CPC/CaO_2氧缓释复合材料的制备及其释氧性能探讨

利用过氧化钙(CaO2)遇水释放氧气的特性,采用混合法将CaO2载入到磷酸钙骨水泥(CPC)中,并通过挤出-滚圆造粒方法制备出CPC/CaO2氧缓释复合材料,旨在为污染地下水的好氧生物修复技术提供一种长期、高效的供氧源。由X射线衍射(XRD)分析可知,通过固相反应制取的CPC主要成分为Ca5(PO4)3(OH)和Ca10(PO4)6(OH)2,具有较快的固化时间和固化效果;CPC/CaO2氧缓释复合材料分3个阶段进行释氧,其中2、3阶段分别符合一级和零级释氧动力学特征,且其释氧速率和释氧周期得到明显改善。本研究成果可用于实际地下水修复工程,解决污染地下水原位生物修复过程中溶解氧(DO)的输送问题。

Preparation and oxygen release properties of an oxygen slow-release composite (CPC/CaO2)

Calcium peroxide(CaO_2)is an emerging oxygen source for microbes in bioremediation of contaminated groundwater,but its rapid oxygen releasing velocity limits the engineering application of CaO_2.In this paper,calcium phosphate cement (CPC) was firstly synthesized from calcium phosphate,calcium carbonate and calcium hydrogen phosphate by solid reaction,and then self-setting CPC/CaO_2 composite was constructed by incorporating CPC and CaO_2.Phase composition of CPC is composed of Ca_5(PO_4)_3(OH) and Ca_10(PO_4)_6(OH)_2 with the examination of X-ray diffraction (XRD).The results of batch experiments showed that the oxygen-re-lease process of powdery CaO_2 and granular CPC/CaO_2 composite comprise three phases,and a first order kinetic equation can describe the second phase whereas a zero order model can be used to describe the third one.In addition,the oxygen releasing velocity of granular CPC/CaO_2 composite is obviously slower than that of powdery CaO_2,which will be useful for the application of CPC/CaO_2 composite in bioremediation of contaminated ground-water.