Selective Adsorption and Efficient Removal of Phosphate from Aqueous Medium with Graphene–Lanthanum Composite

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• 作者：Mingli Chen ; Chunbao Huo ; Yikun Li ; Jianhua Wang
• 刊名：ACS Sustainable Chemistry & Engineering
• 出版年：2016
• 出版时间：March 7, 2016
• 年：2016
• 卷：4
• 期：3
• 页码：1296-1302
• 全文大小：402K
• ISSN：2168-0485

文摘

A three-dimensional adsorbent, i.e., lanthanum oxide decorated graphene composite (3D graphene–La<sub>2sub>O<sub>3sub> composite), is prepared. The composite exhibits favorable adsorption performance to phosphate, providing a sorption capacity of 82.6 mg g<sup>–1sup> at pH 6.2. The adsorption behavior for phosphate fits the Langmuir model, and the adsorption kinetics fit a pseudo-second-order model, with rate constants of 0.1847 and 0.007 969 g mg<sup>–1sup> min<sup>–1sup> at phosphate concentrations of 35 and 142 mg L<sup>–1sup>, respectively. For the removal of 25 mg L<sup>–1sup> phosphate in 1.0 mL aqueous medium, the commonly encountered anionic species in waters, e.g., Cl<sup>–sup>, SO<sub>4sub><sup>2–sup>, and NO<sub>3sub><sup>–sup>, pose no interfering effect at 8000 mg L<sup>–1sup>, providing a favorable removal efficiency of 100% by 2.0 mg of composite. When 142 mg L<sup>–1sup> phosphate solution is treated, 100% and >80% adsorption efficiencies are achieved respectively in the presence of 1000 and 8000 mg L<sup>–1sup> of Cl<sup>–sup>, SO<sub>4sub><sup>2–sup>, and NO<sub>3sub><sup>–sup>. The high tolerance capacity against coexisting anionic species by the graphene–La<sub>2sub>O<sub>3sub> composite makes it suitable for water cleanup by selective and fast adsorption/removal of phosphate.