425-429Applications of low cost adsorbents have been
investigated as a replacement for the current expensive methods of reducing COD
and colours from dyes/intermediate industrial wastewaters. Presently, PAC
(powdered activated charcoal) is widely used in the industries. However, it is
costly. Hence, other options have been explored which are low in cost.
Effective adsorbents have been developed from bagasse fly ash, thermal fly ash,
rice husk, jute thread and sawdust and successfully employed for the removal of
dye, ACRY red 4G from aqueous solutions. Factors influencing the adsorption
process, e.g., pH, contact time, adsorbent doses and adsorbent particle size
are investigated. The experimental data fits well to the second-order kinetic
model, which indicates that the chemical sorption is the rate-limiting step. A
continuous method for removal of ACRY red 4G from industrial wastewater without
prior treatment using all solid adsorbents such as bagasse fly ash, thermal fly
ash, rice husk, jute thread and sawdust has also been proposed. An important
aspect of the proposed method is that the removal is performed at a pH range in
which the dye ACRY red 4G undergo an adsorption process, making the method
useful for wastewater treatment