Carbon molecular sieves from coconut leaflets via chemical vapor deposition: Process optimization using box–behnken design

Pressure swing adsorption (PSA) represents one of the most advanced and versatile technologies for gas segregation and purification. The selection of an appropriate adsorbent is crucial in optimizing the PSA process’s efficiency. Biomass-derived carbon molecular sieves (CMSs) have emerged as a promising class of adsorbents, attracting considerable interest due to their carbon neutrality and cost-effectiveness. The present study explored the feasibility of utilizing coconut leaflets to synthesize CMSs through a chemical vapor deposition (CVD) technique. CMSs were produced from coconut leaflets by chemical activation using phosphoric acid (H₃PO₄) followed by chemical vapor deposition of benzene (C₆H₆). The effect of CVD process parameters, namely, deposition temperature (800–1000 °C), deposition time (15–45 min), and benzene flow rate (5–15 mL/min), on pore development of CMSs was investigated through Box–Behnken experimental design. The study found that deposition temperature, time, and flow rate of benzene strongly affect the pore structure of CMSs. Under the optimized conditions, deposition temperature of 888.972 °C, deposition time of 27.618 min, and benzene flow rate of 9.359 mL/min, the produced CMSs exhibited surface area of 1587.20 m²/g and micropore volume of 0.607 cm³/g which was 20.79 and 56.04% higher than coconut leaflet-derived activated carbon. CMSs were characterized for its textural, functional, morphological, and adsorption properties. The produced CMSs manifested a CO₂ adsorption potential of 287 mg/g. The study proved the feasibility of synthesizing an adsorbent material from coconut leaflets that can be utilized for gas separation and purification processes.