本文關(guān)鍵詞：高級(jí)氧化法降解呋蟲胺的研究　出處：《河南師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 呋蟲胺 降解 Fenton 過硫酸鉀 高級(jí)氧化

【摘要】：呋蟲胺(dinotefuran),化學(xué)名稱:(RS)-1-甲基-2-硝基-3-[(3-四氫呋喃)甲基]胍,是一種新型的煙堿類殺蟲劑,因其具備眾多優(yōu)點(diǎn)而逐漸被人們熟知,有望成為全世界廣泛使用的農(nóng)藥。本文分別采用4種不同的高級(jí)氧化方法降解呋蟲胺,考察了呋蟲胺在不同氧化方式下的降解情況,研究了不同因素對(duì)呋蟲胺降解的影響,并推測其氧化降解機(jī)理。Fenton法降解呋蟲胺的實(shí)驗(yàn)考察了不同p H條件和不同溫度對(duì)呋蟲胺降解的影響,結(jié)果表明:在溫度一定的條件下,p H對(duì)呋蟲胺降解的影響較大,當(dāng)初始p H為3時(shí)最利于呋蟲胺的降解,p H的升高或降低均不利于呋蟲胺的降解;在初始p H一定的條件下,呋蟲胺的降解率隨著溫度的升高而增加,但是增加幅度并不大,溫度從15℃升到30℃,呋蟲胺的降解率僅提高了5.38%。在溫度和p H一定的條件下,通過添加不同濃度的H2O2,考察了氧化劑的量對(duì)于Fenton法降解呋蟲胺的影響,結(jié)果表明當(dāng)呋蟲胺濃度為100 mg/L時(shí),H2O2的最佳投加濃度為0.2 mol/L,氧化劑的濃度過高或過低均不利于呋蟲胺的降解;在反應(yīng)的溫度、初始p H和氧化劑的量均一定的條件下,通過改變?nèi)芤褐蠪e2+的濃度,考察了不同濃度的催化劑對(duì)呋蟲胺降解的影響,結(jié)果表明當(dāng)呋蟲胺的濃度為100 mg/L、H2O2的投加濃度為0.2 mol/L時(shí),Fe2+的最佳濃度為0.06 mmol/L。對(duì)呋蟲胺在不同條件下的降解情況進(jìn)行動(dòng)力學(xué)擬合分析,可知Fenton法降解呋蟲胺的反應(yīng)符合二級(jí)動(dòng)力學(xué)規(guī)律。通過高效液相色譜和質(zhì)譜聯(lián)用技術(shù)(HPLC-MS)對(duì)產(chǎn)物進(jìn)行分離鑒定,可知呋蟲胺只有一種降解產(chǎn)物,可能為1-甲基-3-(四氫-3-呋喃甲基)脲。Fenton法聯(lián)合光照降解呋蟲胺的實(shí)驗(yàn)考察了溫度、p H、氧化劑的量及催化劑的量等因素對(duì)呋蟲胺降解的影響,鑒于目前實(shí)際工程中的廢水處理大多以COD為檢測標(biāo)準(zhǔn),故本節(jié)實(shí)驗(yàn)以COD的降解率為指標(biāo)。實(shí)驗(yàn)結(jié)果表明,當(dāng)呋蟲胺的初始濃度為200 mg/L時(shí),光照聯(lián)合Fenton降解呋蟲胺的最佳條件為:溫度30℃,p H為3.0,Fe2+濃度為0.2mmol/L,H2O2的濃度為32 mmol/L。H2O2投加方式也對(duì)Fenton法降解呋蟲胺的過程有影響,實(shí)驗(yàn)結(jié)果表明當(dāng)總投加量一定時(shí),采用分批次投加且先多量后少量的投加方式更利于COD的降解。超聲聯(lián)合Fenton法考察了不同頻率的超聲波對(duì)COD降解的影響,結(jié)果表明低頻率超聲促進(jìn)COD的降解,高頻率超聲反而抑制COD的降解。熱活化過硫酸鉀降解呋蟲胺的實(shí)驗(yàn)結(jié)果表明,溫度越高,呋蟲胺的降解速率越快,通過對(duì)呋蟲胺降解的情況進(jìn)行動(dòng)力學(xué)擬合分析,發(fā)現(xiàn)熱活化過硫酸鉀降解呋蟲胺的過程符合一級(jí)動(dòng)力學(xué)規(guī)律,當(dāng)溫度為40、50、60、70、80℃時(shí),呋蟲胺降解的半衰期分別為1732、990、173、22、7 min,通過阿倫尼烏斯方程得過硫酸鉀降解呋蟲胺的活化能為133.498 k J/mol。通過調(diào)節(jié)不同的初始p H,可知p H對(duì)過硫酸鉀降解呋蟲胺的影響較小,中性條件下可達(dá)最高降解率僅比堿性條件下達(dá)到的最低降解率高了6.05%。過硫酸鉀的濃度對(duì)于呋蟲胺的降解影響較大,在溫度一定時(shí)(70℃),過硫酸鉀濃度為2、4、6、8、10、25、50 mmol/L,呋蟲胺的降解半衰期分別為173、90、77、45、28、9、6 min。Cl-和HCO3-對(duì)反應(yīng)的影響較為復(fù)雜,當(dāng)溶液中的Cl-濃度和HCO3-濃度較低時(shí),均能夠促進(jìn)呋蟲胺的降解,當(dāng)其濃度超過某拐點(diǎn)濃度時(shí)呋蟲胺的降解則逐漸受到抑制。超聲的存在能夠明顯促進(jìn)呋蟲胺的降解。通過添加自由基捕獲劑探究其降解機(jī)理,結(jié)果表明,該反應(yīng)體系中同時(shí)存在著硫酸根自由基·SO4-和羥基自由基·OH,兩種自由基均參與了呋蟲胺的降解,且起主要作用的為·SO4-。
[Abstract]:Dinotefuran (dinotefuran), chemical name: (RS) -1- methyl -2- nitro -3-[(3- tetrahydrofuran) methyl] guanidine, is a new type of neonicotinoid insecticides, because it has many advantages and have been gradually known, is expected to become widely used pesticides in the world. This paper uses 4 kinds of advanced oxidation method different degradation dinotefuran, investigated the degradation of dinotefuran in different oxidation conditions, the effects of different factors on the degradation of dinotefuran, and speculated that the degradation mechanism of.Fenton degradation by dinotefuran studied P H, different conditions and different temperature on the degradation of dinotefuran the results show that under certain temperature condition, effect of P H on dinotefuran degradation is larger, the initial P H 3 the degradation most beneficial to dinotefuran, degradation of P H increased or decreased was not conducive to dinotefuran; in the initial P H, degradation of furosemide worm amine The rate increases with the increase of temperature, but the increase is not large, the temperature from 15 DEG C to 30 DEG C, the degradation rate of only dinotefuran increased 5.38%. in temperature and P H under certain conditions by adding different concentrations of H2O2, the effects of the amount of oxidant for Fenton degradation of dinotefuran the results show that when the dinotefuran concentration was 100 mg/L, H2O2 dosage was 0.2 mol/L and the concentration of oxidant concentration was too high or too low is not conducive to the degradation of