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Bacterial infections, the toxicity of engineered nanomaterials, the presence of inorganic pollutants in the environment, and providing safe drinking water are the most threatening problems of the 21st century. To tackle these challenges, we develop a one-pot, solvent free, and rapid synthesis of smart magnetic graphene (SMG) by microwave irradiation of graphene oxide (GO) and ferrocene precursors. The SMG possesses increased adsorption sites with tunable superparamagnetic properties (50 emu/g, 1:7 wt %), facilitating the adsorption and magnetic separation of aqueous Cr(VI), As(V), and Pb(II) with ∼99% removal efficiencies down to the 1 ppb level. The X-ray photoelectron spectroscopy (XPS) analysis of SMG-Cr(VI) reveals the reduction of Cr(VI) to Cr(III), presumably due to the surface phenolic groups and unprotected ferrous ions on the SMG surface. The maximum adsorption capacity of SMG is 4.86, 3.26, and 6.00 mg/g for respectively Cr(VI), As(V), and Pb(II) at an initial concentration of 5.0 ppm. The addition of KNO3 does not affect Cr(VI) adsorption efficiency; whereas Na2SO4 shows a decreasing trend on Cr(VI) adsorption. The SMG exhibits disinfection action (40 μg/L) toward E. coli bacteria with 100% killing efficacy and low toxicity (0.1 ng/nL) toward zebrafish without inducing any abnormalities. The SMG is reusable and successfully works on drinking water sources, suggesting that SMG is a preferred adsorbent for safe drinking water.

The antioxidant activity (AA), total phenolic content (TPC), and total flavonoid content (TFC) of selected Indonesian Zingiberaceae herbs were determined. An optimization extraction procedure was conducted by using Taguchi L16 orthogonal array. Four chemical assays were applied, including 2,2-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity assay, H2O2 scavenging activity assay, Folin–Ciocalteau (F–C) assay, and NaNO2-AlCl3-NaOH assay, which revealed remarkable differences in AA, TPC, and TFC. The result indicated the diversity of AA composition among the herbs, and C. longa exhibited the highest AA. HPLC-PAD analysis revealed that curcumin was present in five high antioxidant herbs, and the highest amount was in C. longa. Pearson correlation analysis indicated that the identified TPC and TFC were significant contributors to AA, and curcumin was likely the main contributing antioxidant compound. Our approach concluded that C. longa is the greatest source of natural antioxidants among 12 Indonesian indigenous Zingiberaceae herbs. The use of a mixed-method approach to augment the findings of solitary methods might facilitate future researchers to uncover deeper and hidden meanings.

A novel method has been developed to recharge and rejuvenate perovskite solar cells by immersing the device into methyl ammonium iodide (MAI) solution and heating at 70 °C for 40 s.