Synthesis and characterization of poly(TRIM/VPA) functionalized graphene oxide nanoribbons aerogel for highly efficient capture of thorium(IV) from aqueous solutions

• Published in: Applied surface science 2021-01, Vol.536, p.147829, Article 147829
• Main Authors: Wang, Yun, Chen, Xinchen, Hu, Xuewen, Wu, Peng, Lan, Tu, Li, Yang, Tu, Hong, Liu, Yan, Yuan, Dingzhong, Wu, Zhenyu, Liu, Zhirong, Chew, J.W.
• Format: Article
• Language: English
• Subjects: Adsorption; Aerogel; Graphene oxide nanoribbons; Phosphonic acid; Thorium(IV)
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2020.147829

[Display omitted] •Ultralight PAFP/GONRs-A aerogel was prepared facilely by solvothermal polymerization method.•The aerogel showed a low density, large specific surface area and high phosphorus content.•The aerogel presented an unexpectedly high adsorption capacity and selectivity for thorium.•Phosphonic groups play an important role in Th(IV) adsorption.•DFT calculations revealed the coordination modes of Th(IV) with the aerogel, confirming the experimental results. An ultralight three-dimensional porous network phosphonic acid functionalized polymer/graphene oxide nanoribbons aerogel (PAFP/GONRs-A) was prepared using trimethylolpropane trimethacrylate (TRIM) and vinylphosphonic acid (VPA) as monomers via solvothermal polymerization method for thorium capture from aqueous solutions. The synthesized aerogel presented a low density (10.6 mg cm−3), large specific surface area (433.2 m2 g−1) and high phosphorus content (18.2%). The adsorption process of Th(IV) on PAFP/GONRs-A was pH-dependent, spontaneous and endothermic, and well described by the pseudo-second-order kinetic and Langmuir isotherm model. Under optimal experimental conditions (10 mg of adsorbent dosage, 50 mL of solution volume, 240 min of contact time, 298 K of temperature), PAFP/GONRs-A presented an excellent high adsorption capacity of thorium, with maximum capacity of 457.9 mg g−1 at a pH of 3.0, and maximum thorium-selectivity of 87.1% at a pH of 2.0. The values of ΔG for Th(IV) adsorption on PAFP/GONRs-A were calculated to be −21.78, –23.32, −24.87 and −26.41 kJ mol−1 at 283, 298, 313 and 328 K, respectively. Density functional theory (DFT) calculations and X-ray photoelectron spectroscopy (XPS) revealed that Th(IV) ions were fixed in aerogel by coordinating with the P = O groups of PAFP/GONRs-A, and both 1:2 ratio of Th(IV) with the P = O ligands on the same graft chain and 1:4 ratio of Th(IV) with P = O ligands on two distinct graft chains could jointly contribute to the adsorption of Th(IV) on PAFP/GONRs-A. This work offers a facile approach for synthesizing the phosphonic acid functionalized graphene oxide nanoribbons aerogel and demonstrates that PAFP/GONRs-A has high potential as a candidate adsorbent for the capture of thorium from aqueous solution.