Green synthesis of CaCO 3 nanoparticles for photocatalysis and cytotoxicity.

In this study, Gum Arabic natural polymer was used to green synthesize calcium carbonate nanoparticles (CaCO 3 -NPs). Synthesized CaCO 3 -NPs were identified using various analyses such as FTIR, XRD, FESEM, EDX, and UV-Vis. The UV spectrum of nanoparticles showed an absorption band at a wavelength of 320 nm. FTIR analysis also confirmed the synthesis of nanoparticles. XRD studies showed that CaCO 3 -NPs have a rhombohedral crystalline structure with space group R-3c and an average size of about 42 nm. FESEM images showed that CaCO 3 -NPs have cubic morphology and EDX results confirmed the presence of carbon, calcium, and oxygen elements. The synthesized CaCO 3 -NPs showed good photocatalytic activity to methylene blue (MB) dye degradation, which percentage degradation was 93% after 120 min. Also, the cytotoxicity of CaCO 3 -NPs has been examined on the normal L929 and cancer CT26 cell lines and the IC 50 value was about 250 µg/mL for cancer cells.