ABSTRACT
A chemo-biochemical process using Thiobacillus ferrooxidans for desulphurization of gaseous fuels and emissions containing hydrogen sulphide (H2S) has been developed. In the first stage, H2S present in fuel gas and emissions is selectively oxidized to elemental sulphur using ferric sulphate. The ferrous sulphate produced in the first stage of the process is oxidized to ferric sulphate using Thiobacillus ferrooxidans for recycle and reuse in the process. The effects of process variables, temperature, pH, total dissolved solids (TDS), elemental sulphur, ferric and magnesium ions on bio-oxidation of ferrous ions to ferric ions were investigated using flask culture experiments. The bio-oxidation of ferrous ions to ferric ions could be achieved efficiently in the temperature range of 20(+/-1)-44(+/-1) degrees C. A pH range of 1.8(+/-0.02)-2.2(+/-0.02) was optimum for the growth of culture and effective bio-oxidation of ferrous ions to ferric ions. The effect of TDS on bio-oxidation of ferrous ions indicated that a preacclimatized culture in a growth medium containing high dissolved solid was required to achieve effective bio-oxidation of ferrous ions. Elemental sulphur ranging from 1000 to 100,000 mg/l did not have any effect on efficiency of ferrous ion oxidation. The efficiency of bio-oxidation of ferrous ions to ferric ions was not affected in the presence of ferric ions up to a concentration of 500 mg/l while 3 mg/l of magnesium ion was optimal for achieving effective bio-oxidation.
Subject(s)
Ferric Compounds/metabolism , Ferrous Compounds/metabolism , Thiobacillus/metabolism , Bioreactors , Hydrogen-Ion Concentration , Magnesium Compounds/pharmacology , Oxidation-Reduction , Quality Control , Reproducibility of Results , Sensitivity and Specificity , Sulfur/pharmacology , Temperature , Thiobacillus/drug effectsABSTRACT
A patient with clinically diagnosed Stage I primary idiopathic osteoarthritis of the first metacarpal trapezium joint of the left hand received intra-articular administration of dexamethasone acetate. Compared to pretreatment T2- weighted MR images, greatly decreased MR signal intensity was observed in the affected joint space and adjacent soft tissues 2 days after dexamethasone acetate therapy. This was representative of reduced edema in the metacarpal trapezium joint and demonstrated the ability of MRI to follow pharmacological treatment for arthritis.
