化工学报
化工學報
화공학보
CIESC Jorunal
2015年
10期
3950-3956
,共7页
倪金雷%彭若帆%童少平%马淳安
倪金雷%彭若帆%童少平%馬淳安
예금뢰%팽약범%동소평%마순안
臭氧%双氧水%氧化%催化剂%二氧化钛%物相%自由基
臭氧%雙氧水%氧化%催化劑%二氧化鈦%物相%自由基
취양%쌍양수%양화%최화제%이양화태%물상%자유기
ozone%hydrogen peroxide%oxidation%catalyst%titanium dioxide%crystal phase%radical
研究了不同物相TiO2对H2O2/O3氧化效能的影响，目标有机物为羟基自由基探针化合物乙酸。结果表明，在初始pH为7.0和10.0时，加入TiO2反而降低了H2O2/O3的氧化效率，其中锐钛矿TiO2比金红石TiO2的减弱作用更为明显。当初始pH为3.0时，金红石TiO2能显著提高H2O2/O3的氧化效率，但锐钛矿TiO2影响不明显。机理分析表明，H2O2浓度及其衰减速率与乙酸的去除效率有很大的相关性。在pH为7.0和10.0时，两种物相TiO2均能加快H2O2的分解，其中锐钛矿TiO2作用更为显著。此条件下HO?2能有效引发臭氧分解产生羟基自由基，故H2O2过快分解反而降低了乙酸的去除效果。在pH为3.0时，H2O2去质子化反应困难，故O3/H2O2氧化效率极低， H2O2浓度也几乎不变。加入TiO2能明显提高H2O2的分解速率，相比金红石TiO2，锐钛矿TiO2使H2O2在5 min内基本分解完毕，但其对 H2O2/O3氧化效率几乎没有影响。饱和臭氧水分解速度的批处理实验也有相似的结果。由此可见，合适引发剂浓度可能是保证臭氧类高级氧化技术较高效率的关键，否则只会导致氧化剂的无效过快分解。利用氯化硝基四氮唑蓝法对比分析了酸性条件下H2O2/O3、锐钛矿TiO2/H2O2/O3和金红石TiO2/H2O2/O3体系产生超氧自由基(?O 2)的量，其大小顺序为：H2O2/O3<金红石TiO2/H2O2/O3<锐钛矿TiO2/H2O2/O3，这与前面结果吻合很好。
研究瞭不同物相TiO2對H2O2/O3氧化效能的影響，目標有機物為羥基自由基探針化閤物乙痠。結果錶明，在初始pH為7.0和10.0時，加入TiO2反而降低瞭H2O2/O3的氧化效率，其中銳鈦礦TiO2比金紅石TiO2的減弱作用更為明顯。噹初始pH為3.0時，金紅石TiO2能顯著提高H2O2/O3的氧化效率，但銳鈦礦TiO2影響不明顯。機理分析錶明，H2O2濃度及其衰減速率與乙痠的去除效率有很大的相關性。在pH為7.0和10.0時，兩種物相TiO2均能加快H2O2的分解，其中銳鈦礦TiO2作用更為顯著。此條件下HO?2能有效引髮臭氧分解產生羥基自由基，故H2O2過快分解反而降低瞭乙痠的去除效果。在pH為3.0時，H2O2去質子化反應睏難，故O3/H2O2氧化效率極低， H2O2濃度也幾乎不變。加入TiO2能明顯提高H2O2的分解速率，相比金紅石TiO2，銳鈦礦TiO2使H2O2在5 min內基本分解完畢，但其對 H2O2/O3氧化效率幾乎沒有影響。飽和臭氧水分解速度的批處理實驗也有相似的結果。由此可見，閤適引髮劑濃度可能是保證臭氧類高級氧化技術較高效率的關鍵，否則隻會導緻氧化劑的無效過快分解。利用氯化硝基四氮唑藍法對比分析瞭痠性條件下H2O2/O3、銳鈦礦TiO2/H2O2/O3和金紅石TiO2/H2O2/O3體繫產生超氧自由基(?O 2)的量，其大小順序為：H2O2/O3<金紅石TiO2/H2O2/O3<銳鈦礦TiO2/H2O2/O3，這與前麵結果吻閤很好。
연구료불동물상TiO2대H2O2/O3양화효능적영향，목표유궤물위간기자유기탐침화합물을산。결과표명，재초시pH위7.0화10.0시，가입TiO2반이강저료H2O2/O3적양화효솔，기중예태광TiO2비금홍석TiO2적감약작용경위명현。당초시pH위3.0시，금홍석TiO2능현저제고H2O2/O3적양화효솔，단예태광TiO2영향불명현。궤리분석표명，H2O2농도급기쇠감속솔여을산적거제효솔유흔대적상관성。재pH위7.0화10.0시，량충물상TiO2균능가쾌H2O2적분해，기중예태광TiO2작용경위현저。차조건하HO?2능유효인발취양분해산생간기자유기，고H2O2과쾌분해반이강저료을산적거제효과。재pH위3.0시，H2O2거질자화반응곤난，고O3/H2O2양화효솔겁저， H2O2농도야궤호불변。가입TiO2능명현제고H2O2적분해속솔，상비금홍석TiO2，예태광TiO2사H2O2재5 min내기본분해완필，단기대 H2O2/O3양화효솔궤호몰유영향。포화취양수분해속도적비처리실험야유상사적결과。유차가견，합괄인발제농도가능시보증취양류고급양화기술교고효솔적관건，부칙지회도치양화제적무효과쾌분해。이용록화초기사담서람법대비분석료산성조건하H2O2/O3、예태광TiO2/H2O2/O3화금홍석TiO2/H2O2/O3체계산생초양자유기(?O 2)적량，기대소순서위：H2O2/O3<금홍석TiO2/H2O2/O3<예태광TiO2/H2O2/O3，저여전면결과문합흔호。
