Comparison of prehydration and polymer adding effects on Na activated Ca-bentonite by free swell index test

Sato, Kazuki; Barast, Gilles; Razakamanantsoa, Andry; Djéran-Maigre, Irini; Tanaka, Katsumi; Levacher, Daniel

doi:10.1016/j.clay.2016.10.009

Cited by 28 publications

(12 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The method of polymer modification is that the ionic polymer enters the montmorillonite interlayer because of its stronger affinity for the interlayer domain, so the ion exchange does not easily occur again, which may change the mineral structure and lead to the failure of the antiseepage function. Prolonged exposure of the modified Ca-bentonite to multispecies fluids disturbs the electronic equilibrium, causing a loss of hydraulic performance [28], and a similar conclusion is observed in this study. The effect of cation on the FSI of polymer-modified bentonite is less than that of sodium-modified bentonite.…”

Section: Free Swellsupporting

confidence: 87%

“…Various types of manufacturing processes were developed to reinforce the properties of Ca-bentonite such as hydraulic conductivity, swelling ability, and chemical resistance. These properties were enhanced by adding modifier to achieve the same hydraulic behavior as sodium bentonite with water [28]. As the modifier is divided into inorganic 8…”

Section: Relationship Between Fsi and Characteristic Parameters Of Nmrmentioning

confidence: 99%

See 1 more Smart Citation

Studies on Hydration Swelling and Bound Water Type of Sodium- and Polymer-Modified Calcium Bentonite

Wan

Guo

Hui

et al. 2020

Advances in Polymer Technology

View full text Add to dashboard Cite

Modified calcium bentonite (Ca-bentonite) is extensively used in engineered barrier systems (EBSs) for municipal and industrial disposal sites due to its high swelling potential and low hydraulic conductivity. However, few studies have focused on the micromechanism of hydration and swelling under the effect of inorganic chemical solution. In this study, free swell index (FSI) and the type and content of modified Ca-bentonite bound water under the inorganic chemical solution were quantitatively studied by using the free swell test and nuclear magnetic resonance (NMR). According to the results, modification of sodium and polymer significantly increases the FSI of Ca-bentonite, bringing it close to that of natural sodium bentonite. In addition, the chemical stability of polymer-modified bentonite is significantly higher than that of sodium-modified bentonite but less than that of natural Na-bentonite. The FSI of modified Ca-bentonite decreases with the increase of cation valence and ionic strength. T2 distribution curves of the two types of modified bentonite are three-peak curves. With the increase of ionic strength, the content of total water and permeated hydrated water (accounting for 69%–95%) in bentonite decreases gradually, whereas the surface hydration water (accounting for 2%–31%) and free water content (accounting for 0–15%) increase. A uniform linear relationship exists between the FSI and corresponding total peak area of NMR (independent of ion valence, concentration, and bentonite type). Furthermore, a linear relationship exists between the FSI of the same type of bentonite and the T2 relaxation time. Research results can provide data and theoretical basis for quantitative analysis and mechanism of the hydration swelling of bentonite.

show abstract

Section: Free Swellsupporting

confidence: 87%

Section: Relationship Between Fsi and Characteristic Parameters Of Nmrmentioning

confidence: 99%

Studies on Hydration Swelling and Bound Water Type of Sodium- and Polymer-Modified Calcium Bentonite

Wan

Guo

Hui

et al. 2020

Advances in Polymer Technology

View full text Add to dashboard Cite

show abstract

“…Some scholars had prepared multicomponent composites with bentonite-steel slag polymer to treat AMD. In 2016, Sato K modified Na-bentonite with polymer, which had a positive effect on the swelling of bentonite and improved its adsorption performance (Sato et al 2017). Merino D et al prepared amine modified polyacrylamide / bentonite composite (Am-PAA-B) by intercalation in situ polymerization to adsorb Cu 2+ in the wastewater, the removal rate reached 99.0% at pH of 5 [14].…”

