表面活性劑通常(chang)由親脂(zhi)、非(fei)極(ji)性(xing)(xing)(xing)(xing)的(de)碳(tan)氫(qing)(qing)鏈（憎水(shui)基(ji)(ji)）和(he)親水(shui)、極(ji)性(xing)(xing)(xing)(xing)的(de)基(ji)(ji)團(tuan)(tuan)（親水(shui)基(ji)(ji)）共同(tong)(tong)構成。根據親水(shui)基(ji)(ji)團(tuan)(tuan)的(de)帶電(dian)狀況，表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑可分為非(fei)離(li)子(zi)型、陰離(li)子(zi)型、陽離(li)子(zi)型和(he)兩(liang)性(xing)(xing)(xing)(xing)型。由于(yu)(yu)表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑種類的(de)多樣(yang)性(xing)(xing)(xing)(xing)和(he)土(tu)壤結構的(de)復雜性(xing)(xing)(xing)(xing)，表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑在(zai)土(tu)壤上的(de)吸(xi)附(fu)機理是相當復雜的(de)。主(zhu)要(yao)通過(guo)以下方(fang)式進行(xing)：1）離(li)子(zi)交換(huan)吸(xi)附(fu)，吸(xi)附(fu)于(yu)(yu)土(tu)壤表(biao)(biao)(biao)面(mian)(mian)的(de)反(fan)離(li)子(zi)被(bei)同(tong)(tong)電(dian)性(xing)(xing)(xing)(xing)的(de)表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑離(li)子(zi)所(suo)取(qu)代；2）離(li)子(zi)對吸(xi)附(fu)，表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑離(li)子(zi)吸(xi)附(fu)于(yu)(yu)具有相反(fan)電(dian)荷的(de)、未被(bei)反(fan)離(li)子(zi)所(suo)占據的(de)位置上；3）氫(qing)(qing)鍵(jian)(jian)吸(xi)附(fu)，表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑與土(tu)壤表(biao)(biao)(biao)面(mian)(mian)極(ji)性(xing)(xing)(xing)(xing)基(ji)(ji)團(tuan)(tuan)形成氫(qing)(qing)鍵(jian)(jian)而(er)吸(xi)附(fu)；4）憎水(shui)吸(xi)附(fu)，表(biao)(biao)(biao)面(mian)(mian)活(huo)(huo)(huo)性(xing)(xing)(xing)(xing)劑通過(guo)憎水(shui)基(ji)(ji)吸(xi)附(fu)在(zai)土(tu)壤表(biao)(biao)(biao)面(mian)(mian)上，而(er)親水(shui)基(ji)(ji)朝(chao)外；5）范(fan)德華力吸(xi)附(fu)，此(ci)種吸(xi)附(fu)在(zai)任何場合均存在(zai)。

在較低的表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)濃度(du)下，離(li)子(zi)型表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)主要(yao)通(tong)過離(li)子(zi)對或離(li)子(zi)交換作(zuo)(zuo)用吸附(fu)在土(tu)壤表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)上(shang)，非離(li)子(zi)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)則主要(yao)通(tong)過與土(tu)壤粒子(zi)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)基(ji)團形(xing)成氫鍵而(er)吸附(fu)，此時(shi)吸附(fu)等溫線(xian)(xian)通(tong)常為直線(xian)(xian)；隨著(zhu)表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)濃度(du)的增加，表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)可通(tong)過憎水基(ji)團的相互作(zuo)(zuo)用在土(tu)壤表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)形(xing)成雙層吸附(fu)，此時(shi)吸附(fu)量(liang)呈(cheng)指數增長(chang)。之后，表(biao)(biao)面(mian)(mian)(mian)(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)在土(tu)壤上(shang)的吸附(fu)基(ji)本飽和。

影響表(biao)面活性劑在土(tu)壤上的吸附因素(su)有很多，包(bao)括表(biao)面活性劑的結構、外(wai)部環境條件以及土(tu)壤的理化性質(zhi)等。

