Synergistically active Fe3O4 magnetic and EDTA modified cellulose cotton fabric using chemical method and their effective pollutants removal ability from wastewater.

A unique combination of cotton fabric (CF) with a mixture of EDTA and APTES Fe3O4 magnetic particles was developed and utilized for the first time as an adsorbent for removing pollutants from wastewater. Initially, Fe3O4 was synthesized using the co-precipitation method. Further, the surface of Fe3O4 was modified by introducing amino functional groups through a reaction with APTES, resulting in Fe3O4-NH2. Following this, the surface of carbon fiber (CF) was altered using ethylenediaminetetraacetic acid (EDTA) to create CF@EDTA. Through the use of EDC-HCl and NHS, Fe3O4-NH2 was attached to the surface of CF@EDTA, resulting in the final product CF@EDTA/Fe3O4. Subsequently, the prepared CF@EDTA/Fe3O4 was utilized to adsorb metal pollutants from wastewater, with a thorough analysis conducted using various characterization techniques including FTIR, SEM, EDX, XRD, VSM, and XPS to study the materials. The study specifically aimed to assess the adsorption performance of our cotton-based material towards As(III) and Cr3+ metal ions. The pH study was also performed. Results indicated that the material exhibited an adsorption capacity of approximately 714 mg/g for As(III) ions and 708 mg/g for Cr3+ ions. The Langmuir and Freundlich models, as well as pseudo-first and second-order models were also analyzed. The Langmuir and pseudo-second-order models were found to best fit the data. In terms of regeneration and reusability, the materials showed straightforward regeneration and recyclability for up to 15 cycles. The remarkable adsorption capacity, combined with the unique blend of cotton and Fe3O4 magnet, along with its recyclability, positions our material CF@EDTA/Fe3O4 as a promising contender for wastewater treatment and other significant areas in water research.

Synthesis of cellulose cotton-based UiO-66 MOFs for the removal of rhodamine B and Pb(II) metal ions from contaminated wastewater.

The presence of pollutants in drinking water has become a significant concern recently. Various substances, including activated carbon, membranes, biochar, etc., are used to remove these pollutants. In the present study, a new composite comprising cotton fabric and a mixture of Metal-Organic Frameworks (MOFs) was synthesized and used as an adsorbent for eliminating pollutants from wastewater. At first, the UiO-66 MOFs were prepared by a simple method of reacting Zirconium (IV) chloride (ZrCl4) and p-Phthalic acid (PTA) after successful preparation of UiO-66 then modified its surface with amino functional groups by reacting with APTES to obtain UiO-66-NH2. Moreover, the cellulose cotton fabric (CF) surface was modified with Polydopamine (PDA) and obtained CF@PDA. Further, with the help of EDC-HCl and NHS, the UiO-66-NH2 grafted on the surface of the CF@PDA and finally obtained CF@PDA/UiO-66-NH2. In addition, the adsorption study was performed toward RhB dye and Pb(II) metal ion pollutants. The maximum adsorption toward RhB dye was 68.5 mg/g, while toward Pb(II) metal ions was 65 mg/g. In addition, the kinetic study was also conducted and the result favoured the Pseudo-second order kinetic study. The adsorption isotherm was also studied and the Langmuir model was more fitted as compared with the Freundlich model. Moreover, the material has excellent regeneration and recycling ability after ten cycles. The significant adsorption ability, the novel combination of cotton and MOFs, and the recycling feature make our material CF@PDA/UiO-66-NH2 a promising potential absorbent material for wastewater treatment and even in other important areas of water research.

High-performance Cu/Mn modified ceramsite as a persulfate activator to degrade oxytetracycline in batch Erlenmeyer flask and continuous-flow fixed-bed column systems: An exploration of its practicability and non-radical mechanisms.

