CP/PVDF膜電活化PS降解新污染物及緩解膜污染

劉 寅,許岐斌,宋子恒,劉 索,趙 純

CP/PVDF膜電活化PS降解新污染物及緩解膜污染

劉 寅,許岐斌,宋子恒,劉 索,趙 純*

(重慶大學(xué),三峽庫區(qū)生態(tài)環(huán)境教育部重點實驗室,重慶 400045)

通過耦合高級氧化技術(shù)實現(xiàn)超濾過程中對膜污染的緩解以及小分子溶解性有機污染物(SMOP)的去除.通過噴涂的方式將交聯(lián)聚吡咯的碳納米管沉積在聚偏氟乙烯(PVDF)膜表面,得到了具有優(yōu)異導(dǎo)電性的交聯(lián)聚吡咯的碳納米管復(fù)合超濾膜(CP/PVDF).實驗中建立了膜陰極過濾過硫酸鹽體系(E-PS-CP/PVDF).并比較了過一硫酸鹽(PMS)和過二硫酸鹽(PDS)分別作為氧化劑時該體系對膜污染的緩解(HA作為模擬污染物)以及小分子有機物的去除效果.結(jié)果表明,E-PS-CP/PVDF體系對3種小分子有機污染物(SMOP)卡馬西平(CBZ)、雙氯芬酸鈉(DCF)和磺胺甲噁唑(SMX)均有較高的去除速率,其一級動力學(xué)常數(shù)均高于15×10-2min-1遠高于單獨超濾體系(最高為0.072×10-2min-1).E-PS-CP/PVDF體系具有明顯的膜污染緩解作用,使用PMS和PDS作為電解質(zhì)時,60min內(nèi)出水比通量僅僅分別下降到0.93和0.84,外加電場與活性物質(zhì)對HA的氧化作用改變了污染物在膜表面的相互作用,減少了HA在膜上的沉積.此外,通過捕獲實驗探究了E-PS-CP/PVDF體系緩解膜污染的機理.,E-PS-CP/PVDF體系中緩解膜污染的主要原因是由于體系中的PS被膜陰極活化產(chǎn)生了?OH 、SO4?-和1O2,且PMS作為氧化劑具有更好的表現(xiàn).因此,E-PS-CP/PVDF體系能夠?qū)崿F(xiàn)超濾過程中膜污染的緩解和對小分子有機物的去除,在實際水處理領(lǐng)域具有良好的應(yīng)用前景.

PVDF；CP/PVDF膜；過硫酸鹽；電活化；腐殖酸

超濾膜(UF)是一種介于微濾和納濾之間的低壓膜,由于其具有良好的透水性、穩(wěn)定性以及對大分子污染物的有效截留而越來越被研究學(xué)者所關(guān)注[1].但小分子溶解性有機污染物(SMOP)截留效果差以及膜污染嚴重的問題一直是限制超濾技術(shù)發(fā)展的阻礙[2-3].混凝和吸附等預(yù)處理工藝難以有效解決上述兩個問題.

高級氧化技術(shù)憑借能產(chǎn)生較強的活性物質(zhì)而受到了研究學(xué)者的重視.與?OH基高級氧化技術(shù)相比,SO4?-基高級氧化技術(shù)具有氧化還原電位高(E0=2.5～3.1e V)以半衰期長(30～40us)等優(yōu)點[4-5].因此,通過聯(lián)用SO4?-基高級氧化技術(shù)在超濾膜處理工藝中的應(yīng)用受到了廣泛關(guān)注[6].

