The removal of heavy metal ions and antibiotics from livestock and poultry wastewater has gained significant attention. Developing dual-functional materials capable of simultaneously removing heavy metal ions and antibiotics from wastewater is a promising strategy. In this study, a functionalization approach was proposed to enhance active sites in covalent organic frameworks (COFs), thereby improving their adsorption performance and maintaining photocatalytic activity. Vinyl-functionalized covalent organic frameworks (COFs-V) were first synthesized in a room-temperature solution. Subsequently, 4-mercaptobenzoic acid was introduced into COFs-V via grafting and chelation to prepare COF@COOH, aiming to modify surface active sites. Fourier transform infrared spectroscopy (FTIR) and in-situ X-ray photoelectron spectroscopy (XPS) confirmed the successful introduction of carboxyl groups into COF@COOH, significantly increasing the number of active sites. The performance and mechanism of COF@COOH in the removal of Cu