Insight into the impact of interaction between attapulgite and graphene oxide on the adsorption of U(VI)

The broad production and extensive application of graphene oxide (GO) possibly raised concern over their potential environmental impacts. In this work, attapulgite (APT) as a typical fibrillar mineral was chosen to investigate the impact of interaction between APT and GO on the adsorption of U(VI). The adsorption capacity order was GO > APT+GO > APT, which achieved from adsorption isotherms, indicating adsorption capacity was related with interaction between APT and GO. Then systematical investigation on U(VI) adsorption at various environment factors (time, pH, and ionic strength) was employed on single adsorbent (APT) and heterogeneous aggregate (APT+GO). Adsorption kinetics displayed both U(VI) adsorption on APT and APT+GO were better fitted with pseudo-second-order kinetic model than the first-order kinetic model. The solution pH had a great influence on interaction between APT and GO. Ionic strength had more influence on U(VI) adsorption on APT than APT+GO, indicating outer-sphere surface complex was important on U(VI) adsorption on APT. The interaction mechanism between GO, APT and U(VI) was further investigated by spectroscopy and morphology analysis. This study provided new insights into the impact of interaction between minerals and GO on the adsorption of pollutant.