Adsorption of carbonyl sulfide on modified activated carbon under low-oxygen content conditions

Activated carbon sorbents impregnated with KOH, Fe(NO₃)₃, Cu(NO₃)₂, Zn(NO₃)₂ or Co(NO₃)₂ and their applications in catalytic oxidation reaction of COS were investigated. The results showed that the activated carbon modified with 10 % (mass percentage) KOH enhanced the adsorption ability significantly. And it was also found that the oxygen content and temperature were the two most important factors in the COS adsorption. Further investigation on the pore structures of the samples with X-ray photoelectron spectroscopy indicated that an adsorption/oxidation process happened in the KOH modified activated carbon in which the major existing forms of sulfur were SO₄ ^2? and S species. The oxidation of COS suggested that KOH in the micropores may play a catalytic role during the adsorption. On the other hand, we found that the desorption activation energy from KOHW was higher than that from AC by the CO₂-TPD spectra, which indicated the adsorption of CO₂ on KOH impregnated activated carbon was stronger. The strong adsorption could be attributed to the basic groups on the activated carbon surface. In conclusion, the activated carbon impregnated with KOH promises a good candidate for COS adsorbent.     

Simultaneous removal of NO<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript> and SO<Subscript>2</Subscript> by low-temperature selective catalytic reduction over modified activated carbon catalysts

A series of modified porous activated carbon (AC) catalysts prepared by impregnation were investigated for the low-temperature (≤250°C) selective catalytic reduction (SCR) of NO _x with NH₃ with simultaneous removal of SO₂. The effects of various preparation conditions and reaction conditions on NO and SO₂ conversions were observed, such as support type, active components, copper loading, calcination temperature and presence of H₂O and O₂. The modified AC catalysts were characterized by BET, XRD, TG and TPX methods. The activity test results showed that the optimal catalyst is 15% Cu/WCSAC which can provide 52% NO conversion and 68% SO₂ conversion simultaneously at 175°C with a space velocity of 30000 h^?1, and the optimal calcination temperature was 500°C. The presence of H₂O could inhibit NO conversion and promote the SO₂ conversion. The effect of O₂ (0–5%) was evaluated, and the NO and SO₂ conversions were best when the concentration of O₂ was 3%. Research demonstrated that Cu/WCSAC catalyst was a kind of potential catalysts due to the amorphous phase, high specific areas and high active ability.     

Thermoanalytical investigation of the decomposition course of copper oxysalts

The thermal decomposition of copper nitrate trihydrate (CuNTH); Cu(NO₃)₂·3H₂O was studied up to 600°C by thermogravimetry (TG) and differential thermal analysis (DTA) in a dynamic atmosphere of air. The thermal events occurring throughout the decomposition course were characterized on the basis of spectral analyses using infrared spectroscopy (IR), X-ray diffractometry (XRD) and scanning electron microscopy (SEM). Non-isothermal kinetic parameters were determined. The results showed that the decomposition course involves two main processes, firstly the formation of hydroxy copper nitrate and secondly, the decomposition of this compound to yield CuO. Pathways were suggested that may be involved in the decomposition course.     

The effect of heating temperature and nitric acid treatments on the performance of Cu- and Zn-based broad spectrum respirator carbons

Impregnated activated carbons (IACs) that are used in broad spectrum gas mask applications have historically contained copper and/or zinc impregnants. The addition of an oxidizing agent, such as nitric acid (HNO(3)) can be useful in distributing the metallic impregnants uniformly on the activated carbon substrate. In this work, we study IACs prepared from copper nitrate (Cu(NO(3))(2)) and zinc nitrate (Zn(NO(3))(2)) precursors as a function of HNO(3) content present in the impregnating solution and as a function of heating temperature. The gas adsorption capacity of the IACs was determined by dynamic flow testing using sulfur dioxide (SO(2)), ammonia (NH(3)), hydrogen cyanide (HCN) and cyclohexane (C(6)H(12)) challenge gases under dry and humid conditions. The thermal decomposition and distribution of the impregnant on the activated carbon substrate is studied using X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermal analysis techniques. Relationships between gas adsorption capacity, impregnant distribution and the species of surface impregnants are discussed.     

