Facile assembly of three-dimensional cylindrical egg white embedded graphene oxide composite with good reusability for aqueous adsorption of rare earth elements

• Published in: Colloids and surfaces. A, Physicochemical and engineering aspects Vol. 570; pp. 127 - 140
• Main Authors: Xu, Xia, Zou, Jiao, Zhao, Xiao-Ru, Jiang, Xin-Yu, Jiao, Fei-Peng, Yu, Jin-Gang, Liu, Qi, Teng, Jie
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.06.2019
• Subjects: Adsorption; Egg white; Graphene oxide; Rare earth elements; Three-dimensional; Graphene oxide; Egg white; Three-dimensional; Adsorption; Rare earth elements
• ISSN: 0927-7757; 1873-4359
• DOI: 10.1016/j.colsurfa.2019.03.022

By using egg white (EW) as the structural support, the new 3D cylindrical GO-based composites were fabricated by one-step hydrothermal method. The 3D CEG composites were characterized, and their adsorption capabilities and possible adsorption mechanism toward REEs were investigated. The adsorption conditions were evaluated, and the adsorption thermodynamics, kinetics and isotherms were discussed in detail. The developed adsorbents were used for the removal of REEs in spiked environmental water samples including Yudai iver, Xiangjiang River, spring water and tap water with good spiked recoveries in the range 62.6–99.6%. The reusability of 3D CEG composites was accessed by five adsorption-desorption cycles. [Display omitted] A porous three-dimensional (3D) macrostructure was facilely fabricated by embedding egg white (EW) into graphene oxide (GO) (CEG) under hydrothermal condition. The microstructure, pore size distribution and surface compositions of CEG were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET) method, X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, thermogravimetric analysis (TGA) and Fourier transform infrared (FT-IR) spectroscopy. The as-prepared 3D CEG composite was used for the aqueous adsorption of rare earth elements (REEs) including La(III), Y(III), Yb(III), Er(III) and Nd(III) from aqueous solutions. The condition parameters such as contact time, initial REEs concentration, pH values and adsorption temperature were investigated. The adsorption could achieve equilibrium within 90 min and the adsorption of REEs onto 3D CEG1:1 composite fitted well to the pseudo second-order kinetics model and the Langmuir isotherm model. Thermodynamic and kinetic studies indicated that the adsorption process was endothermic and spontaneous in nature. The maximum adsorption capacities of 3D CEG1:1 composite were 42.80, 32.16, 56.44, 51.44 and 50.16 mg g−1 toward La(III), Y(III), Yb(III), Er(III) and Nd(III), respectively. The 3D CEG1:1 composite was used to remove the La(III), Y(III), Yb(III), Er(III) and Nd(III) from Yudai river water, Xiangjiang river water, spring water and tap water with spiked recoveries in the range 62.6–99.6%. The 3D CEG1:1 composite showed a good adsorption-desorption ability, and the percentage removal of 3D CEG1:1 composite for Yb(III) remained constant of 100% at a low Yb(III) concentration even after five cycles.