Green Technologies for the Defluoridation of Water

I: Properties, source, health and environmental risk assessment of fluoride

1. Sources and occurrence of fluoride in the environment

1.1. Fluoride in ambient air

1.2. Fluoride in food / foodstuffs

1.3. Fluoride in soil, agricultural crops and vegetables

1.4. Fluoride in water

2. Effects on human health

2.1. Intake and metabolism of fluoride

2.2. Dental fluorosis

2.3. Skeletal fluorosis

2.4. Neurological problems

2.5. Developmental Effects

2.6. Reproductive Effects

2.7. Endocrinological Effects

2.8. Gastrointestinal Effects

2.9. Carcinogenic Effects

3. Effects of fluoride on animals

4. Effects of fluoride on plants

5. Guidelines and standards of fluoride in drinking water

II: Approaches and analytical methods for determination of fluoride in water

1.1. Spectrophotometry

1.2. Anion exclusion chromatography

1.3. Flow injection analysis

1.4. Rapid photometric method

1.5. Potentiometry

1.6. Colorimetry

1.7. HPLC

1.8. Sensors

1.9. Overview of the methods, in terms of advantages and drawbacks

III: Conventional and advanced techniques for removal of fluoride from water

1. Traditional techniques for removal of fluoride from water

1.1. Fundamentals and theories

1.2. Coagulation and precipitation

1.3. Membrane separation

1.4. Ion exchange

1.5. Electrochemical process

1.6. Electro-dialysis

1.7. Adsorption

1.8. Others

1.9. Overview of the techniques, in terms of advantages and drawbacks

IV: Adsorption: A cost-effective green technology for removal of fluoride from water

1. Fundamentals of adsorption

2. Factors affecting adsorption

3. Adsorption modeling

3.1. Introduction

3.2. Isotherms

3.2.1. Henry’s Law

3.2.2. Monolayer adsorption and the Langmuir isotherm

3.2.3. Freundlich isotherm model

3.2.4. Langmuir-Freundlich models

3.2.5. Other isotherm models

3.3. Comparison of linear and nonlinear fitting of isotherms

3.3.1. Typical values of isotherm parameters for different adsorbate–fluoride systems

3.4. Kinetics

3.4.1. Adsorption reaction models

3.4.1.1. Pseudo 1st order model

3.4.1.2. Pseudo 2nd order model

3.4.1.3. General-order model

3.4.2. Empirical models

3.4.3. Avrami-fractional-order

3.4.4. Elovich chemisorption

3.4.5. Intraparticle diffusion models

3.4.5.1. Weber – Morris

3.4.5.2. Boyd models

3.4.5.3. Other models

3.4.6. Diffusional mass transfer models

3.5. Comparison of linear and nonlinear fitting of kinetics

3.6. Thermodynamics

3.7. Equilibrium constant

3.8. Thermodynamic equilibrium constant

3.9. Linear and nonlinear van´t Hoff equation

V: Adsorbents for removal of fluoride from water

1. Adsorbents types for fluoride removal

1.1. Natural adsorbents

1.1.1. Alumina and alumina-based adsorbents

1.1.2. Calcium based adsorbents

1.1.3. Clay and bentonite

1.1.4. Pumice

1.1.5. Zeolite

1.1.6. Other natural materials

1.2. Derived adsorbents

1.3. Metal based adsorbents

1.4. Carbon based adsorbents

1.4.1. Activated carbon

1.4.2. Carbon nanotube

1.4.3. Graphene/Graphene oxide

2. Waste based adsorbents

2.1. Agricultural waste adsorbents

2.2. Industrial waste adsorbents

2.3. Building materials

3. Bio-sorbents

3.1. Biopolymers - based adsorbents

3.2. Biomass (algal and fungal biomass)

3.3. Chitin - chitosan derivatives

3.4. Other bio-sorbents

4. Nanoparticles and Nanocomposites based adsorbents

5. Methods for desorption / regeneration of adsorbents and their performance

VI: Techno-economic assessment of de-fluoridation of water

1. Analysis of scaling aspects from lab-scale to pilot-scale and further to industrial scale

2. Techno-economic assessment of different conventional and non-conventional technologies

VII: Global water challenges and future perspectives

1. Future prospects and opportunities in handling water related issues