Quaternization of Poly(2-diethyl aminoethyl methacrylate) Brush-Grafted Magnetic Mesoporous Nanoparticles Using 2-Iodoethanol for Removing Anionic Dyes

Smart pillar[5]arene-based PDMAEMA/PES beads for selective dye pollutants removal: design, synthesis, chemical-physical characterization, and adsorption kinetic studies

This article reports on the synthesis of an innovative smart polymer, P5-QPDMAEMA, opportunely developed with the aim of combining the responsiveness of PDMAEMA polymer and the host-guest properties of covalently linked pillar[5]arenes. Thanks to a traditional Non-Induced Phase Separation (NIPS) process performed at various coagulation pH, the blending of P5-QPDMAEMA with polyethersulfone gave rise to the formation of functional beads for the removal of organic dyes in water. Adsorption tests are carried out on all the produced blend-based beads by employing two representative dyes, the cationic methylene blue (MB), and the anionic methyl orange (MO). In particular, the P5-QPDMAEMA based beads, prepared at acidic pH, featured the best MO removal rate (i. e., 91.3 % after 150 minutes starting from a 20 mg ⋅ L-1 solution) and a high selectivity towards the removal of the selected anionic dye. Based on the adsorption kinetics and isotherm calculations, the pseudo-first order and Freundlich models were shown to be the most suitable to describe the MO adsorption behavior, achieving a maximum adsorption capacity of 21.54 mg ⋅ g-1. Furthermore, zwitterionic beads are obtained by a post-functionalization of the PDMAEMA and the P5-QPDMAEMA based beads, to test their removal capability towards both anionic and cationic dyes, as shown.

Fabrication of carboxylic functionalized poly(methacrylic acid 2-(tert-butylamino)ethyl ester)-coated mesoporous silica nanoparticles and their application for removing ionic dyes from polluted water

The removal of dyes from wastewater that are released during industrial processes has become a significant concern in the environmental science in recent years. To tackle this issue, researchers are exploring the use of nanomaterials for designing new adsorbents. Another promising approach is to grow polymer brushes with high density functional groups via surface-initiated atom transfer radical polymerization (SI-ATRP), which can significantly enhance their ability to absorb dyes. The presence of carboxylic acid groups on the adsorbent material significantly contributes to its efficacy in dye removal by enhancing adsorption capacity, enabling selective adsorption, pH-dependent behavior, chelation, or complexation, and providing stability for repeated usage. In this work, a nanomaterial of carboxylic functionalized poly (methacrylic acid 2-(tert-butylamino)ethyl ester)-coated mesoporous silica nanoparticles (MSNPs-PMATBAE-COOH) was synthesized by the growth of PTBAEMA via surface-initiated atom-transfer radical polymerization, then reacted with succinic anhydride reaction. The chemical structure of MSNPs-PMATBAE-COOH was confirmed using multiple methods, including FT-IR and DLS, and the core-brush morphology was observed clearly using TEM. MSNPs-PMATBAE-COOH were subsequently employed to adsorb hazardous dyes efficiently. The anionic polymer brushes enabled the adsorption of methylene blue (MB) and tetraethylrhodamine (TER) at optimum pH value of 3. The results also indicated that MSNPs-PMATBAE-COOH possessed significant adsorption capacity (263.4 and 212.9 mg g-1 for MB and TER, respectively) and fast adsorption rate (within 15 min), which can be explained by the abundance of adsorptive polymer brushes and the small size of the nanoparticles. Overall, the findings indicate that MSNPs-PMATBAE-COOH is a highly effective adsorbent material for eliminating dye pollutants from wastewater.

