Esquerdo V M, Cadaval T R S, Dotto G L, Pinto L A A
Unit Operation Laboratory, School of Chemistry and Food, Federal University of Rio Grande, FURG, Engenheiro Alfredo Huch Street, 475, 96201-900 Rio Grande, RS, Brazil.
Chemical Engineering Department, Federal University of Santa Maria, UFSM, Roraima Avenue, 1000, 97105-900 Santa Maria, RS, Brazil.
J Colloid Interface Sci. 2014 Jun 15;424:7-15. doi: 10.1016/j.jcis.2014.02.028. Epub 2014 Mar 12.
The dye adsorption with chitosan is considered an eco-friendly alternative technology in relation to the existing water treatment technologies. However, the application of chitosan for dyes removal is limited, due to its low surface area and porosity. Then we prepared a chitosan scaffold with a megaporous structure as an alternative adsorbent to remove food dyes from solutions.
The chitosan scaffold was characterized by infrared spectroscopy, scanning electron microscopy and structural characteristics. The potential of chitosan scaffold to remove five food dyes from solutions was investigated by equilibrium isotherms and thermodynamic study. The scaffold-dyes interactions were elucidated, and desorption studies were carried out.
The chitosan scaffold presented pore sizes from 50 to 200 μm, porosity of 92.2±1.2% and specific surface area of 1135±2 m(2) g(-1). The two-step Langmuir model was suitable to represent the equilibrium data. The adsorption was spontaneous, favorable, exothermic and enthalpy-controlled process. Electrostatic interactions occurred between chitosan scaffold and dyes. Desorption was possible with NaOH solution (0.10 mol L(-1)). The chitosan megaporous scaffold showed good structural characteristics and high adsorption capacities (788-3316 mg g(-1)).
与现有的水处理技术相比，壳聚糖对染料的吸附被认为是一种环保的替代技术。然而，壳聚糖用于去除染料的应用受到限制，因为其表面积和孔隙率较低。因此，我们制备了一种具有大孔结构的壳聚糖支架作为替代吸附剂，用于从溶液中去除食用色素。
通过红外光谱、扫描电子显微镜和结构特征对壳聚糖支架进行了表征。通过平衡等温线和热力学研究，研究了壳聚糖支架从溶液中去除五种食用色素的潜力。阐明了支架与染料之间的相互作用，并进行了解吸研究。
壳聚糖支架的孔径为50至200μm，孔隙率为92.2±1.2%，比表面积为1135±2 m² g⁻¹。两步朗缪尔模型适用于表示平衡数据。吸附是一个自发、有利、放热且受焓控制的过程。壳聚糖支架与染料之间发生了静电相互作用。用NaOH溶液（0.10 mol L⁻¹）可以实现解吸。壳聚糖大孔支架具有良好的结构特征和高吸附容量（788 - 3316 mg g⁻¹）。
