Citrus pectin as a template for synthesis of colorful aluminates

Synthetic inorganic pigments based on citrus pectin and metal (aluminum, iron, cobalt, and nickel) nitrates were prepared by a novel, fast, economical synthesis method that did not generate wastes. It involved gelling at 80 °C (4 h) and calcination at 600 °C (3 h). Samples' thermal (TG/DTA) and morphological (SEM) behaviors, size distribution (DLS), surface areas and porosities (BET), molecular spectroscopic (Raman spectroscopy) and electronic (UV-Vis spectroscopy) behaviors, and colors (CIELab) were investigated. Characteristic data indicated pigments had morphologies typical of porous materials with 1.40-1.64 μm particle size, which is ideal for pigment applications. Thermal curves showed an organic fraction after calcination at 600 °C, which gave a softness to the pigments. Cytotoxicity tests revealed that toxicity was within tolerable limits, and dispersion tests in commercial colorless paint showed increasing coating capacity with decreasing paint volume while maintaining color, as verified by colorimetric measurements.