目前耦合過硫酸鹽高級氧化的膜過濾技術(shù)主要是通過膜改性方式制備催化膜,從而實現(xiàn)對過硫酸鹽的活化.其中過渡金屬對過硫酸鹽具有很好的活化表現(xiàn),但是過渡金屬的引入會產(chǎn)生金屬泄露問題[7–10].相較于過渡金屬,碳基材料活化過硫酸鹽更加經(jīng)濟環(huán)保[11-12].然而碳材料活化過硫酸鹽的過程中,過硫酸鹽以及原位產(chǎn)生的活性物質(zhì),會破壞碳基材料的表面結(jié)構(gòu)和官能團[12-13].陰極電場可以將自由電子傳遞到碳材料的表面用于活化過硫酸鹽,使碳材料在活化過程中的作用從電子供體轉(zhuǎn)變?yōu)殡姶呋牧?以增強其在長期循環(huán)催化能力,保護其表面結(jié)構(gòu)和官能團.然而,對于電活化過硫酸鹽與超濾技術(shù)相結(jié)合的研究十分有限.因此,對耦合電活化過硫酸鹽的超濾技術(shù)在緩解膜污染方面的表現(xiàn)及機理值得深入探究.

相比較于其他超濾膜材料,聚偏氟乙烯超濾膜(PVDF)因具有制備簡單、穩(wěn)定的理化性質(zhì)以及機械強度高等優(yōu)點被廣泛應(yīng)用于飲用水處理領(lǐng)域中[14-16].因此本文通過噴涂的方法將交聯(lián)聚吡咯的碳納米管沉積在PVDF膜表面,成功制備了具有優(yōu)異導(dǎo)電性的復(fù)合超濾膜CP/PVDF,建立了膜陰極活化過硫酸鹽過濾體系.通過對負載交聯(lián)聚吡咯的碳納米管后的超濾膜形貌結(jié)構(gòu)、親水性、導(dǎo)電性以及穩(wěn)定性的表征,確定了復(fù)合膜的成功制備.探究了E-PS-CP/PVDF體系(E-PMS-CP/ PVDF和E-PDS-CP/PVDF)對3種不同有機污染物(CBZ、DCF和SMX)的去除表現(xiàn).以HA作為目標污染物,進一步研究了E-PS-CP/PVDF體系緩解膜污染的效果,并通過捕獲實驗確定了污染緩解機理.此外,通過對PMS與PDS的對比,確定了氧化劑對體系的影響,同時為復(fù)合體系中氧化劑的選擇提供依據(jù).

1 材料和方法

1.1 試驗材料

聚偏氟乙烯粉末(PVDF)購自美國蘇威有限公司;卡馬西平(CBZ)、雙氯芬酸鈉(DCF)和磺胺甲噁唑(SMX)購自西格瑪奧德里奇公司;過硫酸鈉購自上海阿拉丁有限公司;5%Nafion溶液購自美國杜邦有限公司;聚乙烯吡咯烷酮(PVP)購自麥克林生化科技有限公司;N,N-二甲基乙酰胺(DMAc)購自成都市科隆化學(xué)品有限公司;甲醇(MeOH)、叔丁醇(TBA)和糠醇(FFA)購自上海霍尼韋爾有限公司;多壁碳納米管(CNT)(直徑10～20nm,純度>95%,電導(dǎo)率>100S/cm)、過硫酸銨、吡咯(Py)購自重慶東川化工有限公司;腐殖酸(HA)購自美國Sigma-Aldrich公司.所有試劑均為分析級.

1.2 導(dǎo)電復(fù)合膜的制備

使用非溶劑誘導(dǎo)相分離方法制作聚偏氟乙烯超濾膜.首先將1g的聚乙烯吡咯烷酮,16g的聚偏氟乙烯(PVDF)和83g N,N-二甲基甲酰胺在60℃混合攪拌 12h形成鑄膜液.然后將鑄造液在60℃烘箱中靜置12h[17].使用刮膜棒將鑄膜液在干凈的玻璃板上快速刮成膜.然后,立即將玻璃板浸泡到自來水中.待膜完全凝固后,將膜轉(zhuǎn)移到去離子中,在室溫下浸泡48h,以去除膜體中殘留的溶劑[18].實驗中膜的直徑為 640mm,比表面積為 32.15cm2.

