Brunner-Emmet-Teller Research Articles

Understanding the Environmental Sensitivity of Copper‐Metal Oxides Interactions in Cu/ZnO and Cu/Al2O3 Catalysts

AbstractTernary Cu/ZnO/Al2O3 catalysts are one of the most important industrial catalysts and show excellent activity in methanol reforming reaction. However, it is challenging to elucidate the metal support interactions, which critically influence the catalyst structure and performance, due to their environmentally sensitive nature. This study examines the interactions between Cu and Al2O3 and ZnO, after reductive treatments of the Cu/Al2O3 and Cu/ZnO model catalysts with varying temperatures and hydrogen concentration. A combination of Brunner‐Emmet‐Teller (BET) measurements, X‐ray diffraction (XRD), N2O titration, diffuse reflectance infrared Fourier transformations spectroscopy (DRIFTS) and high‐resolution transmission electron microscopy (HRTEM) provided comprehensive insights into the structural evolution of the catalysts.

The Synthesis and Application of Chitosan@Ag2O@Mn3O4 Three‐Phase Nanocomposite as a Heterogeneous Catalyst in the Synthesis of 2‐Hydroxynaphthalenepyrimidine Trione

ABSTRACTThe catalyst is often the most expensive element in a chemical process, rather than the reactants or products. Apart from the financial benefits, it is equally crucial to recover and reuse the catalyst to prevent waste and enhance the process's greenness. This study successfully synthesized the new, superior, and recyclable heterogeneous chitosan@Ag2O@Mn3O4 three‐phase nanocatalyst with high surface area and stability using Ag2O and Mn3O4 nanoparticles that stabilized on chitosan by copreparation method and was characterized by Fourier transform infrared (FT‐IR), scanning electron microscopy (SEM), energy dispersive X‐ray (EDX), transmission electron microscopy (TEM), surface mapping (mapping), X‐ray diffraction (XRD), Brunner–Emmett–Teller (BET), thermal gravimetric analysis (TGA), and differential scanning calorimetry (DSC) techniques in detail. Following, the efficiency of the synthesized nanocatalyst in the preparation of 2‐hydroxynaphthalenepyrimidine triones using the reaction of aromatic aldehydes, β‐naphthol, and barbituric acid derivatives was investigated and proved. The advantages of this method include performing reactions at room temperature, green media, short reaction times, and the easy purification of the products.

[formula omitted] Affects the crystalline calcium silicate hydrate minerals synthesized by fly ash-based silicon extraction solution and lime milk

When extracting amorphous silicon from fly ash using a strong alkaline solution, other elements such as Al also enter the silicon extraction solution in the form of AlOH4−. To systematically investigate the impact of AlOH4− on the synthesis of typical calcium silicate hydrate crystals in a silicon extraction solution, a specific amount of AlOH4− was added to the silicon extraction solution, and calcium silicate was hydrothermally synthesized at 90℃ and 230℃. Scanning electron microscopy (SEM) and Brunner−Emmet−Teller (BET) analysis revealed that with the increasing in AlOH4− content, microporous calcium silicate gradually loses its microporous morphology. While the specific surface area shows no significant change, the median pore diameter first increases from 1.47 nm to 1.58 nm and then decreases to 1.55 nm. The xonotlite fibers underwent a gradual refinement, diminishing from 0.28 to 0.15 µm. Simultaneously, the specific surface area increases from 28.87 to 56.8 m2/g. At an AlOH4− concentration of 3 mol/L, the microscopic morphology transforms into a sheet-like structure. X-ray diffraction (XRD) analysis reveals that AlOH4− promotes the formation of tobermorite while inhibiting the further development of calcium silicate. Additionally, Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance indicate that Al can replace Si in the calcium silicate hydrate system, primarily substituting positions the Q2 and Q3 sites. Qualitatively, it is suggested that with the increasing incorporation of Al, the polymerization degree of the silicon-oxygen tetrahedra decreases. According to experimental results, the concentration of AlOH4− should be below 0.05 mol/L when synthesizing microporous calcium silicate hydrate and less than 0.2 mol/L when synthesizing fibrous xonotlite-type calcium silicate hydrate.

