Tetrabromobisphenol A (TBBPA) generation and removal paths analysis in printed circuit board (PCB) industrial wastewater: Lab-scale investigations

With the rapid development of printed circuit board (PCB) industry, the problem of the release of tetrabromobisphenol A (TBBPA) during PCB manufacturing processes was recognized and harmful to the receiving water body. In this study, TBBPA generation paths, fates in industrial wastewater in the PCB manufacturing processes were analyzed. Gas chromatograph-mass spectrometer (GC-MS) scanning results showed that the raw materials including solder mask ink, character ink and dry film mainly contained TBBPA. The PCB fabrication procedures, mainly including development, etching, stripping of inner layer manufacturing process, and pattern plating, tin-plating of outer layer manufacturing process, and development during the forming and surface treatment process would introduce TBBPA into wastewater. Flocculation and activated sludge process (ASP) that were commonly used for industrial wastewater treatment were selected to assess their removal capability for TBBPA in the wastewater, both which could remove more than 80% TBBPA. Low pH below 7, increased PAC and PAM dosages, and proper dosing during the slow-stirring stage could enhance the TBBPA removal of flocculation-sedimentation process. The ASP removes TBBPA mainly by the path of adsorption. High activated sludge concentration, low pH, medium-temperature and limited competitive adsorbates (NH4+, Cu2+) were beneficial to remove TBBPA by the ASP.

Automated summary

With the rapid development of the PCB industry, the release of TBBPA during manufacturing processes has become a recognized problem. This study analyzed the generation and fate of TBBPA in industrial wastewater during PCB manufacturing processes. The raw materials and various fabrication procedures were found to introduce TBBPA into wastewater. Flocculation-sedimentation and activated sludge processes were both effective in removing over 80% of TBBPA from wastewater, with various factors affecting their removal capabilities.