結論與建議

5.1 結論

1. 鎂鹽混沉處理矽酸之效果優於PACl、Alum對矽酸之處理效果，尤其鎂鹽在高 pH值(pH 11)下形成Mg(OH)2固體物帶正電，對於水體中帶負電荷的矽酸具有 更好的去除效果。

2. 鎂鹽加藥劑量越大，對矽酸移除的效果越好，且可降低矽酸對薄膜發生結垢的 機會，但對於直接進流薄膜過濾所造成的通量衰減的程度較大。

3. 同時添加鎂鹽及 EPACl 混沉處理矽酸之去除效率較單獨鎂鹽處理之矽酸移除 率高，但前者對後續Cross-flow 薄膜通量衰減率較後者高；然而，在 Dead-end 式薄膜過濾過程中兩者卻有相反的結果。

4. 利用 ROSA 程式模擬出的結果，若前處理將矽酸移除越多，則可於 RO 操作 時得到越高的水回收率，可回推利用鎂鹽前處理時所需加入的劑量。

5. 對於矽酸移除提出一套處理程序，主要利用鎂鹽混凝前處理再配合後續的薄膜 過濾或混沉處理，其滲出液或上澄液即可導入 RO 操作系統中進行處理，不但 達到移除水中之矽酸成分，亦可達到水回收再利用之目標。

5.2 建議

1. 對於 PACl 及 Alum 對移除矽酸的部分可以再深入進行研究，並可對其進行探 討與鎂鹽之間的差異性作其比較。

2. 對鎂鹽及矽酸反應後所產生的沉澱物進行 XRD 晶相分析，並徹底了解鎂鹽與 矽酸之間的細部反應機制。

3. 探討矽酸吸附於薄膜表面的程度與薄膜本身的親疏水性是否有所關係，利用不

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