電解質和表面活性劑的復配作用

    總的來說，存在于(yu)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)溶液(ye)中的電(dian)解質(一般為(wei)(wei)無(wu)機(ji)鹽(yan))，往(wang)往(wang)使(shi)溶液(ye)的表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)提高。但對于(yu)離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)和非離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)情況有些不(bu)同。對于(yu)離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)，在溶液(ye)中加入(ru)與表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)有相(xiang)同離(li)(li)子(zi)(zi)(zi)的無(wu)機(ji)鹽(yan)時(如RS04Na中加入(ru)NaCl)，溶液(ye)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)提高，cmc下降。例如，對于(yu)cmc=1 X 10 -4mol／L的離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)當反離(li)(li)子(zi)(zi)(zi)(反離(li)(li)子(zi)(zi)(zi)即與離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)帶(dai)有相(xiang)反電(dian)荷(he)的離(li)(li)子(zi)(zi)(zi))總濃度為(wei)(wei)0．1mol／L時，cmc則降低到1．6×10-6mol／L，前后相(xiang)差100倍。另(ling)外，電(dian)解質還能顯著(zhu)促進離(li)(li)子(zi)(zi)(zi)型(xing)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)劑(ji)的締合(he)，使(shi)其膠團聚集數增大。

少(shao)量極(ji)性有機物的(de)(de)加入，常使表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性劑溶(rong)(rong)液(ye)的(de)(de)CITIC發生顯著變(bian)化，但情況比較復雜。脂肪(fang)醇(chun)(chun)(chun)無論是對陽離子(zi)(zi)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性劑還是對陰離子(zi)(zi)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性劑的(de)(de)溶(rong)(rong)液(ye)，均(jun)能顯著降低(di)其(qi)臨界膠團濃(nong)(nong)度、表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)張力，提(ti)高起泡(pao)性、乳化性等表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性，并(bing)且(qie)這(zhe)種作用隨脂肪(fang)醇(chun)(chun)(chun)的(de)(de)濃(nong)(nong)度增加和(he)醇(chun)(chun)(chun)的(de)(de)烴鏈的(de)(de)加長而變(bian)得(de)越(yue)發顯著。這(zhe)是因為醇(chun)(chun)(chun)分(fen)子(zi)(zi)CnH2n+1OH與表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性劑分(fen)子(zi)(zi)CnH2n+1S04Na之間(jian)有較強烈的(de)(de)相互作用，如烴基的(de)(de)疏水作用，極(ji)性頭(tou)的(de)(de)氫鍵結(jie)合，而使脂肪(fang)醇(chun)(chun)(chun)分(fen)子(zi)(zi)和(he)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性劑離子(zi)(zi)在(zai)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)上定向排列很(hen)緊密(mi)，從(cong)而大(da)大(da)改(gai)變(bian)水的(de)(de)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)性質，即使接近非極(ji)性表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)，也表(biao)(biao)(biao)現出很(hen)低(di)的(de)(de)表(biao)(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)張力。另外加入脂肪(fang)醇(chun)(chun)(chun)后，溶(rong)(rong)液(ye)的(de)(de)黏度加大(da)。

清(qing)(qing)洗(xi)液(ye)中(zhong)(zhong)使(shi)用(yong)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)(xing)(xing)劑(ji)作(zuo)(zuo)清(qing)(qing)洗(xi)劑(ji)，降(jiang)低清(qing)(qing)洗(xi)液(ye)及(ji)污(wu)物(wu)間界面(mian)(mian)張力(li)，清(qing)(qing)洗(xi)液(ye)首先可潤濕污(wu)物(wu)表(biao)(biao)(biao)面(mian)(mian)，使(shi)污(wu)物(wu)膨潤，然后滲透到(dao)污(wu)物(wu)之間，使(shi)污(wu)物(wu)分散(san)。污(wu)物(wu)如(ru)屬(shu)(shu)(shu)油(you)(you)類，則油(you)(you)脂先形(xing)成(cheng)球狀聚集在(zai)(zai)(zai)金屬(shu)(shu)(shu)表(biao)(biao)(biao)面(mian)(mian)，表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)(xing)(xing)劑(ji)擠入，使(shi)污(wu)物(wu)自金屬(shu)(shu)(shu)表(biao)(biao)(biao)面(mian)(mian)脫離，移至清(qing)(qing)洗(xi)液(ye)中(zhong)(zhong)。本來不溶(rong)(rong)解的(de)油(you)(you)污(wu)粒(li)子(zi)，在(zai)(zai)(zai)表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)(xing)(xing)劑(ji)膠束中(zhong)(zhong)包(bao)圍而“增溶(rong)(rong)”于清(qing)(qing)洗(xi)液(ye)中(zhong)(zhong)，不會再吸附到(dao)金屬(shu)(shu)(shu)表(biao)(biao)(biao)面(mian)(mian)上(shang)。在(zai)(zai)(zai)洗(xi)滌時，如(ru)有機械(xie)力(li)作(zuo)(zuo)用(yong)，就有助(zhu)于污(wu)物(wu)脫離金屬(shu)(shu)(shu)表(biao)(biao)(biao)面(mian)(mian)，提(ti)高(gao)清(qing)(qing)洗(xi)效果。由表(biao)(biao)(biao)面(mian)(mian)活(huo)性(xing)(xing)(xing)劑(ji)制(zhi)備的(de)乳狀液(ye)除了(le)具(ju)有上(shang)述清(qing)(qing)洗(xi)劑(ji)的(de)清(qing)(qing)洗(xi)作(zuo)(zuo)用(yong)外，還根據溶(rong)(rong)劑(ji)相(xiang)似(si)溶(rong)(rong)解原(yuan)理，內相(xiang)油(you)(you)相(xiang)的(de)存在(zai)(zai)(zai)將使(shi)其(qi)對油(you)(you)污(wu)的(de)溶(rong)(rong)解清(qing)(qing)洗(xi)作(zuo)(zuo)用(yong)大大增強。理想的(de)清(qing)(qing)洗(xi)乳狀液(ye)，一般具(ju)有以(yi)下四個特性(xing)(xing)(xing)：

(1)乳狀液穩定，油相(xiang)對油污溶解能力強;

(2)油相粘(zhan)度(du)低(di)，最終易于水(shui)洗干凈;

(3)油相最好無揮(hui)發性、無毒、清洗過程不會產(chan)生污(wu)染;

(4)容(rong)易破乳回(hui)收，再(zai)生利用。