dinotefuran; in the reaction temperature, the initial P H and oxidant amount under certain conditions by changing the concentration of solution in Fe2+, we investigated the effect of different concentration of dinotefuran degradation, the results showed that when the dinotefuran was 100 mg/L, H2O2 dosage is 0.2 mol/L, the optimal concentration of Fe2+ was 0.06 mmol/L. for the kinetics of degradation of dinotefuran under different conditions Analysis shows that Fenton degradation of dinotefuran reaction with two order kinetics. By high performance liquid chromatography and mass spectrometry (HPLC-MS) and the products were separated and identified, the dinotefuran is only one possible degradation products, 1- methyl -3- (four h -3- methylfuran) urea.Fenton method combined with light the degradation of dinotefuran experiments the effects of temperature, P H, factors affecting the amount of oxidant and catalyst amount on dinotefuran degradation, in view of the current wastewater treatment engineering are based on COD standards, and therefore the experiment with the degradation rate of COD as index. The experimental results show that when the initial the concentration of dinotefuran was 200 mg/L, the best light conditions combined with Fenton degradation dinotefuran: temperature 30, P H 3, Fe2+ concentration is 0.2mmol/L, the concentration of H2O2 was affected 32 mmol/L.H2O2 dosing mode also process of Fenton degradation by dinotefuran, experiments. Results show that when the total dosage when using batches and the first volume and degradation of investment after a small amount of adding more favorable COD. Ultrasound combined with Fenton to investigate the effect of different frequency ultrasonic on COD degradation. The results show that the degradation of low frequency ultrasound to promote the COD degradation of high frequency ultrasonic inhibited COD. The activation of potassium persulfate degradation dinotefuran. The experimental results show that the higher the temperature, the degradation rate of dinotefuran faster, the dynamic fitting through the analysis of the dinotefuran degradation, found that the thermal activation process of potassium sulfate degradation dinotefuran accord with first-order kinetics when the temperature 40,50,60,70,80 C, dinotefuran degradation half-life of 1732990173,22,7 min respectively, through the Arrhenius equation to activation of potassium sulfate degradation dinotefuran to 133.498 K J/mol. by adjusting the different initial P H, P H of persulfate The smaller effect of potassium degradation dinotefuran, minimum degradation under neutral conditions can reach the highest degradation rate than under alkaline conditions reached the rate of high concentration of 6.05%. potassium persulfate for degradation of dinotefuran influence, in a certain temperature (70 DEG C), potassium persulfate concentration was 2,4,6,8,10,25,50 mmol/L, the degradation half-life of furosemide. Amine were unaffected by 173,90,77,45,28,9,6 min.Cl- and HCO3- on the reaction is more complex, when the concentration of Cl- and HCO3- concentration in the solution is low, can promote the degradation of dinotefuran, when the concentration exceeds a certain inflection point when the concentration of degradation dinotefuran is gradually suppressed. The presence of ultrasound can significantly promote the degradation of furosemide. Amine. By adding free radical scavenger on the degradation mechanism, the results show that the exist of the reaction system with sulfate radical and hydroxyl radical - SO4- - OH, two free radicals are involved in the dinotefuran Degradation, and the main effect is. SO4-.

【學(xué)位授予單位】：河南師范大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X592

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本文編號(hào)：1358653