Department of Chemistry, University of Saskatchewan , 110 Science Place, Saskatoon, Saskatchewan S7N 5C9, Canada.
Water Science and Technology Directorate, Environment and Climate Change Canada , 11 Innovation Boulevard, Saskatoon, Saskatchewan S7N 3H5, Canada.
ACS Appl Mater Interfaces. 2016 Dec 7;8(48):33197-33209. doi: 10.1021/acsami.6b11504. Epub 2016 Nov 21.
Self-assembled and cross-linked chitosan/cellulose glutaraldehyde composite materials (CGC) were prepared with enhanced surface area and variable morphology. FTIR, CHN, and C solid state NMR studies provided support for the cross-linking reaction between the amine groups of chitosan and glutaraldehyde; whereas, XRD and TGA studies provided evidence of cellulose-chitosan interactions for the composites. SEM, equilibrium swelling, and nitrogen adsorption studies corroborate the enhanced surface area and variable morphology of the cross-linked biopolymers. Equilibrium sorption studies at alkaline conditions with phenolic dyes, along with single component and mixed naphthenates in aqueous solution revealed variable uptake properties with the composites. The Freundlich isotherm model revealed that the composite at the highest levels of cross-linker, CGC3, had the highest sorption affinity (K; L mmol/g) for phenolphthalein (phth) followed by ortho-nitrophenyl acetic acid (ONPAA) and para-nitrophenol (PNP), as follows: Phth (5.03 × 10) > ONPAA (2.28 × 10) > PNP (8.49 × 10). The Sips isotherm model provided a good description of the sorption profile of single component and naphthenate mixtures. The monolayer uptake capacity (Q; mg g) is given in parentheses: 2-hexyldecanoic acid (S1; 115 mg/g) > 2-naphthoxyacetic acid (S3; 40.5 mg/g) > trans-4-pentylcyclohexylcarboxylic acid (S2; 13.7 mg/g). By comparison, the Q values for CGC3 with naphthenate mixtures (24.1 and 27.4 mg/g) according to UV spectroscopy and electrospray ionization mass spectrometry (ESI-HRMS). The sorbent materials generally show greater uptake with naphthenates that possess lower vs higher double bond equivalence (DBE) values. Kinetic studies revealed that the sorption of phth adopted behavior described by the pseudo-second order model, while uptake for S3 and naphthenate mixtures adopted pseudo-first order behavior. This study contributes to a greater understanding of the sorption properties of the two types of abundant biopolymers and their composites by illustrating their tunable sorption properties. The key role of hydrophobic interactions for CGC materials was evidenced by the controlled sorptive uptake of carboxylate anions with variable molecular structure.
自组装和交联壳聚糖/纤维素戊二醛复合材料（CGC）具有增强的比表面积和可变的形态。FTIR、CHN 和 C 固态 NMR 研究为壳聚糖的胺基与戊二醛之间的交联反应提供了支持；而 XRD 和 TGA 研究则为复合材料中纤维素-壳聚糖相互作用提供了证据。SEM、平衡溶胀和氮气吸附研究证实了交联生物聚合物的增强比表面积和可变形态。在碱性条件下用酚类染料以及在水溶液中单一组分和混合环烷酸进行的平衡吸附研究表明，复合材料具有可变的吸附性能。Freundlich 等温模型表明，在交联剂水平最高的复合材料 CGC3 中，对酚酞（phth）的吸附亲和力（K；L mmol/g）最高，其次是邻硝基苯乙酸（ONPAA）和对硝基苯酚（PNP），如下所示：Phth（5.03×10）>ONPAA（2.28×10）>PNP（8.49×10）。Sips 等温模型很好地描述了单一组分和环烷酸盐混合物的吸附曲线。单层吸附容量（Q；mg/g）用括号表示：2-己基癸酸（S1；115mg/g）>2-萘氧基乙酸（S3；40.5mg/g）>反-4-戊基环己基羧酸（S2；13.7mg/g）。相比之下，根据紫外光谱和电喷雾电离质谱（ESI-HRMS），CGC3 与环烷酸盐混合物的 Q 值为 24.1 和 27.4mg/g。吸附材料通常对双键等价（DBE）值较低的环烷酸具有更大的吸附能力。动力学研究表明，phth 的吸附采用准二级动力学模型描述，而 S3 和环烷酸盐混合物的吸收采用准一级动力学模型。本研究通过说明其可调吸附性能，为更好地了解这两种类型的丰富生物聚合物及其复合材料的吸附性能做出了贡献。通过控制具有可变分子结构的羧酸根阴离子的吸附，证明了疏水相互作用对 CGC 材料的关键作用。
