Experimental

Three different commercial activated carbons were used in this study: CNR (CNR 115, phosphoric acid activated carbon, from Norit), 208 (208C, steam activated carbon, from Chemviron) and R2 (R2030, steam activated carbon, from Norit).

Activated carbons were characterized by nitrogen adsorption at 77 K and temperature-programmed decomposition (TPD) experiments, as described elsewhere.10 N2 adsorption experiments were used to determine the porous structure while TPD experiments were used to characterize the surface chemistry (oxygen surface groups).

Propanethiol removal kinetic experiments were carried out at room temperature and atmospheric pressure.10 The propanethiol solution (10 mL; [Co]:168 ppmw S in «-hexene) containing the activated carbon sorbent (200 mg) was periodically analyzed using a gas chromatograph (Varian GC 3800) equipped with flame ionization (FID) and pulsed flame photometric (PFPD) detectors.

Fixed-bed adsorption/breakthrough tests were performed in a continuous flow packed glass bed reactor (1 cm i.d., 17 cm length). Initially, 2 g of the corresponding activated carbon (particle size 0.5 < * < 0.7 mm) were packed into the glass column and heated in a He flow (50 mL min-1) at 473 K during 4 h, in order to remove surface impurities. After cooling down to room temperature, the He gas was switched to a sulfur free hydrocarbon effluent («-pentane) until the activated carbon was completely wet. After wetting the carbon for 30 min, the feed was switch to the «-hexene/ propanethiol mixture (420 ppmw S) at 0.5 mL min-1. Once «-hexene starts to leave the column, effluent samples were collected at regular intervals following the reaction products by GC, as described above.

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