Adsorption of Cibacron Blue Dye from Aqueous Solutions onto HCL Treated Waste Biomass

Adsorption of Cibacron blue dye from aqueous solutions onto various biomass materials was studied. Batch experiments were conducted to determine the factors affecting adsorption. Fixed bed column experiments were performed and breakthrough curves were obtained to study practical applicability. Hydrochloric acid treated coir dust, rice husk, saw dust and tea waste are capable of binding appreciable amounts of cibacron blue dye from aqueous solutions. Cibacron dye showed the highest adsorption capacity and affinity in relation to coir dust under all the experimental conditions. Coir dust and granular activated carbon showed similar adsorption capacities. Adsorption capacity was highest at the solution pH range from 2 to 3 for all the adsorbents. The adsorbent to solution ratio, and the adsorbent particle size affect the degree of dye removal. Higher adsorption capacities were observed for smaller adsorbent particles. The equilibrium data were satisfactorily fitted to Langmuir and Freundlich isotherms. Langmuir constants showed highest dye uptake of 65,14,10 and 5 mg/g for coir dust, saw dust, rice husk and tea waste respectively. Kinetic studies revealed that dye uptake was fast with 50% or more of the adsorption occurring within the first 60 to 90 min of contact time. Column operations showed lower adsorption capacities than the batch operation for all the adsorbents except tea. Breakthrough curve results fit the linear Bed Depth Service Time model. The breakthrough time depends on the solution flow rate and initial dye concentration. Amounts of dye adsorbed in the column operations were 31, 9,12, 8 mg/g for coir dust, rice husk, saw dust and tea waste respectively. 83% of colour removal and 72% of Chemical Oxygen Demand (COD) removal efficiencies were achieved using HC1 treated coir dust for the real textile wastewater samples containing a mixture of various dyes.