Preparation and photocatalytic activity of hematite from iron sand modified ZnO for indigo carmine degradation

Modification of hematite (alpha-Fe2O3) with ZnO to produce ZnO/alpha-Fe2O3 composites by sol gel method and their photocatalytic activity testing on the degradation of indigo carmine (IC) dye has been done. The hematite was extracted from iron sand using hydrochloric acid and precipitated using aqueous ammonia. The ZnO/alpha-Fe2O3 composites were prepared with the mole ratio of ZnO to alpha-Fe2O3 1:1, 1:5 and 5:1. XRD pattern analysis showed that the average crystallite size of ZnO/alpha-Fe2O3 composites were greater than that of alpha-Fe2O3. The result of photocatalytic activity test showed that composite with the mole ratio of ZnO to alpha-Fe2O3 1:5 has the highest photocatalytic activity under the optimized conditions, with the maximum degradation efficiency of IC are 91.75 % and 93.18 % under UV light and sunlight irradiation, respectively. These highest of photocatalytic activity was reached at the initial pH of dye solution = 1, photocatalyst dosage of 300 mg, initial dye concentration 15 ppm and irradiation time 120 minutes under UV light and 90 minutes under sunlight irradiation.