非均相活化劑磁性納米CoFe2O4的制備及其活性評(píng)價(jià)

劉佳露,張鳳君,彭新晶

非均相活化劑磁性納米CoFe2O4的制備及其活性評(píng)價(jià)

劉佳露1*,張鳳君2,彭新晶3

(1.中核武漢核電運(yùn)行技術(shù)股份有限公司,湖北 武漢 430223；2.吉林大學(xué)地下水資源與環(huán)境教育部重點(diǎn)實(shí)驗(yàn)室,吉林 長(zhǎng)春 130021；3.沈陽(yáng)化工大學(xué)環(huán)境與安全工程學(xué)院,遼寧 沈陽(yáng) 110142)

采用溶膠-凝膠法制備了磁性納米鐵酸鈷(CoFe2O4)固體顆粒,并采用掃描電鏡(SEM),X射線衍射儀(XRD),傅里葉變換紅外光譜儀(FT-IR)和振動(dòng)樣品磁強(qiáng)計(jì)對(duì)樣品進(jìn)行表征分析.以磁性納米CoFe2O4顆?；罨^(guò)硫酸鹽氧化去除水中四環(huán)素為探針?lè)磻?yīng),評(píng)價(jià)CoFe2O4顆粒的活化性能.結(jié)果表明,600℃焙燒溫度下制備出的固體顆粒,其活性較高,顆粒表面金屬離子浸出率較低;優(yōu)化溫度下制備的CoFe2O4顆粒在較寬的pH值范圍(4.4～9.0)內(nèi)均具有較高活性;控制實(shí)驗(yàn)條件PDS01g/L,CoFe2O41g/L,TCH050mg/L,20℃,pH04.4,反應(yīng)4h后TCH去除率達(dá)到82.0%.CoFe2O4顆粒循環(huán)重復(fù)利用10次后仍保持較高的活性和結(jié)構(gòu)穩(wěn)定性,而且因其特殊的磁性能便于回收利用.

非均相活化；硫酸根自由基；磁性納米CoFe2O4顆粒；重復(fù)循環(huán)利用；四環(huán)素

基于硫酸根自由基的新型高級(jí)氧化技術(shù)(SR- AOPs)在處理難降解有機(jī)廢水方面具有十分可觀的應(yīng)用前景.過(guò)硫酸鹽常溫下比較穩(wěn)定,但在某些特定條件下被激活產(chǎn)生強(qiáng)氧化性硫酸根自由基(SO4·-,氧化還原電位2.5～3.1V),理論上能夠氧化降解大部分有機(jī)污染物[1-4].常見的活化方式有過(guò)渡金屬離子(Fe2+、Co2+、Ag+等)活化[2,4-10],熱活化[11-17],紫外光照射活化[18-23]等.均相過(guò)渡金屬離子活化過(guò)硫酸鹽體系,常溫常壓下簡(jiǎn)單操作即可得顯著效果,因而應(yīng)用最廣泛,但均相體系也存在一些弊端[24-26]: (1)均相體系中低價(jià)態(tài)金屬離子如Fe2+易被迅速氧化從而喪失活性導(dǎo)致其利用率低,過(guò)量投加又會(huì)產(chǎn)生大量鐵污泥;(2)均相體系中金屬離子在中性和堿性條件下易沉淀從而降低活化效率,限制了體系pH值應(yīng)用范圍;(3)均相體系反應(yīng)后殘留溶液中金屬離子濃度過(guò)高,活化劑流失且難以回收利用,對(duì)環(huán)境造成二次污染.雖然制備固體活化劑將研究重點(diǎn)轉(zhuǎn)移至非均相體系能夠應(yīng)對(duì)均相體系的一些弊端,但常規(guī)活化劑固體顆粒仍然存在流失嚴(yán)重且難以回收的問(wèn)題,而且隨著反應(yīng)時(shí)間的延長(zhǎng)其自身結(jié)構(gòu)穩(wěn)定性容易被破壞進(jìn)而無(wú)法保證高效的活性.針對(duì)以上問(wèn)題,本文以軟磁性物質(zhì)CoFe2O4為切入點(diǎn),制備了具有一定磁性的納米CoFe2O4顆粒,利用其磁性能解決活化劑流失及難以回收的難題;以活化過(guò)硫酸鹽體系中四環(huán)素(TCH)的氧化去除為探針?lè)磻?yīng),研究非均相磁性納米CoFe2O4顆粒的活性,以期擴(kuò)寬其pH值應(yīng)用范圍;最后,將活化劑顆粒進(jìn)行重復(fù)利用,考察其活化性能的穩(wěn)定性及其自身結(jié)構(gòu)穩(wěn)定性.

