常用的表面活性劑主(zhu)要是偶聯劑、高級脂肪酸(suan)及(ji)其鹽、不飽和有(you)機(ji)酸(suan)和有(you)機(ji)硅(gui)等。偶聯劑是常(chang)用的礦物表面(mian)活性(xing)劑。

晶(jing)體結(jie)塊是指晶(jing)體從松散狀態(tai)轉變為(wei)塊團的現象(xiang)。結(jie)塊使晶(jing)體顆粒流(liu)動(dong)性變差,直(zhi)接(jie)影響產品的使用性能。在(zai)產品結(jie)晶(jing)過程中(zhong)向溶液中(zhong)加入(ru)微量表(biao)面活性劑,可有效防止產品的結(jie)塊現象(xiang)。

其作(zuo)用(yong)機理為(wei):①表面(mian)活性劑進(jin)入結晶(jing)(jing)(jing)(jing)(jing)(jing)系統中,在晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)表面(mian)形(xing)(xing)成(cheng)(cheng)包裹膜(mo),使(shi)晶(jing)(jing)(jing)(jing)(jing)(jing)粒間(jian)產(chan)生機械隔離效果;②吸(xi)(xi)附(fu)于晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)表面(mian)形(xing)(xing)成(cheng)(cheng)疏水層,阻(zu)止(zhi)了晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)與大氣的水分交換(huan);③降(jiang)低(di)溶(rong)液的表面(mian)張力(li),改變(bian)(bian)固(gu)液間(jian)的界(jie)面(mian)接觸角,使(shi)晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)對溶(rong)液的毛吸(xi)(xi)管吸(xi)(xi)附(fu)力(li)降(jiang)低(di);④參與晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)生產(chan)過程,改變(bian)(bian)各晶(jing)(jing)(jing)(jing)(jing)(jing)面(mian)的相對生長速率,改善(shan)顆(ke)粒結晶(jing)(jing)(jing)(jing)(jing)(jing)習性,降(jiang)低(di)晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)界(jie)面(mian)能(neng),從而改變(bian)(bian)晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)形(xing)(xing)態(tai)。例如烷(wan)基(ji)磺(huang)酸(suan)鹽及其中間(jian)體(ti)(ti)(ti)(ti)(ti)烷(wan)基(ji)磺(huang)酰氯、烷(wan)基(ji)苯磺(huang)酸(suan)鹽、對甲苯磺(huang)酸(suan)鈉(na)(na)、脂肪酸(suan)鈉(na)(na)等可作(zuo)為(wei)晶(jing)(jing)(jing)(jing)(jing)(jing)體(ti)(ti)(ti)(ti)(ti)產(chan)品防結塊(kuai)劑。

生物(wu)(wu)(wu)(wu)表(biao)面(mian)活(huo)性(xing)(xing)劑促進(jin)有(you)(you)機污(wu)染(ran)物(wu)(wu)(wu)(wu)降(jiang)(jiang)(jiang)解(jie)的(de)(de)作用機理、其(qi)與降(jiang)(jiang)(jiang)解(jie)菌株(zhu)及底物(wu)(wu)(wu)(wu)的(de)(de)相互作用關系都還不甚清楚。雖然生物(wu)(wu)(wu)(wu)表(biao)面(mian)活(huo)性(xing)(xing)劑促進(jin)了(le)微生物(wu)(wu)(wu)(wu)降(jiang)(jiang)(jiang)解(jie)，但它們也(ye)(ye)有(you)(you)一(yi)些(xie)抑制因素，如(ru)有(you)(you)些(xie)表(biao)面(mian)活(huo)性(xing)(xing)劑濃度(du)達到CMC以上時就對微生物(wu)(wu)(wu)(wu)有(you)(you)毒(du)性(xing)(xing)，有(you)(you)些(xie)生物(wu)(wu)(wu)(wu)表(biao)面(mian)活(huo)性(xing)(xing)劑的(de)(de)膠粒能干擾細胞過程(cheng)。生物(wu)(wu)(wu)(wu)表(biao)面(mian)活(huo)性(xing)(xing)劑也(ye)(ye)能作為一(yi)種優先碳(tan)源，與有(you)(you)機污(wu)染(ran)物(wu)(wu)(wu)(wu)的(de)(de)降(jiang)(jiang)(jiang)解(jie)形成(cheng)競爭，從(cong)而導(dao)致(zhi)污(wu)染(ran)物(wu)(wu)(wu)(wu)降(jiang)(jiang)(jiang)解(jie)率下降(jiang)(jiang)(jiang)。此外(wai)表(biao)面(mian)活(huo)性(xing)(xing)劑還可能造成(cheng)微生物(wu)(wu)(wu)(wu)數(shu)量的(de)(de)分散而導(dao)致(zhi)不同的(de)(de)結果(guo)。這些(xie)作用機理都需要深入探究(jiu)。?

表(biao)(biao)(biao)面(mian)(mian)化(hua)學(xue)改性(xing)(xing)(xing)是通過表(biao)(biao)(biao)面(mian)(mian)活性(xing)(xing)(xing)劑與(yu)無機粉(fen)體顆粒(li)表(biao)(biao)(biao)面(mian)(mian)進行(xing)化(hua)學(xue)反應或化(hua)學(xue)吸附的方式對(dui)顆粒(li)表(biao)(biao)(biao)面(mian)(mian)進行(xing)局部包覆使顆粒(li)表(biao)(biao)(biao)面(mian)(mian)有機化(hua),以(yi)完成表(biao)(biao)(biao)面(mian)(mian)改性(xing)(xing)(xing)。 

劉茜等用(yong)表(biao)(biao)面(mian)活性(xing)(xing)劑聚乙二醇處理SiC超細顆(ke)(ke)粒(li)(li),聚乙二醇分子鏈(lian)被修飾(shi)在SiC顆(ke)(ke)粒(li)(li)表(biao)(biao)面(mian),起(qi)空(kong)間位阻屏障作用(yong),防止(zhi)固體SiC顆(ke)(ke)粒(li)(li)再(zai)度團(tuan)聚。形狀不規則或(huo)已(yi)發生團(tuan)聚的SiC粉末經表(biao)(biao)面(mian)活性(xing)(xing)劑處理后,表(biao)(biao)面(mian)活性(xing)(xing)劑長分子鏈(lian)吸附在顆(ke)(ke)粒(li)(li)表(biao)(biao)面(mian)缺(que)陷及(ji)懸空(kong)鍵上,加(jia)速大顆(ke)(ke)粒(li)(li)或(huo)團(tuan)聚顆(ke)(ke)粒(li)(li)的解(jie)體,有益改善SiC顆(ke)(ke)粒(li)(li)的分散性(xing)(xing)。