| With the development of industry and the improvement of people's living standard,a large amount of sewage has been discharged into rivers and lakes,which causes serious enviromnental pollution,among which soluble particles pollute the water most seriously.Therefore,the removal of soluble particles has become one of the most important steps in the process of wastewater purification,and adsorption is the lowest energy consumption and the best way to deal with the pollution.Cellulose,as an environmentally friendly renewable energy,has attracted more and more attention.Sodium alginate has strong adsorption ability to some particles and has a broad application prospect in the field of wastewater treatment.In this paper,the composite microspheres were prepared by using cellulose,sodium alginate and thiol-modified ?-Fe2O3 nanoparticles,which were characterized by SEM,FT-IR and particle size analyzer.Then the dynamic adsorption of phosphate in aqueous phase was studied by loading the composite microspheres into the chromatographic column.(1)The cellulose solution was prepared by mixing lint cotton pulp(?-cellulose>95%)with a cellulose solvent(7wt%NaOH/12wt%uera/81wt%H2O)in-12.5?.Then the cellulose microspheres(CM)were prepared by sol-gel method.The microspheres exhibit spherical shape and three-dimensional network structure.Their average particle sizes are 96.7?m,363?m and 409.3 ?m,respectively.(2)A series of sodium alginate/cellulose composite microspheres were prepared by sol-gel method and applied to the static adsorption of phosphate in the aqueous phase.According to the mass fraction of sodium alginate in the whole microsphere,the microspheres were named SACCMO,SACCM10,and SACCM20,respectively.The microspheres exhibit spherical shape and three-dimensional network structure.Their average particle sizes are 363?m,351?m and 360?m,respectively,and their average pore diameters are in the range of 2 to 5 ?m,and the average solid content of the microspheres is 3.81%,3.83%and 3.88%,respectively.It can be seen from the FT-IR spectrum that the cellulose does not chemically react with sodium alginate,but is physically combined into microspheres.The results of adsorption experiments show that sodium alginate and cellulose have a synergistic effect on the adsorption of phosphate in aqueous phase.The series sodium alginate/cellulose composite microspheres have strong adsorption properties for phosphate,and its adsorption capacity increases with the increase in the mass fraction of sodium alginate.The optimal adsorption temperature of microspheres is 296K(23?),and the optimal adsorption pH is 6.The adsorption capacity of composite microspheres under the optimal conditions is the strongest when the mass fraction of sodium alginate is 20%(SACCM20),and its adsorption efficiency can reach 85.58%.(3)MPTS-?-Fe2O3 was prepared by surface thiolation of ?-Fe2O3 nanoparticles with 3-mercaptopropyl-trimethoxysilane(MPTS).MPTS-?-Fe2O3/cellulose composite were prepared by sol-gel method.The composite microspheres are applied to the static adsorption of phosphate ions in the aqueous phase.The microspheres exhibit spherical shape and three-dimensional network structure.Their average particle sizes are 355?m,and their average pore diameters are in the range of 2 to 5 ?m,and the average solid content of the microspheres are 10.48%.It can be seen from the FT-IR spectrum that MPTS has been successfully modified to the surface of ?-Fe2O3.The composite mcrospheres have strong adsorption properties for phosphate.The optimal adsorption temperature of microspheres is 296K(23?),and the optimal adsorption pH is 6.Its adsorption efficiency under the optimal conditions can reach 87.04%.(4)The MPTS-?-Fe2O3/sodium alginate/cellulose composite solution was prepared by blending MPTS-?-Fe2O3,sodium alginate and cellulose.And MPTS-?-Fe2O3/sodium alginate/cellulose composite microspheres were prepared by sol-gel method.The composite microspheres are filled in a chromatography column and applied to the dynamic adsorption of phosphate in the aqueous phase.The microspheres exhibit spherical shape and three-dimensional network structure.Their average particle sizes are 362?m,and their average pore diameters are in the range of 2 to 5 ?m,and the average solid content of the microspheres are 3.92%.The results of dynamic adsorption test showed that the composite microspheres have strong adsorption properties for phosphate under the optimal adsorption conditions,and its adsorption efficiency under the optimal conditions can reach 92.49%.The adsorption rate of the phosphate solution by the composite microsphere chromatography column becomes slower first,then becomes faster,and finally becomes slower.And the composite microsphere chromatography column reached adsorption saturation at 90 minutes. |
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