A Poly(Acrylic Acid)-Based Hydrogel Crosslinked with Hydroxypropylcellulose as a Clarifying Agent in Nickel(II) Solutions
Poly(acrylic acid) (PAA) and hydroxypropylcellulose (HPC) hydrogels were synthesized in the absence of a crosslinker. Chemical crosslinking between PAA and HPC was demonstrated through free radical polymerization by a precipitation reaction in acetone as the solvent. These hydrogels exhibited smalle...
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| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-07-01
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| Series: | Gels |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2310-2861/11/7/560 |
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| Summary: | Poly(acrylic acid) (PAA) and hydroxypropylcellulose (HPC) hydrogels were synthesized in the absence of a crosslinker. Chemical crosslinking between PAA and HPC was demonstrated through free radical polymerization by a precipitation reaction in acetone as the solvent. These hydrogels exhibited smaller swelling ratios (1 to 5 g H<sub>2</sub>O/g) than homo PAA hydrogels synthesized in water as the solvent. They were swollen in a 0.1 M NaOH solution and subsequently used to remove Ni<sup>2+</sup> ions from aqueous solutions with concentrations ranging from 1000 to 4000 ppm. The absorption capacity of these hydrogels ranged from 91 to 340 mg of Ni<sup>2+</sup>/g in a rapid 1 h process, and from 122 to 435 mg of Ni<sup>2+</sup>/g in a 24 h process, demonstrating an improvement in Ni<sup>2+</sup> absorption compared to previously reported hydrogels. The colored 1000 and 2000 ppm Ni<sup>2+</sup> solutions became clear after treatment, while the PAA-HPC hydrogels turned green due to the uptake of Ni<sup>2+</sup> ions, which were partially chelated by carboxylate groups as nickel polyacrylate and partially precipitated as Ni(OH)<sub>2</sub>, resulting in an average absorption efficiency of 80%. The hydrogel was able to release the absorbed Ni<sup>2+</sup> upon immersion in an HCl solution, with an average release percentage of 76.4%, indicating its potential for reuse. These findings support the use of PAA-HPC hydrogels for cleaning Ni<sup>2+</sup>-polluted water. The cost of producing 1 g of these hydrogels in laboratory conditions is approximately 0.2 USD. |
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| ISSN: | 2310-2861 |