Preparation of Polystyrene Microsphere-Templated Porous Monolith for Wastewater Filtration

Porous monoliths prepared using templates are highly sought after for filtration applications due to their good mass transport properties and high permeability. Current templates, however, often lead to the formation of dead-end pores and irregular pore distributions, which reduce the efficiency of the substrate flow across the monolith column. This study focused on the preparation of a microsphere-templated porous monolith for wastewater filtration. The optimal template/monomer ratio (50:50, 60:40, 70:30) was determined, and appropriate template removal techniques were assessed for the formation of homogenous pores. The physicochemical characteristics and pore homogeneity of the monoliths were examined. The 60:40 ratio was determined to result in monoliths with homogeneous pore distributions ranging from 1.9 μm to 2.3 μm. SEM and FTIR investigations revealed that solvent treatment was effective for removing templates from the resulting solid monolith. The water quality assessments revealed reductions in the turbidity and the total number of suspended particles in the tested wastewater of up to 96–99%. The findings of this study provide insightful knowledge regarding the fabrication of monoliths with homogenous pores that are beneficial for wastewater treatment.

Mesoporous Carbon Production by Nanocasting Technique Using Boehmite as a Template

A series of mesoporous carbonaceous materials were synthesized by the nanocasting technique using boehmite as a template and glucose as a carbon precursor. After pyrolysis and template removal, the resulting material is a mesoporous carbon that can be additionally doped with N, B and K during prepyrolysis impregnation. In addition, the influence of doping on the morphology, crystallinity and stability of the synthesized carbons was studied using X-ray diffraction, nitrogen physisorption, thermogravimetry, Raman and IR spectroscopy and transmission electron microscopy. While the nanocasting process is effective for the formation of mesopores, KOH and urea do not modify the textural properties of carbon. The use of H3PO4 as a dopant, however, led to the formation of an AlPO4 compound and resulted in a solid with a lower specific surface area and higher microporosity. All doped solids present higher thermal stability as a positive effect of the introduction of heteroatoms to the carbon skeleton. The phosphorus-doped sample has better oxidation resistance, with a combustion temperature 120–150 °C higher than those observed for the other materials.

Preparation of Al-Containing ZSM-58 Zeolite Membranes Using Rapid Thermal Processing for CO2/CH4 Mixture Separation

The synthesis of DDR-type zeolite membranes faces the problem of cracks that occur on the zeolite membrane due to differences in the thermal expansion coefficient between zeolite and the porous substrate during the detemplating process. In this study, Al-containing ZSM-58 zeolite membranes with DDR topology were prepared by rapid thermal processing (RTP), with the aim of developing a reproducible method for preparing DDR zeolite membrane without cracks. Moreover, we verified the influence of RTP before performing conventional thermal calcination (CTC) on ZSM-58 membranes with various silica-to-aluminum (Si/Al) molar ratios. Using the developed method, an Al-containing ZSM-58 membrane without cracks was obtained, along with complete template removal by RTP, and it had higher CO2/CH4 selectivity. An all-silica ZSM-58 membrane without cracks was obtained by only using the ozone detemplating method. ZSM-58 crystals and membranes with various Si/Al molar ratios were analyzed by using Fourier-transform infrared (FTIR) spectroscopy to confirm the effects of RTP treatment. Al-containing ZSM-58 zeolites had higher silanol concentrations than all-silica zeolites, confirming many silanol condensations by RTP. The condensation of silanol forms results in the formation of siloxane bonds and stronger resistance to thermal stress; therefore, RTP caused crack suppression in Al-containing ZSM-58 membranes. The results demonstrate that Al-containing ZSM-58 zeolite membranes with high CO2 permeance and CO2/CH4 selectivity and minimal cracking can be produced by using RTP.

Invisalign® vs. Spark™ Template: Which Is the Most Effective in the Attachment Bonding Procedure? A Randomized Controlled Trial

Aim: The primary aim of this randomized clinical trial was to evaluate the percentage of attachments’ debonding at the template’s removal both in Invisalign® and Spark™ systems. The secondary aim was to define the percentage of patients who did not show attachments’ debonding at the template’s removal. Materials and methods: Eighty patients who needed an orthodontic treatment were included in the study and randomly assigned to a treatment to be performed with Spark™ or Invisalign® clear aligners system. The patients were equally divided into two groups: Spark group (n = 40) and Invisalign group (n = 40). At the template removal by the teeth surface after the attachment bonding procedure, in each patient of both groups, it was assessed if some attachment debonding occurred and the number of attachments detached. Results: The Spark group showed, in general, a lower frequency in debonding in comparison with the Invisalign group, as 87.5% of patients in the Spark group did not show any bonding failure versus 27.5% in those of the Invisalign group. Conclusions: At template removal, the Spark™ template showed less attachment debonding compared to the Invisalign® template. The Spark™ template can be considered more effective in attachments’ transferring to the tooth surface than the Invisalign® one.

Rational Design and Fabrication of Biomimetic Hierarchical Scaffolds With Bone-Matchable Strength for Bone Regeneration

The development of scaffolds with bone-mimicking compositions, hierarchical structure, and bone-matchable mechanical properties may offer a novel route for the achievement of effective bone regeneration. Although bioactive glasses have been widely utilized for bone regeneration at the clinical level, their brittleness and uncontrolled pore structure limit further applications. Herein, this study aims to develop a kind of bioactive scaffold with a macroporous/microporous/mesoporous structure via impregnating a sponge template with mesoporous bioactive glass (MBG) sol, followed by sponge template removal. In order to improve the mechanical properties and stability of the MBG scaffolds, desaminotyrosyl ethyl tyrosine polycarbonates (PDTEC), a biodegradable polymer which does not induce acid side-effects caused by conventional polylactide, was selected to decorate the resulting hierarchical scaffolds through a surface coating approach. The PDTEC functionalization endowed the scaffolds with improved mechanical strength matching the bearable range of trabecular bone (2–12 MPa). Meanwhile, the relative neutral pH value was maintained during their degradation process. In vitro studies demonstrated that the PDTEC accelerated the biomineralization of the scaffolds, and promoted the attachment and proliferation, holding high promise for bone regeneration.

Tamoxifen Delivery System Based on PEGylated Magnetic MCM-41 Silica

Magnetic iron oxide containing MCM-41 silica (MM) with ~300 nm particle size was developed. The MM material before or after template removal was modified with NH2- or COOH-groups and then grafted with PEG chains. The anticancer drug tamoxifen was loaded into the organic groups’ modified and PEGylated nanoparticles by an incipient wetness impregnation procedure. The amount of loaded drug and the release properties depend on whether modification of the nanoparticles was performed before or after the template removal step. The parent and drug-loaded samples were characterized by XRD, N2 physisorption, thermal gravimetric analysis, and ATR FT-IR spectroscopy. ATR FT-IR spectroscopic data and density functional theory (DFT) calculations supported the interaction between the mesoporous silica surface and tamoxifen molecules and pointed out that the drug molecule interacts more strongly with the silicate surface terminated by silanol groups than with the surface modified with carboxyl groups. A sustained tamoxifen release profile was obtained by an in vitro experiment at pH = 7.0 for the PEGylated formulation modified by COOH groups after the template removal. Free drug and formulated tamoxifen samples were further investigated for antiproliferative activity against MCF-7 cells.