
活性炭吸附在幾(ji)種土壤中(zhong)
活性炭吸(xi)附(fu)在幾種(zhong)(zhong)土壤(rang)(rang)中(zhong),在土壤(rang)(rang)污染(ran)的(de)(de)情況下,土壤(rang)(rang)改良劑可用(yong)于(yu)固定有機污染(ran)物(wu),同時(shi)保(bao)持土壤(rang)(rang)功能,活性(xing)炭是一種(zhong)(zhong)有前(qian)景的(de)(de)土壤(rang)(rang)修復材料(liao)。在本期實驗(yan)中(zhong),菲烯(xi)(Phe)用(yong)于(yu)污染(ran)土壤(rang)(rang)的(de)(de)污染(ran)物(wu),我們(men)研(yan)(yan)究了(le)三種(zhong)(zhong)活性(xing)炭研(yan)(yan)究了(le)三種(zhong)(zhong)活性(xing)炭對(dui)三種(zhong)(zhong)不同基質、兩種(zhong)(zhong)農業表土和(he)純砂的(de)(de)影響(xiang)。我們(men)對(dui)土壤(rang)(rang)性(xing)質的(de)(de)變化、菲律賓的(de)(de)吸(xi)附(fu)-解吸(xi)和(he)菲律賓在所有治(zhi)療中(zhong)的(de)(de)礦化進行了(le)評估。
石油(you)碳(tan)氫化合物(wu)(wu)(wu)(wu)污染是(shi)(shi)土壤(rang)(rang)(rang)和(he)沉積物(wu)(wu)(wu)(wu)中(zhong)(zhong)*常見的(de)(de)(de)問(wen)題之一。菲(fei)律(lv)賓是(shi)(shi)一種(zhong)廣(guang)泛存(cun)在的(de)(de)(de)三環(huan)芳烴(jing),存(cun)在時間長,難以從環(huan)境中(zhong)(zhong)去除。活(huo)性(xing)(xing)(xing)(xing)炭吸附是(shi)(shi)控制(zhi)土壤(rang)(rang)(rang)和(he)水生系(xi)統(tong)中(zhong)(zhong)有機(ji)污染物(wu)(wu)(wu)(wu)流動(dong)性(xing)(xing)(xing)(xing)、可(ke)用(yong)性(xing)(xing)(xing)(xing)和(he)目的(de)(de)(de)地的(de)(de)(de)關鍵過(guo)程。多(duo)環(huan)芳烴(jing)的(de)(de)(de)吸附行為主要由(you)土壤(rang)(rang)(rang)有機(ji)質含(han)量調節(jie),土壤(rang)(rang)(rang)有機(ji)質是(shi)(shi)一種(zhong)通過(guo)含(han)碳(tan)產品(pin)修復的(de)(de)(de)參數。在過(guo)去的(de)(de)(de)幾十年里,人們努力探(tan)索和(he)生產新材料作(zuo)為一種(zhong)有效、低成(cheng)本的(de)(de)(de)土壤(rang)(rang)(rang)修復工具(ju),并深入研究(jiu)了活(huo)性(xing)(xing)(xing)(xing)炭在土壤(rang)(rang)(rang)中(zhong)(zhong)的(de)(de)(de)應(ying)用(yong)。活(huo)性(xing)(xing)(xing)(xing)炭是(shi)(shi)一種(zhong)富含(han)碳(tan)的(de)(de)(de)固體有機(ji)物(wu)(wu)(wu)(wu)熱(re)分解(jie)(jie)產物(wu)(wu)(wu)(wu)。熱(re)解(jie)(jie)有機(ji)物(wu)(wu)(wu)(wu)(木(mu)炭、生物(wu)(wu)(wu)(wu)炭、活(huo)性(xing)(xing)(xing)(xing)炭)的(de)(de)(de)行為明顯不(bu)同于土壤(rang)(rang)(rang)中(zhong)(zhong)所含(han)的(de)(de)(de)無熱(re)原有機(ji)物(wu)(wu)(wu)(wu)。活(huo)性(xing)(xing)(xing)(xing)炭的(de)(de)(de)強吸附性(xing)(xing)(xing)(xing)能(neng)可(ke)以通過(guo)改(gai)變土壤(rang)(rang)(rang)性(xing)(xing)(xing)(xing)質來調節(jie)土壤(rang)(rang)(rang)中(zhong)(zhong)芳烴(jing)的(de)(de)(de)降解(jie)(jie)過(guo)程,但也可(ke)以通過(guo)降低有機(ji)污染物(wu)(wu)(wu)(wu)的(de)(de)(de)可(ke)用(yong)性(xing)(xing)(xing)(xing)來調節(jie)。