1 材料與方法

1.1 儀器與試劑

實(shí)驗(yàn)儀器:電子天平(上海舜宇恒平FA1004型),恒溫水浴裝置(上海標(biāo)本76-Sa型),機(jī)械攪裝置(上海標(biāo)本JB90-SH型),電熱鼓風(fēng)干燥箱(北京永光明101-E型),程序升溫馬弗爐(合肥科晶KSL-1200X型),紫外可見分光光度計(jì)(上海舜宇恒平752型),原子吸收分光光度計(jì)(日本島津AA-6300C型),pH計(jì)(美國(guó)奧豪斯STARTER 3100型),超聲波清洗機(jī)(昆山超聲KQ5200DE型),真空干燥箱(上海博迅DZF-6050型).

實(shí)驗(yàn)試劑:過(guò)二硫酸鈉(PDS,Na2S2O8),鹽酸四環(huán)素(TCH,C22H24N2O8·HCl),硝酸鈷(Co(NO3)2·6H2O),硝酸鐵(Fe(NO3)3·9H2O),檸檬酸(CA,C6H8O7·H2O),氫氧化鈉(NaOH),濃硫酸(H2SO4),濃鹽酸(HCl)均為分析純;實(shí)驗(yàn)用水均采用超純水.

1.2 活化劑顆粒的制備

以檸檬酸(CA)絡(luò)合金屬離子的機(jī)理,采用溶膠-凝膠法[9,27-29]制備磁性納米CoFe2O4顆粒.首先,稱取定量的硝酸鈷和硝酸鐵于燒杯中,加入超純水混合均勻,保證混合溶液中鈷離子和鐵離子的物質(zhì)的量比為1:2;其次,將裝有混合溶液的燒杯放入60℃水浴中劇烈攪拌2h;接著,加入定量CA,保證其物質(zhì)的量濃度等同于金屬離子物質(zhì)的量濃度之和,繼續(xù)在60℃水浴中劇烈攪拌2h;然后,將所得透明溶膠轉(zhuǎn)入90℃恒溫干燥箱中,數(shù)小時(shí)后得到蜂窩狀的前驅(qū)物;最后,將前驅(qū)物研磨成粉體,置于陶瓷坩堝中,于馬弗爐中特定溫度下焙燒2h,即得活化劑顆粒樣品.

1.3 活化劑顆粒的表征

采用荷蘭FEI XL-30掃描電子顯微鏡(SEM)分析測(cè)定固體樣品的表面形貌和顆粒分布狀態(tài).采用北京普析XD6X射線衍射儀(XRD)表征分析固體樣品的物相組成.采用美國(guó)Nicolet 500傅里葉變換紅外光譜儀(FT-IR)對(duì)固體樣品的官能團(tuán)進(jìn)行分析.采用美國(guó)LakeShore 7410VSM振動(dòng)樣品磁強(qiáng)計(jì)測(cè)定固體樣品的H-M磁滯回線,分析其磁性能.

