Optical properties of calcium chromate 1D-nanorods synthesized at low temperature from secondary resources

Abstract Calcium chromate 1D-nanorods have been synthesized from tannery waste solution. The solution was filtered to get rid of insoluble matters followed by addition of ammonia to precipitate calcium and chromium as hydroxide gel. The gel was heated within the temperature range 300–600 °C. At 300 °C amorphous phase of calcium chromate was formed. At 400 °C compounds of CaCrO 4 , Cr 2 O 3 , CaCO 3 and minor amount of Mg 2 CO 3 (OH) 2 (H 2 O) 3 (Artinite) were detected. At 500 °C, CaCrO 4 compound was the major product together with traces of Cr 2 O 3 , CaCO 3 and MgO. At 600 °C, a crystalline compound of CaCrO 4 was formed. Nanorods of calcium chromate structured during heating associated with the crystal growth. Properties of heated products are evaluated with the help of XRD, TEM and FT-IR measurements. Optical properties of the obtained calcium chromate were estimated. A thermodynamic model of the involved reactions is suggested to explore the findings.