外加電場薄膜程序處理染整廢水之研究

Abstract

摘要 本研究以外加電場來提升薄膜過濾程序，用來處理合成染料廢水之研究，並以染料Acid red 4、acid orange 10、Acid red 27調配成合成染整廢水，經不同電場以及不同pH來研究其通量以及去除率的變化；於施加電場的情況下，以超過濾(UF)處理合成染料廢水，過濾通量隨電場強度增加而增高，而價數越大的Acid red 27染料其電泳動能力越大，對色度及有機物之去除效率也較大；染料在高pH情況下，電泳動能力大，去除效率也較大;薄膜積垢阻力藉由施加電場所引起電泳動作用，可有效減少總積垢阻力及不可逆阻力的比例；外加電場的通量與電場強度成正相關，而臨界電場對於通量的效率，則是操作條件的關鍵指標。在對色度及有機物去除率方面隨電場強度比(E/Ec)增高而提升，故在外加電場程序中，有效電場強度(E)與臨界電場(Ec)的比值，有其相關的意義。 在外加電場薄膜程序中，所用的操作條件以及所使用的薄膜，經電滲透實驗顯示電滲透的效應不明顯，而在98KPa壓力操作下，也僅增加6%的通量貢獻，顯示外加電場程序通量之提升主要來自電泳作用；薄膜過濾染料的效果主要受到染料基本性質的影響，包括分子量大小、電泳動能力與染料對薄膜的吸附能力。 由合成染料廢水與實廠染整廢水的外加電場薄膜處理比較可知，顯示實廠廢水因為製程和混凝的加藥，使得總溶解性固體大幅增加，而有著導電度過高的現象，使得外加電場薄膜程序，會消耗相當大的電量達到臨界電場，都會造成此外加電場薄膜程序的不經濟；本研究之初步經濟分析顯示，外加電場薄膜程序處理染整廢水，針對低導電度及高電泳動能力之廢水將有較佳的經濟優勢。

Abstract The propose of the study to combine the electric driving force and membrane process to enhance the performance of ultrafiltration(UF) system. An experiment who conducted to evaluate the electrically enhanced ultrafiltration was a synthetic dye solution. Acid red 4, acid orange 10 and Acid red 27 were used in the experiment to prepare the synthetic dye and salt mixtures.While treating the waste water of synthesized dye by UF under the application of electric field, the increase of filtration flux would be resulted with the augmentation of the intensity in electric field.The Acid red 27 dye with higher valence number has stronger electrophoresis mobility, and has higher efficiency on the removal of color and organic substances. Under higher pH, dye has stronger electrophoresis mobility and better treatment efficiency. Due to the electrophoresis effect induced by the applied electric field, the fouling resistance of membrane could reduce total fouling resistance and irreversible resistance effectively. The flux of filtration and the intensity of electric field have positive correlation, and the critical electric field is the key to the operation condition revelant to the flux. As for the efficiency in the elimination of color and organic substances were increased with higher of E/Ec, so the ratio of effective electric field(E) to critical electric field(Ec) is meaningful in the process of applied electric field. In the process of electro-membrane filtration, the applied operation condition and membrane do not have significant electroosmosis effect through related experiment. Under the operation of 98KPa pressure, only 6% flux was increased, which showed the increase of flux in the applied electric field process mainly from electrophoresis effect. The effect of dye filtration by membrane is mostly influenced by the basic nature of dye, including size of molecular weight, electrophoresis motility and the adsorbability of dye to membrane. As compared the electro-membrane filtration treatment in synthesized dye waste water with the textile waste water, it showed the TDS increased substantially in textile waste water due to chemical addition in production and coagulation processes. As a result there is the phenomenon of over electric conductivity content in the process of electro-membrane filtration,and a significant electricity is consumed in order to critical electric field.Also, the consequeuce is that the electro-filtration becomes an uneconomical process. According to the preliminary economical analysis by this research, the electro-membrane filtration process has an economic advantage over the ordinary membrane process, when the dye-containing waste water has low electric conductivity and high electrophoresis mobility.