Salifu Fluoride Removal from Groundwater by Adsorption Technology

Erscheinungsjahr 2017
ISBN: 978-1-351-19997-1
Verlag: Taylor & Francis
Format: EPUB
Kopierschutz: Adobe DRM (»Systemvoraussetzungen)

E-Book, Englisch, 300 Seiten

In the Eastern corridor of Northern region of Ghana, presence of high fluoride concentration in the groundwater has made many drilled boreholes unusable for drinking. Little is, however, known about the factors contributing to the occurrence of high fluoride in this part of Ghana and it’s spatial distribution. Treatment of the fluoride-contaminated groundwater by adsorption is also hampered by the lack of suitable adsorbents that are locally available.

Based on principal component analysis, and saturation indices calculations, this thesis highlights that, the predominant mechanisms controlling the fluoride enrichment probably include calcite precipitation and Na/Ca exchange processes, both of which deplete Ca from the groundwater, and promote the dissolution of fluorite. The mechanisms also include F-/OH- anion exchange processes, as well as evapotranspiration processes which concentrate the fluoride ions, hence increasing its concentration in the groundwater. Spatial mapping showed that the high fluoride groundwaters occur predominantly in the Saboba, Cheriponi and Yendi districts.

The thesis further highlights that, modifying the surface of indigenous materials by an aluminium coating process, is a very promising approach to develop a suitable fluoride adsorbent. Aluminum oxide coated media reduced fluoride in water from 5. 0 ± 0.2 mg/L to = 1.5 mg/L (which is the WHO health based guideline for fluoride), in both batch and continuous flow column experiments in the laboratory. Kinetic and isotherm studies, thermodynamic calculations, as well as analytical results from Fourier Transform Infrared Spectroscopy and Raman spectroscopy, suggest the mechanism of fluoride adsorption onto aluminium oxide coated media involved both physisorption and chemisorption processes.

Field testing in a fluoritic community in Northern Ghana showed that the adsorbent is also capable of treating fluoride-contaminated groundwater in field conditions, suggesting it is a promising defluoridation adsorbent. The adsorbent also showed good regenerability potential that would allow re-use, which could make it practically and economically viable. Additional research is, however, required to further increase the fluoride adsorption capacity of developed adsorbent.

Autoren/Hrsg.

Salifu, Abdulai

Fachgebiete

• Geowissenschaften Umweltwissenschaften Umweltwissenschaften
• Technische Wissenschaften Umwelttechnik | Umwelttechnologie Wasserversorgung, Wasseraufbereitung

Inhaltsverzeichnis

1 General introduction
1.1 Background
1.2 Groundwater, fluoride contamination, the benefits and pathophysiology
1.3 High fluoritic regions
1.4 Available fluoride removal technologies
1.5 Aim and scope of the study
1.6 Research objectives
1.7 Outline of the thesis
References

2 Fluoride occurrence in groundwater in the Northern region of Ghana
Abstract
2.1 Background
2.2 Occurrence and hydrogeochemistry of fluoride
2.3 The study area
2.4 Study methodology
2.5 Results and Discussions
2.6 Conclusions
References

3 Drinking water defluoridation using aluminium (hydr) oxide coated pumice: Synthesis, equilibrium, kinetics and mechanism
Abstract
3.1 Background
3.2 Materials and Methods
3.3 Results and discussions
3.4 Conclusions
References

4 Laboratory-scale column filter studies for fluoride removal with aluminum (hydr) oxide coated pumice, regeneration and disposal
Abstract
4.1 Background
4.2 Material and methods
4.3 Results and Discussions
4.4 Modeling of breakthrough profiles
4.5 Fluoride adsorption performance of RAOCP and comparison with that of AOCP
4.6 Leaching test for waste (spent) AOCP for safe disposal
4.7 FTIR and thermodynamic analysis for insight into fluoride removal mechanism by RAOCP
4.8 Conclusions
References
Abstract

5 Fluoride removal from drinking water using granular aluminium-coated bauxite as adsorbent: Optimization of synthesis process conditions and equilibrium study
5.1 Background
5.2 Material and Methods
5.3 Results and discussion
5.4 Conclusions
References

6 Aluminol (Al-OH) fuctionalized wood charcoal for treatment of fluoride-contaminated groundwater: Effect of wood source, particle size, surface acidity-basicity and field assessment
Abstract
6.1 Background
6.2 Materials and Methods
6.3 Results and Discussion
6.4 Conclusions
References

7 General Conclusions
7.1 Overall conclusions and perspective
7.2 Fluoride occurrence in groundwater in the Northern region of Ghana
7.3 Drinking water defluoridation using aluminum (hydr)oxide coated pumice: Synthesis, equilibrium, kinetics and mechanism
7.4 Laboratory-scale column filter studies for fluoride removal with aluminum (hydr)oxide coated pumice: Filter runs with freshly synthesized and regenerated adsorbent and options for disposal of fluoride-saturated adsorbent
7.5 Fluoride removal from drinking water using granular aluminum-coated bauxite as adsorbent: Optimization of synthesis process conditions and equilibrium study
7.6 Groundwater defluoridation using aluminol (Al-OH) fuctionalized wood charcoal: Effect of wood source, particle size and field assessment
7.7 General outlook, limitations and recommendations

Über Autor(innen)

Abdulai Salifu is a Civil and Environmental Engineer, and obtained his BSc. degree (Civil Engineering) from the Kwame Nkrumah University of Science and Technology (KNUST), Kumasi, Ghana. He obtained his Post-Graduate diploma degree (passed with distinction) in Community Water Supply and Sanitation, from Loughborough University of Technology (LUT), England (U.K) and his MSc. degree in Environmental Engineering from the University of Newcastle upon Tyne, England (U.K). He worked for several years in the water sector in Ghana as a Water and Sanitation Engineer, where he worked in multi-disciplinary team professionals comprising of; Hydrogeologist, Sociologists, Health and Hygiene Education Specialist, IT Specialist and Planners, involved mostly in the provision of water supply and sanitation facilities as well as health/hygiene education to rural communities and small urban towns. He was involved in the planning and implementation of several water and sanitation projects in the Northern region of Ghana, financed by several External Support Agencies (ESAs), including the World Bank, European Union (EU), Agence Francais de Developpment (AFD), UNICEF, Japanese International Corporation Agency (JICA) and the Canadian Development Agency (CIDA).