Use of nicotinamide decorated polymeric cryogels as heavy metal sweeper

Abstract

Cryogels are synthetic polymers used in adsorption experiments in recent years. Because of their macropores, they provide an excellent advantage as an adsorbent in continuous and batch adsorption processes. In this study, nicotinamide (NAA) decorated poly(2-hydroxyethyl methacrylate-glycidyl methacrylate), poly(HEMA-GMA), cryogels were synthesized. Heavy metal adsorption was carried out in wastewater obtained from six different sources in Çorum, Turkey. This study has a novelty regarding the application, i.e., it is the first time to use a polymeric adsorbent for the removal of 15 different heavy metal at the same time without any competition (despite the fact that there is a competition between the metals, the only thing is the removal regarding the purpose the study) as a heavy metal sweeper. Inductively coupled plasma-mass spectrometer (ICP-MS) was used for the determination of the initial amount of heavy metal in the wastewater samples. Adsorption studies were performed using poly(HEMA-GMA) and NAA-decorated poly(HEMA-GMA) cryogel to see the effect of NAA decoration. Higher adsorption capacity was achieved using NAA decorated poly(HEMA-GMA) cryogel. The total heavy metal amount adsorbed from six different sources was about 686 and 387 mg for poly(HEMA-GMA)-NAA and poly(HEMA-GMA) cryogels, respectively. The highest heavy metal adsorption value was obtained in the wastewater from source 2, and Zn (II) was the heavy metal adsorbed most for both cryogel. Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermal, surface area, elemental, and computerized microtomography (μCT) analyses were used for the characterization of cryogels.