Preliminary Study On Biosorption Of Nonliving Algae And Kelp Bio-adsorbent

In this study, kelp, gulfweed and Spirulina were used as raw materials. The three algae powder were produced after simple pretreatment and were used to the biosorption for Cu2+, Cd2+ and Pb2+ in the three heavy metal ions solution. Heavy metal biosorption was investigated by the three nonliving algae powder, including influencing factors, adsorption thermodynamics, adsorption kinetics, the preliminary study on kelp bio-adsorbent and the polysaccharide's effects on the biosorption for heavy metals by kelp and so on.Firstly, the paper had an overview of algae biosorption, including the concept of algae biosorption,adsorption characteristics, adsorption mechanism, the impact factors of adsorption; and also the introduction of research status, level and development trend was carried out at home and abroad, mainly concentrated in the biosorption capacity, the advantages of nonliving algal biosorption, adsorption thermodynamics,adsorption dynamics, pretreatment of algal bio-adsorbent, immobilization and regeneration.From the study on the impact factors of three nonliving algae biosorption, we can drawn the higher absorption rate of Cu2+, Cd2+ and Pb2+ by three algae under these conditions:the pH was between 4 and 6; the adsorption temperature was about 25℃; the initial metal ion's concentration was 100mg/L; the algae amount was between 0.5 and 1.0 g. And then we determined the effects of pH,temperature,ion initial concentration and algae amount on the algal biosorption for heavy metal ions.From the analysis of three algal biosorption thermodynamic equilibrium data and linear fitting under the Langmuir and Freundlich adsorption model, we can drawn three algae biosorption for Cu2+, Cd2+ and Pb2+ consistent with the Langmuir adsorption isotherm model, then got three algal maximum biosorption capacity for heavy metal ions.From the study of algae's adsorption kinetics, it's found out that the algal biosorption for heavy metal ions reached a balance in a short time. The result made us speculate the speed characteristics of the algal biosorption process and lays a theoretical foundation for algae's practical application.Bio-adsorbent was obtained from kelp prepared preliminary, and then we used response surface method (RSM) to determine the optimal biosorption conditions for Cd2+ that was pH 5.0, biosorption temperature 29.9℃, shock time 32 min. Under these conditions, the biosorption rate was 95.37%, and its actual yield rate was 95.37%±0.03%, RSD value was 1.07%(n=5).The changes of chemical group before and after biosorption for Cu2+, Cd2+ and Pb2+ by kelp polysaccharide that was extracted from kelp were studied, the result showed that different chemical groups played a different role in biosorption for heavy metal ions. Polysaccharide with biosorption for heavy metal ions was mainly through chemical groups and heavy metal ions complexation to achieve.