Persulfate non-radical oxidation have excellent catalytic capability for degrading specific contaminants in complicated water environments. Nevertheless, the preparation of high-performance activators and their application in actual water treatment in continuous flow mode are still scarce and unsatisfactory. In this work, copper-, manganese-, and copper/manganese-doped ceramsites (Cu-C, Mn-C and Cu/Mn-C), successfully fabricated through a facile impregnation-calcination approach, were characterized and evaluated for their performance to activate potassium peroxydisulfate (PDS) and degrade oxytetracycline (OTC) under different pH, ceramsite dosages, and PDS dosages. Compared with Cu-C and Mn-C, Cu/Mn-C showed the highest OTC degradation rate (0.0264 min-1) via activating PDS with an OTC removal efficiency of 98.2% in 240 min at an initial OTC concentration of 40 mg/L. The removal efficiency of OTC by Cu/Mn-C only decreased to 92.8% after 5 cycles; the activating ability of the used Cu/Mn-C was almost completely recovered through 2 h of calcination at 500 °C. The results of electron paramagnetic resonance and radical quenching suggest that singlet oxygen (1O2) was unveiled to be the dominant reactive oxygen species (ROS) for contaminant degradation, originating from the regrouping of superoxide ions or reduction of active Cu/Mn sites. Synergies between Cu and Mn species to enhance ROS yield were the primary activating mechanisms. Six possible routes of OTC decomposition were inferred. Additionally, Cu/Mn-C behaved excellently in treating an actual wastewater using a continuous flow fixed-bed reactor. It is believed that this novel Cu/Mn-C/PDS system may create a fresh path to design effective and cheap metal-ceramsite hybrid activators for degrading recalcitrant contaminants in the actual application process.

The Synergistic Inhibitions of Tungstate and Molybdate Anions on Pitting Corrosion Initiation for Q235 Carbon Steel in Chloride Solution.

In this work, the synergistic inhibitions of tungstate (WO42-) and molybdate (MoO42-) anions, including role and mechanism, on the initiation of pitting corrosion (PC) for Q235 carbon steel in chloride (Cl-) solution were investigated with electrochemical and surface techniques. The pitting potential (Ep) of the Q235 carbon steel in WO42- + MoO42- + Cl- solution was more positive than that in WO42- + Cl- or MoO42- + Cl- solution; at each Ep, both peak potential and affected region of active pitting sites in WO42- + MoO42- + Cl- solution were smaller than those in WO42- + Cl- or MoO42- + Cl- solution. WO42- and MoO42- showed a synergistic role to inhibit the PC initiation of the Q235 carbon steel in Cl- solution, whose mechanism was mainly attributed to the influences of two anions on passive film. Besides iron oxides and iron hydroxides, the passive film of the Q235 carbon steel formed in WO42- + Cl-, MoO42- + Cl-, or WO42- + MoO42- + Cl- solution was also composed of FeWO4 plus Fe2(WO4)3, Fe2(MoO4)3, or Fe2(WO4)3 plus Fe2(MoO4)3, respectively. The film resistance and the defect quantity for Fe2(WO4)3 plus Fe2(MoO4)3 film were larger and smaller than those for FeWO4 plus Fe2(WO4)3 film and Fe2(MoO4)3 film, respectively; for the inhibition of PC initiation, Fe2(WO4)3 plus Fe2(MoO4)3 film provided better corrosion resistance to Q235 carbon steel than FeWO4 plus Fe2(WO4)3 film and Fe2(MoO4)3 film did.

Comparative Toxicity, Biodistribution and Excretion of Ultra-Small Gold Nanoclusters with Different Emission Wavelengths.

