| 摘要: | 高鐵酸鉀（六價鐵）為一種新型淨水氧化劑，能有效地除去水中的懸浮物、重金屬及多種有機污染物，高鐵酸鉀與污染物反應後不會產生任何有害物質，且對水生生物的呼吸作用沒有不良影響，是一種集氧化、吸附、混凝、助凝、殺菌、除臭為一體的多弁鉭韘滮臛B理劑。其製作方法可由濕式氧化法來合成，其原理乃利用次氯酸在強鹼下，把三價鐵氧化成六價鐵離子，並在高濃度之KOH溶液下使高鐵酸鉀固體沉澱出來，之後可用鉻滴定法標定高鐵酸鉀之純度。
本研究探討高鐵酸鉀在不同pH、莫耳數比及溫度條件下，對於苯環類化合物包括苯胺、間-苯二胺、Reactive Orange-16和Reactive Black-5之ADMI及其COD之去除率。實驗結果顯示當pH=9和10時，高鐵酸鉀對於苯胺、間-苯二胺和Reactive Black-5之ADMI的去除率最佳，而Reactive Orange-16之ADMI的去除率則會隨pH值升高而增加，不過在pH=10或11時去除率差值不大。另外，如果高鐵酸鉀的濃度增加，則對此四種化合物的去除率也會跟著增加，但去除率增加的幅度卻有所不同，大致上為高鐵酸鉀的濃度增加倍數與去除率增加幅度呈反比。至於高鐵酸鉀對於苯胺、間-苯二胺、Reactive Orange-16和Reactive Black-5之ADMI及其COD的最高去除率出現條件如下，苯胺：在pH=9和10，且高鐵酸鉀與苯胺的莫耳比為2：1時，苯胺去除率為100%；而在pH=10，且高鐵酸鉀與苯胺的莫耳比為4：1時，COD去除率為58%。間-苯二胺：在pH=10，且高鐵酸鉀與間-苯二胺的莫耳比為3：1時，間-苯二胺去除率為100%；而在pH=10，且高鐵酸鉀與間-苯二胺的莫耳比為5：1時，COD去除率為48%。Reactive Orange-16之ADMI：在pH=10，且高鐵酸鉀與Reactive Orange-16的莫耳比為5：1時，ADMI去除率為98%；而在pH=11，且高鐵酸鉀與Reactive Orange-16的莫耳比為5：1時，COD去除率為27%。Reactive Black- 5之ADMI：在pH=9、10和11，且高鐵酸鉀與Reactive Black 5的莫耳比為5：1時，ADMI去除率為84%；而在pH=9，且高鐵酸鉀與Reactive Black -5的莫耳比為5：1時，COD去除率為18%。至於溫度的影響，其結果為高鐵酸鉀對於此四種化合物及其COD的去除率，在15℃時去除率最高，其次是25℃，而在35℃時去除率最低。因此高鐵酸鉀對於此四種化合物及其COD的去除率會隨反應溫度的降低而提高。
Potassium ferrate is a kind of new-type oxidant of water purification; it can remove suspended substance, heavy metal and many kinds of organic pollutants in water effectively. After reacting with pollutants, potassium ferrate will not produce any harmful substance, and it does not have harmful effects to aquatic biological breathing. Potassium ferrate is the integrative multi-functional green water treatment agent that is a kind of collection for oxidization, absorbability, coagulation, disinfection and deodorization. Potassium ferrate can be synthesiz- ed by wet oxidation method; its principle is that in strong base condition, ClO- can oxidize Fe3+ to Fe6+, and then add saturated KOH solution to precipitate solid potassium ferrate, after that the purity of potassium ferrate can be determined by the titration of chromium (III) method.
The study was to investigate the removal efficiencies of aniline, m-benzenediamine, and reactive orange-16, reactive black-5 of ADMI and COD by potassium ferrate at different pH, molar ratios and temperature conditions. Results show that the highest removal efficiencies of aniline, m-benzenediamine, reactive black-5 of ADMI occurred at pH=9 and 10. Moreover, the removal efficiency of reactive orange-16 increased with increasing pH, and the removal efficiencies were similar at pH=10 and 11.Besides, the removal efficiencies of benzene compounds increased with increasing initial concentration of potassium ferrate, but the increasing degree of efficiencies were not obvious.
The optimum conditions for removing aniline, m-benzenediamine, reactive orange-16 and reactive black-5 of ADMI and COD are shown as follows:
(1.) At pH 9~10 and a molar ratio (ferrate: aniline=2:1), ferrate could remove 100% of aniline, and also could remove 58% of COD at pH 10 and a molar ratio (ferrate: aniline=4:1).
(2.) At pH 10, ferrate could remove 100% of m-benzenediamine and 48% of COD at respective molar ratios (ferrate: m-benzenediamine =3:1 and 5:1).
(3.) At a molar ratio (ferrate: reactive orange-16=5:1), ferrate could remove 98% of ADMI and 27% of COD at pH 10 and 11, respectively.
(4.) At a molar ratio (ferrate: reactive black-5=5:1), ferrate could remove 84% of ADMI and 18% of COD at pH 9~11 and 11, respectively.
The removal efficiencies of benzene compounds and COD at temperature 15 0C were higher than those at temperature 35 0C. Therefore the oxidation of benzene compounds at low temperature was easier than that at high temperature. |
