The effect of pH on the properties of 3D welan gum–graphene oxide composite hydrogels and their excellent adsorption capacity

In this article, welan gum–graphene oxide (GO) composite hydrogels were prepared by simple self-assembly of these two components in aqueous media and the effects of pH on their properties were systematically studied. The welan gum–GO hybrid hydrogels with different pH have been thoroughly characterized using TEM, FE-SEM, FT-IR spectroscopy, XRD and rheological measurements. It can be observed that the microstructures of welan–gum hydrogels can be tailored by varying the pH value and swelling properties analysis shows that the swelling ratio increases with pH. Moreover, the welan gum–GO hybrid hydrogels exhibited improved adsorption properties for water-soluble dyes under acidic conditions than under basic conditions. At the same time, adsorption isotherms and kinetics were also studied. Thus, it is expected that the GO-based composite hydrogels can act as potential adsorbents and have promising applications in the field of waste water treatment by adjusting pH.