title: Rice husk ash as an effective adsorbent: evaluation of adsorptive characteristics for Indigo Carmine dye.
abstract: Present study explored the adsorptive characteristics of Indigo Carmine (IC) dye from aqueous solution onto rice husk ash (RHA). Batch experiments were carried out to determine the influence of parameters like initial pH (pH(0)), contact time (t), adsorbent dose (m) and initial concentration (C(0)) on the removal of IC. The optimum conditions were found to be: pH(0)=5.4, t=8h and m=10.0 g/l. The pseudo-second-order kinetic model represented the adsorption kinetics of IC on to RHA. Equilibrium isotherms were analyzed by Freundlich, Langmuir, Temkin and Redlich-Peterson models using a non-linear regression technique. Adsorption of IC on RHA was favorably influenced by an increase in the temperature of the operation. The positive values of the change in entropy (DeltaS(0)) and heat of adsorption (DeltaH(0)); and the negative value of change in Gibbs free energy (DeltaG(0)) indicate feasible and spontaneous adsorption of IC on to RHA.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee, India.
authors.forename: Uma R
authors.initials: UR
authors.lastname: Lakshmi
authors.forename: Vimal Chandra
authors.initials: VC
authors.lastname: Srivastava
authors.forename: Indra Deo
authors.initials: ID
authors.lastname: Mall
authors.forename: Dilip H
authors.initials: DH
authors.lastname: Lataye
mesh_terms: D000327:Adsorption; D006863:Hydrogen-Ion Concentration; D007203:Indigo Carmine / Q000378:metabolism*; D007220:Industrial Waste; D007700:Kinetics; D008855:Microscopy, Electron, Scanning; D012275:Oryza / Q000378:metabolism*; D013783:Textile Industry
chemical_list: D007220:Industrial Waste; D007203:Indigo Carmine