al2o3 ceramic
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Membranes ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 21
Shengyin Tang ◽  
Wanyi Fu ◽  
Tiantian Song ◽  
Tianhao Tang ◽  
Li Chen ◽  

This work presents an effective approach for manganese-doped Al2O3 ceramic membrane (Mn-doped membrane) fouling control by in-situ confined H2O2 cleaning in wastewater treatment. An Mn-doped membrane with 0.7 atomic percent Mn doping in the membrane layer was used in a membrane bioreactor with the aim to improve the catalytic activity toward oxidation of foulants by H2O2. Backwashing with 1 mM H2O2 solution at a flux of 120 L/m2/h (LMH) for 1 min was determined to be the optimal mode for in-situ H2O2 cleaning, with confined H2O2 decomposition inside the membrane. The Mn-doped membrane with in-situ H2O2 cleaning demonstrated much better fouling mitigation efficiency than a pristine Al2O3 ceramic membrane (pristine membrane). With in-situ H2O2 cleaning, the transmembrane pressure increase (ΔTMP) of the Mn-doped membrane was 22.2 kPa after 24-h filtration, which was 40.5% lower than that of the pristine membrane (37.3 kPa). The enhanced fouling mitigation was attributed to Mn doping, in the Mn-doped membrane layer, that improved the membrane surface properties and confined the catalytic oxidation of foulants by H2O2 inside the membrane. Mn3+/Mn4+ redox couples in the Mn-doped membrane catalyzed H2O2 decomposition continuously to generate reactive oxygen species (ROS) (i.e., HO• and O21), which were likely to be confined in membrane pores and efficiently degraded organic foulants.

2021 ◽  
Vol 2125 (1) ◽  
pp. 012071
Tianpeng Wang ◽  
Mingcheng Sun ◽  
Hongqiang Li ◽  
Shaoyang Xiao ◽  
Yunan Wang ◽  

Abstract Q235 steel /Al2O3 ceramics were brazed with Ag-CuO filler metal at 1050°C and held for 15min in air. When brazing Q235 steel and Al2O3 ceramics directly, it was found that serious oxidation occurred on the steel side during the brazing process. Although the joining was realized, a loose oxide film was formed on the surface of the base steel, which affected the mechanical properties of joints. When Q235 steel with aluminized surface was adopted to braze with Al2O3 ceramics, a Al2O3 layer formed on the surface of Q235 steel successfully avoided the oxidation of Q235 steel, and a compact and defection-free joint was obtained. The typical organization of joint was Al2O3/ CuAl2O4/ CuO/ Ag/ CuO/ CuAl2O4 /Al2O3/ FeAl/ FeAl2/ Fe.

2021 ◽  
Vol 11 (1) ◽  
Yan Zhang ◽  
YanKun Chen ◽  
JianPing Zhou ◽  
DaQian Sun ◽  
HongMei Li

AbstractIn this paper, laser welding-brazing of TC4 Titanium (Ti) alloy and Al2O3 ceramic dissimilar material was carried. The results showed that the Ti alloy and Al2O3 were joined by melting filler metal when the laser was concentrated in the Ti alloy side of the joint. The joint with one fusion weld and one brazed weld separated by remaining unmelted Ti alloy. Laser beam offset the Ti alloy 1.5 mm, Ti alloy would not be completely melted in joint. Through heat conduction, the filler metal melted occurred at the Ti-ceramic interface. A brazed weld was formed at the Ti-ceramic interface with the main microstructure of β-CuZn + Ti2Zn3, β-CuZn and Al2Cu + β-CuZn. The joint fractured at the brazed weld with the maximum tensile strength of 169 MPa.

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