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The random lamellae of the synthetic CP were synthesized with a hydrothermal approach using o-Phenylenediamine (OPD) as a modifier. The decreases in the order degree of the CP synthesized in the presence of the OPD resulted from the loss of long-range order in a certain direction. Subsequently, the ultrasonic treatment and washing were conducive to further facilitate the disordered arrangements of its lamellae. The possible promotion mechanism regarding the nucleation and growth behaviors of the sol-gel particles was proposed. The fractal evolutions of the aluminosilicate species with crystallization time implied that the aluminosilicate species became gradually smooth to rough during the crystallization procedures since the amorphous structures transformed into flower-like morphologies. Their gas adsorption and separation performances indicated that the adsorption capacity of CO2 at 273 K reached up to 2.14 mmol·g−1 at 1 bar, and the selective factor (CO2/CH4) up to 3.4, much higher than that of the CPs synthesized without additive OPD. The breakthrough experiments displayed a longer breakthrough time and enhancement of CO2 uptake, showing better performance for CO2/CH4 separation. The cycling test further highlighted their efficiency for CO2/CH4 separation. [ABSTRACT FROM AUTHOR]

Various cation–exchanged clinoptilolites (M–CPs, M = Li+, Cs+, Ca2+, Sr2+) were prepared, and their exchanged thermodynamic (and kinetic) properties and adsorption performances for CH4, N2, and CO2 were investigated. The results demonstrated that the relative crystallinity of M–CPS decreased with the increase of exchange times. Their chemisorbed water weight loss gradually increased with the increasing exchange times, except that of Cs–x–CP. The Δr G m θ values of exchange process of Li+, Cs+, Ca2+, or Sr2 presented the increased trend with the enhanced exchange times, but they decreased as the temperature increased. The negative Δr G m θ values and the positive Δr H m θ and Δr S m θ values suggested that the exchanged procedure belonged to spontaneous, endothermic, and entropy-increasing behaviors; their kinetic performances followed a pseudo–second–order model. However, the calculated Ea values of exchange process showed the increased tendencies with the enhanced exchange times, indicating that the exchange process became more difficult. Finally, the preliminary adsorption results indicated that the maximum adsorption amount at 273 K and 1 bar was 0.51 mmol/g of CH4 and 0.38 mmol/g of N2 by (Na, K)–CP, and 2.32 mmol/g of CO2 by Li–6–CP. [ABSTRACT FROM AUTHOR]

Titanates are frequently used as precursors to prepare transesterification catalysts with TiIV species. Unfortunately, it is challenging to control the dispersity of TiIV active sites on supports. Herein, a series of TiIV species is anchored on abundant linker vacancy sites by introducing point and large scale defects in UiO-66(Zr/Ti) with hierarchical-pore structure. The catalyst functionalized by titanium(IV) oxide bis(2,4-pentanedionate) shows excellent catalytic performance in the transesterification of dimethyl carbonate with phenyl acetate. The catalysts are characterized by XRD, FT-IR, N2 adsorption–desorption, XPS, SEM and STEM-HAADF techniques. The results demonstrate that the delicate mesopores in the support can not only exhibit a large surface area for the distribution of the active sites, but also provide better mass transfer performance. Meanwhile, the introduction of octahedral TiIV ions raises the activity of the catalyst via more coordinatively unsaturated ZrIV sites. Furthermore, using titanium(IV) oxide bis(2,4-pentanedionate) as a Ti source can effectively prevent the condensation of tetrahedral TiIV species anchored on the hierarchical-pore UiO-66(Zr/Ti) support. [ABSTRACT FROM AUTHOR]

The catalysts containing tetra-coordinated titanium have been widely used for transesterification. The key issue in the design of these catalysts is the stability of tetra-coordinated titanium. In this study, mesoporous amorphous titanium oxides coated on a zeolitic imidazolate framework (ZIF-8) were developed by using a hexadecylamine (HDA) surfactant as a structure-directing agent. The mesopores surface areas of the amorphous TiO2 shell could be simply controlled by changing the dosage of HDA in the synthetic process. The novel, efficient and recyclable heterogeneous catalyst was introduced to the synthesis of diphenyl carbonate from dimethyl carbonate and phenyl acetate for the first time. The catalyst structure was characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, nitrogen adsorption–desorption, Fourier transform infrared spectroscopy and thermogravimetric analysis. The effects of the molar ratio of Ti to Zn, HDA amount, catalyst amount, reaction time and reusability on the yield of the transesterification products were also determined. The results showed that the mesopores of TiO2 shell facilitated reactants and productions diffusion to increase the conversion of phenyl acetate and yield of diphenyl carbonate. Moreover, the coordination between titanium and ZIF-8 also endowed the catalysts with reasonable reusability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nonionic surfactant-assisted strategy for UiO-66-on-clinoptilolite was proposed. • MOF particle located on facet exposures of CP lamellas was controlled by PEG and PVP. • UiO-66-NH 2 -on-CP hybrid exhibited an excellent separation performance for CO 2 and CH 4. The constructed strategy of the disorderly layered UiO-66-on-clinoptilolite heterostructures was proposed through assistance of polyethylene glycol (PEG) and polyvinylpyrrolidone (PVP). Their physicochemical properties were demonstrated via various characterizations, such as X-ray powder diffraction (XRD) patterns and scanning/transmission electron microscope (SEM/TEM) images. Particularly, the small‑angle X‑ray scattering (SAXS) method was employed to elucidate their fractal structure evolutions, manifesting the transformations of surface fractal with irregularity and roughness. The results showed that the PEG introduction was beneficial to the formation of disorderly layered clinoptilolites (CP). The particles sizes of UiO-66-NH 2 were successfully controlled via additive PVP, and the interactions between UiO-66-NH 2 and deposited CP-PEG were enhanced. The preliminarily adsorption performances of the obtained UiO-66-on-CPs exhibited a superior selective factor (around 26) of CO 2 /CH 4. This approach may open a new avenue to improve its adsorption selective performance for CO 2 and CH 4 due to its dual microporous features and enlarged lamellar spacing. [ABSTRACT FROM AUTHOR]

