The Optimization Of Cr(?) Biosorption Conditions By Chlorella Vulgaris And The Physio-biochem Response Of Chlorella Vulgaris To Cr(?) Stress

In recent years,there are a lot of heavy metal pollution incidents in our country.Those events were not only a serious impact on our life,but also resulted in significant economic losses.We must attach great importance to the question of heavy metal pollution and find effective ways to control heavy metal pollution.Using algae as a biosorbent on the treatment of heavy metal wastewater has great potential in the present methods.In this study,Chlorella vulgaris was used to investigate the effects of environmental factors such as pH,temperature on the biosorption of chromium???by C.vulgaris and physiological,biochemical characteristics of C.vulgaris after chromium???stress.The purposes of this study were to determine the optimal condition of biosorption of chromium???by C.vulgaris,explore the influence of chromium???stress on C.vulgaris and the response mechanism of C.vulgaris exposed to chromium???.The key findings are as follows:?1?To improve the Cr³⁺biosorption efficiency and biomass of C.vulgaris,the optimal combination is 31?in temperature and 5 in pH.At this condition,when the concentration of Cr³⁺was 3 mg/L,the biomass and biosorption efficiency of C.vulgaris were relatively high,respectively,0.72 g/L and 82.1%.?2?When the concentration of Cr³⁺was lower than 3 mg/L,Cr³⁺could promote the growth of C.vulgaris,while it would inhibit the growth of C.vulgaris when the concentration of it was higher than 3 mg/L.?3?Cr³⁺significantly increased the concentrations of total chlorophyll,carotenoid and the contents of protein,soluble sugar of C.vulgaris at the Cr³⁺concentration of 3mg/L.Among the range of concentration selected,they increased first and then decreased with the increasing concentration of Cr³⁺.?4?Among the range of concentration selected,the content of MDA in C.vulgaris increased with the increasing concentration of Cr³⁺.?5?Among the range of concentration selected,with the increasing concentration of Cr³⁺,the activity of SOD and content of proline in C.vulgaris increased gradually,while the content of proline increased significantly.