盐酸浸取麦麸中植酸盐的研究

Study on Leaching of Phytin by Hydrochloric Acid

文题确定的最优工艺条件为:pH=5.25,T=60℃,适当搅拌,避免碱土金属离子的存在。该条件下1h浸取量达7.0%。研究表明,间歇浸取为表观二级反应。动力学分析、导出并验证了过程的非稳态移动界面反应-扩散模型,确定反应处于盐酸产物层扩散控制,历时约3min。建立了浸取过程近似解析解,求出了盐酸和植酸盐的产物层有效扩散系数。

The process is studied for industrial development. It is found that the degrce of leaching highly depends on pH value and temperature. In the optimum condition when pH= 5.25, t= 60℃ and with moderate stir, the leached quantity reaches 7.0% (wt/wt) in 60 minutes. It is also found that the leached quantity decreases significantly when divalant cations exist in the solvent. The kinetic research shows that the chemical reaction is apparently of second order with respect to hydrochloric acid and continues about 3 minutes. The reaction is controlled by the diffusion of hydrogen ions through ash layer. On the other hand, the dissolved phytin diffuses much slower than other components so that the process can be simplified as one dimensional unsteady diffusion of the product through the ash layer. The approximate analytical solution is obtained and the efficient diffusion coefficients of hydrochloric acid and phytin in the ash layer are estimated, which turn out to be 1×10^(-10)m^2/s and 2,5×10^(-12) m^2/s respectively.