1.4 活化劑顆粒的活性評(píng)價(jià)

以活化過(guò)硫酸鹽體系中TCH的氧化去除為探針?lè)磻?yīng),評(píng)價(jià)固體顆粒的活性,實(shí)驗(yàn)裝置如圖1所示.首先,向300mL圓柱形玻璃容器中加入一定濃度的TCH溶液;其次,將玻璃容器放入20℃恒溫水浴裝置中,300r/min攪拌混勻,測(cè)定TCH濃度作為初始值;然后,向反應(yīng)器中加入定量磁性納米CoFe2O4顆粒和定量PDS溶液,計(jì)時(shí)開始,每隔一定時(shí)間取樣,立即用0.22 μm微孔濾膜過(guò)濾并用紫外分光光度計(jì)于358nm波長(zhǎng)處測(cè)定濾液中TCH濃度[3](5～50mg/L濃度范圍內(nèi)的TCH溶液對(duì)吸光度值的線性擬合系數(shù)高達(dá)0.999).考察溶液初始pH值(pH0)影響時(shí),用0.01mol/L H2SO4溶液和0.1mol/L NaOH溶液調(diào)節(jié)溶液pH值;如無(wú)特殊說(shuō)明,其它實(shí)驗(yàn)均未調(diào)pH值.實(shí)驗(yàn)中50mg/L TCH溶液的自然pH值約為4.4.每組實(shí)驗(yàn)至少設(shè)置3個(gè)平行實(shí)驗(yàn),結(jié)果取平均值.

圖1 實(shí)驗(yàn)裝置

1.5 活化劑顆粒的穩(wěn)定性評(píng)價(jià)

為了考察活化劑顆粒的穩(wěn)定性,采用原子吸收分光光度法對(duì)顆粒中的Fe/Co浸出量進(jìn)行測(cè)定分析,并進(jìn)行循環(huán)重復(fù)利用實(shí)驗(yàn).

重復(fù)利用實(shí)驗(yàn)中,活化劑顆粒的清洗方法為:上一批次實(shí)驗(yàn)反應(yīng)后,用磁鐵將顆粒溶液進(jìn)行固液分離,收集固體顆粒并將其浸沒(méi)在定量超純水中邊攪拌邊超聲進(jìn)行清洗,然后靜置磁分離,測(cè)定上清液中TCH濃度;反復(fù)清洗直至上清液中檢測(cè)不到TCH含量,之后將磁分離后的顆粒60℃真空干燥處理,干燥后的顆粒經(jīng)研磨后進(jìn)入下一批次重復(fù)反應(yīng)過(guò)程.

2 結(jié)果與討論

2.1 活化劑顆粒的制備

2.1.1 活化劑顆粒樣品的物相分析(XRD) 采用溶膠-凝膠法在不同焙燒溫度(300～800℃)下制備了一系列活化劑顆粒,其XRD圖譜如圖2所示.活化劑樣品的特征峰出現(xiàn)在衍射角2為18.3°, 30.1°, 35.4°, 37.1°, 43.1°, 53.4°, 56.9°, 62.6°, 74.0°和75.0°處,分別對(duì)應(yīng)尖晶石型CoFe2O4的(111), (220), (311), (222), (400), (422), (511), (440), (620)和(533)晶面(標(biāo)準(zhǔn)卡片JCPDS:22-1086)[28].300℃樣品的XRD圖譜相應(yīng)特征峰不明顯,表明活化劑結(jié)晶較差,CoFe2O4成型較差;隨著焙燒溫度(400～800℃)的升高,特征峰變明顯且更強(qiáng)更窄,活化劑結(jié)晶性提高,CoFe2O4成型較好.除300℃外,其它溫度下活化劑樣品XRD圖譜與標(biāo)準(zhǔn)卡片JCPDS:22-1086(Cobalt iron oxide CoFe2O4)相符合,且無(wú)其它雜峰,表明成功制備出了CoFe2O4,且純度較高.

