Research On Brown-rot Biosorbent And Its Application On Heavy Metal Remediation

A novel biosorbent was prepared from the solid-state fermentative biomass of the brown-rot Lentinus edodes. Many sophisticated techniques were used to characterize this biomaterial. The kinds of functional groups and their quantity were determined by potential titration and MATLAB simulation. The biomass was successfully applied to the bioremediation of wastewater containing heavy metals of Cr(VI), Pb2+ and Cd2+. The factors that affected the biosorption efficiency and the sorption mechanisms were studied in detail.The quality of biomaterial is the key factor that affects the sorption potential. The structure identification and the element content analysis were investigated with scanning electron microscope, plasma spectral analysis, TG analysis, 13C NMR and FTIR spectral analysis. Results showed that the brown-rot biosorbent is a kind of biomass containing plenty of mycelium and lignocellulose. The structure unit of lignin is guaiacol. The main elements are Ca, Si, K, Mg and P. Contents of heavy metals such as Cr and Pb are very low. It's a product of biomass with 22.86% of cellulose, 19.71% of hemi-cellulose and 10.24% of lignin. Functional groups such as hydroxyl, carboxyl and phosphate play important roles in biosorption.Quantitative and qualitative tests of the functional groups were carried out with methods of potential titration and MATLAB software calculation to explore the biosorption potential of the brown-rot biosorbent. Titration results showed that there are three ranges of pH that can offer H+. There are carboxyl (0.44mmol/g at pKH5.00), phosphate (1.38mmol/g at pKH7.32) and benzene hydroxyl (1.44mmol/g at pKH10.45).The biosorbent was successfully applied to sorb anion of Cr(Ⅵ). Many parameters that affected the biosorption were investigated, such as contact time, particle size, biosorbent dosage, pH of the solution, oxidation-reduction potential and the initial Cr(Ⅵ) concentration. The Fourier transform infrared spectrum and the energy-dispersive X-ray microanalyzer were employed to probe into the biosorption mechanism. During the process of biosorption, partial Cr(Ⅵ) was reduced to Cr(Ⅲ). Particle size of 450μm was ideal either considering from the preparation or from the efficiency. With the increase of biosorbent dosage, the uptake of Cr increased, but the...