Size effect of mesoscopic‐scale silver particles on the adsorption capacity of silver/cotton for fuel oil desulphurization

Abstract

Thiophene and its derivatives in fuel oils, such as diesel, will be converted into SO x pollutants after combustion. Cotton is an inexpensive, sustainable biomass and a promising candidate for adsorbent supports because of its quasi-one-dimensional structure. Hence, we prepared silver/cotton adsorbents with silver loadings of 0.2, 0.8, and 4.3 wt% through a simple wet reduction method. Field emission scanning electron microscopy (FESEM) results show that when the silver loading was as high as 4.3 wt%, large silver aggregates were obtained; when the silver loading was as low as 0.2 wt%, small silver particles with diameters of $0.1 mm (mesoscopic scale) were primarily prepared. Static adsorption results demonstrated that the large silver aggregates were ineffective for the adsorption of thiophene, while the small silver particles showed an exceptional adsorption performance. At 30 8C, the highest thiophene adsorption capacity reached 10 mg/g on the 0.2 wt% silver/cotton adsorbent. The adsorption isotherm of the 0.2 wt% silver/cotton adsorbent was determined and exhibited a multi-step trend. In addition, the bed pressure drop of the 0.2 wt% silver/cotton was determined to be 0.62 kPa/g, which was 26.0 % and 16.7 % of those of alumina and silica gel, respectively.