Facile synthesis of hydroxyl enriched microporous organic networks for enhanced adsorption and removal of tetrabromobisphenol A from aqueous solution

Here we report the rational design and facile synthesis of hydroxyl-enriched microporous organic networks (MON-OH and MON-2OH) for enhanced and efficient adsorption and removal of a typical brominated flame retardant tetrabromobisphenol A (TBBPA) from aqueous solution. Introducing of hydroxyl groups into MONs' networks lead to the significant improvement of their hydrophilicity and adsorption capacity for TBBPA. Rely on the good hydrophobicity and predesigned hydrogen bonding sites, the synthesized MON-2OH gave a large adsorption capacity of 326.8 mg g(-1) for TBBPA, which is much higher than MONs and many other reported sorbents. The adsorption of TBBPA on MON-2OH followed Langmuir and pseudo-second-order kinetic adsorption models. The TBBPA adsorption capacity was independent on ionic strength (0-30 mg g(-1)), humic acid (0-40 mg g(-1)) and pH (5.0-8.0). MON-2OH also gave good stability and reusability and owned good practicability for the removal of TBBPA from wastewater samples. Efficient adsorption and removal of other biphenol pollutants was also achieved on MON-2OH. The adsorption mechanisms of TBBPA on MON-2OH were also well elucidated. This work provides a promising way to design and synthesize efficient adsorbents for TBBPA, which may also promote the design, synthesis and application of functionalized MONs in environmental and material science.