Sun Wanhong, Zhang Wenbo, Li Hailing, Su Qiong, Zhang Ping, Chen Lihua
Department of Experimental Teaching, Northwest Minzu University Lanzhou 730030 P. R. China
School of Chemical Engineering, Northwest Minzu University Lanzhou 730030 P. R. China.
RSC Adv. 2020 Feb 28;10(15):8790-8799. doi: 10.1039/c9ra08756g. eCollection 2020 Feb 27.
Polypyrrole-based (PPy) composite are promising candidates for the treatment of water pollution. Adsorption selectivity as well as a large adsorption capacity are two key factors for treating wastewater containing multiple ions. The structure and morphology of the prepared composites were characterized by the FT-IR, XRD and SEM examinations. The results indicate that the FeO and PPy nanosphere coats attapulgite (ATP) closely and evenly. Herein, a novel FeO and ATP doped three-dimensional network structure PPy/FeO/ATP composite was demonstrated as an excellent adsorbent to effectively remove Cr(vi). The as-synthesized PPy/FeO/ATP composite is suitable for Cr(vi) adsorption in a wide pH range (pH 2-6). Up to a 96.44% removal rate was found with 400 mg L Cr(vi) aqueous solution in 30 min for 0.2 g PPy/FeO/ATP adsorbent. Adsorption results showed that Cr(vi) removal efficiency by PPy/FeO/ATP decreased with an increase in pH. The removal rate of Cr(vi) had already reached 93.63% in 15 min contact time. Co-existing ions studies exhibit inorganic oxyacid anion and transition metal cation showed negative effects on Cr(vi) removal rate. A chemical rather than a physical adsorption occurred for these adsorbents as revealed by a pseudo-second-order kinetic study. The results of the adsorption isotherms showed that the adsorption process was similar to the Langmuir isotherm adsorption. Furthermore, the PPy/FeO/ATP composite exhibited a high stability for Cr(vi) adsorption during recycling tests process. This work may provide some useful guidelines for designing adsorbents with selectivity toward specific heavy metal ions.
基于聚吡咯（PPy）的复合材料是处理水污染的有前途的候选材料。吸附选择性以及大吸附容量是处理含多种离子废水的两个关键因素。通过傅里叶变换红外光谱（FT-IR）、X射线衍射（XRD）和扫描电子显微镜（SEM）检查对制备的复合材料的结构和形态进行了表征。结果表明，FeO和PPy纳米球紧密且均匀地包覆在凹凸棒石（ATP）上。在此，一种新型的FeO和ATP掺杂的三维网络结构PPy/FeO/ATP复合材料被证明是一种能有效去除Cr（Ⅵ）的优良吸附剂。合成的PPy/FeO/ATP复合材料在较宽的pH范围（pH 2-6）内适用于Cr（Ⅵ）吸附。对于0.2 g PPy/FeO/ATP吸附剂，在30分钟内对400 mg/L Cr（Ⅵ）水溶液的去除率高达96.44%。吸附结果表明，PPy/FeO/ATP对Cr（Ⅵ）的去除效率随pH升高而降低。在15分钟的接触时间内，Cr（Ⅵ）的去除率已达到93.63%。共存离子研究表明无机含氧酸阴离子和过渡金属阳离子对Cr（Ⅵ）去除率有负面影响。伪二级动力学研究表明，这些吸附剂发生的是化学吸附而非物理吸附。吸附等温线结果表明，吸附过程类似于朗缪尔等温线吸附。此外，PPy/FeO/ATP复合材料在循环测试过程中对Cr（Ⅵ）吸附表现出高稳定性。这项工作可能为设计对特定重金属离子具有选择性的吸附剂提供一些有用的指导。
