Abstract:Using uranium slag as carrier, immobilization culture test of Thiobacillus ferrooxidans was carried out by adopting the method of successively reducing the inoculation rate and cyclic culture to investigate effect of PEG2000 on bacterial growth. The test results show that 90 mg/L PEG2000 has the highest effect on growth of free bacteria. Both uranium slag and K3 ring material can be used as carriers for immobilized bacteria culture. When the immobilization is completed, the average oxidation rate of its ferrous ions is stable at around 0.6 and 0.5g/(L?h) respectively. 90 mg/L PEG2000 has great promoting effects on cyclic culture and continuous culture stages. In the cyclic culture stage, time for oxidation of Fe2+ to Fe3+ can be shortened by about 1/3. In the continuous culture stage, PEG2000 can promote the oxidation rate of ferrous ions by immobilized bacteria. When influent flow rate is 0.5 L/h, the oxidation rate of ferrous ions without PEG2000 is 7.04 g/(L?h), while it is 8.18 g/(L?h) with addition of PEG2000, where the oxidation efficiency of ferrous ions rises by 16.2%.