Proportion Of Cu Research Articles

Improved geochemical baseline establishment based on diffuse sources contribution of potential toxic elements in agricultural alluvial soils

Intense input of potential toxic elements (PTEs) from diffuse anthropogenic sources to agricultural alluvial soils has caused bias in the geochemical baseline value (GBV) established by current methods. This study intends to assess the extent of bias and establish the GBV for 9 PTEs based on their source contribution on the largest alluvial islands in China, the Chongming Islands. The results of total PTE concentrations in soil samples (n = 120) showed that the islands were influenced by PTEs from various diffuse sources. Source identification methods provided a common conclusion that Ni, Co and Cr were dominated by the Yangtze River sediment input and thus more enriched in “recent” alluvial soils which were generated by large-scale reclamation practices. Positive matrix factorization quantified that pesticides and mineral fertilizer contributed 84.3% of As and 63.6% of Cd, especially in “old” soils, while a large proportion of Cu, Sb, Pb and Zn came from atmospheric deposition. Accumulation of PTEs was enhanced by soil sorption phases including organic matter and clay. Because of this differentiation in source contribution, the GBV of As, Cd, Co and Ni established on “recent” soils are significantly different from those established on data from the whole area. Using this source-based GBVs, the geoaccumulation index method suggested that 37% and 25% of the sampling sites were contaminated by As and Cd, respectively. This study emphasized the importance of considering different sources contribution in GBV determination to avoid underestimation of enrichment of PTEs from intense human diffuse sources.

Preparation of Antibiotic-Loaded Copper-Doped Hydroxyapatite Microspheres and Evaluation of Their Antibacterial and Osteogenic Effect

To explore the preparation method of copper (Cu)-doped hydroxyapatite (HA) microspheres loaded with vancomycin (Van), and evaluate their antibacterial and osteogenic effects in vitro. The Cu doped HA microspheres (Cu-HA) with molar doping ratios of 1%, 5%, 10%, and 20% were prepared by hydrothermal synthesis. The microscopic morphology changes were observe with scanning electron microscope. X-ray diffractometer (XRD) was used to study the phase composition and analyze the crystallinity of the sample. Cu-HA with a molar doping ratio of 10% was selected for analysis of the elemental composition of the sample with energy dispersive X-ray spectroscopy (EDS), and was then coated with polydopamine (PDA) as the medium to prepare Cu-HA-PDA. XRD and Fourier infrared spectrometer were used to examine the coating effect of the sample. Van was load on Cu-HA-PDA to prepare Cu-HA-PDA-Van. HA, Cu-HA, HA-PDA, and Cu-HA-PDA-Van were added to α medium at 10 mg/mL to prepare different groups of extract solutions.The main components of the extract solutions were examined, and the Van concentration was checked. We examined the toxic effect of material extract solutions on osteogenic precursor cells and the proliferation and differentiation of bone marrow mesenchymal stem cells, and checked the expression of osteocalcin ( OCN), runt-related transcription factor 2 ( RUNX-2), and alkaline phosphatase ( ALP), the osteogenic related genes. Sterilized HA, Cu-HA, HA-PDA, Cu-HA-PDA, Cu-HA-DPA-Van microsphere materials were prepared, and the colony counting method was used to evaluate the antibacterial effect of the materials for Staphylococcus aureus. Various types of Cu-doped HA (Cu-HA) were successfully synthesized. As the proportion of Cu increased, the morphology gradually changed from being strip or belt-shaped to a uniform spherical shape. Cu-HA of 10% molar doping ratio showed a clearly microspherical shape and a petal-like porous micro-nano morphology on the surface. EDS and XRD analyses showed that the main structure of the material was still made up of hydroxyapatite crystals and Cu was successfully doped with HA. The infrared spectrometer showed that the PDA was successfully coated on the surface of the material. Examination of the main components of the extract solution once again verified that the Cu element had successfully entered and replaced part of the Ca element in the HA. The 10 mg/mL Cu-HA-PDA-Van extract solution contained 0.27 mg/mL of Van. In vitro cell experiments and bone-formation-related gene testing showed that Cu-HA-Van had good biological activity and promoted bone differentiation. The minimum inhibitory concentration (MIC) of Cu-HA-PDA-Van microspheres was 16 μg/mL. Compared with Cu-HA, HA-PDA and pure HA, Cu-HA-Van microspheres had significant and long-lasting antibacterial effects. Cu element was used to control the microscopic morphology of HA, and the Cu-HA-PDA-Van microspheres prepared by successfully coating of PDA and loading of Van had good antibacterial properties and biological activity.

