Inhibition of microbiological sulfide oxidation by methanethiol and dimethyl polysulfides at natron-alkaline conditions

Abstract

To avoid problems related to the discharge of sulfidic spent caustics, a biotechnological process is developed for the treatment of gases containing both hydrogen sulfide and methanethiol. The process operates at natron-alkaline conditions (>1 mol L −1 of sodium-and potassium carbonates and a pH of 8.5-10) to enable the treatment of gases with a high partial CO 2 pressure. In the process, methanethiol reacts with biologically produced sulfur particles to form a complex mixture predominantly consisting of inorganic polysulfides, dimethyl disulfide (DMDS), and dimethyl trisulfide (DMTS). The effect of these organic sulfur compounds on the biological oxidation of sulfide to elemental sulfur was studied with natron-alkaliphilic bacteria belonging to the genus Thioalkalivibrio. Biological oxidation rates were reduced by 50% at 0.05 mM methanethiol, while for DMDS and DMTS, this was estimated to occur at 1.5 and 1.0 mM, respectively. The inhibiting effect of methanethiol on biological sulfide oxidation diminished due to its reaction with biologically produced sulfur particles. This reaction increases the feasibility of biotechnological treatment of gases containing both hydrogen sulfide and methanethiol at natron-alkaline conditions.

Development and validation of a physiologically based kinetic model for starting up and operation of the biological gas desulfurization process under haloalkaline conditions

“…All experiments were performed at 35 ˚C (DC10, Thermo Haake, Germany) which is in agreement with the conditions in the lab-scale fed-batch setup. As temperature and medium composition were similar to previous studies, a proper comparison of our results can be performed (De Graaff et al., 2012; Klok et al., 2013; Roman et al., 2015; Van Den Bosch et al., 2009).

Fig.

…”

Aerobic biodegradation of odorous dimethyl disulfide in aqueous medium by isolated Bacillus cereus GIGAN2 and identification of transformation intermediates

“…Otherwise, in route II, dimethyl trisulfide was detected, which might be derived from intermolecular interaction of DMDS. Similar route could also be found in some previous studies (Chin and Lindsay, 1994;van den Bosch et al, 2009). Meanwhile, according to the kinetics results, both routes can lead to the mineralization of DMDS into CO 2 , H 2 O and sulfate after a series of degradation steps (Wei et al, 2013).…”

Influence of methanethiol on biological sulphide oxidation in gas treatment system

“…Instead, we detected accumulation in the bioreactor suspension up to a total concentration of ∼16 µM S at −450 mV (Figure 3(a)). Van den Bosch et al [27] studied the inhibitory effect of DMDS and DMTS on the bacterial oxidation of sulphide and found that DMTS is more toxic to SOB than DMDS. Besides dimethyl polysulphanes, also inorganic polysulphide anions were produced from the reaction between methanethiol and elemental sulphur (Equation (6)), as reflected by the somewhat higher S 2−…”