圖2 不同焙燒溫度下活化劑的XRD圖譜

2.1.2 焙燒溫度對(duì)活性和穩(wěn)定性的影響 將活化劑顆粒添加至活化PDS反應(yīng)體系中,分析TCH去除率來(lái)考察固體顆粒的活性,分析固體顆粒中金屬離子溶出量來(lái)考察固體顆粒的穩(wěn)定性.實(shí)驗(yàn)條件為PDS投加量(PDS0)0.5g/L,CoFe2O4投加量1g/L,TCH初始濃度(TCH0)50mg/L.

將不同焙燒溫度(300～800℃)下制備的一系列活化劑顆粒投加至PDS體系中,液相中TCH的去除情況見圖3a.300～500℃焙燒溫度下制備的活化劑在PDS體系中對(duì)TCH的去除效果明顯高于600～800℃系列活化劑,這可能得益于其對(duì)TCH的吸附性能(圖4).如圖4所示,活化劑對(duì)TCH的吸附性能隨著焙燒溫度的提高而逐漸減弱;300℃系列活化劑對(duì)TCH的吸附性最強(qiáng),高達(dá)55.9%;600～800℃系列活化劑對(duì)TCH的吸附效率區(qū)別不大,均低于4.0%.因此,PDS/ CoFe2O4體系中液相TCH濃度的降低,一方面是由于活化劑顆粒的吸附作用使得TCH從液相轉(zhuǎn)移至固體活化劑表面,另一方面是由于活化劑表面金屬離子活化過(guò)硫酸鹽產(chǎn)生強(qiáng)氧化性硫酸根自由基導(dǎo)致TCH被氧化去除[4,28,30-32](式1);其中,后者對(duì)TCH去除的貢獻(xiàn)程度被用來(lái)評(píng)價(jià)活化劑顆粒對(duì)PDS的活化性能.

式中:M代表金屬元素.

如表1所示,以相同反應(yīng)時(shí)間內(nèi)TCH整體去除率與吸附率的差值(D(去除-吸附))為指標(biāo)來(lái)評(píng)估活化性能,則600℃焙燒溫度下制備的活化劑顆粒具有較高的活性,700℃僅次之,其次是800,500,400, 300℃.

此外,為了考察CoFe2O4系列活化劑在反應(yīng)體系中的穩(wěn)定性,本文對(duì)PDS/CoFe2O4體系中活化劑金屬離子溶出情況進(jìn)行研究,結(jié)果如圖3b所示.在相同實(shí)驗(yàn)條件下,添加相同濃度(1g/L)活化劑顆粒,在活化過(guò)硫酸鹽體系下歷經(jīng)4h反應(yīng)后,300℃活化劑中金屬離子溶出量最多,其中鐵離子和鈷離子濃度分別為2.09和4.02mg/L.由于溶液中過(guò)渡金屬離子對(duì)過(guò)硫酸鹽有顯著的活化作用[1,5,33-34],過(guò)多金屬離子的溶出會(huì)加重PDS/CoFe2O4體系中均相反應(yīng)的貢獻(xiàn),暴露均相體系的弊端.300℃活化劑活化過(guò)硫酸鹽體系中,反應(yīng)前30min內(nèi)液相中TCH濃度的迅速降低,除了活化劑的吸附作用外,活化劑中溶出金屬離子活化過(guò)硫酸鹽導(dǎo)致的均相反應(yīng)同樣起到重要的促進(jìn)作用.焙燒溫度增至600℃時(shí)制備的活化劑,在活化過(guò)硫酸鹽體系下歷經(jīng)4h反應(yīng)后其溶出的金屬離子量明顯降低,其中鐵離子和鈷離子濃度分別為0.27和0.26mg/L,合計(jì)占固體活化劑總質(zhì)量的0.053%.

