Isolation And Screening Of High Temperature Resistant Microalgae And Study On Removal Of Heavy Metals Mercury And Chromium

Carbon dioxide is one of the most important greenhouse gas,fossil fuel power plants accounted for about 40% of the total carbon dioxide emissions.In the combustion process,the heavy metals in coal will release and redistribution into bottom ash,fly ash and flue gas.Microalgae can directly use sunlight,carbon dioxide and other simple nutrients fast for oil accumulation.Microalgae can fix carbon dioxide from flue gas,remove heavy metal from it simultaneously.This article took the high temperature resistant as a starting point,48 strains of microalgae were screened from the soil and water samples of Yunnan,Hainan,and Xinjiang and.A series of experiments were carried out.The optimum growth temperature of strain XHS40 was studied.The optimum growth temperature was 40? among 28?,35?,40?,45? and 50?.Among nitrate nitrogen,ammonia nitrogen and organic nitrogen,the optimum nitrogen source of XHS40 is sodium nitrate.XHS40 almost cannot obligate heterotrophic,but could utilize glucose in mixed culture growth,the growth amount is 5 times of that in the autotrophic growth.Removal efficiency of chromium and mercury by 12 strains of algae screened was studied.Under the chromium concentration of 5 mg/L and 10 mg/L,the growth of most algae was inhibited obviously,and some of the algae were subjected to stress and death.Although a few microalgae were inhibited,they still could be grown.The removal rates of TY5 and XHS8 were the highest,were 29.6%,48.6% and 20.2%,21.2%,respectively under chromium concentration of 5 mg/L and 10 mg/L.Hg²⁺ toxicity is large to algae,the algae strains CJ1,CP5,HNS5,JQ6 and NT8 under the 0.1 mg/L and 1 mg/L concentrations of mercury showed a high rate of mercury ion removal,reaching about 99%,may be related to the accumulation of the large amount of biomass.