Uranotungstite, the only natural uranyl tungstate: Crystal structure revealed from 3D electron diffraction

Abstract Uranotungstite is an uranyl-tungstate mineral that was until recently only partially characterized with a formula originally given as (Fe2+,Ba,Pb)(UO2)2(WO4)(OH)4·12H2O and an unknown crystal structure. This mineral has been reinvestigated by electron microprobe analysis coupled with three-dimensional electron diffraction. According to the electron microprobe data, the holotype material from the Menzenschwand uranium deposit (Black Forest, Germany) has the empirical formula (Ba0.35Pb0.27)Σ0.62[(U6+O2)2(W0.986+☐0.75)O4.7(OH)2.5(H2O)1.75](H2O)1.67 (average of 8 points calculated on the basis of 2U apfu; H2O content derived from the structure). According to the precession-assisted 3D ED data, holotype uranotungstite from Menzenschwand is monoclinic, P21/m, with a = 6.318(5) Å, b = 7.388(9) Å, c = 13.71(4) Å, β = 99.04(13)°, and V = 632(2) Å3 (Z = 2). The structure refinement of the 3D ED data using the dynamical approach (Robs = 0.0846 for 3287 independent observed reflections) provided a structure model composed of heteropolyhedral sheets. A β-U3O8-type sheet of idealized composition [(UO2)2W6+Fe0.253+☐0.75O4.75(OH)1.5(H2O)1.75]0.25– is composed of UO7 polyhedra linked by (W,Fe)O5 polyhedra in which the W:Fe ratio is variable as well as the bulk occupancy of this site; the W site may also host a minor proportion of Cu, Mg, or V. In uranotungstite, the interlayer spaces between adjacent U-W-O sheets host water on one side and, on the other side, a partially occupied cation site mostly occupied by Ba and, to a lesser extent, Pb, as well as a partially occupied H2O site. This work is the first structural description of a natural uranyl-tungstate mineral and confirms the great structural and chemical flexibility of β-U3O8 type of sheets.

Construction of Novel Nanocomposites (Cu-MOF/GOD@HA) for Chemodynamic Therapy.

The emerging chemodynamic therapy (CDT) has received an extensive attention in recent years. However, the efficiency of CDT is influenced due to the limitation of H2O2 in tumor. In this study, we designed and synthesized a novel core-shell nanostructure, Cu-metal organic framework (Cu-MOF)/glucose oxidase (GOD)@hyaluronic acid (HA) (Cu-MOF/GOD@HA) for the purpose of improving CDT efficacy by increasing H2O2 concentration and cancer cell targeting. In this design, Cu-MOF act as a CDT agent and GOD carrier. Cu(II) in Cu-MOF are reduced to Cu(I) by GSH to obtain Cu(I)-MOF while GSH is depleted. The depletion of GSH reinforces the concentration of H2O2 in tumor to improve the efficiency of CDT. The resultant Cu(I)-MOF catalyze H2O2 to generate hydroxyl radicals (·OH) for CDT. GOD can catalyze glucose (Glu) to supply H2O2 for CDT enhancement. HA act as a targeting molecule to improve the targeting ability of Cu-MOF/GOD@HA to the tumor cells. In addition, after loading with GOD and coating with HA, the proportion of Cu(I) in Cu-MOF/GOD@HA is increased compared with the proportion of Cu(I) in Cu-MOF. This phenomenon may shorten the reactive time from Cu-MOF to Cu(I)-MOF. The CDT enhancement as a result of GOD and HA effects in Cu-MOF/GOD@HA was evidenced by in vitro cell and in vivo animal studies.

