Asia-Pacific Journal of Chemical Engineering最新文献

To improve the utilization rate of herbicides and reduce their environmental residues, it is urgent to develop a simple and low-cost method to prepare slow-release pesticides. In this study, a biochar (280CPFe) with a high surface area and rich oxygen-containing functional groups was synthesized by low temperature (280°C) boiling strategy, which was used as a carrier to prepare pH-responsive slow-release herbicide. The obtained biochar has a high adsorption capacity of 153.59 mg·g⁻¹ for quinclorac (QNC). The release rates of QNC-280CPFe are 21%, 56%, and 90% at the initial pH of 3, 5, and 11, respectively. The controlled release behavior of QNC-280CPFe is related to its adsorption mechanism, in which the pore filling and functional group adsorption are mainly responsible for the adsorption of QNC on 280CPFe. Compared with QNC alone, QNC-280CPFe slow-release herbicide has a good control effect on Barnyard grass but does not affect the normal growth of rice. Therefore, this study provides a simple, low-cost cost, and environmentally friendly biochar carrier for preparing slow-release herbicide, improving its utilization rate and reducing its environmental pollution risk.

Layered oxides are considered to be potential cathodes for sodium-ion batteries based on high theoretical capacity and ease of synthesis. However, the complex phase transition caused by interlayer sliding in layered oxides leads to poor cycling stability, which will hinder their further application. Here, we designed a newly O3-type layered cathode NaNi_0.3Co_0.2Cu_0.1Mn_0.2Ti_0.2O₂ based on high-entropy to achieve highly reversible phase transition behavior. It reveals 132 mAh g⁻¹ at 0.2 C within 2–4 V increasing the energy density to 408 Wh kg⁻¹ and it shows an outstanding rate capability of 90 mAh g⁻¹ at 80 C (84.90% capacity retention after 1,500 cycles at 80 C). In-situ XRD shows that reasonable design of high-entropy components in layered material can achieve the purpose of delaying the occurrence of phase transition and DFT calculations show that the introduction of Co in transition metal layers can effectively improve the rate performance of the material. This work is of great significance in guiding the design and synthesis of highly stable layered cathode materials for sodium-ion batteries.

This study investigates the environmentally friendly synthesis of ZrO₂-NdO mixed nanomaterial using green reducing and capping agents derived from the plant Amaranthus viridis. X-ray diffraction (XRD) analysis confirmed the successful synthesis of the mixed nanomaterial, revealing an optical band gap of 2.5 eV. The morphology was characterized by spherical-shaped particles with an average size ranging from 66 to 77 nm. The synthesized ZrO₂-NdO mixed nanomaterial was evaluated for its potential application as an electrode material in energy devices, specifically for pseudocapacitors and water splitting studies. Electrochemical performance was assessed using cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) techniques. Notably, a specific capacitance of 573.5 F/g was achieved through CV at a scan rate of 2 mV/s. Fabricated electrocatalyst was further analyzed for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), and the results showed better over potential value of 164 mV for HER studies. The stability analysis further endorsed the large-scale commercialization possibility of ZrO-NdO-based electrode material.

In this paper, a novel air-cooled supercapacitor thermal management system (STMS) based on the corner deflectors and the inclined inlet and outlet was proposed. The temperature and velocity fields were simulated and analyzed by CFD. Moreover, the heat dissipation effect of different STMSs was analyzed against each other. The results showed that the STMS proposed had a better heat dissipation effect when the inclined angle of inlet and outlet was appropriate, in which the maximum temperature (T_max) and the maximum temperature difference (ΔT_max) of the module could be reduced by 10.3% and 34.6%. And it is shown that the structure with inclined inlet and outlet plays an important role for the heat dissipation capability of the STMS proposed. And it has experimentally proven its heat dissipation ability. Consequently, the impacts of inclined angle (α), monomer spacing (d_c), and the distance between monomer and module shell (d_x, d_y, and d_z) on the heat dissipation effect were deeply analyzed. For the STMS arranged in four rows and three columns, it had a better heat dissipation effect when inclined angle was in the range of 40° to 50°. The results showed that the structural parameters had a large influence on the T_max and ΔT_max. Besides, it had shown that the temperature curves of the T_max and ΔT_max had a main trend of “decreasing and then increasing” when the monomer spacing as well as the distance between monomer and module shell are taken from 1 mm to 5 mm. It implies that a small spacing (1 mm to 2 mm) will hinder the air circulation and reduce heat dissipation, and a large spacing (3 mm to 5 mm) will reduce the average flow rate of air and reduce the efficiency of heat transfer.

A series of interactive experiments are conducted to analyze the drag reduction technology with a rotating disk apparatus that combines microgroove structure and drag-reducing additives including polyethylene oxide (PEO), cetyltrimethyl ammonium chloride (CTAC), and sodium salicylate (NaSal). By varying the disk type, concentration of drag-reducing additives, temperature, and Reynolds number (Re), the corresponding drag reduction rates are obtained effectively. The experimental results indicate that adding CTAC strengthens the heat degradation and shear resistance of PEO; while PEO can enhance the ability of CTAC to form micellar structures and balance energy distribution at low concentrations. Moreover, the synergistic effect of these two additives presents a better drag reduction performance with a maximum drag reduction rate of 24.1%; while the microgroove structure enhances the effect of active drag reduction. Therefore, the combination of active and passive drag reduction technology broadens the application of energy saving and consumption reduction in hydraulic rotating machinery.

