王 瑩,魏成耀,黃天寅,吳 瑋,陳家斌(蘇州科技大學(xué)環(huán)境科學(xué)與工程學(xué)院,江蘇 蘇州 215009)

氮摻雜碳納米管活化過一硫酸鹽降解酸性橙AO7

王 瑩,魏成耀,黃天寅,吳 瑋,陳家斌*(蘇州科技大學(xué)環(huán)境科學(xué)與工程學(xué)院,江蘇 蘇州 215009)

采用氮摻雜多壁碳納米管(N-CNT)作為固體活化劑,活化過一硫酸鹽(PMS)氧化降解偶氮染料酸性橙7(AO7).結(jié)果表明,N-CNT活化PMS降解AO7比顆?；钚蕴?GAC)效果好,N-CNT投加量為400mg/L、n(PMS)/n(AO7) 為 40/1時(shí),反應(yīng)60min可使AO7的脫色率達(dá)到99%; 研究了N-CNT活化PMS降解AO7的降解機(jī)制,發(fā)現(xiàn)N-CNT活化PMS產(chǎn)生的自由基主要是SO4-?,活化場(chǎng)所在N-CNT的表面.在N-CNT/PMS體系中,初始pH值對(duì)降解AO7有較大的影響,當(dāng)pH = 3.0時(shí)AO7降解效果最好; Cl-、SO42-和CO32-離子對(duì)AO7降解都存在一定促進(jìn)作用,離子濃度越高,AO7降解速率越快.紫外可見光譜、TOC分析表明AO7分子中偶氮鍵及萘環(huán)結(jié)構(gòu)均被破壞,并進(jìn)一步礦化為CO2和H2O.

氮摻雜碳納米管；過一硫酸鹽；酸性橙7

偶氮染料是分子結(jié)構(gòu)中含有一個(gè)或多個(gè)偶氮基(–N=N–)的染料,其生產(chǎn)廢水具有毒性強(qiáng)、含鹽量高、致突變、致癌、難降解等特點(diǎn)[1-2],不經(jīng)處理直接排放會(huì)對(duì)環(huán)境造成嚴(yán)重污染.偶氮染料廢水常用的處理方法有吸附[3]、膜過濾[4]、光催化[5-6]、臭氧化[7-8]等.

普通碳納米管(CNT)因具有比表面積大、熱穩(wěn)定性高、獨(dú)特管腔和吸附特性以及特有的電學(xué)特性等性質(zhì),已作為新型催化材料引起了人們的極大興趣,取得了廣泛的應(yīng)用,例如在其力學(xué)性能方面,CNT的強(qiáng)度比其他纖維強(qiáng)度約高 200倍,加之CNT的韌性很好,使其可以廣泛應(yīng)用于微米甚至納米機(jī)械;同時(shí),CNT還是一種新型超導(dǎo)材料,具有很高的臨界超導(dǎo)電流,這為熱敏電阻輻射器件的研制和開發(fā)提供了條件.目前,CNT的制備方法主要有石墨電弧法、激光蒸發(fā)法和催化熱解法.

當(dāng)碳納米管摻入氮(N-CNT)之后,改變了碳原子周圍的電子云密度,使其具有良好的電子傳導(dǎo)性,其電子效應(yīng)也在催化材料方面展示出獨(dú)特性能.目前,氮摻雜碳納米管的制備方法可以分為3:(1)同步原位摻雜,即在CNT生成過程中進(jìn)行摻雜; (2)高溫碳化含氮高分子; (3)在含氮條件下,對(duì)碳納米管進(jìn)行后處理,如采用等離子體、水熱等方法進(jìn)行氮摻雜.氮摻雜將影響CNT的狀態(tài)密度、微分電容、體電導(dǎo)率和功函數(shù)等電化學(xué)及電子性質(zhì),使得碳納米管可實(shí)現(xiàn)較低電位下氧的吸附解離,從而具有氧化還原反應(yīng)催化活性.

