Efficient removal of cesium ions using Prussian blue loaded on magnetic porous biochar synthesized by one-step calcination.

Prussian blue (PB) is widely used for the selective removal of radioactive cesium ions (Cs+) from aqueous solutions. Due to its small size and easy dispersion in water, PB requires a carrier that is both inexpensive and easily separable. Magnetic porous biochar (MPBC) was formed by activating starch with FeCl3 through a one-step calcination method. MPBC can be used as a carrier for Prussian blue, which is easily separated from the solution. This composite material (PB/MPBC) has a rich pore structure and maintains effective surface area, which can facilitate the penetration of Cs+ into the adsorbent. Besides, PB/MPBC exhibits high selectivity and good adsorption capacity achieving a large removal capacity of 101.43 mg/g. Thus, this study provides a novel approach for preparing composites with efficient removal of Cs+.

Enhanced adsorption capacity of tetracycline on porous graphitic biochar with an ultra-large surface area.

Excessive tetracycline in the water environment may lead to the harming of human and ecosystem health. Removing tetracycline antibiotics from aqueous solution is currently a most urgent issue. Porous graphitic biochar with an ultra-large surface area was successfully prepared by a one-step method. The effects of activation temperature, activation time, and activator dosage on the structural changes of biochar were investigated by scanning electron microscopy, Brunauer-Emmett-Teller, X-ray powder diffraction, and Raman spectroscopy. The effect of the structure change, adsorption time, temperature, initial pH, and co-existing ions on the tetracycline removal efficiency was also investigated. The results show that temperature had the most potent effect on the specific surface area, pore structure, and extent of graphitization. The ultra-large surface area and pore structure of biochar are critical to the removal of tetracycline. The q e of porous graphitic biochar could reach 1122.2 mg g-1 at room temperature. The calculations of density functional theory indicate that π-π stacking interaction and p-π stacking interaction can enhance the tetracycline adsorption on the ultra-large surface area of graphitic biochar.