Ultrasound-assisted adsorption of Sunset Yellow CFC dye onto Cu doped ZnS nanoparticles loaded on activated carbon using response surface methodology based on central composite design

Removal of noxious Sunset Yellow CFC (SY) from the liquid phase using Cu doped ZnS nanoparticles loaded on activated carbon (Cu: ZnS-NPs-AC) was well examined and investigated. The adsorbent was characterized using various analytical techniques such as Field emission Scanning electron microscopy, Fourier transform infrared spectroscopy and X-ray diffraction. The very good fitting of developed equation for prediction of experimental data is judged with their acceptable R-2 adjusted correlation coefficients (R-2-Adj: 0.9941). The predicted model show maximum SY removal conditions adjusted at 6.0, 0.025 g, 20 mg L-1 and 3 min) correspond to pH, adsorbent dosage, SY concentration and sonication time, respectively. From the results obtained it was found that the removal of Sunset Yellow CFC dye show positive relation with adsorbent i.e. with increase in adsorbent dose, removal efficiency increases and negative trend with the initial SY concentration i.e. with decrease in initial SY concentration, removal efficiency decreases. Additionally increase in SY removal on increasing the sonication time lead to simultaneous increase in SY diffusion coefficient. The adsorption equilibrium and kinetic data was found to be in well fitted and in good agreement with Langmuir isotherm and pseudo-second-order reaction kinetic model. The results from the studies of sequential adsorption-desorption cycles showed that Cu: ZnS-NPs-AC adsorbent held good desorption and reusability. (C) 2016 Elsevier B.V. All rights reserved.