Treatment of Humic Acid by Coagulation and Advanced Oxidation Processes

• Main Authors: Wan-Zhen Chen, 陳琬楨
• Other Authors: Hsing-Yuan Yen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/57389319993740862856

碩士 === 高苑科技大學 === 化工與生化工程研究所 === 98 === In this study, commercial humic acid was divided three solutions by UF membrane. The molecular weight <100K, <10K, and <1K, respectively. The removal of organic matters were evaluated by iron salts coagulation, Fenton oxidation, and H2O2/UV oxidation. Experiment variables studied include ferric and ferrous dosages at coagulation; ferrous dosage, oxidation time, the ratio of coagulation and oxidation at Fenton process; pH, oxidation time, H2O2 dosage, and UV intensity, THMFP, reaction kinetic, and specific energy consumption were assessed at H2O2/UV process. The coagulation results showed that the both ferrous and ferric dosages are 20mg/L. The DOC residual <100K, <10K, and <1K sample are 83%, 85%, 94% and 14%, 84%, 85%, respectively. The DOC removal by coagulation either ferrous or ferric is A> B > C solution. In addition, the pH was adjudged to 10 after Fenton process. The DOC was re-dissolution for the three solutions. Obviously, most of the DOC was coagulated by iron salts instead of Fenton oxidation. On the other hand, when pH 7, UV=128W, and H2O2 dosage is 50mg/L at an oxidation time of 60 min. H2O2/UV process mineralize the DOC of A, B, and C solution to a DOC residual of 5%, 11%, and 29%, respectively. Although all of the DOC of three samples are 10 mg/L, the THMFP are 162.5, 169.5 and 234.2 μg/L and reduce to 13.2, 16.4 and 28.3 μg/L after H2O2/UV oxidation. It indicates the H2O2/UV process mineralizes organic matters as well as reduce THMFP. Moreover, the specific energy consumption of 70% DOC removal are 4×103, 4.8×103 and 8.8×103 KWh/Kg for A, B, C solution, respectively. The specific energy consumption obviously increased with decreasing molecular weight of humic acid. The DOC removal followed pseudo-first order kinetic and reaction rate constants are 5.59×10-2, 4.14×10-2 and 2.37×10-2 min-1. In conclusion, regardless of iron salts coagulation, Fenton oxidation or H2O2/UV process the DOC removal decreased with decreasing molecular weight of humic acid.