Effect of Tannic Acid on Photocatalytic Efficiency of NiFe2O4 and ZnO

ZnO, NiFe 2 O 4 , NiFe 2 O 4 /TA and NiFe 2 O 4 /TA/ZnO photocatalyts were successfully synthesized and characterized, and they demonstrated significant photocatalytic efficiency under visible-light. The photodegradation rates of congo red (CR) are 35.7%, 19.4%, 25.5% and 91.1% over the ZnO, NiFe 2 O 4 , NiFe 2 O 4 /TA and NiFe 2 O 4 /TA/ZnO for 180 min, respectively. The results display that the NiFe 2 O 4 /TA/ZnO has the most excellent photocatalytic efficiency for CR among to the other photocatalysts. Furthermore, NiFe 2 O 4 /TA/ZnO may be separated easily from solution by magnet because of the magnetic property of NiFe 2 O 4 . The considerable increment in efficiency of NiFe 2 O 4 /TA/ZnO can be attributed to synergistic effects between NiFe 2 O 4 , the tannic acid (TA) and ZnO, which extend lifetime and hinder the recombination of photogenerated charge carriers. This work presents new perspectives on the use of tannic acid based magnetic photocatalysts in wastewater treatment.