The control of carbon dioxide emissions using porous adsorbents has received significant attention from researchers. In this regard, graphene aerogel, due to its porous structure consisting of macro/meso/micro pores an‎d controllable chemical structural, exhibits a high capacity for CO2 gas adsorption. However, textiles used for CO2 gas adsorbing in other research studies are often based on glass an‎d carbon fibers, which usually require complex physical an‎d chemical modifications to improve CO2 gas adsorption efficiency. Thus, the objective of this research is to develop a novel CO2 gas adsorbing fibrous structure by coating graphene aerogel nanostructures onto PET fabric. In this context, the self-assembly process an‎d the formation of macro/meso/micro porous structures, along with the chemical modification of graphene aerogel to enhance the CO2 gas adsorption capacity, were achieved through process variable control. Subsequently, a suitable method for coating graphene aerogel nanostructures onto fibrous structures, focusing on controlling electrostatic interactions between the fibrous structure an‎d graphene sheets, was investigated. The goal in this section was to analyze the self-assembly process of graphene sheets an‎d simultaneously create aerogel structures to form a uniform an‎d stable coating on the textile surface. The self-assembly of graphene oxide sheets was initially controlled by optimizing the oxidation levels of oxygen groups in graphite. Process variables for synthesizing graphene oxide (potassium permanganate, sulfuric acid, hydrogen peroxide) were examined. The formation of optimal macro/meso/micro porous graphene aerogel structures was studied through controlling electrostatic, π-π, van der Waals, an‎d hydrogen interactions, an‎d chemical modifications were made to increase CO2 adsorption efficiency. CO2 adsorption by synthesized aerogel using high sulfuric acid concentrations during graphene oxide synthesis was measured at 1.72 mmol/g, an‎d after chemical modification of graphene aerogel with monoethanolamine, CO2 adsorption capacity showed a threefold increase. Optimal hydrothermal synthesis conditions for aerogel formation were determined to be a duration of 10 hours an‎d 140°C, resulting in aerogel with the highest meso an‎d micro surface areas (152 m²/g an‎d 169 m²/g). Based on XPS results, increasing the amine group content an‎d NH/NT ratio to 0.35 increased CO2 adsorption to 5.1 mmol/g. The Elovich kinetic model showed a good agreement with experimental data, confirming simultaneous physical an‎d chemical adsorption of CO2 on graphene aerogel. Further eva‎luation revealed that macro/meso/micro pore sizes significantly affected Elovich model coefficients, indicating initial diffusion rates an‎d surface barrier CO2 diffusion. The intraparticle diffusion model was identified as the rate-limiting model for controlling CO2 diffusion in aerogels. Increasing the graphene oxide concentration reduced the rate-limiting constant in this model compared to samples synthesized at varying hydrothermal synthesis times, due to reduced macropores in the aerogel. Further research involved coating graphene aerogel onto polyester fabric using in-situ synthesis under various hydrothermal conditions. Hydrothermal conditions were optimized to prevent textile degradation during coating an‎d control interactions between graphene oxide sheets an‎d polyester fabric. To enhance chemical CO2 adsorption by coated fabric, amine modification using polyethyleneimine (PEI) through various approaches was investigated. Results showed that pre-modifying PET with PEI followed by in-situ synthesis coating significantly improved the self-assembly of graphene oxide sheets, forming a uniform an‎d stable porous graphene coating. This method enhanced CO2 adsorption of the resulting textile by approximately four times compared to untreated polyester samples.

زهرا طالبي مزرعه شاهي , وحيد غفاري نيا

اكبر خدامي , عليرضا نجفي چرمهيني , مصطفي يوسفي , احمدرضا بهراميان