制(zhi)約電(dian)(dian)(dian)(dian)(dian)凝(ning)聚(ju)廣泛應用的(de)(de)主要原因是其能(neng)耗較高(gao)。故對降低其能(neng)耗的(de)(de)研究一直在(zai)持續進(jin)行。實(shi)驗表明,槽電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)對處理(li)效(xiao)果影(ying)響最大,過(guo)(guo)低處理(li)效(xiao)果不(bu)好,過(guo)(guo)高(gao)則增加能(neng)耗。通(tong)過(guo)(guo)理(li)論分析與實(shi)驗,陳(chen)雪明提出(chu)了計算(suan)分解電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya)的(de)(de)半經驗公式: 鐵板作(zuo)電(dian)(dian)(dian)(dian)(dian)極(ji)材(cai)料:U=(d/k+0.04)i+0.4 鋁板作(zuo)電(dian)(dian)(dian)(dian)(dian)極(ji)材(cai)料:U= (d/k+0.04)i+1.0 式中(zhong),U為單元(yuan)分解電(dian)(dian)(dian)(dian)(dian)壓(ya)(ya),V;d為電(dian)(dian)(dian)(dian)(dian)極(ji)間凈(jing)距離,m; k為被處理(li)水的(de)(de)電(dian)(dian)(dian)(dian)(dian)導(dao)率,S/m;i為電(dian)(dian)(dian)(dian)(dian)流(liu)密度,A/m2。由(you)電(dian)(dian)(dian)(dian)(dian)凝(ning)聚(ju)器能(neng)耗公式可得(de)知:i、d及電(dian)(dian)(dian)(dian)(dian)流(liu)泄漏率越小,能(neng)耗E也越小。但k的(de)(de)情況較復雜,當(dang)k 較小時(shi),E隨k的(de)(de)增大而下降,當(dang)k超過(guo)(guo)了某一限值時(shi),隨著k的(de)(de)增大,E也增大。

為了(le)降(jiang)低電(dian)凝(ning)聚(ju)法(fa)的能耗(hao),提(ti)出了(le)不少建議及(ji)措施,概括如下:

 (1)電(dian)(dian)(dian)源技術的改進。采用(yong)脈沖電(dian)(dian)(dian)源。由于施加脈沖信號,電(dian)(dian)(dian)極(ji)上的反應時斷時續,有利(li)于擴(kuo)散, 降(jiang)低濃差極(ji)化(hua),從(cong)而(er)降(jiang)低能耗。而(er)當電(dian)(dian)(dian)解槽施加交流(liu)電(dian)(dian)(dian)信號時,由于兩極(ji)均(jun)可(ke)溶,可(ke)從(cong)兩極(ji)產生陽離子,更(geng)有利(li)于金屬離子與膠體間(jian)的作用(yong)。同(tong)時由于兩極(ji)極(ji)性經常變化(hua),對防止電(dian)(dian)(dian)極(ji)鈍化(hua)起到了積極(ji)的作用(yong)。

 (2)新型電(dian)(dian)(dian)極(ji)(ji)的應用(yong)。三維(wei)電(dian)(dian)(dian)極(ji)(ji)的面(mian)體比極(ji)(ji)大增加,并且粒子間距小,物(wu)質傳質效果極(ji)(ji)大改(gai)善,因而具有較高的電(dian)(dian)(dian)流效率(lv)和單位(wei)時空效率(lv)。利用(yong)三維(wei)電(dian)(dian)(dian)極(ji)(ji)的原理,并巧妙(miao)地配(pei)以(yi)催化(hua)氧(yang)化(hua)技(ji)術,在最佳實驗(yan)條件下(xia),對高色度印(yin)染(ran)廢水(shui)處理20 min后,色度由(you)12 500倍降到(dao)62.5倍,CODCr由(you)794.6 mg/L降到(dao) 137.0 mg/L,脫色率(lv)達到(dao)99.5%,CODCr去除率(lv)為82. 8%。活性炭纖(xian)維(wei)-鐵復合電(dian)(dian)(dian)極(ji)(ji)用(yong)于處理上海某廠(chang)扎(zha)染(ran)殘液水(shui)樣(yang),在電(dian)(dian)(dian)壓(ya)15 V、pH 6.0、電(dian)(dian)(dian)解60 min條件下(xia),CODCr去除率(lv)在40%~80%。