碳納米管具有獨(dú)特的電學(xué),機(jī)械和結(jié)構(gòu)性能.由于氮和碳的原子半徑相差不多,所以在六邊形石墨網(wǎng)狀結(jié)構(gòu)的碳納米管中經(jīng)常用氮原子來取代碳原子以改變碳納米管的電學(xué)和化學(xué)性能,從而使碳納米管具有某些特殊功用,如催化載體,傳感器和碳極等.在催化劑載體研究領(lǐng)域,科學(xué)家們發(fā)現(xiàn)碳納米管中的氮摻雜原子本身還具有氧還原催化活性,從而使非貴金屬負(fù)載的 N-CNT作為催化材料的研發(fā)備受關(guān)注.本文采用 N-CNT活化 PMS降解 AO7,分析其降解過程; 研究了AO7降解的主要影響因素(N-CNT投加量、PMS濃度、初始pH值、溫度、離子濃度),并對(duì)各反應(yīng)條件對(duì)降解反應(yīng)進(jìn)行分析.

1 材料與方法

1.1 材料

實(shí)驗(yàn)用氮摻雜多壁碳納米管(N-CNT)主要特性為:外直徑 30～50nm,長(zhǎng)度 10～30um,氮含量2.98wt%,比表面積＞78.9m2/g,購(gòu)于南京先豐納米材料科技有限公司;過一硫酸鹽(HKSO5· 0.5KHSO4· 0.5K2SO4,PMS)購(gòu)于Sigma-Aldrich;酸性橙 7(AO7)購(gòu)于國(guó)藥集團(tuán)化學(xué)試劑有限公司,苯酚(phenol)、甲醇(CH3OH)、叔丁醇(C4H9OH)、鹽酸(HCl)、硫酸(H2SO4)、氯化鈉(NaCl)均為分析純購(gòu)于國(guó)藥集團(tuán)化學(xué)試劑有限公司.實(shí)驗(yàn)用水為去離子超純水.

1.2 降解實(shí)驗(yàn)

在一定的溫度下,將250mL配好的AO7溶液注入錐形瓶,錐形瓶采用磁力攪拌器混合.加入一定量的PMS,用稀H2SO4或NaOH調(diào)節(jié)pH值,然后迅速加入一定量的 N-CNT啟動(dòng)反應(yīng),每隔一段時(shí)間取樣且樣品經(jīng) 0.45μm濾膜過濾后,立即測(cè)定.

1.3 分析方法

使用Mapada UV-1600(PC)紫外可見分光光度計(jì),于AO7最大吸收波長(zhǎng)484nm處測(cè)定濾液的吸光度,帶入標(biāo)準(zhǔn)曲線求得濃度c; AO7礦化率采用總有機(jī)碳分析儀(TOC-LCPH,島津)測(cè)定; 傅立葉紅外光譜分析儀(FTIR,美國(guó) Thermo公司, Nicole-6700型號(hào))測(cè)定N-CNT表面活性官能團(tuán); Quanta FEG 250掃描電子顯微鏡(美國(guó)FEI公司)測(cè)定碳納米管表面形貌特征.

2 結(jié)果與討論

2.1 FT-IR以及表面形貌分析

圖1 N-CNT催化前后的FT-IR圖譜(a)活化反應(yīng)前;(b)活化反應(yīng)后Fig.1 FT-IR spectra of the N-CNT: (a) before the catalysis; (b) after the catalysis

氮摻雜多壁碳納米管在催化反應(yīng)前后的FT-IR譜圖如圖1所示:3430cm-1處為O–H伸縮振動(dòng)吸收峰[24];在 2917cm-1處的吸收峰為-CH3、-CH2的對(duì)稱和反對(duì)稱振動(dòng)峰;2310cm-1附近對(duì)應(yīng)–C≡C–的累積雙鍵伸縮振動(dòng)區(qū); 1630cm-1附近的吸收峰是N-CNT表面羧基及內(nèi)酯基中的C=O特征伸縮振動(dòng)峰;1170cm-1處可歸于CH2–O–CH2中的C–O對(duì)稱伸縮振動(dòng)峰[25].從圖2中可以看出,N-CNT表面有大量活性官能團(tuán),且經(jīng)過活化反應(yīng)后N-CNT表面在2310處振動(dòng)峰有明顯增大,證明可能是碳質(zhì)材料表面的含氧酸性官能團(tuán)活化過一硫酸鹽[19]降解AO7.

