Synthesis of magnetic tungsten disulfide/carbon nanotubes nanocomposite (WS2/Fe3O4/CNTs-NC) for highly efficient ultrasound-assisted rapid removal of amaranth and brilliant blue FCF hazardous dyes

In this research, the potentiality of magnetic tungsten disulfide/carbon nanotubes nanocomposite (WS2/Fe3O4/ CNTs-NC) as an adsorbent for the ultrasound-assisted removal of amaranth (AM) and brilliant blue FCF (BB FCF) dyes was investigated. The experiments were conducted using a central composite design (CCD) with the inputs of solution pH (X1: 2.0-10), adsorbent mass (X4: 4-20 mg), AM concentration (X2: 10-50 mg L-1), BB FCF concentration (X3: 10-50 mg L-1), and sonication time (X5: 2-12 min). At the optimum conditions, the removal percentages of 99.30% and 98.50% were obtained for AM and BB FCF, respectively. The adsorption of the dyes was described by Langmuir isotherm and pseudo-second-order (PSO) kinetic models. The maximum adsorption capacities of AM and BB FCF were 174.8 mg g-1 and 166.7 mg g-1, respectively. The adsorption thermodynamic study showed that the adsorption of the dyes occurred endothermically and spontaneously. The removal percentages of AM and BB FCF from the real samples were in the range of 94.52-99.65% for the binary solutions. The removal percentage for each dye after five cycles of adsorption/desorption was > 90%. This work provides a useful insight to the potential application of CNTs-based magnetic nanocomposite for the treatment of wastewaters contaminated with dyes.