去除水中懸浮顆粒之方法

專利類型

發明

專利國別 (專利申請國家)

中華民國

專利申請案號

094113788

專利證號

I 250044

專利獲證名稱

去除水中懸浮顆粒之方法

專利所屬機關 (申請機關)

國立臺灣大學

獲證日期

2006/03/01

技術說明

共沉澱反應為鋁鹽混擬去除氟離子的主要機制，當氫氧根離子與鋁離子的莫爾濃度比值(γOH)加上氟離子與鋁離子的莫爾濃度比值(γF)接近3時，氟離子的去除率會接近100%，這種現象表示氟離子與氫氧根離子可與鋁離子形成一種化學式為AlnFm(OH)3n-m的共沉澱物。然而，實驗結果顯示當γOH小於2.4時，此共沉澱物無法穩定存在。於是當γOH小於2.4時，氟離子的去除率會隨γOH的減少而遞減。 由於電膠羽浮除法去除氟化鈣顆粒的浮除效果不足，本研究將12烷基磺酸鈉(SDS)加入鈣鹽沉澱後的氟系廢水中，以增進電膠羽浮除的浮除能力。在此系統中，溶解性的氟離子及氧化鈣顆粒能被同時去除，且其所需要的SDS劑量小於空氣浮除法。這是因為在電膠羽浮除法中鋁膠羽可以捕捉大部分的氟化鈣顆粒，故SDS主要的作用為使氣泡小而穩定的起泡劑，而不需作為收集顆粒的捕集劑。在此系統的共存陰離子干擾可藉由增加鈣鹽及SDS劑量加以克服。廢水中的酸度則可藉由改變[Ca(OH)2]/[Ca2+]T比值的方式加以調整，其最佳的[Ca(OH)2]/[Ca2+]T比值可藉由氫氟酸的解離常數與初始pH值求得。 The results show coprecipitation is the major mechanism for fluoride removal for aluminum coagulation. The efficiency of defluoridation was approximately 100% when the sum (γOH+F) of the molar ratio of hydroxide (γOH) and fluoride ions (γF) to Al(Ⅲ) ions and was close to three. This finding reveals that the fluoride ions and the hydroxide ions co-precipitate with Al(Ⅲ) ions and the formula of the precipitate is AlnFm(OH)3n-m. However, when γOH is less than 2.4, the co-precipitate is not stable. Therefore, the deflouridation efficiency, given γOH+F =3, dropped as γOH fell, as γOH was less than 2.4. An anodic surfactant, sodium dodecyl sulfate (SDS), was employed to improve the flotation performance of the electro-coagulation-flotation (ECF) process to treat fluoride containing semiconductor wastewater following calcium precipitation. The dissolved fluoride ions and CaF2 particles in the wastewater after calcium precipitation were effectively removed in ECF process simultaneously. The dosage of SDS required for ECF was mush less than those for dispersed air flotation (DiAF) or dissolved air flotation (DAF) processes because the CAF2 particles can be collected by hydro-fluoro-aluminum flocs in ECF. Thus, SDS is only served as a frother to make the bubble tiny and stable in ECF defluoridation processes. The interference of co-existing anions can be overcome by increasing the dosage of calcium ions and SDS. The initial acidity of the wastewater after calcium precipitation can be modified by changing the [Ca(OH)2]/[Ca2+]T ratio and the appropriate ratio is approximately given by the acid dissociation constant of hydrofluoric acid and the initial pH of the wastewater before calcium precipitation.

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本部(收文號1100067353)同意該校110年11月5日校研發字第1100080471號函申請終止維護專利(台大)

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