Preparation of thermosensitive, calix[4]arene incorporated P(NIPAM‐co‐HBCalix) hydrogel as a reusable adsorbent of nickel(II) ions

Abstract

A calix‐conjugated thermo‐responsive hydrogel containing 15% tetra(5‐hexenyloxy)‐p‐tert‐butylcalix[4]arene (HBCalix), P(NIPAM‐co‐HBCalix), was used to remove nickel(II) ions from water. Both thermo‐sensitive properties and the Ni2+‐adsorption capabilities of the prepared P(NIPAM‐co‐HBCalix) hydrogels are investigated. Introduction of the monomer HBCalix considerably enhanced the adsorption of Ni2+ onto the hydrogel by chelation between hexenyloxy groups and metal ion. When HBCalix units capture Ni2+ and forms HBCalix/Ni2+ host–guest complexes, the lower critical solution temperature of the hydrogel shifts to a higher temperature due to both the repulsion between charged HBCali/Ni2+ groups and the osmotic pressure within the hydrogel. Adsorption studies were carried out by varying contact time, counter ion and initial concentration of Ni2+. The evaluation of adsorption properties showed that the hydrogel exhibited better correlation with Langmuir isotherm model. P(NIPAM‐co‐HBCalix) could be used repeatedly with little loss in adsorption capacity by simply changing the environmental temperature. This kind of ion‐recognition hydrogel is promising as a novel adsorption material for adsorption and separation of Ni2+ ions. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 2401–2408

Adsorption and Desorption of Na⁺ and NO₃⁻ Ions on Thermosensitive NIPAM-<i>co</i>-DMAAPS Gel in Aqueous Solution

“…This challenge can be met by the incorporating adsorbent containing ligands that enable show the high adsorption capacity of heavy metal ions. Recently many works have been done to investigate the specific material as a potential candidate for the application of adsorbent [6][7][8].…”

Smart Adsorbents for Aquatic Environmental Remediation

“…[94] This may be due to the higher LCST temperature of the copolymer PNIPAM/alginate compared to pure PNIPAM because of the presence of the more hydrophilic alginate, [94] a finding corroborated in a previous study. [103] Studies pertaining to the use of PNIPAM for improving adsorption of contaminants from aqueous solutions are summarized in Table 1.…”

Fabrication and Optimization of the Thermo-Sensitive Hydrogel Carboxymethyl Cellulose/Poly(N-isopropylacrylamide-co-acrylic acid) for U(VI) Removal from Aqueous Solution

“…The P(NIPAM-co-BACm) hydrogel adsorbed Pb 2+ at a temperature lower than the LCST and desorbed Pb 2+ at a temperature higher than the LCST. The calic-conjugated thermo-responsive poly(N-isopropylacrylamide-co-tetra(5-hexenyloxy)-p-tertbutylcalix [4]arene) (P (NIPAM-co-HBCalix)) has also been manufactured for capturing Ni 2+ , and its adsorption capacity was maintained above 90% after five cycles of adsorption-desorption [18].…”