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Preparation of a novel iron oxide/chitosan composite nanofiber and its adsorption of arsenate from water

基金项目：福建省科技计划工业科技重点项目(No.2013H0054);宁波市自然科学基金项目(No.2013A610175); 中国科学院"百人计划"项目

摘要：采用高压静电纺丝方法,制备了新型铁氧化物/壳聚糖复合纳米纤维砷吸附剂.扫描电子显微镜(SEM)观察结果显示,该纳米纤维的平均直径为(158±24)nm.X射线衍射谱图(XRD)表明,该纳米纤维为无定形结构.所制备的吸附剂在弱酸性或中性条件下对砷吸附率大于93%;吸附速率快,100 min内可达到吸附平衡;吸附剂对低浓度砷有很强的吸附亲和力,可将初始浓度为750 μg · L^-1的砷降低到10 μg · L^-1以下的安全饮用水水平;中性条件下吸附砷的最大容量为7.1 mg · g^-1,吸附等温线符合Freundlich模型;有机质对吸附的影响较小;吸附剂可用低浓度NaOH洗脱再生.研究结果表明,该吸附剂制备方法简单,易分离再生,在饮用水除砷领域有较好的应用前景.

Abstract：In this study, a novel iron oxide/chitosan composite nanofiber was synthesized as adsorbent for arsenate removal from aqueous environment. The adsorbent was characterized by SEM and XRD. Batch adsorption experiments were carried out to investigate the capability of the adsorbent for As(V)removal. The adsorbent was amorphous with a mean diameter of (158 ± 24)nm. Adsorption kinetics study showed that the adsorption equilibrium was obtained within 100 min. Pseudo-second-order kinetics model could be used well to describe the adsorption process. Isotherm study demonstrated that the residual arsenic could be easily reduced to below 10 μg · L^-1 by 0.2 g · L^-1 adsorbent when initial As(V)concentration was 750 μg · L^-1. The experimental adsorption isotherm data could be well described by the Freundlich isotherm model, and the maximum adsorption capacity calculated by Langmuir model was 7.1 mg · g^-1 at pH 7.0. Low concentration of humid acid didn't obviously affect the adsorption of arsenate by the adsorbent. Moreover, the arsenate loaded nanofiber could be easily separated, and regenerated by 0.002 mol · L^-1 NaOH solution. We can rationally expect this novel electrospun nanofiber to be an economical and effective adsorbent for the removal of trace As(V) from aqueous environment.