Ammonium-Functionalized Hollow Polymer Particles As a pH-Responsive Adsorbent for Selective Removal of Acid Dye

Abstract

In this work, a novel type of ammonium-functionalized hollow polymer particles (HPP-NH3(+)) with a high density of ammonium groups in the shell has been specially designed and synthesized. Benefiting from both the high surface area and from the high density of positively charged ammonium groups, the as-prepared HPP-NH3(+) can serve as a selective adsorbent for the removal of negatively charged acid dye (e.g., methyl blue a-MB). The equilibrium adsorption data of a-MB on the HPP-NH3(+) were evaluated using Freundlich and Langmuir isotherm models, and Langmuir isotherm exhibited a better fit with a maximum adsorption capacity of 406 mg/g. Most importantly, because of the presence of dual functional groups (ammonium and carboxyl groups), the HPP-NH3(+) showed a significant pH-dependent equilibrium adsorption capacity, which increased dramatically from 59 mg/g to 449 mg/g as the solution pH decreased from 9 to 2. This uniqueness makes the dye-adsorbed HPP-NH3(+) can be facilely regenerated under mild condition (in weak alkaline solution, pH 10) to recover both a-MB and the HPP-NH3(+), whereas the recovery of conventional adsorbents is commonly performed under particularly severe conditions. The regenerated HPP-NH3(+) can be reused for dye removal and the dye removal efficiency remained above 98% even after five adsorption-desorption cycles. Because of its high adsorption capacity, pH-sensitivity, easy regeneration, and good reusability, the HPP-NH3(+) has great potential for the application in the field of water treatment, controlled drug release, and pH-responsive delivery.

Dye-Mediated Interactions in Chitosan-Based Polyelectrolyte/Organoclay Hybrids for Enhanced Adsorption of Industrial Dyes

“…Effective, fast dye removal is essential prior to effluent discharge 8 . Among the conventional dye-effluent treatment techniques, adsorption to a solid substrate is one of the more economical and viable methods 9,10 . Characteristics include excellent affinity towards target dye molecules, high adsorption capacities and the possibility of adsorbent regeneration influence the selection of adsorbents employed 11 .…”

Adsorption of Malachite Green Dye from Liquid Phase Using Hydrophilic Thiourea-Modified Poly(acrylonitrile-co-acrylic acid): Kinetic and Isotherm Studies

“…Once hydrophobic nitrile groups containing polymer is prepared, dipole of nitrile groups can be modified into thioamide groups via postpolymerization. Nitrile groups can also be converted to amidoxime, amine, hydrazine, amidrazone, and carboxyl groups by the above similar chemical modification route [18,19,[21][22][23]. For instance, Kampalanonwat and Supaphol report the modification of polyacrylonitrile (PAN) with NaOH ethanolic solution for metal ion adsorption, although it is a costly and complicated process [24].…”

Effect of neighboring groups on the pH responsive adsorption/desorption behaviors of carboxylate functionalized hollow polymer particles

“…In our previous work, for the sake of better regeneration and reuse of the carboxylate HPPs, amino groups with opposite property were introduced onto the surface of the adsorbent . Although the adsorption capacity of b ‐MB decreased dramatically from 1603 to 363 mg g −1 , the as‐prepared bi‐functional HPPs (BF‐HPPs) exhibited significant pH‐sensitive adsorption capacity, remarkably high desorption rate and facile regeneration.…”