KBH₄ enhances the electron transfer ability at the interface of biochar and accelerates the removal of ginsenoside Rb₁

Saponins are secondary metabolites produced during the growth of the medicinal plant Panax notoginseng. The accumulation of saponins in the soil alters the physicochemical properties and microbial community structure, leading to obstacles associated with continuous cropping. In this study, the surface structure of biochar was modified through KBH₄ treatment to enhance the elimination of ginsenoside Rb₁. It was found that the adsorption and degradation capacities of ginsenoside Rb₁ by biochar modified at 350 ℃ and 700 ℃ were 1.8 and 11.8 times higher respectively, compared to unmodified biochar. This enhancement is attribute to KBH₄ increasing the abundance of reducing functional groups (-NH₂/-OH) in biochar, thereby improving its electron transfer capacity and the hydrogen bonding interactions biochar and ginsenoside Rb₁. Additionally, compared to unmodified biochar, the cyclic voltammetric curve area and capacitance value of modified biochar were larger, while the radius of modified biochar was smaller in the middle and high frequency regions. These findings indicate that the increased electron transport rate of modified biochar can facilitate the degradation of ginsenoside Rb₁. The results of this study provide an effective solution to the challenges posed by soil continuous cropping obstacle caused by ginsenosides.