severity condition muscles become inactive and paralysed, other problems are joint
crippling deformities, increase spinal cord density crippling deformities, neurological defects (Annadurai et al. 2014). Skeletal fluorosis may occur with a high F
movement from water and other dietary factors. Also, thyroid disorder, growth
retardation, kidney problem and even death can occur. F move from soil to root
through the diffusion process. F in high concentrations has adverse effects on plants
such as necrotic lesion, chlorosis, leaf tips and burning edges. Other physiological
parameters also disturbed such as root length, shoot length, chlorophyll a, and
chlorophyll b content, enzyme activity, seed germination rate. F adverse effects in
different plants were observed such as in Cyamopsis tetragonoloba (cluster bean),
Populus deltoides (poplar), Cicer arietinum (Bengal gram), Oryza sativa (paddy)
and Vigna radiata (mung bean) (Baunthiyal and Ranghar 2015).
6.4
Available Technologies for Removing Fluoride
There are different defluoridation technologies investigated for providing safe drinking water for the F-affected populations. It is described as “the downward adjustment
of level of F in drinking water to the optimal level” (Singh et al. 2016). Various
techniques were available throughout the world for F removal from the water.
6.4.1 Adsorption
Adsorption is an endothermic and mass transfer process that accumulates a material
or substance from liquid phase to the solid surface. The existence of special
functional groups on the adsorbent surface provides interaction with heavy metal
which leads to the adsorptive removal of metals from water. Popular adsorbents are
natural fibres, zeolite and activated carbon; they suffer from low adsorption capacity,
low selective sorption and unsatisfactory regeneration capability. Nowadays innovative adsorbents are metal oxide nanoparticles, CNT, graphene and others which
have been developed to overcome these problems (Khulbe and Matsuura 2018).
Filtration process requires high pressure and more expensive rather than adsorption.
Adsorption process is a prominent, economic, convenient and simple activity. In an
experiment, zirconium nanoparticles embedded in a hollow PSF membrane
demonstrated a high adsorption potential for F removal from aqueous (He et al.
2014). Adsorption kinetics and isotherms are useful in testing adsorbent efficiency
and defluoridation ability (Smitha and Thampi 2017).
6 Fluoride Remediation Using Membrane Processes
179
crippling deformities, increase spinal cord density crippling deformities, neurological defects (Annadurai et al. 2014). Skeletal fluorosis may occur with a high F
movement from water and other dietary factors. Also, thyroid disorder, growth
retardation, kidney problem and even death can occur. F move from soil to root
through the diffusion process. F in high concentrations has adverse effects on plants
such as necrotic lesion, chlorosis, leaf tips and burning edges. Other physiological
parameters also disturbed such as root length, shoot length, chlorophyll a, and
chlorophyll b content, enzyme activity, seed germination rate. F adverse effects in
different plants were observed such as in Cyamopsis tetragonoloba (cluster bean),
Populus deltoides (poplar), Cicer arietinum (Bengal gram), Oryza sativa (paddy)
and Vigna radiata (mung bean) (Baunthiyal and Ranghar 2015).
6.4
Available Technologies for Removing Fluoride
There are different defluoridation technologies investigated for providing safe drinking water for the F-affected populations. It is described as “the downward adjustment
of level of F in drinking water to the optimal level” (Singh et al. 2016). Various
techniques were available throughout the world for F removal from the water.
6.4.1 Adsorption
Adsorption is an endothermic and mass transfer process that accumulates a material
or substance from liquid phase to the solid surface. The existence of special
functional groups on the adsorbent surface provides interaction with heavy metal
which leads to the adsorptive removal of metals from water. Popular adsorbents are
natural fibres, zeolite and activated carbon; they suffer from low adsorption capacity,
low selective sorption and unsatisfactory regeneration capability. Nowadays innovative adsorbents are metal oxide nanoparticles, CNT, graphene and others which
have been developed to overcome these problems (Khulbe and Matsuura 2018).
Filtration process requires high pressure and more expensive rather than adsorption.
Adsorption process is a prominent, economic, convenient and simple activity. In an
experiment, zirconium nanoparticles embedded in a hollow PSF membrane
demonstrated a high adsorption potential for F removal from aqueous (He et al.
2014). Adsorption kinetics and isotherms are useful in testing adsorbent efficiency
and defluoridation ability (Smitha and Thampi 2017).
6 Fluoride Remediation Using Membrane Processes
179