Highly efficient removal of As(V) from aqueous solutions using a novel octanuclear Zn(II)-based polymer: Synthesis, structure, properties and optimization using a response surface methodology

Abstract

A novel octanuclear Zn(II)-based polymer, [Zn8(BTEC)2(ATZ)2(μ3-OH)2(μ2-OH)4 (H2O)2]n (1), was hydrothermally assembled using 5-amino-1-H-tetrazole (HATZ) with 1,2,4,5-benzenetetracarboxylic acid (H4BTEC). Complex 1 was characterized by single-crystal X-ray diffraction and TG. Owing to its unique characteristics, the ability of the [Zn8(BTEC)2(ATZ)2(μ3-OH)2(μ2-OH)4(H2O)2]n to remove As(V) from aqueous solutions was investigated (The form of As(V) is AsO43-). A series of experimental conditions of adsorption were studied, which included the pH value, contact time, adsorbent dose, adsorption temperature, initial concentration and shaking speed. The experimental results showed that complex 1 had a higher stable and relatively high (>98%) As(V) removal rate at pH 7–11. The adsorption process fitted well to the Langmuir model and the pseudo-second-order kinetic model. And the optimal adsorption conditions were also examined using a Box-Behnken design response surface methodology. In addition, complex 1 was further characterized by elemental analysis (CHN), photoluminescence(PL), XRD, IR spectroscopy before and after adsorption As (V).