Adsorption Of Pb²⁺ By Cellulose Composites

The paper studies the adsorption properties of cellulose-based adsorbent for thewater of Pb²⁺.On the one hand, the cellulose beads were obtained by instilled（[BMIM]Cl）-dissolved cellulose into distilled water and efficient adsorbent for heavymetal ions-polyamine porous cellulose microspheres were prepared by themodification of the physical structure and chemical groups. On the other hand,another cellulose-based sorbent-ester corn cob was obtained from the splintereddirectly corncob as raw materials by the rapid etherification reaction, which offers anew method for the application of cellulose resources with high value. Various factorssuch as pH, adsorption time and initial concentration of Pb²⁺had considerable effectson Pb²⁺adsorption capacity of cellulose beads and corncob. The structure andmorphology of the cellulose beads and corncob were characterized by FTIR, XRDand SEM analysis. The the impact of each modification step was analyzed to explorethe impact of the change of the structure and morphology on the adsorption capacity,which can provide new ideas for the efficient modification of the follow-up ofcellulose-based adsorbent. the conclusions of this paper can be drawn as follows:Ionic Liquids regenerated cellulose microspheres Ⅰand Ⅱ:The cellulosebeads were obtained by instilled （[BMIM]Cl）-dissolved cellulose into distilled water.Porous pure cellulose microspheres Ⅰwith uniform diameter distribution andstarch/cellulose blend microspheres II （starch hydrolysis） were prepared, themoisture content, porosity and average diameter were89.1and90.0;0.925and0.932;4.28mm and4.23mm.Adsorption properties of the multi-amine cellulose microspheres Ⅰ: Pb²⁺adsorption capacity of Regenerated cellulose microspheres I Modified by ethyleneand polyamines were examined. The pH, adsorption time and initial Pb²⁺concentration have a greater impact on the adsorption capacity of the polyaminescellulose microspheres; when the initial Pb²⁺concentration was6mmol/L at pH=5.0,the equilibrium adsorption capacity of Pb²⁺by polyamine cellulose microspheres wasup to96.4mg/L; at30℃, The adsorption process could be best characterized by apseudo-second-order mode, and the adsorption isotherms were agreed well with theLangmuir mode, indicating that the chemical adsorption step was the rate-limited stage and this process is spontaneous. Moreover, the maximum adsorption amount ofPb²⁺was99.5mg/g, and, the adsorption capacity still maintained to78.64%relativeto the initial one after five times adsorption-desorption process.The adsorption properties of multi-amine cellulose microspheres II: Pb²⁺adsorption capacity of Starch/cellulose blend microspheres II after hydrolysis byamylase and modified by ethylene and polyamines were investigated. Starch blendand the hydrolysis process of cellulose microsphere make the porosity and internaland external aperture increase. At30℃, the maximum adsorption amount of Pb²⁺was increased from99.5mg/g to133.2mg/g. The adsorption process could be bestcharacterized by a pseudo-second-order mode, and the adsorption isotherms wereagreed well with the Langmuir mode and this process is spontaneous. The adsorptioncapacity still maintained to79.23%,relative to the initial one after five timesadsorption-desorption process.Esterification of corn core: Pb²⁺adsorption capacity of crushed corn cob afterrapid esterification reaction. Various factors such as pH, adsorption time and initialconcentration of Pb²⁺had considerable effects on Pb²⁺adsorption capacity of corncob.At30℃, the maximum adsorption amount of Pb²⁺was increased to52.47mg/g. Theadsorption process could be best characterized by a pseudo-second-order mode, andthe adsorption isotherms were agreed well with the Langmuir mode and this processis spontaneous.