Magnetically recoverable Fe 3 O 4 -ZnO/AOT nanocomposites: Synthesis of a core–shell structure via a novel and mild route for photocatalytic degradation of toxic dyes

Efficient Fenton-like degradation of tetracycline by stalactite-like CuCo-LDO/CN catalysts: The overlooked contribution of dissolved oxygen

In the Fenton-like processes, the resources that exist in the system itself (e.g., dissolved oxygen, electron-rich pollutants) are often overlooked. Herein, a novel CuCo-LDO/CN composite catalyst with a strong "metal-π" effect was fabricated by in situ calcination which could activate dissolved oxygen to generate active oxygen species and degrade the electron-rich pollutants directly. The CuCo-LDO/CN (1:10) with the largest specific surface aera, most C-O-M bonds and least oxygen vacancies exhibited the best catalytic performance for tetracycline (TC)degradation (TC removal efficiency 93.2% and mineralization efficiency 40%, respectively, after 40 min at neutral pH) compared to CuCo-LDO and other CuCo-LDO/CN composite catalysts. In the absence of H2O2, dissolved oxygen could be activated by the catalyst to generate O2·-and ·OH, which contributed to approximately 20.7% of TC degradation, providing a faster and cost-effective way for TC removal from wastewater. While in the presence of H2O2, it was activated by CuCo-LDO/CN to generate·OH as the dominant reactive oxygen species and meanwhile TC transferred electrons to H2O2 through C-O-M bonds, accelerating the Cu+/Cu2+ and Co2+/Co3+ redox cycles. The possible degradation pathways of TC were proposed, and the environmental hazard of TC is greatly mitigated according to toxicity prediction.

Constructing a metal-free 2D covalent organic framework for visible-light-driven photocatalytic reduction of CO2: a sustainable strategy for atmospheric CO2 utilization

A 2D polyimide-linked covalent organic framework (COF) with band gap energy of 2.2 eV is developed as a stable and efficient porous photocatalyst which shows CO2 reduction to formic acid, formaldehyde and methanol.

Rational design of magnetically separable core/shell Fe3O4/ZnO heterostructures for enhanced visible-light photodegradation performance

Magnetically separable core/shell Fe₃O₄/ZnO heteronanostructures (MSCSFZ) were synthesized by a facile approach, and their application for enhanced solar photodegradation of RhB was studied. The formation mechanism of MSCSFZ was proposed, in which Fe₃O₄ nanoparticles served as a template for supporting and anchoring the ZnO crystal layer as the shells. The morphology of MSCSFZ can be varied from spherical to rice seed-like structures, and the bandgap was able to be narrowed down to 2.78 eV by controlling the core–shell ratios. As a result, the MSCSFZ exhibited excellent visible-light photocatalytic activity for degradation of rhodamine B (RhB) in aqueous solution as compared to the controlled ZnO nanoparticles. Moreover, MSCSFZ could be easily detached from RhB solution and maintained its performance after 4 cycles of usage. This work provides new insights for the design of high-efficient core/shell recyclable photocatalysts with visible light photocatalytic performance.

Magnetically separable core/shell Fe₃O₄/ZnO heteronanostructures (MSCSFZ) were synthesized by a facile approach, and their application for enhanced solar photodegradation of RhB was studied.

Efficient clean-up of waters contaminated with diazinon pesticide using photo-decomposition of peroxymonosulfate by ZnO decorated on a magnetic core/shell structure

