DYNAMIC ADSORPTION OF H2S IN A FIXED BED OF SEWAGE SLUDGE PYROLYSIS CHAR

R. D. Possa, J. F. Sousa, J. A. Oliveira, P. F. P. Nascimento, M. T. A. Lima, I. B. Brandão, M. B. D. Bezerra

Abstract


In this work, sewage sludge char was tested as a H2S adsorbent in a fixed-bed column, at 25 °C. The char was activated physically and chemically (with HCl or KOH) to enhance textural properties. Commercial activated carbon impregnated with iron was also tested for comparison. The column was filled with 18.24 g of char and, then, fed H2S (600 ppm) under 50 mL/min. The effluent gas composition was measured via photocolorimetry and the data was used to plot breakthrough curves. A mathematical modeling was used to estimate parameters such as axial diffusivity, effective intraparticle diffusivity, and external mass transfer coefficient. The main results show that the adsorption capacities varied from 7.2 to 657.60 mgH2S/gads. The percentages of H2S adsorbed varied from 43.36 to 59.04%. HCl proved to be more efficient than KOH. Due to improved textural properties, the commercial activated carbon outperformed (69.15%, 12,527.80 mgH2S/gads) all char samples.

Keywords


H2S adsorption; sewage sludge pyrolysis char; breakthrough curve; mass transfer zone; fixed-bed column

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DOI: http://dx.doi.org/10.5419/bjpg2018-0008