Low-cost hydrogel adsorbent enhanced by trihydroxy melamine and β-cyclodextrin for the removal of Pb(II) and Ni(II) in water

• Published in: Journal of hazardous materials 2021-06, Vol.411, p.125029-125029, Article 125029
• Main Authors: Wang, Zhike, Li, Ting-Ting, Peng, Hao-Kai, Ren, Hai-Tao, Lou, Ching-Wen, Lin, Jia-Horng
• Format: Article
• Language: English
• Subjects: Adsorption; Hydrogels; Strength optimization; β-cyclodextrin
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2020.125029

Hydrogels have extensively studied as adsorbents, raw materials for the preparation of adsorbent hydrogels have low strength, while high strength hydrogels have weak adsorption capacity. In this study, PVA hydrogel was crosslinked via trihydroxy melamine and epichlorohydrin, and β-cyclodextrin with strong adsorption capacity was added to remove the heavy metal ions. Results showed that the addition of trihydroxy melamine with 8%, the compressive strength of the hydrogel was increased by approximately 20%. The Langmuir isotherm model showed that the adsorption capacity of the hydrogel for Pb(II) and Ni(II) reached 505.9 mg/g and 286.7 mg/g, respectively, and the efficiency of removing the low-concentration heavy metal ions in water more than 99%. The hydrogel is low cost, and maintained highly removal efficiency under low pH. The removal efficiency of the hydrogel remained above 90% after five repeated adsorption-desorption experiments. The hydrogels have a potential to be used in wastewater treatment as adsorbents. [Display omitted] •The hydrogel can quickly and effectively adsorb heavy metal ions.•Optimized hydrogel strength using response surface design and trihydroxymelamine.•The hydrogel exhibits a fast adsorption rate and ultra-high adsorption capacity.•The preparation process of the hydrogel is simple and the cost is low.