Comparative study on the adsorption of creatinine and p-cresol on porous and nonporous hypercrosslinked polymers containing phosphonic acid

In this study, by hydrolysis of the phosphonate esters in these hypercrosslinked polymers (HCPs) made from two bis(α-hydroxyphosphonate) linkers (1, 4-bis[(diethoxyphosphoryl)hydroxymethyl]benzene, 1 ;4,4′-bis[(diethoxyphosphoryl)hydroxymethyl]biphenyl, 2 ) and polyaromatic compounds (9, 9′-spirobi[fluorene], SF; 1, 1′, 2, 2′-tetraphenylethene, TPE; tetraphenylmethane, TPM), respectively, two porous ( SF-1-H and SF-2-H ) and four non-porous ( TPE-1-H, TPE-2-H, TPM-1-H , and TPM-2-H ) hydrophilic HCPs were prepared and characterized in detail. In pure water systems, high adsorption capacities of creatinine and p -cresol on HCPs are exhibited, with saturated adsorption capacities ranging from 96 to 208 mg/g for creatinine and from 82 to 100 mg/g for p -cresol, respectively, with saturation adsorption being attained within 15 minutes. While in the simulated blood system, the porous polymers SF-1-H and SF-2-H show also significant adsorption capacities of creatinine (21 mg/g on SF-2-H ) and p-cresol (21 mg/g on SF-1-H and 24 mg/g on SF-2-H ). The kinetics, thermodynamics and adsorption mechanism of the adsorption process are investigated. This study not only investigated the different adsorption behaviour of creatinine and p -cresol on non-porous and porous materials under different solution conditions, but also provided a method for the preparation of adsorbents with fast and high adsorption capacity, offering new insights for future efficient perfusors.