Modified biochar through synergistic strategies for enhanced extraction of bisphenol compounds in marine water

The increasing concern surrounding environmental pollution necessitates effective monitoring of emerging organic pollutants, especially for bisphenol compounds (BPs). These compounds are prevalent in various industries and have been detected in trace amounts across different ecosystems, raising significant health concerns. Current monitoring techniques often rely on extensive use of extraction solvents, large sample sizes, and expensive materials. Therefore, there is a pressing need for the development of cost-effective, stable, and eco-friendly pretreatment methods to enhance monitoring efficiency.

A novel biochar from Gynostemma pentaphyllum, designated PBAGB, synthesized through a waste-to-wealth strategy that integrates K₂CO₃ activation, ball-milling, and plasma treatment. This innovative approach resulted in a biochar with high specific surface area, abundant oxygen-containing functional groups, and numerous defect sites. The modifications significantly enhanced the active sites available on PBAGB, which was then employed as a solid-phase microextraction (SPME) fiber for extracting bisphenols (BPs). Compared to commercial fibers, the PBAGB-coated fiber demonstrated excellent stability, improved extraction performance, and lower production cost. Coupled with ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), the method achieved good linear ranges (5-5000 ng L^-1), low detection limits (0.39-2.9 ng L^-1), and satisfactory relative recoveries (80.4-119.9%), allowing for efficient determination of BPs in 21 marine samples from the Beibu Gulf.

The work presents a more sustainable, practical, and effective sample pretreatment technique utilizing direct-immersion SPME (DI-SPME) coupled with UPLC-MS/MS for environmental monitoring of trace BPs in Beibu Gulf, following a waste-to-wealth strategy. It emphasizes the practical application of PBAGB-coated fibers in extracting BPs and assessing the ecological risks posed by trace BPs.