以聚乙烯醇與海藻酸共聚物乘載普魯士藍之顆粒去除水中之銫

Abstract

我們使用非輻射之銫-133來模擬輻射銫在水中的吸附行為，合成之聚乙烯醇與海藻酸共聚物顆粒為一良好之普魯士藍載體，此種顆粒在淡水、自來水、海水中被使用為銫離子之吸附劑，在吸附銫的同時，此種顆粒在吸附過程中保有良好的穩定性。鐵離子在吸附程序完成後的水體中被檢測出，代表普魯士藍在吸附過程中有微量的分解，而鐵血鹽在水體中是我們所不樂見的，此問題可以在聚乙烯醇與海藻酸共聚物顆粒中添加可以吸附目標離子之離子交換樹脂，達到同時吸附銫離子且同時吸附分解的目標離子，以防止它溶入水中。在杯瓶實驗中，銫離子被聚乙烯醇與海藻酸共聚物顆粒吸附為一顆粒內擴散質傳控制程序，換言之，顆粒內擴散為速率決定步驟，此結果被模型模擬所驗證，此外，隨著聚合物的聚合程度提高，顆粒內擴散係數將會隨之減低。本研究所使用的顆粒配方在快濾池模擬實驗中並無法將銫離子百分之百去除，但線性驅動力模型提供了可調整之參數，我們可以藉由調整這些參數去面對不同的需求。此研究提供了一種可在淡水及海水中去除銫且同時防止離子溶至水中之多功能顆粒，可做為核能事故發生時之緊急處理方案。

In this study non-radioactive Cs-133 was used to simulate the adsorption process of radioactive cesium in water.. ALG-PVA Prussian blue (PB) granule was synthesized and was used as an adsorbent to remove cesium in deionized water, tap water and sea water. The ALG-PVA granule can adsorb cesium efficiently from fresh and salty water.Some iron ions had eluted into the water, which means there some PB had dissolved, releasing ferrocyanide ion into the water. The ions can be removed by adding an ion exchange resin for selected target ion in the ALG-PVA PB granule. The adsorption of cesium in the batch test is an intraparticle diffusion control process confirmed by the model simulation result. The degree of crosslinking of polymer decreases the effective diffusivity of the granule. The current recipe of granule cannot remove all the cesium in large scale rapid filtration test which shows that one can get 100% removal of cesium by changing the radius of granule from 3mm to 2mm. This study provides a multi-function granule which can remove cesium from tap water, sea water and can prevent possible leakage of ion from PB as an emergent solution for nuclear accident.