Zero-valent Copper Research Articles

Synergy Effect between Facet and Zero-Valent Copper for Selectivity Photocatalytic Methane Formation from CO2

Synergy Effect between Facet and Zero-Valent Copper for Selectivity Photocatalytic Methane Formation from CO₂

A novel way of activating peroxysulfate by zero-valent copper and ferroferric oxide co-modified biochar to remove bisphenol A in aqueous solution: Performance, mechanism and potential toxicity

In view of the highly demanding in heterogeneous catalysts with intensive activity and stability in AOPs based water pollution treatment, a magnetically separable Cu0-Fe3O4@Biochar composite was prepared by citric acid combustion method and utilized to remove bisphenol A (BPA) in aqueous solution at a broad pH range via activation of peroxymonosulfate (PMS). A remarkable synergetic effect was observed between Cu0-Fe3O4 and Biochar. 5 mM NaHCO3 could increase the stability of Cu0-Fe3O4@Biochar(65%) and catalytic activity as well. Indicating by EPR and quenching experiment results, singlet oxygen which may come from the lattice oxygen of the composite based on XPS analysis was the main active species in the degradation system other than hydroxyl radicals and sulfate radicals. In accordance with the degradation efficiency results, electrochemical analysis verified that the capability of electron transfer was enhanced markedly once coupling Cu0-Fe3O4 and Biochar. The acute and chronic toxicities of intermediates produced were evaluated indicating dramatic reduction in toxic.

Highly selective and durable of monodispersed metal atoms in ammonia production

Electrochemical synthesis of ammonia under environmental conditions is a beautiful dream of scientists and entrepreneurs, and has been regarded as an ideal alternative strategy to traditional Haber-Bosch process. In this study of synthetic ammonia, we rationally consider the defects of the current catalysts and propose innovative preparation methods. For the first time, we synthesized independent, highly dispersed zero-valent copper atomic catalysts which were uniformly distributed on 2D graphdiyne (Cu0/GDYNA). This catalyst was used for electrochemical NO3--to-NH3 conversion. After dozens of rigorous experiments, an exciting result are presented that the Cu0/GDYNA showed the highest NH3 yield rate (YNH3) of 15.45 mmol h−1 cm−2 and the maximal ammonia Faradaic efficiency (FE) of 81.25% at ambient temperatures and pressures. Furthermore, the Cu0/GDYNA could continuously catalyze the ammonia production over a consecutive 36-cycle electrolysis with almost no loss of catalytic performance. The excellent electrocatalytic properties of atomic catalysts show that the incomplete charge transfer behavior between metal atoms and GDY produces continuous high activity, promotes ammonia production rapidly selectively suppresses inhibitory by-products, and achieves ultra-high ammonia yield and FE.

Novel functionalized cellulose derivatives fabricated with Cu nanoparticles: synthesis, characterization and degradation of organic pollutants

In this study, microcrystalline cellulose (MCC) was modified to oxidized cellulose (OC), 6-deoxycellulose hydrazide and 6-deoxycellulose (N,N-diethyl)amine (MCC-Hyd and MCC-DEM) derivatives and employed as supporting material for the synthesis of copper nanoparticles (NPs). Copper ions from aqueous solution were adsorbed and then reduced to zero valent copper (ZVC) NPs using sodium borohydride on films of prepared derivatives. The characterization of prepared derivatives and Cu NPs embedded films was performed using Fourier Transform Infrared Spectroscopy, Elemental analysis, X-ray diffraction, Scanning Electron Microscopy, X-ray photoelectron spectroscopy and Nuclear Magnetic Resonance spectroscopy. Ultraviolet/Visible (UV–VIS) spectroscopy was performed for the degradation studies of 4-nitrophenol (4-NP) and various azo dyes viz. Congo Red, Methylene Blue, and Methyl orange. Results revealed that all the films showed degradation only in the presence of ZVC NPs. Oxidized cellulose, MCC-Hyd and MCC-DEM showed excellent degradation efficiencies (> 85%) in all the cases. Our findings revealed that MCC derivatives could be efficient and renewable candidates for removal of water pollutants in future.Graphical abstract

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

Octahedron of Zero-Valent and Mono-Valent Copper Anchored on Nitrogen Doping Porous Carbon to Enhance Heterogeneous Electro-Fenton Like Activity

One-electron bonds in copper-aluminum and copper-gallium complexes.