圖 2為原始碳納米管和氮摻雜碳納米管的掃描電鏡照片.通過與原始碳納米管的形貌比較可以看出,經(jīng)含氮有機(jī)物處理后的碳納米管的形貌并未發(fā)生明顯的變化,即基本保持了原有的形貌特征,而不像強(qiáng)酸(如硝酸)、強(qiáng)堿(如強(qiáng)氧化鉀)或強(qiáng)氧化型物質(zhì)(如高錳酸鉀)等處理時(shí)發(fā)生碳納米管被切短、刻蝕而導(dǎo)致碳納米管本征形貌和結(jié)構(gòu)被破壞的現(xiàn)象[21].

圖2 CNT和N-CNT掃描電鏡照片F(xiàn)ig.2 SEM images of as-prepared CNT (a) and N-CNT (b)

2.2 N-CNT活化性能

圖3顯示了AO7在不同反應(yīng)體系中的降解效果.從中可看出,在 60min內(nèi),PMS單獨(dú)氧化體系脫色率僅為2%,同時(shí)GAC和N-CNT對(duì)AO7的吸附效果也不明顯,脫色率分別為 27.5%和17.9%,在 PMS/GAC體系中AO7的脫色率可達(dá)48.3%,然而在N-CNT/PMS體系中AO7的脫色率可達(dá)到 97%.由此得出,PMS單獨(dú)氧化降解AO7速率較低,GAC和N-CNT對(duì)AO7的吸附作用也不明顯,但N-CNT/PMS體系能夠高效氧化降解 AO7,其效果遠(yuǎn)優(yōu)于 PMS/GAC體系. Zhang[26]等曾報(bào)道GAC可以活化PMS產(chǎn)生?氧化降解染料 AO7,由此可認(rèn)為,N-CNT活化PMS產(chǎn)生SO－4?的效率要比GAC強(qiáng)的多,更利于偶氮染料AO7的氧化降解.

圖3 不同體系A(chǔ)O7的降解效果Fig.3 Degradation of AO7 in different systems

2.3 N-CNT活化機(jī)理

圖4 N-CNT/PMS體系中不同的自由基抑制劑對(duì)AO7的降解Fig.4 Degradation of AO7in the N-CNT/PMS system inthe presence of different radical scavengers

2.4 N-CNT投加量的影響

圖5 N-CNT投加量對(duì)AO7降解的影響Fig.5 Effect of N-CNT dosage on the removal of AO7

N-CNT投加量對(duì)降解AO7的效果如圖5所示.固定PMS投加量為40mg/L,60min時(shí)N-CNT對(duì)AO7吸附了1.6%,在加入一定量PMS之后,相同濃度下的N-CNT降解AO7達(dá)到31.3%;投加量增加至 200mg/L時(shí),PMS/N-CNT系統(tǒng)內(nèi)AO7在60min 時(shí)完全降解; 繼續(xù)增大投加量為400mg/L時(shí),AO7在20min就可完全降解.主要原因是N-CNT用量增加,提供了更多的活化點(diǎn)位,活化效果增強(qiáng);同時(shí)由于N-CNT的用量的增加,對(duì)染料AO7的吸附量也略微提高.

