Activated Carbon Spheres for CO₂ Adsorption

A series of carbon spheres (CS) was prepared by carbonization of phenolic resin spheres obtained by the one-pot modified Stöber method. Activated CS (ACS), having diameters from 200 to 420 nm, high surface area (from 730 to 2930 m²/g), narrow micropores (<1 nm) and, importantly, high volume of these micropores (from 0.28 to 1.12 cm³/g), were obtained by CO₂ activation of the aforementioned CS. The remarkably high CO₂ adsorption capacities, 4.55 and 8.05 mmol/g, were measured on these AC spheres at 1 bar and two temperatures, 25 and 0 °C, respectively

Cysteine-Assisted Tailoring of Adsorption Properties and Particle Size of Polymer and Carbon Spheres

A series of cysteine-stabilized phenolic resin-based polymer and carbon spheres were prepared by the modified Stöber method. Cysteine plays a very important role in the proposed one-pot synthesis of the aforementioned spheres; namely, it acts as a particle stabilizer and a source of heteroatoms (nitrogen and sulfur) that can be introduced into these spheres. The diameter of these spheres can be tuned in the range of 70–610 nm by adjusting the cysteine amount and reaction temperature. Since polymer spheres obtained in the presence of cysteine contain sulfur and nitrogen heteroatoms, they were tested for adsorption of copper ions. It is shown that adsorption isotherms recorded for copper ions can be well fitted by Langmuir equation, giving unprecedented adsorption capacities up to ∼65 mg/g