工(gong)業廢(fei)水回(hui)收(shou)有(you)機物裝置利用半透(tou)膜或選(xuan)擇透(tou)過(guo)性離(li)子交換膜使溶(rong)液中的溶(rong)質由高濃度一(yi)側(ce)通過(guo)膜向低濃度一(yi)側(ce)遷(qian)移的過(guo)程(cheng)。這種過(guo)程(cheng)是以濃度差(cha)為動力(li)，也稱之為濃差(cha)滲析或自(zi)然滲析。在環境工程(cheng)方面(mian)主要用于有機(ji)(ji)和無機(ji)(ji)電解質的分(fen)離(li)、純化和酸、堿廢液的處理(li)和回收。

高(gao)濃度(du)溶(rong)液中的(de)溶(rong)質(zhi)以濃度(du)差為(wei)推動力透過(guo)隔(ge)膜(mo)向(xiang)低濃度(du)溶(rong)液中遷移(yi)。

采用(yong)離(li)子交換膜(mo)：陰膜(mo)、陽膜(mo)。

主(zhu)要用(yong)于：回收(shou)酸、堿(jian)，但不能將它們濃縮。

優勢：消耗能(neng)量極少、運行成本低(di)、膜壽命長(chang)。

工業廢水回收有(you)機(ji)物(wu)裝置利用半(ban)透膜或(huo)選擇透過性離子(zi)交(jiao)換膜使溶液(ye)中的溶質(zhi)由高濃(nong)度(du)一側通過膜向(xiang)低濃(nong)度(du)一側遷移(yi)的過程(cheng)。這種過程(cheng)是以濃(nong)度(du)差(cha)為(wei)動(dong)力，所(suo)以也稱(cheng)為(wei)濃(nong)差(cha)滲(shen)析或(huo)自然滲(shen)析。它(ta)主要用于(yu)有機和無機電解質(zhi)的分離和純(chun)化。在環境(jing)工程(cheng)方面(mian)目前主要用于(yu)酸、堿廢液(ye)的處理和回收。

19世紀50年(nian)(nian)代初(chu)，英國化(hua)學家T.格(ge)雷厄姆開始系統地研究(jiu)溶液(ye)(ye)的擴(kuo)(kuo)散作(zuo)用(yong)(yong)(yong)，隨后又研究(jiu)了不同(tong)(tong)溶質通(tong)(tong)過(guo)半透(tou)(tou)膜(mo)(mo)(mo)(mo)(mo)（羊皮(pi)紙或棉膠(jiao)(jiao)等制成(cheng)的薄膜(mo)(mo)(mo)(mo)(mo)）的特性，發現一(yi)些溶質的分(fen)(fen)(fen)子(zi)(zi)(zi)或離(li)(li)(li)子(zi)(zi)(zi)能(neng)通(tong)(tong)過(guo)半透(tou)(tou)膜(mo)(mo)(mo)(mo)(mo)的細孔，而(er)(er)較大的膠(jiao)(jiao)體粒子(zi)(zi)(zi)不能(neng)通(tong)(tong)過(guo)的現象。格(ge)雷厄姆稱此現象為(wei)(wei)(wei)滲(shen)(shen)析(xi)(xi)。根(gen)(gen)據(ju)這(zhe)個原理(li)制成(cheng)的設備稱為(wei)(wei)(wei)滲(shen)(shen)析(xi)(xi)器(qi)，常用(yong)(yong)(yong)于膠(jiao)(jiao)體溶液(ye)(ye)的濃縮以及(ji)核酸(suan)、蛋白質等高分(fen)(fen)(fen)子(zi)(zi)(zi)化(hua)合物的提純(chun)。20世紀50年(nian)(nian)代出(chu)現了以離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)作(zuo)為(wei)(wei)(wei)隔膜(mo)(mo)(mo)(mo)(mo)的擴(kuo)(kuo)散滲(shen)(shen)析(xi)(xi)器(qi)。離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)擴(kuo)(kuo)散滲(shen)(shen)析(xi)(xi)器(qi)由離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)、隔板(ban)(ban)(ban)和夾緊裝置(zhi)組成(cheng)。離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)是滲(shen)(shen)析(xi)(xi)器(qi)的關鍵部件(jian)，可(ke)根(gen)(gen)據(ju)不同(tong)(tong)用(yong)(yong)(yong)途(tu)選(xuan)用(yong)(yong)(yong)不同(tong)(tong)的型(xing)號。隔板(ban)(ban)(ban)是膜(mo)(mo)(mo)(mo)(mo)的支撐體和水流通(tong)(tong)道，隔板(ban)(ban)(ban)材料(liao)有聚氯乙烯、聚乙烯、聚丙烯塑料(liao)和橡膠(jiao)(jiao)等。夾緊裝置(zhi)常采(cai)用(yong)(yong)(yong)鐵板(ban)(ban)(ban)、螺栓(shuan)或液(ye)(ye)壓部件(jian)，把膜(mo)(mo)(mo)(mo)(mo)和隔板(ban)(ban)(ban)組成(cheng)一(yi)個整體。采(cai)用(yong)(yong)(yong)陽(yang)離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)，其固定基團(tuan)帶負電荷，只允許(xu)陽(yang)離(li)(li)(li)子(zi)(zi)(zi)透(tou)(tou)過(guo)，而(er)(er)阻(zu)擋陰離(li)(li)(li)子(zi)(zi)(zi)；采(cai)用(yong)(yong)(yong)陰離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)則相反。雖然(ran)陽(yang)離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)有阻(zu)止陰離(li)(li)(li)子(zi)(zi)(zi)通(tong)(tong)過(guo)的選(xuan)擇性，但是氫氧離(li)(li)(li)子(zi)(zi)(zi)(OH-)卻(que)能(neng)通(tong)(tong)過(guo);而(er)(er)氫離(li)(li)(li)子(zi)(zi)(zi)(H )同(tong)(tong)樣也能(neng)通(tong)(tong)過(guo)陰離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)。酸(suan)根(gen)(gen)離(li)(li)(li)子(zi)(zi)(zi)和H 分(fen)(fen)(fen)別(bie)通(tong)(tong)過(guo)陰離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)后結(jie)(jie)合為(wei)(wei)(wei)酸(suan);金(jin)屬離(li)(li)(li)子(zi)(zi)(zi)和OH-分(fen)(fen)(fen)別(bie)通(tong)(tong)過(guo)陽(yang)離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)后結(jie)(jie)合為(wei)(wei)(wei)堿。利用(yong)(yong)(yong)離(li)(li)(li)子(zi)(zi)(zi)交(jiao)(jiao)(jiao)(jiao)(jiao)換(huan)(huan)(huan)(huan)(huan)膜(mo)(mo)(mo)(mo)(mo)的這(zhe)種(zhong)選(xuan)擇透(tou)(tou)過(guo)作(zuo)用(yong)(yong)(yong)，可(ke)以分(fen)(fen)(fen)離(li)(li)(li)有機(ji)(ji)膠(jiao)(jiao)質、無機(ji)(ji)電解質，回收酸(suan)和堿。