Solar driven highly efficient photocatalyst based on Dy2O3 nanorods deposited on reduced graphene oxide nanocomposite for methylene blue dye degradation.

In recent years, the demand for rare earth elements has surged due to their unique characteristics and diverse applications. This investigation focuses on utilizing the rare earth element dysprosium oxide (Dy2O3) for the photocatalytic oxidation of model pollutants under solar light irradiation. A novel RGO-Dy2O3 nanocomposite photocatalyst was developed using a solvothermal approach, Dy2O3 nanorods uniformly deposited onto reduced graphene oxide (RGO) nanosheets. Comprehensive characterization techniques, including Brunner-Emmett-Teller (BET), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR), Raman spectroscopy, high resolution - transmittance electron microscopy (HR-TEM), field emission-electron scanning microscopy (FE-SEM), atomic force microscopy (AFM), electron paramagnetic resonance spectroscopy (EPR), photoluminescence spectroscopy (PL), and electrochemical impedance spectroscopy EIS techniques. The UV-visible diffusive reflectance spectroscopy (UV-Vis-DRS) studies revealed a band gap energy of 3.18eV and a specific surface area of 114 m2/g for the fabricated RGO-Dy2O3 nanocomposite. The RGO-Dy2O3 nanocomposite demonstrated a high photocatalytic degradation efficiency of 98.1% at neutral pH for methylene blue (MB) dye for the dye concentration of 10ppm. The remarkable photocatalytic performance was achieved within 60min under solar light irradiation. Reusability tests demonstrated stability, maintaining over 90% photocatalytic efficiency after three cycles. The EPR spectra and quenching experiments confirmed that photogenerated hydroxyl radicals significantly influence the photodegradation processes. The RGO-Dy2O3 nanocomposite photocatalyst, with its green, easy preparation process and recycling capabilities, presents an ideal choice for various applications. It offers a viable alternative for the photocatalytic degradation of organic dyes in real wastewater, contributing to sustainable environmental remediation.

Nanostructured codoped neodymium orthoferrite synthesized via the hydrothermal route for photocatalytic annihilation of crystal violet dye

Current research demonstrates the synergistic effects of gadolinium (Gd)/copper (Cu) codoping and nanotechnology on various physicochemical and photocatalytic features of neodymium iron oxide (NIO) perovskites. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) studies the synthesis of pure neodymium oxide (NIO-I) and its codoped counterpart (NIO-II) with a perovskite-type crystal structure via simple hydrothermal techniques. Through codoping and nanostructural synthesis, the surface characteristics, as well as the optical, electrical, and optoelectronic properties of the neodymium iron oxide perovskite, were enhanced, as confirmed by Brunner−Emmett−Teller (BET), UV/Vis, current−voltage (I−V), and photoluminescence (PL) studies. In terms of photocatalytic activity, the NIO-II perovskite outperforms its undoped NIO-I counterpart, eliminating 91.8 % of crystal violet (CV) dye in less than 50 min with a rate constant value (k) of 0.019 min−1. However, the undoped counterpart removed 63.8 % of the CV dye, with a comparatively lower rate constant of 0.013 min−1 under the same conditions. Under alkaline conditions, the NIO-II catalyst demonstrates superior efficiency in degrading CV dye; moreover, it maintains an efficiency of 96.8 %, even after undergoing five cycles of reuse. Through the use of rare earth and transition metal codoping, this study reveals a new way to fine-tune the structural and other pertinent properties of semiconductor perovskites, ensuring their practical use for the treatment of polluted water.

Highly efficient activation of peroxymonosulfate via KOH-activated Fe@NC for the degradation of bisphenol A.

