Correction and removal of expression of concern: Palladium supported on mixed-metal-organic framework (Co-Mn-MOF-74) for efficient catalytic oxidation of CO.

[This corrects the article DOI: 10.1039/D0RA09970H.].

Corrigendum to "Gold-selenide quantum dots supported onto cesium ferrite nanocomposites for the efficient degradation of rhodamine B" [Heliyon 8(6) June 2023 e09652].

[This corrects the article DOI: 10.1016/j.heliyon.2022.e09652.].

Expression of concern: Palladium supported on mixed-metal-organic framework (Co-Mn-MOF-74) for efficient catalytic oxidation of CO.

Expression of Concern for 'Palladium supported on mixed-metal-organic framework (Co-Mn-MOF-74) for efficient catalytic oxidation of CO' by Reda S. Salama et al., RSC Adv., 2021, 11, 4318-4326, https://doi.org/10.1039/D0RA09970H.

Correction to "Role of NiO Nanoparticles in Enhancing Structure Properties of TiO2 and Its Applications in Photodegradation and Hydrogen Evolution".

[This corrects the article DOI: 10.1021/acsomega.1c03693.].

Synthesis and characterization of magnesium ferrite-activated carbon composites derived from orange peels for enhanced supercapacitor performance.

Supercapacitors have emerged as highly efficient energy storage devices, relying on electrochemical processes. The performance of these devices can be influenced by several factors, with key considerations including the selection of electrode materials and the type of electrolyte utilized. Transition metal oxide electrodes are commonly used in supercapacitors, as they greatly influence the electrochemical performance of these devices. Nonetheless, ferrites' low energy density poses a limitation. Hence, it is crucial to create electrode materials featuring unique and distinct structures, while also exploring the ideal electrolyte types, to enhance the electrochemical performance of supercapacitors incorporating magnesium ferrites (MF). In this study, we effectively prepared magnesium ferrites (MgFe2O4) supported on activated carbon (AC) derived from orange peels (OP) using a simple hydrothermal method. The resulting blends underwent comprehensive characterization employing various methods, including FTIR, XRD, TEM, SEM, EDX, and mapping analysis. Moreover, the electrochemical performance of MgFe2O4@AC composites was evaluated using GCD and CV techniques. Remarkably, the MF45-AC electrode material showed exceptional electrochemical behavior, demonstrating a specific capacitance of 870 F·g-1 within current density of 1.0 A g-1 and potential windows spanning from 0 to 0.5 V. Additionally, the prepared electrodes displayed exceptional cycling stability, with AC, MF, and MF45-AC retaining 89.6%, 94.2%, and 95.1% of their initial specific capacitance, respectively, even after 5000 cycles. These findings underscore the potential of MF-AC composites as superior electrode materials for supercapacitors. The development of such composites, combined with tailored electrolyte concentrations, holds significant promise for advancing the electrochemical performance and energy density of supercapacitor devices.

Correction: The role of PMA in enhancing the surface acidity and catalytic activity of a bimetallic Cr-Mg-MOF and its applications for synthesis of coumarin and dihydropyrimidinone derivatives.

[This corrects the article DOI: 10.1039/D0RA03591B.].

Natural-based coagulants/flocculants as sustainable market-valued products for industrial wastewater treatment: a review of recent developments.

Industrial wastewater is categorized as a voracious consumer of fresh water and a high-strength source of pollution. Coagulation-flocculation is a simple and cost-effective technique for removing organic/inorganic compounds and colloidal particles from industrial effluents. Despite the outstanding natural properties, biodegradability, and efficacy of natural coagulants/flocculants (NC/Fs) in industrial wastewater treatment, their significant potential to remediate such effluents is underappreciated, particularly in commercial scale applications. Most reviews on NC/Fs focused on the possible application of plant-based sources such as plant seeds, tannin, certain vegetables/fruit peels, and their lab-scale potential. Our review expands the scope by examining the feasibility of using natural materials from other sources for industrial effluent decontamination. By analyzing the latest data on NC/Fs, we identify the most promising preparation techniques for making these materials stable enough to compete with traditional options in the marketplace. An interesting presentation of the results of various recent studies has also been highlighted and discussed. Additionally, we highlight the recent success of using magnetic-natural coagulants/flocculants (M-NC/Fs) in treating diverse industrial effluents, and discuss the potential for reprocessing spent materials as a renewable resource. The review also offers different concepts for suggested large-scale treatment systems used by MN-CFs.