Copper(II) oxalate obtained through the reaction of 1,2-ethanediol with Cu(NO<Subscript>3</Subscript>)<Subscript>2</Subscript>·3H<Subscript>2</Subscript>O

The paper presents the experimental results of the structural investigations and thermal analysis of copper(II) oxalate, a polynuclear coordination compound, obtained by a new method, through the reaction of 1,2-ethanediol with Cu(NO₃)₂·3H₂O. The reaction between 1,2-ethanediol and Cu(NO₃)₂·3H₂O occurs, under some working conditions, with the oxidation of 1,2-ethanediol to the oxalate anion (L). The synthesized polynuclear coordination compound, [CuL·0.3H₂O]_n, was characterized by chemical analysis, electronic and vibrational spectra and thermal analysis. The thermal properties of the polynuclear coordination compound have been investigated by TG, DTG and DSC. The obtained decomposition product is CuO. Powder XRD (X-ray diffraction), IR spectroscopy and TEM (transmission electron microscopy) were used to characterize the composition, the crystalline structure and the surface morphology of the copper oxide obtained through thermolysis. The thermal conversion product, copper(II) oxide, has a microporous structure with a large specific area.     

Potentiometric,spectral characterization,and antioxidant activity studies of ternary complexes involving Cu(II) and carbamoylcholine chloride drug with amino acids

A potentiometric method was used to determine the stability constants for the various complexes of copper(II) with carbamoylcholine chloride (C) drug as a ligand in the presence of some biorelevant amino acid constituents like glycine (Gly), alanine (Ala), valine (Val), proline (Pro), β-phenylalanine (Phe), S-methylcysteine (Met), threonine (Thr), ornithine (Orn), lysine (Lys), histidine (Hisd), histamine (Hist), and imidazole (Imz) as ligands (L). Stability constants of complexes were determined at 25°C and I = 0.10 mol/L NaNO₃. The relative stability of each ternary complex was compared with that of the corresponding binary complexes in terms of Δlog K and % R.S. values. Cu(II) complexes of drug C were synthesized in 1:1 and 1:1:1 M ratios of copper to drug [Cu(C)(NO₃)₂] (1) and copper to drug to glycine[Cu(C)(Gly)(NO₃)].NO₃ (2), respectively. Glycine ternary complex with drug and copper [Cu(C)(Gly)(NO₃)].NO₃ was considered as representative amino acid. The complexes 1 and 2 were isolated and characterized using various physicochemical and spectral techniques. Both complexes 1 and 2 were found to have magnetic moments corresponding to one unpaired electron. The possible square planar and square-pyramidal geometries of the copper (II) complexes were assigned on the basis of electron paramagnetic resonance (EPR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), X-ray powder diffraction (XRPD), ultraviolet–visible (UV–Vis) and infrared (IR) spectral studies, and the discrete Fourier transform method from DMOL3 calculations. Antioxidant activities of all the synthesized compounds were also investigated.     

Synthesis and Structure of Copper(II) Nitrate Complexes with 2, 6‐Bis(pyrazolyl)pyridine

Three mononuclear copper(II) complexes of copper nitrate with 2, 6‐bis(pyrazol‐1‐yl)pyridine ( bPzPy ) and 2, 6‐bis(3′,5′‐dimethylpyrazol‐1‐yl)pyridine ( bdmPzPy ), [Cu(bPzPy)(NO₃)₂] ( 1 ), [Cu(bPzPy)(H₂O)(NO₃)₂] ( 2 ) and [Cu(bdmPzPy)(NO₃)₂] ( 3 ) were synthesized by the reaction of copper nitrate with the ligand in ethanol solution. The complexes have been characterized through analytical, spectroscopic and EPR measurements. Single crystal X‐ray structure analysis of complexes 1 and 2 revealed a five‐coordinate copper atom in 1 , whereas 2 contains a six‐coordinate (4+2) Cu^II ion with molecular units acting as supramolecular nodes. These neutral nodes are connected through O–H ··· O(nitrate) hydrogen bonds to give couples of parallel linear strips assembled in 1D‐chains in a zipper‐like motif.     

Studies on the thermal decomposition of Cu(NO3)2 · 3 H2O

The thermal decomposition of Cu(NO₃)₂ · 3 H₂o was studied using DTA, DTG, TG and X-ray techniques. The three endothermic changes were analyzed and the intermediate compound formed was confirmed as monoclinic basic copper nitrate, Cu(NO₃)₂· · 3 Cu(OH)₂. With a hot-plate microscope the melting point of Cu(NO₃)₂ · 2 H₂O was determined as 391 K.     

