氨氮、硝酸盐氮和亚硝酸盐氮在PVA凝胶膜中的扩散性能

用冷冻-解冻法制备PVA凝胶膜,测定了氨氮、硝酸盐氮和亚硝酸盐氮在PVA凝胶膜中的扩散系数,考察了成膜条件和细胞密度对扩散系数的影响.结果表明,扩散系数随冷冻-解冻次数、PVA溶液的浓度及细胞密度的增大而减小. 氨氮、硝酸盐氮和亚硝酸盐氮在15% PVA的空白膜中的扩散系数分别为0.69×10^-9 m²/s, 0.52×10^-9m²/s和0.56×10^-9 m²/s; 在细胞浓度为60g/L的PVA膜中的扩散系数分别为0.55×10^-9 m²/s, 0.46×10^-9 m²/s和0.45×10^-9 m²/s.

Diffusion Coefficients of Ammonia, Nitrate and Nitrite in Cell-free and Cell-containing PVA Gel Membranes

The cell free PVA gel membrane and cell containing PVA gel membrane were prepared by iterative freezing and thawing, and the diffusion coefficients of ammonia, nitrate and nitrite in PVA gel membranes were determined. The effect of the conditions of preparing PVA gel membranes and cell concentration on the diffusion coefficients of ammonia in PVA gel membranes were investigated. The results shown the diffusion coefficients of ammonia in PVA gel membranes decreased while the iteration times of freezing thawing or PVA concentration or cell concentration increased. The diffusion coefficients of ammonia, nitrate and nitrite in cell free PVA gel membranes (PVA concentration was 15%) were 0.69×10^-9 m²/s, 0.52×10^-9 m²/s, and 0.56×10^-9 m²/s, respectively. The diffusion coefficients of ammonia, nitrate and nitrite in cell containing PVA gel membranes (the cell concentration was 60g/L) were 0.55×10^-9 m²/s, 0.46×10^-9 m²/s, and 0.45×10^-9 m²/s, respectively.