In the present study, ZnO nanoparticles were anchored on a magnetic core/shell structure (SiO₂@Fe₃O₄) to perpetrate ZnO@SiO₂@Fe₃O₄ and then coupled with UV light as a heterogeneous nanocatalyst for activating peroxymonosulfate (PMS) into diazinon (DZ) degradation. Several techniques like XRD (X-ray diffraction), BET (Brunaeur, Emmett and Teller), TEM (Transmission electron microscope), FESEM (Field emission-scanning electron microscope) coupled with EDS (Energy Dispersive X-ray Spectrometer), PL (photoluminescence), VSM (Vibrating Sample Magnetometer) and UV-vis diffuse reflectance spectroscopy (DRS) were applied for identification of catalyst features. A possible mechanism for PMS activation and DZ degradation was proposed in details. The effect of solution pH, various concentrations of catalyst, PMS and DZ, quenching agents, different chemical oxidants and co-existing anions was assessed as operating factors to determine the optimum conditions. PMS decomposed effectively in coupling with ZnO@SiO₂@Fe₃O₄ and UV. At optimal conditions, over 95 and 56% of DZ and TOC were removed during 60 min reaction, respectively. The complete degradation of DZ was confirmed using its absorption peak in UV-vis spectra analysis over 60 min treatment. A wide variety of free radicals was identified during quenching tests. HO^• and h⁺ played a pivotal role in the degradation process of DZ. Decreasing the degradation efficiency in the presence of anions was as Cl^- > CO₃^2- > NO₃^- > PO₄^3- > SO₄^2- > HCO₃^-. A negligible amount of leaching Fe (<0.2 mg/L) was found for ZnO@SiO₂@Fe₃O₄, indicating that the catalyst possesses a high stability in oxidation systems. In addition, a significant potential was achieved in reusing of catalyst within five consecutive runs. In conclusion, ZnO@SiO₂@Fe₃O₄/PMS/UV hybrid system can be utilized as a promising advanced oxidation process into efficient degradation of pesticides, thanks to easy recovery, high catalytic activity, co-production of different reactive species and high durability and recyclability potential.

Synthesis of a nanostructured pillar MOF with high adsorption capacity towards antibiotics pollutants from aqueous solution

In this study, various sonochemical conditions were applied to prepare the microsheets, nanosheets and nanoflowers of a metal-organic framework (MOF; [Zn₆(IDC)₄(OH)₂(Hprz)₂]_n) that is composed of Zn(II) cations coordinated with the linear N-donor piperazine (prz) and rigid planar imidazole-4,5-dicarboxylate (H₃IDC) ligands. The PXRD patterns approved purity of the samples and the FT-IR spectra related the detected bonds and functional groups to [Zn₆(IDC)₄(OH)₂(Hprz)₂]_n crystals. The morphological results indicated that any changes in the synthesis conditions can affect nucleation and morphology of the nanostructures. The prepared MOF nanosheets and nanoflowers (with particle size average of 95 and 116 nm, respectively) were employed to adsorb the ampicillin, amoxicillin and cloxacillin antibiotics. Then, the MOFs were calcined at 550 ℃ and atmospheric pressure to produce ZnO nanoparticles and the resultant nanoparticles were adopted to photodegrade the antibiotics. These nanoparticles can photodegrade 37% of the amoxicillin compounds within 180 min. Among the examined samples, the nanoflowers demonstrated the highest adsorption capacity by eliminating 92.5%, 88% and 89% of the antibiotic molecules from the 60-ppm amoxicillin, ampicillin and cloxacillin solutions, respectively. Also, these nanoflowers are thermally stable up to 365 ℃. The associated adsorption process was found to follow pseudo-first-order kinetics, in the case of amoxicillin.

The effect of different parameters under ultrasound irradiation for synthesis of new nanostructured Fe3O4@bio-MOF as an efficient anti-leishmanial in vitro and in vivo conditions

In this work, a magnetic bio-metal-organic framework (MBMOF) nanocomposite with porous-layer open morphology is synthesized through a simple sonochemical approach and its effects on Leishmania major (MRHO/IR/75/ER) under both in vitro and in vivo conditions are investigated. The effects of sonication time, initial concentration of reagents and sonication power on size and morphology of MBMOF nanocomposites have been investigated and optimized. A comparison was then made between the structural information of the nanostructures and that of the bio-metal-organic framework crystals. Using the powder X-ray diffraction (PXRD), field emission scanning electron microscope (FE-SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), energy dispersive analysis of X-ray (EDAX), vibrating sample magnetometer (VSM), thermogravimetric analysis (TGA), and Brunauer-Emmet-Teller (BET) techniques, the prepared MBMOF nanocomposites were characterized. The mean numbers of promastigotes (cell/ml) in different MBMOF concentrations (3.12, 6.25, 12.5, 25, 50, 100, 200 and 400 µg mL^-1) were determined by direct counting after 24, 48 and 72 h. Using MTT assays, the cytotoxic impacts of the MBMOF nanocomposites on promastigotes, intracellular amastigotes, and J774 macrophages were estimated. In order to investigate their therapeutic effects, the prepared MBMOF nanocomposites (25 and 12.5 µg mL^-1) were used as ointment three times a week to treat Leishmania major in BALB/c mice. The lesion size and weight of mice were assessed before and during the treatment. The parasitic loads were measured in spleen and liver through the culture. After 72 h, the INF-γ and IL-4 cytokines levels in the supernatant of the spleen culture were measured. To the best of the authors' knowledge, this study is the first to attempt to synthesize the bio-MOFs through an in-situ sonosynthesis route under ultrasound irradiation and examine their cytotoxicity effects on Leishmania major under in vitro and in vivo conditions.

