Zhigen Wu

To date, few studies have been carried out on the influence of the mixing effects of soils and remediation agents on the remediation effects of benzo[a]pyrene (B[a]P) in contaminated soils. In this study, the mixing effects of soils and remediation agents and the degradation effects of B[a]P under different stirring conditions were investigated by combining stirring tests with discrete element method (DEM) simulation. The results from the stirring tests indicated that the mixing effects of two-stage (C_Drill) drill bits were better than first-stage one-line (A_Drill) and first-stage cruciform (B_Drill) drill bits. The mixing quality of C_Drill at the drilling/raising rates of 2, 2.5, 3, 4, and 7.5 cm/min were 42.13%, 43.20%, 43.98%, and 43.30%, respectively. In terms of the results from the B[a]P oxidation remediation tests, the contaminated soils mixed with C_Dril have better remediation effects for B[a]p than those mixed with A_Dril and B_Dril, since B[a]p in contaminated soils stirred and mixed using C_Drill could not be detected after oxidative degradation. The present study results have proved that the mixing effects of soils and remediation agents could significantly affect the remediation effects of contaminated soils with polycyclic aromatic hydrocarbons (PAHs).

An analytical solution is conducted on forced convection in a metal foam partially filled plate channel under asymmetric heat flux conditions, with the aim of optimizing heat transfer performance. The Darcy–Brinkman model and the local thermal non-equilibrium (LTNE) model are employed to predict heat transfer characteristics under varying heat flux ratios (q₁/q₂). Key parameters such as the free zone height, pore density, and thermal conductivity ratio significantly influence heat transfer efficiency. The results indicate that the height of the free region has a greater impact on the flow distribution than porosity and pore density. When the non-dimensional height of the free region is 0.3, the flow fraction in the free region reaches 80%. When the free zone height is H = 0.1, the heat exchanger heat transfer coefficient reaches its maximum value, and the combination of copper (Cu) and R134a refrigerant demonstrates superior convective heat transfer performance compared to the empty channel. Their optimization can lead to substantial improvements in the heat transfer effectiveness of the channel.

Thermal desalination evaporation of high-salt wastewater has been widely used in industry because of the proposed concept of ‘zero liquid discharge’. However, due to the high content of Ca2+ and Mg2+ in high-salt wastewater, the heat exchanger, as the main treatment equipment, suffers from serious scaling problems. This review presents descaling and scale inhibition technologies of high-salt wastewater. The advantages and disadvantages of various technologies are summarized and analyzed to provide theoretical support for the research of descaling and anti-scaling of heat exchangers with high-salt wastewater. In future industrial development, the synergistic application of electromagnetic water treatment technology and scale inhibitors can significantly improve the anti-scaling effect, which can reach over 95% stably. Furthermore, the addition of a physical field can also expand the application range of scale inhibitors.