Solar red BA (SR-BA) and solar brittle blue A (SBB-A) direct dyes adsorption using Eucalyptus
angophoroides bark (EAB) biomass was studied. The effect of process variables i.e., pH, contact time,
particle size, temperature, initial dyes concentration, adsorbent dose and NaCl addition were
investigated. The adsorption isotherms (Langmuir, Freundlich and Temkin), kinetics models (pseudofirst
and pseudo-second-order) and thermodynamics parameters (DH, DS and DG) were employed to
evaluate the adsorption mechanism. Thermodynamic studies indicated the spontaneous and exothermic
adsorption process of both dyes onto EAB. Maximum adsorptions of SBB-A and RR-BA onto EAB were
49 mg/g and (43.5 mg/g), respectively at 2 pH, 0.25 mm particle size, 303 K, 0.1 g adsorbent dose, 0.05 M
NaCl, 25 mg/L dyes initial concentration and contact time 180 min (SBB-A) and 240 min (RR-BA). The SEM
and FTIR studies of dye loaded and unloaded biomass were performed in order to check the surface
morphology and functional group involved in dye adsorption. The optimized conditions were applied for
the adsorption of dyes from textile wastewater and up to 65.4%
3.20 dye removal was achieved. Results
indicated that the EAB could be an efficient and low cost adsorbent for the adsorption of dyes form textile
effluents.