Post-graduate theses
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Identifier |
000460366 |
Title |
Προσρόφηση κατιόντων ασβεστίου και μαγνησίου σε υδρογέλες Laponite-RD : εφαρμογές στην αποσκλήρυνση νερού |
Alternative Title |
Adsorption of calcium and magnesium cations on Laponite-RD Hydrogels: applications in water softening |
Author
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Αναστασίου, Μαρίνα Μ.
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Thesis advisor
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Δημάδης, Κωνσταντίνος
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Abstract |
Water Hardness is one of the major factors affecting water quality. Water
hardness is the result of insoluble Calcium (Ca2+) and Magnesium (Mg2+) salts
formation. Accumulation of these salts on household appliances and pipes
results in scale formation, and, at the industrial level impacts the smooth
operation of the system and the quality of the final product. In order to eliminate
those risks, water processing and softening is necessary. The process of water
softening so far, consists of the addition of chemical compounds which,
however, increase the concentration of certain ions in water, resulting in the
production of sludge about twice the amount of the removed hardness. The
present research aims in finding an environmentally friendly adsorbent for
removing the major cations responsible for water hardness, Calcium and
Magnesium. For this reason, hydrogels based on Laponite®-RD were studied
and evaluated. The nature of Laponite®-RD, as a synthetic hectorite, and its
ability to hydrate when mixed with water, developing charged moieties on the
faces and edges of its nanodiscs, makes it an effective, and environmentally
friendly adsorbent. After studying the hydrogels’ chemical stability and some
encouraging adsorption results of Calcium and Magnesium cations, kinetic
studies were conducted concerning the effect of other factors on adsorption.
The factors studied were, i. the hydrogel’s concentration, ii. the cation’s
concentration in the supernatant, iii. both the hydrogel and the supernatant’s
pH, and iv. the system’s temperature. All the above variables proved to have
an effect on the system’s adsorption capacity. Lastly, attempts of grafting the
clay’s surface were conducted by taking advantage of its charged surfaces by
adding Poly(Acrylic Acid) and the organosilanes: TESPSA (3-
(triethoxysilyl)propyl succinic anhydride), CPTMS ((3-
chloropropyl)trimethoxysilane) and APTES ((3-aminopropyl)triethoxysilane).
The approach was based on the concept of adding different functional groups
that can change the overall charge of the exposed nanoparticle surface of
Laponite®-RD, affecting the adsorption capacity of the clay.
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Language |
Greek |
Subject |
APTES |
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CPTMS |
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Calcium (Ca2+) |
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Hardness |
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Magnesium (Mg2+) |
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Organosilane |
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TESPSA |
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Ασβέστιο (Ca2+) |
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Μαγνήσιο (Mg2+) |
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Νερό |
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Οργανοσιλάνιο |
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Σκληρότητα |
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Υδρογέλη |
Issue date |
2023-11-23 |
Collection
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School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
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Type of Work--Post-graduate theses
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Permanent Link |
https://elocus.lib.uoc.gr//dlib/e/b/5/metadata-dlib-1699950882-503529-11723.tkl
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Views |
935 |
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