The effect of transition metals on the structure of h-BN intercalation compounds

In this study, hexagonal boron nitride (h-BN) were synthesized by the modified O’Connor method in the presence of various metal nitrates [M(NO₃)_x, M=Cr, Mn, Fe, Co, Ni, Cu, Zn, and Ag]. The composites were analyzed by FTIR, XRF, XRD, and SEM techniques. XRD results indicated a change in the interlayer spacing due to the intercalation of Cr, Mn, Fe and Ag. SEM analyses illustrated the grain growth upon metal intercalation even at a temperature of 1320 K.     

Synthesis and structure of copper(II) coordination compounds with 8-quinolinecarboxaldehyde thio- and 4-phenylthiosemicarbazones

8-Quinolinecarboxaldehyde thiosemicarbazone (HL) and copper form compounds with a metal: ligand ratio of 1: 1 in which the ligand is either the neutral molecule or the monohydric acid anion. Its acidic properties are enhanced not only as a result of coordination but also due to the electronic effect of substituents in the thiosemicarbazide moiety. 8-Quinolinecarboxaldehyde 4-phenylthiosemicarbazone (HL¹) is coordinated only as the anion. The structures of [Cu(HL)SO₄]₂, [Cu(L)NO₃]₂, and [Cu(L¹)NO₃]₂ · 0.25H₂O, and free HL¹ were studied. The tendency of the complexes to dimerization and association with acid anions or sulfur atoms of the organic ligands as bridges was established. In binuclear compounds with closely spaced magnetic centers, no exchange interaction between them was found. The copper coordination compounds with HL are able to suppress the growth of cancer cells 41M and SK-BR-3 and are promising objects for investigation as anticancer drugs.     

Atmospheric corrosion of copper and silver influenced by particulate matter

The atmospheric corrosion of copper and silver influenced by graphite and alumina as particulate matter (PM) in an environment containing 200 μg m^?3 SO₂ + 150 μg m^?3 NO₂ at 85% RH and 25 °C was analyzed. Different proportions of PM mixture conditions were used, and the corrosion rate was followed using gravimetric analysis. Results of linear sweep voltammetry (LSV) and coulometric reduction (CR) indicated that larger corrosion rates were obtained in the presence of deposited PM. Under present exposure conditions, copper corrosion rate was larger than silver corrosion rate. X-ray diffraction (XRD) shows the presence of cuprite (Cu₂O) and brochantite (Cu₄SO₄(OH)₆) in the case of copper and achantite (Ag₂S) in the case of silver.     

Synthesis and characterization of polycrystalline ZnO/HZSM-5 nanocomposites

Polycrystalline ZnO/HZSM-5 nanocomposites were synthesized by the impregnation method using a home prepared HZSM-5 zeolite as porous support and Zn(C₅H₇O₂)₂ or Zn(NO₃)₂ as zinc precursors. As-prepared samples were characterized by ICP, XRD, SEM (EDS), TEM (SAED), BET and DRS techniques. A small amount of sub-nanometeric ZnO clusters were introduced into the channels of HZSM-5 zeolite. These ZnO clusters exhibited absorption band onset at about 280 nm, different from ZnO particles at about 370 nm. The significant blue shift possesses high quantum size effect in sub-nanometeric ZnO clusters. SAED and TEM images revealed that the ZnO nanoparticles, supported on the surface of HZSM-5 zeolite, were identified as polycrystalline structure with the particle size of about 20-25 nm. XRD results provided evidence of the strong host-guest interactions between HZSM-5 framework and ZnO structure. The samples prepared by Zn(C₅H₇O₂)₂ were more porous and smaller than those prepared from the Zn(NO₃)₂. This was confirmed by SEM and XRD results.     

Adsorption of carbon disulfide on activated carbon modified by Cu and cobalt sulfonated phthalocyanine

A series of adsorbents were studied for removal efficiency of carbon disulfide (CS₂) under micro-oxygen conditions. It was found that activated carbon modified by Cu and cobalt sulfonated phthalocyanine (CoSPc) denoted as ACCu–CoSPc showed significantly enhanced adsorption ability. Reaction temperature was found to be a key factor for adsorption, and 20 °C seems to be optimal for CS₂ removal. Samples were analyzed by N₂-BET, XRD, XPS, SEM–EDS and CO₂-TPD. The characterization results demonstrated that large quantities of SO₄ ^2? anions were formed and adsorbed in the reaction process. SO₂, CS₂ and COS were detected in the effluent gas generated from the temperature programmed desorption of ACCu–CoSPc–CS₂. Therefore, it can be concluded that ACCu–CoSPc most likely acted as a catalyst in the adsorption/oxidation process on the surface of the impregnated sample. The generated sulfide and sulfur oxide can cover the active sites of adsorbents, resulting in pronounced reduction of adsorbent activity. Finally, the exhausted ACCu–CoSPc can be regenerated by thermal desorption.     