2.5 PMS濃度的影響

圖6為不同PMS濃度對(duì)AO7降解的影響.可以看出,與N-CNT用量對(duì)AO7降解的影響相似,隨PMS濃度的增大,AO7降解速度越快,降解完全所需時(shí)間越短.當(dāng)n(PMS):n(AO7)為10:1時(shí),反應(yīng)至 60min時(shí) AO7僅降解 59.5%; 然而當(dāng)n(PMS): n(AO7)為20:1、40:1時(shí),反應(yīng)至60min時(shí) AO7分別降解了 81.4%和 97.3%.繼續(xù)增大PMS用量至n(PMS): n(AO7)= 80:1,AO7降解至99%以上僅需30min.有研究認(rèn)為,當(dāng)PMS濃度過高時(shí),自由基相互反應(yīng),產(chǎn)生氧化能力較弱的 SO—5·等[見式(1) ～ (2)].因此PMS濃度應(yīng)控制在適當(dāng)范圍,后續(xù)實(shí)驗(yàn)選取n(PMS): n(AO7)為40:1.

圖6 PMS濃度對(duì)AO7降解的影響Fig.6 Effect of PMS concentration on the removal of AO7

2.6 pH值的影響

圖7顯示了不同初始pH值對(duì)反應(yīng)活化體系降解AO7的影響.從中可知,在pH值為3時(shí)反應(yīng)速率最快,且隨著pH值的增大,在pH值分別為5、7、9時(shí),反應(yīng)速率逐漸降低.這一現(xiàn)象可能與N-CNT的表面零電荷點(diǎn)有關(guān).當(dāng)溶液 pH＜pHpzc時(shí),N-CNT表面帶正電荷,有利于陰離子染料吸附;當(dāng)溶液pH ＞ pHpzc時(shí),N-CNT表面帶負(fù)電荷,有利于陽離子染料的吸附[19].經(jīng)測(cè)得 N-CNT的pHpzc為 4.4,所以當(dāng)溶液 pH值分別為 5、7、9時(shí),N-CNT表面帶負(fù)電荷.由于AO7屬于陰離子偶氮染料,導(dǎo)致AO7與N-CNT的表面產(chǎn)生相互排斥的效果,使得表面反應(yīng)不容易進(jìn)行;同時(shí),在堿性條件下,SO—4·易轉(zhuǎn)化為HO·,且HO·會(huì)與OH—反應(yīng)使氧化劑淬滅[見式(3)～(4)].

圖7 初始pH值對(duì)AO7降解的影響Fig.7 Effect of initial pH on the removal of AO7

2.7 溫度變化的影響

溫度通常是活化反應(yīng)中的關(guān)鍵因素,如圖8(a)所示,考察了不同溫度條件下活化降解 AO7效果.可以看出,PMS單獨(dú)活化降解AO7受溫度影響較小,在60℃下反應(yīng)60min時(shí),AO7降解率僅為5.5%;而N-CNT活化PMS降解AO7,隨反應(yīng)體系溫度升高,降解速率加快.當(dāng)在 50℃時(shí),NCNT活化降解AO7在20min時(shí)降解率可達(dá)到99.5%,而當(dāng)在60℃時(shí),AO7降解完全僅需15min.這可能是因?yàn)樵诟邷貤l件下 N-CNT更易活化PMS產(chǎn)生,并且染料分子在高溫下容易克服反應(yīng)活化能.由圖 8(b)可知,在不同溫度條件下,N-CNT/PMS體系降解AO7符合一級(jí)降解動(dòng)力學(xué),反應(yīng)速率常數(shù)k隨溫度升高逐漸變大,表明隨溫度升高,降解速率加快;并通過 Arrhenius公式計(jì)算出反應(yīng)活化能Ea為69.7kJ/mol.

圖8 反應(yīng)溫度對(duì)AO7降解的影響以及一級(jí)降解動(dòng)力學(xué)與Arrhenius擬合Fig.8 Effect of reaction temperature on AO7 degradation and first order kinetics model and Arrhenius plot