圖4 不同焙燒溫度下制備的活化劑樣品對(duì)TCH的吸附

表1 不同活化劑樣品在4h反應(yīng)時(shí)間內(nèi)對(duì)TCH的吸附情況(僅活化劑體系)和去除情況(PDS/活化劑體系)

綜上所述,為了減弱均相反應(yīng)的貢獻(xiàn)和活化劑的穩(wěn)定性考慮,并結(jié)合其對(duì)PDS的活化性能,600℃是采用溶膠-凝膠法制備CoFe2O4活化劑最適宜的焙燒溫度.

2.2 CoFe2O4活化劑的表征

2.2.1 官能團(tuán)分析(FT-IR)和元素成分分析 圖5顯示了活化劑前驅(qū)物(焙燒前)和CoFe2O4活化劑(焙燒后)的FT-IR圖譜.前驅(qū)物圖譜中比較明顯的吸收峰出現(xiàn)在1617和1437cm-1處,分別對(duì)應(yīng)前驅(qū)物檸檬酸鹽中COO-的非對(duì)稱和對(duì)稱伸縮振動(dòng)[9,35].另外,前驅(qū)物中硝酸鹽成分的NO3-常常出現(xiàn)在FT-IR圖譜的1430～1340cm-1峰位置處[9,36],在圖中也有所體現(xiàn).活化劑圖譜中577cm-1處有一明顯的吸收峰,對(duì)應(yīng)的是尖晶石型FeO6結(jié)構(gòu)的四面體位置金屬內(nèi)在伸縮振動(dòng)[36],說(shuō)明CoFe2O4的形成.CoFe2O4活化劑圖譜中1617和1437cm-1吸收峰的消失,表明在600℃焙燒溫度足夠保證活化劑前驅(qū)物焙燒過(guò)程中有機(jī)殘留物的完全去除.

圖5 CoFe2O4活化劑600℃焙燒前和焙燒后樣品的FT-IR圖譜

為了分析活化劑顆粒的元素成分,將定量顆粒樣品完全溶解于熱的濃鹽酸中,測(cè)定溶液中Fe和Co含量,分析兩者的物質(zhì)的量濃度比.結(jié)果表明,元素Fe和Co的物質(zhì)的量濃度比值為1.92,非常接近CoFe2O4成分的理論值,說(shuō)明制備的固體顆粒中CoFe2O4成分較高.

2.2.2 表面形貌(SEM)和磁性能(H-M磁滯回線)分析 圖6a顯示了600℃焙燒溫度下制備的CoFe2O4活化劑樣品的SEM圖.活化劑樣品表面形貌均一,為球形納米顆粒,伴有輕度團(tuán)聚現(xiàn)象.活化劑表面的團(tuán)聚現(xiàn)象可能與活化劑強(qiáng)磁性(圖6b)有關(guān).

由圖6b可知,活化劑樣品具有很好的磁性能,其飽和磁化強(qiáng)度為53.7emu/g,表明活化劑樣品可以通過(guò)外加磁場(chǎng)進(jìn)行回收再利用,還可實(shí)現(xiàn)活化劑顆粒的快速固定(如固定式反應(yīng)床)并避免活化劑的流失,具有十分可觀的應(yīng)用前景.

2.3 磁性納米CoFe2O4活化PDS氧化去除TCH的情況

控制實(shí)驗(yàn)條件為PDS01g/L,CoFe2O41g/L, TCH050mg/L,20℃,pH07.0;不同體系下TCH的去除情況如圖7所示.向TCH溶液中單獨(dú)加入CoFe2O4(僅CoFe2O4體系),4h內(nèi)TCH去除率約為4.5%,說(shuō)明活化劑顆粒對(duì)TCH具有一定的吸附能力.向TCH溶液中單獨(dú)加入PDS(僅PDS體系),4h內(nèi)溶液中TCH濃度幾乎無(wú)降低,說(shuō)明PDS自身的氧化性(0=2.01V)不足以氧化去除TCH[37].但當(dāng)TCH反應(yīng)體系中CoFe2O4和PDS同時(shí)存在時(shí),溶液中TCH的去除率達(dá)到72.6%,說(shuō)明CoFe2O4對(duì)PDS具有很好的活化性能.