In this study, the KOH-modified Fe-ZIF-derived carbon materials (Fe@NC-KOH-x) were designed for Fenton-like systems to enhance bisphenol A (BPA) removal from wastewater. Compared with the Fe@NC without KOH activation, the pore structure, BET (Brunner-Emmet-Teller) surface area, and oxygen-containing functional group of KOH-activated Fe@NC-KOH-x are dramatically improved, which increases the adsorption and catalytic performance. The Fe@NC-KOH-900/PMS system showed significant BPA removal reactivity across wide pH ranges and low doses of Fe@NC-KOH-900. Interestingly, our findings indicated that the removal effectiveness of BPA improved when PMS was introduced following the saturation adsorption of Fe@NC-KOH-x, as compared to the simultaneous introduction of Fe@NC-KOH-x and PMS. More particularly, through regression analysis, we found that the proportion of reactive species in the Fe@NC-KOH-x/PMS system changes with the increase of pyrolysis temperature, and there was a certain relationship between structure-function and active species in the Fe@NC-KOH-x/PMS system. O-C = O, Fe-N4, C-O, and pyrrolic N in Fe@NC-KOH-x lead to the generation of •OH, and SO4-•, C = O, Fe-N4, and defect are closely related to FeIV = O, and the formation of 1O2 is affected by Fe-N4, graphite N, C = O, and defect. Also, the density functional theory (DFT) calculation and the potential correlation between catalyst active centers and reactive oxygen species indicate that Fe-N4 is the main active site of Fe@NC-KOH-x. These outcomes of the study offer an innovation for enhanced elimination of BPA in wastewater treatment and provide a dynamic understanding of the mechanism of BPA degradation.

Properties of biocoal briquettes from mesoporous coals and rice husk and their effects on environmental pollution

This work assessed some properties and effects of biocoal briquettes on environmental pollution compared with utilising coal alone. A mixture of coal fines and rice husks was prepared, with cassava starch gel as a binder, before compaction in a briquetting machine and drying with a solar dryer. Samples of the coal fines, rice husk, cassava flour and briquettes were analysed for their elemental and oxide concentrations via an energy-dispersive X-ray fluorescence analyser. The heat fuels were analysed for their thermal behaviour via thermogravimetric analyser (TGA), whereas the specific surface area, pore size and pore volume were determined using a Brunner–Emmett–Teller (BET) analyser. The conversion of the tested coals to biocoal briquettes resulted in a reduction in the level of arsenic in the briquettes. Additionally, the sulphur level decreased from 1.96 to 1.11% in the Okobo-Enjema briquettes and from 1.78 to 0.90% in the Onyeama briquettes. However, the levels of manganese increased from 0.04 to 0.22% in the Okobo-Enjema briquettes and from 0.04 to 0.21% in the Onyeama briquettes. Thermogravimetric analysis at different heating rates revealed that derivative weight loss increased with increasing heating rate, from 4.4% at 10 °C/min to 5.5% at 20 °C/min. BET analysis revealed that the briquettes had larger pore diameters, volumes and specific surface areas than did the coal samples. The coal samples have greater propensity to pollute the environment as the amount of potentially hazardous elements in the samples is greater than in their biocoal briquettes.

Photocatalytic degradation of low-concentration gaseous benzene in air via bifunctional tin-doped titanium dioxide catalyst

Benzene, a common volatile organic compound (VOC) detected in indoor environments, poses challenges for its removal because of its stable molecular structure and low-concentration. In this study, we successfully synthesized tin-doped titanium dioxide (Sn-TiO2) using a simple hydrothermal method. Various characterization techniques including X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Brunner–Emmet–Teller (BET) and molecular probes were employed to analyze the phase composition, structure and morphology, as well as photocatalytic properties of TiO2 and Sn-TiO2. The characterization results showed that moderate addition of tin doping not only effectively enhanced the capture ability of benzene molecules but also promoted hydroxyl radicals (·OH) generation, which was further validated by in-situ diffuse reflectance infrared Fourier transform (DRIFT) spectra and density function theory (DFT) calculations. Degradation experiments on gaseous benzene revealed that under 15 W ultraviolet (UV) light irradiation in humid and closed conditions for 60 min, 1 % Sn-TiO2 achieved a benzene degradation efficiency of 93.14 %, with almost complete mineralization. Furthermore, flow system experiments demonstrated efficient decomposition of trace amounts of benzene (∼10 mg/m3) in the air to satisfy emission standards when employing 1 % Sn-TiO2 at a flow rate of 100 L/min.

