A novel and simple apparatus for the continuous generation of hydroxyl radicals has been constructed for the first time. In this paper, we focused on the investigation into the kinetic study of hydroxyl radical formation in the preparation process. The effects of the process parameters (such as the electrolyte solution concentration, graphite dosage, the applied current strength, and air flow rate) on the concentration of hydroxyl radicals were investigated in detail. The concentration of hydroxyl radicals first increased with the concentration of sodium dodecyl benzene sulfonate electrolyte solution, graphite dosage, applied current strength, and air flow rate, and then decreased. The concentration of ·OH and time well fit a third-order model of {C(·OH) = B₁ × t + B₂ × t² + B₃ × t³ + intercept}. The highest concentration of hydroxyl radicals was 7.98 × 10⁻³ mol L⁻¹ under the following conditions: sodium dodecyl benzene sulfonate concentration 10.0% (w/v), graphite dosage 5.0 g, applied current strength 10 mA, and air flow rate 1.0 L h⁻¹. Our hydroxyl radical generation method can achieve the preparation of higher-concentration hydroxyl radicals continuously without using strong acid reagents. Moreover, our method has low energy consumption by using milliampere-level current. It is a green and efficient method for the generation of hydroxyl radicals. The kinetic study of hydroxyl radical generation can quantitatively predict the concentration changes with process parameters and provide a good prediction of hydroxyl radical generation, which is crucially important in industrial applications.

A novel, simple and efficient method by the combination of hydroxyl radicals and electrical exfoliation of graphite for the green production of high-quality graphene from graphite was first developed in our self-manufactured exfoliation apparatus. In this work, we focused on the investigation of the roles of various electrolyte systems for the exfoliation of graphite. Sodium chloride, sodium hydroxide, poly vinyl pyrrolidone (PVP), dodecyl trimethyl ammonium bromide (DTAB) and sodium dodecyl benzene sulfonate (SDBS) were tested as the electrolyte. The yields of the graphene product in sodium hydroxide, PVP, DTAB, sodium chloride and SDBS electrolyte system were 32.9%, 34.0%, 45.2%, 77.5% and 83.5%, respectively. The experimental result demonstrated that graphite can be successfully exfoliated to graphene in these electrolytes, with SDBS showing the best exfoliation effect. We further investigated the effects of process parameters on the graphite exfoliation in the SDBS system by single factor experiments. The obtained optimal process parameters were as follows: graphite dosage, 5.0 g; SDBS solution concentration, 10.0% (w/v); applied current strength, 10 mA; air flow, 1.0 L h⁻¹; and exfoliation time, 3 h. At these conditions, the yield of the graphene product was 89.7%. TEM results revealed that the graphene product possessed the characteristic features of a thin-layer graphene sheet. XRD results showed that the graphene products still maintained the structures of carbon atoms or molecules. FT-IR and Raman results indicated that the products exhibited the characteristic peaks and the absorption peaks of graphene. AFM test results revealed that the layer number of graphene product obtained was about 2, while the layer numbers of the graphene products obtained from sodium hydroxide, PVP, DTAB and sodium chloride systems were 30, 20, 4 and 3, respectively, at the same experimental conditions. The observed exfoliation effect in the SDBS system was due to its good electrical conductivity, which was favorable for the formation of hydroxyl radicals in exfoliation. Furthermore, SDBS has good hydrophilic properties and can enable even dispersion of graphite in the system. These two effects facilitated the exfoliation of graphite to form good-quality graphene. SDBS as the electrolyte did not corrode the electrode, and it could be recycled; also, it does not pollute the environment and reduces the production cost, which is favorable for mass production.