2.8 NaCl、Na2SO4和Na2CO3對(duì)反應(yīng)的影響

印染工藝中往往通過投加 NaCl加速染色,導(dǎo)致其產(chǎn)生廢水通常含有大量的 NaCl,然而 Cl-對(duì)高級(jí)氧化過程有較大影響.圖9顯示了不同濃度NaCl對(duì)活化降解AO7的影響.可以看出,加入Cl-會(huì)促進(jìn) AO7的降解,且隨著 Cl-濃度的增加,AO7降解速率增大.當(dāng)Cl-濃度為10mmol/L時(shí),反應(yīng)在 30min時(shí)降解 99%;當(dāng) Cl-濃度達(dá)到100mmol/L時(shí),AO7在 10min時(shí)已經(jīng)降解完全.以上實(shí)驗(yàn)結(jié)果的原因可能是,當(dāng)NaCl存在時(shí),Cl-與反應(yīng)生成具有強(qiáng)氧化性的 HClO[見式(5)～(9)].在?和ClO-共同作用下,AO7降解速率明顯提高.

圖9 NaCl濃度對(duì)AO7降解的影響Fig.9 Effect of NaCl amounts on AO7 removal

圖10 Na2SO4和Na2CO3濃度對(duì)AO7降解的影響Fig.10 Effect of Na2SO4and Na2CO3amounts on AO7 removal

染料廢水中除 NaCl濃度較高之外,通常以硫酸鈉、碳酸鈉等作為直接染料而導(dǎo)致染料廢水中大量的存在.從圖10可以看出隨著濃度的升高,反應(yīng)體系中AO7降解速率增大.這可能是因?yàn)楦邼舛鹊暮涂梢栽鰪?qiáng)離子強(qiáng)度,從而導(dǎo)致染料分子之間相互聚合,染料分子團(tuán)聚后,更容易吸附于 NCNT表面,從而有利于染料和表面活性自由基的反應(yīng),促進(jìn)AO7氧化脫色.

2.9 降解分析

圖11 AO7降解紫外可見光譜及TOC去除率Fig.11 UV-Vis spectra for degradation of AO7 (a) and TOC removal in N-CNT/PMS systems (b)

圖11(a)所示為N-CNT/PMS體系降解AO7過程中紫外可見光譜.可以看出,AO7主要有484nm和310nm處的特征吸收峰,分別代表AO7的發(fā)色基團(tuán)偶氮鍵和萘環(huán)結(jié)構(gòu).隨活化反應(yīng)的進(jìn)行,位于484nm和310nm處的AO7特征峰強(qiáng)度不斷下降,表明AO7的偶氮鍵和萘環(huán)結(jié)構(gòu)不斷被?氧化;60min后,偶氮鍵和萘環(huán)的特征峰接近消失.

為了進(jìn)一步研究各 N-CNT/PMS體系降解AO7的TOC變化情況,本次研究還對(duì)反應(yīng)過程中的TOC進(jìn)行了測(cè)試,如圖11(b)所示,對(duì)N-CNT體系,在0、20、40、60min分別取樣,它們對(duì)AO7吸附效果的 TOC去除率分別為 0%、14.8%、15.1%和15.3%;而對(duì)于N-CNT/PMS體系中,在0、20、40、60min分別取樣,它們對(duì)AO7的TOC去除率分別為 0%、19.6%、20%和 20.4%.結(jié)果表明N-CNT/PMS體系對(duì)AO7不僅有良好的降解效果,而且具有一定的礦化能力.

3 結(jié)論

3.1 N-CNT活化PMS降解AO7效果良好,可以證實(shí)CNT活化PMS產(chǎn)生的自由基主要是SO4-?, PMS被活化的場(chǎng)所在N-CNT的表面.

3.2 AO7降解效果隨N-CNT投加量、PMS濃度、溫度、Cl-等離子濃度的增大而得到提高.初始 pH值對(duì)降解有較大的影響,偏酸性條件下更有利于反應(yīng)進(jìn)行.

3.3 N-CNT/PMS體系對(duì)AO7的脫色效果良好,且N-CNT/PMS體系能使AO7分子得到一定程度的礦化.

[1] Ji P, Zhang J, Chen F, et al. Study of adsorption and degradation of acid orange 7 on the surface of CeO2under visible light irradiation [J]. Applied Catalysis B: Environmental, 2009, 85(3/4):148-154.