Synthesis of cobalt- ferrite and zinc oxide metal nanoparticles based-bentonite using SDS and their investigation as catalysts in synthesis of benzylbarbiturocoumarins.

In this research, a suitable and efficient CoFe2O4@ZnO@Bentonite nano-catalyst was designed and synthesized by using zinc oxide (ZnO) and cobalt ferrite (CoFe2O4) nanoparticles and bentonite by microwave irradiation. Characteristics of the synthesized nanocomposite were investigated by Fourier transform infrared (FT-IR), scanning electron microscope (SEM), energy dispersive X-ray (EDX), transmission electron microscope (TEM), X-ray diffraction (XRD), Bruner- Emmett-Teller (BET) and vibrating sample magnetometer (VSM) techniques. The produced catalyst was effectively employed as a supported solid acid catalyst in mildly agitated three-component reactions involving aromatic aldehydes, 4-hydroxycoumarin, and 1,3-dimethyl-barbituric acid in a single pot to produce benzylbarbiturocoumarins. Starting materials were condensed via three C-C bond formation by CoFe2O4@ZnO@Bentonite as an efficient, recyclable, and environmentally safe nanocatalyst to obtain target products. The advantages of this method include using a natural substrate, small amounts of catalyst, aqueous media, performing reactions at ambient temperature, simple separation and purification of products, and good yields with short reaction times.

Synthesis and crystal structure of new Mn (III) complex; a target catalyst for direct conversion of thiols after heterogenization

In this study, we are interested in the synthesizing of a new water-soluble complex of Mn (III) formulated as [Mn(pzo)(dipic)(H2O)2]2·3H2O; hereafter referred to as complex 1 where pzo− = pyrazonate and dipic2− = pyridine-2,6-dicarboxylate, under hydrothermal conditions. The molecular structure of complex 1 is primarily determined by single crystal X-ray diffraction (SC-XRD) which shows two mono-nuclear complexes of Mn (III) with three lattice water molecules. According to SC-XRD, complex 1 crystallizes in space group P1¯ of a triclinic system. The center of Mn (III) is seven-coordinated with a distorted pentagonal-bipyramidal geometry with three oxygen atoms and two nitrogen atoms in the equatorial plane. Two oxygen atoms of two water molecules are coordinated in the axial positions. In addition, the structure of complex 1 has been studied by elemental analysis (CHN), Fourier-transform infrared spectroscopy (FT-IR (, thermogravimetric analysis/differential thermal analysis/differential thermogravimetry (TGA/DTA/DTG). Complex 1 has been immobilized on the silica-coated Fe3O4 nanoparticles to produce an efficient and recyclable heterogeneous catalyst formulated as Fe3O4@SiO2@1; hereafter referred to as catalyst 1. Catalyst 1 was characterized by inductively coupled plasma optical emission spectrometry (ICP-OES), energy-dispersive X-ray spectrometer (EDS), FT-IR, scanning electron micrograph (SEM), powder X-ray diffraction pattern (PXRD), and Brunner-Emmet-Teller (BET). 1 was used as a new heterogeneous catalyst for the oxidative coupling of thiols to their corresponding disulfides using 30 % H2O2. Under optimum reaction conditions, catalyst 1 exhibited high catalytic activity. 1 can be recovered by a magnet and reused for at least 7 consecutive cycles without significant loss of catalytic performance.

