High Performance Magnetically Separable G‐C3N4/γ‐Fe2O3/TiO2 Nanocomposite with Boosted Photocatalytic Capability towards the Cefixime Trihydrate Degradation under Visible‐Light

A magnetically separable g‐C3N4/γ‐Fe2O3/TiO2 nanocomposite is synthesized as an intensely effectual visible‐light‐driven photocatalyst. It is fully characterized by FT‐IR, XPS, XRD, VSM, DRS, SEM, TEM, BET, EDS, and elemental mapping techniques. Based on the Tauc plot of (αhν)2 vs. hυ, the value of band gap energy for g‐C3N4/γ‐Fe2O3/TiO2 is estimated to be 2.6 eV, which proves the high capability of the catalyst to enhance the photoinduced electron‐holes separation and improves its visible‐light photocatalytic performance. The high photocatalytic activity of this catalyst towards the cefixime trihydrate (CEF) degradation, under visible‐light radiation can be ascribed to the synergistic optical effects between g‐C3N4, γ‐Fe2O3, and TiO2. Using central composite design (CCD) based on response surface methodology (RSM), the maximum degradation efficiency of about 98 % was obtained at the optimal conditions comprising the CEF amount of 20 mg/L, photocatalyst value of 0.04 g/L, irradiation intensity of 9 W/m2, and pH of 5.5, at 90 min. Utilizing an innocuous visible‐light source, almost complete mineralization of CEF (based on TOC analysis), using a very low amount of photocatalyst, applying air as the oxidant, and convenient magnetic separation of the catalyst from the reaction media and its ease of recycling for at least seven consecutive runs are the major highlights of this protocol.Financial support of this project by the University of Birjand Research Council and the XPS facilities of the University of Alicante is appreciated

g-C3N4/γ-Fe2O3/TiO2/Pd: a new magnetically separable photocatalyst for visible-light-driven fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature

In this paper, a new visible-light harvesting photocatalyst denoted as g-C3N4/γ-Fe2O3/TiO2/Pd was successfully fabricated and fully characterized by different techniques including FT-IR, XPS, XRD, TEM, SEM, elemental mapping, VSM, DRS, and ICP analysis. The as-prepared catalyst was utilized as an efficient magnetically separable photocatalyst in the fluoride-free Hiyama and Suzuki–Miyaura cross-coupling reactions at room temperature under visible light irradiation. By using this approach good to excellent yields of biaryls were achieved from the reaction of various aryl iodides/bromides and even chlorides as highly challenging substrates, which are more available and cheaper than aryl iodides and bromides, with triethoxyphenylsilane or phenylboronic acid. The superior photocatalytic activity of g-C3N4/γ-Fe2O3/TiO2/Pd could be attributed to the synergistic catalytic effects of Pd nanoparticles and g-C3N4/γ-Fe2O3/TiO2. Utilizing a sustainable and safe light source, no need to use any additive or heat, using an eco-friendly solvent and long-term stability and magnetic recyclability of the catalyst for at least seven successive runs are the advantages that support the current protocol towards green chemistry.Financial support of this project by the University of Birjand Research Council and the XPS facilities of the University of Alicante is appreciated

ZnCo2O4/g-C3N4/Cu nanocomposite as a new efficient and recyclable heterogeneous photocatalyst with enhanced photocatalytic activity towards the metronidazole degradation under the solar light irradiation

In this study, ZnCo2O4/g-C3N4/Cu is synthesized as a new and highly effectual solar light-driven heterogeneous photocatalyst. The prepared photocatalyst is characterized using FT-IR, XRD, XPS, DRS, FESEM, TEM, EDS, and elemental mapping techniques. The performance of ZnCo2O4/g-C3N4/Cu is studied towards the metronidazole (MNZ) degradation under solar light irradiation. The kinetics of MNZ degradation and efficacy of the operational parameters comprising the initial MNZ amount (10–30 mg L−1), photocatalyst dosage (0.005–0.05 g L−1), pH (3–11), and contact time (5–30 min) on the MNZ degradation process are investigated. Surprisingly, the ZnCo2O4/g-C3N4/Cu nanocomposite presents a privileged photocatalytic performance towards the MNZ degradation under solar light irradiation. The enhanced photocatalytic activity of this photocatalyst can be ascribed to the synergistic optical effects of ZnCo2O4, g-C3N4, and Cu. The value of band gap energy for ZnCo2O4/g-C3N4/Cu is estimated to be 2.3 eV based on the Tauc plot of (αhν)2 vs. hν. The radical quenching experiments confirm that the superoxide radicals and holes are the principal active species in the photocatalytic degradation of MNZ, whereas the hydroxyl radicals have no major role in such degradation. The as-prepared photocatalyst is simply isolated and recycled for at least eight runs without noticeable loss of the efficiency. Using the natural sunlight source, applying a very low amount of the photocatalyst, neutrality of the reaction medium, short reaction time, high efficiency of the degradation procedure, utilizing air as the oxidant, low operational costs, and easy to recover and reuse of the photocatalyst are the significant highlights of the present method. It is supposed that the current investigation can be a step forward in the representation of an efficacious photocatalytic system in the treatment of a wide range of contaminated aquatic environments.Financial support of this project by University of Birjand Research Council is appreciated. The authors also thank the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (project PID2019-107268GB-I00) and the University of Alicante

Solar light induced photocatalytic degradation of tetracycline in the presence of ZnO/NiFe2O4/Co3O4 as a new and highly efficient magnetically separable photocatalyst

