Study On The Preparation And Adsorption Performance Of Rice Straw Adsorbent

Due to the natural porous structure and unique material foundation,rice straw has been prepared to be the potential of natural adsorbent.In this thesis,rice straw were used as the raw material to the preparation for two kinds of adsorbent,and using different modification methods to develop the properties of adsorbents,then the adsorption properties of adsorbent and the physical and chemical properties have been characterized.In the part of dye-adsorption,the original unmodified adsorbent was first tested and kinetically evaluated.It was found that the unmodified straw adsorbent had a certain adsorption selectivity for different types of dyes,and it was found that the pseudo-secondary kinetic model could be used for The cationic dye adsorption process is described.the effect of carbonization modification on adsorption performance were studied by orthogonal experiments of L16(44),then,the best carbonized straw adsorbent were found out,compared to unmodified adsorbent,adsorption capacity increased by 26%,reached 32.975 mg/g.the removal of BF reached 95.45%.High select adsorption performance showed in the binary MB and MO solution,the removal rate of MB is 99.82%and the removal rate of MO is only 8.27%.According to the analysis,the main reason for the selective adsorption of cationic dyes is that the electron-negative groups on the surface make the surface of the adsorbent negatively charged with respect to the solution system and have a chemical effect on cationic dye molecules with positive charges while carrying negatively charged anionic dye molecules produce a certain degree of repulsion and thus exhibit selectivity.In the oil-adsorbed part,the performance of the original unmodified adsorbent was tested first,and it was found that the unmodified adsorbent had certain limitations on the adsorption properties of oily substances,so the acylation was used to modify the hydroxyl group of tartaric acid.Acylation with hydroxyl and amino groups in the original adsorbent resulted in an acylated modified adsorbent.After infrared spectrum analysis,the adsorbent showed obvious signs of acylation,which made the adsorbent have a certain degree of oil absorption performance increased to some extent.Dibutyl phthalate absorption capacity is 10.45 g/g,the adsorption capacity of kerosene is 10.78 g/g,the adsorption capacity of liquid paraffin was 12.78 g/g,and that of edible oil reached 11.28 g/g,respectively.And the adsorption process accords with pseudo-second-order kinetics.Thereafter,in order to increase the recoverability of the adsorbent,iron trichloride is reduced to iron tetroxide on the surface of the adsorbent by solvothermal reaction using ethylene glycol as a solvent and a reducing agent simultaneously to obtain a magnetized adsorbent,using XRD characterization can prove the effective load of triiron tetraoxide and explain the source of magnetic iron oxide.The adsorbent showed good adsorption performance in the oil-xwater adsorption system.The adsorption capacity of different oily substances was slightly decreased compared with that in the pure oil system.The reason for the analysis was that the adsorbent was pro-The deterioration of the water makes the amount of water adsorbed in the oil-water system small,so that the amount of adsorption of the oily substance does not decrease significantly,and exhibits an easily recoverable property.