使用化學(xué)沉積法對聚偏氟乙烯超濾膜進行表面改性[19].首先,將0.2g碳納米管(CNT)、4mL吡咯(Py)和1mL 5%Nafion溶液溶解到無水乙醇溶液中,超聲處理2h,得到均勻溶液.用噴槍將溶液噴涂在聚偏氟乙烯超濾膜表面上.然后,將噴涂后的超濾膜浸入0.2mol/L的過硫酸銨 ((NH3)2S2O8)溶液中,使其與聚偏氟乙烯超濾膜表面上的碳納米管和吡咯交聯(lián)1h,最后取出膜并使用去離子水反復(fù)沖洗膜表面.將所制備的CP/PVDF膜儲存在4 ℃的去離子水中.為了進行比較,還分別制備了CNT/PVDF復(fù)合超濾膜和PPy/PVDF復(fù)合超濾膜.

1.3 試驗方法

試驗所用反應(yīng)裝置如圖1所示,當(dāng)使用不同體系去除60μmol/L的CBZ、DCF和SMX采用錯流過濾和濃水回流模式進行,由蠕動泵提供壓力驅(qū)動進料液,控制跨膜壓為0.1MPa.實驗過程中,在預(yù)設(shè)的時間間隔內(nèi)收集滲透液CBZ、DCF和SMX樣品,使用0.22um的濾膜過濾后,進行液相測試.所有的樣品在4℃下儲存,直到測量.

膜污染實驗仍采用錯流過濾和濃水回流模式進行,在每次實驗之前,使用超純水對不同膜進行預(yù)壓30min.在實驗過程中選取0.1g/L的HA作為模擬污染物.實驗中PMS及PDS投加量均為10mmol/L,電流密度為2.3mA/cm,初始pH值為7.0.實驗中通過電子天平記錄出水質(zhì)量,并通過公式進行通量計算.

此外,超濾膜的純水通量0通過式(1)計算[20]:

式中:是單位時間內(nèi)通過膜的滲透量,L;是相關(guān)的有效面積,m2;是過濾時間,h.

圖1 實驗裝置示意

Fig.1 The schematic diagram of experiment setup

1.進水池;2.蠕動泵;3.壓力表;4.超濾膜池; 5.出水池;6.電子天平;7.直流電源; 8.電腦

1.4 分析方法

SMOP(小分子溶解性有機污染物)濃度檢測:本研究涉及SMOP的分別有CBZ、DCF和SMX,采用高效液相色譜法(HPLC)檢測其濃度,,進樣體積均為10μL.色譜柱為 Cosmosil 5C18-msII柱(4.6mm× 150mm).詳細檢測條件如表1所示.

使用掃描電子顯微鏡(SEM,Shimadzu,Japan)來表征膜材料的表面.使用方形電阻計(SURAGUS EddyCus?TF map 2525,中國)測量不同復(fù)合膜的電阻.使用接觸角分析儀(SDC-100,中國盛鼎)測量不同復(fù)合膜的表面接觸角(CA).其中接觸角探針為超純水.測量之前,采用真空干燥箱,在60℃對超濾膜進行干燥72h,然后再進行測量.對每張超濾膜進行10次以上的檢測,并將其平均值作為其接觸角.采用碘化鉀滴定法測試PDS和PMS[21].采用傅里葉變換紅外光譜儀(FTIR,ERTEX 70,Bruker,德國)來表征膜表面和碳布表面的官能團.在測試之前,在60 ℃下對樣品進行真空干燥72h.波數(shù)范圍設(shè)置為 500～ 3000cm?1.

表1 HPLC 對 SMOP 的檢測方法

2 結(jié)果與討論

2.1 CP/PVDF復(fù)合超濾膜的表征

2.1.1 SEM分析 超濾膜的形貌與膜分離性質(zhì)以及抗污染性相關(guān).如圖2所示,原始PVDF膜的表面相對光滑平整,而經(jīng)過CNT和PPy(聚吡咯)改性后的PVDF膜表面相對粗糙,呈緊密的網(wǎng)狀結(jié)構(gòu),可觀察到復(fù)合膜表面覆蓋有彎曲的“蠕蟲狀”納米管結(jié)構(gòu),且未發(fā)現(xiàn)明顯的缺陷和團聚,這表明CNT/PPy成功地沉積在PVDF膜表面.

