| As a kind of functional materials with three-dimensional network structure, starched resin have promising application in many fields, such as agricultural water conservation, hygienic products, wastewater treatment and so on. In the present studies, the swelling rate of super absorbent resin of starch could be thousands. Due to its slow liquid-absorbing rate, super absorbent resin of starch have limited its application in hygienic products. As a kind of environmental friendly adsorbent materials, starched porous resin has application value on dye removal of the industrial wastewater, but the low dye adsorption capacity limits its application in wastewater treatment. To solve above two problems, using the mechanical activated cassava starch as raw material, starched porous resin was prepared by the foam pore-forming technology. The specific research content is as follows:(1) The effects of the dosage and type of pore-forming agent, the mass ratio of AA to starch, the dosage of crosslinking agent and initiator on the swelling rate and liquid-absorbing rate of the porous resin were investigated. The results showed that when the synthesis conditions are 21.45% of pore-foaming agent(NaHCO3),10:1 of mass ratio of AA to starch,0.05% of crosslinking agent, 3% of initiator,1.3 mol·L-1 of accelerator TEMED and 75% of the neutralization degree of acrylic acid, the saturation absorption rate of deionized water and saline absorption rate are 875 g·g-1 and 95 g·g-1, respectively, and the times of which only need 90 s and 100 s. And the saturation absorption rate and time of deionized water of the starched porous resin which without pore-forming agent were 30 min and 900 g·g-1. The porous resin which was prepared by the foam pore-forming technology have no difference on absorption rate of deionized water, compared with which without pore-forming agent, but the speed have been approved significantly. Environmental temperature, pH value and external forces have great influence on the absorption properties of porous resin. And different temperatures and centrifugal forces will affect the water conservation property of porous resin.(2) The morphology, structure and thermal properties of the porous resin was characterized by scanning electron microscopy, infrared spectrometer, X-ray diffraction and DSC-TG thermal analyzer. The results of scanning electron microscopy showed that starch/acrylic acid grafted copolymerization resin is porous morphology, and which without pore-forming agent is none pore morphology. The results of infrared spectrum and X-ray diffraction showed that starch and acrylic acid were successfully grafted and copolymerized. The results of DSC-TG thermal analysis showed that the porous resin in this work have no obvious differences with traditional starched resin on thermal property.(3) The absorption property for methylene blue of starched porous resin was investigated. The effects of the dosage and type of pore-forming agent, the mass ratio of AA to starch, the dosage of crosslinking agent and initiator on the absorption capacity of porous resin were also investigated. Moreover, we also study the isothermal model and kinetics of the adsorption of porous resin for MB. The results shown that when the synthesis conditions are 21.45% of pore-foaming agent(NaHCO3),10:1 of mass ratio of AA to starch,4% of crosslinking agent, the adsorption capacity of porous resin for methylene blue is 1432 mg·g-1. The process of isothermal adsorption of porous resin for MB accorded with the Sips adsorption and the adsorption kinetics was stick to the pseudo first order kinetics, mechanism of which was similar to the mechanism of solid-liquid adsorption. The absorption capacity of the same kind of natural polymer resin for MB in the references is in the range of 50 mg·g-1～750 mg·g-1. It could be seen that the absorption of starch/acrylic acid grafted copolymerization resin for MB which was prepared by the pore-forming technology have been improved significantly. |
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