Odd-electron bonds have unique electronic structures and are often encountered as transiently stable, homonuclear species. In this study, a pair of copper complexes supported by Group 13 metalloligands, M[N((o-C6H4)NCH2PiPr2)3] (M = Al or Ga), featuring two-center/one-electron (2c/1e) σ-bonds were synthesized by one-electron reduction of the corresponding Cu(i) ⇢ M(III) counterparts. The copper bimetallic complexes were investigated by X-ray diffraction, cyclic voltammetry, electron paramagnetic spectroscopy, and density functional theory calculations. The combined experimental and theoretical data corroborate that the unpaired spin is delocalized across Cu, M, and ancillary atoms, and the singly occupied molecular orbital (SOMO) corresponds to a σ-(Cu–M) bond involving the Cu 4pz and M ns/npz atomic orbitals. Collectively, the data suggest the covalent nature of these interactions, which represent the first examples of odd-electron σ-bonds for the heavier Group 13 elements Al and Ga.

Dealloyed nanoporous copper as a highly active catalyst in Fenton-like reaction for degradation of organic pollutants

Copper-based catalysts for persulfate-based oxidation are desired due to the low toxicity. Herein, nanoporous copper materials were fabricated by dealloying the aluminum-copper (Al-Cu) alloys. Bicontinuous interpenetrating ligament–channel structures containing zero-valent copper (Cu0) network with trace Cu2O on the surface were obtained by adjusting the dealloying conditions. The as-dealloyed nanoporous copper catalysts exhibited superior catalytic performances in peroxymonosulfate (PMS) activation towards the degradation of bisphenol A (BPA), compared with the commercial Cu0 and Cu2O nanoparticles or counterparts prepared by liquid precipitation methods. The unique structures of nanoporous copper provide more exposure of active sites and pathways for mass transfer. In addition, the copper network with good conductivity favors the electron transfer, and the ligaments with high-density low-coordinated sites are ready to interact with PMS. Assisted by the simulated sunlight, the degradation efficiency was greatly improved through photochemical oxidation, due to the synergistic effect of light irradiation and PMS. The free hydroxyl (•OH) and sulfate (SO4•−) radicals mainly contributed to the degradation of BPA in the chemical oxidation, while •OH, SO4•− and singlet oxygen (1O2) dominated the decomposition in the photochemical reaction. This study suggests that dealloying is an effective method for fabricating catalysts for persulfate-based oxidation, providing new insight in developing highly active catalysts for wastewater purification.

Strong degradation of orange II by activation of peroxymonosulfate using combination of ferrous ion and zero-valent copper

• Fe(II) coupled with ZVC boosted PMS to degrade orange II. • Fe(II)/ZVC/PMS system exhibited high removal of TOC for orange II. • Fe(III)/Fe(II) cycle was promoted by Cu(I) and ZVC. • Cu(III), OH and SO 4 − were the main oxidants in the Fe(II)/ZVC/PMS system. • Orange II in actual sample was greatly degraded in Fe(II)/ZVC/PMS system. Zero-valent copper activated peroxymonosulfate (ZVC/PMS) system was widely used to degrade refractory contaminants due to being highly effective. However, the low reactivity and easy dismutation of cuprous species (Cu(I)) in acid condition limited its efficiency. In our study, ZVC coupled with ferrous ion (Fe(II)) promoted PMS to degrade orange II. Multiple oxidants including Cu(III), OH and SO 4 − made main contribution on orange II degradation in the Fe(II)/ZVC/PMS system. In the Fe(II)/ZVC/PMS system, ZVC generated Cu(I) by H + corrosion and PMS oxidation, and Cu(I) reacted with oxygen producing hydrogen peroxide. Then, Fe(II) and Cu(I) catalyzed hydrogen peroxide and PMS to generate Cu(III), OH and SO 4 − , and thereinto Fe(III) was reduced to Fe(II) by ZVC and Cu(I). In the Fe(II)/ZVC/PMS system, water matrix including humic acid, sulfate and nitrate had no significant impact on orange II degradation, while chloride restrained the degradation of orange II. The Fe(II)/ZVC/PMS system exhibited great degradation for orange II in tap water, lake water and well water. Additionally, the Fe(II)/ZVC/PMS system degraded more than 90% of methyl orange, rhodamine B, acetaminophen, ibuprofen, propranolol and diclofenac. Through adjusting the final reaction solution to pH 8.5 and subsiding, the discharge of total copper met the II-level environmental quality standards for surface water in China (1 mg/L). Hence, the study provided a promising method to induce PMS for enhanced degradation of contaminants.