2.1.2 復(fù)合膜接觸角、方塊電阻和超純水通量分析 對制備的復(fù)合膜親水接觸角、方塊電阻以及純水通量進行表征,以了解復(fù)合膜的物理化學(xué)性質(zhì). 通過超純水接觸角的測試可以表明復(fù)合超濾膜的親疏水性,接觸角與超濾膜的親水性相關(guān),接觸角越小,膜材料親水性越強[22].方塊電阻越小表明超濾膜的導(dǎo)電性越好[23].如表2所示,原始PVDF膜的接觸角為85.3°,經(jīng)過負載疏水性的CNT后,負載碳納米管的超濾膜(C/PVDF)的接觸角為128°,這表明負載CNT后降低了超濾膜的表面親水性,而經(jīng)過負載PPy后,交聯(lián)聚吡咯的復(fù)合超濾膜(P/PVDF)的接觸角為46.5°,相比較于原始PVDF膜更加親水,最后,負載CNT/ PPy的CP/PVDF復(fù)合超濾膜的接觸角為75.5°,小于C/PVDF膜的接觸角,但大于P/PVDF膜的接觸角,這是因為疏水性的CNT和親水性的PPy成功地負載在CP/PVDF復(fù)合超濾膜上,低接觸角通常表明膜具有高表面能和強親水性,這為CP/PVDF復(fù)合超濾膜的水處理應(yīng)用奠定了基礎(chǔ).各種膜的方塊電阻結(jié)果如表2所示,原始PVDF膜本身不導(dǎo)電,負載CNT和PPy后,C/PVDF膜和P/PVDF膜的方塊電阻分別為95和528 Ω/sq,負載CNT/PPy的CP/PVDF復(fù)合超濾膜的方塊電阻為168 Ω/sq.CNT/PPy層為CP/PVDF復(fù)合超濾膜提供了良好的導(dǎo)電性,使其可以作為膜的陰極進行電過濾.單獨PVDF膜和三種復(fù)合膜的純水通量結(jié)果(表2)分析對比,原始PVDF膜的純水通量為0.95L/(m2×h×kPa),由于疏水性的CNT成功沉積在PVDF膜上,降低了PVDF膜的表面能,并且納米粒徑的CNT堵塞住了膜孔,因此C/PVDF膜的純水通量低于原始PVDF膜的純水通量.而負載的高親水性的PPy使得P/PVDF膜高于其他三種膜的純水通量.最后,CP/PVDF膜的純水通量與原始PVDF膜相近,主要是親水性的PPy增加了膜滲透性,同時,PPy的聚合也導(dǎo)致了納米顆粒CNT對膜孔堵塞的減緩.因此負載活性層后并未降低膜通量.并且,通過其他研究學(xué)者制備的Al2O3/PVDF[24]膜和TiO2/PVDF[25]膜相比,CP/PVDF膜具有更高的純水通量.

表2 不同膜的接觸角、方塊電阻和超純水通量

2.1.3 導(dǎo)電層穩(wěn)定性分析 濁度是來反映水中懸浮物含量的一個重要指標.使用純水對CP/PVDF膜進行36h的簡單超濾試驗.如圖3(a)所示,在低濃度范圍內(nèi),出水濁度與CNT的濃度線性相關(guān),隨著CNT濃度的提高,濁度也隨之提高.如圖3(b)所示,在36h的實驗過程中,出水濁度并未發(fā)生顯著變化,表明復(fù)合膜表面的導(dǎo)電層在運行期間未明顯掉落.因此,CP/PVDF膜具有較好的穩(wěn)定性.

