Preparation and dynamic adsorption properties of amphoteric cellulose porous hydrogel spheres
Objective Cellulose porous hydrogel spheres are increasingly used as adsorption fillers by virtue of their combined properties,which have become a current research focus.However,the preparation of these spheres is currently cumbersome and they exhibit limited adsorption efficiency and single adsorption species,restricting their applications.Therefore,it is important to develop a simple and efficient biomass adsorbent with both adsorption and separation capacity for ionic dyes.Method In this paper,amphoteric cellulose porous microsphere(ACM)was developed by a two-step chemical modification method of esterification and Schiff base reaction.The surface morphology,pore structure and mechanical properties of the hydrogel spheres were characterized and analyzed using field emission scanning electron microscopy,specific surface area and pore size distribution instrument and universal testing machine,respectively.The adsorption column device was constructed to investigate the adsorption properties of ACM.Results The specific surface area,pore size distribution and porosity of ACM with abundant pore structure on the surface and inside were 123.97 m2/g,0.633 cm3/g and 89.22％,respectively.The compressive strength of ACM was found to be 591.9 kPa at 30％compression deformation,and the mechanical properties were about 63％of the initial value after 40 cycles of compression.ACM showed good compressive strength as well as structural stability because the carboxylation reaction took place at a high temperature,which increased the skeletal density and strength of the hydrogel spheres.Cross-linking occurred during the two-step reaction,producing three-dimensional network structure that enhanced the mechanical properties.It was found that the dynamic adsorption efficiency of the adsorption column wase improved by reducing the initial concentration,increasing the loading height,and slowing down the feed rate.With 0.8 g hydrogel spheres it was possible to treat almost 7.5 L of dye containing wastewater.The hydrogel spheres were chemically modified in two steps to combine high porosity,high mechanical properties,and abundance of carboxyl/amino active groups.80％separation of mixed dyes was achieved by ACM,which possesses both carboxyl and amino active groups and has different adsorption properties under different acid and base conditions.Conclusion The influence of different device parameters on the dynamic adsorption of ACM was investigated,and it was found that the dynamic adsorption efficiency of the column could be improved by decreasing the initial concentration,increasing the loading height,and slowing down the feed rate.The final device parameters were determined as 50 mg/L inlet concentration,12 cm filling height and 4 mL/min inlet speed.0.8 g of hydrogel spheres could treat about 7.5 L of wastewater containing dye MeB at the optimum device parameters,demonstrating the good adsorption and separation performance of the ACM.
celluloseamphoteric hydrogel sphereadsorption separationanionic and cationic dyedynamic adsorption propertyprinting and dyeing wastewaterwastewater treatment
万方数据
维普