Design and Development of Novel Composites Containing Nickel Ferrites Supported on Activated Carbon Derived from Agricultural Wastes and Its Application in Water Remediation.

Recently, efficient decontamination of water and wastewater have attracted global attention due to the deficiency in the world's water sources. Herein, activated carbon (AC) derived from willow catkins (WCs) was successfully synthesized using chemical modification techniques and then loaded with different weight percentages of nickel ferrite nanocomposites (10, 25, 45, and 65 wt.%) via a one-step hydrothermal method. The morphology, chemical structure, and surface composition of the nickel ferrite supported on AC (NFAC) were analyzed by XRD, TEM, SEM, EDX, and FTIR spectroscopy. Textural properties (surface area) of the nanocomposites (NC) were investigated by using Brunauer-Emmett-Teller (BET) analysis. The prepared nanocomposites were tested on different dyes to form a system for water remediation and make this photocatalyst convenient to recycle. The photodegradation of rhodamine B dye was investigated by adjusting a variety of factors such as the amount of nickel in nanocomposites, the weight of photocatalyst, reaction time, and photocatalyst reusability. The 45NFAC photocatalyst exhibits excellent degradation efficiency toward rhodamine B dye, reaching 99.7% in 90 min under a simulated source of sunlight. To summarize, NFAC nanocomposites are potential photocatalysts for water environmental remediation because they are effective, reliable, and reusable.

Gold-selenide quantum dots supported onto cesium ferrite nanocomposites for the efficient degradation of rhodamine B.

In this work, different weight percentage of gold-selenide quantum dots (AuSe QDs) (1.0, 2.5, 5.0 and 7.0 wt.%) were successfully synthesized and decorated on cesium ferrite nanocomposite (Cs2Fe2O4 NC). The as-prepared pure AuSe QDs, pure Cs2Fe2O4 NC, and x wt.% AuSe QDs/Cs2Fe2O4 NC photocatalysts were investigated using different characterization techniques such as nitrogen adsorption desorption isotherms (BET), X-ray diffraction patterns (XRD), transmission electron microscopy (TEM), and UV-vis absorption spectroscopy. The results show that AuSe QDs were uniformly distributed on Cs2Fe2O4NCs surface as spherical dots with an average size of 1.0-8.0 nm. While the Cs2Fe2O4 NCs possess an average size between 10 to 35 nm. The photocatalytic performance of x wt. % AuSe QDs/Cs2Fe2O4NCs were measured through the photodegradation of rhodamine B (RhB) dye as a model water pollutant, under a150 W-Mercury lamp with a filter (JB400) as a simulated source of visible light. The results revealed that the % degradation of RhB increased from 50.0 %, 59.1 %, 76.4 %, and to 99.15 % within 150 min for the pure Cs2Fe2O4, 1.0, 2.5 and 5.0 wt.% AuSe QDs/Cs2Fe2O4 NC photocatalysts, respectively. The 5.0 wt.% AuSe/Cs2Fe2O4 NC sample showed highest photocatalytic activity. The effect of recycling also studied. High photocatalytic performance and superior stability confirmed that the prepared nanocomposites act as good photocatalysts.

Role of NiO Nanoparticles in Enhancing Structure Properties of TiO2 and Its Applications in Photodegradation and Hydrogen Evolution.