Combination of Cu-Pt-Pd nanoparticles supported on graphene nanoribbons decorating the surface of TiO2 nanotube applied for CO2 photoelectrochemical reduction

The photoelectrocatalysis (PEC) technique was applied in CO2 reduction using different proportions of Cu, Pd, and Pt supported on graphene nanoribbons (GNR) and deposited on the surfaces of TiO2 nanotubes. Altogether, nine combinations of TiO2-NT/GNR-metal were assembled, although only three of them efficiently promoted the generation of methanol and ethanol in high quantities. Comparison with the photocatalysis, photolysis, and electrocatalysis techniques showed the extremely high efficiency of PEC, which enabled production of methanol and ethanol at levels around 19.2-fold and 44.4-fold higher, respectively, than photocatalysis, the second most efficient technique. The presence of metallic nanoparticles in the system facilitated CO2 reduction due to the trapping of the photogenerated electrons, prolonging their lifetime, lowering the reaction energy barrier for CO2 reduction, and provided active intermediates. Therefore, the assembly of these materials containing low amounts of metals is highly promising, since it can assist in alleviating environmental problems caused by CO2 emissions, while at the same time enabling the energetically efficient generation of compounds of commercial value.

A Study on Morpho-Nutritional Variability Among Lablab Bean Genotypes

To evaluate the morphological and nutritional variability among six lablab bean (Lablab purpureusL.) genotypes, a study was carried out at Sylhet Agricultural University, Bangladesh and at Bangladesh Agricultural Research Institute (BARI) during mid-July 2014 to mid-March 2015. Significant morphological variations were noted in both seedling and vegetative stages in their growth. In addition, there were three distinct flower and flower wings color viz. white in SB003; violet in SB010, Rupvan, Auto, and Kanchan; and light violet in SB011 were noted among the genotypes. Further, 8 or 9 layers of flower wings were observed among the genotypes and the inflorescence length varied from 46.40 cm (SB011) to 42.40 cm (SB010). Considering the pod characteristics, pod length and breadth varied from 14.13 cm (SB011) to 8.13 cm(SB010), and 2.68 cm (Auto) to 2.43 cm (SB010), respectively. Significant variations were also noted for pod yield characteristics. The genotype of Kanchan had the highest number of pod/plant (202.7), whereas Auto had the highest pod yield (23.05 t/ha) followed by Kanchan (19.26 t/ha).The study also revealed that pod yield (t/ha) was positively correlated with the number of pods/plant (0.71), pod weight/plant (1.00), individual pod weight (0.65) and pod yield/decimal (1.00) among the genotypes. Furthermore, significant variations were also noted for the nutrient compositions among the genotypes. The analytical experiment shows that Auto had the highest proportion of Cu (15.28 ppm), Fe (122.22 ppm), Mn (40.74 ppm), B (60.60 ppm), S (0.158 %) and Ca (1.67%). In contrast, the genotype of SB003 had the highest amount of Zn (61.86 ppm) and SB011 had Mg (785 %) content. Therefore, the genotypes of Auto and Kanchan would be recommended for cultivation in the Sylhet region of Bangladesh.

Trace element partitioning during coal preparation: Insights from U.S. Illinois Basin coals

