Elimination of basic blue 9 (BB-9), a cationic textile dye, by electrocoagulation coupled with biosorption exploiting pelletized natural dead leaves (PNDL) of Sapindus mukorossi, an economic alternative biosorbent, was investigated. The experimental runs were conducted in a laboratory-scale hybrid reactor loaded with Al electrodes, aeration spargers and PNDL packed twin suspended buckets. The pelletized adsorbents offer key advantages of good mechanical stability, lesser clogging risk, and easy disengagement as compared to powdered adsorbents. The parameters of current density, pH, PNDL dose, and initial dye concentration were studied for the decolorization and COD removal efficiency. The experimental results revealed that up to 99.9% decolorization and 90.01% COD removal efficiency achieved after 8 min at optimum condition of current density (j)=20.27 mA/cm2, pH = 9, PNDL dose = 6 g/L, and initial dye concentration = 50 mg/L. The BB-9 elimination followed the first-order kinetics with K1=0.318 min-1 and R2=0.997. The results revealed the potential of PNDL as a feasible biosorbent with the effective performance of the coupled process.
Keywords: Basic blue 9; FTIR; Sapindus mukorossi; biosorption; electrocoagulation.