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This article presents a simple and low-cost screening method based on optical microscopy and FT-IR spectroscopy for assessing microparticles found in rice. Five brands of rice packed in paper and foil bags from both the European Union (EU) and non-EU region were tested. Microparticles of various shapes have been found in the rice regardless of the packaging type and origin of the rice. The content of microparticles varies depending on the sample, from 2 to even 12 items per 1 g of rice. Overall, the abundance of microparticles is higher in the case of rice packed in foil bags. Not all identified microparticles are microplastics, but those that are microplastics cannot be directly linked to the composition of the rice package. For a cursory analysis aimed at distinguishing the infrared spectra of non-plastic microparticles (i.e. rice, paper or cellulose) from microplastics, it is sufficient only to analyse the absorption bands above 2800 cm -1 ., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Newly synthesized cerium oxide was successfully obtained by the hard templating route. The optimal As(III) and As(V) adsorption onto the studied adsorbent was reached for the initial pH of 4.0 and a contact time of 10 h. The highest static adsorption capacities for As(III) and As(V) were 92 mg g -1 and 66 mg g -1 , respectively. The pseudo-second-order model was well fitted to the As(III) and As(V) experimental kinetics data. The Langmuir model described the As(III) and As(V) adsorption isotherms on synthesized material. The adsorption mechanism of the studied ions onto the synthesized cerium oxide was complex and should be further investigated. The optimal solid-liquid ratio during the proposed aqueous extraction of inorganic As from the Fucus vesiculosus algae was 1:50. The optimal dosage of the synthesized cerium oxide (0.06 g L -1 ) was successfully applied for the first time for inorganic As removal from the aqueous algal extract.

Hypothesis: The negative pressure in liquids under the concave meniscus of nanometer size can be observed experimentally. This allows verification of the predictions of the macroscopic Young-Laplace law, which has so far been performed only on the basis of theoretical calculations. The deviation of the negative pressure from the Young-Laplace law allows to get information about the structure of the porous matrix., Experiments: The properties of n-heptane confined in nanometer-sized spaces are monitored in situ due to the particular ability of positronium to form subnanometer bubbles in liquids. Positron annihilation lifetime spectroscopy allows to detect their sizes, which in turn are used to determine surface tension and negative pressure of the investigated liquid. These results are obtained by means of an improved quantum-mechanical model approximating the o-Ps bubble with a 1.3 eV finite potential well., Findings: The dependence of the negative pressure on the curvature of the concave meniscus is found, which follows the Young-Laplace law with a good accuracy for model cylindrical pores. The differences between the pressure in the liquid confined in pores of various sizes and shapes in different materials allow inference about several phenomena (e.g. pore blocking in materials with a complex pore structure or swelling of the polymer)., (Copyright © 2019 Elsevier Inc. All rights reserved.)