土(tu)壤(rang)、沙(sha)(sha)子和活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)的(de)來(lai)(lai)源來(lai)(lai)自(zi)兩個農田(土(tu)壤(rang)1、土(tu)壤(rang)2)。沙(sha)(sha)子用(yong)10%HCl洗滌40-100μm低(di)鐵砂粒度(du),然后(hou)用(yong)去(qu)離子水沖洗10次,直到(dao)pH上升并(bing)穩(wen)定到(dao)5.5。三種來(lai)(lai)自(zi)不同來(lai)(lai)源的(de)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)用(yong)于實(shi)驗:(1)木質活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(AC(2)根系(xi)活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(AC和(3)農作物活(huo)(huo)性(xing)(xing)(xing)炭(tan)(tan)(AC3)。
土壤修復的方法
將(jiang)(jiang)活性炭(tan)(尺寸<1mm)以(yi)1%(w/w)的比率摻入(ru)測試的土壤(rang)和沙子中,這(zhe)是一個模(mo)擬自然環境的修復(fu)過程,考慮(lv)到30 cm的土壤(rang)深度和約1.6t m-3的土壤(rang)密度。將(jiang)(jiang)混合物均(jun)化后,將(jiang)(jiang)每個樣品潤濕至60%的保水能力(li),并在室溫(20-25℃)下(xia)在聚乙烯袋中平衡15天(tian)。所有程序和實驗(基本表征(zheng),批(pi)次相(xiang)互作用和土壤(rang)培養(yang))進(jin)行3-4次重復(fu)。
菲的吸附實驗
在(zai)玻璃(li)離(li)心(xin)管和7ml不同(tong)濃(nong)度的(de)(de)菲烯溶液(ye)(ye)中(zhong)(zhong)放入0.7g摻入活性炭的(de)(de)干燥土壤。通(tong)過(guo)在(zai)10mm CaCl 2和1.5的(de)(de)背景溶液(ye)(ye)中(zhong)(zhong)保持乙(yi)醇的(de)(de)比例<0.1%,將試(shi)管在(zai)頂置振蕩(dang)器(qi)中(zhong)(zhong)以100rpm搖(yao)動24小時,然后將它(ta)們以2700g離(li)心(xin)15分(fen)(fen)鐘,取1ml上清(qing)液(ye)(ye)的(de)(de)等(deng)分(fen)(fen)試(shi)樣。在(zai)β計數(shu)器(qi)中(zhong)(zhong)通(tong)過(guo)液(ye)(ye)體(ti)閃爍計數(shu)進行處(chu)理和分(fen)(fen)析,并在(zai)相互作用的(de)(de)7,24和48小時取上清(qing)液(ye)(ye)的(de)(de)等(deng)分(fen)(fen)試(shi)樣。
菲的解吸實驗
對于該實(shi)(shi)驗,我們選擇在(zai)相互作用后從吸附實(shi)(shi)驗中(zhong)獲取活性炭土(tu)(tu)壤(rang)菲(fei)的樣品。我們在(zai)吸附實(shi)(shi)驗中(zhong)提取了保留在(zai)土(tu)(tu)壤(rang)中(zhong)的菲(fei),劑量為1μg菲(fei)g-1土(tu)(tu)壤(rang)有六個表示(shi)。
熱化(hua)合物在高重力下改性
高(gao)重力環境下活性(xing)(xing)炭(tan)的熱化合(he)物改(gai)性(xing)(xing)。將100g以活性(xing)(xing)炭(tan)為(wei)填料層,9000r/min速(su)度(du)(du)操作300分(fen)鐘,99%氮氣通過入口(kou)。活性(xing)(xing)炭(tan)表(biao)示活性(xing)(xing)炭(tan)-RPB-N。原始活性(xing)(xing)炭(tan)和活性(xing)(xing)炭(tan)-RPB-N用(yong)1mol·L-1HNO 3在70攝氏度(du)(du),流速(su)40L·min-1,轉速(su)36.3Hz改(gai)性(xing)(xing)。處理(li)后,用(yong)去離子水(shui)沖洗后,將兩個樣(yang)品在110℃的真空烘(hong)箱中(zhong)干燥24小(xiao)時,并分(fen)別表(biao)示為(wei)活性(xing)(xing)炭(tan)-RPB-HNO和活性(xing)(xing)炭(tan)-RPB-N-HNO。
在(zai)高重力物理(li)改性過(guo)程中,氮(dan)(dan)分(fen)布不再是從頂(ding)部到(dao)(dao)底(di)部的(de)(de)單一流(liu)動,而(er)是通(tong)過(guo)各個方向的(de)(de)對流(liu)輸送(song)到(dao)(dao)活性炭。與(yu)活性炭接觸(chu)后(hou),氮(dan)(dan)產生新的(de)(de)微孔(kong),挖掘現有的(de)(de)吸附通(tong)道。因(yin)此,它(ta)增加了它(ta)們的(de)(de)表面積和孔(kong)容(rong)量。簡化原理(li)圖如圖1所示。
