adsorption on the active surface of the media. The removal of As from natural water
by adsorption method, and the use of granular ferric hydroxide as an adsorbent are
highly effective (Mohan and Pittman 2007). Sono 3-Kolshi filter containing sand,
brick chips, zero valent iron fillings, and wood coke are also good example of
adsorbent used for As removal.
5.4.3 Membrane Processes
Membrane processes for As removal include nano-filtration, ultra-filtration, electrodialysis, and reverse osmosis which use synthetic membranes for removal of many
contaminants including As. The dramatic improvement in membrane technologies
for water purification and treatment is due to its low energy cost, ease of scaling up,
and high efficiency and stability over the past two decades. Membranes remove As
through electric repulsion, filtration, and adsorption of arsenic-bearing compounds.
Several cost-effective As removal filters have been developed by different national
research organizations of India. The Indian Institute of Technology, Bombay (IITB)
has developed a cost-effective, robust, iron-based As removal filter. Defence
Research and Development Organization (DRDO) developed an As removal filter
based on co-precipitation and adsorption. The Indian Institute of Technology,
Kharagpur has developed a laterite-based As filter which is eco-friendly and ultralow cost-effective. Agharkar Research Institute (ARI), Pune has developed a plant
for As treatment. These As removal tools are efficient for As removal in lab
conditions as well as in As-contaminated fields (Mishra et al. 2016). The use of
membranes for the removal of contaminant like As has attracted attention as this
possesses potential to be easily applicable even at personal home level. The membranes can also utilize biological functional components like specific transporter
proteins to enhance the rate and efficiency of filtration (Werber et al. 2016; Ling
et al. 2017).
5.4.4 Phytoremediation
The biological methods that include phytoremediation and bioremediation are
ecofriendly and cost-effective for protecting human health and environment from
toxic metal contamination. Phytoremediation involves the use of green plants for
removal of contaminants. In phytoremediation, plant removes heavy metals by using
one of these mechanisms, such as phytodegradation, phytoextraction, rhizofiltration,
phytostabilization, and phytovolatilization (Kumar et al. 2020). There is an immense
natural diversity in the As response among different plant species. Few plant species
have a great potential of phytoremediation strategies as they are enriched with
mechanisms for As detoxification and hyperaccumulation. A plant species is recognized as As hyperaccumulator if it accumulates more than 1000 μg/g As. Several
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S. Awasthi et al.
by adsorption method, and the use of granular ferric hydroxide as an adsorbent are
highly effective (Mohan and Pittman 2007). Sono 3-Kolshi filter containing sand,
brick chips, zero valent iron fillings, and wood coke are also good example of
adsorbent used for As removal.
5.4.3 Membrane Processes
Membrane processes for As removal include nano-filtration, ultra-filtration, electrodialysis, and reverse osmosis which use synthetic membranes for removal of many
contaminants including As. The dramatic improvement in membrane technologies
for water purification and treatment is due to its low energy cost, ease of scaling up,
and high efficiency and stability over the past two decades. Membranes remove As
through electric repulsion, filtration, and adsorption of arsenic-bearing compounds.
Several cost-effective As removal filters have been developed by different national
research organizations of India. The Indian Institute of Technology, Bombay (IITB)
has developed a cost-effective, robust, iron-based As removal filter. Defence
Research and Development Organization (DRDO) developed an As removal filter
based on co-precipitation and adsorption. The Indian Institute of Technology,
Kharagpur has developed a laterite-based As filter which is eco-friendly and ultralow cost-effective. Agharkar Research Institute (ARI), Pune has developed a plant
for As treatment. These As removal tools are efficient for As removal in lab
conditions as well as in As-contaminated fields (Mishra et al. 2016). The use of
membranes for the removal of contaminant like As has attracted attention as this
possesses potential to be easily applicable even at personal home level. The membranes can also utilize biological functional components like specific transporter
proteins to enhance the rate and efficiency of filtration (Werber et al. 2016; Ling
et al. 2017).
5.4.4 Phytoremediation
The biological methods that include phytoremediation and bioremediation are
ecofriendly and cost-effective for protecting human health and environment from
toxic metal contamination. Phytoremediation involves the use of green plants for
removal of contaminants. In phytoremediation, plant removes heavy metals by using
one of these mechanisms, such as phytodegradation, phytoextraction, rhizofiltration,
phytostabilization, and phytovolatilization (Kumar et al. 2020). There is an immense
natural diversity in the As response among different plant species. Few plant species
have a great potential of phytoremediation strategies as they are enriched with
mechanisms for As detoxification and hyperaccumulation. A plant species is recognized as As hyperaccumulator if it accumulates more than 1000 μg/g As. Several
114
S. Awasthi et al.