Removal of Hydrogen Sulfide from the Sour Water of Tabriz Refinery Using Clinoptilolite Zeolite Adsorbent

Hydrogen sulfide (H2S) is a toxic, odorous, colorless, flammable and acidic gas. The main problems of hydrogen sulfide are the threat to health and safety, and causing corrosion and damage to metal installations. This study was conducted to remove hydrogen sulfide from the sour waters of Tabriz refinery and to recycle large amounts of water as well as to reduce air pollution in the refinery. In this experimental and laboratory study, the effect of pH, adsorbent content, initial concentration of pollutant, contact time and temperature on hydrogen sulfide removal process using clinoptilolite adsorbent was investigated. Thermodynamics, kinetics, and isotherms of adsorption process were studied. The results were used to remove H2S from the sour water of Tabriz refinery. The results showed that the optimal values of pH, absorbent value, initial pollutant concentration, contact time and temperature were 3, 1g/100 mL, 50 mg/L, 30 min and 25 oC, respectively. The results of thermodynamic studies showed that the adsorption process was exothermic, irreversible and spontaneous. The experimental data were better fitted to the pseudo-second order kinetics model and Freundlich isotherm model. After passing 100 ml of sour water from the fixed bed at 25 oC and 45 minutes, the removal efficiency was 96.7%. According to the results of this study, the proposed method due to its simplicity and high efficiency and the clinoptilolite due to its cheapness, abundance, ability to resuscitate and increase efficiency by enhancing the amount of clinoptilolite can be considered as an appropriate method and suitable adsorbent to remove hydrogen sulfide from the sour water of refineries and effluents.