多孔陶瓷膜支撑体在HNO_3溶液中的腐蚀性能研究

为了考察陶瓷膜在苛刻体系中的应用性能,研究了管式多孔陶瓷膜支撑体(质量分数99%Al2O3)在硝酸溶液(温度20—90℃,浓度1—10 mol/L)中的微观结构演变、质量损失率、腐蚀掉的元素成分随时间的关系,以及支撑体的孔结构、纯水通量和机械强度随其质量损失率的变化关系。结果表明主要在支撑体颗粒间的烧结颈部发生了选择性的腐蚀,在腐蚀初期其质量损失主要是由于烧结颈部中Na,Ca,Al等元素的溶解。支撑体的耐腐蚀性能与其烧结颈部的杂质含量密切相关。多孔支撑体的机械强度随支撑体在HNO3溶液中的质量损失率增大而逐渐降低。所用的多孔陶瓷膜支撑体具有优异的耐腐蚀性能。该研究为进一步提高支撑体的耐腐蚀性能及预测陶瓷膜在酸性环境中的使用性能奠定了基础。

Study on corrosion behavior of porous supports of ceramic membrane in HNO3 solution

In order to investigate the application performance of ceramic membrane in harsh environment,the change of the mass loss rate with corrosion time,the microstructure evolution,strength degradation and changes in pore structure and pure water flux(PWF) of macroporous supports(mass fraction 99% Al_2O_3) immersed in HNO_3 solutions(1-10 mol/L and 20-90 ℃) were investigated experimentally.The results showed that the corrosion of supports in HNO_3 solution occurred mainly at the neck between Al_2O_3 particles.The selective dissolution in neck played an important role in the mass loss of tubular supports and the leached elements were mostly Ca,Na and Al.It is clarified that the corrosion resistance of support is closely related with the components at the neck between Al_2O_3 particles.The three-point bending strength of corroded macroporous supports decreases as the mass loss of support increases.These results provide the base for improving of corrosion resistance of support and forecasting the life span of ceramic membrane in acidic environment.