Electrolytic Coloration And Spectral Property Of Ammonium Alum And Sucrose Crystals

Ammonium alum and sucrose crystals were colored at various temperatures（nearroom temperatures） and voltages using electrolysis method. Many radicals wereproduced in the colored crystals. Absorption spectra of the colored crystals weremeasured and analyzed systematically, and the production and transformationmechanisms of the radicals were presented. By using measured current time curves, theproduction and transformation mechanisms of the radicals were explained further.After electrolytic coloration using a pointed cathode, a lot of SO3, SO2, O3–andsmall charged radicals and electrons were produced in the colored ammonium alumcrystals. The successful electrolytic coloration of ammonium alum crystals shouldmainly benefit from the appropriate electrolysis temperatures and voltages and theunique graphite anode matrix. Many radicals were produced firstly in crystal regionsnear the anode matrix, and partial SO3, SO2radicals diffuse to other regions ofammonium alum crystals through exchanging electrons, O0and O radicals withneighboring SO42radicals. Data of current time were recorded during the electrolysis,with which current time curves are plotted. The current components to all the currentzones consist of the electron exchanges from the electrons and charged radicals to anodematrix. The formation mechanism of the current zones in the current time curves andthe close relationship between the color center production and the formation of thecurrent zones are presented. After varied experiments, in conclusion, a best effectivecoloration condition at temperature80oC, voltage1100V and electrolysis time40minis found. Electrolytic coloration of ammonium alum crystals using a pointed anode issimilar to that using a pointed cathode. The best effective coloration condition attemperature85oC, voltage1100V and electrolysis time60min is found.After electrolytic coloration using a pointed cathode, glycosylamines, caramels,carbonyl compounds and free radicals are produced in colored sucrose crystals. Thesuccessful electrolytic coloration of sucrose crystals should mainly benefit from theappropriate electrolysis temperatures and voltages and the unique graphite anode matrix.Some sucrose molecules decompose thermally directly into glucose and fructoseanhydride molecules, and other sucrose molecules decompose thermally into glucoseand fructose molecules. Under electrolysis conditions, some solid phase reactions, suchas caramelization and Maillard reactions, occur in colored sucrose crystals. Glycosylamines, caramels and carbonyl compounds were produced in colored sucrosecrystals. Data of current-time were recorded during the electrolysis, with whichcurrent time curves are plotted. Various charged radicals move toward thecorresponding electrodes with reversed polarities and exchange electrons with theelectrodes. The formation mechanism of the current zones in the current-time curvesand the close relationship between the color center production and the formation of thecurrent zones are presented. After varied experiments, in conclusion, a best effectivecoloration condition at temperature130oC, voltage1100V and electrolysis time45minis found. Electrolytic coloration of sucrose crystals using a pointed anode is similar tothat using a pointed cathode. The best effective coloration condition at temperature120oC, voltage1100V and electrolysis time60min is found.