Preparation And Basic Application Research Of Activated Carbon Based On The Lignin In The Rice Straw Pretreatment Lye

A large number of papermaking black liquor rich with lignin are burnt each year just after concentrating or simply discharged directly into rivers, which caused serious environmental pollution and waste of resources. As one of adsorbents for blood purification, activated carbon has been used extensively for the treatment of chronic renal failure. The traditional activated carbon pores are mainly microporous (diameter less than 2 nm), but molecular diameter of some toxins are greater than 2 nm, so it is limited to the traditional activated carbon’s ability to clear the toxins.In this thesis, the research object—lignin lye comes from pretreatment of rice straw with SO3 micro thermal explosion collaborative dilute alkali treatment method of the laboratory. We used concentrated precipitation method, alginate gel method and polyacrylic acid composite gel method to deal with the lignin lye to prepare bio-based activated carbon. Then Characterization and adsorption performance test are performed. Further exploration of the feasibility of lignin as a resource for medical treatment and sorbent utilization. This study attempts to compare the effect of freeze-drying and general drying on the structure and adsorption properties of prepared activated carbon in alginate gel method. Research results are as follows:1. A total of two active carbons was prepared using concentrated precipitation method to black liquor. Experimental results:the effect of adsorption of activated carbon displays phosphoric acid precipitation method is better than the direct precipitation method. The full carbon skeleton and the extent of connections shows the use of phosphoric acid can obtained a high precipitated rate of lignin from the black liquor. And the results of SEM, porosity and good adsorption of creatinine and VB12 proves optimum performance of phosphate as an activator.2. Black liquor-PAA carbon is prepared by using acrylic composite gel method. In order to investigate the interference of residual cellulose and hemicellulose in black liquor, we prepared HPMC-PAA carbon and xylan-PAA carbon. Experimental results:for the black liquor -PAA carbon, adsorption of creatinine better than the adsorption effect of VB12, and the adsorption rate was 56.89% and 40.11%, respectively. Cellulose is a certain contribution for carbon adsorption, while hemicellulose almost has no effect on the adsorption.3. A total of five active carbons were prepared using sodium alginate composite gel treatment of black liquor. Characterization display they are amorphous carbon and contain significant mesoporous. Wherein black liquor-SA composite carbon compared to sodium alginate, lyophilized charcoal compared to the dry carbon, their pore size distribution is concentrated. Five kinds of activated carbon adsorption of VB12 are better than the adsorption of creatinine, wherein the black liquor-SA composite carbon is ideal for VB12 removal can reach 91%.