The exponentially increased use of gold nanoclusters in diagnosis and treatment has raised serious concern about their potential threat to living organisms. However, the mechanisms of toxicity of gold nanoclusters in vitro and in vivo remain poorly understood. In this work, comparative toxicity studies, including biodistribution and excretion, were carried out with mildly and chemically synthesized ultra-small L-histidine-protected and bovine serum albumin (BSA)-protected gold nanoclusters in an all-aqueous process. These nanoclusters did not induce a remarkable impact on cell viability, even at relatively high concentrations (100 µg/mL). The haemolytic assay demonstrated that the gold nanoclusters could not destroy blood cell at 600 µg/mL. After intravenous injection with mice, the biocompatibility, biodistribution, and excretion were determined. Quantitative analysis results showed that accumulation varied in the liver, spleen, kidney, and lung, though primarily in the liver and spleen. They were excreted in urine and faeces, but mainly excreted through urine. In our study, no obvious abnormalities were found in body weight, behavioral changes, blood and serum biochemical indicators, and histopathology. These findings suggested that both gold nanoclusters showed similar effects in vivo and were safe and biocompatible, laying the foundation for safe biomedical application in the future.

Probing toluene catalytic removal mechanism over supported Pt nano- and single-atom-catalyst.

Commercial TiO2 supported 0.20 wt% Pt catalyst is obtained via the molten salt method, and both Pt nanoparticles and single atom Pt sites are observed. It exhibits high catalytic performance for toluene oxidation, with T50 and T90 being 173 and 183 °C, respectively. Reaction intermediates including benzene, p-xylene, o-xylene, benzaldehyde, phthalic acid, maleic anhydride, itaconic anhydride, acetone, and acetic acid, are detected during toluene oxidation. On this basis, likely toluene combustion reaction pathway is provided. Benzaldehyde is the most stable surface intermediate, and its oxidation can be rate-limiting for the entire toluene oxidation reaction. 2-10.0 vol% H2O slightly inhibits the reaction by competing surface sites with the reactant, while it does not poison the catalyst. 2.5-10.0 vol% CO2 slightly poisons the catalyst by surface carbonate formation, whereas 50 ppm SO2 severely poisons the catalyst by sulfite/sulfate formation.

Ultralow Loading of Silver Nanoparticles on Mn2O3 Nanowires Derived with Molten Salts: A High-Efficiency Catalyst for the Oxidative Removal of Toluene.

Using a mixture of NaNO3 and NaF as molten salt and MnSO4 and AgNO3 as metal precursors, 0.13 wt % Ag/Mn2O3 nanowires (0.13Ag/Mn2O3-ms) were fabricated after calcination at 420 °C for 2 h. Compared to the counterparts derived via the impregnation and poly(vinyl alcohol)-protected reduction routes as well as the bulk Mn2O3-supported silver catalyst, 0.13Ag/Mn2O3-ms exhibited a much higher catalytic activity for toluene oxidation. At a toluene/oxygen molar ratio of 1/400 and a space velocity of 40,000 mL/(g h), toluene could be completely oxidized into CO2 and H2O at 220 °C over the 0.13Ag/Mn2O3-ms catalyst. Furthermore, the toluene consumption rate per gram of noble metal over 0.13Ag/Mn2O3-ms was dozens of times as high as that over the supported Au or AuPd alloy catalysts reported in our previous works. It is concluded that the excellent catalytic activity of 0.13Ag/Mn2O3-ms was associated with its high dispersion of silver nanoparticles on the surface of Mn2O3 nanowires and good low-temperature reducibility. Due to high efficiency, good stability, low cost, and convenient preparation, 0.13Ag/Mn2O3-ms is a promising catalyst for the practical removal of volatile organic compounds.

Ce(0.6)Zr(0.3)Y(0.1)O(2) nanorod supported gold and palladium alloy nanoparticles: high-performance catalysts for toluene oxidation.

