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Adsorption of Sr(II) from water by mercerized bacterial cellulose membrane modified with EDTA

Cheng, Rong, Kang, Mi, Zhuang, Shuting, Shi, Lei, Zheng, Xiang, Wang, Jianlong
Journal of hazardous materials 2019 v.364 pp. 645-653
EDTA (chelating agent), Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, adsorbents, adsorption, cellulose, kinetics, mercerization, models, moieties, scanning electron microscopy, sorption isotherms, strontium, tertiary amines, wastewater
The treatment of low-level radioactive wastewater is a critical and considerable challenge. Bacterial cellulose membrane (BCM) modified with ethylenediaminetetraacetic acid (EDTA) using (3-aminopropyl) triethoxysilane (APTES) as a crosslinker were used to remove Sr2+ in this work. SEM, XPS, and FTIR were used to characterize the morphology, structure, chemical shift, and functional groups of the as-prepared adsorbent. The synthesized BCM@APTES-EDTA presented a three-layer structure of membrane-net-membrane with nano-sized fibers (<100 nm). The adsorption of Sr2+ onto BCM@APTES-EDTA was investigated as a function of contact time and initial concentration of Sr2+. Results showed that the adsorption of Sr2+ followed the pseudo second-order kinetic model (R2 = 0.999), and fitted well with the Langmuir isotherm model (R2 = 0.996). The maximum adsorption capacity was calculated to be 44.86 mg g−1, which was comparable to other adsorbents. Additionally, the mechanism of Sr2+ adsorbed by the as-prepared adsorbent was studied through FTIR and XPS analysis, which indicated that the tertiary amines and carboxylate from grafted EDTA participated in the adsorption of Sr2+.