臭氧結合超重力旋轉填充床處理癒創木酚與木質素磺酸

Abstract

本研究利用臭氧結合超重力旋轉填充床(HGRPB)對木質素單體與工業木質素溶液進行氧化處理，進一步探討降低水體污染物的可行性。試驗溶液分別由不同分子量的癒創木酚(guaiacol)、磺甲基化木質素磺酸鈉(lignosulfonate)與鹼性木質素(alkali lignin)配製。利用不同的臭氧供應量與HGRPB轉速以及酸鹼條件處理溶液，探討化學需氧量(COD)、總有機碳(TOC)、單體濃度及重量分子量的變化，進而計算系統內平均每克臭氧的去污重量，評估系統去污的效果。濃度為0.1 g/L的guaiacol溶液實驗中，臭氧1 g/hr質傳進入系統中，HGRPB轉速為5400 rpm以及反應條件為pH 7為基準實驗參數，6 g/hr 臭氧質傳量在處理時間30 min後，比起基準參數多去除了13%的COD，12%的TOC與5%的濃度，顯示輸入系統的臭氧質量愈高，去污效果愈好。提高HGRPB轉速處理時間3 min後，7200 rpm比基準參數處理多下降4%的COD，6%的TOC與6%的濃度，隨著轉速的提高，可提昇反應初期的去污程度。鹼性條件下處理30 min，可多下降13%的COD，11%的TOC與5%的濃度，推測臭氧在鹼性條件下增加自由基影響水中有機物的氧化反應。分子量愈低的單體在同樣反應參數的去污程度大於另外兩者高分子化合物。高分子化合物溶液在不同的處理參數，重量平均分子量隨著COD與TOC的消長有所變化。基準參數下，0.1 g/L lignosulfonic 與alkali lignin溶液分別從分子量12030降至1147與60148降至7093。增加臭氧傳輸，HGRPB的轉速與鹼性環境反應皆提升重量分子量的下降。

This study combines the use of ozone system with High-Gravity Rotating Packed Bed (HGRPB) and conducts oxidation on solutions of lignin monomer and macromolecular compounds, in order to understand the viability for removal of water contaminants. The experimental samples include different molecular average weights of guaiacol, lignosulfonate and alkali lignin solutions. Controlling for different ozone dosages, HGRPB rotation speeds and pH levels, the COD, TOC, monomer concentrations and molecular average weights are measured and used to calculate the average reduction of contaminants per gram of ozone in the system. In the base case of 0.1 g/L of guaiacol solution, HGRPB is set at 5400 rpm and the reacting condition at pH 7. After 30 min of treatment time, 6 g/hr ozone dosage removes 13% more of COD, 12% more of TOC and 5% more of concentration than the standard 1 g/hr ozone dosage. This result indicates that the higher ozone dosage has the more contaminant removal. While controlling for higher HGRPB rotation speed at 7200 rpm yields 4% more of COD, 6% more of TOC and 6% more of concentration reduces. Higher rotation speed produces better removal results at the initial phase of treatment. 30 min of reaction under alkali conditions further reduce COD by 13%, TOC by 11% and the concentration by 5% more. Ozone is presumed to increase free radical under alkali condition and affects the oxidation of organic substances in water. Under identical condition, monomers with lower molecular average weights yield much higher reduction than the other two macromolecular compounds. The molecular average weights of the macromolecular compound solutions fluctuate with changes in COD and TOC. Under standard parameters, the molecular average weights of 0.1 g/L of lignosulfonate and alkali lignin solutions respectively reduce from 12030 to 1147 and from 60148 to 7093. Increasing ozone dosage, HGRPB rotation speed and alkali level yield more reduction of molecular average weights.