Amine-bearing electrospun nanfibrous adsorbent using radiation induced grafting for carbon dioxide capturing

Abstract

Carbon dioxide (CO2) is the most polluting greenhouse gas released into the atmosphere in large quantities causing global warming. Immobilization of amine groups containing compounds on a solid substrate is a straightforward approach for CO2 adsorption. The main aim of this study is to prepare new amine-containing adsorbents having nanofibrous structures for efficient capturing of CO2 from different environments. The adsorbent preparation involved i) electrospinning of syndiotactic polypropylene (s-PP) solution, ii) radiation induced graft copolymerization of glycidyl methacrylate (GMA) onto the electrospun nanofibers, and iii) functionalization of poly-GMA grafted s-PP nanofibrous mats with different amines (ethanolamine, diethylamine and triethylamine). The effect of various electrospinning parameters such as voltage, needle tip to collector distance and flow rate on the morphological properties of the produced nanofibers was studied using the response surface method (RSM). The effects of grafting parameters such as absorbed dose, monomer concentration, time and temperature on the degree of grafting (DG) were also investigated. The Scanning electron microscopy (SEM), Fourier transform infra-red (FTIR), Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA) and Brunauer-Emmet-Teller (BET) techniques were used to determine morphological, chemical, thermal properties and stability, changes in the structure of the nanofibers after each modification step. Finally, the amine-bearing nanofibers were tested for CO2 adsorption in a fixed bed column under different operating parameters such as DG in adsorbent, amine type, initial CO2 concentration and temperature. The highest CO2 adsorption capacity of 2.87 mmol CO2/g was achieved in an adsorbent having 300 % DG and functionalized with ethanolamine at 15 % initial CO2 concentration, atmospheric pressure and 30 °C. This study showed that new class of CO2 adsorbents can be successfully prepared by combining electrospinning with radiation induced grafting techniques followed by amine loading.