氮和硝酸改性在正常和高重力環境中(zhong)的示意圖。
實驗研(yan)究活性(xing)炭吸附性(xing)能
研究了活性炭在(zai)吸附(fu)(fu)(fu)柱中吸附(fu)(fu)(fu)甲(jia)苯(ben)(ben)(ben)的(de)(de)(de)(de)(de)能力。活性炭用量為10g,氣(qi)(qi)體(ti)發生(sheng)器產(chan)生(sheng)吸附(fu)(fu)(fu)質甲(jia)苯(ben)(ben)(ben)氣(qi)(qi)體(ti)。活性炭吸附(fu)(fu)(fu)性能的(de)(de)(de)(de)(de)數據是通(tong)過(guo)(guo)測(ce)量吸附(fu)(fu)(fu)前(qian)后(hou)甲(jia)苯(ben)(ben)(ben)的(de)(de)(de)(de)(de)濃度來獲得的(de)(de)(de)(de)(de)。實(shi)驗吸附(fu)(fu)(fu)裝置的(de)(de)(de)(de)(de)流(liu)程圖如圖2所示。甲(jia)苯(ben)(ben)(ben)氣(qi)(qi)體(ti)與氮氣(qi)(qi)混合(he),然后(hou)吸附(fu)(fu)(fu)在(zai)恒溫吸附(fu)(fu)(fu)塔(ta)中。通(tong)過(guo)(guo)在(zai)線(xian)FID檢測(ce)器測(ce)量吸附(fu)(fu)(fu)前(qian)后(hou)的(de)(de)(de)(de)(de)甲(jia)苯(ben)(ben)(ben)含(han)量,并通(tong)過(guo)(guo)流(liu)量計(ji)控(kong)制(zhi)甲(jia)苯(ben)(ben)(ben)流(liu)量。當(dang)脫氣(qi)(qi)和(he)入口(kou)濃度在(zai)30分(fen)鐘內保(bao)持一致時,認為吸附(fu)(fu)(fu)平衡已經達(da)到(dao)。通(tong)過(guo)(guo)廢氣(qi)(qi)出口(kou)排出吸附(fu)(fu)(fu)氣(qi)(qi)體(ti)。
實驗吸附流動圖。
幾種活性炭對甲苯的吸附性能(neng)比較(jiao)
不(bu)(bu)(bu)同活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)上甲苯的(de)(de)穿透曲線和吸(xi)附(fu)(fu)等溫曲線如圖3所示(shi)和4所示(shi)。不(bu)(bu)(bu)同活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)(de)吸(xi)附(fu)(fu)率(lv)從高到低依(yi)次(ci)為:活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-HNO>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N>活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-N>原始活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)。吸(xi)附(fu)(fu)率(lv)越(yue)大(da),滲透時間(jian)(jian)(jian)越(yue)長,這與活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)(de)復雜孔(kong)徑分(fen)布和表(biao)(biao)面官能(neng)團的(de)(de)數(shu)量有(you)關。高溫氮氣中活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)(de)微孔(kong)體積(ji)(ji)增(zeng)(zeng)(zeng)加(jia)(jia),增(zeng)(zeng)(zeng)加(jia)(jia)了(le)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)通道的(de)(de)內孔(kong)體積(ji)(ji)。在(zai)(zai)高重力(li)(li)氮氣環境中,不(bu)(bu)(bu)利于甲苯吸(xi)收的(de)(de)原始活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)(de)內部結構(gou)被重新分(fen)配并分(fen)裂成新的(de)(de)空(kong)間(jian)(jian)(jian)結構(gou),進一步增(zeng)(zeng)(zeng)加(jia)(jia)了(le)突破(po)時間(jian)(jian)(jian)。