草酸強化天然鐵礦石異相光助Fenton催化降解萘酚

胡彩萍,鎖進然,丁冠濤,徐天緣,魏善明,王 坤*

草酸強化天然鐵礦石異相光助Fenton催化降解萘酚

胡彩萍1,鎖進然2,丁冠濤1,徐天緣2,魏善明1,王 坤2*

(1.山東省地質(zhì)礦產(chǎn)勘查開發(fā)局八〇一水文地質(zhì)工程地質(zhì)大隊(山東省地礦工程勘察院),山東省地下水環(huán)境保護與修復(fù)工程技術(shù)研究中心,山東 濟南 250014；2.中國礦業(yè)大學(xué)資源與地球科學(xué)學(xué)院,江蘇 徐州 221116)

對安徽馬鞍山天然鐵礦石的結(jié)構(gòu)與成分進行表征分析, 利用響應(yīng)曲面方法箱線型設(shè)計(BBD)評估影響萘酚降解效率因素之間的交互作用, 并探討草酸強化鐵礦石異相光助Fenton催化體系的機理.結(jié)果顯示,馬鞍山鐵礦石的礦石礦物主要為磁鐵礦.性能評價結(jié)果顯示草酸顯著提高鐵礦石異相光助Fenton催化性能,萘酚去除率由40%提高至>99%.BBD設(shè)計表明影響萘酚降解的主導(dǎo)因素是草酸濃度,其次是H2O2濃度,鐵礦石劑量的影響稍小,三者之間均存在交互影響.EPR結(jié)果表明草酸的引入可以顯著提高體系中的CO2??和O2??含量.草酸強化鐵礦石異相光助Fenton高效催化降解萘酚主要歸因于草酸與鐵礦石形成的草酸鐵絡(luò)合物的光分解提高體系中O2??產(chǎn)量,另一方面光分解產(chǎn)物Fe(Ⅱ)加速Fenton反應(yīng)產(chǎn)生?OH的速率.研究結(jié)果可為綠色環(huán)保水污染物控制技術(shù)研發(fā)提供指導(dǎo).

鐵礦；草酸；異相Fenton；多環(huán)芳烴；機理

隨著全球污染物對公眾健康和環(huán)境的潛在不利影響的認(rèn)識不斷提高,水體有毒有害物質(zhì)環(huán)境污染修復(fù)越來越受到關(guān)注.多環(huán)芳烴(PAHs)由于其有毒、遺傳毒性、致突變和/或致癌特性而受到重大關(guān)注,被認(rèn)為是優(yōu)先控制有機污染物[1-5].由于人類活動,PAHs廣泛分布于空氣、水、土壤、植物以及動物和它們的代謝產(chǎn)物中,已經(jīng)對人類健康和可持續(xù)發(fā)展產(chǎn)生了嚴(yán)重威脅[5].因此,亟需發(fā)展針對這類難降解有機污染物的高效治理技術(shù).礦物的特殊結(jié)構(gòu)與性能(如離子交換性、孔隙結(jié)構(gòu)、催化活性等)使其具有凈化水體污染物的功能[6-7],利用天然礦物消除水體污染被認(rèn)為是道法自然的一種環(huán)境友好型水處理技術(shù),具有良好應(yīng)用前景.鐵氧化物(包括鐵的氫氧化物和氧化物)是地表系統(tǒng)的重要組成礦物,具有資源豐富、環(huán)境友好和電子輸運能力強等優(yōu)點,可以通過吸附或者鐵循環(huán)(Fe(III)/Fe(II))實現(xiàn)元素地球化學(xué)循環(huán)凈化環(huán)境污染物[8-10].磁鐵礦是地球表層中最常見的含亞鐵礦物,其結(jié)構(gòu)中的Fe2+是重要的電子供體.此外,磁鐵礦結(jié)構(gòu)中的八面體同時被Fe2+和Fe3+占據(jù),電子在這兩種氧化態(tài)之間可以迅速轉(zhuǎn)移,以此發(fā)生氧化還原反應(yīng)[10].磁鐵礦已被證實是優(yōu)良的Fenton試劑,能有效活化H2O2產(chǎn)生×OH氧化降解有機污染物[11-12].我國磁鐵礦資源豐富,環(huán)境相容性好,如四川攀枝花釩鈦磁鐵礦、安徽馬鞍山鐵礦床等[13-15].因此,利用天然磁鐵礦構(gòu)建異相Fenton體系用于PAHs污染控制具有良好的發(fā)展前景.

