Synthesis and characterization of multi-responsive poly(N-isopropylacrylamide)-sodium alginate-graphene oxide composite hydrogels

The multi-responsive ternary poly(N-isopropyl acrylamide) (PNIPAM)/ /sodium alginate (SA)/graphene oxide (GO) composite hydrogels were prepared. The influence of GO content on the microstructure and physical properties of the composite hydrogel was researched. The ternary composite hydrogels exhibited significantly larger mechanical strength and higher water uptake compared to binary PNIPAM/SA composite hydrogels. The effects of temperature, pH, and contact time on the adsorption capacity of rhodamine B (RB) for the PNIPAM/SA/GO ternary composite hydrogels were further investigated. The adsorption kinetic and isotherm for the adsorption behavior of the ternary composite hydrogel were well fitted with the pseudo-second-order kinetic model and Langmuir model, respectively. Besides, the PNIPAM/SA/GO ternary composite hydrogel could be easily removed from the dye solutions and reused without the obvious decrease of its performance. It indicated that the ternary composite hydrogel could serve as an effective adsorbent for the removal of organic pollutants.