Electrodeposition of nanocrystalline aluminium, copper, and copper–aluminium alloys from 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ionic liquid

In this paper, we show that nanocrystalline aluminium, copper, and copper–aluminium alloys can be electrodeposited from the ionic liquid 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate, [Py_1,4]TfO. Furthermore, Al deposition was studied in 1-ethyl-3-methylimidazolium trifluoromethylsulfonate, [EMIm]TfO for comparison. The two employed ionic liquids exhibit different concentration-dependent phase behaviour with AlCl₃. This study comprises cyclic voltammetry, potentiostatic electrolysis, scanning electron microscopy, X-ray diffraction, atomic absorption spectroscopy, and inductively coupled plasma optical emission spectroscopy. Thick (in micrometre regime) and uniform layers of aluminium deposits were obtained from 2.75?M AlCl₃ in [Py_1,4]TfO at 100?°C. The average crystallite size of aluminium was found to be around 40 to 50?nm. However, a coarse and cubic-shaped Al deposit with crystal sizes in the micrometre regime was obtained from [EMIm]TfO. Electrodeposition of copper was investigated in [Py_1,4]TfO-containing Cu(TfO)₂ at 100?°C. The average grain size of the copper deposit obtained from the electrolysis is around 20 to 40?nm. Electrodeposition of copper–aluminium alloys was successful in the same ionic liquid at 100?°C. Thick layers of copper–aluminium alloys were obtained from the employed ionic liquid. XRD analysis of the obtained deposits from electrolysis experiments revealed that Cu₃Al alloy was formed. SEM analysis indicated that the nanocrystalline copper–aluminium deposits have an average grain size of 60 to 70?nm.     

Thermal decomposition of Cu(II) complexes with salicylaldehyde S-methyl thiosemicarbazone

The thermal decomposition of copper(II) complexes with salicylaldehyde S-methylthiosemicarbazone of general formula Cu(HL)X·nH₂O (X=Py+NO₃, NCS, 0.5SO₄) and [Cu(L)NH₃]·H₂O was investigated in air atmosphere in the interval from room temperature to 1000°C. Decomposition of the complexes occurred in several successive endothermic and exothermic processes, and the residue was in all cases CuO.     

A Comparison of NO Reduction Over Mn–Cu/ZSM5 and Mn–Cu/MWCNTs Catalysts Assisted by Plasma at Ambient Temperature

Manganese–copper bimetal oxide catalysts supported on ZSM5 and acid-treated multi-walled carbon nanotubes (MWCNTs) were produced by incipient wetness impregnation for selective catalytic reduction of NO with dielectric barrier discharge plasma. Plasma can activate molecules even at ambient temperature, generating active oxygen species such as O, O₃, and HO₂ radicals, which can oxidize NO to NO₂ effectively. The SCR activity of Mn–Cu/MWCNTs was studied and compared to that of the Mn–Cu/ZSM5. The obtained samples were characterized by XRD, SEM, TEM, ICP, H₂-TPR, Raman spectroscopy, and XPS. The results show that Mn–Cu/MWCNTs catalyst possesses NO removal activity superior to that of the Mn–Cu/ZSM5 catalyst. MWCNTs-based catalyst attains NO removal efficiency of 88% at 480 J/L, while the ZSM5-supported catalyst achieves NO removal efficiency of 82% at the same energy density. The oxygen content increased from 3.33 to 19.07% on the nanotube surface after introducing Mn and Cu, which almost remained unchanged on ZSM5. The oxygen-containing functionalities are important for NO_x adsorption and removal. Moreover, the characterization revealed that CuO is the main phase of copper oxide, but copper dispersion decreases on Mn–Cu/ZSM5 surface because of the formation of copper dimer species. The manganese is well-dispersed on the catalysts, MnO₂ and Mn₂O₃ contents of Mn–Cu/MWCNTs are larger than that of Mn–Cu/ZSM5, MnO₂ is the predominant phase of manganese oxide.     

