Stepwise Synthesis of Mesoporous Carbon Nitride Functionalized by Melamine Based Dendrimer Amines for Adsorption of CO2 and CH4

Abstract

In this study, a novel solid dendrimer amine (hyperbranched polymers) was prepared using mesoporous carbon nitride functionalized by melamine based dendrimer amines. This adsorbent was denoted MDA-MCN-1. The process was stepwise synthesis and hard-templating method using mesoporous silica SBA-15 as a template. Cyanuric chloride and N,N-diisopropylethylamine (DIPEA, Merck) were used for functionalization of the MCN-1. Fourier transform infrared spectroscopy (FT-IR), Nitrogen adsorption-desorption analysis, Small Angle X-ray Scattering (SAXS), X-ray diffraction (XRD) and thermogravimetric analysis (TGA) were used for characterization of the adsorbent. This material was used for carbon dioxide gas (CO₂) and methane gas (CH₄) adsorption at high pressure (up to 20 bar) and room temperature. The volumetric method was used for the tests of the gas adsorption. The CO₂ adsorption capacity of modified mesoporous carbon nitrides was about 4 mmol CO₂ per g adsorbent. The methane adsorption capacity of this material was less than that CO₂. Modified Mesoporous Carbon Nitride adsorbed about 3.52 mmol CH₄ /g adsorbent. The increment of melamine based dendrimer generation on mesoporous surface increased adsorption capacity of both carbon dioxide and methane gases. According to the results obtained, the solid dendrimer amines, (MDA-MCN-1), performs excellently for CO₂ and CH₄ capture from flow gases and CO₂ and CH₄ storage.