A novel, simple and efficient method, involving the combination of hydroxyl radicals and electrical exfoliation of graphite for the green production of high-quality graphene from graphite, was developed for the first time. The process parameters were optimized by single factor experiments; the optimal conditions were 4.0 g graphite dosage, sodium chloride solution with concentration of 5.0% (w/v), applied current strength of 10 mA, and air flow rate of 1.0 L h⁻¹ for 3 h. Under the optimized conditions, graphite was successfully exfoliated to graphene. SEM and TEM results revealed that the graphene product has the characteristic features of a thin-layer graphene sheet. XRD results showed that the graphene products still maintained the structure of the carbon atoms or molecules. FT-IR and Raman results indicated that the products have the characteristic peaks and absorption peaks of graphene. AFM imaging results reveal that the layer number of the graphene product obtained by this method is about 3, while the graphene products from the individual hydroxyl radical oxidation and electrical exfoliation processes were 50 and 133 layers, respectively, under the same experimental conditions. The good quality of the graphene product can be attributed to the synergistic effect between the strong oxidation of the hydroxyl radicals and electrical exfoliation. The proposed method has the advantages of simple operation, mild preparation conditions, non-utilization of aggressive reagents, recycling of the reaction medium, etc. Thus, this method could serve as a green and efficient alternative for the production of graphene and its derivatives in industry.

In view of the technical difficulties in the preparation of graphite intercalation compound (GIC) such as complex processes, the need to use strong acid reagents, and the product containing corrosive elements. A novel, efficient and simple method used sodium bicarbonate as intercalation agent was developed, which combined with mechanical force and chemical method for the green production of GIC. The production parameters were optimized by the single factor experiments, the optimal conditions were the ball mill speed 500 r/min for 4 h (6 mm diameter of the stainless-steel beads as ball milling media), the decomposition temperature 200 ℃ for 4 h, and 1:1 mass ratio of flake graphite to sodium bicarbonate. SEM results revealed that the prepared product appears the lamellar separation, pores, and semi-open morphology characteristic of GIC. FT-IR results indicated that the preparation method does not change the carbon-based structure, and the sodium bicarbonate intercalant has entered the interlayer of graphite flakes to form GIC. XRD results further showed that the GIC products still maintained the structure of carbon atoms or molecules, and the sodium bicarbonate intercalation agent has entered the interlayer of the graphite, and increased the interlayer distance of the layered graphite. The expandability of GIC products was studied, and the results show that it was expandable, and the expandable volume of GIC products prepared under optimal conditions has reached 142 mL/g. The theoretical basis for large-scale production was provided by studied the mechanism of the preparation method and designed the flow chart. The method has the advantages of simple process, products free of impurities, no use of aggressive reagents, process stable, and does not pollute the environment, being favorable to mass production, and provided new preparation method and idea for two-dimensional nanomaterials with preparation technical difficulties.

In this paper, a novel, effective, and feasible autonomous phase control algorithm based on the extended Kalman filtering (EKF) and neural network is firstly developed for addressing the problems of configuration maintenance of remote sensing satellite constellation. A balanced moment arm optimization method is employed to design the installation structure layout of the chemical propulsion system in the satellite. On that basis, an autonomous orbit control strategy is presented for controlling the phase of satellites, and the EKF algorithm is utilized to determine the orbit used to calculate the satellite phase. A radial basis function (RBF) neural network-based attitude control method is proposed to solve the attitude disturbance problem in the course of the phase control, and the RBF neural network is utilized to approximate the coupling torque of the orbit control. The simulation results demonstrate the feasibility of the designed automatic phase control strategy of the satellite.

A new kinetic model, So's three-step kinetic model, was used to study the kinetics of graphene oxide (GO)-assisted ethanol reflux extraction (GERE). An experimental design to investigate the effect of five single factors (extraction temperature, dosage amount of GO, concentration of ethanol aqueous solution, the ratio of liquid to solid, rotating speed) on the kinetic extraction of total flavonoids was materialized. From the single factors experiments, we found that the extraction process is mainly controlled by internal diffusion, and the extraction rate increases with the growth of GO dosage, ethanol concentration and liquid–solid ratio at 30–70 °C; moreover, the rotating speed had little effect. The effective internal diffusion coefficient (D′) and the activation energy (E_a) of total flavonoids extracted by ERE and GERE were also studied, respectively. Results showed a good prediction of So's three-step kinetic model for extraction kinetics in all experiments, which gave the possibility for estimating the initial rate and extent of GERE.