Isolation, optimization and effect of organic sodium-removing bacterium from coal

Abstract:

[Background] The alkali metal sodium affects coal burning equipment and gasification efficiency in the coal combustion process and acid wastewater is produced in the pickling process. [Objective] To propose a novel method for removing organic sodium from coal by microorganisms. [Methods] A bacterial strain, which was isolated and screened out from Huangqihai, Chahar Right Front Banner, Ulanqab, Inner Mongolia, was identified based on morphological, physiological, and biochemical characteristics and the 16S rRNA gene sequence, and a phylogenetic tree was constructed. The optimal growth conditions of the strain were investigated by single factor tests, and the growth curve was plotted. The optimal removal conditions of organic sodium in coal by the strain were determined, and the removal effect was evaluated under the optimal conditions. [Results] A strain that can remove organic sodium from coal was screened out and identified as Sphingomonas aquatilis. The strain showed the best growth performance in the medium with glucose (4 g/L) as the carbon source, peptone (13 g/L) as the nitrogen source, and initial pH 8.0 when it was cultured at 30℃ and 150 r/min with the inoculum quantity of 3% and liquid loading of 100 mL. The optimal removal conditions of organic sodium from coal were as follows:initial pH 8.0, liquid loading of 80 mL, coal slurry concentration of 5 g/L, and inoculum quantity of 7%. Under the conditions, the removal efficiency of organic sodium from coal by strain CSW-1 was 23.79%. [Conclusion] A novel method for removing organic sodium from coal by microorganisms is proposed for the first time, which provides a new idea for the efficient and clean utilization of coal.

Key words:coal;organic sodium;Sphingomonas aquatilis;screening;removal efficiency