Novel environment friendly inorganic red pigments based on attapulgite

Abstract

Novel environment friendly inorganic hybrid pigments with bright red colors and good stability were successfully prepared by a one-pot hydrothermal reaction of natural attapulgite (APT) with Fe(III) salts, without addition of any chemical precipitants. It has been revealed by systematic structure characterizations that APT is essential to form the red hybrid pigment, and the Fe2O3 nanoparticles were in-situ formed and anchored on APT to form a stable composite. The hybrid pigment with the composition of 29.61% SiO2 and 68.37% Fe2O3 showed bright red color with the a* coordinate value of +36.3, which was better than the same kinds of commercial red pigments. The color of the hybrid pigments can be tuned by only altering the dosage of Fe(III) or reaction time, and accordingly a series of hybrid pigments with the colors of light amber, orange red and bright red were obtained. Moreover, the red hybrid pigments can tolerate lights, acids, alkalis and organic solvents, and suspend well in water and alcohol media, and are able to be easily coated on different substrates, e.g., glass, wood, ceramic, cotton fabric, and paper.