2.2 不同體系對SMOP的去除

實驗考察了單獨CP/PVDF超濾體系、E-PDS- CP/PVDF、E-PMS-CP/PVDF反應(yīng)體系對卡馬西平(CBZ)、雙氯芬酸鈉(DCF)和磺胺甲噁唑(SMX)去除速率,由表3所示,單獨CP/PVDF超濾體系對3種小分子污染物幾乎沒有去除效果,因為超濾膜的截留分子量大使其難以有效攔截水中的SMOP[26].而通過外加電場和投加氧化劑后, E-PS-CP/PVDF反應(yīng)體系的速率常數(shù)遠高于單獨CP/PVDF超濾體系,以CBZ為例,E-PMS-CP/PVDF和E-PDS-CP/PVDF反應(yīng)體系對CBZ的一級動力學(xué)常數(shù)分別為22.3× 10-2min-1和16.7×10-2min-1,而單獨CP/PVDF超濾對CBZ的去除速率僅為0.051×10-2min-1,根據(jù)以上實驗結(jié)果可知,E-PS-CP/PVDF反應(yīng)體系可以實現(xiàn)對3種小分子有機污染物更有效的去除,這可能與更多的活性物質(zhì)(?OH,SO4?-)的生成有關(guān).

表3 不同體系對CBZ、DCF和SMX的去除速率

2.3 不同體系對膜污染的緩解

為了研究不同體系對膜污染的緩解能力,研究了通量衰減.如圖4(a)所示,當(dāng)HA原水溶液流經(jīng)超濾膜后,觀察到出水通量(0)在過濾前15min內(nèi)快速下降,最終出水比通量穩(wěn)定在0.586.當(dāng)向體系外加電場,將CP/PVDF膜作為陰極后(即E-CP/PVDF體系),膜污染得到了緩解,主要原因是增加電斥力的作用緩解了膜污染,帶負電荷的HA與膜陰極發(fā)生了強烈的排斥作用,因此,HA很難沉積在膜上[27-28].其次,負載的CNT/PPy層增加了PVDF膜的親水性,膜表面形成的水化層會減緩HA的沉積.并且,陰極表面會發(fā)生析氫反應(yīng)產(chǎn)生H2(式2),HA在膜表面的吸附和沉積會被產(chǎn)生的H2微小氣泡所減緩.

在此基礎(chǔ)上,向原水溶液中投加過PS(包括PMS和PDS)后,E-PS-CP/PVDF反應(yīng)體系明顯抑制了膜通量的下降,并且,E-PMS-CP/PVDF反應(yīng)體系比通量(0.93)略高于E-PDS-CP/PVDF反應(yīng)體系(0.842),說明E-PMS-CP/PVDF反應(yīng)體系可以更有效的緩解膜污染.如圖4(b),在反應(yīng)60min后,PMS和PDS在體系中的分解率分別為84%和70%,與E-PDS-CP/PVDF反應(yīng)體系相比,E-PMS-CP/PVDF體系可以更有效的活化PMS,從而體系的比通量下降的更慢.綜上,E-PS-CP/PVDF反應(yīng)體系能夠通過活化過硫酸鹽產(chǎn)生活性物質(zhì)提高緩解膜污染的能力[29-30].

傅里葉變化紅外光譜常用來測試碳材料表面的官能團.圖4(c)是CP/PVDF在不同體系中使用后的表面官能團變化.吸收波長為1650cm-1的羰基(C=O)出現(xiàn)在了受污染的膜表面[31-32],且單獨CP/PVDF超濾體系以及E-CP/PVDF體系中膜的污染物吸收峰強度遠遠高于E-PS-CP/PVDF體系膜的污染物吸收峰強度,說明污染物存在于受HA污染的膜表面,并且污染物更難沉積在E-PS-CP/PVDF體系中的膜表面,通過以上結(jié)果分析,可以證明E-PS-CP/PVDF反應(yīng)體系能夠減少HA在膜上的積累.