A suite of 72 samples of Illinois Basin coal was collected from 2015 to 2018, from 14 active coal mining and preparation operations in Illinois and Indiana. The goals of the study were to investigate the behavior of trace elements during coal preparation and provide current coal quality data for active mining operations in the Illinois Basin, which has become one of the most important suppliers of U.S. coal. Samples include raw coal, cleaned coal, and waste (refuse) coal. The efficiency of cleaning is shown by reduction of ash yield, increase in heating values, and a pronounced shift in the proportion of sulfur forms. In most raw coals, pyritic sulfur (Py S) exceeds organic sulfur (Org S; Org S/Py S ≤ 1.0), whereas in prepared coals, organic sulfur is the predominant sulfur form (Org S/Py S ≥ 1.0). In waste (refuse) coals, Org S/Py S is substantially reduced, or almost entirely in the pyritic form (Org S/Py S near zero). Trends in the distribution of inorganically-associated lithophile and chalcophile elements are shown, as well those for elements having mixed organic-inorganic associations and those that are primarily organic-hosted. Lithophile elements, including Li, Al, P, Ti, Sc, Rb, Y, Zr, Nb, Cs, Ba, the lanthanides, Hf, Th, and U, are partitioned into waste coals with corresponding reduction in cleaned coals. At the same time, chalcophile elements hosted by pyrite, such as As, Sb, Hg, and Pb, are also partitioned into waste coals. Rare earth elements (REEs), including Sc, Y, and the lanthanides, are enriched in waste coals at levels that approximate their content in the upper continental crust (UCC). Several other critical elements, defined as mineral commodities deemed critical to the economy and security of the United States, including V, Cr, As, Rb, Sb, and Cs, show enrichment in waste coals, that may facilitate their co-extraction with the REEs. Concentrations for elements of environmental concern in cleaned coals are similar to or below those for world average coals with the exception of Pb in coals from Illinois. Laser-ablation ICP-MS (LA-ICP-MS) for pyrite in a subset of 21 samples of raw and cleaned coal provided direct determinations of V, Cr, Mn, Co, Ni, Cu, Zn, As, Se, Mo, Ag, Cd, Sb, Au, Hg, Tl, Pb, and Bi. LA-ICP-MS was used together with bulk sample pyritic sulfur and trace element concentrations to estimate the elemental proportion of bulk Cu, As, Hg, and Pb in pyrite, indicating that Hg and Pb are hosted almost entirely by pyrite, whereas the proportion of Cu and As in pyrite accounts for about half of the bulk content. With growing interest in recovering critical elements from coal, partitioning of a large range of elements into waste coals presents a possible opportunity, but also a potential hazard, due to enrichment in harmful elements such as Hg, As, and Pb.

Chemical and molecular scale speciation of copper, zinc, and boron in agricultural soils of the Canadian prairies

The general incidence of copper (Cu), zinc (Zn), and boron (B) deficiencies in soils of the Canadian prairies may be related to identifiable, highly variable, inherent soil attributes. The objective of this study was to investigate the variability of selected properties and their relationship with the bioavailability, forms, and distribution of Cu, Zn, and B in a range of prairie soils. The nature of these micronutrient distributions were evaluated by measuring extractable concentrations, supply rates, and by separation into various chemical pools through sequential extraction and spectroscopic speciation analyses. Soil pH was found to be the least variable property [coefficient of variation (CV) < 13%], whereas carbonate content was the most variable (CV > 130%). The Cu and B availability showed strong negative correlation with the sand content in all soils. Path coefficient results indicated that organic carbon had the highest positive direct effect on availability and supply of Cu and B in Grey soils. Extractable Zn was positively correlated with organic carbon content of Brown and Dark Brown soils. Overall, high sand content and low organic matter were identified as important soil properties contributing to the deficiency of Cu, Zn, and B. The major proportion of Cu, Zn, and B was found in the recalcitrant residual fraction (59%–88%), with the smallest proportions in labile soluble, exchangeable forms (2%–8%). The X-ray absorption near edge structure revealed that Cu and Zn associated with carbonate minerals were dominant forms of these micronutrients present in all soils. Chemisorption is likely a major process regulating the bioavailability of Cu and Zn in prairie soils.

