Acid and alkali extraction of trivalent chromium from titanium dioxide surface

In this work various experimental conditions to extract chromium from titanium dioxide surface using acid and alkali reagents were studied. The effect of type of reagents, concentration of reagents and solid-liquid ratio were investigated. It was found that the chromium extraction using acid reagent provided the higher recovery efficiency than that using alkali reagent. The maximum achievable of chromium extraction (100%) can be found in many experimental conditions using either nitric or sulfuric acids as extraction reagents. The solid-liquid ratio also played a major role in extracting chromium in which the extraction of chromium increased with decreasing solid-liquid ratio. The results also showed that percentage of chromium recovery was increased with increasing of nitric concentration. On the contrary, this maximum recovery percentage was reduced with the rising of sulfuric concentration. Findings from this study could also provide the beneficial information for extraction of other heavy metals from titanium dioxide surface.