CdS exhibits excellent photochemical properties and high quantum efficiency in the visible light region, however, its catalytic stability is significantly compromised by photocorrosion. Constructing CdS/Mg?CdIn2S4 heterojunctions can effectively suppress photocorrosion and enhance the material's overall stability. In this study, CdS nanowires (CdS NWs), CdS nanoparticles (CdS NPs), and Mg?CdIn2S4 nanosheets (NSs) were prepared using the ion exchange method, and heterojunctions of 5% CdS NWs/Mg?CdIn?S? (5% by mass fraction of CdS NWs) and 5% CdS NPs/Mg?CdIn?S? (5% by mass fraction of CdS NPs) were constructed. The photocatalysts were characterized using X?ray diffraction (XRD), UV?vis diffuse reflectance spectroscopy (DRS), Fourier?transform infrared (FT?IR) spectroscopy, N2 adsorption?desorption isothermal analysis, transient photocurrent measurements, and electrochemical impedance spectroscopy. The results confirmed the successful construction of both CdS NWs/Mg?CdIn2S4 and CdS NPs/Mg?CdIn2S4 heterojunctions. The catalytic performance was evaluated in a photoreaction system, both heterojunctions possess significant capabilities for the photocatalytic reduction of CO2. Notably, the CdS NWs/Mg?CdIn2S4 heterojunction exhibited superior photocatalytic performance, achieving CO and H2 production rates of 716.7 μmol/(g·h) and 664.3 μmol/(g·h), respectively. These values represent a 46.2?fold and 56.8?fold enhancement compared to pristine Mg?CdIn?S?.Consequently, this work provides a solid foundation for further research and practical applications in the field of photocatalytic CO2 reduction, underscoring significant academic and practical significance.
In order to realize the resource disposal of surplus sludge from sewage treatment plant, ordinary silicate cement was used to solidify it as a building material. The surplus sludge and cement were mixed evenly according to a certain ratio and placed in a standard curing box for 3~28 days. The unconfined compression strength (RC) and total organic carbon (TOC) content of the sludge?cement consolidated body were used as evaluation indicators. It was found that the RC of 28 days for surplus sludge?cement solidified block could reach about 6.9 MPa when mass ratio (Rm) of surplus sludge to ordinary silicate cement and mass ratio (Rl/s) of liquid to solid are 0.63 and 0.31. The RC can't meet the minimum strength requirement of non?sintered brick, but meets the strength requirement for surplus sludge landfill. The total organic carbon value in leached solution (TOCl) of surplus sludge?cement solidified block decreased by about 86% compared with the initial value (TOC0) in consolidated block. It indicates ordinary silicate cement solidified surplus sludge can effectively solidify organics from surplus sludge in the solidified body, which can effectively inhibit the secondary pollution of surplus sludge for land in the landfill treatment process.
The effect of dissolved oxygen (DO) concentration on aerobic granular sludge (AGS) treatment on simulated municipal sewage was studied in SBR reactor. By changing the amount of aeration, the DO concentration in SBR reactor was controlled respectively in the range of 3 mg/L≤ρ(DO)<4 mg/L, 2 mg/L≤ρ(DO)<3 mg/L and 1 mg/L≤ρ(DO)<2 mg/L. The concentrations of COD, NH 4 + -N, NO 3 — -N, NO 2 — -N, TN and P in the effluent were detected. The results show that the removal rates of COD, NH 4 + -N and P are affected little by the DO concentration, but the removal rate of TN is affected significantly. When 3 mg/L≤ρ(DO)<4 mg/L, 2 mg/L≤ρ(DO)<3 mg/L和1 mg/L≤ρ(DO)<2 mg/L, the removal rate of TN is 62.14%, 71.81% and 82.11% respectively; when 1 mg/L≤ρ(DO)<2 mg/L, the removal rate of TN reached the best for the AGS system and the system was stable. The average removal rates of COD, NH 4 + -N and P were 90.43%, 96.97% and 76.00%, respectively.