Iranian Journal of Chemical Engineering (IJChE)

Abstract The removal of hydrogen sulfide (H₂S) from airstreams was studied in a biotrickling filter packed with porous lava as a carrier of Thiobacillus thioparus (DSM5368) with counter current flows of the air and liquid streams. The effect of operating parameters on biotrickling filter performance was studied. Experiments were performed at different empty bed residence times (9-60 sec), and moderate H₂S concentrations (10-90 ppm) to assess the performance of biotrickling filter at different conditions of these parameters. The effect of superficial liquid velocity (0.98-1.95mh^-1) on the performance of biotrickling filter was evaluated. Increasing superficial liquid velocity decreased removal efficiency of the BTF. The gradual change in the concentration of H₂S in different heights of the BTF was investigated. Decreasing empty bed residence time lead to a slight increase in the homogeneity of the removal at different heights of the BTF; however the effect of change in the inlet concentration was insignificant. Complete removal was achieved in the first 85% of the bed. To gain a brief insight into the robustness of the biotrickling filter, its performance was investigated after several upsets in the system.
 
 

Abstract Lennard-Jones-Devonshire equation of state is an old but theoretical based EOS. The concept of the nearest neighboring molecules or coordination number is proposed to be a function of temperature and volume, whereas it is a constant in the original. The dilute gas and hard sphere limits of molecules are employed to determine this function. Improvement of this modification is demonstrated by property calculations for Lennard-Jones fluid. Results of the modified LJD equation of state offer senior accord with simulation data of Lennard-Jones fluid than those of the original version.    

Abstract > In this paper a chemical method applied to synthesize exfoliated graphite (EG) is presented. In this method graphite intercalation compound (GIC) was firstly synthesized by chemical treatment of graphite flakes using a mixture of sulfuric and nitric acids followed by thermal shock of GIC at 1000°C to produce EG. The bulk density of synthesized EG was found to be as low as 4.5 kg/m3. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques were used for identification and characterization of different materials. According to the XRD observations, the GIC was identified as graphite bisulfate with stage 2, and residue GIC and EG had nearly the same diffraction pattern, but with distinctly lower intensity. In accordance with SEM results the residue graphite bisulfate was swelled in comparison with the graphite flake. The oil sorption capacity of synthesized EG in this work was studied by common static and dynamic tests and compared with other sorbents. The results show the superior capability of EG for oil spill cleanup.