Non-conventional Adsorbents for Dye Removal - Green Chemistry for Dyes Removal from Wastewater - page 373

Table 10.5 ( Cont .)

Adsorbent Dye q max Reference

Pumpkin seed hull Basic Blue 9 141.92 [138]

Raw date pits Basic Blue 9 80.3 [31]

Rice hull ash Direct Red 28 171 [139]

Rice husk Basic Red 2 838 [27]

Rice husk Basic Blue 9 312 [27]

Sugar beet pulp Gemazol Turquoise Blue-G 234.8 [140]

Sugar cane dust Basic Green 4 4.88 [141]

Sugar-industry-mud Basic Red 22 519 [142]

Tree fern Basic Red 13 408 [12]

Treated Parthenium Basic Blue 9 88.49 [143]

Treated sawdust Basic Green 4 74.5 [118]

Treated sawdust Basic Green 4 26.9 [118]

Vine Basic Red 22 210 [144]

Vine Basic Yellow 21 160 [144]

Wood sawdust Basic Blue 69 74.4 [145]

Wood sawdust Acid Blue 25 5.99 [145]

of its low cost and high availability, bark is very attractive as an adsor-
bent. Palma et al. [120] reported that, like sawdust, the cost of forest wastes
is only associated with the transport cost from the storing place to a site
where they will be utilized. Bark is an effective adsorbent because of its
high tannin content [121,122]. The polyhydroxy polyphenol groups of tan-
nin are thought to be the active species in the adsorption process. There
are promising perspectives for the utilization of bark as adsorbent on an
industrial scale. However, the adsorption mechanisms are not clearly iden-
tified. Tree fern, an agricultural byproduct, was also proposed to remove
pollutants from aqueous solutions [123,12]. This is a complex material
containing lignin and cellulose as major constituents, giving interesting
adsorption capacity values. The adsorption mechanism is due to chemi-
sorption (mainly ion-exchange).

10.7 Industrial Byproducts

Industrial solid wastes such as metal hydroxide sludge, fly ash and red mud
can be used as low-cost and locally available adsorbents for dye removal,