HNO 在(zai)(zai)高重力(li)(li)環境下,3處理(li)(li)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)(de)突破(po)時間(jian)(jian)(jian)大(da)于改(gai)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)HNO 改(gai)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)浸泡。這是因為HNO 在(zai)(zai)分(fen)散的(de)(de)小液滴(di)中,增(zeng)(zeng)(zeng)加(jia)(jia)了(le)與活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)表(biao)(biao)面和內部接觸的(de)(de)可能(neng)性(xing)(xing)(xing)(xing)(xing)(xing)(xing),進而(er)增(zeng)(zeng)(zeng)加(jia)(jia)了(le)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)上含(han)氧(yang)官能(neng)團的(de)(de)負荷,提高了(le)其吸(xi)附(fu)(fu)效(xiao)率(lv)。在(zai)(zai)重力(li)(li)作用下,復合改(gai)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)活(huo)(huo)(huo)(huo)(huo)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)具有(you)較長的(de)(de)穿透時間(jian)(jian)(jian)和較大(da)的(de)(de)吸(xi)附(fu)(fu)率(lv),因為物理(li)(li)改(gai)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)加(jia)(jia)了(le)比表(biao)(biao)面積(ji)(ji),增(zeng)(zeng)(zeng)加(jia)(jia)了(le)孔(kong)體積(ji)(ji)分(fen)布,而(er)化學改(gai)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)加(jia)(jia)了(le)表(biao)(biao)面氧(yang)基團的(de)(de)數(shu)量。反過來,這些特性(xing)(xing)(xing)(xing)(xing)(xing)(xing)增(zeng)(zeng)(zeng)強了(le)吸(xi)附(fu)(fu)性(xing)(xing)(xing)(xing)(xing)(xing)(xing)。
活性炭的(de)突破曲線。
等溫曲線吸附活性炭(tan)。
活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)在(zai)常規(gui)和高(gao)重力(li)(li)環境高(gao)重力(li)(li)環境下(xia)進行了物(wu)理、化學和化合(he)物(wu)改性(xing)(xing)(xing)(xing)。研究了甲(jia)苯(ben)在(zai)不同活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)上(shang)的(de)吸(xi)附。高(gao)重力(li)(li)化合(he)物(wu)改性(xing)(xing)(xing)(xing)活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)具有*大的(de)吸(xi)附率(lv)和容量。還發現,微孔結構(gou)在(zai)活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)吸(xi)附甲(jia)苯(ben)的(de)過程中起著主(zhu)導(dao)作用。由(you)于化合(he)物(wu)的(de)改性(xing)(xing)(xing)(xing),活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)的(de)優(you)異(yi)吸(xi)附能力(li)(li)增加(jia)了有效吸(xi)附位點的(de)數量。活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)-RPB-N-HNO上(shang)甲(jia)苯(ben)表面覆蓋率(lv)為51.67%。因此,活性(xing)(xing)(xing)(xing)炭(tan)(tan)(tan)在(zai)高(gao)重力(li)(li)下(xia)的(de)復合(he)改性(xing)(xing)(xing)(xing)可以大大提高(gao)吸(xi)附性(xing)(xing)(xing)(xing)能。
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