Evaluating the feasibility of chitosan-based carbon quantum dots in xerogel matrix for CO₂ removal

This study investigates the feasibility of using xerogel as a support matrix to stabilise chitosan-based carbon quantum dots (CCQDs) for CO₂ adsorption. After being hydrothermally treated for 24 hours at 180°C, CCQDs were immobilised in xerogel matrices with different ratios of CCQDs to solution. Tests for CO₂ adsorption were carried out at 30°C, 100 mL/min flow rate, and 5% CO₂ concentration. The CCQDX 1:50 sample had the maximum adsorption capacity, at 80.28 mg/g. The existence of hydroxyl, carbonyl, and C–O functional groups that promote CO₂ binding was verified by FTIR analysis. According to TGA measurements, CCQD-X 1:1 demonstrated exceptional thermal stability by retaining the largest residual mass of 40% at 950°C. With a surface area of 0.1864 m²/g for CCQD-X 1:50, BET analysis validated mesoporous properties, while FESEM pictures showed a heterogeneous xerogel surface shape. CHNS elemental analysis confirmed that nitrogen and sulfur were successfully incorporated, increasing the adsorbent's affinity for CO₂ through polar and basic surface functions. Overall, the results show that CCQDs supported by xerogel have better stability and functional characteristics, which makes them a viable and sustainable adsorbent for effective CO₂ collection applications.