Mathematical modeling of low-pressure H2S adsorption by babassu biochar in fixed bed column

The H2S removal by a microporous babassu-derived biochar (BBC) in fixed bed column under low pressure and temperature conditions was evaluated. For this, a mathematical model was coded to describe equilibrium and mass transfer kinetics in the column. The BBC showed desirable textural properties, namely, elevated external and micropore surface areas (584 m(2) g(-1) and 322 m(2) g(-1)) with super- and ultramicropores (7.8 angstrom and 5.8 angstrom) favoring the H2S diffusion. Also, various oxygenated groups provided high affinity for BBC-H2S system. The mathematical model was able to adequately describe the experimental data and to determine equilibrium (q(max) = 20.61 mg g(-1) and b = 16.84 L mg(-1)) and kinetic parameters (k(G) = 1.404 x 10(-2) to 2.378 x 10(-2) min(-1) and D-ax = 422.06 cm(2) min(-1)). Laminar flow (Re-p = 16.74) and small pressure drops were identified under the fluid dynamics conditions. Sensitivity analysis evidenced axial dispersion presents a minor effect over the bed performance, however for other flow conditions it should not be neglected. Also, the model showed predictive capacity, hence can support the adsorption systems design and scale-up. Overall, the BBC showed remarkable features for the H2S adsorption in fixed bed column, especially considering low-pressure and temperatures, since it allows straightforward infrastructure facilities.

Automated summary

This study evaluated the H2S removal by a microporous babassu-derived biochar in a fixed bed column under low pressure and temperature conditions. A mathematical model was developed to describe equilibrium and mass transfer kinetics, showing that the biochar displayed desirable textural properties and high affinity for the H2S system. The model had predictive capacity and could support the design and scale-up of adsorption systems.