Loading mechanism and double-site reaction mechanism of Cu on activated carbon for enhanced oxidation of CO from flue gas

To strengthen the CO oxidation activity of activated carbon for flue gas purification, AC was modified through acid treatment and metal loading. AC-supported Cu shows excellent catalytic oxidation activity compared with other metal-modified AC samples. To investigate the action modes of Cu loaded on activated carbon and the mechanism of CO oxidation, various samples were characterized by XRD, N2O titration, SEM, N2 physisorption, TPD, H2-TPR, XPS, in situ DRIFTS and EPR. The results show that oxygen-containing functional groups increase the loading amount and dispersion of Cu. Moreover, Cu species strongly bound to oxygen-containing functional groups are the main contributors to CO oxidation. The roles of oxygen-containing functional groups are further revealed: carboxyl groups are the anchoring sites of Cu, and hydroxyl groups supply oxygen to restore the active structure. Similarly, Ce indirectly promote the oxidation activity of CO by re-oxidizing Cu+ to Cu2+, which accelerates the catalytic cycle. The reaction mechanism on AC-supported Cu samples has been proposed to follow the double-site Langmuir–Hinshelwood mechanism, with Cu2+ as oxidation sites, Cu+ as adsorption sites and the formation of oxygen vacancies on Cu+ during the reaction. AC-Cu performs the highest oxidation activity at a proportion of Cu+ of 0.5–0.6. SO2 causes irreversible chemical poisoning to CO oxidation, while NO leads to reversible poisoning due to competitive adsorption with CO. The novel AC-supported Cu catalyst with Ce improves the resistance against SO2 and NO, and the reason is explained. These findings provide theoretical guidance for the preparation and application of metal-modified activated carbon.

An Assessment of Heavy Metal Contamination in the Nakdong River Around the Weir

In this study, the concentrations and characteristics of copper (Cu), zinc (Zn), and lead (Pb) contamination in sediment samples were investigated using aqua regia extraction and Tessier’s five-step sequential extraction. Based on the concentration of metals, the influence of the Hapcheon-Changnyeong weir on sediments in the Nakdong River was assessed. The origins of the contaminants, their bioavailability, and their mobility were determined using sequential extraction. Greater concentrations of heavy metals were found in samples collected closer to the weir. The largest proportion of Cu was identified in the residual fraction based on sequential extraction, whereas Zn was predominantly found in the reducible fraction. Iron-manganese in the reducible fraction of Zn has the potential to leach back to the water body. In addition, the combined concentration of fractions 1 and 2 of Cu comprised more than 20% of total amount that still has potential to affect the water quality. The results of this study were compared with existing sediment standards set out by the NIER (National Institute of Environmental Research), Canada, and US EPA (United States Environmental Protection Agency) guidelines, as well as the risk assessment code (RAC). The concentrations of heavy metals exceeded the standards set by the Canadian guideline by up to four times in particular samples, highlighting the need for continual monitoring.

Copper circuits fabricated on flexible polymer substrates by a high repetition rate femtosecond laser-induced selective local reduction of copper oxide nanoparticles.

In this work, copper circuits were fabricated on flexible polyimide (PI) substrates by high repetition rate femtosecond laser-induced selective local reduction of copper oxide nanoparticles (CuO NPs). The effects of laser pulse energy and laser scanning velocity on the quality of the copper circuit were studied. By optimizing laser processing parameters, we prepared a Cu circuit of a line width of 5.5 µm and an electrical resistivity of 130.9 µΩ·cm. The Cu/O atomic ratio of the Cu circuit reaches ∼10.6 and the proportion of Cu is 91.42%. We then studied the formation mechanism of the copper circuit by simulating the temperature field under the irradiation of high repetition rate femtosecond laser pulses. The results show that the thermochemical reduction reaction induced by the high repetition rate femtosecond laser reduces CuO NPs into Cu NPs. Under the thermal effect of the high repetition rate femtosecond laser, Cu NPs agglomerate and grow to form a uniform and continuous Cu circuit.

