Preparation of Sulfonate-Grafted Tetraphenylethylene-Based Hyper-Cross-Linked Polymers for Efficient Adsorption of Organic Dyes in Aqueous Solutions

Superhydrophilic hyper-cross-linked polymers (HCPs) have become useful adsorbents for dye disposal due to their ultrahigh surface areas, permanent pores, and excellent water dispersion. Herein, a simple synthetic method has been proposed for the construction of hydrophilic tetraphenylethylene (TPE)-based HCPs via molecular knitting and subsequent one-step sulfonation, aiming to significantly improve the adsorption performance toward cationic dyes. Compared to the hydrophobic precursor with a surface area of up to 1561 m2 g–1 (HCTPE), the target sulfonated HCP named SHCTPE has a lower surface area but improved hydrophilicity and adsorption affinity (primarily electrostatic interaction) toward representative cationic dyes including methylene blue (MB) and rhodamine B (RhB), demonstrating impressive adsorption rates with a >99% removal efficiency (η) in only 5 s with pseudo-second-order rate constants (k2) of 58.7 and 83.4 g mg–1 min–1, respectively. The adsorption capacity also reached 1410 mg g–1 for MB and 1096 mg g–1 for RhB, surpassing most of the HCP-based adsorbents. More importantly, SHCTPE exhibited excellent stability after five cycles, and its corresponding adsorption-treated solution showed considerable biocompatibility in the growth of wheat seeds. Our strategy may provide an approach to develop superhydrophilic HCPs for efficient adsorption of organic dyes in aqueous solutions.