
活(huo)性炭吸附(fu)在幾種土壤中
活性炭吸附在幾種(zhong)土(tu)壤(rang)中,在土(tu)壤(rang)污染(ran)的(de)情況下,土(tu)壤(rang)改(gai)良(liang)劑(ji)可用于(yu)固定有(you)(you)機污染(ran)物,同時保持土(tu)壤(rang)功(gong)能,活(huo)性炭(tan)(tan)是(shi)一(yi)種(zhong)有(you)(you)前景(jing)的(de)土(tu)壤(rang)修復材(cai)料(liao)。在本期實驗(yan)中,菲(fei)烯(Phe)用于(yu)污染(ran)土(tu)壤(rang)的(de)污染(ran)物,我們(men)研究(jiu)了三(san)種(zhong)活(huo)性炭(tan)(tan)研究(jiu)了三(san)種(zhong)活(huo)性炭(tan)(tan)對三(san)種(zhong)不同基(ji)質、兩(liang)種(zhong)農業表土(tu)和(he)(he)純砂的(de)影響。我們(men)對土(tu)壤(rang)性質的(de)變化(hua)、菲(fei)律(lv)賓(bin)的(de)吸附-解吸和(he)(he)菲(fei)律(lv)賓(bin)在所有(you)(you)治療中的(de)礦(kuang)化(hua)進(jin)行了評估。
石油碳(tan)氫化合(he)物(wu)(wu)(wu)污(wu)染是(shi)土(tu)(tu)壤(rang)和沉積(ji)物(wu)(wu)(wu)中(zhong)*常(chang)見的(de)問題(ti)之一(yi)。菲(fei)律(lv)賓(bin)是(shi)一(yi)種(zhong)(zhong)廣泛存(cun)在(zai)(zai)的(de)三環芳(fang)烴(jing)(jing),存(cun)在(zai)(zai)時間長,難(nan)以從環境(jing)中(zhong)去除。活(huo)(huo)性(xing)(xing)炭(tan)(tan)吸附(fu)(fu)是(shi)控制土(tu)(tu)壤(rang)和水生(sheng)系統中(zhong)有(you)(you)機(ji)(ji)污(wu)染物(wu)(wu)(wu)流動性(xing)(xing)、可(ke)用(yong)性(xing)(xing)和目的(de)地的(de)關鍵過(guo)程(cheng)。多環芳(fang)烴(jing)(jing)的(de)吸附(fu)(fu)行為(wei)主要由土(tu)(tu)壤(rang)有(you)(you)機(ji)(ji)質(zhi)含量調(diao)節(jie),土(tu)(tu)壤(rang)有(you)(you)機(ji)(ji)質(zhi)是(shi)一(yi)種(zhong)(zhong)通過(guo)含碳(tan)產(chan)品修復的(de)參數。在(zai)(zai)過(guo)去的(de)幾十(shi)年里(li),人們努力探索和生(sheng)產(chan)新材料(liao)作(zuo)為(wei)一(yi)種(zhong)(zhong)有(you)(you)效、低成本的(de)土(tu)(tu)壤(rang)修復工具,并深(shen)入研究了(le)活(huo)(huo)性(xing)(xing)炭(tan)(tan)在(zai)(zai)土(tu)(tu)壤(rang)中(zhong)的(de)應(ying)用(yong)。活(huo)(huo)性(xing)(xing)炭(tan)(tan)是(shi)一(yi)種(zhong)(zhong)富含碳(tan)的(de)固體有(you)(you)機(ji)(ji)物(wu)(wu)(wu)熱分解產(chan)物(wu)(wu)(wu)。熱解有(you)(you)機(ji)(ji)物(wu)(wu)(wu)(木(mu)炭(tan)(tan)、生(sheng)物(wu)(wu)(wu)炭(tan)(tan)、活(huo)(huo)性(xing)(xing)炭(tan)(tan))的(de)行為(wei)明顯不同于土(tu)(tu)壤(rang)中(zhong)所含的(de)無(wu)熱原有(you)(you)機(ji)(ji)物(wu)(wu)(wu)。活(huo)(huo)性(xing)(xing)炭(tan)(tan)的(de)強吸附(fu)(fu)性(xing)(xing)能(neng)可(ke)以通過(guo)改變土(tu)(tu)壤(rang)性(xing)(xing)質(zhi)來(lai)(lai)調(diao)節(jie)土(tu)(tu)壤(rang)中(zhong)芳(fang)烴(jing)(jing)的(de)降(jiang)解過(guo)程(cheng),但也可(ke)以通過(guo)降(jiang)低有(you)(you)機(ji)(ji)污(wu)染物(wu)(wu)(wu)的(de)可(ke)用(yong)性(xing)(xing)來(lai)(lai)調(diao)節(jie)。
