380
aqueous solution, sugarcane bagasse also can be used as successful adsorbent
(Demirbas 2009). Waste from several industries such as sludge and slag from steel
industry (inorganic), blast furnace dust, and a carbonaceous waste from a fertilizer
industry (organic) can be also used as adsorbents in separating dye (Jain et al. 2003).
However, new materials which are easily available, more economical and highly
efficient are still under the development as the capacity of the above materials are
not very large (Saad et al. 2010; Jain et al. 2003). The main objective of this book
chapter is to cover the recent developments of various kind of non-conventional,
sustainable low-cost adsorbent with their applications and also analyze the maximum adsorption capacity at various operation conditions.
15.2 Dyes
Colorant is the highly colored substance that is used for imparting color on various
substrates. Colorants are subdivided into two groups such as dyes and pigments.
Dyes are the colored substances having an affinity to give a permanent color when
applied to fibers, made from more than one compounds obtained from distillation of
coal tar (Rai et al. 2005). Dyes are soluble in a medium and mainly used as aqueous
solution, but it requires a mordant for improving the fastness of dye on substrates.
On the other hand, pigments are insoluble in the medium, and it has no affinity to
the substrates (Moore et al. 2011). It has been found that India and the Middle East
countries were carried out over 5000 year in variety of industries that consume huge
amount of dyes (Parsa and Negahdar 2012; Sharma and Kaur 2018).
15.2.1 Definition of Dyes
Dyes are basically inorganic or organic compounds having a synthetic and compound unsaturated aromatic structures of molecules with accomplishing characteristics like color, intensity, fastness, and completely soluble in aqueous media (Gong
et al. 2005; Sharma and Kaur 2018). Due to their chemical composition, synthetic
dyes have the resistance for fading up in water, light, and variety of chemicals and
the acidic properties build them more strong and stable to biodegrade when it mixed
with water (Abid et al. 2012; Wang and Li 2007).
At present, more than 10,000 dyes are available commercially. Dyes comprise
with two basic components such as, chromophore and auxochrome. Chromophores,
i.e., electrons acceptor in dye molecules is basically an electron withdrawing group,
responsible for creating color due to its capability for absorbing light near ultraviolet
region. The chromogene is an aromatic compound containing benzene, anthracene,
or naphthalene rings with binding chromophores containing double conjugated links
with delocalized electrons that form a conjugated system. The most important groups
of chromophores are the ethylene, azo, carbonyl, methine, carbon coupled with
M. Sardar et al.
aqueous solution, sugarcane bagasse also can be used as successful adsorbent
(Demirbas 2009). Waste from several industries such as sludge and slag from steel
industry (inorganic), blast furnace dust, and a carbonaceous waste from a fertilizer
industry (organic) can be also used as adsorbents in separating dye (Jain et al. 2003).
However, new materials which are easily available, more economical and highly
efficient are still under the development as the capacity of the above materials are
not very large (Saad et al. 2010; Jain et al. 2003). The main objective of this book
chapter is to cover the recent developments of various kind of non-conventional,
sustainable low-cost adsorbent with their applications and also analyze the maximum adsorption capacity at various operation conditions.
15.2 Dyes
Colorant is the highly colored substance that is used for imparting color on various
substrates. Colorants are subdivided into two groups such as dyes and pigments.
Dyes are the colored substances having an affinity to give a permanent color when
applied to fibers, made from more than one compounds obtained from distillation of
coal tar (Rai et al. 2005). Dyes are soluble in a medium and mainly used as aqueous
solution, but it requires a mordant for improving the fastness of dye on substrates.
On the other hand, pigments are insoluble in the medium, and it has no affinity to
the substrates (Moore et al. 2011). It has been found that India and the Middle East
countries were carried out over 5000 year in variety of industries that consume huge
amount of dyes (Parsa and Negahdar 2012; Sharma and Kaur 2018).
15.2.1 Definition of Dyes
Dyes are basically inorganic or organic compounds having a synthetic and compound unsaturated aromatic structures of molecules with accomplishing characteristics like color, intensity, fastness, and completely soluble in aqueous media (Gong
et al. 2005; Sharma and Kaur 2018). Due to their chemical composition, synthetic
dyes have the resistance for fading up in water, light, and variety of chemicals and
the acidic properties build them more strong and stable to biodegrade when it mixed
with water (Abid et al. 2012; Wang and Li 2007).
At present, more than 10,000 dyes are available commercially. Dyes comprise
with two basic components such as, chromophore and auxochrome. Chromophores,
i.e., electrons acceptor in dye molecules is basically an electron withdrawing group,
responsible for creating color due to its capability for absorbing light near ultraviolet
region. The chromogene is an aromatic compound containing benzene, anthracene,
or naphthalene rings with binding chromophores containing double conjugated links
with delocalized electrons that form a conjugated system. The most important groups
of chromophores are the ethylene, azo, carbonyl, methine, carbon coupled with
M. Sardar et al.