本研究以安徽馬鞍山鐵礦石為催化劑,萘酚為目標(biāo)污染物,探討草酸強化天然鐵礦石異相Fenton降解萘酚的催化性能與相關(guān)機理,并利用響應(yīng)曲面方法評估草酸含量、鐵礦石劑量、H2O2含量影響因素之間的交互作用.此外,通過研究活性自由基的產(chǎn)生揭示草酸強化鐵礦石異相Fenton降解萘酚的機理.本研究可為利用天然礦物發(fā)展綠色高效的多環(huán)芳烴污染控制技術(shù)提供指導(dǎo).

1 材料與方法

1.1 試劑

草酸、萘酚、氫氧化鈉、叔丁醇、對苯醌均為分析純,雙氧水(質(zhì)量分?jǐn)?shù)30%),鹽酸(質(zhì)量分?jǐn)?shù)37%)購于國藥集團化學(xué)試劑有限公司.實驗用水均為超純水.

1.2 實驗設(shè)計與方法

天然鐵礦石來源于安徽省馬鞍山市南山礦區(qū)高村鐵礦床,經(jīng)研磨過200目篩后備用.天然鐵礦石的物相組成由X射線衍射儀(XRD,Bruker D8Advance X,德國)表征分析.元素組成與價態(tài)分析由X射線光電子能譜(XPS,Thermo Fisher K-Alpha,美國)表征,污染碳C 1s標(biāo)準(zhǔn)結(jié)合能284.8 eV用來校正各元素的鍵能位移.主量元素組成采用X射線熒光光譜儀(XRF,PANalytical PW2424,荷蘭)進行硅酸鹽巖主微量精密分析,其中FeO含量采用Fe-VOL05滴定法測定氧化亞鐵,具體為鐵礦石用氫氟酸與硫酸分解,溶液中剩余的氟加入硼酸絡(luò)合去除,以二苯胺磺酸鈉為指示劑,用基準(zhǔn)重鉻酸鉀溶液滴定亞鐵的含量,并計算FeO的量.

草酸強化天然鐵礦石異相Fenton降解萘酚實驗過程如下:稱取1g/L的天然鐵礦石置于裝有100mL萘酚溶液(10mg/L,pH值約6.5)的250mL燒杯中,并加入1mmol/L的草酸和6.5mmol/L的H2O2.將燒杯置于磁力攪拌器上并開啟裝有濾波片(> 420nm)的氙燈(模擬可見光)進行光反應(yīng).反應(yīng)一定時間后取約1mL的樣品過0.22μm的濾膜,而后檢測上清液中萘酚濃度.利用高效液相色譜(HPLC,賽默飛Vanquish Core,美國)測定萘酚的濃度,進樣體積為20μL,以甲醇、水和醋酸的混合物為流動相,二者體積比為75:25,流速為1.0mL/min.紫外檢測器和柱溫設(shè)置在230nm和40°C.

草酸強化天然鐵礦石異相Fenton降解萘酚影響因素之間的交互作用采用箱線圖設(shè)計(BBD)進行研究,反應(yīng)時間為30min,設(shè)計因素見表1.

表1 BBD設(shè)計因素與代碼

2 結(jié)果與討論

2.1 天然鐵礦石物相與成分分析

馬鞍山天然鐵礦石的XRD圖見圖1.圖中可以觀察到從磁鐵礦(JCPDS No.65-3107)和韭閃石(JCPDS No.23-1406)的衍射峰,表明其主要由這兩種礦物構(gòu)成.光助Fenton反應(yīng)后鐵礦石的結(jié)構(gòu)未發(fā)生明顯變化,表明其具有良好的穩(wěn)定性.