研(yan)究表(biao)明，隨(sui)著(zhu)表(biao)面(mian)活性(xing)劑(ji)碳(tan)鏈(lian)長(chang)(chang)度的(de)(de)增(zeng)(zeng)(zeng)(zeng)加(jia)，其在(zai)(zai)土(tu)壤(rang)(rang)(rang)膠體上(shang)的(de)(de)吸附(fu)也增(zeng)(zeng)(zeng)(zeng)加(jia)，這可(ke)能是(shi)由于較長(chang)(chang)的(de)(de)碳(tan)鏈(lian)降(jiang)低了表(biao)面(mian)活性(xing)劑(ji)臨界(jie)膠束濃度（CMC）。對(dui)于聚氧乙(yi)(yi)烯(xi)類非(fei)離子(zi)(zi)表(biao)面(mian)活性(xing)劑(ji)，隨(sui)著(zhu)聚氧乙(yi)(yi)烯(xi)鏈(lian)長(chang)(chang)的(de)(de)增(zeng)(zeng)(zeng)(zeng)加(jia)，其在(zai)(zai)土(tu)壤(rang)(rang)(rang)上(shang)的(de)(de)吸附(fu)減少，這可(ke)能和聚氧乙(yi)(yi)烯(xi)鏈(lian)增(zeng)(zeng)(zeng)(zeng)加(jia)使得非(fei)離子(zi)(zi)表(biao)面(mian)活性(xing)劑(ji)在(zai)(zai)溶液中溶解(jie)度增(zeng)(zeng)(zeng)(zeng)加(jia)有關。隨(sui)著(zhu)土(tu)壤(rang)(rang)(rang)溶液pH的(de)(de)降(jiang)低，由于土(tu)壤(rang)(rang)(rang)中有機(ji)質、鐵錳氧化物或高嶺土(tu)等的(de)(de)存在(zai)(zai)，土(tu)壤(rang)(rang)(rang)表(biao)面(mian)正電(dian)荷(he)和氫氧基團將增(zeng)(zeng)(zeng)(zeng)加(jia)，因而非(fei)離子(zi)(zi)及(ji)陰離子(zi)(zi)表(biao)面(mian)活性(xing)劑(ji)在(zai)(zai)土(tu)壤(rang)(rang)(rang)中的(de)(de)吸附(fu)增(zeng)(zeng)(zeng)(zeng)加(jia)。

增加溫(wen)度(du)可(ke)增加離(li)子(zi)(zi)型(xing)表面活(huo)性劑的溶(rong)(rong)解(jie)度(du)，因而(er)其從溶(rong)(rong)液中逃逸的傾向性減少，導致在土壤顆(ke)粒(li)表面的吸(xi)附(fu)(fu)量(liang)降(jiang)低。相(xiang)反(fan)，由于增加溫(wen)度(du)可(ke)降(jiang)低非離(li)子(zi)(zi)表面活(huo)性劑的溶(rong)(rong)解(jie)度(du)，因而(er)在土壤顆(ke)粒(li)表面的吸(xi)附(fu)(fu)量(liang)趨于增加。

由于陽(yang)(yang)離(li)(li)(li)子(zi)表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)主要通過離(li)(li)(li)子(zi)交(jiao)換(huan)吸(xi)(xi)附在(zai)土(tu)壤(rang)(rang)界面(mian)(mian)(mian)上，因而陽(yang)(yang)離(li)(li)(li)子(zi)交(jiao)換(huan)容量高的(de)土(tu)壤(rang)(rang)對陽(yang)(yang)離(li)(li)(li)子(zi)表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)的(de)吸(xi)(xi)附較多。土(tu)壤(rang)(rang)中的(de)無(wu)(wu)機(ji)(ji)鹽(yan)(yan)對表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)在(zai)土(tu)壤(rang)(rang)中的(de)吸(xi)(xi)附有較重要的(de)影響(xiang)。Liu等研究表(biao)(biao)明增(zeng)加土(tu)壤(rang)(rang)中無(wu)(wu)機(ji)(ji)鹽(yan)(yan)的(de)含量，可以增(zeng)加表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)的(de)吸(xi)(xi)附，這(zhe)可能是因為一(yi)方(fang)(fang)面(mian)(mian)(mian)較高濃度的(de)無(wu)(wu)機(ji)(ji)鹽(yan)(yan)壓(ya)縮土(tu)壤(rang)(rang)粒子(zi)表(biao)(biao)面(mian)(mian)(mian)的(de)擴(kuo)散雙(shuang)電層，降低(di)了土(tu)壤(rang)(rang)顆粒表(biao)(biao)面(mian)(mian)(mian)電荷，使(shi)得表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)較容易(yi)接近并吸(xi)(xi)附在(zai)土(tu)壤(rang)(rang)表(biao)(biao)面(mian)(mian)(mian)，另一(yi)方(fang)(fang)面(mian)(mian)(mian)，無(wu)(wu)機(ji)(ji)鹽(yan)(yan)降低(di)表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)CMC也(ye)可能導(dao)致(zhi)吸(xi)(xi)附量增(zeng)加。由于二價陽(yang)(yang)離(li)(li)(li)子(zi)可與陰離(li)(li)(li)子(zi)表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)形成沉淀，因此將直(zhi)接導(dao)致(zhi)陰離(li)(li)(li)子(zi)表(biao)(biao)面(mian)(mian)(mian)活(huo)性(xing)(xing)劑(ji)(ji)在(zai)土(tu)壤(rang)(rang)上吸(xi)(xi)附的(de)增(zeng)加。