Synthesis and characterization of waste Styrofoam hypercrosslinked polymer as an adsorbent for CO2 capture

In this work, we used waste Styrofoam as a precursor to synthesize a hypercrosslinked polymeric (HCP) adsorbent for CO2 adsorption utilizing the Friedel-Craft procedure. The hypercrosslinked adsorbent was designed using formaldehyde dimethyl acetal (FDA) as the crosslinker. The precursor to crosslinker to catalyst ratio was 1:3:3, and the HCP synthesis was carried out for 12 h at 312.6 K. Fourier-transform infrared spectroscopy, field emission scanning electron microscopy, and thermogravimetric analysis were used to analyze the waste Styrofoam hypercrosslinked (WSHC) adsorbent. The adsorbent attained an 802.84 m(2)/g Brunauer-Emmett-Teller (BET) surface area and an average pore diameter of 2.869 m(3)/g. The CO2 adsorption process was studied under different operating conditions, temperature between 298 and 328 K and pressure between 2 and 10 bar. WSHC adsorbent has the maximum CO2 uptake with a value of 11.053 mmol/g at 298 K and 10 bar. The behavior of the adsorption process was investigated using isotherm, kinetic, and thermodynamic models. Experimental findings indicated that the Sips isotherm and the second-order kinetic models provided the best fit. The isotherm data indicated that adsorption occurs in multi-layers and is heterogeneous. According to the thermodynamic characteristics, the process is exothermic and spontaneous. Finally, the kinetic findings established that the process happened physically. Additionally, a regeneration study after seven cycles revealed a 96.1% success rate. The current research may attempt to use waste Styrofoam as a gas separation adsorbent in the industry.