Fabrication of Cu(BDC)0.5(BDC-NH2)0.5 metal-organic framework for superior H2S removal at room temperature

A mixed ligand Cu-based MOF, Cu(BDC)0.5(BDC-NH2)0.5 was synthesized by a rapid ultrasonication method for the adsorptive removal of hydrogen sulfide (H2S) gas at room temperature. The MOF has a sheet-like morphology with 100 nm thickness crystallized in the monoclinic symmetry (a = 11.27 Å, b = 14.82 Å, c = 7.95 Å, β = 110.8°) with C2/m space group. The surface area and pore volume was 19.4 m2 g−1 and 0.024 cm3 g−1, respectively. The XPS analysis confirmed a near equal proportion of Cu(I) and Cu(II)-sites in the MOF. The MOF showed the H2S adsorption capacity of 128.4 mg g−1 for 500 ppm of H2S flowing at a rate of 100 mL min−1, which is among the highest values reported for Cu-based MOFs. The spent MOF was regenerated by a methanol and UV-irradiation method, which significantly improved the adsorption capacity. The H2S adsorbed onto the MOF by breaking Cu-carboxylate bonds with the formation of covellite CuS nanoparticles and sulfates. The spectroscopic analysis predicted a Cu(OH)-type sites after UV-irradiation along with increased surface area, which were responsible for an enhanced adsorption capacity of the regenerated sample.

Permittivity order modulation by intrinsic dielectric coupling

The room-temperature permittivity is reduced by one order of magnitude in a wide frequency range during each step, when the stoichiometric proportion of Cu in CaCu3Ti4O12 is decreased from 3 to 2 and then to 1. The frequency-independent reduction can be applied down to 140 K. Such an almost frequency- and temperature-independent decrease in the permittivity magnitude order suggests the existence of intrinsic dielectric coupling between binary dielectric polarization species, by which the less polaron-like 3d electrons from B-site copper ions more strongly depress the permittivity contribution from one-dimensional, anti-parallel, mutually independent, and finite length dipole chains of thermally activated off-center displacements of A-site titanium ions.

公路源重金属对青藏高原高寒草甸土壤线虫群落的影响

为了解重金属对青藏高原高寒草甸土壤线虫群落的影响，在邦杰塘草原利用公路源重金属含量差异，采用高通量测序技术，分析重金属对高寒草甸土壤线虫群落多样性及群落组成的影响。结果表明：在重金属含量较低样本中，土壤线虫群落Shannon指数、Ace指数、Chao指数比重金属含量较高样本均要小，且整体上Shannon指数、Ace指数、Chao指数与重金属含量较高样本差异显著（P<0.05）。重金属含量升高改变了高寒草甸土壤线虫纲水平和目水平的群落结构，使近自然状况下的色矛纲（Chromadorea）、小杆目（Rhabdtida）优势土壤线虫群落转变为一类未分类线虫纲（unclassified_p_Nematoda）、一类未分类线虫目（unclassified_p_Nematoda）的优势土壤线虫群落。重金属Cu、Pb、Zn、Cd与线虫门（Nematoda）和刺嘴纲（Enoplea）正相关，但与色矛纲（Chromadorea）负相关，且对土壤线虫Chao指数的变异解释比例依次减小。研究表明土壤重金属含量对青藏高原高寒草甸土壤线虫群落多样性及组成产生很大影响，但仍需对高寒草甸区域进行系统的土壤线虫调查，并丰富土壤线虫生物信息数据库。;Soil nematode is a sensitive soil organism. In order to understand the effects of heavy metals on the alpine meadow soil nematode community in the Tibet Plateau, this study based on the differences in heavy metals content from highway sources in the Bangjietang grassland used the high-throughput sequencing technology to analyze the influence of heavy metals on the diversity and community structure of the alpine meadow soil nematode community. In August 2019, we collected soil samples at 0, 5, 15, 30, 50 and 75 m away from the highway in Bangjietang grassland. Cu, Pb, Zn, Cd were determined by flame atomic absorption spectrophotometry, and the community composition and structure of soil nematode were determined by high-throughput sequencing technology. The influence of heavy metals on soil nematode community was discussed by redundancy analysis. The results showed that the Shannon index, Ace index and Chao index of the soil nematode community in the samples with lower heavy metal content were smaller than the samples with higher heavy metal content (P<0.05). The increase of heavy metal content changed the community structure of soil nematode in alpine meadow, and the dominant soil nematode communities of Chromadorea and Rhabdtida under the natural conditions were transformed into the dominant soil nematoda communities of unclassified_p_Nematoda and unclassified_p_Nematoda. Cu, Pb, Zn and Cd were positively correlated with Nematoda and Enoplea, but negatively correlated with Chromadorea. The proportion of Cu, Pb, Zn, Cd to the variation explanation of Chao index decreased successively. The study shows that soil heavy metal content has a great influence on the diversity and structure of soil nematode community in alpine meadow of the Tibet Plateau, but it is still necessary to conduct a systematic investigation of soil nematode in alpine meadow and enrich the database of biological information of soil nematode.