In this study, a new solar light-driven magnetic heterogeneous photocatalyst, denoted as ZnO/NiFe2O4/Co3O4, is successfully prepared. FT-IR, XPS, XRD, VSM, DRS, FESEM, TEM, EDS, elemental mapping, and ICP analysis are accomplished for full characterization of this catalyst. FESEM and TEM analyses of the photocatalyt clearly affirm the formation of a hexagonal structure of ZnO (25–40 nm) and the cubic structure of NiFe2O4 and Co3O4 (10–25 nm). Furthermore, the HRTEM images of the photocatalyst verify some key lattice fringes related to the photocatalyt structure. These data are in very good agreement with XRD analysis results. According to the ICP analysis, the molar ratio of ZnO/NiFe2O4/Co3O4 composite is obtained to be 1:0.75:0.5. Moreover, magnetization measurements reveals that the ZnO/NiFe2O4/Co3O4 has a superparamagnetic behavior with saturation magnetization of 32.38 emu/g. UV-vis DRS analysis indicates that the photocatalyst has a boosted and strong light response. ZnO/NiFe2O4/Co3O4, with band gap energy of about 2.65 eV [estimated according to the Tauc plot of (αhν)2 vs. hν], exhibits strong potential towards the efficacious degradation of tetracycline (TC) by natural solar light. It is supposed that the synergistic optical effects between ZnO, NiFe2O4, and Co3O4 species is responsible for the increased photocatalytic performance of this photocatalyst under the optimal conditions (photocatalyst dosage = 0.02 g L−1, TC concentration = 30 mg L−1, pH = 9, irradiation time = 20 min, and TC degradation efficiency = 98%). The kinetic study of this degradation process is evaluated and it is well-matched with the pseudo-first-order kinetics. Based on the radical quenching tests, it can be perceived that •O2− species and holes are the major contributors in such a process, whereas the •OH radicals identify to have no major participation. The application of this methodology is implemented in a facile and low-cost photocatalytic approach to easily degrade TC by using a very low amount of the photocatalyst under natural sunlight source in an air atmosphere. The convenient magnetic isolation and reuse of the photocatalyst, and almost complete mineralization of TC (based on TOC analysis), are surveyed too, which further highlights the operational application of the current method. Notably, this method has the preferred performance among the very few methods reported for the photocatalytic degradation of TC under natural sunlight. It is assumed that the achievements of this photocatalytic method have opened an avenue for sustainable environmental remediation of a broad range of contaminants.The authors gratefully acknowledge the financial support of this study by University of Birjand Research Council. Thanks to the Spanish Ministerio de Economía, Industria y Competitividad, Agencia Estatal de Investigación (AEI) and Fondo Europeo de Desarrollo Regional (FEDER, EU) (project PID 2019-107268GB-I00) and to the University of Alicante

Immobilized piperazine on the surface of graphene oxide as a heterogeneous bifunctional acid–base catalyst for the multicomponent synthesis of 2-amino-3-cyano-4H-chromenes

Immobilized piperazine on the surface of graphene oxide (piperazine-GO) is synthesized and characterized by different methods such as FT-IR, solid-state 29Si{1H} and 13C{1H} CP/MAS NMR, elemental analysis, TGA, TEM, FE-SEM, XPS, and TPD. Subsequently, it is used as a heterogeneous bifunctional acid–base catalyst for the efficient multicomponent reaction of malononitrile, different active compounds containing enolizable C–H bonds and various aryl/alkyl aldehydes in aqueous ethanol. A wide variety of 2-amino-3-cyano-4H-chromenes are synthesized in the presence of this heterogeneous catalyst in good to high yields and with short reaction times. The catalyst is easily separated and reused for at least six times without significant loss of activity. The acidic nature of GO improves the catalytic activity of the supported piperazine and also provides heterogeneity to the catalyst. Use of aqueous ethanol as a green solvent, high turnover numbers (TON), facile catalyst recovery and reuse, simple work-up and generality of the method make this protocol an environmentally benign procedure for the synthesis of the title heterocycles.Financial support for this project by the University of Birjand Research Council and access to the solid-state NMR facilities at the Department of Chemistry, Aarhus University and the XPS facilities of the University of Alicante are acknowledged

Gingivitis and periodontitis as a risk factor for stroke: A case-control study in the Iranian population

Background: Periodontitis and gingivitis are one of the most infectious diseases in human. Several studies have been carried out on dependence of periodontitis and stroke. The aim of this study was to investigate the gingivitis and periodontitis as a risk factor for stroke in Iranian population. Materials and Methods: A case-control study was conducted on 100 patients suffering from stroke as case group, and 100 hospitalized patients as control group. The case group included 42 males and 58 females, and in control group there were 44 males and 56 females. Using a University of North Carolina-15 manual probe, the clinical attachment level, the distance between the cemento-enamel junction and the probed base of the periodontal pocket, were recorded by gingival and periodontal indexes. The data were analyzed by multiple logistic regressions, Chi-square test, Fisher′s test, t-test, Man Whitney, and SPSS11.5 software program. P < 0.05 was considered as significant. Results: The case group included 42 males and 58 females, and in control group 44 males and 56 females were included. In this investigation, the average of gingival index in men and women of case group was 1.22 ± 0.55 and 1.31 ± 0.55, respectively. This study showed that the average of gingival index in case group was more than control group. Periodontal index in both groups in men was more than women. The moderate and severe periodontitis in case group were more than that of control group (P = 0.003, P = 0.001). Conclusion: The result of this study shows that there is a significant relation between stroke and periodontal index; however, there isn′t any significant relation between stroke and gingival index