Hybrid Polymer-Silica Nanostructured Materials for Environmental Remediation

Due to the ever-growing global population, it is necessary to develop highly effective processes that minimize the impact of human activities and consumption on the environment. The levels of organic and inorganic contaminants have rapidly increased in recent years, posing a threat to ecosystems. Removing these toxic pollutants from the environment is a challenging task that requires physical, chemical, and biological methods. An effective solution involves the use of novel engineered materials, such as silica-based nanostructured materials, which exhibit a high removal capacity for various pollutants. The starting materials are also thermally and mechanically stable, allowing for easy design and development at the nanoscale through versatile functionalization procedures, enabling their effective use in pollutant capture. However, improvements concerning mechanical properties or applicability for repeated cycles may be required to refine their structural features. This review focuses on hybrid/composite polymer-silica nanostructured materials. The state of the art in nanomaterial synthesis, different techniques of functionalization, and polymer grafting are described. Furthermore, it explores the application of polymer-modified nanostructured materials for the capture of heavy metals, dyes, hydrocarbons and petroleum derivatives, drugs, and other organic compounds. The paper concludes by offering recommendations for future research aimed at advancing the application of polymer-silica nanostructured materials in the efficiency of pollutant uptake.

Effect of Kaolin Clay and ZnO-Nanoparticles on the Radiation Shielding Properties of Epoxy Resin Composites

The use of radiation is mandatory in modern life, but the harms of radiation cannot be avoided. To minimize the effect of radiation, protection is required for the safety of the environment and human life. Hence, inventing a better shield than a conventional shielding material is the priority of researchers. Due to this reason, this current research deals with an innovative shielding material named EKZ samples having a composition of (epoxy resin (90-40) wt %-kaolin clay (10-25) wt %-ZnO-nano particles (0-35) wt %). The numerous compositional variations of (epoxy resin, kaolin clay, and ZnO-nano particles on the prepared EKZ samples varied the density of the samples from 1.24 to 1.95 g/cm³. The radiation shielding parameter of linear attenuation coefficient (LAC), half value layer (HVL), tenth value layer (TVL), and radiation protection efficiency (RPE) were measured to evaluate the radiation diffusion efficiency of newly made EKZ samples. These radiation shielding parameters were measured with the help of the HPGe detector utilizing the three-point sources (Am-241, Cs-137, and Co-60). The obtained results exposed that the value of linear attenuation coefficient (LAC) and radiation protection efficiency (RPE) was maximum, yet the value of half value layer (HVL), and tenth value layer (TVL), were minimum due to the greater amount of kaolin clay and ZnO-nanoparticles, whereas the amount of epoxy resin was lesser. In addition, it has been clear that as-prepared EKZ samples are suitable for low-dose shielding applications as well as EKZ-35 showed a better shielding ability.

High-Efficient Anionic Dyes Removal from Water by Cationic Polymer Brush Functionalized Magnetic Mesoporous Silica Nanoparticles

High efficiency removal of methyl orange (MO) and bromothymol blue (BT) dyes from contaminated water has been reported using magnetic mesoporous nanoparticles modified with cationic polymer brush (poly(2-methacryloyloxy)ethyl] trimethylammonium chloride solution) (Fe3O4-MSNs-PMETAC). Atom transfer radical polymerization (ATRP) was utilized to grow the polymer chains on the magnetic mesoporous silica nanoparticles. The chemical surface modifications were confirmed using IR, TGA, SEM and TEM. The results show that the obtained Fe3O4-MSNs-PMETAC materials were nearly spherical in shape with approximately 30 nm magnetic core, and silica shell thicknesses ranged from 135 to 250 nm. The adsorption performance of the material was found to be unaffected by the pH (3-9) of the media, with a removal efficiency of 100% for both dyes. The adsorption of BT and MO on the surface of Fe3O4-MSNs-PMETAC was found to follow Freundlich and Langmuir models, respectively. Since the synthesized nanocomposite materials exhibit an enhanced properties such as large maximum adsorption capacity, rapid synthesis process, and easy separation from solution, it could be an effective sorbent for the removal of other pollutants such as potentially toxic anionic elements (e.g., arsenate and chromate ions) from water and wastewater.

