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Defluoridation of drinking water by calcined MgAl-CO"3 layered double hydroxides [An article from: Desalination]
Book Details
Author(s)L. Lv
PublisherElsevier
ISBN / ASINB000PDYRHY
ISBN-13978B000PDYRH2
AvailabilityAvailable for download now
Sales Rank99,999,999
MarketplaceUnited States 🇺🇸
Description
This digital document is a journal article from Desalination, published by Elsevier in 2007. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.
Description:
This work used calcined MgAl-CO"3 layered double hydroxides (CLDH) to remove fluoride with the reconstruction of their original layered structure in the presence of appropriate anions. The influences of pH of aqueous solution, dosage of CLDH and initial fluoride concentration on the distribution coefficient of fluoride with CLDH were investigated. The maximum distribution coefficient takes place at pH 6.0, 2.0 g/1.8 L CLDH dose, and 50 mg F^-/L. It was found from the equilibrium investigation that the defluoridation capacity decreases with increased temperature, which shows that the uptake process is exothermic in nature. The data of fluoride removal fitted well into the linearly transformed Langmuir. Thermodynamic parameters including @DG^0, @DH^0 and @DS^0 were calculated. The values of @DG^0 at 30, 40, 50 and 60^oC were -17.18, -17.55, -17.60 and -17.76 kJ/mol, indicating the spontaneous nature of defluoridation. The negative value of @DH^0 (-11.67 kJ/mol) confirms the exothermic nature of defluoridation. The positive value of @DS^0 (18.40 J/mol/K) suggests the increased randomness at the solid/solution interface for the uptake of fluoride onto CLDH. The mechanism of defluoridation was confirmed by powder X-ray diffraction and TG-MS.
Description:
This work used calcined MgAl-CO"3 layered double hydroxides (CLDH) to remove fluoride with the reconstruction of their original layered structure in the presence of appropriate anions. The influences of pH of aqueous solution, dosage of CLDH and initial fluoride concentration on the distribution coefficient of fluoride with CLDH were investigated. The maximum distribution coefficient takes place at pH 6.0, 2.0 g/1.8 L CLDH dose, and 50 mg F^-/L. It was found from the equilibrium investigation that the defluoridation capacity decreases with increased temperature, which shows that the uptake process is exothermic in nature. The data of fluoride removal fitted well into the linearly transformed Langmuir. Thermodynamic parameters including @DG^0, @DH^0 and @DS^0 were calculated. The values of @DG^0 at 30, 40, 50 and 60^oC were -17.18, -17.55, -17.60 and -17.76 kJ/mol, indicating the spontaneous nature of defluoridation. The negative value of @DH^0 (-11.67 kJ/mol) confirms the exothermic nature of defluoridation. The positive value of @DS^0 (18.40 J/mol/K) suggests the increased randomness at the solid/solution interface for the uptake of fluoride onto CLDH. The mechanism of defluoridation was confirmed by powder X-ray diffraction and TG-MS.