The Ce0.6Zr0.3Y0.1O2 (CZY) nanorods and their supported gold and palladium alloy (zAuxPdy/CZY; z = 0.80-0.93 wt%; x or y = 0, 1, 2) nanoparticles (NPs) were prepared using the cetyltrimethyl ammonium bromide-assisted hydrothermal and polyvinyl alcohol-protected reduction methods, respectively. Physicochemical properties of the samples were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the oxidation of toluene. It is shown that the CZY in zAuxPdy/CZY was cubic in crystal structure, surface areas of CZY and zAuxPdy/CZY were in the range 68-77 m(2) g(-1), and the Au-Pd NPs with a size of 4.6-5.6 nm were highly dispersed on the surface of CZY nanorods. Among all the samples, 0.90Au1Pd2/CZY possessed the highest adsorbed oxygen concentration and the best low-temperature reducibility, and performed the best: T50% and T90% (temperatures required for achieving toluene conversions of 50 and 90%) were 190 and 218 °C at a space velocity of 20 000 mL (g h)(-1), respectively. The partial deactivation due to water vapor introduction was reversible. The active sites might be the surface oxygen vacancies on CZY, oxidized noble metal NPs, and/or interfaces between noble metal NPs and CZY. The apparent activation energies (37-43 kJ mol(-1)) obtained over 0.90-0.93AuxPdy/CZY were much lower than that (88 kJ mol(-1)) obtained over CZY for toluene oxidation. It is concluded that the excellent catalytic performance of 0.90Au1Pd2/CZY was associated with its high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Au-Pd NPs and CZY nanorods as well as good dispersion of Au-Pd NPs.

Preparation and high catalytic performance of Au/3DOM Mn2O3 for the oxidation of carbon monoxide and toluene.

Three-dimensionally ordered macroporous (3DOM) Mn2O3 and its supported gold (xAu/3DOM Mn2O3, x=1.9-7.5wt%) nanocatalysts were prepared using the polymethyl methacrylate-templating and polyvinyl alcohol-protected reduction methods, respectively. The 3DOM Mn2O3 and xAu/3DOM Mn2O3 samples exhibited a surface area of 34-38m(2)/g. The Au nanoparticles (NPs) with a size of 3.0-3.5nm were uniformly dispersed on the skeletons of 3DOM Mn2O3. The 5.8Au/3DOM Mn2O3 sample performed the best, giving the T90% (the temperature required for a conversion of 90%) of -15°C at space velocity (SV)=20,000mL/(gh) for CO oxidation and 244°C at SV=40,000mL/(gh) for toluene oxidation. The apparent activation energies (30 and 54kJ/mol) over 5.8Au/3DOM Mn2O3 were much lower than those (80 and 95kJ/mol) over 3DOM Mn2O3 for CO and toluene oxidation, respectively. The effects of SV, water vapor, CO2, and SO2 on catalytic activity were also examined. It is concluded that the excellent catalytic performance of 5.8Au/3DOM Mn2O3 was associated with its high oxygen adspecies concentration, good low-temperature reducibility, and strong interaction between Au NPs and 3DOM Mn2O3 as well as high-quality porous architecture.

Porous cube-aggregated Co3O4 microsphere-supported gold nanoparticles for oxidation of carbon monoxide and toluene.

Porous cube-aggregated monodisperse Co3O4 microspheres and their supported gold (xAu/Co3O4 microsphere, x=1.6-7.4 wt %) nanoparticles (NPs) were fabricated using the glycerol-assisted solvothermal and polyvinyl alcohol-protected reduction methods. Physicochemical properties of the materials were characterized by means of numerous analytical techniques, and their catalytic activities were evaluated for the oxidation of toluene and CO. It is shown that the cubic Co3O4 microspheres were composed of aggregated cubes with a porous structure. The gold NPs with a size of 3.2-3.9 nm were uniformly deposited on the surface of Co3O4 microspheres. Among the Co3O4 microsphere and xAu/Co3O4 microsphere samples, the 7.4Au/Co3O4 microspheres performed the best, giving T90 % values (the temperature required for achieving a CO or toluene conversion of 90 % at a weight hourly space velocity of 20 000 mL g(-1) h(-1)) of -8 and 250 °C for CO and toluene oxidation, respectively. In the case of 3.0 vol % water vapor introduction, a positive effect on CO oxidation and a small negative effect on toluene oxidation were observed over the 7.4Au/Co3O4 microsphere sample. The apparent activation energies obtained over the xAu/Co3O4 microsphere samples were in the ranges of 40.7-53.6 kJ mol(-1) for toluene oxidation and 21.6-34.6 kJ mol(-1) for CO oxidation. It is concluded that the higher oxygen adspecies concentration, better low-temperature reducibility, and stronger interaction between gold NPs and Co3O4 as well as the porous microspherical structure were responsible for the excellent catalytic performance of 7.4Au/Co3O4 microsphere.