[2] Xu X, Li X. Degradation of azo dye Orange G in aqueous solutions by persulfate with ferrous ion [J]. Separation and Purification Technology, 2010,72(1):105-111.

[3] Gupta V K, Gupta B, Rastogi A, et al. A comparative investigation on adsorption performances of mesoporous activated carbon prepared from waste rubber tire and activated carbon for a hazardous azo dye—Acid Blue 113 [J]. Journal of Hazardous Materials, 2011,186(1):891-901.

[4] Anipsitakis G P, Dionysiou D D. Degradation of Organic Contaminants in Water with Sulfate Radicals Generated by theConjunction of Peroxymonosulfate with Cobalt [J]. Environmental Science & Technology, 2003,37(20):4790-4797.

[5] Saleh T A, Gupta V K. Photo-catalyzed degradation of hazardous dye methyl orange by use of a composite catalyst consisting of multi-walled carbon nanotubes and titanium dioxide [J]. Journal of Colloid and Interface Science, 2012,371(1):101-106.

[6] Khataee A R, Pons M N, Zahraa O. Photocatalytic degradation of three azo dyes using immobilized TiO2nanoparticles on glass plates activated by UV light irradiation: Influence of dye molecular structure [J]. Journal of Hazardous Materials, 2009, 168(1):451-457.

[7] Cuiping B, Xianfeng X, Wenqi G, et al. Removal of rhodamine B by ozone-based advanced oxidation process [J]. Desalination, 2011,278(1-3):84-90.

[8] Faria P C C, órf?o J J M, Pereira M F R. Activated carbon and ceria catalysts applied to the catalytic ozonation of dyes and textile effluents [J]. Applied Catalysis B: Environmental, 2009, 88(3/4):341-350.

[9] 陳家斌,魏成耀,房 聰,等.碳納米管活化過二硫酸鹽降解偶氮染料酸性橙7 [J]. 中國(guó)環(huán)境科學(xué), 2016,36(12):3618-3624.

[10] 張黎明,陳家斌,房 聰,等.Cl-對(duì)碳納米管/過一硫酸鹽體系降解金橙G的影響 [J]. 中國(guó)環(huán)境科學(xué), 2016,36(12):3591-3600.

[11] Yang S, Yang X, Shao X, et al. Activated carbon catalyzed persulfate oxidation of Azo dye acid orange 7 at ambient temperature [J]. Journal of Hazardous Materials, 2011,186(1): 659-666.

[12] Waldemer R H, Tratnyek P G, Johnson R L, et al. Oxidation of Chlorinated Ethenes by Heat-Activated Persulfate: Kinetics and Products [J]. Environmental Science & Technology, 2007,41(3): 1010-1015.

[13] Liang C, Bruell C J. Thermally Activated Persulfate Oxidation of Trichloroethylene: Experimental Investigation of Reaction Orders [J]. Industrial & Engineering Chemistry Research, 2008,47(9): 2912-2918.

[14] Ghauch A, Tuqan A M, Kibbi N, et al. Methylene blue discoloration by heated persulfate in aqueous solution [J]. Chemical Engineering Journal, 2012,213:259-271.

[15] Gao Y, Gao N, Deng Y, et al. Ultraviolet (UV) light-activated persulfate oxidation of sulfamethazine in water [J]. Chemical Engineering Journal, 2012,195-196:248-253.

[16] He X, de la Cruz A A, Dionysiou D D. Destruction of cyanobacterial toxin cylindrospermopsin by hydroxyl radicals and sulfate radicals using UV-254nm activation of hydrogen peroxide, persulfate and peroxymonosulfate [J]. Journal of Photochemistry and Photobiology A: Chemistry, 2013,251:160-166.

[17] Kusic H, Peternel I, Ukic S, et al. Modeling of iron activated persulfate oxidation treating reactive azo dye in water matrix [J]. Chemical Engineering Journal, 2011,172(1):109-121.

[18] Rodriguez S, Vasquez L, Costa D, et al. Oxidation of Orange G by persulfate activated by Fe(II), Fe(III) and zero valent iron (ZVI) [J]. Chemosphere, 2014,101:86-92.

