Adsorption kinetics and Box–Behnken design optimization for organic dyes on tungsten oxide

Crystal Phase and Morphology-Controlled Synthesis of Tungsten Oxide Nanostructures for Remarkably Ultrafast Adsorption and Separation of Organic Dyes

“…At the end of predetermined time intervals, the solution was centrifuged at 11 000 rpm for 10 min, and the supernatant was examined using a UV–vis spectrometer at λ max = 664 nm (for MB), 617 nm (for MG), 518 nm (for SO), 580 nm (for CV), 553 nm (for RhB), 463 nm (for MO), 547 nm (for RB). The percentage (%) of dye adsorption was calculated using eq ,, % 0.25em 0.25em adsorption = C 0 − C t C 0 × 100 The equilibrium uptake was calculated using eq ,, q normale = ( C 0 − C t ) v w where q e represents the equilibrium adsorption capacity (mg·g –1 ) of the dye, C 0 and C t are the initial and equilibrium concentrations of adsorbate solution (mg·L –1 ), respectively, v is the volume of adsorbate test solution (L), and w is the weight of adsorbent (g). All of the results were analyzed at least three times to confirm the reproducibility.…”

“…The morphologies and formation of WO 3 ·(H 2 O) 0.5 and (NH 4 ) 0.33 WO 3 crystal phases were controlled by changing the solvent amount (H 2 O/ n -propanol), thereby changing the internal pressure of the autoclaves during the solvothermal reactions. − In addition, the adsorption properties of WO 3 nanoplates and nanospheres were studied using methylene blue (MB), a cationic dye, as a model molecule. The (NH 4 ) 0.33 WO 3 nanospheres exhibited an exceptionally high adsorption rate constant ( K 2 ) of 17.24 g·mg –1 ·min –1 in an aqueous medium at neutral pH, the highest reported to date for WO 3 -based nanomaterials to the best of our knowledge. ,− ,− …”

“…At the end of predetermined time intervals, the solution was centrifuged at 11 000 rpm for 10 min, and the supernatant was examined using a UV−vis spectrometer at λ max = 664 nm (for MB), 617 nm (for MG), 518 nm (for SO), 580 nm (for CV), 553 nm (for RhB), 463 nm (for MO), 547 nm (for RB). The percentage (%) of dye adsorption was calculated using eq 1 30,34,48 C C C % adsorption 100…”