電解質和表面活性劑的復配作用

    總的(de)來(lai)說，存(cun)在于表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)溶(rong)(rong)液(ye)中(zhong)的(de)電(dian)解(jie)質(一般為(wei)無機鹽(yan))，往(wang)往(wang)使溶(rong)(rong)液(ye)的(de)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)提高。但對于離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)和非(fei)離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)情況有些不同。對于離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)，在溶(rong)(rong)液(ye)中(zhong)加入與表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)有相(xiang)同離(li)子(zi)(zi)(zi)的(de)無機鹽(yan)時(如RS04Na中(zhong)加入NaCl)，溶(rong)(rong)液(ye)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)提高，cmc下(xia)降。例如，對于cmc=1 X 10 -4mol／L的(de)離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)當反離(li)子(zi)(zi)(zi)(反離(li)子(zi)(zi)(zi)即與離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)帶(dai)有相(xiang)反電(dian)荷的(de)離(li)子(zi)(zi)(zi))總濃(nong)度(du)為(wei)0．1mol／L時，cmc則降低(di)到1．6×10-6mol／L，前后相(xiang)差100倍。另外，電(dian)解(jie)質還能顯著促進離(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)活(huo)(huo)性(xing)(xing)劑(ji)(ji)的(de)締合(he)，使其(qi)膠團聚集數增(zeng)大。

少(shao)量極性(xing)(xing)有機(ji)物的(de)(de)加(jia)入(ru)，常使表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)劑(ji)(ji)溶液(ye)的(de)(de)CITIC發生顯(xian)著變化，但(dan)情況比較(jiao)復(fu)雜(za)。脂(zhi)肪(fang)醇無論是對陽(yang)離子表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)劑(ji)(ji)還是對陰離子表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)劑(ji)(ji)的(de)(de)溶液(ye)，均能顯(xian)著降低(di)其臨界膠(jiao)團(tuan)濃度、表(biao)(biao)面(mian)(mian)(mian)張(zhang)(zhang)力(li)，提高起泡性(xing)(xing)、乳化性(xing)(xing)等表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)，并(bing)且這(zhe)種作用(yong)隨(sui)脂(zhi)肪(fang)醇的(de)(de)濃度增加(jia)和(he)醇的(de)(de)烴鏈的(de)(de)加(jia)長而變得越發顯(xian)著。這(zhe)是因為醇分(fen)(fen)子CnH2n+1OH與(yu)表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)劑(ji)(ji)分(fen)(fen)子CnH2n+1S04Na之間(jian)有較(jiao)強(qiang)烈的(de)(de)相互作用(yong)，如烴基的(de)(de)疏水作用(yong)，極性(xing)(xing)頭(tou)的(de)(de)氫鍵結(jie)合，而使脂(zhi)肪(fang)醇分(fen)(fen)子和(he)表(biao)(biao)面(mian)(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)劑(ji)(ji)離子在表(biao)(biao)面(mian)(mian)(mian)上定(ding)向排(pai)列很(hen)緊密，從而大大改變水的(de)(de)表(biao)(biao)面(mian)(mian)(mian)性(xing)(xing)質，即使接近非極性(xing)(xing)表(biao)(biao)面(mian)(mian)(mian)，也表(biao)(biao)現出很(hen)低(di)的(de)(de)表(biao)(biao)面(mian)(mian)(mian)張(zhang)(zhang)力(li)。另外(wai)加(jia)入(ru)脂(zhi)肪(fang)醇后，溶液(ye)的(de)(de)黏度加(jia)大。

清(qing)洗(xi)(xi)(xi)(xi)液(ye)中使用表(biao)面(mian)活(huo)性(xing)(xing)劑作(zuo)(zuo)清(qing)洗(xi)(xi)(xi)(xi)劑，降低清(qing)洗(xi)(xi)(xi)(xi)液(ye)及(ji)污(wu)(wu)(wu)物(wu)(wu)間(jian)界面(mian)張力(li)，清(qing)洗(xi)(xi)(xi)(xi)液(ye)首先(xian)可潤(run)濕污(wu)(wu)(wu)物(wu)(wu)表(biao)面(mian)，使污(wu)(wu)(wu)物(wu)(wu)膨潤(run)，然后(hou)滲透到污(wu)(wu)(wu)物(wu)(wu)之(zhi)間(jian)，使污(wu)(wu)(wu)物(wu)(wu)分散。污(wu)(wu)(wu)物(wu)(wu)如屬(shu)油(you)(you)類，則油(you)(you)脂先(xian)形成球狀聚(ju)集在金(jin)(jin)屬(shu)表(biao)面(mian)，表(biao)面(mian)活(huo)性(xing)(xing)劑擠入，使污(wu)(wu)(wu)物(wu)(wu)自金(jin)(jin)屬(shu)表(biao)面(mian)脫(tuo)離(li)，移至(zhi)清(qing)洗(xi)(xi)(xi)(xi)液(ye)中。本來不溶解(jie)(jie)的油(you)(you)污(wu)(wu)(wu)粒子，在表(biao)面(mian)活(huo)性(xing)(xing)劑膠(jiao)束中包圍而“增(zeng)溶”于清(qing)洗(xi)(xi)(xi)(xi)液(ye)中，不會再吸附到金(jin)(jin)屬(shu)表(biao)面(mian)上。在洗(xi)(xi)(xi)(xi)滌時，如有(you)機械力(li)作(zuo)(zuo)用，就(jiu)有(you)助于污(wu)(wu)(wu)物(wu)(wu)脫(tuo)離(li)金(jin)(jin)屬(shu)表(biao)面(mian)，提高(gao)清(qing)洗(xi)(xi)(xi)(xi)效果。由表(biao)面(mian)活(huo)性(xing)(xing)劑制(zhi)備的乳(ru)狀液(ye)除了(le)具有(you)上述清(qing)洗(xi)(xi)(xi)(xi)劑的清(qing)洗(xi)(xi)(xi)(xi)作(zuo)(zuo)用外，還根據溶劑相似(si)溶解(jie)(jie)原理(li)，內(nei)相油(you)(you)相的存在將(jiang)使其對(dui)油(you)(you)污(wu)(wu)(wu)的溶解(jie)(jie)清(qing)洗(xi)(xi)(xi)(xi)作(zuo)(zuo)用大(da)大(da)增(zeng)強(qiang)。理(li)想的清(qing)洗(xi)(xi)(xi)(xi)乳(ru)狀液(ye)，一般(ban)具有(you)以下四個特性(xing)(xing)：

(1)乳狀液穩定，油相對(dui)油污溶解能(neng)力(li)強;

(2)油相粘度低，最終易于水洗(xi)干凈(jing);

(3)油相最好無(wu)揮發性、無(wu)毒、清(qing)洗(xi)過程不會產生污染;

(4)容易破乳回(hui)收，再(zai)生利(li)用。