In this work, pristine graphene oxide and its thermally reduced derivatives, rGO, were tested for the removal of triazines (atraton, prometryn, and atrazine) from water. The reduction process was optimized by means of design of experiments (DOE) coupled with response surface methodology (RSM), relying on the adsorption efficiency of the material. The optimal reduction conditions were calculated at a temperature of 110 °C maintained for 24 h; the mildest and simplest reduction protocol was chosen, as it allows in-air heat treatment with a common laboratory oven. The rGO samples were characterized before use, confirming a partial reduction process that, leaving intact most of the oxygenated functionalities on the graphene skeleton, may still allow favorable adsorption of pollutants through both hydrogen bonds and π–π interactions, which result from a large conjugated polyaromatic system. Triazine analyses were performed by high-performance liquid chromatography (HPLC); the data obtained from the adsorption isotherms were fitted with the Langmuir and Freundlich models, highlighting a slightly different adsorption behavior of atraton and prometryn compared with atrazine. Model outcomes were also used to support the hypotheses about the adsorption process.

In this work, triazines were chosen as the organic micropollutants model, to develop a useful method for the removal of triazine products, using a reduced derivative of graphene oxide as adsorbent material. The pristine graphene oxide and its thermally reduced derivatives under mild conditions were tested, optimizing the GO reduction conditions by means of DOE coupled with the response surface methodology. For the reduction it was decided to choose the mildest and simplest conditions possible, using an air heat treatment in a common laboratory oven. The optimal reduction conditions deduced from the response surface were calculated at a reduction temperature of 110 °C maintained for 24 hours and rGO sample was employed in the adsorption of the triazines. All the adsorbent materials have been characterized before use, by Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Brunauer-Emmett- Teller (BET) surface area analysis. Triazine analyses were performed by HPLC. The data obtained from the adsorption isotherms have been fitted with the Langmuir and Freundlich models, and the Freundlich model was the best one, especially for the Atraton and the Prometryn. The maximum adsorption capacity obtained was 4.4 mg/g for Atrazine, 19.4 mg/g for Atraton and 18.4 mg/g for Prometryn, at room temperature.