Preparation of Sulfonate-Grafted Tetraphenylethylene-Based Hyper-Cross-Linked Polymers for Efficient Adsorption of Organic Dyes in Aqueous Solutions
Xiaobo Luo, Shiyuan Zhou, Shiyuan Zhou, Zhou Sheng, Zhou Sheng, Danfeng Wang, Zhang Ye, Xiaoqiong Hao, Guangfeng Liu, Ping Liu, Peiyang Gu
Abstract
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 m 2 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 ( k 2 ) 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.