Novel Polymer Sorbents with Imprinted Task-Specific Ionic Liquids for Metal Removal.

Kinga Filipowiak,Marek Nowicki,Aneta Lewandowska,Agnieszka Marcinkowska,Patrycja Dudzińska,Tomasz Buchwald,Karolina Wieszczycka

doi:10.3390/ma14175008

Abstract

In this paper, the potential of novel polymer sorbents with the imprinted IL-functional group for the removal of Cu(II), Cd(II), and Zn(II) from aqueous solutions was investigated by batch mode. The sorbents were fabricated by direct reaction of the prepared polymer matrix (poly(vinylbenzyl chloride-divinylbenzene), VBC, and poly(vinylbenzyl bromide-divinylbenzene), VBBr) with 1-(3- or 4-pyridyl)undecan-1-one and oxime of 1-(3- or 4-pyridyl)undecan-1-one. The Fourier Transform Infrared Spectroscopy (FT-IR), Raman Spectroscopy (Raman), Thermogravimetric Analysis (TG), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) techniques were used to show functionality and stability of the sorbents. The materials were also characterized by contact-angle goniometry, X-rayphotoelectron spectroscopy (XPS), and Zeta potential analysis. The removal of Cd(II), Cu(II), and Zn(II) was monitored and optimized under the influence of several operational controlling conditions and factors such as pH, shaking time, temperature, initial metal ions concentration, and counter-ions at the functional group. The results obtained confirmed the very high potential of the sorbents; however, the properties depend on the structure of the functional group. The tested sorbents showed fast kinetics, significant capacity at 25 °C (84 mg/g for the Zn(II) sorption with VBC-Ox4.10, 63 mg/g for the Cd(II) sorption with VBBr-Ox3.10, and 69 mg/g for the Cu(II) sorption with VBC-K3.10), and temperature dependence (even 100% increase in capacity values at 45 °C). The selected sorbent can be regenerated without a significant decrease in the metal removal efficiency.

Highlights

Heavy metals have a wide range of applications in various areas, such as medicine, technology, and the industry [1]
In the case of other materials, the results have shown no influence of the functional group structure on the sorption rate
Based on the conducted research, it was shown that the proposed procedure of the copolymer of vinylbenzyl chloride and divinylbenzene modification through quaternization in toluene as well as halogen exchange according the SN2 mechanism (poly(vinylbenzyl bromide-co-divinylbenzene) synthesis) enabled us to obtain novel ionic liquid-imprinted polymer sorbents

Summary

Introduction

Heavy metals have a wide range of applications in various areas, such as medicine, technology, and the industry [1] They are efficient catalysts because of their selectivity and their high activity [2]. Pollutants containing ions of heavy metals such as chromium, lead, copper, or cadmium are formed in chemical factories, batch production, mining, and metallurgy [3] They enter the ground water along with the wastewater from these industries. By incorporating organic functional groups onto the silica surface, there is an increase in uptake of metals and CO2, which improves the process efficiency [16,17,18,19,20], while a combination of polymers and ionic liquids can simultaneously remove both inorganic and organics pollutants from water [21]. The continuation of research, especially in the field of further modification of the functional group and selection of the counter-anion of the quaternary nitrogen in order to obtain novel efficient and stable sorbents, is justified

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