Utilização de nanocompósitos obtidos a partir da cinza da casca do arroz e grafeno para remoção de moléculas de interesse ambiental da água

Abstract

Rice husk ash (RCA) is a waste product that has great potential for application in several areas, including water treatment. CCA can be used as an adsorbent composite, which has as its main objective the removal of contaminants present in water. One way to improve the efficiency of this material in adsorption is combining it with other sorbent materials, such as graphene or its derivatives, forming a composite material. Among the contaminants that can be removed by these sorbents is safranin, an organic dye widely used in the textile industry due to its dyeing properties. This dye can be harmful to the environment and human health if not treated properly before being discarded in bodies of water. In the present work, a new composite resulting from the combination of reduced graphene oxide (rGO) and CCA was developed, which was characterized and applied in the removal of safranin. The characterizations showed that the material obtained, called CCA-rGO, presents a synergistic behavior resulting from the union of precursor materials CCA and rGO, indicating that there is a chemical interaction between both. The kinetic study showed that the time required for adsorption equilibrium is 8 h for CCA and 25 h for rGO and CCA-rGO. The adsorption isotherms showed a sorption capacity of 148.89 mg/g for CCA-rGO, higher than the adsorption of CCA (49.34 mg/g) and rGO (37.03 mg/g) individually. In addition to the excellent sorptive capacity when combined with rGO, CCA has other advantages such as ease of obtaining, low cost and being an environmentally friendly product. The use of this adsorbent composite can be a viable and efficient alternative for the treatment of water contaminated with dyes, helping to minimize environmental impacts and promoting sustainability.