Dimethoxypillar[5]arene knitted porous polymers for efficient removal of organic micropollutants from water

Porous organic polymers containing macrocycles are promising adsorbents to remove organic micropollutants from water. However, it is still a big challenge to achieve the balance between economy and performance in real-world application. This study aimed at tackling this challenge by verifying the feasibility of dimethoxypillar[5]arene (P[5]) as a universal knitting crosslinker. Herein, four typical aromatic building blocks were selected and the corresponding P[5] knitted porous polymers with high cost-effectiveness were successfully obtained by a simple Friedel-Crafts reaction with all the yields in excess of 100%. We have demonstrated the significant roles of P[5] content and surface area on the adsorption kinetics and adsorption capacity, respectively. Specially, P[5] knitted 1,3,5-triphenylbenzene (P[5]-TPB) showed the superior adsorption performance among them. The thermodynamic studies certified the spontaneous and exothermic nature, while the mechanism studies revealed that hose-guest and hydrophobic interactions played fundamental roles in the adsorption process. The studies of flow-through adsorption and adsorption at environmentally relevant concentrations further displayed the superior adsorption performance of P[5]-TPB for practical application. The high cost-effectiveness combined with the excellent adsorption properties of P[5]-TPB achieved the balance between economy and performance, demonstrating great potential as promising adsorbent for real-world application. This work paves a way for the synthesis of cost-effective advanced porous polymers with host-guest property for versatile applications.