土壤(rang)、沙(sha)子和(he)活(huo)性(xing)(xing)(xing)炭(tan)的(de)來源(yuan)(yuan)來自(zi)兩個農田(土壤(rang)1、土壤(rang)2)。沙(sha)子用(yong)(yong)10%HCl洗滌40-100μm低鐵砂(sha)粒度,然后用(yong)(yong)去離(li)子水沖洗10次(ci),直到pH上升(sheng)并(bing)穩定到5.5。三(san)種(zhong)來自(zi)不同來源(yuan)(yuan)的(de)活(huo)性(xing)(xing)(xing)炭(tan)用(yong)(yong)于(yu)實驗:(1)木質活(huo)性(xing)(xing)(xing)炭(tan)(AC(2)根(gen)系活(huo)性(xing)(xing)(xing)炭(tan)(AC和(he)(3)農作物活(huo)性(xing)(xing)(xing)炭(tan)(AC3)。
土壤修復的方法
將活(huo)性炭(尺(chi)寸<1mm)以1%(w/w)的(de)比率摻入(ru)測試的(de)土壤(rang)和沙(sha)子中,這(zhe)是(shi)一個模(mo)擬自然環境的(de)修復(fu)過程(cheng),考(kao)慮(lv)到30 cm的(de)土壤(rang)深度和約1.6t m-3的(de)土壤(rang)密度。將混合物均化(hua)后,將每個樣品潤濕至60%的(de)保水能力,并在室(shi)溫(20-25℃)下在聚乙烯袋中平衡15天。所有程(cheng)序和實驗(基本表征(zheng),批次相互作(zuo)用和土壤(rang)培養)進行3-4次重復(fu)。
菲的吸附實驗
在(zai)玻(bo)璃(li)離心(xin)管和7ml不同(tong)濃(nong)度的(de)(de)(de)菲烯溶(rong)液(ye)中放入0.7g摻入活(huo)性炭的(de)(de)(de)干燥土壤。通(tong)過(guo)在(zai)10mm CaCl 2和1.5的(de)(de)(de)背景溶(rong)液(ye)中保持乙(yi)醇的(de)(de)(de)比例<0.1%,將試管在(zai)頂置振蕩器中以100rpm搖動24小時,然后將它們(men)以2700g離心(xin)15分鐘,取(qu)1ml上(shang)清(qing)液(ye)的(de)(de)(de)等分試樣(yang)。在(zai)β計數器中通(tong)過(guo)液(ye)體(ti)閃爍(shuo)計數進行處理(li)和分析,并在(zai)相互作用的(de)(de)(de)7,24和48小時取(qu)上(shang)清(qing)液(ye)的(de)(de)(de)等分試樣(yang)。
菲的解吸實驗
對于該實(shi)(shi)驗,我們(men)選(xuan)擇在相互作用后從吸(xi)附實(shi)(shi)驗中獲取活(huo)性炭土(tu)壤(rang)菲(fei)的樣品。我們(men)在吸(xi)附實(shi)(shi)驗中提取了保留在土(tu)壤(rang)中的菲(fei),劑量為1μg菲(fei)g-1土(tu)壤(rang)有六個(ge)表示。
熱化合物(wu)在(zai)高重(zhong)力下改(gai)性
高重力環境(jing)下活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)的熱化合物(wu)改性(xing)(xing)(xing)。將(jiang)100g以活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)為(wei)填(tian)料(liao)層,9000r/min速度(du)操作300分(fen)鐘,99%氮氣通過入口。活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)表(biao)示活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N。原始(shi)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)和(he)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N用(yong)1mol·L-1HNO 3在(zai)70攝氏度(du),流速40L·min-1,轉速36.3Hz改性(xing)(xing)(xing)。處理后,用(yong)去(qu)離子(zi)水(shui)沖(chong)洗(xi)后,將(jiang)兩個(ge)樣(yang)品(pin)在(zai)110℃的真空烘箱(xiang)中(zhong)干燥24小時,并分(fen)別表(biao)示為(wei)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-HNO和(he)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N-HNO。
在(zai)高重(zhong)力物理改性過程中,氮分布不再是從頂部(bu)(bu)到(dao)底部(bu)(bu)的單一流動,而是通過各個方向的對流輸送到(dao)活(huo)性炭(tan)。與活(huo)性炭(tan)接觸后,氮產生新的微孔,挖掘(jue)現有的吸附(fu)通道(dao)。因此(ci),它增加了它們的表面(mian)積和孔容量。簡化原理圖如圖1所(suo)示(shi)。
氮(dan)和硝酸改(gai)性在正(zheng)常和高(gao)重力(li)環境中的示意圖。
實驗研究活性炭吸附性能
