Optimization of Five Reducing Agents using UV-VIS Spectrometry for Reduction of Iron(III) to Iron(II)

This study aims to investigate the optimum conditions of five reducing agents viz., sodium thiosulfate (Na2S2O3), hydroxylamine hydrochloride (NH2OH·HCl), ascorbic acid (C6H8O6), sodium oxalate (Na2C2O4) and sodium sulfite (Na2SO3) for the reduction of Fe(III) to Fe(II) using UV-Vis spectrometry. As result, the optimum pH of acetate buffer for Na2S2O3, NH2OH·HCl, C6H8O6, Na2C2O4 and Na2SO3 were obtained at pH 4.5, 4.5, 4.5, 5.0 and 4.0, respectively. Whilst the optimum time for each Na2S2O3, NH2OH·HCl and C6H8O6 were 15 min, the outcome for Na2C2O4 and Na2SO3 took longer time which are 45 and 30 min, respectively. As for optimum concentration, the results were various as Na2S2O3, NH2OH·HCl, C6H8O6, Na2C2O4 and Na2SO3 were at 11, 7, 5, 12 and 60 ppm in consecutive order. Also to conclude the work, the recovery percentage were calculated and the results were Na2S2O3 (102.81 %), NH2OH·HCl (116.71 %), C6H8O6 (97.97 %), Na2C2O4 (85.89 %), and Na2SO3 (85.04 %).