Pure and modified mesoporous TiO2 nanoparticles with different loadings of NiO (3-20.0 wt %) were prepared through the surfactant-assisted sol-gel approach with the use of cetyltrimethylammonium bromide as a template. The optical and structural properties of different samples were examined using N2 adsorption-desorption analysis, energy-dispersive spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, UV-vis spectroscopy, Fourier transform infrared spectroscopy, and photoluminescence (PL) spectroscopy. X-ray diffraction results confirmed the insertion of Ni2+ into the lattice of TiO2, and the crystallite size reduced remarkably after the addition of NiO. The diffuse reflectance spectroscopy spectra displayed obvious red shift in the absorption edges, and new absorption bands appeared in the visible region when NiO was added, which indicates the formation of surface defects and oxygen vacancies. The optical band gap of TiO2 reduced sharply when the contents of NiO were increased. The increase in the surface defects as well as oxygen vacancies were examined using PL spectroscopy. The photocatalytic performance of the as-synthesized samples was investigated over photodegradation of brilliant green (BG) and phenol and hydrogen generation under visible light. 10% NiO/TiO2 exhibited the highest photocatalytic efficiency. The photocatalytic activity was improved due to the creation of a p-n junction at the interface of NiO/TiO2, which efficiently promotes the separation of photogenerated electron/hole pairs and consequently enhances its photodegradation activity. According to the photocatalytic activity results, NiO contents were considered one of the most important factors affecting the photodegradation of BG and phenol and H2 evolution. Also, we discussed the mechanism of photodegradation, mineralization (total organic carbon), and photocatalytic reaction kinetics of BG and phenol.

Facile and Green Synthesis of Silver Quantum Dots Immobilized onto a Polymeric CTS-PEO Blend for the Photocatalytic Degradation of p-Nitrophenol.

Immobilization of inorganic metal quantum dots (especially, noble transition metals) onto organic polymers to synthesize nanometal-polymer composites (NMPCs) has attracted considerable attention because of their advanced optical, electrical, catalytic/photocatalytic, and biological properties. Herein, novel, highly efficient, stable, and visible light-active NMPC photocatalysts consisting of silver quantum dots (Ag QDs) immobilized onto polymeric chitosan-polyethylene oxide (CTS-PEO) blend sheets have been successfully prepared by an in situ self-assembly facile casting method as a facile and green approach. The CTS-PEO blend polymer acts as a reducing and a stabilizing agent for Ag QDs which does not generate any environmental chemical pollutant. The prepared x wt % Ag QDs/CTS-PEO composites were fully characterized through X-ray diffraction, Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), thermogravimetric analysis, and UV/visible spectroscopy. The characterization results indicated the successful synthesis of the Ag QDs/CTS-PEO composites by the interactions and complexation between x wt % Ag QDs and CTS-PEO blend sheets. TEM images revealed small granules randomly distributed onto the CTS-PEO blend sheets, indicating the immobilization of Ag QDs onto CTS-PEO composites. The presence of a surface plasmon resonance (SPR) band and the shifting of the absorption edge toward higher wavelengths in the UV/vis spectra indicated the formation of x wt % Ag QDs/CTS-PEO composites. The Ag QDs in the polymeric blend matrix led to remarkable enhancement in the optical, thermal, electrical, and photocatalytic properties of x wt % Ag QDs/CTS-PEO composites. The photocatalytic efficiency of the prepared composites was evaluated by the photodegradation of p-nitrophenol (PNP) under simulated sunlight. The maximum photocatalytic degradation reached 91.1% efficiency within 3 h for the 12.0 wt % Ag QDs/CTS-PEO photocatalyst. Generally, the Ag QDs immobilized onto CTS-PEO blend composites significantly enhance the SPR effect and the synergistic effect and reduce the band gap, leading to a high photocatalytic activity.

Palladium supported on mixed-metal-organic framework (Co-Mn-MOF-74) for efficient catalytic oxidation of CO.

