Application of copper sulfide nanoparticles loaded activated carbon for simultaneous adsorption of ternary dyes: Response surface methodology

Copper sulfide nanoparticles were synthesized and loaded on activated carbon (CuS-NPs-AC) for ternary dye removal. Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD) and scanning electron microscopy (SEM) equipped with energy-dispersive X-ray spectroscopy (EDX) were used to characterize the synthesized materials. The performance of the materials was subsequently evaluated for simultaneous ultrasound assisted adsorption of Disulphine Blue (DB), Eosin Yellow (EY) and Safranin O (SO) dyes in ternary solution under different conditions that include variation in solution pH, initial concentrations of dyes, sonication time and adsorbent dosage. Response surface methodology (RSM) using central composite design (CCD) was employed to obtain the optimum experimental conditions. The maximum removal efficacies (88.39%, 68.49% and 55.69% for DB, EY and SO, respectively) were found at the optimum conditions: 3.63 min of sonication time, 0.02 g of CuS-NPs-AC, 7.76mg L-1 of DB, 8.89mg L-1 of EY, 9.87mg L-1 of SO and pH 6.5. Very high adsorbent capacities of 198.12, 165.0, 139.58mg g-1 for DB, EY and SO, respectively, were yielded from Langmuir isotherm as best fitted model. Kinetic study indicated that the pseudo-second-order kinetic model was well fitted to the experimental data of ternary adsorption process. The results of the study display very good adsorption efficiency of the synthesized adsorbent for dye removal with high adsorption capacity under optimum conditions.