蔗糖溶液中新生磷酸钙对单宁酸的吸附性能研究

研究了蔗糖溶液中新生磷酸钙对单宁酸的吸附特性。根据吸附动力学数据进行了粒内扩散模型、准一级动力学模型和准二级动力学模型的拟合,在蔗糖溶液中新生磷酸钙对单宁酸的吸附过程符合准二级动力学方程(R2=0.9994~0.9998),蔗糖分子的存在并不影响新生磷酸钙对单宁酸的吸附动力学行为,在不含蔗糖溶液中新生磷酸钙对单宁酸的吸附也符合准二级动力学方程(R2=0.9997~1.000)。新生磷酸钙对单宁酸的吸附呈单分子层吸附,符合Langmuir等温吸附模型(R2=0.9934~0.9963),蔗糖的浓度对吸附量有一定影响,在不含蔗糖体系中新生磷酸钙对单宁酸的吸附量最大,随着溶液中蔗糖浓度的升高,吸附量逐渐减小。当蔗糖溶液的浓度为分别为0.0%、5.0%、10.0%时,新生磷酸钙对单宁酸的饱和吸附量依次降低分别为125.00、91.74、86.96 mg/g。

Adsorption Characteristics of Tannic Acid on Fresh Calcium Phosphate in Sucrose Solution

The adsorption characteristics of tannic acid on fresh calcium phosphate in sucrose solution were discussed. Three kinetic models, including pseudo-first-order model, pseudo-second-order model and intraparticle diffusion model, were selected to model the adsorption processes. The adsorption of fresh calcium phosphate for tannic acid conformed to the pseudo-second order kinetic equation both in 10% sucrose solution and in the solution without sucrose, which showed that the existence of sugar molecules did not influence the adsorption dynamics model of fresh calcium phosphate. Adsorption isotherm curves of tannic acid from different concentrations of sucrose solution on fresh calcium phosphate all conformed to the Langmuir model. Sucrose concentration had certain influence on the adsorption quantity of fresh calcium phosphate for tannic acid, besides, the adsorption quantity of that in the system containing no sugar was the largest. With the increase of sucrose solution concentration, the adsorption quantity of fresh calcium phosphate to tannic acid gradually reduced.