Development of Novel Hybrid Adsorbents of Strong Base Anion Exchange Resin and Inorganic Nanoparticles for Selective Removal of Phosphate and Arsenic from Water

Abstract

Development of selective adsorbents with an enhanced removal efficiency for the removal of phosphate and arsenic from water/wastewater is urgently needed to obtain safe water. Firstly, a hybrid adsorbent of nanoscale zirconium molybdate embedded within a macroporous anion exchange resin (ZMAE) was fabricated for selective removal of phosphate and arsenate. The ZMAE was characterized with low agglomeration of zirconium molybdate (ZM) NPs dispersed within the structure of the anion exchange resin (AE). As major results, the adsorption capacity of ZMAE for both phosphate and arsenate (26.1 mg-P/g and 46.7 mg-As/g, respectively) in the presence of excessive sulfate (5 mM) showed much superior to that of the pristine AE (1.8 mg-P/g and 6.9 mg-As/g, respectively) although their capacities were similar in the absence of sulfate. This selective performance of the ZMAE for both phosphate and arsenate in the presence of excess sulfate ion is attributed by the role of loaded ZM NPs which contributed to be more than 90% of the selective capacities of the ZMAE. Furthermore, the selective phosphate and arsenate of the ZMAE was confirmed by not only the batch experiment with synthetic model water/wastewater but also the column test. Secondly, this study proposed a new and effective method for fabricating a hydrated zirconium oxide NPs embedded anion exchange resin (ZAE) in purpose of development a robust and high selective adsorbent for phosphate removal. This proposed method achieved much more effective loading Zr within the resin than the conventional method. A series of the ZAE adsorbents with different Zr contents were fabricated and examined the selective adsorption of phosphate. As major results, the HZO NPs contributed to enhance both adsorption efficiency and selectivity of the anion exchange resin (AE). The selective adsorption of the ZAE for phosphate ion relied on the loaded HZO NPs and was in a function of the Zr content. Indeed, linear equation with high coefficient R2 value (R2  1.00) well described for the correlation between the Zr content and the maximum capacity of effective phosphate adsorption for either batch or column adsorption. These results allow to understand the selective insights of the ZAE toward phosphate ion. In overall, both hybrids ZMAE and ZAE promise a great potential for effective removal of phosphate and arsenic in real water/wastewater treatment. These could allow to explore a new route for synthesis of low cost and novel hybrid adsorbents for phosphate and arsenic.