Adsorption Mechanism and Process Optimization of Inonotus obliquus Polysaccharide Pigment by Macroporous Resin

To explore the kinetic, thermodynamic characteristics and optimal conditions of the removal the inner pigment of the Inonotus obliquus polysaccharide by macroporous resin. In this study, the total Inonotus obliquus polysaccharide was prepared by water extraction and alcohol precipitation, Sevag method for protein removal, and dialysis. A preliminary screening of 17 macroporous resins were carried out by static adsorption method. And the score was calculated by pigment removal rate and polysaccharide retention rate. The parameters affecting the pigment inner Inonotus obliquus polysaccharide removal process, such as flow rate, adsorption time, ratio of diameter to height and sample concentration were studied and optimized along with evaluation of kinetic and thermodynamic parameters. The results showed that HPD-500 was the best suitable one among the 17 kinds of macroporous resins. The adsorption process followed pseudo-second-order model, which was affected by both intra particle diffusion and liquid film diffusion. The thermodynamic results showed that the adsorption was more in line with the Freundlich model, which was a multi-molecular layer adsorption. The rmodynamic parameters were also evaluated, enthalpy>0, Gibbs free energy<0, entropy>0, which showed that extraction was an endothermic, spontaneous and entropy increase reaction. Under the optimal conditions for removed pigment with elution ratio of diameter to height of 1:10, adsorption time of 1h, sample weight of 10 mg and flow rate of 1.5 mL/min, the pigment removal rate of Inonotus obliquus polysaccharide was 83.15%, the retention rate was 78.89%, with the purity promoted from 20.40% to 56.52%. The HPD-500 macroporous resin had the ability to remove the pigment and improve the purity of Inonotus obliquus polysaccharide. This article provided a theoretical and experimental basis for the efficient utilization of Inonotus obliquus resources.