Investigating factors influencing polymer elution and the mechanism controlling the chemical compatibility of GCLs containing linear polymers

Molecular Dynamics Simulation of the Interaction within the Carboxymethyl Cellulose-Modified Montmorillonite Lamellae at Aggressive CuCl2 Concentrations

“…Conversely, Scalia et al (2014) reported that polymer elution was lower in more concentrated CaCl 2 solution, and the eluted polymer fraction decreased from 0.8 to 0.1 as CaCl 2 concentration increased from 0 to 500 mM . A nonmonotonic polymer elution was reported by Wireko and Abichou (2021) that the eluted polymer fraction increased from 20 to 44% as CaCl 2 concentration increased from 50 to 200 mM, while it decreased to 35% as CaCl 2 concentration increased to 500 mM . Based on the results in this study, apparently, formation of cation bridges between the polymer and MMT could prevent polymer elution, while elution resistance originated from cation bridges did not seem to change as the CuCl 2 concentration ranges from 200 to 800 mM due to the relatively constant contour area in Figure S2l–n.…”

“…69 A nonmonotonic polymer elution was reported by Wireko and Abichou (2021) that the eluted polymer fraction increased from 20 to 44% as CaCl 2 concentration increased from 50 to 200 mM, while it decreased to 35% as CaCl 2 concentration increased to 500 mM. 8 Based on the results in this study, apparently, formation of cation bridges between the polymer and MMT could prevent polymer elution, while elution resistance originated from cation bridges did not seem to change as the CuCl 2 concentration ranges from 200 to 800 mM due to the relatively constant contour area in Figure S2l− n. On the other hand, the coiling of the polymer did not increase continually as CuCl 2 increased, the CMC conformation extended as CuCl 2 increased from 200 to 800 mM. Therefore, it could be concluded that polymer elution resistance originated from cation bridges first increased as CuCl 2 concentration increased from 0 to 200 mM and then remained relatively constant as CuCl 2 concentration increased to 800 mM.…”

“…The existing hypothesized mechanisms include chelation and "scavenging", which are insufficiently substantiated either experimentally or numerically at the microscopic level. 2,8 Molecular dynamics (MD) simulation has become a complementary method to experimental studies to investigate the microscopic mechanisms of clay−polymer interactions. 9 In recent years, many MD researches of the clay−polymer composites have been conducted including the mostly used polymer types for the organo-modified engineering clay barriers, such as poly(acrylic acid) (PAA), 10 polyacrylamide (PAM), 10−13 poly(ethylene oxide) (PEO), 10,14−17 polyethylene glycol (PEG), 15,18−20 poly(vinyl alcohol) (PVA), 18 poly(dimethysiloxane) (PDMS), 21 chitosan, 11 polycarboxylate, 19 polycaprolactone (PCL), 22 cellulose acetate (CA), 23 guar gum, 10 and xanthan gum, 24 as summarized in Table 2.…”

A brief introduction to polymers and concepts of polymer modification of bentonite for barrier applications

“…15 A pearl necklace as shown in Figure 1 can illustrate the simple case of a flexible linear polymer chain as often used for the modification of clay liners. 11,16,17 Each bead represents a repeat unit. Polymers consist of hundreds to thousands of these repeat units.…”

Biopolymer-amended-kaolin as a Barrier for Tailing Disposal Facilities

“…The sealing of the voids upon hydration of bentonite due to osmotic potential is known as self-sealing ability. Although the performance of GB is extremely outstanding under hazardous and toxic contaminants, GB loses the selfsealing ability under the in uence of high strength salt solutions due to loss of osmotic potential and fails to overcome van-der-Waal's attraction for disintegration of granules into the individual particles [4,15,[23][24][25]. Thus, the barrier performance under high-ionic strength salt solutions is critical to contain all different wastes [15].…”