Determination of Kinetic Parameters in the Biosorptionof Cr (VI) on Immobilized Bacillus cereus M116in a Continuous Packed Bed Column Reactor

摘要

Due to technological advancement, environment suffers from untreated toxicheavy metal bearing effluent coming from different industries. Chromium (VI) is one ofthose heavy metals having adverse impact on ecological balance, human, and plant healthbecause of its carcinogenic properties. Biosorption is presented as an alternative totraditional technologies which are costly and inefficient for treatment of industrial wastescontaining low amount of heavy metals. In this study, bioremediation of Cr (VI) ions byimmobilized Bacillus cereus M' 16was investigated in a laboratory scale packed bed up-flow column reactor. The effect of important parameters, such as the inlet flow rate, influentconcentration, and effective bed height, has been studied. External mass transfer, surfaceadsorption, and intrabead mass transfer were also studied to conclude the rate limiting stepfor removal of Cr (VI) and to determine the process parameters which are important forbiosorption optimization. The external mass transfer coefficient was calculated at differentflow rates (6.51x 10~(-2)to 7.58 x 10~(-cm/min). Using the model, surface adsorption rateconstant (kad) and the intrabead mass transfer coefficient (10 were predicted as 0.0267 x10-3 and 0.7465 x10~(-3)l/g/min, respectively. Both are much lower than the external masstransfer coefficient (k_c). The surface adsorption phenomenon is acting as the rate-limitingstep due to its high resistance for removal of Cr (VI).