由于CoFe2O4活化劑顆粒在反應(yīng)過(guò)程中有金屬離子的溶出,本文研究了活化劑溶出金屬離子活化PDS的均相反應(yīng)體系中TCH去除情況,同等條件下將活化劑浸泡于TCH溶液中4h后分離出活化劑,向剩余溶液中投加PDS,實(shí)驗(yàn)反應(yīng)4h的結(jié)果如圖7中“PDS/Co-Fe”曲線所示.TCH的去除率為15.0%,可見溶出金屬離子活化PDS的均相反應(yīng)對(duì)TCH氧化去除的貢獻(xiàn)很少,這也間接證明了CoFe2O4納米顆粒在活化PDS過(guò)程中主要以活化劑表面金屬離子活化PDS的非均相反應(yīng)為主,本質(zhì)上區(qū)別于溶出金屬離子活化PDS的均相反應(yīng).

圖7 不同體系下TCH去除情況

控制實(shí)驗(yàn)條件為PDS01g/L,CoFe2O41g/L, TCH050mg/L,20℃;不同初始pH值(pH0)條件下PDS/CoFe2O4體系中TCH的去除情況如圖8所示.隨著pH0的升高,TCH的去除率均逐漸降低.當(dāng)溶液pH0為4.4時(shí),反應(yīng)4h后TCH的去除率達(dá)到82.0%;當(dāng)溶液pH0為7.0時(shí),TCH的去除率下降至72.6%;繼續(xù)提高溶液pH0至9.0時(shí),TCH的去除率進(jìn)一步降低至60.0%.SO4?-在堿性條件下會(huì)與OH-反應(yīng)生成?OH自由基[1-2](式2),因此本實(shí)驗(yàn)所制備的CoFe2O4活化PDS體系即使在堿性條件下仍能保持較好的TCH去除效果.堿性條件下TCH去除效果有所下降,一方面是由于?OH自由基的氧化還原電位低于SO4?-自由基[38],另一方面可能是由于?OH半衰期短于SO4?-進(jìn)而無(wú)法完全遷移至TCH并與之發(fā)生有效接觸[39].整體來(lái)看,PDS/ CoFe2O4體系在較寬pH值范圍內(nèi)對(duì)TCH有很好的去除效果.

圖8 不同初始pH值條件下PDS/CoFe2O4體系中TCH的去除情況

Fig.8 The TCH removal in PDS/CoFe2O4 systems with different initial pH

2.4 磁性納米CoFe2O4活化劑的重復(fù)利用和金屬離子溶出情況

為了評(píng)價(jià)CoFe2O4活化劑的穩(wěn)定性,將CoFe2O4活化劑進(jìn)行清洗循環(huán)使用,重復(fù)利用數(shù)次后TCH的去除情況,活化劑浸出金屬離子情況和活化劑物相分析如圖9和圖10所示.試驗(yàn)條件為PDS01g/L, CoFe2O41g/L,TCH050mg/L,20℃.

采用新活化劑投入PDS體系時(shí),反應(yīng)4h后TCH的去除率為82.0%;活化劑循環(huán)利用10次過(guò)程中, TCH的去除率浮動(dòng)較小,平均值為81.0%;活化劑在第10次循環(huán)利用過(guò)程中,依舊保持較高的TCH去除率(80.1%),這表明CoFe2O4活化劑對(duì)過(guò)硫酸鹽保持較高且穩(wěn)定的活化性能.在活化劑重復(fù)利用10次過(guò)程中,反應(yīng)4h后從活化劑中溶出的Fe和Co離子濃度平均值分別為0.226和0.222mg/L,溶出金屬離子含量占活化劑的質(zhì)量百分比約為0.0448%,這極小的溶出率表明所制備的CoFe2O4活化劑具有很好的穩(wěn)定性,這可能與穩(wěn)定的CoFe2O4反尖晶石結(jié)構(gòu)有關(guān).圖10顯示了循環(huán)數(shù)次后活化劑的XRD圖譜和FT-IR圖譜,表明活化劑循環(huán)利用10次后依舊保持較好的反尖晶石結(jié)構(gòu),也驗(yàn)證了所制備CoFe2O4活化劑的結(jié)構(gòu)穩(wěn)定性.

