mohammadreza sazegar

Mesoporous silica nanoparticles (MSNs) were synthesized hydrothermally and modified with Co2+ and Zn2+. The as-prepared samples were denoted as MSN, Co-MSN(X), and Zn-MSN(X), where X is the Si/M molar ratio. In addition, co-modified MSN samples with both cations were also prepared and denoted as Co-Zn(Y)-MSN(X), where Y indicates the Zn2+ content in the range of 1-7 wt.% relative to Co2+. Correctness of the anticipated structures was approved by FTIR, XRD, SEM, EDX, BET, and XRF analyses. It was found that Co-Zn(7)-MSN(75) can be used as an efficient photocatalyst for discoloration of basic red 5 under very mild conditions. Up to 86% of basic red 5 was discolored after 3.75 h under the optimized conditions including catalyst dosage of 0.025 mg mL-1, pH=7, and irradiation of 4×8 W UV (254 nm) lamps. By using the Langmuir–Hinshelwood kinetics model, it was found that the reaction followed a pseudo-first-order kinetic.

Doxorubicin (DOX), which is used to treat malignant cancerous tumors, has a high toxicity that by controlling the release of the drug into tumor cells, at the right time and place, the toxicity of the released drug and its side effects can be reduced. In this study, we investigated the release of doxorubicin from SiO2/DOX nanofibers in vitro. Electospun synthesized nanofibers from SiO2/DOX nanoparticles, were used to investigate the release of doxorubicin anticancer drug. X-ray diffraction (XRD) technique showed amorphous structure for nanofibers. According to field emission scanning electron microscopy (FESEM) images, the diameter and approximate length of the synthesized nanofibers were 300-400 nm and several tens of micrometers. Based on the analysis of X-energy diffraction (EDX) spectroscopy, the amount of silicon, oxygen, carbon, nitrogen and chlorine in the samples were: 30.18, 31.84, 29.83, 4.41, and 3.75 percent in the samples, respectively. Xmap analysis showed the homogeneous distribution of silicon, oxygen, carbon, chlorine and nitrogen atoms in nanofibers. Functional species and chemical bonds of nanofibers were detected by FT-IR analysis and showed that silicon has peaks at 1090, 804 cm-1 are related to asymmetric tensile, symmetric tensile vibrations at the Si–O–Si bond. Moreover, vibrations of Si–OH were appeared in the range of 3200 and 3600 cm-1. Drug release to applicant synthesized nanofibers, was investigated in vitro at 37 °C and pH=5.4. As a result, the produced nanofibers have the best and longest release time at pH=5.4 and can be used as drug carriers in targeted treatment anticancer drugs.

A novel series of the Co/Zn-MSN catalysts with Si/Zn molar ratio of 10 and 1, 3, 5 and 7 wt% Cobalt (denoted by CZ-X-MSN) were synthesized using post-synthesis methods. The samples were characterized by XRD, SEM, FTIR, TEM and nitrogen sorption methods. With a constant Si/Zn ratio, the increase of cobalt species from 1 to 7 wt% led to decrease the catalysts surface area from 408 m2g-1 for CZ-1-MSN to 322 m2g-1 for CZ-7-MSN. The catalyst activities were investigated for Schiff base synthesis by the reaction of cyclohexanone with 2,4-dinitrophenylhydrazine under UV irradiation. The activity of the catalysts in the Schiff base synthesis followed the order of Zn-MSN-10 < CZ-1-MSN < CZ-7-MSN < CZ-3-MSN < CZ-5-MSN. The CZ-5-MSN sample exhibited the highest performance with the conversion and selectivity of cyclohexanone to the Schiff base product were 98 and 97%, respectively, under UV light at 298 K for 10 min. The superior catalytic performance of CZ-5-MSN includes high yield, low reaction temperature, short reaction time and friendly environment. This probably was related to stronger metal-support interaction and metals dispersion. This study provides the new perspective on the synthesis of CZ-X-MSN towards an excellent performance of Schiff base structure under UV irradiation.