 (3)電(dian)(dian)(dian)(dian)解(jie)(jie)槽(cao)(cao)的改進設計。將(jiang)流(liu)(liu)體的傳(chuan)質與(yu)電(dian)(dian)(dian)(dian)凝(ning)聚(ju)結合起(qi)來構成導流(liu)(liu)電(dian)(dian)(dian)(dian)凝(ning)聚(ju)法(fa)(fa)。電(dian)(dian)(dian)(dian)解(jie)(jie)槽(cao)(cao)的陰、陽(yang)極(ji)(ji)既起(qi)電(dian)(dian)(dian)(dian)極(ji)(ji)的作用,又起(qi)導流(liu)(liu)桶的作用,在較低攪拌速度(du)下可使槽(cao)(cao)內(nei)液(ye)體充(chong)分(fen)(fen)湍動(dong)。該法(fa)(fa)縮短(duan)電(dian)(dian)(dian)(dian)解(jie)(jie)脫(tuo)色(se)時間,減少極(ji)(ji)化作用,從(cong)而降低電(dian)(dian)(dian)(dian)耗。用導流(liu)(liu)電(dian)(dian)(dian)(dian)凝(ning)聚(ju)法(fa)(fa)處(chu)理(li)印染廢(fei)水,脫(tuo)色(se)率達97%時,電(dian)(dian)(dian)(dian)耗為(wei)0.425 kW·h/m3,其費(fei)用遠低于普通投(tou)藥混(hun)凝(ning)法(fa)(fa)和普通電(dian)(dian)(dian)(dian)解(jie)(jie)法(fa)(fa)。鐵陽(yang)極(ji)(ji)管(guan)式電(dian)(dian)(dian)(dian)凝(ning)聚(ju)器的陰極(ji)(ji)和陽(yang)極(ji)(ji)分(fen)(fen)別由內(nei)徑為(wei)36 mm的鋼管(guan)和16 mm的黑鐵管(guan)組成,管(guan)壁厚均為(wei)3 mm,陽(yang)極(ji)(ji)管(guan)置于陰極(ji)(ji)管(guan)之(zhi)內(nei)。其電(dian)(dian)(dian)(dian)極(ji)(ji)間距小 (約7 mm)、槽(cao)(cao)電(dian)(dian)(dian)(dian)壓低、電(dian)(dian)(dian)(dian)耗少、效率高。在電(dian)(dian)(dian)(dian)流(liu)(liu)密度(du)為(wei)20.6 A/m2時,電(dian)(dian)(dian)(dian)解(jie)(jie)8 min,含COD 500 mg/L的聚(ju)乙烯醇(chun)(PVA)廢(fei)水可達排放標準。在電(dian)(dian)(dian)(dian)流(liu)(liu)密度(du)為(wei) 56.1 A/m2時,電(dian)(dian)(dian)(dian)解(jie)(jie)35 min,可使COD去(qu)除率達 94%。

(4)電(dian)(dian)凝聚與(yu)其他工藝組合(he)。這種組合(he)種類多, 如某廠采(cai)用(yong)凝聚-砂濾法(fa)處理(li)制革染色廢(fei)水(shui)(shui)(shui),可使 CODCr從(cong)344~866 mg/L降(jiang)至(zhi)(zhi)44~135 mg/L,色度(du)從(cong) 20~100倍降(jiang)至(zhi)(zhi)2~25倍。該(gai)廠還采(cai)用(yong)交替(ti)改變電(dian)(dian)極(ji)極(ji)性和經常去除極(ji)板表面上(shang)的沉積物以(yi)減緩電(dian)(dian)極(ji)極(ji)化。將微絮凝過(guo)濾和電(dian)(dian)凝聚凈水(shui)(shui)(shui)技術(shu)兩者結合(he)起來處理(li)生活飲用(yong)水(shui)(shui)(shui),處理(li)低濁度(du)原水(shui)(shui)(shui)(不宜超過(guo)200 度(du),峰(feng)值(zhi)短(duan)期不超過(guo)300度(du))的工藝,技術(shu)上(shang)可行(xing),處理(li)效果(guo)好。綜上(shang)所述,電(dian)(dian)凝聚處理(li)廢(fei)水(shui)(shui)(shui)是一種有(you)發(fa)展前途的方(fang)法(fa)。 

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