Investigation of Photocatalytic Reduction of Cr (VI) from Aqueous Solutions by Using Green Iron Nanoparticles:A Laboratory Study

Hexavalent chromium (Cr (VI)) is a highly toxic pollutant that isknown as a carcinogen and mutagen agent to humans. Photocatalytic reduction is one of the known ways to remove these contaminants. Therefore, the aim of this study was to investigate the catalytic effect of green iron nanoparticles, as eco-friendly materials, on photocatalytic reduction of Cr (VI) from wastewater.
This is a laboratory study that has been done using a batch reactor with a 400 ml useful volume and medium pressure UVC lamp. Iron nanoparticles were synthesized using barberry leaf extract and iron chloride, then their performanceswere investigated in photocatalytic reduction process of hexavalent chromium. In this study the effect of different parameters such as pH (2-10), catalyst dosage (0-0.375g/l), reaction time (2-15min),and initial Cr (VI) concentration (10-200 mg/l) were investigated. The size of the green iron nanoparticles were determined by Transmission Electron Microscope (TEM) analysis. Data Analysis was performed by Excel software.
TEM analysis showed that the production of green nanoparticles of iron has been successful and their size was from 20 to 40 nm. The optimum pH equaled 2. The best conditions for the process obtained in initial chromium concentration of 50 mg/l, catalyst dose of 0.375 g/l, and contact time of 15 minutes and removal efficiency of 100% was reported in this condition. Photocatalytic reaction kinetics followed the second order kinetic equation.
The results showed that green iron nanoparticles are efficient catalysts in the process of photocatalytic reduction of Cr (VI) from Synthetic wastewater.