Experimental Study On Screening And Acclimation Microalgae For Removal Of Heavy Metal Ions

At present,the heavy metal pollution of water has become a worldwide environmental problem.which aroused the common concern of the whole society.The traditional processing method of heavy metals in the recovery of heavy metals is greater difficulties and easy to produce secondary pollution.New methods of heavy metal processing technical operation level is higher,such as nanotechnology.photocatalytic technology.Over the last decade,in the field of wastewater treatment.researchers have used a lot of research on the adsorption of heavy metals by non-reactive algae(algae powder),but few are studied by useing of activated algae adsorption treatment of heavy metals reports.This study used Scenedesmus Obliquus.Chlamydomonas Reinhardtii.Nannochloropsis Oculataa,Chlorella Vulgaris.Chlorel la Pyrenoidosa.Chlorella Protothecoides,Chlorella and Chlorella sp.,Dunaliella Salina for experimental study of microalgae screening and domestication in the adsorption of heavy metal arsenic ions.Finally,research and analyze the impact of acclimation before/after arsenic ions on algae lipid content.At present,there are many researches about these 9 kinds of microalgae,which are rich in raw materials and have high commercial value.The main research results are as follows:(1)In the algae screening experiment.By the growth of algae,the content of chlorophyll a and the removal rate of heavy mtals were analyzed.The results showed that arsenic ions of heavy metals had different inhibitory effects on different microalgae.The low concentration of arsenic ion promoted Scenedesmus obliquus.Chlorella synthesis of chlorophyll synthesis,and high concentration of arsenic ion can inhibit chlorophlla.The rest of the several kinds of algae chlorophyll a content increased with the arsenic ion concentration decreased.In this study,the content of arsenic ions in alginate was determined by atomic fluorescence spectrophotometer,while the adsorption rate of arsenic on arsenic was obtained.The adsorption efficiency of nine algae.(2)The acclimation experiment of algae is divided into two stages,namely.the low concentration acclimation stage when the concentration of arsenic is 1mg/l.and the high concentration acclimation stage when the concentration of arsenic is 2mg/L.After acclimation,the tolerance of the algae to the heavy metal was increased,and the damage of the heavy metal to its own was reduced to the minimum.From the contrast experiment 1,we can see that the ability of acclimated microalgae to absorb heavy metals is about 50%higher than that of the non acclimated microalgae.From the contrast experiment 2,it was found that the ability of acclimated microalgae to absorb heavy metals was about 70%higher than that of the non acclimated microalgae.(3)The content of lipid in five kinds of microalgae was different,Chlorella which the content of oil was the highest.Heavy metal arsenic ions had different inhibitory effects on the accumulation of lipid in algae.Chlorella sp.,Scenedesmus Obliquus,Chlorella Vulgaris,The amount of lipid accumulation increases with the increase of heavy metal concentration,but the increase is different.Chlorella,Nannochloropsis Oculataa,in the body of lipid accumulation with the increase in heavy metal concentration decreased.Chlorella sp.,Chlorella,Nannochloropsis Oculataa,Chlorella Vulgaris,The content of lipid is lower than that of algae before acclimation,and its accumulation of lipid and growth curve also show the opposite trend.While the acclimation of Scenedesmus obliquus is not only improved tolerance,the accumulation of lipid content also increased.In conclusion,different microalgae have different tolerance and adsorption capacity to heavy metal ions.The tolerance and removal rate of heavy metals were increased in different degree through acclimation experiment.After acclimated there are differences about lipid content in microalgae between unacclimated,the fat content of Scenedesmus obliquus reached the level of the blank control group.so acclimated can not only improve the domestication of Scenedesmus on heavy metal tolerance and adsorption ability,but also can improve the body fat accumulation.In general,this experiment provides a scientific basis and feasible technical means for the subsequent research on the treatment of heavy metal wastewater.Therefore.the use of algae in the treatment of heavy metal pollution in water environment,has a very broad prospects for development.