Ultrasound-assisted synthesis of Zinc(II)-based metal organic framework nanoparticles in the presence of modulator for adsorption enhancement of 2,4-dichlorophenol and amoxicillin

In this study, under a sonochemical method, a 3D, porous Zn(II)-based metal-organic framework [Zn(TDC)(4-BPMH)]_n·n(H₂O) is produced, which is called compound 1. To this end, the dicarboxylate linker of TDC, (2,5-thiophene dicarboxylic acid) and the pillar spacer of 4-BPMH, (N,N-bis-pyridin-4-ylmethylene-hydrazine) were employed. Moreover, variations in the morphology and growth of the micro/nanoparticles of compound 1 were investigated in terms of the effect of temperature, ultrasound irradiation power, sonication time, initial reagent concentrations, and pyridine concentration as a modulator. DFT model was used to examine the sonication effect on the distribution of the pore sizes. Moreover, the preparation method effect on the porosity and removal of two sample pollutants (i.e., 2,4-dichlorophenol (24-DCP) and amoxicillin (AMX)) from wastewater was studied.

Morphology- and size-controlled synthesis of a metal-organic framework under ultrasound irradiation: An efficient carrier for pH responsive release of anti-cancer drugs and their applicability for adsorption of amoxicillin from aqueous solution

In this study, we have reported a biocompatible metal-organic framework (MOF) with ultra-high surface area, which we have shown to have uses as both a cancer treatment delivery system and for environmental applications. Using a sonochemical approach, highly flexible organic H₃BTCTB and ditopic 4,4'-BPDC ligands, along with modulators of acetic acid and pyridine were combined to prepare a Zn(II)-based metal-organic framework, DUT-32, [Zn₄O(BPDC)(BTCTB)_4/3(DEF)_39.7(H₂O)_11.3]. Powder X-ray diffraction (PXRD), field-emission scanning electron microscopy (FE-SEM), and Fourier transform infrared spectroscopy (FTIR) were used to characterize, the particle size, shape, and structure of the DUT-32. To show the effects of shape and size of DUT-32 micro/nano-structures on doxorubicin (DOX) drug release and amoxicillin (AMX) adsorption, time of sonication, initial reagent concentrations, irradiation frequency, and acetic acid to pyridine molar ratios were optimized. The drug-loaded DUT-32 was soaked in simulated body fluid (SBF) and the drug release ratio was monitored through release time to perform in vitro drug release test. A slow and sustained release was observed for DUT-32 micro/nano-structures, having a considerable drug loading capacity. At the pH values 7.4-4.5, various profiles of pH-responsive release were achieved. Also, the prepared DUT-32 micro/nano-structures are found to be biocompatible with PC3 (prostate cancer) and HeLa (cervical cancer) cell lines, when tested by MTT assay. Moreover, DUT-32 micro/nano-structures were studied to show AMX adsorption from aqueous solution. Finally, kinetic studies indicated that AMX adsorption and drug release of DOX via this MOF are of first-order kinetics.

Enhanced Fenton-like catalytic performance of N-doped graphene quantum dot incorporated CuCo2O4

In the present study, a novel nanocomposite based on CuCo₂O₄ and N-doped graphene quantum dots (N-GQDs) as an iron-free heterogeneous Fenton-like catalyst was prepared by a two-step solvothermal method.

The NiGa-LDH@NiWO4 nanocomposite as an electrode material for pseudocapacitors

NiGa-LDH@X-NiWO₄ (X: 3, 5 or 10 wt% NiWO₄) nanocomposites were prepared at room temperature under mild conditions.