圖1 天然鐵礦石的XRD圖譜

為了進一步探究馬鞍山天然鐵礦石的構(gòu)成,采用XPS對天然鐵礦石進行進一步表征.XPS總元素圖譜如圖2(a)所示,可以看出天然鐵礦石的主要元素為Fe、O、Si、Ca和Mg等.由Fe 2p XPS圖譜可知(圖2(b)),天然鐵礦石中的Fe有3種形態(tài)位于713.26、710.86和709.22eV,分別代表四面體中的Fe3+、八面體中的Fe3+和八面體中的Fe2+[26],間接證明了磁鐵礦物相的存在.反應(yīng)后Fe 2p XPS譜圖中出現(xiàn)了位于711.18eV的新峰,這主要歸因于天然鐵礦吸附的草酸在天然鐵礦石表面形成了草酸鐵絡(luò)合物[27],該絡(luò)合物在光的激發(fā)下發(fā)生分解產(chǎn)生活性氧物種.此外,本文還檢測到了Ti的存在,如圖2(c)所示.可以看出Ti XPS圖中有兩個明顯的峰分別位于464.31和458.74 eV,分別歸屬于磁鐵礦中類質(zhì)同象摻雜的Ti 2p1/2和Ti 2p3/2峰[28].

此外,為了獲知馬鞍山天然鐵礦石中各元素的含量比例,采用XRF對樣品進行了定量分析,并采用滴定法獲取了亞鐵氧化物的含量,結(jié)果如表2所示.從表中可以看出,鐵礦石中Fe2O3和FeO含量分別為37.21%和15.10%.結(jié)合XRD分析結(jié)果,Fe2O3和FeO主要來源于磁鐵礦.SiO2、Al2O3、CaO、MgO、Na2O來源于韭閃石等脈石硅酸鹽礦物相.少量TiO2指示馬鞍山天然磁鐵礦為含鈦磁鐵礦,與XPS結(jié)果一致.

表2 安徽馬鞍山鐵礦石主量元素成分表

2.2 草酸強化天然鐵礦石異相Fenton催化降解萘酚的性能評價

暗反應(yīng)條件下不同實驗體系中萘酚的去除效率如圖3(a)所示,可以看出單獨的鐵礦石體系中萘酚幾乎未被去除,表明鐵礦石在暗反應(yīng)條件下對萘酚沒有吸附能力.而單獨的H2O2體系、單獨草酸體系或者二者的共同作用下,萘酚也難以被氧化還原降解,表明萘酚為相對穩(wěn)定的污染物.此外,天然鐵礦石與H2O2構(gòu)成的異相Fenton體系中萘酚的去除率依舊很低,這主要是由于中性條件下Fenton反應(yīng)的速率非常低,天然鐵礦石難以誘導(dǎo)H2O2產(chǎn)生活性氧物種降解萘酚.另外,天然鐵礦石與草酸共同存在時也難以催化降解萘酚,這主要是由于暗反應(yīng)條件下沒有激發(fā)源激發(fā)草酸鐵絡(luò)合物分解產(chǎn)生活性氧物種.而當(dāng)鐵礦石、H2O2和草酸均添加時,反應(yīng)60min后體系中萘酚去除率可達(dá)到32.1%,高于未添加草酸的體系.這是因為形成的草酸鐵絡(luò)合物在同等實驗條件下分解H2O2產(chǎn)生的×OH能力要遠(yuǎn)高于傳統(tǒng)Fenton反應(yīng)[29].

而在可見光的激發(fā)下,單獨的草酸難以降解萘酚.而H2O2體系中,萘酚的去除率約為18%,表明可見光可以激發(fā)H2O2分解為活性氧物種.而進一步添加草酸的共存體系中,萘酚的去除率并未顯著增加,表明H2O2和草酸之間不存在協(xié)同催化作用.在可見光協(xié)同鐵礦石體系中,萘酚的去除率約為19.4%,這主要歸功于磁鐵礦的半導(dǎo)體效應(yīng)[30].而在異相光助Fenton體系中,萘酚去除率達(dá)到了39.5%,表明可見光可以提升異相Fenton體系的催化性能/活性.在鐵礦石與草酸構(gòu)建的類光助Fenton體系中,萘酚發(fā)生了快速分解,在20min內(nèi)去除率可達(dá)到63.7%,反應(yīng)60min后去除率高達(dá)94.5%.這主要是因為草酸吸附在磁鐵礦表面形成了草酸鐵絡(luò)合物,在可見光的激發(fā)下,該絡(luò)合物發(fā)生快速光分解產(chǎn)生活性氧物種[19].而在光+鐵礦石+ H2O2+草酸的體系中,萘酚的降解速率最快.相比于異相光助Fenton體系,萘酚的去除率由39.5%提高至趨于100%,表明草酸的存在能顯著增強鐵礦石異相光助Fenton反應(yīng)的活性.

