Defluoridation of groundwater using aluminum-coated bauxite: Optimization of synthesis process conditions and equilibrium study.
There is no known effective treatment for fluoride-related health disorders, hence prevention through water defluoridation is necessary. This study explored the possibility of modifying the physico-chemical properties of bauxite, a locally available material in many countries including Ghana, by thermal treatment and an aluminum coating, for water defluoridation. The study mainly focused on investigating the effects of varying synthesis process conditions on the defluoridation efficiency of Granular Aluminum Coated Bauxite (GACB). GACB performed better than raw bauxite (RB) and was able to reduce fluoride concentration in groundwater from 5 ± 0.2 mg/L to ≤ 1.5 mg/L, World Health Organization (WHO) guideline. Based on nonlinear Chi-square (χ(2)) analysis, the best-fitting isotherm model for the fluoride-GACB system was in the order: Freundlich > Redlich-Perterson ≈ Langmuir > Temkin. The fluoride adsorption capacity of GACB (qmax = 12.29 mg/g) based on the Langmuir model was found to be either comparable or higher than the capacities of some reported fluoride adsorbents. Aluminum (Al) coating procedures optimized in this study could therefore be a useful approach for synthesizing an effective fluoride adsorbent using bauxite, a locally available material. Kinetic and isotherm analysis, thermodynamic calculations, as well as FTIR and Raman analysis suggested the mechanism of fluoride adsorption onto GACB was complex and involved both physical adsorption and chemisorption processes.
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands; Community Water and Sanitation Agency, P.O. Box 810, Tamale, Ghana; Delft University of Technology, Delft, The Netherlands. Electronic address: abdulaisalifu@yahoo.com.
Abdulai
A
Salifu
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands.
Branislav
B
Petrusevski
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands.
Emmanuel S
ES
Mwampashi
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands.
Iddi A
IA
Pazi
Patel College of Global Sustainability, University of South Florida, Tampa, USA.
Kebreab
K
Ghebremichael
Kwame Nkrumah University of Science and Technology, Kumasi, Ghana.
Richard
R
Buamah
King Abdulla University of Science and Technology, Saudi Arabia.
Cyril
C
Aubry
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands; King Abdulla University of Science and Technology, Saudi Arabia.
Gary L
GL
Amy
UNESCO-IHE, P. O Box 3015, 2601 DA, Delft, The Netherlands; Delft University of Technology, Delft, The Netherlands.
Maria D
MD
Kenedy
D000327:Adsorption; D000535:Aluminum / Q000737:chemistry*; D000537:Aluminum Oxide / Q000737:chemistry*; D005459:Fluorides / Q000032:analysis / Q000737:chemistry*; D005869:Ghana; D060587:Groundwater / Q000737:chemistry*; D007700:Kinetics; D017550:Spectroscopy, Fourier Transform Infrared; D013059:Spectrum Analysis, Raman; D013816:Thermodynamics; D014874:Water Pollutants, Chemical / Q000737:chemistry; D018508:Water Purification / Q000379:methods*
D014874:Water Pollutants, Chemical; D000535:Aluminum; D000537:Aluminum Oxide; D005459:Fluorides
Adsorption; Aluminum; Bauxite; Fluoride; Groundwater defluoridation; Surface modification