Cationic organic dyes adsorption on few-layer graphene produced by self-propagating high-temperature synthesis

The effectiveness of carbon nanomaterials in purifying water from organic dyes has been proven over the previous decade. However, the problem of industrial application of carbon nanomaterials has not yet been solved. This is primarily due to the high cost and low productivity of carbon nanomaterials synthesis methods. This article presents the thermodynamic and kinetic data of rhodamine 6G and methylene blue adsorption on few-layer graphene. Few-layer graphene was obtained by self-propagating high-temperature synthesis from cellulose. It is a promising method which is inexpensive and easy to scale. It was found that the studied few-layer graphene has a high adsorption capacity for both dyes, and the obtained values of adsorption capacity are higher than most of the studied carbon materials, such as carbon nanotubes or activated carbon. The most common adsorption models were used to describe the thermodynamics of the process. The kinetics of the process are described by a pseudo-second-order equation, which is quite common in graphene materials. The proposed adsorption mechanism is based on hydrophobic interaction between adsorbent and adsorbate with the formation of H-π and π-π bonds.