Successful monometallic and bimetallic metal-organic frameworks with different Co/Mn ratios have been synthesized under solvothermal conditions. The as-synthesized MOFs followed by deposition of Pd nanoparticles with 0.5 to 7 wt%. The XRD, BET, SEM, TEM, EDAX and FT-IR characterization results reveal that bimetallic MOFs and Pd nanoparticles were finely dispersed on the prepared MOFs surfaces. XRD results confirm the formation of the desire MOFs and show the high degree of dispersion of Pd nanoparticles. TEM images show that Pd nanoparticles are nano-sized with almost uniform shape. EDAX shows that Pd nanoparticles successfully loaded on Co0.5-Mn0.5-MOF-74 catalyst. CO oxidation as a model reaction was then used to assess the catalytic performance of the prepared catalysts. The catalytic activity results show enhancement in the catalytic activities of monometallic MOFs after introducing another metal in the same framework and show an excellent improvement in CO conversion after loading with Pd nanoparticles. Furthermore, the samples that contain Pd nanoparticles exhibits higher catalytic activities which raised with increasing the content of Pd nanoparticles.

The role of PMA in enhancing the surface acidity and catalytic activity of a bimetallic Cr-Mg-MOF and its applications for synthesis of coumarin and dihydropyrimidinone derivatives.

In the present study, a bimetallic Cr-Mg-MOF was successfully synthesized by the solvothermal method and then modified by loading different amounts of phosphomolybdic acid (PMA) using a simple wet impregnation technique. The morphological and structural properties of the prepared samples were investigated using X-ray diffraction, TEM, SEM, BET and FTIR spectroscopy. Importantly, Mg doping not only caused the Cr-Mg-MOF to have a higher surface area than MIL-101 (Cr) or MOF-74 (Mg), but the strategy of doping metal ions can be an effective way to improve the adsorption performance of MOFs. The surface acidity and the acid strength of the samples were determined using potentiometric titration and the FTIR of pyridine adsorption. The incorporation of PMA crystals gradually enhances both the surface acidity and the acid strength of the PMA/Cr-Mg-MOF catalysts up to 75 wt%. The catalytic performances of the prepared catalysts were tested in two acid-catalyzed organic transformations, namely, 7-hydroxy-4-methyl coumarin and 3,4-dihydropyrimidinone. In the two reactions, the catalytic activity attains the maximum value at 75 wt% PMA loading. The PMA catalysts supported on Cr-Mg-MOF are potentially promising heterogeneous catalysts for acid-catalyzed organic transformations in environmentally friendly processes, to replace the use of conventional homogeneous PMA catalysts.

Synthesis of sulfamic acid supported on Cr-MIL-101 as a heterogeneous acid catalyst and efficient adsorbent for methyl orange dye.

Typical highly porous metal-organic framework (MOFs) materials based on chromium benzenedicarboxylates (Cr-BDC) were prepared through a one-pot hydrothermal synthesis, and were then modified by loading the appropriate ratio of sulfamic acid (SA) using a simple impregnation technique. Pure and modified MIL-101 was characterized by XRD, TEM, SEM and FT-IR measurements. TEM and SEM measurements confirmed that the MIL-101 particles preserved their regular octahedral structure after loading with different weight contents of sulfamic acid. The total number of acid sites and Brønsted to Lewis acid sites ratio (B/L) were examined using potentiometric titration and pyridine adsorption. The acid strength and surface acidity of SA/MIL-101 gradually increased after the modification of Cr-MIL-101 by sulfamic acid crystals up to 55 wt%, then decreased again. The catalytic performance of the solid catalysts was confirmed in the synthesis of 14-phenyl-14H-dibenzo [a,j] xanthene and 7-hydroxy-4-methyl coumarin. In the two reactions, the sample with 55% sulfamic acid loaded on MIL-101 displayed the highest catalytic activity and acidity. The adsorption behaviors of sulfamic acid loaded on MIL-101 materials for methyl orange (MO) as an anionic dye were studied, and were exceptionally suitable for the Langmuir adsorption isotherm. All loaded adsorbents showed high adsorption capacity for methyl orange at 25 °C. The results indicate that the adsorption capacity was modified by changing the amount of sulfamic acid loaded on MIL-101.