High pyrolysis temperature biochar reduced the transport of petroleum degradation bacteria Corynebacterium uariabile HRJ4 in porous media

Biochar has been widely applied for the remediation of petroleum -contaminated soil. However, the effect of biochar on the transport of petroleum degradation bacteria has not been studied. A typical Gram-positive petroleum degradation bacteria-Corynebacterium uariabile HRJ4 was used to study the effect of different biochars on bacterial transport and retention. Results indicated that the addition of biochar in sand was effective for reducing the transport of bacteria and poplar sawdust biochar (PSBC) had a stronger hinder effect than corn straw biochar (CSBC). The hindrance was more evident with pyrolysis temperature of biochar raised from 300 degrees C to 600 degrees C, which was attributed to the increase of specific surface area (309 times). The hindrance effect also enhanced with higher application rate of biochar. Furthermore, the reduction of HRJ4 transport was more obvious in higher (25 mmo]/L) concentration of NaC1 solution owing to electrostatic attraction enhancement. The adsorption of biochar to HRJ4 was defined to contribute to the hindrance of HRJ4 transport mainly. Combining the influence of feedstocks and pyrolysis temperature on HRJ4 transport, it suggested that specific surface area had the greatest effect on HRJ4 transport, and pore -filling, electrostatic force also contributed to HRJ4 retained in quartz sand column. At last, phenol transportation experiment indicated that the restriction of biochar on HRJ4 enhanced the phenol removal rate in the column. This study provides a theoretical basis for the interaction of biochar and bacteria, which is vital for the remediation of oil -contaminated soil and groundwater in the field. (C) 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.

Automated summary

The addition of biochar in sand effectively reduces the transport of Gram-positive petroleum degradation bacteria, with different types of biochar and pyrolysis temperature showing varying hindrance effects. The hindrance of bacterial transport is more pronounced with higher application rates of biochar, especially in higher concentrations of NaCl solution.