研(yan)究了活(huo)性(xing)(xing)炭(tan)在(zai)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)柱中(zhong)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)甲(jia)(jia)苯(ben)的能(neng)力。活(huo)性(xing)(xing)炭(tan)用量(liang)為10g,氣(qi)(qi)(qi)體(ti)(ti)(ti)(ti)發生器產生吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)質甲(jia)(jia)苯(ben)氣(qi)(qi)(qi)體(ti)(ti)(ti)(ti)。活(huo)性(xing)(xing)炭(tan)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)性(xing)(xing)能(neng)的數據是通(tong)過(guo)(guo)測(ce)量(liang)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)前(qian)后(hou)甲(jia)(jia)苯(ben)的濃度來(lai)獲得的。實驗吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)裝置的流(liu)程圖如圖2所示。甲(jia)(jia)苯(ben)氣(qi)(qi)(qi)體(ti)(ti)(ti)(ti)與氮氣(qi)(qi)(qi)混(hun)合,然(ran)后(hou)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)在(zai)恒溫吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)塔中(zhong)。通(tong)過(guo)(guo)在(zai)線FID檢測(ce)器測(ce)量(liang)吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)前(qian)后(hou)的甲(jia)(jia)苯(ben)含量(liang),并通(tong)過(guo)(guo)流(liu)量(liang)計控制甲(jia)(jia)苯(ben)流(liu)量(liang)。當脫氣(qi)(qi)(qi)和入口(kou)濃度在(zai)30分(fen)鐘內保持一(yi)致時,認為吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)平衡已經達到。通(tong)過(guo)(guo)廢氣(qi)(qi)(qi)出口(kou)排出吸(xi)(xi)(xi)附(fu)(fu)(fu)(fu)氣(qi)(qi)(qi)體(ti)(ti)(ti)(ti)。
實驗(yan)吸附流動圖。
幾(ji)種(zhong)活性炭對甲苯的吸(xi)附性能比較
不同(tong)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)上甲苯(ben)(ben)的(de)穿透(tou)曲(qu)(qu)線和(he)吸(xi)附(fu)(fu)等溫(wen)曲(qu)(qu)線如圖3所(suo)示和(he)4所(suo)示。不同(tong)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)的(de)吸(xi)附(fu)(fu)率(lv)從高(gao)到(dao)低依次為:活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)-RPB-N-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)-RPB-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)-RPB-N>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)-N>原始活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)。吸(xi)附(fu)(fu)率(lv)越大(da),滲透(tou)時(shi)(shi)間(jian)越長,這(zhe)(zhe)與活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)的(de)復(fu)雜(za)孔徑分(fen)布和(he)表面官能(neng)團(tuan)的(de)數量(liang)有(you)關。高(gao)溫(wen)氮(dan)氣(qi)中活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)的(de)微孔體(ti)(ti)(ti)積(ji)(ji)增(zeng)(zeng)(zeng)(zeng)加(jia)(jia),增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)通(tong)道的(de)內(nei)(nei)孔體(ti)(ti)(ti)積(ji)(ji)。在高(gao)重(zhong)力氮(dan)氣(qi)環(huan)境中,不利于甲苯(ben)(ben)吸(xi)收的(de)原始活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)的(de)內(nei)(nei)部結構被重(zhong)新分(fen)配(pei)并(bing)分(fen)裂成新的(de)空(kong)間(jian)結構,進(jin)一步(bu)增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)突(tu)破時(shi)(shi)間(jian)。