Dye wastewater treatment through adsorption-photocatalysis using electroplating sludge-derived NiFe2O4@C catalyst

Electroplating sludge (ES) is classified as HW46 hazardous waste, and its high-value utilization offers superior economic and environmental benefits compared to traditional methods such as thermal treatment, solidification, and landfill. This paper exploits ES's inherent properties while preserving its carbon structure, and a NiFe2O4@C heterojunction catalyst with high adsorption and excellent photocatalytic capabilities is innovatively developed through a novel “one-step” approach. This catalyst is used to activate peroxymonosulfate (PMS) for the degradation of rhodamine B (RhB). Characterization techniques, including scanning electron microscopy (SEM), transmission electron microscopy (TEM), and the Brunner-Emmet-Teller (BET) method, confirm that the NiFe2O4@C prepared under low-oxygen concentration exhibits a remarkably larger surface area and heterogeneous structure. In dark adsorption experiments lasting 60 min, the NiFe2O4@C achieves an adsorption capacity (Qe) of 295.65 mg/kg. During the subsequent 120-minute photoreaction stage, RhB removal efficiency reaches 96.98 %. Quenching experiments reveal that several active radicals (SO4−, ∙OH, and O2−) play a predominant role in RhB degradation, while nonradicals (1O2 and charge transfer) and high-valent metals also contribute to RhB removal. Density functional theory (DFT) calculations predict RhB molecular sites susceptible to attacks by reactive species. The identification of intermediates using liquid chromatography-mass spectrometry (LC-MS), combined with these theoretical insights, confirmed the main degradation pathways of RhB.

Synthesis and characterization of new photocatalyst-based tin (IV) 5, 10, 15, 20-tetrakis (4-benzhydryl benzoate) porphyrin immobilized on Fe3O4 nanoparticles for removal of organic dye from wastewater

In this research, tin (IV) 5,10,15,20-tetrakis 4-benzhydryl benzoate porphyrin (dented as Sn-TBhBP) as a new type of metalloporphyrin was synthesized and immobilized on the surface of Fe3O4 nanoparticles (NPs). The characterization of nanocomposite was carried out by Fourier transform infrared (FT-IR), ultraviolet–visible (UV–vis), X-ray diffraction (XRD), energy dispersive X-ray (EDX), scanning electron microscopy (SEM), fluorescence spectroscopy (FLS), Brunner-Emmett-Teller (BET), transmission electron microscopy (TEM), and differential reflectance spectroscopy (DRS) methods. The catalytic activity of the Sn-TBhBP@Fe3O4 was investigated as a new photocatalyst in the degradation of methylene blue (MB) under visible light irradiation. The results indicated that the maximum efficiency was achieved with a dye concentration of 10 ppm, resulting in a MB degradation rate of 98 % in the presence of Sn-TBhBP@Fe3O4 photocatalyst. Moreover, a prospective mechanism for the developed photocatalytic performance was proposed. The present study demonstrated the possible applications of the Sn-TBhBp@Fe3O4 photocatalyst for the environment issues.

Effect of functionalization and Li-doping methods to hydrogen storage capacities of MWCNTs

One of the most important problems of today has been found alternative and renewable energy sources to fossil fuels. Hydrogen comes to the fore because it is abundant, does not cause environmental problems, and can be stored when not in use. Furthermore, compared to fossil fuels, hydrogen has the highest energy density. However, the most important obstacle to the use of hydrogen energy is its transportation and storage. In this study, the functionalized multi-walled carbon nanotubes were first produced from multi-walled carbon nanotube (MWCNT) by different chemical reactions and, then Li-doped MWCNTs and Li-doped functionalized MWCNTs by solvent and hydrothermal methods. Samples were characterized using Brunner–Emmett–Teller (BET), Fourier transform infrared spectroscopy (FTIR), differential thermal analysis/thermogravimetry (DTA/TG), electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Raman spectroscopy. Finally, the hydrogen storage capacities of all samples were measured using IMI PSI gas storage instrument. New bands belonging to functional groups were observed in the FTIR-ATR spectrum of MWCNT. Functionalized MWCNTs degraded at different temperatures and steps. SEM images showed that the changes in the morphology of MWCNT with functionalization and Li-doping occured. The linear behavior observed in the Nyquist plots showed that the electrochemical process was controlled by ion diffusion. Raman analysis showed that while there was no significant change in the position of the Raman bands. While the BET surface area of MWCNT decreased with functionalization, an increase in its hydrogen storage capacity was observed in general. The hydrothermal method was more effective than the solvent method and functionalization in increasing the hydrogen storage capacity of MWCNT. All samples had higher hydrogen storage capacity at cryogenic temperatures. Li-doped MWCNT by hydrothermal method had the highest hydrogen storage capacity at 80 bar and 77 K, and its storage capacity value was 2.85 wt%. While the isotherm curves obeyed Henry’s law at room temperature, they exhibited multilayer adsorption behavior at cryogenic temperatures. The adsorption process was physical and isotherm type was Type IV.