Efficient Removal of Dyes from Aqueous Solution by Adsorption on L-Arginine-Modified Mesoporous Silica Nanoparticles

The use of mesoporous silica modified with L-arginine (Ar-MSNPs) for the removal of ionic dyes from aqueous solutions has been investigated. Several analytical techniques have been used to determine the characteristics of nanoadsorbents. The removal of crystal violet and fluorescein was performed using the batch method to investigate the effects of cultivation pH, initial concentrations of dyes, and exposure time on adsorption efficiency. The optimum adsorption of fluorescein was achieved at pH 2, whereas the optimum adsorption of crystal violet was achieved at pH 13. The equilibrium was established in both systems at 20 min at low concentrations, and approximately 30 min at high concentrations. The equilibrium adsorption data was analyzed using Langmuir and Freundlich isotherm models. The correlation coefficient (R2) values of the isotherms presented the best fit with the Langmuir isotherm. The adsorption kinetic data was fitted with the pseudo second-order model for both systems.

Aspartic Acid- and Glycine-Functionalized Mesoporous Silica as an Effective Adsorbent to Remove Methylene Blue from Contaminated Water

In this work, aspartic acid- and glycine-functionalized mesoporous silica nanoparticles (Asp-MSNs and Gly-MSNs) were successfully prepared and applied as adsorbents for removal of methylene blue (MB) from contaminated water. The mesoporous structure of the fabricated nanomaterials was confirmed by nitrogen adsorption/desorption with specific surface area of ca. 700 m2/g and pore volume of 0.9 cm3/g for both Asp-MSNs and Gly-MSNs. The average size of the nanoadsorbents was estimated to be ca. 290 nm as characterized by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The physical and chemical properties of the Asp-MSNs and Gly-MSNs were also characterized by Fourier transform infrared (FTIR) spectroscopy, zeta potential, and elemental analysis. Asp-MSNs and Gly-MSNs exhibited good adsorption performance for removal of cationic organic dyes (MB). The equilibrium adsorption capacity of Asp-MSNs and Gly-MSNs was found to be 55 mg·g−1 and 43 mg·g−1, respectively, under the optimal conditions. The Langmuir model and pseudo-second-order equation exhibited good correlation with the isotherm and adsorption kinetic data for MB, respectively.

Highly Efficient and Rapid Removal of Methylene Blue from Aqueous Solution Using Folic Acid-Conjugated Dendritic Mesoporous Silica Nanoparticles

Dendritic Mesoporous Silica Nanoparticles (DMSNs) are considered superior in the adsorption of unfavorable chemical compounds and biological pollutants. Herein, we have synthesized folic acid-terminated dendritic mesoporous silica nanoparticles (FA-DMSN) for the removal of cationic dyes, methylene blue (MB), from aqueous solutions. The structural, morphological, functional, specific surface area, pore size distribution, and thermal properties of the synthesized DMSNs were identified using a scanning electron microscope (SEM), a transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), Brunauer−Emmett−Teller (BET), and Thermogravimetric Analyzer (TGA). The synthesized DMSNs exhibited a high surface area (521 m2 −1) and pore volume (1.2 cm3 g−1). In addition, it features both wide pore size and narrow distributions, which strongly affect the adsorption performance in terms of the equilibrium uptake time. Moreover, the impact of pH, contacting time, and dye’s initial concentration on the removal efficiency of MB was studied. The extraction efficiency of FA-DMSN was found to be three times more effective than the bare DMSN materials. Langmuir isotherm fitted the experimental data very well with a correlation coefficient value of 0.99. According to the Langmuir model, the maximum adsorption capacity was 90.7 mg/g. Furthermore, the intra−particle diffusion model revealed a significantly fast intra-particle diffusion which can be attributed to the presence of the large pore’s channels. Finally, the fast adsorption of MB molecules, reaching their equilibrium capacity within tens of seconds, as well as the low cost and ease of FA-DMSN fabrication, makes the developed material an effective adsorbent for water remediations.