Studies On The Polytechnic Selection And The Properties Of The Chitosan/Anionic Surfactants Composite Hydrogel Beads

Adsorption is one of the most promising approach in the comprehensive treatment of wastewater because of good purification and low cost,in which the adsorbent is particularly critical.Due to non-toxic,good biocompatibility,biodegradability and low cost,chitosan molecules stand out in water treatment materials.In this study,different surfactants which could assemble themselves were introduced to modify chitosan.A new ideas for preparing effective adsorbent material was got based on synergies among chitosan molecules,surfactants and contaminants.In this paper,as modifiers different anionic surfactants were selected to prepare chitosan/anionic surfactant composite hydrogel.The impact of the anionic surfactant molecular structure for adsorption properties was systematically explored,the main research work was as follows:1.Preparation of composite hydrogel was optimized.By orthogonal experiment,the necessity of NaOH and ethanol for the uniform size and porous composite hydrogel was cleared.The effect of temperature and other experimental conditions for adsorption and mechanical properties was also investigated.The best experimental conditions of this study was defined:pH=5,the temperature was 30? and the content of surfactant was 0.5wt%.2 Anionic surfactant ion head group,the length and the number of hydrophobic tail chain about adsorption properties of composite hydrogel were investigated,which was associated with the relationship between the anionic surfactant molecular structure and adsorption properties of composite hydrogel.The results showed that the effect of adsorption properties of composite hydrogel was not significant when anionic head groups was changed,because the simulation of pollutants used in this experiment was anionic dyes;Increasing the length of the hydrophobic tails,the adsorption capacity of composite hydrogel would increase obviously;and the adsorption properties of AOT with single-head and bis-tails,DTM-12 with bis-heads and bis-tails were significantly increased,but the difference between them was little,which confirmed the contribution of hydrophobic interaction of the anionic surfactant modified composite hydrogel again.3.The formation and adsorption mechanism chitosan hydrogel:Surfactant was not just simply adsorbed onto the composite hydrogel,which also involved in the three-dimensional network structure of composite hydrogel;while in the adsorption process surfactant may be present in the form of single molecular or aggregates.4.Using appropriate mathematical model to obtain the interaction between Congo Red and composite hydrogel was the theory to select an appropriate absorbent.The results showed that Sips model fit well,which meant the adsorption was non-uniform the thermodynamic study;pseudo-second-order kinetic model showed the adsorption controlled by chemisorption,while the particle diffusion model showed the absorption controlled by internal diffusion in the late.