Preparation and evaluation of GCD-1 lunar regolith simulant based geopolymer activated by solid sodium silicate

In this study, a new lunar regolith simulant, named "GCD-1", was formulated by combining various minerals, such as anorthite, albite, pyroxene, ilmenite, slag, and fly ash. Through X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD) analysis, it was verified that the main mineral composition of GCD-1 was basically the same as that of the lunar soil at the Apollo 14 landing site, in which the deviation in the main compound (i.e., SiO2 and Al2O3) was within 0.5%. Furthermore, GCD-1 based geopolymer was prepared by the one-part method, which was a mixture of solid GCD-1 precursor, solid sodium silicate (SS) activator, and water. The average daytime temperature at the lunar equator, which was calculated to be 60°C, was set as the curing temperature for the GCD-1 based geopolymer. The strength development of the GCD-1 based geopolymer was then characterized by unconfined compressive strength (UCS) for 3, 7, and 12 curing days to consider the effectiveness of the factors (solid SS to lunar regolith simulant [S/L] and water to binder ratio [W/B]). The micro-analysis tests including scanning electron microscope-energy dispersive spectrometer (SEM-EDS), mercury intrusion porosimetry (MIP), and brunner-emmet-teller (BET), were further conducted to investigate the microstructural development of the GCD-1 based geopolymer. Results showed that the increase of the W/B ratio in the GCD-1 based geopolymer tended to increase the total porosity of the sample, thereby inducing a lower UCS. At the same time, for a fixed W/B ratio, the higher S/L ratio had a certain inhibition effect on the hydration reaction, which caused the reduction in the UCS of the sample. The highest UCS of the GCD-1 based geopolymer reaching 30.54 MPa, was achieved under the simulated lunar equatorial daytime temperature for 12 days with W/B and S/L ratios set at 0.25 and 0.18, respectively. Microstructure and mineralogy analyses indicated that the hydrated sodium aluminosilicate (N-A-S-H) gels contributed to reducing the sample's porosity, thereby enhancing the UCS. The relationship between the UCS and total porosity of GCD-1 based geopolymer was then derived. The results of the current study are crucial for lunar base construction with in-situ resources.

Electrochemical performance of chemically treated pyrolytic carbon black from waste car tyres

Pyrolytic carbon black (CBp) is a solid by-product of tyre pyrolysis that contains various contaminants from the tyre additives. These contaminants limit the use of CBp as a carbon source for energy storage applications such as supercapacitors. This study aims to improve the physicochemical, morphological, and electrochemical properties of CBp by applying different chemical treatments and activation methods. The chemical treatments include acid (HCl), base (NaOH), acid-base (HCl/NaOH), and desulphurization (NaOH in xylene) processes to remove impurities such as sulphur, zinc, and silicon. The treated CBp samples are then activated by KOH impregnation technique to increase the surface area and porosity. The characterizations of the treated CBp samples are performed using Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDX), X-ray Diffraction (XRD), and Brunner Emmett Teller (BET). The electrochemical performance of the treated CBp samples are evaluated using galvanostatic charge-discharge (GCD), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The results show that the chemical treatments significantly reduce the impurity levels and enhance the electrochemical performance of CBp. The desulphurized CBp sample exhibits the highest specific capacitance of 218 F/g among the treated CBp samples. The findings of this study suggest that CBp can be effectively utilized as a potential carbon source for supercapacitor electrodes by applying suitable chemical treatments and activation methods. This will create a circular economy to valorize CBp.