Single and Sequential Extraction of Copper by Different Extractants from Different Peat Soil Samples of Bangladesh

A comprehensive in vitro study on single and sequential extraction methods for Cu exraction by different extractants of distinct chemical nature from some peat soils of Bangladesh was conducted to assess the pattern of metal-extractability in drying and wetting sequences. Samples were collected from peat basins of two different districts of Bangladesh (Gopalgonj and Bagerhat) and an incubation study was designed and conducted in which soils were incubated to three alternate drying and wetting cycles for 21 days. Single and sequentially extracted Cu ions in all three cycles and by all three selective extractants were compared. Maximum amount of Cu was extracted in drying days and 1M HCl extracted the largest proportion of Cu from all the soils in each incubation time. Conversely, 1M NH4Cl was the least effective extractant for extracting Cu by both single and sequential process in either day of incubation. Considerable amount of Cu was extracted by 0.005 M DTPA in dry periods. In general, single extraction was found to be more effective in extracting Cu in the alternate drying and wetting cycles from the peat soil samples except for 1M HCl in initial drying days.

Research on the nucleation and growth of high-entropy alloy

In this work, we studied the composition evolution of nucleus during the solidification process of CoCrCuFeNi high-entropy alloy at the nanosize scale with molecular dynamics simulation. We find that the composition in the early-stage nucleus deviates greatly from the composition of system: the proportion of Fe is much higher than other elements, the proportions of Co and Ni are close to 20%, the proportion of Cr is lower than 20%, and the proportion of Cu is the lowest. This phenomenon is closely related to the local chemical order of the system during the solidification process. Additionally, our research clarified the origin well for the formation of Cu-rich phase and Cu-depleted phase observed in the experiments.

PSXII-13 The influence of trace mineral source on copper, manganese, and zinc binding strength to rumen digesta in cattle fed a high forage-based diet

Abstract Twelve crossbred Angus steers fitted with rumen cannulae were used to determine the influence of trace mineral source on ruminal soluble mineral concentrations and relative binding strength of trace minerals in the ruminal insoluble digesta fraction. Steers were adjusted to a low-quality hay (chopped) diet balanced to meet the nutrient requirements for growing steers. For 7 d prior to initiation of the study, steers were fed the diet without supplemental Cu, Mn, and Zn. On day 8 steers received a pulse dose (2 x NRC requirement) of Cu, Mn, and, Zn from sulfate (STM) or hydroxy trace minerals (HTM; Micronutrients LLC, USA). Ruminal samples were obtained at 2 h intervals until 24 h post-dosing for soluble (fraction obtained after centrifugation) Cu, Mn, and Zn concentrations. Binding strength of Cu, Mn, and Zn to ruminal solid digesta (post centrifugation) was estimated at 0, 12, and 24h post-dosing using dialysis against 0.05 M Tris-EDTA. Ruminal soluble mineral concentrations were greater (P &amp;lt; 0.05) for Cu at 4, 6, 8, 10, 12, and 16 h; for Mn at 4 and 6 h; and for Zn at 4, 6, and 8 h post dosing in STM compared to HTM steers. Concentration of Cu, Mn, and Zn remaining in the insoluble fraction were greater (P &amp;lt; 0.05) at 12 h post dosing in HTM vs STM supplemented steers. At 24 h post dosing, Mn concentrations were lesser (P &amp;lt; 0.03) and Zn concentrations were greater (P &amp;lt; 0.001) in HTM vs STM supplemented steers. Following dialysis, the % Cu, and Zn released from the insoluble fraction was greater (P &amp;lt; 0.001) at 12 h and 24h in HTM vs. STM supplemented steers. Results indicate that a greater proportion of Cu and Zn HTM remained loosely bound to the insoluble fraction within the rumen.

