Evaluating Adsorptive Separation of Aniline from Aqueous Solution by an Aminated Hypercrosslinked Polymer
In the present work, a modified hypercrosslinked polymeric resin (AH-1) with tertiary amino groups was adopted for adsorbing aniline from aqueous solution, and a traditional hypercrosslinked polymeric adsorbent NDA-100 was selected for comparison. Favorable aniline adsorption was observed at higher solution pH in the range of 5-11, and a further decrease of solution pH resulted in a marked decrease of adsorption capacity. The fact that AH-1 had higher adsorption capacity than NDA-100, would be attributed to the enhanced adsorbent-adsorbate interaction for tertiary amino group introduced on the polymeric matrix. The adsorption process was found to be exothermic and data conformed to the Freundlich equation. In addition, the adsorption kinetic study testified that a pseudo-second kinetic mechanism for the adsorption system, and the rate constant of AH-1 was larger than that of NDA-100. More favorable adsorption of aniline onto AH-1 than NDA-100 was further demonstrated by column adsorption runs which indicated that aniline could be effectively removed from aqueous solution by AH-1. Moreover, AH-1 exhibited a better desorption performance than NDA-100, nearly 100% regeneration efficiency for the spent AH-1 was achieved by 5% hydrochloric acid for its repeated use, implying its potential application in associated wastewater treatment.