等离子体高级氧化技术去除饮用水中土霉味物质

嗅味已成为我国饮用水的主要水质问题之一,其中2-甲基异莰醇(2-MIB)、土臭素(GSM)等导致的土霉味是最常发生的嗅味问题,且往往难于有效去除。以5种典型土霉味物质2-异丙基-3-甲氧基吡嗪(IPMP)、2-异丁基-3-甲氧基吡嗪(IBMP)、2-MIB、三氯茴香醚(TCA)和GSM为目标,考察了等离子体高级氧化技术同时去除5种物质的效果、影响因素和氧化机理。结果表明:在初始浓度为500 ng/L、p H值为7. 5、脉冲放电电压为25 k V、频率为500 Hz条件下,氧化处理10～15 min即可将5种物质浓度降低到嗅阈值以下,氧化效果为TCA <2-MIB

Removal of Earthy/Musty Odor Compounds in Drinking Water Using an Advanced Oxidation Process Based on Plasma

Taste and odor problems have become a major water quality problem in drinking water in China. The earthy/musty odor problem caused by 2-methylisoborneol ( 2-MIB ) and geosmin is most commonly encountered. Five typical earthy/musty odor compounds, including 2-isopropyl-3 - methoxypyrazine (IPMP), 2-isobutyl-3-methoxypyrazine (IBMP), 2-MIB, trichloroanisole ( TCA), and geosmin were selected for the removal evaluation using an advanced oxidation process based on plasma. Additionally, the removal efficiency, influencing factors, and oxidation mechanism were investigated. The results demonstrated that the five investigated odor compounds were reduced below odor thresholds after 10 - 15 min discharge at an initial concentration of 500 ng/L, pH of 7. 5 , voltage of 25 kV and supply frequency of 500 Hz. The removal efficiency in ascending order was: TCA < 2-MIB < IPMP < IBMP < geosmin. Frequency and the initial pH of the solution had a great impact on the removal of earthy/musty odor compounds. With the increase of frequency, the oxidation rate of earthy/musty odor compounds increased , but the energy efficiency decreased. IPMP and IBMP were oxidized at the highest rate at pH of 6. 05 , while that of 2-MIB, TCA, and geosmin at pH of 9. 04. H2O2 and ozone were the main active product during discharge process and hydroxyl radicals (·OH) were produced by the further reaction between H2O2 and ozone, which played a major role in the oxidation process. Furthermore, all five earthy/musty odor compounds were effectively reduced to below odor thresholds within 10 - 15 min when using real source water.