In Situ Preparation of Copper-Loaded Carbon-Based Catalyst with Chelate Resin and Its Application on Persulfate Activation for X-3B Degradation

Under the guidance of the idea of “treating waste with waste”, copper-loaded carbon-based catalysts were prepared in situ using waste chelating resin with adsorbed copper. The effect of the catalyst activation temperature on dye brilliant red (X-3B) degradation was investigated and the characterization of the catalysts was analyzed. The results show that a catalyst activated at 800 °C (Cu-AC-800) has the largest specific surface area and abundant pore structure and the highest proportion of Cu under low valence states, which leads to the best performance in adsorbing and degrading X-3B. The influences of operation conditions and inorganic salt anions on persulfate (PS) activation were also investigated. Moreover, the degradation mechanism was preliminarily explored by quenching reactions. The main active free radicals in the system were determined as sulfate radicals (•SO4−). Given its use in solid waste recycling, copper-loaded carbon-based catalyst may provide some new insights for the remediation of wastewater.

Fractionation and mobility of copper, cadmium, and lead in some soil irrigated with sewage water in Qena governorate, upper Egypt

This study was conducted to investigate the chemical fractionation and mobility of Cu, Cd and Pb in some soil irrigated with sewage water in Qena governorate, Upper Egypt. Sequential extraction results showed that in the treated soil, a major proportion of Cu, Pb, and Cd was associated with poorly crystalline iron oxide bound (PCFeOX), crystalline iron oxide – occluded (CFeOX) and a major proportion of Cu, Pb and Cd was associated with residual (RES) fractions. Based on relative percent. the results also show that The non-labile Cu, Cd and Pb in the non-irrigated soil partially transformed to the potentially labile Cu due to the irrigation with sewage water Also, a part of the readily labile and potentially labile Cu, Cd and Pb of the sewage water irrigated soils for short time transformed to the non-labile fraction with irrigation with same water for a long time. Higher mobility of metals in the soils irrigated with sewage water for short time represent a potential hazard for the redistribution and translocation of these metals into the food chain and leach to ground water.

Solvothermal synthesis of copper-doped BiOBr microflowers with enhanced adsorption and visible-light driven photocatalytic degradation of norfloxacin

Photocatalysts based on copper-doped bismuth oxybromide (Cu-doped BiOBr) were synthesised using a solvothermal method and assessed for their ability to degrade norfloxacin under visible light. The Cu atoms were successfully doped into the crystal lattice of BiOBr, yielding Cu-doped BiOBr microflowers with a morphology and crystal structure identical to that of pristine BiOBr. The as-prepared Cu-doped BiOBr showed activity superior to BiOBr in the photocatalytic degradation of norfloxacin under visible-light irradiation, which was attributed to its improved light-harvesting properties, enhanced charge separation and interfacial charge transfer. Furthermore, we found for the first time that the introduction of Cu into BiOBr enhanced the adsorption capacity between the photocatalyst and norfloxacin, which we considered to be the main contribution to its improved performance. Cu-doped BiOBr containing the optimal proportion of Cu and Bi (Cu:Bi = 0.03) had a photocatalytic degradation constant of 0.64 ×10−2 min−1, which is 2.28 times higher than that of undoped BiOBr. The primary oxidation pathway was determined to involve the transfer of photogenerated holes to norfloxacin. Finally, we demonstrated that the Cu-doped BiOBr photocatalyst retained 95% of its initial activity even after five successive catalytic cycles, confirming its recyclability.