壳聚糖改性沸石对蔗糖溶液中酚酸的吸附性能研究

Adsorption of Phenolic Acids from Sucrose Solution on Chitosan Modified Zeolite

摘要:

为了降低制糖过程中蔗汁中酚类化合物的含量，本研究以壳聚糖和沸石为原料，通过共沉淀法制备壳聚糖改性沸石，研究改性前后沸石表面结构和基团的变化，考察时间、pH及酚酸初始浓度等因素对改性沸石吸附蔗糖溶液中酚酸吸附效果的影响，并对吸附动力学模型和吸附等温模型进行初步探讨。扫描电镜结果显示壳聚糖改性后沸石表面更加粗糙，红外光谱显示改性后复合材料基团发生了改变，壳聚糖成功地负载到了沸石上。吸附试验结果表明壳聚糖改性可以提高沸石对酚酸的吸附能力，改性沸石对酚酸吸附的最佳pH值为8.0，吸附时间为600 min，此时酚酸吸附量达到了33.41 mg/g；酚酸初始浓度的提高有利于提高吸附效果；吸附过程符合准二级吸附动力学模型和Langmuir等温吸附模型。壳聚糖改性沸石对蔗糖溶液中酚酸吸附效果良好，是一种有前景的糖用澄清剂。

Abstract:

In order to reduce the content of phenolic compounds in sugarcane juice, chitosan modified zeolite was prepared by coprecipitation method with chitosan and zeolite as raw materials. The changes of surface structure and group of zeolite before and after modification were studied, and the effects of time, pH and initial concentration of phenolic acid on adsorption of phenolic acid from sucrose solution by modified zeolite were investigated. The adsorption kinetic model and adsorption isotherm model were discussed. The results of SEM showed that the surface of the modified zeolite was more rough. The results of infrared spectrum showed that the group of the composite was changed after modification, and chitosan was successfully loaded on the zeolite. The results show that chitosan modification could improve the adsorption capacity of phenolic acid on zeolite. The optimal pH value of modified zeolite was 8.0 and the adsorption time was 600 min. The adsorption capacity of phenolic acid reached 33.41 mg/g. The increase of initial concentration of phenolic acid was beneficial to improve the adsorption effect. The adsorption process was agreed to the pseudo second order adsorption kinetic model and Langmuir isothermal adsorption model. Chitosan modified zeolite had a good adsorption effect on phenolic acid in sucrose solution and is a promising clarifying agent for sugar.