Eco-friendly lake pigment from sappanwood: Adsorption study and its application as natural colorant for natural rubber toy balloon

Abstract

Due to the awareness of the impact of synthetic dye on human health and the environment, natural dye and lake pigment have attracted considerable attention from researcher. Herein, pink−red lake pigment from sappanwood was prepared using adsorption approach. The effects of initial pH, pH and concentration of brazilein solution, dosage of aluminium hydroxide, and adsorption time on adsorption were also explored. Results showed that the maximum adsorption capacity of 30 mg g-1 was achieved when 0.25%w/v of aluminium hydroxide and 100 mg L-1 of brazilein solution were applied. The adsorption kinetics and adsorption isotherm fitted the pseudo second order model and Langmuir isotherm, respectively. Additionally, this lake pigment can be utilized as a natural colorant for natural rubber toy balloons, which could made toy balloon safer for children than synthetic dye. Thus, our lake pigment can be an alternative choice of safe and environmental friendly colorant for products including toys.

Brazilein modified zinc oxide nanorods with enhanced visible light-responsive photocatalytic efficiency

“…The FTIR spectra of both ZnO and Bra-ZnO nanorods revealed vibration bands of the Zn-O bond at 400 cm -1 to 750 cm -1 [33], the broad band of O-H stretching mode of the hydroxyl group at 3000 cm -1 to 3600 cm -1 [19,33], and O-H bending mode of the hydroxyl group at 1640 cm -1 [19,33]. The results also showed the existence of brazilein molecules on the surface of the Bra-ZnO nanorods, with intensities of C=O at 1415 cm -1 and C=C bands at 1595 cm -1 and C-H band in the aromatic ring within the wavenumber range of 650 cm -1 to 860 cm -1 and aliphatic C-H band at around 2871 cm -1 to 2925 cm −1 were also observed [34][35][36]. Therefore, the interaction of brazilein molecules and ZnO nanorods surface occurred via hydrogen bonding.…”