This study presents an interesting and promising strategy for producing an oral multiparticulate formulation of the sustained-release of diclofenac sodium (DS) consisting of subunits closed inside hard gelatin capsules (each capsule contains ~50mg of diclofenac sodium). The subunits in the form of beads were produced through the encapsulation of diclofenac sodium dispersed within a nondisintegrating polymer carrier by a silica gel functionalized with the 3-aminopropyl groups. The hybrid silica gel, which plays the role of enteric coating, was fabricated by the gelation of the liquid silica precursors mixture (i.e. tetraethoxysilane (TEOS) and (3-aminopropyl)triethoxysilane (APTES)) in the vapor phase of ammonia. The conducted studies reveal that the introduction of the hybrid silica gel into the solid DS dispersion facilitates prolonged release in the neutral environment of the intestine. Since the ability of the multiparticulate formulation to control the release of the drug depends on the properties of its subunits, studies involving the low temperature N 2 sorption, DSC analysis together with spectroscopic techniques (XRD, SEM, 29 Si MAS NMR) were conducted., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The study discusses the synthesis of polymer-silica composites comprising water soluble drug (ibuprofen sodium, IBS). The polymers selected for this study were poly(TRIM) and poly(HEMA- co -TRIM) produced in the form of permanently porous beads via the suspension-emulsion polymerization method. The acid and base set ternary composites were prepared by the saturation of the solid dispersions of drug (poly(TRIM)-IBS and/or poly(HEMA- co -TRIM)-IBS) with TEOS, and followed by their exposition to the vapour mixture of water and ammonia, or water and hydrochloric acid, at autogenous pressure. The conducted analyses reveal that the internal structure and total porosity of the resulting composites strongly depend on the catalyst which was used for silica precursor gelation. The parameters characterizing the porosity of both of the acid set composites are much lower than the parameters of the base set composites. Moreover, the basic catalyst supplied in the vapour phase does not affect the ibuprofen sodium molecules, whereas the acid one causes transformation of the ibuprofen sodium into the sodium chloride and a derivative of propanoic acid, which is poorly water soluble. The release profiles of ibuprofen sodium from composites demonstrate that there are differences in the rate and efficiency of drug desorption from them. They are mainly affected by the chemical character of the polymeric carrier but are also associated with the restricted swelling of the composites in the buffer solution after precipitation of silica gel.

The adsorption and desorption of n-heptane on the mesoporous polymer resin Amberlite XAD4 were investigated in situ by positron annihilation lifetime spectroscopy (PALS). This technique allows the monitoring of porosity and subnanometer free volume changes as well as the amount of liquid adsorbate captured within an investigated sorbent, without causing any interference with the course of adsorption/desorption. In consequence, the conducted studies provide microscale insight into the sorption processes of n-heptane (which is a significant component of volatile organic compounds - VOCs) on the polymeric material. The total pore volume decreases parabolically with n-heptane pressure until it reaches zero just below the saturated vapor pressure. Simultaneously, the average pore size increases linearly until it has approximately doubled. However, much faster rates of change in both these parameters occur at relative pressures below 0.05. The PALS results can be properly explained only if the swelling of the polymer skeleton is taken into account during the alkane adsorption process. This is confirmed by long-term pumping, which was required to achieve stabilization of PAL spectra during the final phase of desorption. In addition, the evolution of subnanometer free volumes (located between polymer chains and formed in liquid n-heptane) support this interpretation of the results.

The present study concerns the preparation of ternary composites via the in situ encapsulation of solid dispersion of diclofenac sodium within the acrylic polymer beads. The encapsulating species were produced through the hydrolysis and condensation of the silica precursors (tetraethoxysilane or ethyltriethoxysilane) introduced into the solid dispersion. The transformation of precursors occurred in the vapor phase of ammonia. A great advantage of the presented vapor-phase method is preventing the desorption of the highly soluble drug during gelation of silica precursors, which stands in contrast to the conventional sol-gel processes occurring in the solution. The conducted studies, involving the low temperature N2 sorption together with spectroscopic techniques, provide insight into the structural differences of drug loaded particles. They reveal that the formation of silica gel accompanies the conversion of the drug into its amorphous form. Finally, the desorption profiles of diclofenac sodium demonstrate that the deposition of silica gel successfully diminishes the degree of the initial drug desorption while significantly modifying its release rate., (Copyright © 2016 Elsevier B.V. All rights reserved.)

Using a new synthesis technique, in which mesoporous Amberlite XAD7HP resin beads swollen with TEOS were exposed to vapors of either (H2O+HCl) or (H2O+NH3), we obtained smooth, porous, mechanically stable silica gel spheres after burning out the sacrificial organic template. Combined N2 sorption, SEM, TEM, (29)Si NMR, and Raman measurements were used to characterize the physical properties and molecular structures of the intermediate and final gels. Our atomically resolved TEM pictures provide the first visual demonstration of the presence of 3 to 6 member siloxane rings predicted by our Raman studies and other indirect methods. It is demonstrated that the physical appearance, morphology and porosity of the acid and base set gels are different from each other and also from those silica gels that were earlier polymerized from TEOS or Na-silicate saturated Amberlite XAD7HP with aqueous NH4OH or HCl solutions in liquid phase. We show that the different physical properties of the vapor-phase set gels are associated with different gelling rates at acidic and basic conditions, which generates molecular differences both in the intermediate and the final products., (Copyright © 2014 Elsevier Inc. All rights reserved.)

