Characterization of Factors AffectingElectrochemical Degradation 2,4-Dichlorophenol by Granular Graphite Electrodes

• Main Authors: Jin-Long Liao, 廖晉瓏
• Other Authors: 陳建隆
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/29308200004261777035

碩士 === 逢甲大學 === 環境工程與科學所 === 98 === Factors affecting the efficiency of electrochemical degradation of 2,4-dichlorophenol using granular graphite electrodes were evaluated in this research. The factors studied include applied current, hydraulic retention time, initial concentration, and pH. The experiments were conducted using the Design of Experiment approach (DOE): four factors with two levels and two repetitions for each condition. Two responses were used to evaluate the effect of the factors: surface reaction rate constant (k′) and surface concentration on graphite surface after adsorption (Cs). The results were evaluated first with the one-factor-at-a-time (OFAAT) approach. The k′ increases with the applied current, whereas it decreases with the hydraulic retention time, initial concentration, and pH. Based on the p-value of the experiments, hydraulic retention time has the highest significant effect k′, followed by the applied current, initial concentration, and pH. The highest significant effect of adsorption is pH, followed by initial concentration and hydraulic retention time, hydraulic retention time is not significant. Using the DOE analysis, interactions between the factors were significant (p < 0.05). The applied current(A), hydraulic retention time(B), initial concentration(C), and pH(D), Those interactions AB,AC,AD,BC,BD,CD,ABC,ABD, and ABCD are significant. The effect of the interaction between the hydraulic retention time and pH is even higher than that of pH along, meaning the OFAAT approach was unable to characterize the effects of individual factor at levels other than the levels used in the experiment. In other words, the OFAAT is not a robust approach. The DOE approach is necessary when optimizing the k′. Using the results from this study, the optimal condition for highest k′ is at a applied current of 150 mA (high level),hydraulic retention time of 3.55 min (low level) , initial concentration of 150 ppm(high level), and pH of 5(low level).