Abstract
This present study evaluates the adsorptive effectiveness of mixed pine cone biomass and kaolin clay adsorbents in removing methylene blue (MB) dye from its aqueous solution using a packed-bed column adsorption experiment. A series of column experiments were performed to determine the breakthrough curves (BTCs) by varying bed height, inlet feed flow rate and initial MB dye inlet concentration and various characteristic parameters such as % removal of dye, initial breakthrough time, used bed length and unused bed length, mass transfer zone (MTZ) and dye adsorption density (q(total)) were determined here. The adsorption of MB dye was found most favourable under low feed flow rate, high adsorbent bed height and high initial MB dye concentrations. Four kinetic column models, namely Thomas, Yoon-Nelson, Clarkand Bed Depth Service Time (BDST) were fitted against the experimental data to predict the column breakthrough curves (BTC) behaviour under different operational conditions. All models were found suitable in describing the dynamic behaviour of the column. The various adsorptive kinetic parameters such as rate constant, the adsorption capacity for Thomas model, the time for 50% breakthrough in Yoon-Nelson model, Clark constants, the service time for BDST model and unused bed are determined and critically analysed which are useful for designing the large-scale column operation. This continuous column study revealed the strong ability of mixed pine cone biomass and kaolin clay packed bed adsorbents to remove the dye and other pollutants and may be recognised as an alternative sustainable solution for dye-bearing wastewater treatment in industrial scale.