Performance of nZVC/H2O2 process in degrading chloramphenicol in water

Background: To develop other H2O2-based approaches for the efficient degradation of chloramphenicol, this study elucidates the performance of the nZVC/H2O2 process in the degradation of chloramphenicol in water.Methods: A rotating packed bed (RPB) with blade packings was adopted in the mass-production of nanoscale zero-valent copper (RPB-nZVC). The effects of pH, initial chloramphenicol concentration, nZVC dosage, and H2O2 concentration on the degradation of chloramphenicol using the nZVC/H2O2 process with RPB-nZVC were studied.Significant findings: The results reveal that the optimal nZVC dosage and H2O2 concentration were 250 mg/L and 1.25 mmol/L, respectively. At pH 3 with an initial chloramphenicol concentration of 10 mg/L, an nZVC dosage of 250 mg/L, an H2O2 concentration of 1.25 mmol/L, and a degradation time of 30 min, the nZVC/H2O2 process with the RPB-nZVC degraded 93% of the chloramphenicol. However, at the same operating parameters, the efficiency of degradation of chloramphenicol of 63% was achieved in the nZVC/H2O2 process with commercial nZVC that was obtained from Sigma-Aldrich. Therefore, the nZVC/H2O2 process with RPB-nZVC can be used to degrade strongly chloramphenicol in water.

Degradation of tetracycline using nanoparticles of zero-valent iron and copper

Abstract Tetracycline (TC) is one of the most persistent pharmaceuticals in the ecosystem. Advanced oxidation processes (AOPs) are suitable and effective technology for treating wastewater contaminated with antibiotics such as TC. In this manner, Fenton-like reaction is effective for wastewater treatment from toxicity and non-biodegradable organic pollutants using bimetallic nanoparticles. This study aims to verify the effect of AOPs using ZVI/Cu bimetallic nanoparticles on removing the TC antibiotic via a Fenton-like reaction, and what is necessary to evaluate the factors that influence the reaction, i.e. pH, ZVI/Cu dose, stirring intensity, H2O2 concentration, and initial TC dosage. The obtained results indicated that the TC removal reached up to 82.3% with an initial TC dose of 8 μg/L. In addition, the TC degradation process is more effective in an acidic medium than in an alkaline medium. Furthermore, the TC removal reached up to 85.1% with a ZVI/Cu dose of 1.2 g/L. On the other hand, the optimum mixing intensity value was 200 rpm, and the optimum H2O2 dose was 2 g/L according to the conditions of the present study.

MOF-derived Cu0/C activation of molecular oxygen for efficient degradation of sulfamethazine

Zero-valent copper (ZVC) has shown potential as an oxygen activator for the degradation of organic pollutants from aqueous solution. Nevertheless, the high leaching of copper ions and the demand for acidic condition limited its application. In this study, a novel mesoporous carbon hybrid loaded zero-valent copper (Cu0/C) was successfully synthesized from Cu-based metal–organic framework (Cu3(BTC)2) through a pyrolysis method and applied to efficiently degrade sulfamethazine (SMT) at neutral pH under aeration condition. The performance of Cu0/C composite for the activation of molecular oxygen was evaluated based on the effect of different reaction parameters, such as, initial SMT concentration, initial pH, activator dosage and reaction temperature. The results showed a high efficiency for SMT removal over a broad pH range (3.0–7.0). Moreover, the Cu0/C composite exhibited excellent stability and reusability for SMT degradation, and a 96.7% SMT removal and a 68.8% total organic carbon (TOC) conversion were achieved at pH 5.8 after continuous three cycles. Combined with the determination results of reactive oxidizing species and physical-chemical characterization, cupryl species (Cu3+) rather than OH produced by the reaction of the in-situ generated H2O2 with Cu+ were the major reactive species. Additionally, the possible reaction mechanism of Cu0/C activated oxygen was tentatively proposed.

Effect of copper dispersion on SBA-15 and SBA-16 affinity towards carbon dioxide—an approach through thermal programmed desorption

A new approach for the synthesis of zero-valent copper nanoparticles (CuNPs) supported on ordered mesoporous silica SBA-15 and SBA-16 by using vegetal antioxidants, coffee Robusta and green tea was developed in the present work. Diverse characterization techniques such as X-ray diffraction, nitrogen adsorption–desorption, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and thermal programmed desorption of CO2 and water allowed stating that the appreciable specific surface area and porosity favor CuNP formation. Copper-loaded SBA-15 and SBA-16 exhibited higher surface basicity and hydrophilic character according to the type of the source of reducing agents and silica framework, respectively. OH-compounds interactions with both CuNP and SBA surface and more particularly with available Si–O-Si groups were found to promote metal dispersion reducing the particle size. The results obtained herein open promising prospects for designing low cost and “green” silica-based materials with judiciously tailored basicity and hydrophilic character for catalysis, adsorption and other surface processes.

