Abstract

This study has focused on the applications of newly prepared zinc oxide (ZnO) composite with polyvinylpyrrolidone (PVP) for adsorptive removal of methyl orange and Congo red dyes. The performance of ZnO–PVP composite in removing the dyes from aqueous solution is almost double than the simple metal oxide, which signifies the role of PVP in the composite of metal oxide–PVP. The adsorption of methyl orange and Congo red onto ZnO–PVP composite was also conducted as a function of pH of solution, concentration, adsorbent dosage and temperature of the solution. The adsorption of methyl orange and Congo red onto ZnO–PVP composite decreased with the increase in pH of the mixture. The obtained adsorption capacity for methyl orange is higher than Congo red which is related to functional group and size of the dye. The values of ∆H and ∆G designate that adsorption of methyl orange and Congo red is endothermic in nature. The positive values of ∆S for methyl orange and Congo red confirmed a high disorder at the solid/liquid interface.

中文翻译：

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PVP官能化ZnO吸附水溶液中甲基橙和刚果红的热力学研究

摘要

这项研究的重点是将新制备的氧化锌（ZnO）与聚乙烯吡咯烷酮（PVP）复合用于吸附去除甲基橙和刚果红染料的应用。ZnO–PVP复合材料从水溶液中去除染料的性能几乎是简单金属氧化物的两倍，这表明PVP在金属氧化物–PVP复合材料中的作用。甲基橙和刚果红在ZnO-PVP复合材料上的吸附也随溶液的pH值，浓度，吸附剂量和溶液温度而变化。随着混合物pH值的增加，甲基橙和刚果红在ZnO-PVP复合材料上的吸附降低。所获得的甲基橙吸附能力高于刚果红，这与染料的官能团和大小有关。ΔH的值△ G表示甲基橙和刚果红的吸附本质上是吸热的。甲基橙和刚果红的∆ S正值证实了固/液界面处的高度无序。