Ultrasonication Improves the Flotation of Coal Gasification Fine Slag Residue

Coal gasification fine slag (CGFS) is a significant source of solid waste requiring improved treatment methods. This study primarily investigates the mechanism of ultrasonic treatment in optimising flotation-based decarbonization of CGFS and its impact on CGFS modified with surfactants. The objective is to maximise the carbon ash separation effect to support the clean and efficient utilisation of CGFS. Flotation experiments revealed optimal conditions at an ultrasonication power of 180 W for 2 min and a slurry concentration of 60 g/L, resulting in a residual ash content of 82.59%. Particle size analysis, scanning electron microscopy (SEM), and Brunner−Emmet−Teller (BET) measurements demonstrate the efficacy of ultrasound in extracting inorganic minerals from the surface and pores of residual carbon, consequently reducing both pore and particle sizes. Fourier transform infrared spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) analyses indicate alterations in the surface chemistry of CGFS induced by ultrasound treatment. The content of hydrophilic groups decreased from 31.64% to 29.88%, whereas the COO- group content decreased from 13.13% to 8.43%, consequently enhancing hydrophobicity. Adsorption experiments demonstrate an increase in surfactant adsorption capacity following ultrasonic treatment. Furthermore, ultrasonic treatment facilitates the desorption of surfactants previously adsorbed onto the surfaces of CGFS residue. Therefore, optimal flotation is obtained by applying ultrasonic pretreatment to CGFS before adding flotation chemicals. Upon the addition of Polysorbate (Tween-80), the residual ash content increased 90.17%.

Aspects of superior photocatalytic dye degradation and adsorption efficiency of reduced graphene oxide multiwalled carbon nanotubes with modified ZnO-Al2O3 nanocomposites

Due to the poor effectiveness of nanomaterials, the elimination of hazardous textile dyes from wastewater is quite challenging. A wide range of low-cost, hybrid, and highly effective nanomaterials have attracted much research for their potential in wastewater treatment. Herein, ZnO-Al2O3 nanoparticles were successfully grafted on reduced graphene oxide/multiwalled carbon nanotubes (ZnO-Al2O3-rGO/MWCNT) via the hydrothermal process. This nanohybrid material has been characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunner Emmet Teller (BET) analysis. ZnO-Al2O3-rGO/MWCNT has degraded 30 ppm Congo red dye to 90% within 1 h, while 20 ppm rose Bengal dye to 80% within 1.5 h. The kinetics of degradation for both these dyes is followed well by the pseudo-first-order model. Furthermore, ZnO-Al2O3-rGO/MWCNT was explored for the adsorption of Sudan III and displayed an outstanding removal capacity (220 mg g−1) compared with bare catalyst ZnO−Al2O3 (72 mg g−1). The sorption of Sudan III dye onto the adsorbent is spontaneous endothermic and follows pseudo−second−order kinetics and Langmuir isotherm models. Experiments using radical trapping have shown that hydroxyl radicals are the principal reactive intermediates in the photoexcitation process. The desorption and regeneration of as−prepared nanocomposite are also assessed.

