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Hydrous lanthanum oxide was loaded onto the surface of Fe 3 O 4 @SiO 2 core/shell magnetic nanoparticles to obtain an easily separable adsorbent (abbreviated as Fe–Si–La) for efficient separation of phosphate from water. Fe–Si–La was characterized with XRF, XRD, TEM, specific surface area and magnetization and their performance for phosphate removal was investigated. The Fe 3 O 4 @SiO 2 core/shell structure was confirmed and the hydrous lanthanum oxide was successfully loaded onto its surface. The newly developed adsorbent had magnetization of 51.27 emu/g. The Langmuir adsorption capacity of phosphate by Fe–Si–La reached 27.8 mg/g by loading only 1 mmol lanthanum per gram of magnetite. The adsorption was fast; nearly 99% of phosphate could be removed within 10 min. The removal of phosphate was favored within the pH range 5.0–9.0. The adsorption on Fe–Si–La was not significantly influenced by ionic strength and by the coexistence of the anions of chloride and nitrate but sulfate, bicarbonate and humic acid showed slightly greater negative effects. Phosphate removal efficiency of higher than 95% was attained for real effluent of a wastewater treatment plant when the dose of adsorbent was >0.2 kg/ton. The results showed that adsorbed phosphate could be nearly completely desorbed with NaOH solution for further use. In conclusion, Fe–Si–La is a promising adsorbent for the removal and recovery of phosphate from water. [ABSTRACT FROM AUTHOR]

Abstract: With the goal to develop a coal fly ash-based versatile material toward a broad range of pollutants in water, a zeolite (ZFA) was synthesized from coal fly ash and subsequently modified by chitosan. The chitosan modified zeolite (CMZFA) was examined for its capability to sequester cationic (ammonium), anionic (phosphate) and organic (humic acid) pollutants from water. The cation exchange capacity in the internal pores was regarded as the retention capability for cationic ammonium. From the difference between the total and external cation exchange capacity, it was estimated to be 0.90mmol/g (16.2mg/g). Results showed an improved adsorption of CMZFA for phosphate when compared with ZFA, and a maximum adsorption capacity of 4.05mg/g was obtained for CMZFA from the Langmuir model. Though ZFA presented little affinity for humic acid, modification by chitosan largely enhanced the adsorption performance with a Langmuir maximum of 31.6mg/g. The negative charge in the internal pores of zeolite, the oxides of CaO, Al2O3 and Fe2O3 in the non-zeolite fraction, and the monolayer chitosan on the external surface of zeolite were interpreted as the binding bodies for the retention of cationic ammonium, anionic phosphate, and organic humic acid, respectively. [Copyright &y& Elsevier]

[Display omitted] • A macroporous MF-HA was prepared via a facile adsorbing method for phosphate removal. • MF-HA could effectively adsorb phosphate over a wide pH range with high selectivity. • Phosphate of 3 mg P/L could be reduced to 0.0015 mg/L. • MF-HA could be easily separated after adsorption with good recyclability. • The cost-efficient raw materials and simple engineering improved its practicality. Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4–10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas. [ABSTRACT FROM AUTHOR]

[Display omitted] • A macroporous MF-HA was prepared via a facile adsorbing method for phosphate removal. • MF-HA could effectively adsorb phosphate over a wide pH range with high selectivity. • Phosphate of 3 mg P/L could be reduced to 0.0015 mg/L. • MF-HA could be easily separated after adsorption with good recyclability. • The cost-efficient raw materials and simple engineering improved its practicality. Effective removal of phosphate from aqueous solution is of great significance in environmental protection. In this paper, the concept of developing a hierarchical and cost-effective aluminum functionalized melamine foam (MF) as phosphate adsorbent is presented. The material with 3D interconnected network, flexibility and ultralow density was fabricated via a simple adsorbing method based on hydrate aluminum and commercially available MF sponge. For use as an adsorbent, performance of the as-prepared MF-HA sponge was assessed with various pH, temperatures, adsorption time, initial P concentrations, ionic strengths and co-existing ions. The experimental results demonstrated that MF-HA performed well in a wide pH range of 4–10 and in the presence of foreign anions, with high maximum uptake capacity of 36.21 mg P/g. Furthermore, for the as-prepared material, the phosphate removal performance at different temperatures established the endothermic nature of the adsorption process. Moreover, MF-HA sponge could be directly separated from the solution and showed a satisfactory recyclability. The adsorbing strategy to design and fabricate the novel sponge with resultant high adsorption efficiency, cost-effectiveness, preferable selectivity, environmental friendliness, and easy separation from water may promote sponge functionalization for applications in extensive wastewater treatment areas. [ABSTRACT FROM AUTHOR]