Investigating the fouling potential of the metal‐silicate complex on membrane by response surface method (RSM)

Abstract

BACKGROUND To optimize the filtration efficiency of membrane systems for chemical mechanical polishing (CMP) wastewater, the fouling potential of silica, aluminum‐silicate complex, and copper‐silicate complex was investigated by the response surface method. RESULTS The mathematical models for three kinds of fouling were successfully developed based on the SDI0.1μm‐1atm and MFI0.1μm‐1atm to describe the fouling potential. These models indicate that the metal‐silicate complex fouling was severe at a neutral pH. Moreover, the models reveal that the effect of metal ions on fouling potential is significant. Compared with the feed solution conditions of 500 mg SiO2 /L and pH 7.5, when 1 and 5 mg Al3+/L are added, the MFI0.1μm‐1atm values increase by 109% and 156%, respectively. In addition, when 1 and 5 mg Cu2+/L are added, the MFI0.1μm‐1atm values increase by 210% and 313%, respectively. CONCLUSION The decrease in filtration efficiency was in the order of copper‐silicate complex > aluminum‐silicate complex > silica. Therefore, the fouling potential increased significantly when the influent contained trace metal ions (Al3+ or Cu2+) at a near‐neutral pH, demonstrating the importance of managing pH and metal ions in CMP wastewater for membrane systems. In addition, the MFI0.1μm‐1atm is more suitable than the SDI0.1μm‐1atm for evaluating fouling potential. The SDI0.1μm‐1atm has limited value and a narrow range for fouling potential measurement. In contrast, the MFI0.1μm‐1atm is more sensitive and has a more comprehensive detection range. © 2023 Society of Chemical Industry (SCI).