Sulfur Dioxide Removal From Industrial Gas By Microbial Method

Nove Fe3O4/poly (St-MA) magnetic porous beads (MPBs) were fabricated by a seed swelling process using magnetite particles as seeds. MPB was characterized with high spherity, strong adsorption, low density, high specific surface area, large porous degree, large porous volume and narrow porous diameter distribution. The average porous diameter was within the range of bacteria diameter. Acid anhydride groups were found on the surface and in the pores, so MPB had better hydrophilicity and biocompatibility to make the large collection of microorganism, fast growth and easy mass transferring and exchange. It is a kind good carrier to immobilize enzyme and microorganism. Magnetic properties of the MPBs were obtained by electron spin resonance (ESR) and vibrating-sample magnetometer (VSM). All the observations indicated that the beads were ferromagnetic. The g value of MPB is 2.013 without distinctive residual magnetism and coercive force. 3300 G magnetic field can cause 1g MPB dipolar movement. In this study, MPB immobilized with SRB and CSB was filled in the magnetic stabilized fluidized bed to realize the control of the fluidized bed through magnetic stabilization function.According to the sulphur metabdism mechanism of SRB and CSB, the flue gas biodesulplurization system was designed out. Complete treatment of SO₂ from flue gas in a four-stage process consisting of a bio-trickling filter, two magnetically stabilized fluidized bed reactor (MSFB) and sulfur separator was investigated. The bio-trickling filter was able to adsorb 95% of SO₂ at the gas/liquid rate of 216 for a concentration of 3000 mg/m3 and the adsorbed SO₂ was converted to sulfite and sulfate. The effluent of the bio-trickling filter was further processed biologically in the anaerobic MSFB (anMSFB) for the reduction of sulfite to sulfide. Subsequently, the resulting sulfide was oxidized in the aerobic MSFB (aMSFB) to elemental sulfur. The anMSFB and aMSFB were both carried out in the"flow–first"mode at a current of 5A. The biofilm formation process in the biodesulfurization system was studied during the start-up by microscope, scanning electromicroscope and TGGE-PCR molecular biology. Microscope and scanning electro-scope observation indicated that the biofilm in anMSFB and aMSFB was mainly made of coccal bacteria, short rod bacteria, long rod bacteria and trichobacteria. The influential factors, microorganism...