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.