Palladium nanoparticles produced by Caldicellulosiruptor saccharolyticus with dissolved hydrogen enhanced the degradation of contaminant in water

摘要

This study focused on examining the general applicability of coupling bio-Pd nanoparticle generation and bio-H_2 produced by C. saccharolyticus for water treatment under extreme-thermophilic conditions. Palladium was added to cell cultures to achieve a final Pd concentration of 50 mg/L. Methyl orange and diatrizoate were chosen as the contaminants in water. MO (100 mg/L) was degraded within 30 min in the cultures with Pd added, while 6 hours were needed without Pd addition. Diatrizoate (20 mg/L) was degraded within 10 min in Pd added cultures. However, diatrizoate was not degraded in the culture without Pd. The degradation rates were positively correlated with dissolved hydrogen generated by C. saccharolyticus. Furthermore, the catalytic actions of Pd(0) nanoparticle and cell were distinguished during the degradation process. Dissolved hydrogen produced by C. saccharolyticus should be the perfect reduction equivalent for Pd formation. Thus the biodegradation proceeding with the action of in situ bio-H_2 in natural environment of high temperature should be illuminated. And cells of C. saccharolyticus dispersed the Pd(0) particles well and showed a better catalytic activity than chemic-Pd(0) without dispersant. Generally speaking, Pd addition would be an optimal choice to enhance the degradation of contaminant in water.