為了進一步研究超濾膜的表面形貌,分別對不同體系下HA過濾過程前后CP/PVDF膜進行SEM掃描,如圖5可以看到,原始CP/PVDF膜表面結(jié)構(gòu)致密,可以清晰地看到“蠕蟲狀”納米管結(jié)構(gòu)(圖5(a)),相比之下,當(dāng)使用單獨CP/PVDF超濾體系過濾HA溶液后,HA會對CP/PVDF膜產(chǎn)生嚴重的污染,膜表面變得相對光滑,形成了較厚的餅層(圖5(b)),這種濾餅會造成嚴重的不可逆膜污染[33].而當(dāng)向體系外加電場并投加PDS后,CP/PVDF膜表面的污染物數(shù)量較少,HA組分僅積累在小部分區(qū)域,CP/PVDF膜的表面結(jié)構(gòu)依舊清晰可見(圖5(c)),而向體系投加PMS并且在外加電場的作用下,過濾后的CP/PVDF膜的表面也僅有少部分的膜孔被HA組分覆蓋,膜的表面結(jié)構(gòu)在過濾過程中得到了有效的保護(圖5(d)).由此說明E-PS-CP/PVDF體系具有優(yōu)異的抗污染能力.

圖5 不同體系過濾過程前后CP/PVDF膜的掃描電鏡圖

2.4 自由基淬滅實驗

E-PS-CP/PVDF體系中PMS和PDS的活化可能是自由基反應(yīng)或非自由基反應(yīng),因此,選取甲醇(MeOH)為?OH(3.2 × 106mol?1s?1) 和SO4?-(= 9.7 × 108mol?1s?1)猝滅劑,?OH(= 3.8～7.6 × 108mol?1s?1)猝滅劑為叔丁醇(TBA),糠醇(FFA)可以作為1O2(= 1.2×108mol?1s?1)的淬滅劑進行猝滅實驗來論證[34].淬滅實驗結(jié)果如圖6所示,不加入淬滅劑時,E- PDS-CP/PVDF、E-PMS-CP/PVDF反應(yīng)體系膜通量在60min下降緩慢,最終穩(wěn)定分別為0.81和0.89,當(dāng)將100mmol過量的叔丁醇加入到體系中,體系對HA引起的膜污染的緩解受到了抑制,通量在15min內(nèi)快速下降,最終下降為0.80,這表明?OH參與體系對膜污染的緩解.將100mmol過量的甲醇加入到體系中時,體系對H A引起膜污染的緩解受到了進一步抑制,膜通量下降分別為0.75和0.74,說明除了?OH外,SO4? –也參與了體系對膜污染的緩解. 最后,將6mmol糠醇加入到體系后,體系的膜通量最低,下降為0.72,更加抑制了體系對膜污染的緩解,表明體系中存在1O2.根據(jù)目前的研究[35-40],推測E-PS-CP/ PVDF體系中產(chǎn)生自由基的反應(yīng)式見式(3)～式(7):

因此,E-PMS-CP/PVDF體系和E-PDS-CP/ PVDF 體系中緩解膜污染的緩解主要是體系中產(chǎn)生了?OH和SO4?-和1O2,且PMS作為氧化劑比PDS效果更好.

3 結(jié)論

3.1 該研究制備了單獨PVDF膜和CNT/PVDF、PPy/PVDF和CP/PVDF三種復(fù)合超濾膜,通過SEM分析,CNT/PPy層順利負載在CP/PVDF膜上, CP/PVDF膜的各項物理性質(zhì)均優(yōu)于單獨PVDF膜,接觸角為75°,方塊電阻為168 Ω/sq,純水通量為1.14L/(m2×h×kPa).