Section: Multicomponent Composites With Bentonitesteel Slag Polymermentioning

confidence: 99%

RETRACTED ARTICLE: A technology review on treatment of acid mine drainage with bentonite–steel slag composite

et al. 2021

View full text Add to dashboard Cite

Acid mine drainage (AMD) which produced in the process of mining seriously pollutes the water resources and endangers the ecological environment due to its physicochemical characteristics, such as low pH, high salinity and high heavy metal concentrations. In recent decades, the treatment of AMD has become a key issue in the field of environmental protection. One important method of AMD treatment is adsorption method, and the selection of adsorbent is the key of this technique. Bentonite and steel slag are usually sintered at high temperatures to prepare bentonite–steel slag composite. AMD treatment with bentonite–steel slag composite, as a new adsorbent, is emerging as a promising treatment method by physical adsorption, ion exchange and chemical neutralization. The bentonite–steel slag composites mainly include bicomponent composite with bentonite–steel slag and multicomponent composite with bentonite–steel slag modifier. The author found that this important research question was rarely paid attention to, therefore, and the author combined with previous research and theories to promote the explanation of this problem. In this review, the technology of treatment of AMD with bentonite–steel slag composite is comprehensively discussed. Also, the role of its mechanism is also discussed in-depth. This paper provides a scientific reference on the remediation of contaminated environments.

show abstract

“…The flocculent showed a relatively high removal efficiency of the toxic metal present in low concentrations, which is also attributed to solubility suppression by the CaMg.2OH) 2 and sorption capacity of both bentonite clay and saw dust including intercalation and co-precipitation by primary flocs (Aboulhassan et al 2006). On the other hand, there is a propensity that the composite of saw dust with bentonite significantly ameliorated the spacing between the bentonite layers, improved the pore structure, swelling and sorption of the composite to avoid agglomeration as revealed in the studies conducted by Neelaveni et al (2019) and Sato et al (2016) using graphite and polymer combined with bentonite clay respectively. The removal efficiencies of Fe from the AMD sample using a combination of saw dust clay and CaMg.2(OH) 2 changed from a concentration of 933 ppm (raw AMD) to an increasing percentage removal in a range 42-70%, those for Cu and Ni also exhibit a change from 345 to 312 ppm to an increasing percentage removal trends 62-98 and 53-70% respectively.…”

Section: Resultsmentioning

confidence: 99%

The removal of turbidity and toxic metals in the AMD using a combination of saw dust, bentonite clay and synthetic CaMg.2(OH)2

Ntwampe

2021

Water Practice and Technology

View full text Add to dashboard Cite

Sets of experiments were conducted using 200 mL of synthetic acid mine drainage(AMD) into five 500 mL glass beaker, dosed with varying quantities of bentonite clay, saw dust and CaMg.2(OH)2 respectively and as a flocculent (bentonite clay, saw dust and CaMg.2(OH)2), mixed at 250 and 100 rpm for 2 and 10 mns respectively. The samples settled for 1 hour after which the pH, conductivity, turbidity, dissolved oxygen, oxidation reduction potential and toxic metals were measured. The turbidity removal of treated AMD samples treated with a flocculent (0–23 NTU) is lower compared to that of the samples treated with bentonite clay and saw dust (27–32 NTU). Results show 100% removal of Ni, moderate percentage removal of Fe and slightly lower percentage of Cu in treated AMD using a flocculent. Turbidity removal in treated AMD using a flocculent is higher compared to that of the samples treated with bentonite clay, saw dust or CaMg.2(OH)2. Treated AMD using flocculent has low Ca, Mg, Cl− and SO42− content (>84.8%). The SEM micrograph of the sludge of the sample with a combination of 1.5 bentonite clay, 1.5 g saw dust and 20 mL 0.025 M CaMg.2(OH)2 dosage shows optimal sorption of turbid materials.

show abstract

Comparison of prehydration and polymer adding effects on Na activated Ca-bentonite by free swell index test

Cited by 28 publications

References 27 publications

Studies on Hydration Swelling and Bound Water Type of Sodium- and Polymer-Modified Calcium Bentonite

Studies on Hydration Swelling and Bound Water Type of Sodium- and Polymer-Modified Calcium Bentonite

RETRACTED ARTICLE: A technology review on treatment of acid mine drainage with bentonite–steel slag composite

The removal of turbidity and toxic metals in the AMD using a combination of saw dust, bentonite clay and synthetic CaMg.2(OH)2

Contact Info

Product

Resources

About