實驗條件:鐵礦石劑量1.0g/L,草酸濃度1mmol/L, H2O2濃度6.5mmol/L,萘酚溶液初始濃度10mg/L,萘酚溶液初始pH 6.5

2.3 響應(yīng)曲面分析影響因素相關(guān)性

2.3.1 方差分析 為了探究鐵礦石劑量、草酸濃度和H2O2濃度對草酸強化異相光助Fenton降解萘酚的影響,采用響應(yīng)曲面法中的箱線型設(shè)計(BBD)對三種主導(dǎo)因素進行優(yōu)化篩選,并分析之間的交互影響.實驗設(shè)計見如表1,實驗結(jié)果如表3所示.

采用“Expert-Design”軟件對萘酚去除率數(shù)據(jù)進行回歸分析,得到表3中的模型分析.通過對鐵礦石劑量、草酸濃度和雙氧水濃度進行箱線型設(shè)計,得到相應(yīng)的二次方程模型:

=63.32+7.53+11.22+26.98-1.56-

0.934-4.27-11.972-6.62-7.482(1)

式中:為響應(yīng)值萘酚去除率;、、C分別為鐵礦石劑量、草酸濃度和雙氧水濃度的編碼值.

由表3可見,通過對實驗結(jié)果進行擬和的二次模型方差分析中值為194.23,值<0.0001,失擬項不顯著,決定系數(shù)為2=0.9960,說明模型可以解釋實驗所得萘酚去除率的變化,也表明獨立變量之間的相關(guān)性較好,表示方程擬合較好.對二次模型中回歸系數(shù)進行顯著性檢驗,結(jié)果表明<0.0500為影響顯著,而所有因素中均表現(xiàn)出效果顯著,且草酸濃度和H2O2濃度交互影響顯著.從表3中值可以看出,、、、、2、2、2對萘酚降解率均有明顯的影響,且均值越大影響越顯著,由此可以判斷對萘酚降解率影響的順序為>>2>>2>2>,草酸濃度的影響最大,其次為H2O2濃度.

表3 二次回歸模型的方差分析(以萘酚去除率為響應(yīng)對象)

2.3.2 響應(yīng)曲面分析 從圖4可知,固定草酸濃度為0.55mmol/L時,當(dāng)鐵礦石劑量為0.2g/L萘酚去除率隨H2O2濃度的增加呈輕微的上升趨勢.此外,當(dāng)H2O2濃度較低時,萘酚的去除率并未隨鐵礦石劑量的增加而顯著上升,表明鐵礦石對萘酚的吸附效果一般且0.2g/L的鐵礦石足以激活0.5mmol/L的H2O2,與單因素實驗結(jié)果一致.而當(dāng)H2O2濃度與鐵礦石劑量同步增加時,萘酚去除率呈顯著上升趨勢,表明H2O2與鐵礦石表現(xiàn)出一定的交互影響.

從圖5可知,固定H2O2濃度為3.5mmol/L時,萘酚去除率隨草酸濃度的增加顯著升高.當(dāng)鐵礦石劑量為0.2g/L時,草酸濃度從0.1mmol/L增加到1mmol/L萘酚的去除率增加了將近6倍.而當(dāng)鐵礦石劑量也隨之增加時,可進一步提高萘酚的降解率,表明草酸濃度與鐵礦石劑量存在一定的交互作用.

