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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 Αναστασίου, Μαρίνα Μ.
Thesis advisor Δημάδης, Κωνσταντίνος
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.
Language Greek
Subject APTES
CPTMS
Calcium (Ca2+)
Hardness
Magnesium (Mg2+)
Organosilane
TESPSA
Ασβέστιο (Ca2+)
Μαγνήσιο (Mg2+)
Νερό
Οργανοσιλάνιο
Σκληρότητα
Υδρογέλη
Issue date 2023-11-23
Collection   School/Department--School of Sciences and Engineering--Department of Chemistry--Post-graduate theses
  Type of Work--Post-graduate theses
Permanent Link https://elocus.lib.uoc.gr//dlib/e/b/5/metadata-dlib-1699950882-503529-11723.tkl Bookmark and Share
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