In this work, we developed a facile one-step pyrolysis method for preparing porous ZnO/biochar nanocomposites (ZBCs) with a large surface area to enhance the removal efficiency of dye from aqueous solution. Peanut shells were pyrolyzed under oxygen-limited conditions with a molten salt ZnCl₂, which played the roles of the activating agent and precursor for the formation of nanoparticles. The effects of the mass ratio between the molten salt ZnCl₂ and peanut shells as well as pyrolysis temperature on the formation of ZBCs were investigated. Characterization results revealed that the as-synthesized ZBCs exhibited a highly porous structure with a specific surface area of 832.12 m²/g, suggesting a good adsorbent for efficient removal of methylene blue (MB). The maximum adsorption capacity of ZBCs on MB was 826.44 mg/g, which surpassed recently reported adsorbents. The formation mechanism of ZnO nanoparticles on the biochar surface was due to ZnCl₂ vaporization and reaction with water molecules extracted from the lignocellulosic structures. This study provides a basis for developing a simple and large-scale synthesis method for wastewater with a high adsorption capacity.

Magnetically separable core/shell Fe ₃ O ₄ /ZnO heteronanostructures (MSCSFZ) were synthesized by a facile approach, and their application for enhanced solar photodegradation of RhB was studied.

In this study, we provide a simple and green approach to recycle waste zinc carbon batteries for making carbon dots and porous carbon material. The carbon dots are easily synthesized by one green step, the hydrothermal treatment of a carbon rod in a mixture of DI water and pure ethanol to obtain a blue fluorescence under UV light, which can be used directly as a fluorescence ink. The as-prepared carbon dot process give typical dots with a uniform diameter from 3 to 8 nm with a strong slight blue fluorescent. The porous carbon material is also recycled from carbon powder in a waste battery via one green step annealing process without any chemical activation and with a hierarchically porous structure. This porous carbon material is demonstrated as an electrode for symmetrical solid state supercapacitors (SSCs) in a sandwich structure: porous carbon/PVA–KOH/porous carbon. The SSCs using recycled porous carbon electrodes exhibit a good energy density of 4.58 W h kg⁻¹ at a power density of 375 W kg⁻¹ and 97.6% retention after 2000 cycles. The facile one green step of hydrothermal and also that of calcination provide a promising strategy to recycle waste zinc carbon batteries, which transfers the excellent applications.

A magnetic recyclable biochar based photocatalysts was fabricated via a novel facile process which coupling ultrasonic-assisted impregnation and precipitation reaction, and its applicability for ciprofloxacin photodegradation was studied.