圖5 鐵礦石劑量和草酸濃度對萘酚降解率影響的三維曲面圖和等高線圖

圖6 H2O2濃度和草酸濃度對萘酚降解率影響的三維曲面圖和等高線圖

從圖6可知,當(dāng)固定磁鐵礦石劑量為0.6g/L時,萘酚的去除率隨草酸濃度和H2O2濃度的增加而增加,而草酸濃度對萘酚降解的影響要高于H2O2濃度.例如,當(dāng)H2O2濃度固定為0.5mmol/L時,萘酚的去除率隨著草酸濃度增加(0.1～1mmol/L)可以從7.4%增加到將近71.7%;而當(dāng)草酸濃度固定為0.1mmol/L, H2O2濃度由0.5mmol/L增加到6.5mmol/L萘酚的降解率由7.4%提升至35.3%,這一分析結(jié)果與表3回歸模型擬合結(jié)果一致.

2.4 機理分析

為了探討萘酚降解的主導(dǎo)活性物種,采用添加抑制劑的方式篩選主導(dǎo)活性物種,實驗結(jié)果如圖7所示.從圖中可知,當(dāng)添加?OH抑制劑異丙醇時,萘酚的去除率由99%降低至不到20%;而當(dāng)O2??抑制劑NBT添加后,萘酚去除率由99%降低至38%左右.以上結(jié)果表明草酸強化鐵礦石異相光助Fenton催化降解萘酚體系中?OH和O2??均參與了萘酚降解,且?OH對萘酚降解的貢獻率略高于O2??.除了自由基途徑,鐵氧化物在活化氧化劑時可能會產(chǎn)生高價鐵與高價鐵氧物種,這些活性物種被認(rèn)為可以通過非自由基途徑降解有機污染物[25].DMSO可以與高價鐵物種通過2步電子轉(zhuǎn)移途徑反應(yīng)生成DMSO2,因此,DMSO常被用于檢測高價鐵物種的探針[25].為此,本文使用100mM的DMSO作為高價鐵物種的抑制劑,探究可見光/鐵礦石/ H2O2/草酸體系中的非自由基途徑.實驗結(jié)果顯示萘酚的去除率為78%,下降了約21%,表明該體系中存在非自由基途徑.以上結(jié)果表明草酸強化天然鐵礦石異相光助Fenton體系主要以自由基途徑為主,通過?OH和O2??的攻擊來降解有機污染物.

圖7 自由基抑制劑對萘酚降解的影響

實驗條件:異丙醇濃度100mmol/L, NBT濃度5mmol/L, DMSO濃度100mmol/L

圖9 草酸強化鐵礦石異相光助Fenton降解萘酚機理示意

2.5 重復(fù)實驗測試

為了驗證鐵礦石的使用壽命,評估了其重復(fù)使用降解萘酚的性能,結(jié)果如圖10(a)所示,鐵礦石重復(fù)使用5次時,其異相Fenton催化降解萘酚的能力并未明顯下降,萘酚的去除率能高達(dá)99%,表明該體系具有優(yōu)越的穩(wěn)定性,有良好的潛能發(fā)展成有機污染的控制技術(shù).

圖10 鐵礦石重復(fù)使用降解萘酚性能測試

實驗條件:鐵礦石劑量1.0g/L,草酸濃度1mmol/L, H2O2濃度6.5 mmol/L, 萘酚溶液初始濃度10mg/L,萘酚溶液初始pH 6.5

圖11 草酸強化天然鐵礦石異相光助Fenton體系總鐵離子濃度隨時間變化

實驗條件:鐵礦石劑量1.0g/L,草酸濃度1mmol/L, H2O2濃度6.5mmol/L, 萘酚溶液初始濃度10mg/L,萘酚溶液初始pH 6.5

從反應(yīng)后XRD圖(圖1)可知,天然鐵礦石經(jīng)過光助Fenton反應(yīng)后結(jié)構(gòu)未發(fā)生明顯的變化,表明其具有良好的穩(wěn)定性.此外,光反應(yīng)后溶液中鐵離子浸出量為2.24mg/L(圖11),約占投入量的0.59%,進一步說明了天然磁鐵礦具有良好的穩(wěn)定性.總之,天然鐵礦石良好的穩(wěn)定性是其循環(huán)使用多次后仍可高效降解有機污染物的原因.

