摘要 溶解性微生物產物(soluble microbial products, SMP)對薄膜生物反應器(membrane bioreactor, MBR)會造成明顯的積垢現象。本研究旨在探討微型(~500 nm) 磁性顆粒,是否可做為溶解性微生物產物之吸附劑。磁鐵(magnetite, Fe3O4)先以共沉澱方法製備,而後塗上聚甲基丙烯酸甲酯(polymethyl methacrylate, PMMA)進行表面官能基化。在溫度(40,60,80℃)及時間(2,4,6小時)下,採用原子轉移自由基聚合法(atom transfer radical polymerization, ATRP)及臭氧引起的自由基聚合法(ozone-induced free radical polymerization, O3-RP)之塗佈技術進行牛血清白蛋白(bovine serum albumin, BSA)吸附效果之批次試驗。研究結果發現PMMA表面塗佈磁鐵 (Fe3O4-PMMA) 比其原始形式具有較高之吸附能力。無論塗佈方法與塗佈時間長短,在80℃下塗佈之顆粒,具有最高之吸附能力(8到10毫克/克)。這可能是由於溫度對高分子塗佈量最具關鍵影響力。磁鐵礦具高回收性,研究發現有99.94%可於10分鐘內透過磁鐵吸咐從水中去除。磁性顆粒具有回收、處理、再利用,可作為多次吸附劑之潛力,可不斷去除SMP並 降低膜積垢。
Abstract Soluble microbial products (SMP) are biomolecules that have a significant impact on the fouling phenomenon of membrane bioreactors (MBR). In this study, micro-sized (~500 nm) magnetic particles were evaluated as a possible SMP adsorbent. Magnetite (Fe3O4) was prepared via co-precipitation method, and then coated with polymethyl methacrylate (PMMA) for surface functionalization. The effect of coating method (atom transfer radical polymerization, ATRP and ozone-induced free radical polymerization, O3-RP), temperature (40, 60, 80oC), and time (2, 4, 6 hr) on the adsorption of bovine serum albumin (BSA) was determined in batch tests. It was observed that magnetite coated with PMMA (Fe3O4-PMMA) had higher adsorption capacity than its pristine form. Particles coated at 80oC possessed the highest adsorption capacities (8 to 10 mg/g), regardless of coating method and time. This might be due to the fact that coating temperature has the most influence on the amount of coated polymer. Magnetite have high recoverability – it was found that 99.94% can be separated from water through magnet in as quickly as 10 min. Magnetic particles have potential to recovered, treated, and then re-used as adsorbent for multiple cycles, continuously separating SMP and reducing membrane fouling.