Removal of diclofenac in water using peracetic acid activated by zero valent copper

In this work, the degradation kinetics and mechanism of diclofenac (DCF) using peracetic acid (PAA) activated by zero valent copper (ZVC) were systematically investigated. It was found that PAA could be catalyzed effectively by ZVC to produce HO•, CH3COO• and CH3COOO•, which were responsible for the removal of DCF. Based on the XPS, XRD and FESEM characterization results of ZVC before and after reaction, the corrosion of ZVC was occurred to produce Cu+ under acidic condition, which was the main activator for PAA, H2O2 and O2. The recommended pH for this reaction system was 3.0, and DCF degradation was enhanced gradually with increasing ZVC dose and PAA dose. The existence of Cl-, CO32–, Fe3+, Cu2+ and dissolved organic matter (DOM) promoted DCF degradation in ZVC/PAA system, while SO42- and NO3– had almost no influence on DCF removal. Six intermediates were identified in this system, and the probable degradation mechanism of DCF was thus proposed, including seven transformation pathways, i.e., hydroxylation, amidation, dechlorination-cyclizaiton, dechlorination-hydrogenation, dechlorination-hydroxylation, decarboxylation and formylation. This study provides a new method for PAA activation and DCF removal from the polluted water.

Optimization of catalytic wet oxidating fulvic acid with zero-valent copper chitosan activated carbon ball as the catalyst

The degradation efficiency of fulvic acid (FA) was investigated in the catalytic wet oxidation process (CWPO) by zero-valent copper chitosan activated carbon ball (ZVC/CTS-ACB). Characterization of ZVC/CTS-ACB shows that zero-valent copper was loaded successfully on the chitosan activated carbon. Plackett–Buiman (PB) design and response surface methodology (RSM) were employed to determine the influence factors and the optimum processing parameters. The model was well fitted to the actual data and the correlation coefficients of R2 and R2-adj were 0.9359 and 0.9039, respectively. Under the obtained optimum conditions for FA degradation: temperature = 94 °C and pH 3.8, the average FA removal by three replicate experiments was 93.02%, which has a high consistency to the RSM optimal target response of 93.86%. The comparison of catalytic performance showed that the addition of catalyst ZVC/CTS-ACS could increase the removal rate of FA, color number (CN) and TOC by 93.6%, 83.5% and 81.9% respectively. The high TOC removal rate indicated the good performance of the catalyst to FA mineralization. Additionally, the ICP analysis of copper ion leaching was only 0.08 mg/l after 5 repeated recycles of the catalyst, demonstrating the high stability of ZVC/CTS-ACB that is beneficial for the actual application.

Catalytic Effect of Copper on Ozonation in Aqueous Solution

ABSTRACT Catalytic effects of cupric ion (Cu2+) and zero-valent copper (Cu0) on ozonation in aqueous solution were discussed in this research using 1,4-dioxane as a radical probe. Ozonation with Cu0 enhanced 1,4-dioxane removal, whereas Cu2+ had no catalytic effect. Two initiation steps were proposed for the catalytic effect of Cu0; the corrosion of Cu0 by oxygen and ozone and a one-electron redox reaction of Cu0 with ozone. The former produced cuprous ion (Cu+) and the latter produced both Cu+ and ozonide ion (O3˙−). Hydroxyl radicals (HO˙) was generated by the reaction of Cu+ with ozone and protonation of O3˙−.

Novel nanocomposite of biochar-zerovalent copper for lead adsorption.

In this study, a composite of zerovalent copper-biochar was investigated for its ability to remove lead from water. The prepared material was characterized by using scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), X-ray diffractomter (XRD), and X-ray photoelectron spectroscopy (XPS). The pH effect on adsorption of lead was investigated within the range of 2-8 and the effect of temperature was studied at 303, 308, 313, and 318 K. The kinetics of lead adsorption on biochar composite was evaluated and the equilibrium time of 12 hr was established. To further evaluate the nature of adsorption, Langmuir model was tested and the adsorption capacities were evaluated for lead adsorption on the surface of copper biochar composite. The activation energy, entropy, and enthalpy values indicated the adsorption phenomenon to be chemisorptive and spontaneous in nature. Comparison of adsorption capacities with the reported adsorbents in the literature concluded zerovalent copper-biochar composite to be an efficient adsorbent for the removal of lead in the experimental conditions under study. RESEARCH HIGHLIGHTS: Highly efficient composite of zerovalent copper with biochar was synthesized for lead adsorption. XPS and XRD shows the presence of zerovalent copper in the biochar composite. pH and temperature were the main governing factors in the adsorption process. Adsorption capacity for lead is higher than many of the reported adsorbents.

