Functionalized boron nitride ceramic nanofiltration membranes for semiconductor wastewater treatment

Abstract

Boron nitride (BN) nanomaterials were used to enhance the separation performance of membranes due to their ability to create more nanochannels with excellent chemical stability. Two different functionalization methods, including strong acid oxidation and a tannic acid (TA)-assisted exfoliation process, were explored to introduce hydroxyl groups on BN surfaces. We also propose a novel method for the fabrication of ceramic nanofiltration (NF) membranes with optimal functionalized BN loadings on ceramic ultrafiltration (UF) membrane substrates. The functionalized BN-coated ceramic NF membrane exhibited a promising separation performance for both particulate and organic contaminants by modifying the surface chemistry of the ceramic membrane and reducing membrane pores by adding nanochannels. Compared to the performance of the ceramic UF membrane alone, filtering ceramic UF membrane permeate through the functionalized BN-coated ceramic NF membrane increased an additional rejection of 20.4% for dissolved silica and 59.8% for humic acid, respectively. Collectively, the results provide a basis for the optimization of membrane-based semiconductor wastewater treatment by creating a hybrid of the ceramic UF and NF membrane processes. In turn, our findings not only facilitate the achievement of national regulatory standards for wastewater discharge but also provide crucial insights into the transport dynamics of particulate and organic contaminants.