Enhancement of bioleaching of a spent Ni/Mo hydroprocessing catalyst by Penicillium simplicissimum

摘要: Abstract Statistically based experimental designs were applied to screen and optimize the bioleaching of spent hydrocracking catalyst by Penicillium simplicissimum. Eleven factors examined for their significance on using a Plackett–Burman factorial design. Four significant variables (pulp density, sucrose, NaNO3, yeast extract concentrations) selected optimization studies. The combined effect these metal was studied central composite design (CCD). Second-order polynomials established identify relationship between recovery percent metals four variables. optimal values maximum as follows: pulp density (4.0%, w/v), sucrose (90 g/L), NaNO3 (2 g/L) (0.36 g/L). percentages from predicted models 97.6% Mo, 45.7% Ni, 14.3% Al. These in perfect agreement with actual values, which (98.8 ± 0.9)% (46.5 ± 0.6)% (13.7 ± 0.4)% growth kinetics fungus presence at various densities (2–11%) condition modeled modified Gompertz model. kinetic parameters system estimated MATLAB R2008a. Results showed that model fit data well. specific rate found modifying Luong inhibition gave 0.034 day−1, 3.95% w/v critical inhibitor concentration 10.9% w/v.