This study describes a novel approach to the synthesis of polymer-drug-silica nanocomposites via encapsulation/isolation of drug molecules, introduced into the polymer matrix by the silica gel. For the first time, tetraethoxysilane (TEOS) gelation in the vapor phase of the acidic catalyst is presented as an efficient method to enter the silica gel nanoparticles into the polymer-aspirin conjugate. The conducted studies reveal that the internal structure of the polymer carrier is significantly reorganized after the embedding of aspirin molecules and the silica gel. The total porosity of the polymer-drug-silica nanocomposites and the molecular structure of the silica gel embedded in the system strongly depend on the conditions of the silica source transformation. Additionally, the release of the drug was fine-tuned by adapting the conditions of hydrolysis and condensation of the silica gel precursor. Finally, to prove the usefulness of the proposed synthesis, the controlled release of aspirin from the polymer-drug-silica nanocomposites is demonstrated.

Polymer (XAD7HP)/Ti 4+ nanocomposites were prepared through the swelling of polymer in titanium (IV) ethoxide as a titanium dioxide precursor. The nanocomposite beads exhibit relatively high porosity different than the porosity of the initial polymer. Thermal treatment of composite particles up to 200 °C in vacuum causes the change of their internal structure. At higher temperature, the components of composite become more tightly packed. Calcination at 600 °C and total removal of polymer produce spherically shaped TiO 2 condensed phase as determined by XRD. Thermally treated composites show the substantial change of pore dimensions within micro- and mesopores. The presence of micropores and their transformation during thermal processing was studied successfully by positron annihilation lifetime spectroscopy (PALS). The results derived from PALS experiment were compared with those obtaining from low-temperature nitrogen adsorption data.

The swelling of poly(TRIM) spherical particles in TEOS is assessed as a potential way for obtaining polymer-silica nanocomposite materials. Silica deposition was achieved by simply stirring of swollen polymer particles in acidic hydrochloric-water solution. This procedure leads to spherical composite particles with dispersed silica gel within the polymer matrix. The resulting material exhibits the same morphology as the initial polymer. Nanocomposite particles are silica rich (about 17 wt.%). Characterization of the nanocomposites was performed using scanning electron microscopy, FT-IR spectroscopy, (29)Si CP MAS NMR spectroscopy and thermogravimetry. Moreover, the use of positron annihilation lifetime spectroscopy PALS to characterize the structural properties of the nanocomposites is presented. This technique gave more realistic pieces of information about the pore structure of the investigated samples in contrast to nitrogen adsorption studies., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Monodisperse polymer/silica composite material with a polymer as the core and hydrophilic silica gel as the shell was prepared by a two-stage procedure. In the first stage, the swelling of Amberlite XAD7HP particles in tetraethoxysilane (TEOS) was performed. Subsequently a portion of the XAD7HP particles impregnated with TEOS were transferred to acidic aqueous solution to facilitate a sol-gel process of the silica precursor. This procedure is assessed as a potential route to a composite material with a core-shell morphology. Scanning electron microscopy and (29)Si MAS NMR indicated the formation of silica microfibers on polymer beads. The silica microfibers were anchored in the polymer matrix. In consequence, the silica shell exhibited relatively high mechanical stability. The swelling of the polymer and the formation of the silica phase substantially changed the porosity of the initial polymer material. The final composite surprisingly exhibited very homogeneous porosity. The textural characteristics of the investigated materials were defined by nitrogen adsorption-desorption at 77K., (Copyright 2010 Elsevier Inc. All rights reserved.)