[19] Yang S, Xiao T, Zhang J, et al. Activated carbon fiber as heterogeneous catalyst of peroxymonosulfate activation for efficient degradation of Acid Orange 7in aqueous solution [J]. Separation and Purification Technology, 2015,143:19-26.

[20] Oh W, Lua S, Dong Z, et al. Performance of magnetic activated carbon composite as peroxymonosulfate activator and regenerable adsorbent via sulfate radical-mediated oxidation processes [J]. Journal of Hazardous Materials, 2015,284:1-9.

[21] Lee Y, Lo S, Kuo J, et al. Promoted degradation of perfluorooctanic acid by persulfate when adding activated carbon [J]. Journal of Hazardous Materials, 2013,261:463-469.

[22] O'Reilly J M, Mosher R A. Functional groups in carbon black by FTIR spectroscopy [J]. Carbon, 1983,1(21):47-51.

[23] Sun X, Li Y. Colloidal Carbon Spheres and Their Core/Shell Structures with Noble-Metal Nanoparticles [J]. Angewandte Chemie International Edition, 2004,43(5):597-601.

[24] Fierro V, Torné-Fernández V, Celzard A, et al. Influence of the demineralisation on the chemical activation of Kraft lignin with orthophosphoric acid [J]. Journal of Hazardous Materials, 2007, 149(1):126-133.

[25] 李莉香,劉永長(zhǎng),耿 新,等.氮摻雜碳納米管的制備及其電化學(xué)性能 [J]. 物理化學(xué)學(xué)報(bào), 2011,27(2):443-448.

[26] Zhang J, Shao X, Shi C, et al. Decolorization of Acid Orange 7with peroxymonosulfate oxidation catalyzed by granular activated carbon [J]. Chemical Engineering Journal, 2013,232: 259-265.

致謝：本實(shí)驗(yàn)的表征測(cè)量等工作由江蘇省環(huán)境科學(xué)與工程重點(diǎn)實(shí)驗(yàn)室協(xié)助完成,在此表示感謝.

Activation of peroxymonosulfate by nitrogen-doped carbon nanotubes to decolorize acid orange 7.

WANG Ying, WEI Cheng-yao, HUANG Tian-yin, WU Wei, CHEN Jia-bin*(School of Environmental Science and Engineering, Suzhou University of Science and Technology, Suzhou 215009, China). China Environmental Science, 2017,37(7)：2583～2590

Nitrogen-doped carbon nanotube (N-CNT) was used as an activator to activate peroxymonosulfate (PMS) to degrade azo dye, Acid orange 7 (AO7) in aqueous solution. The results indicated that N-CNT exhibited a much better performance on activating PMS to decolorize AO7 than activated carbon (GAC), the removal of AO7 could reach 99% after 60min with 400mg/L of N-CNT dosage, 40/1of PMS/AO7 molar ratio. The degradation mechanism of AO7 in N-CNT activated PMS system was explored,and SO－4? was found to be dominantly responsible for AO7 degradation, which mainly took place on the surface of N-CNT. The The initial pH had a significant effect on the AO7 degradation, and pH 3.0 was most favorable for its degradation. In addition, the degradation of AO7 was accelerated after addition of Cl-、SO2-4and CO2-3; From the analysis of UV-vis spectra and TOC analysis indicated that the azo band and naphthaline ring of AO7 that were destructed and then mineralized into CO2and H2O.

nitrogen-doped carbon nanotubes；peroxymonosulfate；acid orange 7

X703,X131.2

A

1000-6923(2017)07-2583-08

王 瑩(1993-),女,黑龍江七臺(tái)河人,碩士研究生,主要從事污水處理研究.

2016-12-19

國(guó)家自然科學(xué)基金資助項(xiàng)目(51478283);蘇州科技大學(xué)大學(xué)生創(chuàng)新訓(xùn)練計(jì)劃項(xiàng)目(201613985007Y)

* 責(zé)任作者, 講師, chenjiabincn@163.com