Green synthesis of functional biochar derived from sediment/blue algae/rectorite and the enhanced interaction of DNA in the aquatic environments: a mechanistic study

Most recently, the whole globe is faced with crisis such as the energy crisis, ecological pollution. The escalation and spread of antibiotic resistance genes (ARGs) are becoming emerging pollutants due to the abuse of antibiotics, posing serious damage to human health and ecology. The transformation of extracellular DNA, which is the genetic material, tends to be adsorbed by ubiquitous porous materials other than being in freedom, to block the transmission and diffusion of free DNA in the environment and to achieve the resource reuse of waste pollutants. Herein, composite biochar (RSA) derived from natural lake sediment, blue algae, and 1:1 type clay, Fe-pillared rectorite was successfully prepared by facial one-pot hydrothermal strategy. The composite RSA was taken as functional photocatalyst for DNA adsorption/degradation. The morphologies, structural properties of the as-prepared composites were investigated via SEM, BET, pHpzc, FT-IR, TG, and XRD techniques. The adsorption capacity of DNA by RSA (11.78 µg/mg) was enhanced. Accordingly, DNA adsorption on RSA was mainly dominated by chemical interactions, which was preferable in acidic and low-salt environment. The ROS detection and quenching experiments gave proof that 1 O 2 generated by RSA was responsible for the light-induced cleavage of DNA into fragments. XPS analysis revealed the interaction between Lewis acid bond P–O in DNA and Lewis base bond Al–OH in RSA. This study will advance our fundamental perspectives for the green remediation of extracellular DNA by using biochar derived from natural resource. Graphical abstract