Abstract:

Rosin-based surfactant was prepared from rosin and the surfactant was used to regulate the crystal growth and synthesis Ni(OH)₂ with hierarchical nanostructures.The NiO microspheres were further prepared by using Ni(OH)₂ as the precursor.The structure of NiO was characterized by FT-IR, NMR, XRD, SEM and TEM. The porosity of NiO microspheres was determined by BET. The characterization results of FT-IR and UV showed that the hierarchical structure of NiO microspheres showed very high adsorption capacity for Congo red (CR).The maximum adsorption amount was 657.89 mg/g, which was much better than that of commercial NiO(337.18 mg/g).The results showed that the adsorption reached equilibrium after 10 min and the equilibrium adsorption capacity was 50 mg/g at pH value of 3 when the concentration of Congo red was 50 mg/L and the amount of NiO was 16.8 mg. The NiO adsorption of Congo red was in accordance with the Freundlich model and the adsorption is an endothermic process. The adsorption kinetics conforms to the quasi-second-order kinetic equation. The adsorption process is dominated by chemical adsorption. The adsorption efficiency was not obviously reduced after several cycles. The removal rate of adsorption Congo red was maintained by 98% after recyceling for 5 times.

Key words: rosin, surfactant, nano-NiO, nanospheres, adsorption