Rahman Hosseinzadeh

A titanium dioxide (TiO ₂ )‐based polymeric nanocomposite incorporating a carbazole‐aniline copolymer (poly(Ani‐co‐Cz)) was synthesized for sunlight‐driven photocatalytic water remediation using methylene blue (MB) as a model organic pollutant, and its antibacterial activity was also evaluated. The TiO ₂ /Poly(Ani‐co‐Cz) nanocomposite was characterized, revealing a band gap energy (Eg) of 3.06 eV, calculated using Tauc's equation. Under natural solar irradiation, the nanocomposite with an optimal TiO ₂ /Poly(Ani‐co‐Cz) ratio of 5 achieves up to 99% MB degradation, exceeding pristine TiO ₂ by over 33%. This improvement is attributed to enhanced charge separation and light absorption induced by the conductive copolymer. Photocatalysis kinetics were evaluated using the Langmuir–Hinshelwood model, and potential mechanisms were examined through hydroxyl radical trapping experiments. The pseudo‐first‐order rate constant (k _app ) for MB photodegradation was found to be 0.0301 min ⁻¹ , indicating strong compatibility with pseudo‐first‐order kinetics. The study confirms the generation of hydroxyl (OH ^• ) and superoxide (O ₂ ^•− ) radicals during dye degradation by the nanocomposite. Antibacterial testing revealed strong inhibition against Bacillus subtilis , a moderate effect against Staphylococcus aureus , minimal impact against Escherichia coli , and a negligible effect against Pseudomonas aeruginosa . These findings indicate that the TiO ₂ /poly(Ani‐co‐Cz) nanocomposite is a promising dual‐function material for solar‐driven, sustainable water treatment, enabling simultaneous photocatalytic pollutant removal and antibacterial action.

In this study, we report the synthesis of a novel magnetic nanocomposite, Fe₃O₄@SiO₂@MgAl-LDH@Au, as an efficient and environmentally ben

Plastic products are essential materials that play critical roles in people's lives in the modern world. However, plastic pollution is a growing global challenge due to the fact that its durability and long life span make it a persistent problem. In the present study, we aimed to analyze the contamination of meso- and microplastics (MPs) through separation based on density differences in sediments from the southern coasts of Caspian Sea. We found that the plastic contents of meso- and MPs were 14-38 and 100-286 particles kg−1 dry weight (dw) sediments, respectively. The size of debris was detected in the range of 0.1-15 mm. The relationship between meso- and MPs, the distance to coastline was investigated. In general, there was no correlation between distance to coastline and the concentration of meso- and MPs in the sediments from the southern coast. The plastic particles had a high variety of colors, but they were mainly transparent, black and gray, respectively. Polyethylene (PE), polyamide (PA), polyethylene terephthalate (PET), polystyrene (PS), polypropylene (PP), polyurethane (PU), and polyacrylonitrile (PAN) were identified in the samples using FTIR analysis. Contrary to previous reports, more meso- and MPs were found in the west and east coasts sediment samples from the southern Caspian Sea basin. Our findings suggest that environmental conditions may play a more important role in the accumulation and distribution of MPs along the coasts of Iran. These findings provide new information to evaluate the environmental effects of MPs in future research.

In this study, deep eutectic solvents were attached to SiO₂-coated magnetic nanoparticles through a linker. The resulting nanomagnet-immobilized arginine/choline chloride designated as MNP@Arg/ChCl was characterized using FT-IR, XRD, TGA, VSM, and SEM techniques. The catalyst showed an irregular spherical morphology, and the mean particle diameter was determined to be about 39.9 nm. TGA analysis also confirmed that the catalyst remained thermally stable up to approximately 225 °C. MNP@Arg/ChCl demonstrated excellent catalytic activity in the solvent-free synthesis of 2,3-disubstituted-2,3-dihydroquinazolin-4(1 H)-one derivatives via a three-component reaction involving isatoic anhydride, amines, and aldehydes. The scope of this method was assessed using various aromatic aldehydes and aromatic amines. The 2,3-disubstituted-2,3-dihydroquinazolin-4(1 H)-one derivatives were obtained in yields ranging from 85% to 93% within a short reaction time. Due to the magnetization properties of MNP@Arg/ChCl, the catalyst can be easily separated from the reaction mixture and reused several times without significant loss of catalytic activity. This method is particularly attractive in the context of green chemistry due to its high catalytic efficiency, thermal stability, reusability, ease of recovery, and environmentally friendly features.

Herein, aniline was oxidatively polymerized in the presence of modified Mg-Al/LDH to prepare an acidic calix[4]arene modified Mg-Al/LDH-polyaniline based nanohybrid (MLDH-NH₂@PANI). The prepared nanohybrid was studied using a variety of characterization techniques, including FT-IR, PXRD, TGA, FE-SEM, EDX-MAPP, and Zeta potential. To remove Cr(VI) from the aqueous solution, different parameters were examined, including pH, sorbent dosage, contact time, initial concentration of Cr(VI), and removal ability in the presence of interfering ions. The results showed that MLDH-NH₂ co-existence improved the active sites in MLDH-NH₂@PANI nanohybrid and reduced the agglomeration of polymeric chains. The pseudo-second-order model provided a better fitting for the Cr(VI) adsorption onto MLDH-NH₂@PANI, according to kinetic experiments. The highest adsorption capacity of Cr(VI) on MLDH-NH₂@PANI was 420.0 mg /g at pH = 3.0, which was more than that of typical adsorbents. The isotherms were accurately reproduced using the Langmuir model. At pH = 3, It is proposed that the oxyanion forms of Cr(VI) (e.g., HCrO₄⁻) can interact electrostatically with protonated amine groups and form hydrogen bonds with calix[4]arene moieties as a potential mode of contact with the adsorbent. Moreover, a portion of the adsorbed Cr(VI) undergoes reduction to Cr(III) through an adsorption-coupled reduction process facilitated by the PANI chains, and the resulting Cr(III) is subsequently chelated onto the nanohybrid. The reusability studies showed that the adsorbents could be reused up to 4 cycles with over 80% adsorption efficiency. These findings suggest that the MLDH-NH₂@PANI nanohybrid proved to be a good candidate for Cr(VI) removal from contaminated water.

para-Sulfonated calix[4]arene, a bowl-shaped macrocycle possessing intrinsic porosity, was incorporated into the voids of the MIL-101(Cr) metal–organic framework by adsorptive loading from a solution.