Determination of iodine number of activated carbon by the method of ultraviolet–visible spectroscopy

This paper reports a feasible method for determining the iodine number of activated carbon by ultraviolet–visible (UV–vis) spectroscopy. The experiment based on the measurement of absorbance at 288 and 350 nm for triiodide ion, which generated by I2-I−-I3− close reaction system. The concentration ratio r (r = [I−]/[I2]), reaction time and reaction temperature has great influence on the absorbance of triiodide. To verify the accuracy of this method, the iodine number of three kinds of activated carbon materials was measured by titration and UV–vis spectroscopy according to three standard test methods, respectively. The relative deviation (RD) of the measurement results was within 2.6%, indicating that the UV–vis spectroscopy can be used as a tool of determining the iodine number of carbon materials, and it is of profound significance to improve the detection efficiency and accuracy.