Study on the selective adsorption of Ag+ by thermosensitive poly(n-isopropylacrylamide)/guanylthiourea/chitosan composites

Aili Niyazi; Chaoqun Mu; Ting Wang; Wangsheng Ye; Lvling Zhong; Zhixian He; Haoyang Xu; Zhiqiang Zhang; Liang Zhang

doi:10.1016/j.ijbiomac.2024.139182

Study on the selective adsorption of Ag⁺ by thermosensitive poly(n-isopropylacrylamide)/guanylthiourea/chitosan composites

Int J Biol Macromol. 2024 Dec 31:294:139182. doi: 10.1016/j.ijbiomac.2024.139182. Online ahead of print.

Authors

Aili Niyazi¹, Chaoqun Mu², Ting Wang¹, Wangsheng Ye¹, Lvling Zhong¹, Zhixian He³, Haoyang Xu¹, Zhiqiang Zhang⁴, Liang Zhang⁵

Affiliations

¹ School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China.
² School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China. Electronic address: chaoqunmu@xauat.edu.cn.
³ Instrumental Analysis Center, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China.
⁴ Department of Material and Chemical engineering, Zhengzhou University of Light Industry, Zhengzhou, Henan 450002, China.
⁵ School of Chemistry and Chemical Engineering, Xi'an University of Architecture and Technology, Xi'an, Shaanxi 710055, China. Electronic address: zl98zl@hotmail.com.

PMID: 39746415
DOI: 10.1016/j.ijbiomac.2024.139182

Abstract

In this work, temperature-responsive poly(N-isopropylacrylamide) (PNIPAM) and the ‌guanylthiourea (GLA) were used to modify chitosan (CS) to prepare a novel PNIPAM/GLA/CS adsorbent for Ag(I) ions. Temperature variations near the lower critical solution temperature (LCST) facilitate the adjustment of functional group distribution within the composite material, thereby influencing its adsorption performance for silver ions. The characteristics of this composite material were confirmed using a variety of techniques, including scanning electron microscopy (SEM), variable-temperature ultraviolet-visible near-infrared spectroscopy, Fourier-transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). Studies on the adsorption of Ag(I) ions by the PNIPAM/GLA/CS adsorbent indicated that the optimal pH for adsorption is 6.0. The adsorption kinetics were best described by the pseudo-second order kinetic model, while the equilibrium adsorption data aligned more closely with the Langmuir adsorption isotherm model, achieving a maximum adsorption capacity of 336.33 mg/g at 40°C. Experimental results demonstrated that higher adsorption amounts were observed above the LCST, while desorption of target ions was more favorable below the LCST. This research provides valuable insights for the design of new structural adsorbents.

Keywords: Adsorption; Chitosan; Poly(N-isopropylacrylamide); Thermoresponsive.