Calcium alginate–bentonite/activated biochar composite beads for removal of dye and Biodegradation of dye-loaded composite after use: Synthesis, removal, mathematical modeling and biodegradation kinetics

Present study aimed to the production of calcium alginate–bentonite/activated biochar beads for implementation in methylene blue (MB) dye removal process and biodegradation study of dye-loaded composites by isolated bacteria, Lysinibacillus Sp. FTIR, TGA, SEM analysis of synthesized polymeric composite and biodegraded dye-loaded composite were performed to evaluate the surface characteristics and to identify the changes in biodegraded sample after biodegradation process. Experimental data of batch study were seemed to be extensively adjacent with the Langmuir isotherm and the maximum capacity for monolayer biosorption was 47.393 mgg−1 at 303 K and with increasing temperature, it was decreased. Additionally, the biosorption kinetics confirmed that the pseudo 2nd order model was comparatively more applicable than pseudo 1st order, Elovich diffusion and Weber–Morris intraparticle model for describing MB biosorption. Estimated magnitude of thermodynamic variables specified that the MB dye removal system was favorable at lower temperatures and endothermic process. Biodegradation study of dye-loaded composite was carried out under different operational conditions (pH, inoculum dosage, temperature, etc.) and high biodegradation efficiency was found (% weight loss >70%). Experimental data obtained from biodegradation kinetics was modeled by applying Han and Levenspiel’s model and estimated values of μmax and KS as 0.0897 h−1 and 0.102 gL−1, respectively. The calculated value of Yx/swas obtained as 67.6 g of biomass/g of dye-loaded composite.