets. The presence of a certain amount of Li + ions in place of Mg 2+ produces a negative charge on the face, counterbalanced by sodium ions that can undergo exchanging phenomena towards metallic cations (Mosser et al, 1997;Phuoc et al, 2009), or cationic dyes (Arbeloa et al, 1998;De Lisi et al, 2007) (Sciascia et al, 2011). The diameter of Montmorillonite primary layer is typically about 0.8 μm.…”

Enhancement of Static and Dynamic Sag Performance of Water-Based Mud Using a Synthetic Clay

“…While the samples with 0.5 and 0.75 lb/bbl of laponite showed a continuous increase in the gel strength with time, the higher concentration of laponite yielded higher gel strength values (Figure ). The increase in gel strength was induced by the electrostatic bonds between laponite particles and laponite and xanthan polymer particles, resulting in a stronger and quick gel structure. , The gel structure helps suspend the weighting material and the drilled cuttings when the circulation is stopped. ,, The high values of gel strength require more pumping pressure to start the flow; thus, if the pressure required to break the gel exceeds the maximum pump pressure, drilling fluid formulation should be optimized by diluting the mud or adding thinners to attain favorable rheology at such conditions …”

“…Clays and polymers are added to increase the drilling fluid viscosity. , However, these additives have some limitations. For instance, polymers degrade at high temperatures, affecting the drilling fluid viscosity, and flocculation of bentonite fluids was also observed at high temperatures …”

Effect of Shear History on Rheology of Time-Dependent Colloidal Silica Gels

“…The change with time of the rheological properties of pharmaceutical formulations may influence the controlled release of loaded drugs, defining their therapeutic efficacy and bioavailability [6]. In colloid science, the decrease of viscosity of gels and suspensions of colloidal particles when shear is applied make them key components in mining, ceramic, and coating industries [7,8,9,10,11]. Moreover, time dependent colloidal gels are an emerging alternative in biotechnology for cell culture [12] and in rocket propulsion systems [13,14,15].…”