Studies on the removal of dyes from water using carbon nitride/graphene oxide composites as adsorbents

Resumo

Dyes in water are a currently environmental concern, such as basic blue 26, being indispensable to remove it from water. Graphene oxide and carbon nitride are potential filtering agents to pollutant removal. Therefore this study aimed optimizes the dye sorption process in water using carbon nitride and oxide graphene composites. The GO/CN composites (30/70, 50/50 and 70/30) were obtained by dispersing the materials in water, under stirring and sonication. It was evaluated the removal of three different basic dyes: Green 4 (BG4), Brown 4 (BB4) and Blue 26 (BB26) and two types of CN adsorbent (called RCN and RHS). Carbon nitride CN e RHS have pore volume of 0.88 and 0.48 cm3/g and surface area of 200.3 and 164.5 m2/g, respectively. The highest removal efficiency occurred in the tests with BB26 dye. Concerning the two CN, the most porous material (RCN) was the best BB26 adsorbent. In addition, BB26 adsorption experiments were carried out with different materials: pure GO and CN and the GO/CN composites. The best BB26 adsorbent was the composite GO/CN 50/50, which reached a removal capacity of 390 mg/g. Due to the best results, the composite GO/CN 50/50 was chosen to the optimization process. The obtained results indicated the high removal capacity of ~700 mg/g and removal of 99% at 0.3 g/L adsorbent loading. We conclude that the optimized scenario to run the BB26 dye removal is using the GO/CN (50/50) composite is the time of 60 minutes, adsorbent load of 0.1 g/L.