Removal of rhodamine B from water by modified carbon xerogels

Carbon xerogels was synthesized in the process of polycondensation of resorcinol and formaldehyde. The material was subjected to surface oxidation by a solution of ammonium persulfate, functionalization with amine groups and impregnation with copper(II) chloride. The carbon xerogels were characterized by low-temperature nitrogen adsorption, X-ray diffraction, scanning electron microscopy and infrared spectroscopy. The content of oxygen functional groups on the surface of the materials studied was determined by the Boehm method. All carbon xerogels were used for rhodamine B adsorption from liquid phase. The maximum sorption capacities of the samples were in the range 91–132 mg/g. The most effective adsorbent of rhodamine B proved to be the sample modified with amine groups and copper(II) chloride. The increase in temperature was found to increase the sorption capacities of carbon xerogels towards rhodamine B, while the basic environment was conducive to its adsorption on xerogels. The sorption of rhodamine B is a spontaneous endothermic process.