活化劑在活化PDS氧化去除TCH的體系中溶出的金屬離子濃度極小,而且重復(fù)利用10次后仍有較好的TCH去除效果,說(shuō)明所制備的CoFe2O4具有穩(wěn)定的活性,可重復(fù)使用.

3 結(jié)論

3.1 采用溶膠-凝膠法成功制備了磁性納米CoFe2O4顆粒.600℃是溶膠-凝膠法制備CoFe2O4活化劑最適宜的焙燒溫度.

3.2 將制備的磁性納米CoFe2O4顆粒應(yīng)用于活化PDS體系中,控制實(shí)驗(yàn)條件PDS01g/L,CoFe2O41g/L,TCH050mg/L,20℃,pH04.4,反應(yīng)4h后TCH去除率達(dá)到82.0%.pH0對(duì)CoFe2O4活化性能有影響,CoFe2O4活化劑在較寬pH值范圍(pH值4.4～9.0)內(nèi)對(duì)PDS保持較好的活性.

3.3 磁性納米CoFe2O4顆粒在活化過(guò)硫酸鹽體系中浸出金屬離子較少,占活化劑總重的0.0448%.整個(gè)反應(yīng)過(guò)程以活化劑表面金屬離子活化過(guò)硫酸鹽的非均相反應(yīng)為主,區(qū)別于活化劑浸出金屬離子活化過(guò)硫酸鹽的均相反應(yīng).

3.4 磁性納米CoFe2O4活化劑重復(fù)利用10次后,依舊保持較高的活性和較高的結(jié)構(gòu)穩(wěn)定性,可以重復(fù)利用.

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Preparation and activity evaluation of heterogeneous magnetic nano-CoFe2O4activators.

LIU Jia-lu1*, ZHANG Feng-jun2, PENG Xin-jing3

(1.China Nuclear Power Operation Technology Corporation, LTD., Wuhan 430223, China；2.Key Laboratory of Groundwater Resources and Environment, Ministry of Education, Jilin University, Changchun 130021, China；3.College of Environmental and Safety Engineering, Shenyang University of Chemical Technology, Shenyang 110142, China)., 2021,41(5)：2179～2186

The magnetic nanoscale cobalt ferrite (CoFe2O4) solid particles were prepared by the sol-gel method. These samples were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD), fourier transform infrared spectrometer (FT-IR) and vibrating sample magnetometer. The activity of CoFe2O4particles was evaluated with the removal experiments of tetracycline hydrochloride (TCH) in the activated persulfate oxidation system. The results showed that the particles calcined at 600℃ had the higher activity and lower metal ion leaching rate on the particle surface. The CoFe2O4particles prepared at the optimized temperature had high activity in a wide pH range (4.4～9.0) in activated persulfate oxidation system. The TCH removal efficiency reached 82.0% after 4 hours of reaction with the experimental conditions of PDS01g/L, CoFe2O41g/L, TCH050mg/L, 20℃, pH04.4. These particles still maintained high activity and structural stability after 10 cycles of reuse, and could be easily recycled due to its special magnetic properties.

heterogeneous activation；sulfate radical；magnetic nano-CoFe2O4particles；recycle；tetracycline

X703

A

1000-6923(2021)05-2179-08

劉佳露(1990-),女,河南郟縣人,博士,主要從事污水處理技術(shù)及電廠化學(xué)防腐技術(shù)的研究.發(fā)表論文5篇.

2020-09-27

* 責(zé)任作者, 工程師, liujialusmile@163.com