A rapid one-pot microwave-assisted strategy toward the synchronous preparation of two nano-biomaterials with different scales: lignin nanoparticles and carbon nanodots.

The conversion of low-cost renewable lignin could enable the economic fabrication of carbon materials for energy storage devices. However, the traditional activation methods for the production of a lignin-derived porous carbon with a large specific surface area are complex and expensive, and some activators can cause pollution. In this paper, we propose a novel green bacterial activation method for the synthesis of a carbon material with a large surface area of up to 1831 m² g⁻¹ and abundant micropores and mesopores through a conventional carbonization procedure with a simple bacterial culture process. The transformation of the lignin structure by the bacteria optimizes the pore structure of the derived carbon and promotes graphitization. Consequently, as an electrode in a supercapacitor, the obtained material exhibits a very high specific capacitance (428 F g⁻¹ at 1 A g⁻¹), high cycling stability (capacitance retention of 96.7% after 10 000 cycles at 5 A g⁻¹), and superior rate performance in an aqueous electrolyte. In addition, the symmetric supercapacitor based on the bacteria-activated lignin-derived carbon exhibits a superior energy density of 66.18 W h kg⁻¹ at 312 W kg⁻¹ in an ionic liquid electrolyte system. These excellent features demonstrate the large potential of the developed material for applications in high-performance supercapacitors. Furthermore, the proposed bacteria-activation method can guide a novel bio-modification for material syntheses.

Excessive levels of heavy metal(loid)s (HMs) in natural environments pose a serious threat to living beings worldwide. HM exposure causes irreversible damage to structural components and metabolic processes in living organisms, as has been observed in multiple studies on various organisms. In the natural environment, biological individuals interact with others through the food web rather than exist independently, which facilitates the transfer of HMs in the food web. However, the difference in HM toxicity among different biological species has not been elucidated. This review provides information on the speciation and migration of HMs in different environments to clarify the HM exposure routes of different biological species. The differences in the biotoxicity of HMs to different species, from microbes to humans, are emphasized. The relationship between HM toxicity and biological species is confirmed by the fact that HMs can be transferred and bioaccumulated along the food chain. Effective strategies for decreasing HMs emissions and removing HMs from the environment are briefly discussed. Finally, the limitations of the present study and future perspectives are discussed.