An ion-imprinted imidazole-functionalized ordered mesoporous silica for selective removal of chromium(VI) from electroplating effluents.

Shuibin Cen,Jiean Tan,Lan Yang,Shengzhao Gong,Ruimin Li,Lixi Zeng

doi:10.1007/s11356-022-19209-8

Abstract

In this work, ion imprinted technology incorporated with mesoporous silica materials (MCM-41) to obtain the novel specific adsorbent, ion imprinted mesoporous silica. Cr(VI) imprinted mesoporous silica (Cr(VI)IMS) was synthesized and used for adsorption studies and waste water application. A synthesized imidazolyl silane agent act as the functional monomer in the imprinted process to build up highly ordered functionalized imprinted materials. The chemical composition, porosity, and highly ordered morphology were characterized by Fourier transform infrared spectroscopy (FTIR), solid state nuclear magnetic resonance (NMR), Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), transmission electron microscopy (TEM), and scanning electron microscopy (SEM), respectively. The Brunauer-Emmett-Teller (BET) surface area was 1054.51 m2g-1 in this study. The Cr(VI)IMS showed great adsorption capacity to hexavalent chromium ions in acidic solution up to 45.6mgg-1. Cr(VI)IMS reached the adsorption equilibrium in a short time (10min) at acid and weak acid conditions, while most of adsorbents need more than 30min to achieve adsorption equilibrium. Cr(VI)IMS displayed much higher adsorption capacity to Cr(VI) ions than other negative ions. The relative selectivity coefficient was 2.56, higher than those of other anions (below 1.5). After eight adsorption-regeneration cycles, the adsorption efficiency of Cr(VI)IMS still reached 92.5%. The Cr(VI)IMS was found to exhibit equivalent property after multiple cycles of experiments, indicating good repeatability and reproducibility.

Highlights

Chromium is widely used in various industries, such as plating, tanning, paint and pigment production and metallurgy, which could possibly contaminate the environmental waters if it is not treated standardly (Gómez and Callao 2006)
The chemical composition, thermal stability, porosity and highly ordered morphology were characterized by Fourier transform infrared spectroscopy (FTIR), solid state nuclear magnetic resonance(NMR), Brunauer-Emmett-Teller (BET) method, X-ray diffraction (XRD), transmission electron microscopy (TEM) and scanning electron microscopy (SEM) respectively
We developed Cr(VI) imprinted mesoporous silica synthesis method which combined the advantages between mesoporous material with ion imprinted technology

Summary

Introduction

Chromium is widely used in various industries, such as plating, tanning, paint and pigment production and metallurgy, which could possibly contaminate the environmental waters if it is not treated standardly (Gómez and Callao 2006). It is well known that the toxicological and biological properties of most elements depend upon their chemical forms. Chromium element in waste water is mainly existed as Cr(III) and Cr(VI). Strong oxidizing Cr(VI) can penetrate biological membrane and cause cancer or other diseases. Cr(III) can be precipitated at high pH (Petruzzelli et al 1995), while Cr(VI) ions are highly soluble at different pHs (Li et al 2013) and can be transported over a great distance existing in a variety of oxo-species, namely, dichromate (Cr2O72−), hydrochromate (HCrO4−) or chromate (CrO42−), which threatens environment and creature health. It is indispensable to develop efficient method to cope this problem

Methods

Results

Conclusion