Search results for "Bentonite"

Water retention behaviour and microstructural evolution of MX-80 bentonite during wetting and drying cycles

2014

MX-80 bentonite used in engineered barrier systems would be subjected to wetting and drying cycles. To assess the response of the material under such circumstances, a comprehensive experimental characterisation of the water retention behaviour of compacted MX-80 granular bentonite was performed in this study. A new methodology is proposed to investigate this behaviour under a constant volume condition for specimens prepared at different dry densities. The material was subjected to different hydraulic paths, including cyclic variations of the water content. As a result, an irreversible modification of the retention behaviour was observed when the material approached a fully saturated state …

Solid-state NMR investigation on the interactions between a synthetic montmorillonite and two homopolypeptides.

2006

Abstract Interactions of two homopolypeptides (polylysine and polyglutamic acid) with a synthetic montmorillonite were studied by 1H MAS, 1H–27Al HETCOR and 1H–13C CP-MAS NMR experiments. 1H–27Al HETCOR with 1H spin-diffusion NMR appears to be a powerful probe for the identification of the polypeptide fragments, which interact with the montmorillonite interlayer surfaces. In particular, selective interactions were observed between the polypeptide side-chains and the montmorillonite octahedral aluminum atoms. 1H–13C CP-MAS NMR experiments were used to assess the dynamics of the two polypeptides through the measurement of the t1/2 characteristic time of selected carbons. Results indicate that…

Hydro-Mechanical Behaviour of a Sand-Bentonite Mixture for the Confinement of Nuclear Wastes

2019

The established concept for the protection of the biosphere from high-level nuclear wastes consists in the use of multi-barrier systems in deep geological repository, for which clayey geomaterials are key elements. Bentonite-based materials are selected as buffer and backfilling materials. Once in place, the barriers will be subjected to a series of severe loadings, including strong variations of suction (i.e. wetting and drying cycles). The paper presents selected results from a large ongoing research work to investigate the behaviour of bentonite-based materials in the context of nuclear waste disposal. In particular, the paper focuses on the response of a Sand/Bentonite mixture under dif…

Green Extraction of Polyphenols from Waste Bentonite to Produce Functional Antioxidant Excipients for Cosmetic and Pharmaceutical Purposes: A Waste-t…

2022

In an ever-growing perspective of circular economy, the development of conscious, sustainable and environmental-friendly strategies to recycle the waste products is the key point. The scope of this work was to validate the waste bentonite from the grape processing industries as a precious matrix to extract polyphenols by applying a waste-to-market approach aimed at producing novel functional excipients. The waste bentonite was recovered after the fining process and opportunely pre-treated. Subsequently, both the freeze dried and the so-called “wet” bentonites were subjected to maceration. PEG200 and Propylene Glycol were selected as solvents due to their ability to dissolve poly…

The New Life Of Exhausted Bentonite From The Grape Processing Industry: From Waste To Precious Resource To Produce Novel Raw Materials Enriched In Po…

Introduction: In an ever-growing perspective of circular economy, the development of conscious, sustainable and environmental-friendly strategies to recycle the waste products is the key point1. The exhausted bentonite, from the grape processing industries, could become a precious matrix to produce new pharmaceutical/cosmetic excipients enriched in functional polyphenols2. Materials & Methods: The exhausted bentonite recovered after the fining process (supplied by Bono&Ditta s.p.a., Campobello di Mazara TP, Italy) was stored at -20°C. Solid-liquid extractions on both freeze-dried and as-collected (wet) bentonite were carried out by using PEG200 or propylene glycol as solvents. The l…

Nanoparticles and their influence on radionuclide mobility in deep geological formations

2012

International audience; This article gives an overview of the current status of knowledge concerning the role of nanoparticles (inorganic and organic) in deep geological host rocks and the potential influence of these nanoparticles on radionuclide migration in far-field systems. The manuscript is not intended to be a full review paper or overview paper concerning nanoparticles, here the intention is to refer to recent publications but to highlight the progress made in the 6th framework project IP FUNMIG (Fundamental processes of radionuclide migration) and the open literature over the past 5 a concerning the process understanding of nanoparticle related issues in the three host rock formati…

Effectiveness of clays and copper products in the control of Bactrocera oleae (Gmelin)and Ceratitis capitata (Wiedemann) in organic farming

2008

Tests on the effect of clays (kaolin and bentonite) and copper products (hydroxide and oxychloride) in the control of olive fruit fly, Bactrocera oleae (Gmelin), and Mediterranean fruit fly, Ceratitis capitata (Wiedemann), were carried out from 2003 to 2006 in olive groves, and in 2005 and 2006 in organic orange orchards (early ripening cv. Navelina). Results demonstrate an efficacy of kaolin products in reducing attacks of Bactrocera oleae to olives and those of Ceratitis capitata to oranges. In olive groves, they gave similar or better results than copper hydroxide. Bentonite AG/W8 showed a significant reduction in punctures towards C. capitata. Bentonite products and BPLK kaolin are clea…

Development of novel secondary raw materials from grape juice fining waste as enriched excipients for oral care products and pharmaceuticals

2023

Development of secondary raw materials and oral care products starting from must fining waste

Bentonites with grafted aminogroups: Synthesis, protolytic properties and assessing Cu(II), Cd(II) and Pb(II) adsorption capacity

2019

Abstract Bentonites with grafted methylaminopropyl (NHCH3-Bent), aminopropyl (NH2-Bent), ethylenediaminopropyl (En-Bent) and diethylenetriaminopropyl (Dien-Bent) groups were synthesized by silylation procedure. The successful covalent grafting of silylating agents on the bentonite was confirmed by 29Si NMR, FTIR and thermal analysis. The effects of polar (ethanol) and non-polar (dioxane) solvents on grafting process were compared. The samples prepared in ethanol showed the increase of d001 value from initial 1.44 nm to 1.63–2.05 nm proportionally to the loading amount of grafted silane. However, an almost constant value of d001 (1.96–2.10 nm) was observed for all samples obtained in dioxane…