Enhanced Sonocatalytic Performance of Non-Metal Graphitic Carbon Nitride (g-C 3 N 4 )/Coconut Shell Husk Derived-Carbon Composite

This study focused on the modification of graphitic carbon nitride (g-C 3 N 4 ) using carbon which was obtained from the pyrolysis of coconut shell husk. The sonocatalytic performance of the synthesized samples was then studied through the degradation of malachite green. In this work, pure g-C 3 N 4 , pure carbon and carbon/g-C 3 N 4 composites (C/g-C 3 N 4 ) at different weight percentages were prepared and characterized by using XRD, SEM-EDX, FTIR, TGA and surface analysis. The effect of carbon amount in the C/g-C 3 N 4 composites on the sonocatalytic performance was studied and 10 wt% C/g-C 3 N 4 showed the best catalytic activity. The optimization study was conducted by using response surface methodology (RSM) with a central composite design (CCD) model. Three experimental parameters were selected in RSM including initial dye concentration (20 to 25 ppm), initial catalyst loading (0.3 to 0.5 g/L), and solution pH (4 to 8). The model obtained was found to be significant and reliable with R 2 value (0.9862) close to unity. The degradation efficiency of malachite green was optimized at 97.11% under the conditions with initial dye concentration = 20 ppm, initial catalyst loading = 0.5 g/L, solution pH = 8 after 10 min. The reusability study revealed the high stability of 10 wt% C/g-C 3 N 4 as sonocatalyst. In short, 10 wt% C/g-C 3 N 4 has a high potential for industrial application since it is cost effective, reusable, sustainable, and provides good sonocatalytic performance.