Efficient teff-straw based biocomposites with chitosan and alginate for pyridine removal

In the present study, biocomposites prepared from agro-based biomass were investigated for pyridine adsorption from water. Biosilica, synthesised from teff straw at ashing temperature of 900 degrees C, was blended with chitosan and alginate to obtain chitosan-biosilica (ChiBS) and alginate-biosilica (AlgBS). Pyridine removal efficiency was found to be affected by the adsorption parameters namely initial pyridine concentration, contact time, pH, biocomposite dosage and temperature. The optimum conditions were contact time of 240 min and biocomposite dosage of 2 g/L for both the composites, whereas optimum pH for AlgBS and ChiBS was 8.0 and 4.0, respectively. Maximum removal efficiency for initial pyridine concentration of 50 mg/L was 96 and 90%, respectively. Adsorption equilibrium data were analysed with common adsorption isotherms and kinetics equations. Langmuir model well-fitted the equilibrium data and the pseudo-second-order fitted the pyridine adsorption rate data. Furthermore, the calculated thermodynamic parameteric values indicated physical adsorption to be dominant on both ChiBS and AlgBS, and the pyridine adsorption to be endothermic in nature.