Efficient treatment of anthraquinone dye wastewater by adsorption using sunflower torus-like magnesium hydroxide microspheres

摘要

Novel sunflower torus-like magnesium hydroxide (MH) microsphere particles were prepared by a facile one-step, self-assembly method. The synthesized products and the mechanism of adsorption of samples of the anthraquinone dyes reactive blue 19 (RB19) and alizarin red S (ARS) were analyzed by different modern characterization techniques, such as X-ray diffractometry (XRD), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), energy dispersive X-ray spectrometry (EDS), the Brunauer-Emmett-Teller (BET) method and Fourier transform infrared (FT-IR) spectroscopy. The adsorptive potential of the as-prepared microspheres for the removal of RB19 and ARS in aqueous solution was evaluated. The effects of multiple condition parameters, including, adsorbent dosage, adsorption time, adsorption temperature, wastewater pH, rotating speed and sodium chloride concentration on the removal of the dyes from the wastewater were studied in detail. The effect of the structural and shape properties of the MH adsorbent on the dye adsorption performances was also studied. The results showed that sunflower torus-like MH was an effective adsorbent for dye removal. The removal rates of ARS and RB19 were 91.65% and 83.03%, respectively, under the optimized conditions. The maximum adsorption capacity of the microspheres was 349.85 mg/g for ARS and 231.78 mg/g for RB19 at 25 degrees C. The equilibrium adsorption experimental data of the microsphere adsorption conformed to the Freundlich isotherm for ARS and the Langmuir isotherm for RB19. The adsorption kinetics experimental studies showed that the pseudo-second-order and pseudo-first-order model perfectly fit for both ARS and RB19 microsphere adsorption. RB19 and ARS were absorbed on the sunflower torus-like MH surface via the formation of H-bonds. Thus, the sunflower torus-like MH microsphere particles are an effective purifying agent for the removal of the anthraquinone dyes ARS and RB19 from wastewater.