Research On The Biosorption Of Saccharomyces Cerevisiae To Chromium

At present, the action mechanism of biosorbent has not been studied in detail. Based on reviewing theories and techniques of heavy metal removal, the absorbing capability of Saccharomyces Cerevisiae(for short: SACE) to chromium is studied.The adsorption experiments of SACE (cultivation 24 h) to chromium are done. The results indicated that the pH, adsorptive time, biomass concentration and chromium concentration were crucial factors for removal of chromium. The suitable pH was 4.5~5.5, and the optimal pH was 5. The optimal adsorptive time is 30 min, and biomass concentration 40g/L(wet weight). When the concentration of chromium is 40mg/L, adsorption ratio of chromium is largest. Pretreatment can improve the biosorption capacity of SACE to chromium. The experiment of heavy metal tolerance of SACE indicated that chromium had the highest toxicity.The biosorbent of SACE-wood crumbs-activated sludge is prepared, and its biosorption capability to chromium is investigated. It was found that this biosorbent had high efficiency for removal of chromium. The optimal pH, concentration of chromium, time and biosorbent volume is obtained.SACE was immobilized on wood crumbs, and the immobilized biosorbent is packed in a glass column. The results indicated that this column had high efficiency to removing chromium. The effect of different bed depth and chromium concentration on adsorption capacity has been studied. When the initial concentration of chromium is fixed, the higher the bed depth is, the longer the breakthough time is. As the bed depth of the column is fixed, the higher the concentration is, the shorter the breskthrough time is. The adsorption process tallies with Langmuir model and Freundlich equation.The adsorption kinetics of chromium by SACE is investigated. The result shows that adsorption process obeys the pesudo second-order kinetic model.