Developing effective intelligent nanocarriers is highly desirable for fluorescence imaging and therapeutic applications but remains challenging. Using a vinyl-grafted BMMs (bimodal mesoporous SiO2 materials) as a core and PAN ((2-aminoethyl)-6-(dimethylamino)-1H-benzo[de]isoquinoline-1,3(2H)-dione))-dispersed dual pH/thermal-sensitive poly(N-isopropylacrylamide-co-acrylic acid) as a shell, PAN@BMMs with strong fluorescence and good dispersibility were prepared. Their mesoporous features and physicochemical properties were extensively characterized via XRD patterns, N2 adsorption–desorption analysis, SEM/TEM images, TGA profiles, and FT-IR spectra. In particular, their mass fractal dimension (dm) features based on SAXS patterns combined with fluorescence spectra were successfully obtained to evaluate the uniformity of the fluorescence dispersions, showing that the dm values increased from 2.49 to 2.70 with an increase of the AN-additive amount from 0.05 to 1%, along with the red shifting of their fluorescent emission wavelength from 471 to 488 nm. The composite (PAN@BMMs-I-0.1) presented a densification trend and a slight decrease in peak (490 nm) intensity during the shrinking process. Its fluorescent decay profiles confirmed two fluorescence lifetimes of 3.59 and 10.62 ns. The low cytotoxicity obtained via in vitro cell survival assay and the efficient green imaging performed via HeLa cell internalization suggested that the smart PAN@BMM composites are potential carriers for in vivo imaging and therapy. [ABSTRACT FROM AUTHOR]

[Display omitted] • P(NIPAM-co-AA) copolymer with dual temperature/pH- responsive property was prepared. • Structural irregularity and surface roughness of copolymer were evaluated via SAXS data. • IBU-releasing mechanism from P(NIPAM-co-AA) was proposed from fractal perspective. • Fractal evolutions of P(NIPAM-co-AA) were elucidated in the drug delivery process. Using acrylic acid (AA) as pH-responsive monomer, and N-isopropyl acrylamide (NIPAM) as temperature-responsive monomer, the stimuli-responsive P(NIPAM- co -AA) copolymers were prepared via soap-free emulsion polymerization. Their constructed porous structures, swelling-shrinking behaviors, and controlled drug delivery performances were systematically demonstrated via various characterizations. Particularly, the small-angle X-ray scattering (SAXS) method was employed to elucidate their fractal features and the structural evolutions with increasing AA content, showing the occurrences from dense aggregates (mass fractal (D m) value of 2.92) to loose networks (surface fractal (D s) value of 2.18) with statistical self-similarity. Meanwhile, the ibuprofen (IBU) was used as a model drug, their temperature/pH-dual sensitive delivery and related mechanism were discussed on the basis of the fractal demonstrations. The results showed that the cross-linking networks with an interconnected open-cell skeleton and abundant large pores were beneficial to improve the adsorption-diffusion performances of the drug delivery, while the drug-releasing kinetics of P(NIPAM- co -AA)-30 followed a non-Fickian diffusion mechanism. Specially, the fractal evolutions of the obtained copolymers along with the drug loading and releasing behaviors were evaluated via SAXS patterns. In which, the drug-loaded copolymers presented the D s characteristics with the increased amounts of monomer AA added. While, the fractal features varied from D s value of 2.40 to D m value of 2.76 along with sustained drug releasing in pH 2.0 at 25 °C, indicating that the structural transformation of the used copolymers occurred from dense (D m value of 2.86) to loose (D m value of 2.76) with the extension of release time. These demonstrations suggested that the resultant P(NIPAM- co -AA) hydrogel is a potential intelligent-responsive drug carrier for targeted delivery. [ABSTRACT FROM AUTHOR]

Clinoptilolite (CP) with various morphologies, such as spherical, flower, cylindrical, and disc-shape, were successfully synthesized in the presence of alcohol solvents with different carbon chain lengths. The structural and textural properties of the resultant CPs were characterized via XRD, SEM, TG-DSC profiles, TEM, NMR, FT-IR spectra, and N 2 sorption isotherms. The effect of the additive amount of various alcohol solvents on the induction (nucleation) periods and growth stages of synthetic CPs were detailed investigated. Their activation energies of induction (E n) and growth (E g) periods during crystallization intervals were calculated according to the Arrhenius equation, where the former being larger than the latter, indicating that nucleation is the key step during the whole synthesis of CPs. Particularly, the E n value gradually increased as the increasing chain-length of the used alcohol, but smaller than that without additive alcohols. These demonstrations implied that the presence of alcohol solvents is beneficial to promote the nucleation process of synthetic CP. Furthermore, their CH 4 and N 2 adsorption capacity and selectivity were preliminary explored, showing the highest selective factor of 5.58 at 0 °C for CH 4 /N 2 separation using flower-like CP as an adsorbent. These results suggested a promising adsorbent for wide applications in gas separation. [Display omitted] • Alcohol-modified hydrothermal method for synthesis of clinoptilolite was proposed. • Influence of aliphatic alcohols on morphology of clinoptilolites was explored. • Crystalline kinetic for induction and growth stage in clinoptilolite was studied. • Application of synthetic clinoptilolite in CH 4 /N 2 separation was investigated. [ABSTRACT FROM AUTHOR]