| Natural polymer materials such as cellulose and alginic acid have the characteristics of good biocompatibility,strong biodegradability,low acquisition cost and good regenerability,showing great prospects in the field of adsorption.In this context,sodium alginate/carboxymethyl cellulose aerogel and calcium alginate/carboxymethyl cellulose spherical aerogel are prepared by crosslinking,blending,freeze drying method and floating droplet method.The optimal preparation conditions for of these two materials as adsorbents for the removal of methylene blue from aqueous solutions were investigated.The chemical structures and surface morphology of the adsorbents were characterized by scanning electron microscopy,infrared spectroscopy,thermogravimetric analysis,specific surface area and pore size distribution.The effects of different temperature,adsorbent addition amount,initial pH value and adsorption contact time on the adsorption properties of methylene blue for these two adsorbents were studied.The adsorption data of the two adsorbents were fitted and analyzed by adsorption isotherm,adsorption kinetic equation and adsorption thermodynamic equation.The specific adsorption process of methylene blue in aqueous solution was studied.The recycling performance of calcium alginate/ carboxymethyl cellulose Spherical aerogel for adsorption of methylene blue and the removal of different types of dyes were investigated.The experimental results show that The materials have good removal effect on methylene blue in aqueous solution.Both the Langmuir model and the Friedrich model can well describe the adsorption equilibrium parameters of the two adsorbents.The theoretical maximum adsorption capacities of these two materials for methylene blue were calculated by the Langmuir model to be 3160.49 mg/g and 2199.48 mg/g,respectively.The adsorption of methylene blue by both materials is in accordance with the pseudo-second-order kinetics model,and the adsorption of methylene blue is chemical adsorption.The theoretical adsorption capacity of sodium alginate/carboxymethyl cellulose aerogel for methylene blue is high,indicating that sodium alginate/carboxymethyl cellulose aerogel is a highly efficient adsorbent material.The calcium alginate/carboxymethyl cellulose aerogel sphere has a three-dimensional porous network structure inside,and after 5 adsorption-desorption cycles,the relative adsorption amount of methylene blue is over 96%,indicating that the calcium alginate/carboxymethyl cellulose aerogel sphere is an adsorbent material with excellent cycle performance. |
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