3.2 E-PS-CP/PVDF體系對3種SMOP(卡馬西平(CBZ)、雙氯芬酸鈉(DCF)和磺胺甲噁唑(SMX))的去除速率,其一級動力學(xué)常數(shù)均高于15×10-2min-1,遠高于單獨CP/PVDF超濾體系.以HA為目標污染物,對比了不同過濾體系的/0的變化情況, 在 60min內(nèi)E-PMS-CP/PVDF體系的膜通量下降至0.93,E- PDS-CP/PVDF膜通量下降至0.84,并且PS的持續(xù)分解說明E-PS-CP/PVDF體系可以有效活化PS,在傅里葉變化紅外光譜中,E-PS-CP/PVDF體系污染后的膜表面HA殘留明顯降低.證實了E-PS- CP/PVDF體系具有較好的抗污染能力.且PMS作為氧化劑比PDS具有更好的小分子去除和膜污染緩解表現(xiàn).

3.3 淬滅實驗證實了膜污染的緩解是由于體系中產(chǎn)生的?OH和SO4?-和1O2對HA的氧化作用導(dǎo)致.

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Degradation emerging contaminants and mitigation membrane fouling by electrochemical activation of persulfate.

LIU Yin, XU Qi-bin, SONG Zi-heng, LIU Suo, ZHAO Chun*

(Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400045, China)., 2023,43(11)：5757～5764

The occurrence of membrane fouling and the poor retention effect of small molecular organic pollutants have been important factors limiting the development of ultrafiltration technology. This study realized the mitigation of membrane fouling and the removal of small molecular organic pollutants (SMOP) in the ultrafiltration process by coupling advanced oxidation technology. Cross-linked polypyrrole carbon nanotubes were deposited on the surface of polyvinylidene fluoride (PVDF) membrane by spraying, and the crosslinked polypyrrole carbon nanotubes composite ultrafiltration membrane (CP/PVDF) with excellent conductivity was obtained. The performance of fouling mitigation (HA as the simulated pollutant) and removing small molecular organic pollutants was compared when peroxymonosulfate (PMS) and peroxodisulfate (PDS) were used as oxidants respectively. The results showed that the E-PS-CP/PVDF system had high removal ratios for three different small molecular organic pollutants , carbamazepine (CBZ), diclofenac sodium (DCF) and sulfamethoxazole (SMX), and its first-order kinetic constants were higher than 15×10-2min-1, much higher than that of the ultrafiltration system alone (the highest was 0.072×10-2min-1). E-PS-CP/PVDF system had obvious membrane pollution mitigation effect.When using PMS and PDS as electrolytes, the normalized membrane flux only decreased to 0.93and 0.84 within 60min, respectively. The applied electric field and the oxidation of oxidizing hydroxyl radicals on HA changed the interaction of pollutants on the membrane surface and reduced the deposition of HA on the membranes. In addition, the fouling mitigation mechanism of E-PS-CP/PVDF system to alleviate membrane fouling was explored through quenching experiments. The results of mechanism experiments showed that the main reason for alleviating membrane fouling in E-PS-CP/PVDF system was the?OH, SO4?-and1O2generated by the cathodic activation of PS, and PMS had better performance as oxidant than PDS. Therefore, E-PS-CP/PVDF system can alleviate membrane pollution and remove small molecular organic pollutants during ultrafiltration, and has a good application prospect in the field of actual water treatment.

PVDF；CP/PVDF membranes；persulfate；electrically activation；humic acid

X703.1

A

1000-6923(2023)11-5757-08

劉 寅(1998-),男,山東臨沂人,重慶大學(xué)碩士研究生,主要從事基于過硫酸鹽的高級氧化研究.發(fā)表論文1篇.1742552368@qq.com.

劉 寅,許岐斌,宋子恒,等.CP/PVDF膜電活化PS降解新污染物及緩解膜污染 [J]. 中國環(huán)境科學(xué), 2023,43(11):5757-5764.

Liu Y, Xu Q B, Song Z H, et al. Degradation emerging contaminants and mitigation membrane fouling by electrochemical activation of persulfate [J]. China Environmental Science, 2023,43(11):5757-5764.

2023-04-06

國家自然科學(xué)基金資助項目(22076015);重慶市自然科學(xué)基金(cstc2019jcyj-msxmX0463);重慶市醫(yī)學(xué)科研項目(2021MSXM083)

* 責(zé)任作者, 教授, pureson@163.com