The attrition behavior of HZSM-5 zeolite catalyst particles at room temperature was investigated in a laboratory-scale fluidized bed. The effects of three fluidization conditions on particle attrition were investigated, and a new attrition model was proposed. The results demonstrate that the attrition rate is inversely proportional to the initial particle size and proportional to the apparent gas velocity. After increasing to 80 μm and .3 m/s respectively, they are no longer the main factor affecting attrition. The effect of bed pressure on attrition rate is nonlinear, and the lowest attrition rate is obtained when the diameter-height ratio is 1:1. Unsteady attrition stage can be divided into initial stage and deceleration stage. Surface delamination dominates particle attrition throughout the whole process, and bulk fracture is the dominant mechanism only in the deceleration stage. Based on the Gwyn equation, a new attrition model in the form of cubic polynomial is established with the ratio of total attrition rate to unstable attrition rate P as a parameter. The model has high accuracy and repeatability and is suitable for various fluidization conditions. It can effectively describe the attrition process and change rule of particles and reasonably predict the fluidization attrition rate of particles.

In this study, we synthesized eight palladium-based catalysts using two carriers, ZrO₂ and MCM-41. These catalysts were used for the degradation of condensed tannins extracted from larch bark. The average polymerization degree and degradation rate of the products were used as indicators to evaluate the efficiency of degradation. The effects of different Pd:Cu loading ratios under the same carrier conditions and the effects of different carriers under the same Pd:Cu loading ratio were investigated. The results revealed that when the carrier was kept constant, the Pd:Cu ratio of 1:1 exhibited the highest efficiency in degrading condensed tannins. Moreover, when the Pd:Cu loading ratio was the same, the degradation efficiency was higher when ZrO₂ was used as the carrier. Based on these findings, the catalyst (Pd₁-Cu₁)₅/ZrO₂ (where “1” are the molar ratios of Pd to Cu added during the preparation of the catalyst and where ‘5’ is the mass percentage of Pd/Cu metal to total catalyst, i.e., 5 wt%), with ZrO₂ as the carrier and a Pd:Cu ratio of 1:1, demonstrated the highest degradation efficiency, with a degradation rate of 73.89%. This catalyst successfully reduced the average polymerization degree of condensed tannins from 9.5 to 2.48.

In this study, the adsorption of thiophene compounds (TCs), including thiophene (T), benzothiophene (BT), and dibenzothiophene (DBT), from model fuels was investigated using modified activated carbon (AC). The model fuel, prepared as a single-solute model at a concentration of 2000 ppm based on a mixture concentration of 3000 ppm, served as the basis for the adsorption experiments. Additionally, an examination of thiophene adsorption from commercial fuels, specifically kerosene, was conducted. Experimental data were used to calculate correlated parameters of adsorption isotherms, kinetic models, and the Fisher factor. The pseudo-second-order model demonstrated the best fit to the experimental data. Notably, the adsorbent consisting of 10% Cu⁺ supported on acid-washed activated carbon (A1CN10) exhibited the highest adsorption capacity for TCs, achieving removal percentages of 78%, 96%, and 100% for T, BT, and DBT, respectively. Various methods were employed to investigate the physicochemical properties of the adsorbents, including N₂ adsorption–desorption surface analysis (BET), scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy dispersive spectroscopy (EDS). Furthermore, the regeneration of the adsorbent was studied using two techniques: agitation and ultrasound.

The high aromaticity of fluidized catalytic cracking (FCC) slurry makes it a superior raw material for the production of high-performance carbon materials. In this study, direct thermal polycondensation of aromatic-rich FCC slurries is conducted to synthesize mesophase pitches with a significant anisotropic content. The effects of stirring speed and the pressurized-atmospheric two-stage reaction on the structure and composition of the products are investigated. Thermal stability analysis using thermogravimetric (TG) test, observation of mesophase content and optical structure through polarized light microscopy, characterization of material composition and molecular structure via Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectrum (¹H NMR), as well as comparison of crystal structures using X-ray diffraction (XRD) are performed. The experimental results demonstrate that an increase in the stirring rate leads to a more homogeneous molecular distribution within the reaction system, thereby facilitating molecular contact polycondensation and promoting mesophase growth and development. Furthermore, the pressurized-atmospheric two-stage reaction process also contributes to mesophase development, resulting in products with more cycloalkane structure, improved thermal stability, and optimized optical structure transitioning from mosaic to flow or even domain.

This study aimed to improve the catalytic activity and hydrothermal stability of Cu-SSZ-39 zeolite by coupling it with cerium zirconium oxides (CeZrO_x), which possesses excellent oxidizing ability, and a hybrid catalyst CeZrO_x/Cu-SSZ-39 was prepared. It is found that it exhibited enhanced low-temperature activity, high-temperature activity, and a wider effective temperature range compared to Cu-SSZ-39. Characterization results showed that the CeZrO_x/Cu-SSZ-39 catalyst had a higher concentration of active Cu²⁺ ion species and improved redox properties, which could potentially promote the NH₃-SCR reaction. Additionally, the CeZrO_x/Cu-SSZ-39 catalyst had increased chemisorbed oxygen species on its surface, facilitating the oxidation of NO to NO₂ and enhancing the rate of the SCR reaction. Moreover, even after undergoing hydrothermal aging treatment, the CeZrO_x/Cu-SSZ-39 catalyst exhibited superior catalytic activity and improved hydrothermal stability, surpassing the performance of Cu-SSZ-39. It is found the CeZrO_x coupling allowed the hybrid catalyst to maintain a better specific surface area and pore structure during hydrothermal aging, resulting in reduced activity loss. Therefore, the addition of CeZrO_x enhanced the NH₃-SCR activity of Cu-SSZ-39 zeolite, leading to improved catalytic activity and hydrothermal stability. CeZrO_x/Cu-SSZ-39 catalyst has shown promising aspect for reducing NOx emissions from diesel vehicle exhaust.