3 結(jié)論

安徽馬鞍山鐵礦石的礦石礦物主要為磁鐵礦.性能評價實驗顯示鐵礦石構(gòu)建的異相光助Fenton體系在中性條件下降解萘酚的去除僅為40%,而當(dāng)添加草酸后萘酚去除速率顯著加快,反應(yīng)60min時,萘酚幾乎被完全去除.BBD設(shè)計結(jié)果顯示對萘酚降解率影響最大的是草酸濃度,其次為H2O2濃度,鐵礦石劑量影響較小.草酸強化鐵礦石異相光助Fenton降解萘酚體系中,影響萘酚降解的自由基為×OH和O2??,其中主導(dǎo)為×OH.草酸引入鐵礦石異相光助Fenton體系后,產(chǎn)生了CO2??,進一步促進了O2??的產(chǎn)生量.此外,草酸的引入也能促進Fe(Ⅱ)的產(chǎn)生,從而加快了鐵礦石異相光助Fenton體系,提高了體系中×OH的含量.

[1] Kim K H, Jahan S A, Kabir E, et al. A review of airborne polycyclic aromatic hydrocarbons (PAHs) and their human health effects [J]. Environment International, 2013,60:71-80.

[2] HaritashA, Kaushik C. Biodegradation aspects of polycyclic aromatic hydrocarbons (PAHs): a review [J]. Journal of Hazardous Materials, 2009,169:1-15.

[3] Han J, Liang Y, Zhao B, et al. Polycyclic aromatic hydrocarbon (PAHs) geographical distribution in China and their source, risk assessment analysis [J]. Environmental Pollution, 2019,251:312-327.

[4] 劉明洋,李會茹,宋愛民,等.環(huán)境和人體中氯代/溴代多環(huán)芳烴的研究進展—污染來源、分析方法和污染特征 [J]. 中國環(huán)境科學(xué), 2021, 41(4):1842-1855.Liu M Y, Li H r, Song A m et al. A review of chlorinated/ brominated polycyclic aromatic hydrocarbons in the environment and human: Sources, analysis methods and pollution characteristics. [J]. China Environmental Science, 2021,41(4):1842-1855.

[5] Ghosal D, Ghosh S, Dutta T K, et al. Current state of knowledge in microbial degradation of polycyclic aromatic hydrocarbons (PAHs): A review [J]. Frontiers in Microbiology, 2016, 7:1369.

[6] Suryanto B H, Wang Y, Hocking R K, et al. Overall electrochemical splitting of water at the heterogeneous interface of nickel and iron oxide [J]. Nature Communications, 2019,10:5599.

[7] Mana S C A, Hanafiah M M, Chowdhury A J K. Environmental characteristics of clay and clay-based minerals [J]. Geology, Ecology, and Landscapes, 2017,(1):155-161.

[8] Wei K, Liu X, Cao S, et al. Fe2O3@FeB composites facilitate heterogeneous Fenton process by efficient Fe (III)/Fe (II) cycle and in-situ H2O2generation [J]. Chemical Engineering Journal Advances, 2021,8:100165.

[9] Zhong Y, Liang X, He Z, et al. The constraints of transition metal substitutions (Ti, Cr, Mn, Co and Ni) in magnetite on its catalytic activity in heterogeneous Fenton and UV/Fenton reaction: From the perspective of hydroxyl radical generation [J]. Applied Catalysis B: Environmental, 2014,150:612-618.

[10] He H, Zhong Y, Liang X, et al. Natural magnetite: An efficient catalyst for the degradation of organic contaminant [J]. Scientific Reports, 2015,5:1-10.

[11] Munoz M, De Pedro Z M, Casas J A, et al. Preparation of magnetite-based catalysts and their application in heterogeneous Fenton oxidation–a review [J]. Applied Catalysis B: Environmental, 2015,176:249-265.

[12] Sun H, Xie G, He D, et al. Ascorbic acid promoted magnetite Fenton degradation of alachlor: Mechanistic insights and kinetic modeling [J]. Applied Catalysis B: Environmental, 2020,267:118383.

