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Progress in Biomass and Bioenergy Production Part 6

Tham khảo tài liệu 'progress in biomass and bioenergy production part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Hexavalent Chromium Removal by a Paecilomyces sp Fungal 139 sites in the biomass and also due to the lack of binding sites for the complexation of Cr ions at higher concentration levels. At lower concentrations all metal ions present in the solution would interact with the binding sites and thus facilitated 100 adsorption. At higher concentrations more Cr ions are left unabsorbed in solution due to the saturation of binding sites Ahalya et al. 2005 . a b Fig. 5. Effect of Cr VI concentration on the removal of the metal. 1 g of fungal biomass. 100 rpm. a. - 60 C. b. - 28 C. 3.2.4 Effect of biomass concentration We studied the removal of 1000 mg L of Cr VI with various concentrations of fungal biomass at 60 C finding that to higher concentration of biomass is better the biosorption of Cr VI because the metal is removed at 70 minutes using 5.0 g of biomass Figure 6 . If we 140 Progress in Biomass and Bioenergy Production increasing the amount of biomass also increases the removal of Cr VI in solution since there are more metal biosorption sites because the amount of added biosorbent determines the number of binding sites available for metal biosorption Cervantes et al. 2001 . Similar results have been reported for biomass Mucor hiemalis and Rhizopus nigricans although the latter with 10 g of biomass Tewari et al. 2005 Bai and Abraham 2001 but are different from those reported by Zubair et al. 2008 for mandarin flax husk biomass who report an optimal concentration of biomass of 100 mg L. Fig. 6. Effect of biomass concentration on the removal of 1.0 g L of Cr VI . 100 rpm. 60 C. Finally Table 1 shows the adsorption efficiency of Cr VI by different biomass of microorganisms which shows that the biomass of Paecilomyces sp reported in this study is the most efficient in the removal of metal. 3.3 Studies with fungal alive 3.3.1 Effect of pH Figure 7 shows the effect of varying pH 4.0 5.3 and 7.0 maintained with 100 mMol L citrate-phosphate buffer. on the rate of Cr VI .