Physico-chemical characterization of thermal decomposition course in zinc nitrate-copper nitrate hexahydrates

This study reports experimental investigations by non-isothermal TG/DSC analysis of Zn(NO₃)₂·4H₂O, Cu(NO₃)₂·4H₂O and their mixtures of known compositions in the temperature range 30–1200°C. Solid/liquid transitions in the sealed samples of the hexahydrate salts and their mixtures were also studied by DSC in the temperature range 0–60°C. The mixture with composition 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O showed single melting peak at 29°C. This mixture was chosen for detailed studies. Melting temperature and heat of fusion of single salt hexahydrates and of the mixture were calculated from DSC endotherms. The different stages in the thermal decomposition processes have been established. The intermediate and the final solid products of the thermal decomposition were analyzed by XRD. The scheme and the decomposition temperature depended on the composition of the starting material. The final decomposition products were CuO (monoclinic), Cu₂O (cubic), ZnO (hexagonal) and their mixtures with the defined crystalline structures. Possible influence of the addition of CuCl₂·2H₂O into the mixture 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O and a gel combustion technique of the precursor preparation, on the composition and morphology of the solid decomposition products, were also studied. The gel combustion technique, using citric acid added to a mixture of 0.85Zn(NO₃)₂·6H₂O+0.15Cu(NO₃)₂·6H₂O, was applied in an attempt to obtain mixed Zn/Cu oxides of a particular mole ratio. The morphology of the solid decomposition products was examined by SEM.     

Evolved gas analyses on a mixed valence copper(I,II) complex salt with thiosulfate and ammonia by in situ TG-EGA-FTIR and TG/DTA-EGA-MS

Thermal decomposition of a mixed valence copper salt, Na₄[Cu(NH₃)₄][Cu(S₂O₃)₂]₂·0.5NH₃ (1) prepared from pentahydrates of sodium thiosulfate and copper sulphate of various molar ratios in 1:1 v/v aqueous ammonia solution, has been studied up to 1,000 °C in flowing air by simultaneous thermogravimetric and differential thermal analysis coupled online with quadrupole mass spectrometer (TG/DTA-MS) and FTIR spectrometric gas cell (TG-FTIR), in comparison. Compound 1 releases first but very slowly some of the included ammonia till 170 °C, then simultaneously ammonia (NH₃) and sulphur dioxide (SO₂) from 175 to 225 °C, whilst the evolution of SO₂ from thiosulfate ligands continues in several overlapping stages until 410 °C, and is escorted by explicit exothermic heat effects at around 237, 260, 358 and 410 °C. The former two exothermic DTA-peaks correspond to the simultaneous degradation and air oxidation processes of excess thiosulfate anions not reacted by formation of copper sulfides (both digenite, Cu_1.8S and covellite, CuS, checked by XRD) and sodium sulfate, while the last two exothermic peaks are accompanied also by considerable mass gains, as the result of two-step oxidation of copper sulfides into various oxosulfates. The mass increase continues further on until 580 °C, when the sample mass begins to decrease slowly, as a continuous decomposition of the intermediate copper oxosulfates, indicated also by re-evolution of SO₂. At 1,000 °C, a residual mass value of 64.3% represents a stoichiometric formation of Cu^IIO and anhydrous Na₂SO₄.     

Stereochemical versatility of Cu(II): Cu(II) complexes of benzyl methyl ketone semicarbazone

Copper(II) complexes of the general composition Cu(ligand)₂X₂ (where X = Cl, Br, NO₃, ClO₄, and $\text{1}\text{2}$SO₄) and Cu(ligand)(CH₃COO)₂ have been synthesised with benzymethylketonesemicarbazone. All the complexes prepared have been characterised by elemental analysis, magnetic moment, conductance, IR, electronic and electron spin resonance spectral studies. The complexes Cu(ligand)₂X₂ (X = Cl, Br, NO₃) and Cu(ligand)(CH₃COO)₂ may have tetragonal symmetry while the Cu(ligand)₂X₂ (ClO₄ and $\text{1}\text{2}$SO₄) may be five-coordinate trigonal bipyramidal in structure.     

A novel one-dimensional copper(II) imino nitroxide polymer

A copper(II) complex [Cu(im2-py)(4,4′-bipy)(NO₃)](NO₃)·1.5H₂O (im2-py?=?2-(2′-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl; 4,4′-bipy?=?4,4′-bipyridyl) has been synthesized by reaction of Cu(NO₃)·3H₂O with im2py and 4,4-bipyridyl in methanol solution. Its crystal structure has been determined by X-ray diffraction. The structure shows that each copper ion is coordinated by a bidentate imino nitroxide radical, two 4,4′-bipyridyl ligands and a nitrate group to form a distorted square pyramidal environment. The crystal structure consists of chains of copper ions linked by 4,4′-bipyridyl.