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Steroidal molecularly imprinted polymers (MIPs) and non-imprinted polymer (NIP) were prepared by precipitation polymerization method using cholesterol, deoxycholic acid, and β-sitosterol as the virtual templates, acrylic acid (AA) as the functional monomer, azobisisobutyronitrile (AIBN) as the initiator, and ethylene glycol dimethacrylate (EGDMA) as the cross-linking agent. The morphology and structure of the polymers were characterized using scanning electron microscopy (SEM), X-ray spectroscopy (XRD), Fourier-transform infrared spectroscopy (FT-IR), and Brunauer-Emmett-Teller (BET) specific surface area analysis. The adsorption performance for steroidal substances was also investigated. The results showed that the steroidal MIPs were uniformly-sized and well-dispersed spherical nanoparticles with porous surface. Adsorption performance results showed that MIPs had significantly stronger adsorption capacities for 5α-cholestane compared to NIP. Among the three MIPs, deoxycholic acid and β-sitosterol MIPs demonstrated stronger adsorption capacities for 5α-cholestane than that of cholesterol. The adsorption kinetics studies showed that the adsorption process of MIPs for 5α-cholestane was in accordance with the pseudo-second-order kinetic model, which was mainly controlled by chemisorption. The isothermal adsorption of both MIPs and NIP conformed to the Langmuir isothermal adsorption model and the Scatchard model, indicating that MIPs exhibited specific selective adsorption for 5α-cholestane and that the adsorption process was monolayer adsorption, with a maximum adsorption capacity of 0.735 mg/g. The study suggests that MIPs prepared with cholesterol, deoxycholic acid, and β-sitosterol as virtual templates have high molecular recognition and selectivity for 5α-cholestane.

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Four types of molecularly imprinted TiO 2 photocatalysts named MIP-TiO 2 /sulfadiazine (SD), MIP-TiO 2 /sulfamethoxazole (SMX), MIP-TiO 2 /sulfonamide (SN) and MIP-TiO 2 /aniline (AN), were synthesized. The five catalysts exhibited different degrees of selectivity for two types of sulfonamide antibiotics (SAs), SD and SMX. In the systems of NIP–TiO 2 , MIP-TiO 2 /SD, MIP-TiO 2 /SMX, MIP-TiO 2 /SN and MIP-TiO 2 /AN, the degradation rate constants of SD were 0.0789, 0.1031, 0.0859, 0.1034 and 0.1051 min−1, respectively. Moreover, the removal rate constants of SMX on the mentioned catalysts were 0.1076, 0.3250, 0.4260, 0.3885 and 0.5848 min−1, correspondingly. The single bond cleavage (C–S, C–N, and S–N bonds), hydroxylation, ring-opening, oxidation, and deamination were the major transformation pathways of SAs. With the presence of MIP-TiO 2 /SN and MIP-TiO 2 /AN, more low molecular weight products were generated, and the intermediates preferred to go through further hydroxylation and oxidation reactions. Therefore, besides MIP-TiO 2 /SD and MIP-TiO 2 /SMX, the novel MIP-TiO 2 /SN and MIP-TiO 2 /AN, which were prepared by using substances with the similar main functional groups as SAs as template molecules, had excellent catalytic abilities and less byproducts formed in the situation. The results may provide an effective idea to level up the SAs degradation rates, control the generation of intermediates, and reduce environmental risks. [Display omitted] • Four types of MIP-TiO 2 for SAs degradation were synthesized. • MIP-TiO 2 /AN had better catalytic ability than that of MIP-TiO 2 /SD and MIP-TiO 2 /SMX. • h+, O 2 ·− and e− were the major reactive species for the degradation of SAs. • Most byproducts went through the further hydroxylation and oxidation on MIP-TiO 2. [ABSTRACT FROM AUTHOR]

In this study, aluminophosphate molecular sieve AlPO 4 -11, with one-dimensional elliptical channels, was investigated under high pressure in non-penetrating silicone oil by X-ray powder diffraction, infrared spectroscopy and theoretical simulation, focusing on its intrinsic and template-modified mechanical behaviors. Two distinct compressible regimes were observed for both the calcined and as-synthesized AlPO 4 -11 frameworks before pressure-induced amorphization (PIA). The channel cross-section in the calcined AlPO 4 -11 framework showed an obvious increase in the ellipticity during this process. The framework structure began to lose crystallinity at approximately 2–3 GPa and underwent significant amorphization at 6.6 GPa. PIA was mainly induced via the destruction of the constructed species along the periodic crystallographic planes which are parallel to the channel axis. The bulk moduli showed that this empty framework was rather soft in these regimes. For the as-synthesized AlPO 4 -11 framework, the mechanical stability of the channels was markedly improved by the template molecules. A different elliptic deformation of the cross-section with a reduced contractility in the minor axis direction was presented. Discontinuous volume evolution occurs at 3–4 GPa and significant amorphization was postponed to 13.7 GPa. The as-synthesized AlPO 4 -11 was stiffer than calcined AlPO 4 -11 and showed a soft to hard transformation due to the strengthened host-guest interaction upon compression. Moreover, infrared spectra indirectly confirmed the structural collapses by detecting the vibrational characteristics of the embedded template molecules. The present results provided a comparative and basic knowledge of the intrinsic and extrinsic stability, compressibility, channel deformation and collapse of the AlPO 4 -11 framework under high pressure. This study emphasized the importance of guest molecules in modifying the mechanical behaviors of zeolites and resisting framework collapse. • Both the calcined and as-synthesized AlPO 4 -11 frameworks exhibit isostructural transformations under high pressure. • Two different compressible regimes are found before pressure-induced amorphization. • The template molecules strengthen the mechanical stability and modify the structural evolution of AlPO 4 -11. • The template molecules also function as local probes to detect the framework transformations in the infrared experiment. [ABSTRACT FROM AUTHOR]