Au/3DOM Co3O4: highly active nanocatalysts for the oxidation of carbon monoxide and toluene.

Three-dimensionally ordered macroporous Co3O4 (3DOM Co3O4) and its supported gold (xAu/3DOM Co3O4, x = 1.1-8.4 wt%) nanocatalysts were prepared using the polymethyl methacrylate-templating and bubble-assisted polyvinyl alcohol-protected reduction methods, respectively. The 3DOM Co3O4 and xAu/3DOM Co3O4 samples exhibited a surface area of 22-27 m(2) g(-1). The Au nanoparticles with a size of 2.4-3.7 nm were uniformly deposited on the macropore walls of 3DOM Co3O4. There were good correlations of oxygen adspecies concentration and low-temperature reducibility with catalytic activity of the sample for CO and toluene oxidation. Among 3DOM Co3O4 and xAu/3DOM Co3O4, the 6.5Au/3DOM Co3O4 sample performed the best, giving a T90% (the temperature required for achieving a conversion of 90%) of -35 °C at a space velocity of 20 000 mL g(-1) h(-1) for CO oxidation and 256 °C at a space velocity of 40 000 mL g(-1) h(-1) for toluene oxidation. The effect of water vapor was more significant in toluene oxidation than in CO oxidation. The apparent activation energies (26 and 74 kJ mol(-1)) over 6.5Au/3DOM Co3O4 were lower than those (34 and 113 kJ mol(-1)) over 3DOM Co3O4 for CO and toluene oxidation, respectively. It is concluded that the higher oxygen adspecies concentration, better low-temperature reducibility, and strong interaction between Au and 3DOM Co3O4 were responsible for the excellent catalytic performance of 6.5Au/3DOM Co3O4.

Controlled generation of uniform spherical LaMnO3, LaCoO3, Mn2O3, and Co3O4 nanoparticles and their high catalytic performance for carbon monoxide and toluene oxidation.

Uniform hollow spherical rhombohedral LaMO3 and solid spherical cubic MOx (M = Mn and Co) NPs were fabricated using the PMMA-templating strategy. Hollow spherical LaMO3 and solid spherical MOx NPs possessed surface areas of 21-33 and 21-24 m(2)/g, respectively. There were larger amounts of surface-adsorbed oxygen species and better low-temperature reducibility on/of the hollow spherical LaMO3 samples than on/of the solid spherical MOx samples. Hollow spherical LaMO3 and solid spherical MOx samples outperformed their nanosized counterparts for oxidation of CO and toluene, with the best catalytic activity being achieved over the solid spherical Co3O4 sample for CO oxidation (T50% = 81 °C and T90% = 109 °C) at space velocity = 10,000 mL/(g h) and the hollow spherical LaCoO3 sample for toluene oxidation (T50% = 220 °C and T90% = 237 °C) at space velocity = 20,000 mL/(g h). It is concluded that the higher surface areas and oxygen adspecies concentrations and better low-temperature reducibility are responsible for the excellent catalytic performance of the hollow spherical LaCoO3 and solid spherical Co3O4 NPs. We believe that the PMMA-templating strategy provides an effective route to prepare uniform perovskite-type oxide and transition-metal oxide NPs.