As an important precursor and derivate of graphene, graphene oxide (GO) has received wide attention in recent years. However, the synthesis of GO in an economical and efficient way remains a great challenge. Here we reported an improved NaNO₃-free Hummers method by partly replacing KMnO₄with K₂FeO₄and controlling the amount of concentrated sulfuric acid. As compared to the existing NaNO₃-free Hummers methods, this improved routine greatly reduces the reactant consumption while keeps a high yield. The obtained GO was characterized by various techniques, and its derived graphene aerogel was demonstrated as high-performance supercapacitor electrodes. This improved synthesis shows good prospects for scalable production and applications of GO and its derivatives.

As one of the simple and efficient routes to access two-dimensional materials, liquid exfoliation has received considerable interest in recent years. Here, we reported on high-efficient liquid exfoliation of hexagonal boron nitride nanosheets (BNNSs) using monoethanolamine (MEA) aqueous solution. The resulting BNNSs were evaluated in terms of the yield and structure characterizations. The results show that the MEA solution can exfoliate BNNSs more efficiently than the currently known solvents and a high yield up to 42% is obtained by ultrasonic exfoliation in MEA-30 wt% H2O solution. Finally, the BNNS-filled epoxy resin with enhanced performance was demonstrated.

Partially reduced graphene oxide-Fe₃O₄ composite was prepared through in situ co-precipitation and used as an efficient adsorbent for removing Pb(II) from water. The composites were characterized by X-ray diffraction, high-resolution transmission electron microscopy, X-ray photoelectron spectra, Fourier transformation infrared, Raman spectrometer, N₂ adsorption–desorption, vibrating sample magnetometer, and zeta potential analyses. The impacts of pH, contact time, adsorbent dosage, temperature, and foreign substances on Pb(II) adsorption performance were investigated. The adsorption mechanism, kinetics, and thermodynamics were analyzed. The results indicate that Fe₃O₄ is homogeneously anchored inside the thin graphene sheets, with a particle size of 15–20 nm, resulting in a very low remanence and coercivity. The composite shows excellent and efficient adsorption performance toward aqueous Pb(II): adsorption equilibrium was reached in 10 min with the adsorption percent and quantity of 95.77% and 373.14 mgċg⁻¹, respectively, under a condition of pH = 6, adsorbent dosage 250 mgċL⁻¹, and Pb(II) initial concentration 97.68 mgċL⁻¹, with the subsequent magnetic separation taking only 10 s. The adsorption performance is dependent on adsorbent dosage. A lower dosage favors a higher adsorption quantity, implying a strong adsorptive potential for partially reduced graphene oxide-Fe₃O₄. The adsorption quantity reached 777.28 mgċg⁻¹, given the dosage 100 mgċL⁻¹. The adsorption is monolayer chemisorption, the whole process of which is controlled by chemisorption and liquid film diffusion. In terms of thermodynamics, the adsorption is an exothermic and spontaneous process.