The oxidation efficiency of H2O2/O3catalyzed by titanium dioxide (TiO2) for acetic acid (HAc) degradation, a probe compound for hydroxyl radical in ozonation, was investigated, with a focus on the effect of TiO2 crystal phase. The results indicated that the addition of TiO2showed negative effect on the oxidation efficiency when the initial pH was at 7.0 and 10.0, and among all crystal phases of TiO2 anatase had the biggest negative effect. However, when the initial pH was at 3.0, rutile could significantly improve the oxidation efficiency of the H2O2/O3 system, and anatase had negligible effect. The mechanism study showed that there existed a good correlation between degradation rate of HAc and concentration of H2O2 (or its decomposition rate). Both anatase and rutile could accelerate decomposition of H2O2 at initial pH of 7.0 and 10.0, and faster was for the former than the latter. Too high decomposition rate of H2O2 could reduce removal rate of HAc at the two pH, <br> because the conjugate base HO?2 of H2O2 generated could react with ozone to effectively produce hydroxyl radicals (?OH). At initial pH 3.0, the oxidation efficiency of H2O2/O3 system was very low due to the difficulty of H2O2deprotonation, so the concentration of H2O2 had almost no change. Addition of TiO2 could markedly accelerate the decomposition rate of H2O2, including deprotonation step, and anatase made H2O2 decomposition finish in 5 min and too fast, leading to have no effect on the oxidation efficiency. However, rutile had no such high decomposition rate for H2O2and could generate HO?2-similar species which could react with ozone to produce hydroxyl radicals (?OH) to degrade acetic acid. The batch test carried out also gave a similar result. Therefore, it can be concluded that suitable initiator and its concentration may play an important role in ozone-based advanced oxidation process, and that too high concentration of initiator might lead to rapid consumption of oxidants. The amounts of superoxide ion radical (?O?2) in H2O2/O3, anatase TiO2/H2O2/O3 and rutile TiO2/H2O2/O3 systems were determined by capturing method of Nitro Blue Tetrazolium Chloride (NBT), the order was as follows: H2O2/O3< rutile TiO2/H2O2/O3< anatase TiO2/H2O2/O3, which was in accord with the results of the results of HAc degradation.
