Selective adsorption of bisphenol A by organic–inorganic hybrid mesoporous silicas

Organic–inorganic hybrid mesoporous material (Ph-MS) was synthesized by co-condensation of phenyltriethoxysilane and tetraethoxysilane. Ph-MS, which had pore size of 0.96 nm and surface area of 750 m2/g, exhibited mesoscopic orderness and suitable textural properties to act as a potential adsorbent for bisphenol A (BPA), which is one of the endocrine disrupting chemicals. Ph-MS adsorbed most amount of BPA faster than powder activated carbon (PAC), and the kinetic adsorption data for Ph-MS was fitted well with the pseudo-second-order kinetic model. Maximum adsorption capacities of adsorbents were estimated from isotherm data using Langmuir model. Ph-MS exhibited high adsorption affinity to BPA showing large adsorption capacity of 351 mg/g, while showing little adsorption affinity to phenol (40 mg/g). PAC, which is one of the general adsorbents for organic compounds, showed large adsorption capacity for both BPA (337 mg/g) and phenol (253 mg/g). Adsorption selectivity of Ph-MS, defined as a relative equilibrium distribution coefficient, KRD, for BPA against phenol, was at least 5 times larger than that of PAC, showing high adsorption selectivity for BPA. The selective adsorption behavior of Ph-MS was discussed using the results of material characterizations including X-ray diffraction, N2 adsorption/desorption measurements, and Fourier transform infrared spectroscopy, and the results of adsorption experiments.

A phenyl-functionalized mesoporous silica, Ph-MS, synthesized by co-condensation method showed high adsorption affinity and selectivity for BPA against phenol. The large adsorption affinity and selectivity for BPA of Ph-MS seems to be ascribed to the hydrophobic phenyl groups and hydrophilic hydroxyl groups of Ph-MS, which can lead to relatively strong π-π interaction and hydrogen-bonding with two benzene rings and two hydroxyl groups of BPA, respectively.Figure optionsDownload as PowerPoint slideResearch highlights
► A phenyl-mesoporous silica (Ph-MS) was prepared via co-condensaton method.
► Ph-MS showed high adsorption affinity and selectivity for bisphenol A.
► The large adsorption selectivity seems to be ascribed to the surface properties of Ph-MS.