Batch and continuous closed circuit semi-fluidized bed operation: Removal of MB dye using sugarcane bagasse biochar and alginate composite adsorbents

Abstract

The feasibility of a novel composite adsorbent beads prepared from Sugarcane bagasse biochar (SB) entrapped in Calcium-alginate (CASB) to eliminate Methylene Blue dye (MB) from aqueous solution was investigated by batch and close circuit semifluidized bed column studies. Sugarcane bio-char was synthesized from sugarcane bagasse through slow pyrolysis at 500 °C in an oxygen-free environment. Both CASB and SB biochar were characterized using FTIR and FESEM. BET and XRD analysis to understand the surface properties. Batch adsorption kinetics were performed to identify and optimize the various physicochemical process parameters such as solution pH, initial dye concentration, temperature, and adsorbent dose and its effects on adsorption mechanism. In a closed-circuit bed experiment, the effect of initial MB dye concentration, height of the initial bed and liquid feed flow rate on MB removal was studied. The maximum bed capacity of 30.13 mg/g was found at 40 mg/L of initial solute concentration, 10 cm bed height, and 2.5 LPM feed flow rate with 95.47 % removal of MB. The results suggested the sustainable application of CASB biochar as an effective adsorbent and semi-fluidized bed operation as an improved continuous effluent treatment operation alternative to packed bed and fluidized bed operation.