In the present article, a two-step optimization strategy for the production of micro and meso- pores carbonaceous material has been proposed. The waste pistachio shell is utilized as precursor material to synthesize activated carbon on account of its high carbon and low ash content. The synthesization of pistachio shell-derived activated carbon (PSAC) includes carbonization and KOH-activation. The proposed mathematical modeling for the first step of optimization considers the effect of moisture content, the molecular mass of carbon and hydrogen constituents present in the carbonized samples, and the H/C ratio. The carbonized product is found to be best at the carbonization temperature of 562.5 °C based on the biochar throughput (TP) and percentage stable carbon content (%C_s). However, the second step of the optimization has been carried out on the basis of N₂ adsorption-desorption analysis and it recommends the best PSAC with the highest specific surface area of 703 m²/g with more than 55% of micropore volume. Further, the CO₂ capture assessment alongwith characterization is carried out, and PSAC2 is found to be the best adsorbent in terms of the highest amount of CO₂ capture.