Catalytic Effect of Copper on Ozonation in Aqueous Solution

ABSTRACT Catalytic effects of cupric ion (Cu2+) and zero-valent copper (Cu0) on ozonation in aqueous solution were discussed in this research using 1,4-dioxane as a radical probe. Ozonation with Cu0 enhanced 1,4-dioxane removal, whereas Cu2+ had no catalytic effect. Two initiation steps were proposed for the catalytic effect of Cu0; the corrosion of Cu0 by oxygen and ozone and a one-electron redox reaction of Cu0 with ozone. The former produced cuprous ion (Cu+) and the latter produced both Cu+ and ozonide ion (O3˙−). Hydroxyl radicals (HO˙) was generated by the reaction of Cu+ with ozone and protonation of O3˙−.

Cu-Zn bimetal ZIFs derived nanowhisker zero-valent copper decorated ZnO nanocomposites induced oxygen activation for high-efficiency iodide elimination

Studies on the elimination of iodide anions (I−) by Cu-based adsorbents have been conducted for decades, however its unsatisfactory adsorption performance and its non-reusability are still the main obstacles for large-scale practical applications. Here, an efficient technique was proposed for the elimination of iodide using nanowhisker zero-valent copper (nwZVC) decorated ZnO nanocomposites obtained by two steps pyrolysis of Cu-Zn bimetal ZIFs precursors. The as-synthesized materials were extensively characterized and the results clearly revealed that nanoscale ZVC were well-dispersed in the ZnO matrix, and the morphology and the amount of nanoscale ZVC could be tuned by adjusting the molar ratio of Cu/Zn in ZIF precursors. The following batch adsorption experiments demonstrated that the resultant materials exhibited high adsorption capacity of 270.8 mg g−1 under condition of adequate oxygen, as well as high selectivity, strong acidity resistance and an excellent reusability. The mechanism investigations revealed that the elimination of I− by as-fabricated materials involved adsorption process coupled with oxidation, and the existence of nwZVC was responsible for this since nwZVC could activate molecular oxygen to generate H2O2 accompanied by the release of Cu+, thus leading to I− adsorbed by the released Cu+ and oxidized by the H2O2.

Copper mining bacteria: Converting toxic copper ions into a stable single-atom copper.

The chemical synthesis of monoatomic metallic copper is unfavorable and requires inert or reductive conditions and the use of toxic reagents. Here, we report the environmental extraction and conversion of CuSO4 ions into single-atom zero-valent copper (Cu0) by a copper-resistant bacterium isolated from a copper mine in Brazil. Furthermore, the biosynthetic mechanism of Cu0 production is proposed via proteomics analysis. This microbial conversion is carried out naturally under aerobic conditions eliminating toxic solvents. One of the most advanced commercially available transmission electron microscopy systems on the market (NeoArm) was used to demonstrate the abundant intracellular synthesis of single-atom zero-valent copper by this bacterium. This finding shows that microbes in acid mine drainages can naturally extract metal ions, such as copper, and transform them into a valuable commodity.

Simple borophosphate glasses for on-demand growth of self-supported copper nanoparticles in the reduction of 4-nitrophenol

Herein, we demonstrate a single-step synthesis of simple copper-doped borophosphate glasses and their unusual use for catalytic reduction of nitro groups from the aromatic nitro compounds. The copper-doped glasses were evaluated as an affordable heterogeneous catalytic glass-based material for the reduction of 4-nitrophenol by sodium borohydride. The glass matrix acts as a host and support material for in situ self-growth of zero-valent copper (Cu) nanoparticles (NPs) on the glass surface. Thus, zero-valent CuNPs are produced in situ on the glass surface that is accomplished by the interaction of copper ions with hydride ions. Using an intrinsic reaction kinetic constant, we find a catalytic activity of 0.144 L s−1 g−1 for a glass-based catalyst doped with a non-noble metal, which is an order of magnitude higher when compared to the values observed elsewhere. Furthermore, the reuse of glass catalyst after six successive cycles demonstrates an outstanding performance compared to that of the parent material. A mathematical model based on the Langmuir-Hinshelwood mechanism related to an empirical growth rate of the zero-valent CuNPs was proposed to describe the kinetic of the 4-nitrophenol catalytic hydrogenation.