[13] Wang K, Wang C Y, Ren Z Y. Apatite-hosted melt inclusions from the Panzhihua gabbroic-layered intrusion associated with a giant Fe–Ti oxide deposit in SW China: insights for magma unmixing within a crystal mush [J]. Contributions to Mineralogy and Petrology, 2018, 173:1-14.

[14] Wang k, Dong H, Ou Q, et al. Large-scale liquid immiscibility in the Hongge layered intrusion hosting a giant Fe-Ti oxide deposit in SW China [J]. Ore Geology Reviews, 2021,136:104268.

[15] 黃 濤.安徽省馬鞍山市象塘鐵礦地質(zhì)特征及成因 [J]. 金屬礦山, 2019,9:141-146.Huang Tao. Geological characteristics and genesis of Xiangtang Iron Deposit in Maanshan City, Anhui Province [J]. Metal Mine, 2019,9: 141-146.

[16] Zhang M H, Dong H, Zhao L, et al. A review on Fenton process for organic wastewater treatment based on optimization perspective [J]. Science of the Total Environment, 2019,670:110-121.

[17] 謝欣卓,鐘金魁,李 靜,等.Fe3O4-nZVI類Fenton法降解水中磺胺甲惡唑謝 [J]. 中國環(huán)境科學(xué), 2022,42(7):3103-3111. Xie X Z, Zhong J K, Li J, et al. Degradation of sulfamethoxazole in water by Fenton-like method using Fe3O4-nZVI [J]. China Environmental Science, 2022,42(7):3103-3111.

[18] Xu T, Zhu R, Zhu G, et al. Mechanisms for the enhanced photo- Fenton activity of ferrihydrite modified with BiVO4at neutral pH [J]. Applied Catalysis B: Environmental, 2017,212:50-58.

[19] Xu T, Zhu R, Shang H, et al. Photochemical behavior of ferrihydrite-oxalate system: Interfacial reaction mechanism and charge transfer process [J]. Water Research, 2019,159:10-19.

[20] Li F, Koopal L, Tan W. Roles of different types of oxalate surface complexes in dissolution process of ferrihydrite aggregates [J]. Scientific Reports, 2018,8:1-13.

[21] Tyutereva Y E, Sherin P S, Polyakova E V, et al. Photodegradation of para-arsanilic acid mediated by photolysis of iron (III) oxalate complexes [J]. Chemosphere, 2020,261:127770.

[22] Pang H, Zhang Q, Wang H, et al. Photochemical aging of guaiacol by Fe (III)–oxalate complexes in atmospheric aqueous phase [J]. Environmental Science & Technology, 2018,53:127-136.

[23] Salazar C, Nanny M A. Influence of hydrogen bonding upon the TiO2photooxidation of isopropanol and acetone in aqueous solution [J]. Journal of Catalysis, 2010,269:404-410.

[24] Yang Y Y, Zhang X G, Niu C G, et al. Dual-channel charges transfer strategy with synergistic effect of Z-scheme heterojunction and LSPR effect for enhanced quasi-full-spectrum photocatalytic bacterial inactivation: new insight into interfacial charge transfer and molecular oxygen activation [J]. Applied Catalysis B: Environmental, 2020,264: 118465.

[25] Jian H, Fang Y, Yue G, et al. Efficient removal of pyrene by biochar supported iron oxide in heterogeneous Fenton-like reaction via radicals and high-valent iron-oxo species [J]. Separation and Purification Technology, 2021,265:118518.

[26] Radu T, Petran A, Olteanu D, et al. Evaluation of physico- chemical properties and biocompatibility of new surface functionalized Fe3O4clusters of nanoparticles [J]. Applied Surface Science, 2020,501: 144267.

[27] Xu T, Fang Y, Tong T, et al. Environmental photochemistry in hematite-oxalate system: Fe(III)-Oxalate complex photolysis and ROS generation [J]. Applied Catalysis B: Environmental, 2021,283: 119645.

[28] Kuznetsov M, Zhuravlev J F, Gubanov V. XPS analysis of adsorption of oxygen molecules on the surface of Ti and TiNx films in vacuum [J]. Journal of Electron Spectroscopy and Related Phenomena, 1992,58: 169-176.

