不同无机酸对聚吡咯/TiO_2复合物的吸附性能影响

The influence of various inorganic acids on the adsorption performance of the polypyrrole/TiO_2 composites

考察了不同无机酸对PPy/TiO_2复合物吸附性能的影响。首先分别在HNO3、H2SO4和H3PO4体系中合成了聚吡咯(PPy)/TiO_2复合物(分别简写为N-PPy/TiO_2、S-PPy/TiO_2和P-PPy/TiO_2)。以红外光谱、热重分析、Zeta电位、比表面积分析和扫描电镜等测试方法对复合物的物理化学性能进行了表征。接着以几种合成的复合对阴离子染料酸性红G和阳离子染料亚甲基蓝进行吸附研究,发现无机酸对合成的复合物的吸附性有较大的影响。几种复合物均可在30min内达到吸附平衡,并且可以重复使用6次以上吸附量没有明显的降低。其中S-PPy/TiO_2的吸附性能最好,其对ARG和MB的最大吸附量分别达到218.34mg/g和314.68mg/g。复合物对染料的吸附过程符合准二级动力学模型和Langmuir吸附等温式。对S-PPy/TiO_2进行吸附热力学研究表明,其对染料的吸附过程为熵增的自发过程。

This study focused on the impact of various inorganic acids on the adsorption polypyrrole/TiO_2(PPy/TiO_2)composites.Firstly,PPy/TiO_2 composites were prepared in the HNO_3(N-PPy/TiO_2)、H_2SO_4(S-PPy/TiO_2)and H3PO4(P-PPy/TiO_2)systems,respectively.FT-IR spectra,TG analysis,Zeta potential,specific surface area analysis and SEM were employed to character the physicochemical properties of the composites.Secondly,the adsorption of the as-prepared composites for anionic dye Acid red G(ARG)and cationic dye methylene blue(MB)were investigated.It was found that the adsorption performance of the composites prepared in acid system has been greatly improved.The adsorption equilibrium of all composites can reach in 30 min.The composites could be reused for 6 cycles without obvious loss of adsorption capacity.S-PPy/TiO_2 composite had the best adsorption properties.Its maximum adsorption capacity for ARG and MB were 218.34mg/g and 314.68mg/g,respectively.The adsorption process of dyes onto the composites was in accordance with pseudo-second-order models and Langmuir isotherm.The S-PPy/TiO_2 adsorption thermodynamics research showed that the adsorption process of dyes onto the composite was a spontaneous process of entropy increase.