| The leaching of heavy metals, such as Ni, Co or Cr was first studied with and without the presence of microorganisms. The leached metal concentrations were less than 10 mg/L. The effects of temperature and solution pH on coal biodesulfurization were also studied. With T. ferrooxidans, the optimal pH was around 2.5; while with S. brierleyi, an increase of temperature from 60 to 70;Coal desulfurization was first studied with 5% slurry (pH = 2.5) by mesophilic bacteria T. ferrooxidans and T. thiooxidans. at 30;The growth kinetics of the mesophiles, thermophile and heterotrophic Pseudomonas putida were also studied. Monod equation was used to model the growth of both the mesophilic and thermophilic microorganisms while a modification with an inhibitory effect of intermediates was included to describe the growth and substrate utilization during the growth of P. putida on benzoate.;The kinetics of coal desulfurization of both mesophiles was described by Monod model while a Monod-like, no growth or non-growth related model was employed to illustrate the biodesulfurization of S. brierleyi. The values of parameters of these models were estimated by non-linear regression method. Perturbation analyses of parameters of these models were also performed. |
