260
T. Sahoo et al.
11.4.3 Metal–Organic Framework for Heavy Metal Removal
from Water
Rapid pollution of ground and surface water due to heavy metal contamination is a
crucial issue worldwide. It not only affects the purity of the environment but also
have adverse impact on human health. Excessive abundance of these harmful metals
causes the risk to human life by initiating much dreadful disease like cancer and
also affects other species by accumulating in the food chain. It is very essential to
eliminate these elements from surrounding especially from water bodies up to permissible level. Metal–organic frameworks or MOFs are defined as category of porous
adsorbent material made up of metal clusters and organic linkers. These frameworks
are connected in 3D lattices. Metal–organic frameworks exhibit a number of benefits
in the field of adsorption. The unique characteristics of porous structure and high
surface area enabling it to be applied for many fields like drug delivery, catalysis, gas
storage and separation (Kuppler et al. 2009). The property of porosity and large surface area supports the contaminants in accessing the adsorption site and gets diffused
into the framework. The crystallinity aids MOF with highly ordered pores, and shape
and size of these pores can be controlled by selecting suitable ligands and metal ions
(Yaghi et al. 2003). MOFs can be effectively used in the removal of pollutants from
water, and this is a very popular area of research nowadays. Table 11.1 displays some
important MOFs and their role in heavy metal removal.
11.4.4 Removal of Nanoparticles After Water Treatment
Using nanoparticles for various environmental applications causes the release of these
particles and accumulation in the environment. In order to assess the amount of risk
that can be incurred on the environment, knowledge regarding its persistence, toxicity, bioavailability and mobility is required. The rapid utilization of nanoparticles for
various industrial applications and the purification of water especially drinking water
arise a threat that these nanomaterial will remain in the environment and will cause
damage and hence needs to be eliminated by suitable pathways. Conventional pathways for the elimination of suspended matter in the wastewater popularly include
filtration and sedimentation. But, the size of the nanoparticles is very small, and
hence, the sedimentation technique is not suitable for removal unless they aggregate and form larger size. Techniques like flocculation can be also not suitable for
eliminating nanoparticles from the water, and hence, some novel process is required.
Techniques like reverse osmosis and nanofiltration which are also applied for removal
of pathogenic substances from wastewater can be also applied for removing nanoparticles. These hindrances are based on the fact that these nanomaterials are mobile
in the presence of porous medium due to their minute size, thereby they get dispersed over a large area and remain persistent in the environment for a longer time.
T. Sahoo et al.
11.4.3 Metal–Organic Framework for Heavy Metal Removal
from Water
Rapid pollution of ground and surface water due to heavy metal contamination is a
crucial issue worldwide. It not only affects the purity of the environment but also
have adverse impact on human health. Excessive abundance of these harmful metals
causes the risk to human life by initiating much dreadful disease like cancer and
also affects other species by accumulating in the food chain. It is very essential to
eliminate these elements from surrounding especially from water bodies up to permissible level. Metal–organic frameworks or MOFs are defined as category of porous
adsorbent material made up of metal clusters and organic linkers. These frameworks
are connected in 3D lattices. Metal–organic frameworks exhibit a number of benefits
in the field of adsorption. The unique characteristics of porous structure and high
surface area enabling it to be applied for many fields like drug delivery, catalysis, gas
storage and separation (Kuppler et al. 2009). The property of porosity and large surface area supports the contaminants in accessing the adsorption site and gets diffused
into the framework. The crystallinity aids MOF with highly ordered pores, and shape
and size of these pores can be controlled by selecting suitable ligands and metal ions
(Yaghi et al. 2003). MOFs can be effectively used in the removal of pollutants from
water, and this is a very popular area of research nowadays. Table 11.1 displays some
important MOFs and their role in heavy metal removal.
11.4.4 Removal of Nanoparticles After Water Treatment
Using nanoparticles for various environmental applications causes the release of these
particles and accumulation in the environment. In order to assess the amount of risk
that can be incurred on the environment, knowledge regarding its persistence, toxicity, bioavailability and mobility is required. The rapid utilization of nanoparticles for
various industrial applications and the purification of water especially drinking water
arise a threat that these nanomaterial will remain in the environment and will cause
damage and hence needs to be eliminated by suitable pathways. Conventional pathways for the elimination of suspended matter in the wastewater popularly include
filtration and sedimentation. But, the size of the nanoparticles is very small, and
hence, the sedimentation technique is not suitable for removal unless they aggregate and form larger size. Techniques like flocculation can be also not suitable for
eliminating nanoparticles from the water, and hence, some novel process is required.
Techniques like reverse osmosis and nanofiltration which are also applied for removal
of pathogenic substances from wastewater can be also applied for removing nanoparticles. These hindrances are based on the fact that these nanomaterials are mobile
in the presence of porous medium due to their minute size, thereby they get dispersed over a large area and remain persistent in the environment for a longer time.