Sewage Sludge-Derived Biochar and Its Potential for Removal of Ammonium Nitrogen and Phosphorus from Filtrate Generated during Dewatering of Digested Sludge

Utilizing waste, such as sewage sludge, into biochar fits the circular economy concept. It maximizes the reuse and recycling of waste materials in the wastewater treatment plant. The experiments were conducted to assess: (1) the impact of the temperature on the properties of biochar from sewage sludge (400 °C, 500 °C, 600 °C, 700 °C); (2) how the physical activation (CO2, hot water) or chemical modification using (MgCl2, KOH) could affect the removal of ammonia nitrogen and phosphorus from filtrate collected from sludge dewatering filter belts or synthetic solution, wherein the concentration of ammonium nitrogen and phosphorus were similar to the filtrate. Based on the Brunner–Emmett–Teller (BET) surface and the type and concentration of surface functional groups for the second stage, biochar was selected and produced at 500 °C. The modification of biochar had a statistically significant effect on removing nitrogen and phosphorus from the media. The best results were obtained for biochar modified with potassium hydroxide. For this trial, 15%/17% (filtrate/synthetic model solution) and 72%/86% nitrogen and phosphorus removal, respectively, were achieved.

Introducing a novel catalyst for efficient conversion of CO2 into syngas through reverse-water-gas-shift (RWGS) reactions based on highly mesoporous structures MCM-41: Influence of the Fe incorporation

The RWGS is the first step in CO2 hydrogenation. This process converts CO2 into valuable compounds, such as methanol, to address the global issue of CO2 emissions. In this research, the performance of a Cu-Fe bimetallic catalyst mounted onto MCM-41 support in RWGS was investigated. Our results demonstrate that MCM-41′s high specific surface area is advantageous for dispersing active metals and preventing their sintering. The Cu-Fe supported on MCM-41 samples are characterized by Scanning Electron Microscopy (SEM), ex situ X-ray Diffraction (XRD), Brunner–Emmet–Teller (BET), and Temperature Programmed Reduction (TPR). In order to investigate the catalytic activity, key variables including a temperature range of 400–600 °C, different H2/CO2 ratios, and various gas hourly space velocities (GHSV) at atmospheric pressure were assessed. In this study, excellent CO2 conversion was attained at a high GHSV (96,000 ml g-1h−1), which is advantageous for the design of smaller reactor volumes. In comparison to industrial Copper-Zinc catalysts and iron-free copper-supported MCM-41 catalysts, which suffer from a high sintering rate at temperatures above 300 °C, adding Iron (Fe) to the copper could increase the catalyst's activity and stability in terms of CO2 conversion and CO selectivity due to the formation of a Cu-Fe alloy. The novelty of this study lies in the assessment of the benefits afforded by bimetallic Cu-Fe catalysts in conjunction with high surface area MCM-41. Also, three different ratios of Cu-Fe (10-1, 7-1, 4-1) were considered for our experiments. The Cu-Fe = 10-1 ratio reached the highest CO2 conversion and CO selectivity value in 600 °C with amounts of 49 % and 99.7 %, respectively.

Structural and antibacterial properties of copper oxide nanoparticles: a study on the effect of calcination temperature

Nanoparticles of copper oxide were synthesized by the simple precipitation method. The influence of calcination temperature on the structural characteristics and antibacterial activity of the nanoparticles were evaluated. The nanoparticles were analyzed by Bruner-Emmett-Teller (BET) surface area and pore size analyzer, x-ray diffraction, transmission electron microscope and scanning electron microscope. The findings demonstrated the formation of copper oxide nanoparticles showing a monoclinic phase. Before calcination, the nanoparticles showed a high BET surface area with rod shape morphology and size range between 18–70 nm and after calcination, irregular spherical-like morphology with size range of 20–200 nm was observed. However, it was evident that the BET surface area decreased gradually with increasing calcination temperature, while the nanoparticle size increased forming an irregular spherical shape. Subsequently, the copper oxide nanoparticles demonstrated that they are highly effective for bacteria inactivation. The inactivation activity was found to be more effective with uncalcined nanoparticles than with calcined nanoparticles. This was due to the large nanoparticle sizes and the decrease in surface area obtained after calcination. Thus, it was noted that calcination of the as-prepared nanoparticles significantly affects the structural and antibacterial properties. Hence, for antibacterial application, calcination was not necessary as the nanoparticles showed excellent antibacterial results.