Application of reduced graphene oxide/ natural rubber composite for petroleum removal in sea water

Abstract

In this study, the natural rubber (NR) composite foam was prepared to enhance oil adsorption performance of NR foam. The reduced graphene oxide (rGO) was synthesized from graphite waste by oxidation and reduction processes. In the oxidation step, different oxidation conditions (thermal-sonication and stirring-sonication) were studied in order to achieve the highest interlayer spacing in graphite structure. Then, the reduction was carried out using L-ascorbic acid (L-AA) as a reducing agent. Furthermore, morphology and surface properties of the synthesized rGO were investigated. To prepare the NR composite foams, NR latex was mixed with various contents of rGO (0.25, 0.5, 1.0 and 1.5 parts by weight per hundred part of rubber: phr). The results showed that the amount of rGO affected the morphology and the oil adsorption capacity of NR composite foams. The optimum amount of rGO in the NR composites foam which exhibited the highest oil adsorption performance was 0.5 phr. The oil adsorption capacity of NG-0.5 for gasohol, kerosene, crude oil, diesel and fuel was 21.50, 19.31, 17.04, 16.53 and 10.09 g g-1, respectively. In addition, the effect of temperature and turbulence on the oil adsorption capacity of the NR composite foams was determined. Three kinetic models, i.e. pseudo-first-order, pseudo-second-order and Elovich equation, were examined. The pseudo-second-order presented the better fit with the experimental data. The Langmuir isotherm was an appropriated model to predict the oil adsorption behavior of the NR composite foams. Finally, reusability feature of the NR composite foams was also studied through fifteen oil adsorption-desorption cycles. The result showed that the NR composite foams could be reused in many times.