Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Sorption mechanism(s) of orthophosphate onto Ca(OH)2 pretreated bentonite
Δημιουργός/Συγγραφέας:	Markou G. Inglezakis V.J. Mitrogiannis D. Efthimiopoulos I. Psychoyou M. Koutsovitis P. Muylaert K. Baziotis I.
Εκδότης:	Royal Society of Chemistry
Ημερομηνία:	2016
Γλώσσα:	Αγγλικά
ISSN:	2046-2069
DOI:	10.1039/c5ra27638a
Περίληψη:	Bentonite was chemically pretreated with Ca(OH)2 to enhance orthophosphate phosphorus (OPP) sorption capacity (qe). The pretreatment resulted in an increase of qe from about 0.3 mg P per g to about 8 mg P per g at pH 7 and 25 °C, and of OPP concentration 100 mg P per L. The effects of solution pH, OPP concentration, sorbent dosage, and temperature on OPP sorption onto pretreated bentonite were investigated. The variation of initial pH (4-9) did not affect qe, however, re-adjustment of the final pH showed that the variation of the final pH had a significant positive effect on qe. The sorption kinetics showed a low rate, reaching half of qe in the first 4 h and equilibrium after 96 h. The calculated Langmuir qmax was 11.68 mg P per g. Thermodynamic analysis suggests that the sorption process is spontaneous and endothermic. Desorption of OPP was high in solutions of 0.1 M HCl and 0.01 EDTA-Na2 and reached 83% and 98%, respectively. We conclude that the predominant sorption mechanism for OPP uptake is inner-sphere surface complexation (ligand exchange). Other less important mechanisms such as surface precipitation and replacement of P5+ for Si4+ on the tetrahedral sites of montmorillonite may operate during the OPP uptake process by pretreated bentonite with Ca(OH)2.
Τίτλος πηγής δημοσίευσης:	RSC Advances
Τόμος/Κεφάλαιο:	6
Τεύχος:	27
Σελίδες:	22295-22305
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry
Αξιολόγηση από ομότιμους (peer reviewed):	Ναι
Κάτοχος πνευματικών δικαιωμάτων:	© The Royal Society of Chemistry 2016.
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο