A Sustainable Route to Synthesize Graphene Oxide/Ordered Mesoporous Carbon as Effect Nanocomposite Adsorbent

Rice husk is an agricultural waste that provides an alternative renewable source of bioenergy. Burning rice husk can produce rice husk ash. The rice husk ash is a potential resource of low-cost precursor for synthesizing high value-added materials. This paper reports the synthesis of SBA-15 mesoporous silica from recycled rice husk ash waste. Next, graphene oxide/ordered mesoporous carbon (GO/CMK-3) nanocomposite was synthesized using the SBA-15 template. The composite was investigated by X-ray diffractometer, field-emission scanning electron microscope, transmission electron microscopy, Fourier transform infrared spectrometer, Raman spectrometer and surface area analyzer. Experimental results confirmed that GO/CMK-3 composite possessed high surface area (936 m²/g), large pore volume (1.077 cm³/g), and uniform pore size (4.35 nm). The mesopore structure was not destroyed by the introduction of GO. Methylene blue was employed as an adsorbate to evaluate the adsorption capacity of GO/CMK-3 composite. The GO/CMK-3 revealed much higher adsorption capacity levels than did pure CMK-3 and SBA-15. The adsorption capacity decreased with increasing solution temperature, and increasing initial concentration of dye. The thermodynamic observation indicated that the total adsorption process was spontaneous and exothermic. The conversion of rice husk ash waste into GO/CMK-3 composites can be regarded as an economically beneficial by-product for reducing environmental pollution.