Zhaohui Zhang,Yun Liu,Bin Zhao,Junjing Li,Liang Wang,Cong Ma
In this study, the reductions of long-term irreversible membrane fouling in integrated and separated MIEX-UF processes were explored over a prolonged experimental period. The mechanism leading to the significant difference in membrane fouling behaviors of the two processes was systematically analyzed. The results show that the chemical cleaning frequency and the rate of chemically irreversible membrane fouling formation were decreased by 50% and 49%, respectively, in the integrated process compared to the separated process. Further analysis suggested that MIEX adsorption was unrelated to the different membrane fouling behaviors between the two processes. The effect of the resin layer on filtration and backwashing was the dominate mechanism leading to the more excellent anti-fouling performance of the integrated process. The stronger adhesion force of pollutants-MIEX enable the mixed cake layer formed in the integrated process to maintain good water permeability and easy to be removed by backwashing. The adhesion force of pollutants-MIEX was significantly affected by the saturation level of resin particles and less affected by resin regeneration. During the early period of long-term filtration experiment and the initial stage after every resin replacement, the low saturation degree of resin particles guaranteed the improved effect of the resin layer always existed.
Membrane-free electrodeionization (MFEDI) has been tested successfully for high purity water production in our previous work. However, in order to prevent the constant backward migration of cationic or anionic ions, to achieve equally effective regeneration for both the cationic and anionic resins, and to get neutral concentrate, the electrodes had to be reversed during regeneration. This not only complicated the regeneration process, but also decreased the water recovery and the electrode lifetime. In this work, we improved the resin layer structure and investigated the regeneration performance of MFEDI without electrode polarity reversal . A total of 30 operational cycles were examined. Effective regeneration was achieved. The effluent conductivity was 0.055–0.060 μS/cm only; the average pH value of the concentrate was 7.2; the water recovery was 90%; and the energy consumption was 0.71 kWh/m 3 water.
This study focused on bonding strength improvement between aluminum alloy and carbon fiber reinforced polymer (CFRP) composite. Laser engraving method was used to create grooves on surface of aluminum substrate, and resin pre-coating (RPC) was used to disperse high-viscosity resin into resin pre-coating solution to be introduced into pre-fabricated structure, which contributed to reducing bonding defects and constructing short aramid fiber/epoxy (SAFE) bonding layer after full evaporation of acetone to improve mechanical interlocking. The results showed bonding strength of composite with engraving space of 0.2 mm and RPC with short aramid fibers was 20.32 MPa, 220.4 % higher than the base. The failure mode was changed from debonding failure on aluminum surface to delamination failure of CFRP. The research confirmed laser engraving and RPC as simple and effective combined methods on improving bonding strength of aluminum-CFRP composites, which could provide a reference for other metal to manufacture high-performance hybrid composites.
危险品化学品经营许可证（带存储）