HNO 在高(gao)重(zhong)力環(huan)境下,3處理活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)的(de)突(tu)破時(shi)(shi)間(jian)大(da)于改性(xing)(xing)(xing)(xing)(xing)(xing)HNO 改性(xing)(xing)(xing)(xing)(xing)(xing)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)浸(jin)泡。這(zhe)(zhe)是因為HNO 在分(fen)散的(de)小液滴中,增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)與活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)表面和(he)內(nei)(nei)部接觸(chu)的(de)可能(neng)性(xing)(xing)(xing)(xing)(xing)(xing),進(jin)而(er)增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)上含(han)氧官能(neng)團(tuan)的(de)負荷(he),提高(gao)了(le)(le)(le)其吸(xi)附(fu)(fu)效率(lv)。在重(zhong)力作(zuo)用下,復(fu)合改性(xing)(xing)(xing)(xing)(xing)(xing)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)具有(you)較長的(de)穿透(tou)時(shi)(shi)間(jian)和(he)較大(da)的(de)吸(xi)附(fu)(fu)率(lv),因為物理改性(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)比表面積(ji)(ji),增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)孔體(ti)(ti)(ti)積(ji)(ji)分(fen)布,而(er)化學改性(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)(zeng)加(jia)(jia)了(le)(le)(le)表面氧基團(tuan)的(de)數量(liang)。反過(guo)來(lai),這(zhe)(zhe)些特性(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)(zeng)強了(le)(le)(le)吸(xi)附(fu)(fu)性(xing)(xing)(xing)(xing)(xing)(xing)。
活性炭的突破曲線。
等溫曲線吸附活性炭。
活(huo)性(xing)(xing)(xing)炭(tan)在(zai)常規(gui)和(he)高(gao)重(zhong)(zhong)力(li)(li)(li)環(huan)境高(gao)重(zhong)(zhong)力(li)(li)(li)環(huan)境下進行了(le)物理(li)、化(hua)學和(he)化(hua)合(he)物改性(xing)(xing)(xing)。研(yan)究了(le)甲苯(ben)在(zai)不同活(huo)性(xing)(xing)(xing)炭(tan)上的(de)吸(xi)(xi)(xi)附(fu)。高(gao)重(zhong)(zhong)力(li)(li)(li)化(hua)合(he)物改性(xing)(xing)(xing)活(huo)性(xing)(xing)(xing)炭(tan)具有(you)*大(da)(da)的(de)吸(xi)(xi)(xi)附(fu)率(lv)和(he)容(rong)量。還發(fa)現,微孔結構在(zai)活(huo)性(xing)(xing)(xing)炭(tan)吸(xi)(xi)(xi)附(fu)甲苯(ben)的(de)過程中起著主導作用。由于化(hua)合(he)物的(de)改性(xing)(xing)(xing),活(huo)性(xing)(xing)(xing)炭(tan)的(de)優異吸(xi)(xi)(xi)附(fu)能力(li)(li)(li)增(zeng)加了(le)有(you)效吸(xi)(xi)(xi)附(fu)位點的(de)數(shu)量。活(huo)性(xing)(xing)(xing)炭(tan)-RPB-N-HNO上甲苯(ben)表面覆蓋率(lv)為51.67%。因(yin)此,活(huo)性(xing)(xing)(xing)炭(tan)在(zai)高(gao)重(zhong)(zhong)力(li)(li)(li)下的(de)復合(he)改性(xing)(xing)(xing)可(ke)以大(da)(da)大(da)(da)提(ti)高(gao)吸(xi)(xi)(xi)附(fu)性(xing)(xing)(xing)能。
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