[29] Pang F, Zhang R, Lan D, et al. Synthesis of magnetite– semiconductor–metal trimer nanoparticles through functional modular assembly: a magnetically separable photocatalyst with photothermic enhancement for water reduction [J]. ACS Applied Materials & Interfaces, 2018,10:4929-4936.

[30] Xue X, Hanna K, Despas C, et al. Effect of chelating agent on the oxidation rate of PCP in the magnetite/H2O2system at neutral pH [J]. Journal of Molecular Catalysis A: Chemical, 2009,311:29-35.

[31] Park J S, Wood P M, Davies M J, et al. A kinetic and ESR investigation of iron (II) oxalate oxidation by hydrogen peroxide and dioxygen as a source of hydroxyl radicals [J]. Free Radical Research, 1997,27:447-458.

[32] Wang Z, Xiao D, Liu J. Diverse redox chemistry of photo/ferrioxalate system [J]. RSC Advances, 2014,4:44654.

[33] Xu T, Zhu R, Shang H, et al. Photochemical behavior of ferrihydrite- oxalate system: Interfacial reaction mechanism and charge transfer process [J]. Water Research, 2019,159:10-19.

Oxalate enhanced heterogeneous photo-Fenton activity of natural iron mineral for naphthol degradation.

HU Cai-ping1, SUO Jin-ran2, DING Guan-tao1, XU Tian-yuan2, WEI Shan-ming1, WANG Kun2*

(1.Shandong Engineering Research Center for Environmental Protection and Remediation on Groundwater, 801 Institute of Hydrogeology and Engineering Geology, Shandong Provincial Bureau of Geology & Mineral Resources, Jinan 250014, China；2.School of Resource and Geosciences, China University of Mining and Technology, Xuzhou 221116, China)., 2023,43(11)：6016～6024

In this study, the structure and composition of the natural iron mineral collected from Maanshan were characterized, and the box-plot design (BBD) of the response surface method was used to evaluate the influencing factors. Moreover, the mechanism of enhanced heterogeneous photo-Fenton activity by oxalate was discussed. The characterization result show that the Maanshan iron mineral is mainly magnetite. The performance evaluation results reveal that oxalate can significantly improve the heterogeneous photo-Fenton activity of the iron mineral, and the removal rate of naphthol increased from 40% to >99% after oxalate addition. The BBD design shows that the dominant factor affecting the degradation of naphthol was oxalate concentration, followed by H2O2concentration. The EPR results reveal that introducing oxalate could significantly improve the generation of CO2??and O2??. The efficient catalytic degradation of naphthol was mainly attributed to the photolysis of iron oxalate complexes formed on iron mineral, which can accelerate the production of O2??. Additionally, the produced Fe(Ⅱ) can accelerate the generation of ?OH via Fenton reaction. The findings can provide guidance for the development of green environmental water pollutant control technology using natural minerals.

iron mineral；oxalate；heterogeneous Fenton；polycyclic aromatic hydrocarbon (PAHs)；mechanism

X52

A

1000-6923(2023)11-6016-09

胡彩萍(1976-),女,山東西人,研究員,碩士,主要從事地質(zhì)勘查、生態(tài)修復(fù)、地?zé)峥辈榉较蜓芯?發(fā)表論文20余篇. caipinghu126@126. com.

胡彩萍,鎖進然,丁冠濤,等.草酸強化天然鐵礦石異相光助Fenton催化降解萘酚 [J]. 中國環(huán)境科學(xué), 2023,43(11):6016-6024.

Hu C P, Suo J R, Ding G R, et al. Oxalate enhanced heterogeneous photo-Fenton activity of natural iron mineral for naphthol degradation [J]. China Environmental Science, 2023,43(11):6016-6024.

2023-03-23

山東省地下水環(huán)境保護與修復(fù)工程技術(shù)研究中心開放基金資助項目(801KF2021-13);國家自然科學(xué)基金資助項目(22176212);江蘇省“雙創(chuàng)博士”基金資助項目(JSSCBS20211225)

* 責(zé)任作者, 副教授, kwang@cumt.edu.cn