Papers by Keyword: Copper (Cu)

Abstract: The present study was conducted to establish adsorbent potential of magnetite nanoparticle ferrous ferric oxide (Fe₃O₄) for removal of Cu(ll) ions in wastewater. In the study, Fe₃O₄ was prepared by synthesizing low-cost recycled mill scale waste in an aqueous solution. Samples of scale wastes were milled and ground using high-energy ball milling (HEBM) at three milling times of 5, 7 and 9 hours. Extraction of Fe₃O₄ was accomplished by magnetic separation technique (MST) and Curie temperature separation technique (CTST). The morphologies and structural properties of Fe₃O₄ were characterized by using X-ray powder diffraction (XRD), high-resolution transmission electron microscopy (HRTEM) and Fourier-transform infrared spectroscopy (FTIR). HRTEM yielded images in the range of 10-22 nm. Maximum adsorption capacity, q_e, and percentage removal of Cu(II) ions were achieved at 4.45 mg/g and 62.61% respectively after 7 hours of milling time. The present study recorded the smallest particle size of Fe₃O₄ imparting high qe, and percentage removal of Cu (II) ion in an aqueous solution, suggesting its high adsorbent potential.

Abstract: This study was aimed to determine the effect of electro-assisted and oxygen injection system to improve the effectiveness of the copper and iron removal in wastewater by phytoremediation system. The electro-assisted phytoremediation (EAPR) system was run with Vetiver grass (Vetiveira zizanioides L) as accumulator plant and 2 V of constant DC power supply using 2D cathode-pot electrode and air diffuser configuration on the aeration by air flow rate of 10 L/min. The effectiveness of phytoremediation, phyto-aeration,and phytoremediation on the wastewater treatment was compared and evaluated by measuring the decreasing of heavy metal concentration in the wastewater and accumulated inthe plant. Plant stress was monitored by the observation of phytomorphology changed and measurement chlorophyll content using UV-Vis Spectroscopy after the acetone extraction and heavy metal concentration was measured by Flame-Atomic Absorption Spectroscopy (Flame-AAS). The results showed that the decreasing of Cu and Fe concentration in the wastewater as much as 86.5% and 99,3%, higher than that phyto-aeration (82.35% and 99.20%) and phytoremediation (15.0% and 56.0%). The uptake profiles of heavy metal by plant indicated the enhancement ability of electro-assisted and aeration system to the phytoremediation has different results. For example in the root part, the heavy metal absorption occurred most often as following in phytoremediation>phyto-aeration>EAPR-aeration. Contrary results show in the EAPR-aeration system that the metal concentration quiet high translocation from root to shoot part by enhancement of electro-assisted and aeration system. High chlorophyll content and chlorophyll ratio in the plant under the EAPR-aeration system shows higher tolerance of the plant to the heavy metal concentration.

Abstract: Nodular infinite chilled iron (NICI) material with high content of nickel (~4.00%) was usually used as work roll in hot strip rolling mill. Microstructure of NICI was consists with nodular graphite and cementite with matrix phase consist of pearlite, martensite and ausferrite that depend on the alloying content. The introduction of copper was successfully increasing the hardenability of NICI by only using low nickel content (~2.50 %) with small addition of copper (0.52%). The development of NICI was done by hot shakeout of CO2 sand mold of as-cast iron and then isothermal heating in muffle furnace in temperature 300 oC in 6 hours to achieve ausferritic transformation. By achieving the martensite and ausferrite phase in as-cast condition, the sample will not need austenitizing and quenching process and the sample that will be free of quenching crack and thermal stress that usually occurred austenitizing and quenching process. It was confirmed by optical microscope and scanning electron microscope (SEM) observations that with the small addition of copper (0.52%), the amount of pearlite was very small (~1.00%), but with further addition of copper (2.02%), the amount of martensite was significantly increase the hardness until 51.56 HRC but the tensile strength was significantly dropped into 442 Mpa from previously 571 Mpa without copper addition. From hardness and tensile strength data it can be seen that the optimum content of copper is 1.45 % that have good combination of hardness (47.75 HRC) and moderate tensile strength (508 Mpa).

Abstract: The matrix structure formation of cast irons is strongly affected by the casting process where different alloying elements and cooling conditions are methods used to achieve the desired structure and performance of the material. In the presented study, six pearlitic grey cast irons have been analysed regarding how the pearlitic structure formation might be controlled. Different amounts of copper and chromium were added, ranging from 0.07 to 1.11 wt% and 0.08 to 0.60 wt%, respectively. Three different section sizes (Ø20, Ø45 and Ø85 mm) and three different cooling conditions through the eutectoid transformation were used to control the matrix structure formation. The three different cooling conditions were achieved by shake-out at 950°C and cooling in air or furnace, or by keeping the casting in the mould. The present paper focuses on the pearlite appearance, since it strongly affects the mechanical properties. The analysis shows that the refining effect of Cr is much stronger than that of Cu. Comparing the low alloyed base melt with the ones alloyed with Cu and Cr, it is seen that additions of 0.75 wt% Cu refines the pearlite by approximately 10%. Keeping this Cu level constant and adding Cr, it is observed that an addition of ~0.6 wt% refines the pearlite by another 20%. The most potent refining effect of Cr is achieved by additions up to 0.35 wt%. Keeping the Cr constant at 0.35% and changing the Cu content (0.35 to 1.10 wt%), almost no variation is observed in the overall interlamellar spacing. The eutectoid cooling rate most strongly affects the interlamellar spacing down to cooling rates of about -0.75 °C/s. At higher (i.e. lower value) cooling rates the interlamellar spacing is fairly constant. In addition to studying the interlamellar spacing, the graphite structure has also been analysed and evaluated concerning effects from the different casting variables.

Abstract: Fatigue life of smooth specimens is approximately controlled by the growth life of a small crack. This means the growth behavior of small cracks must be clarified to estimate the fatigue life of plain members. However, there are few studies on the growth behavior of small cracks in ultrafine grained (UFG) metals. In the present study, fatigue tests for UFG copper have been conducted. The formation behavior of shear bands (SBs) and growth behavior of a small crack have been monitored to clarify the effect of SBs on the growth behavior of a major crack.

Abstract: Recently, a few studies have been undertaken for the extracting of metallic copper from electronic scrap/printed circuit boards by bioleaching - solvent extraction-electrowinning. Results of the present investigation indicate that bioleaching-solvent extraction-electrowinning could be a new cleaner hydrometallurgy route for recovery copper from the PCBs.The life cycle assessment method was used to investigate the environmental impacts of the new biohydrometallurgical process of production of metallic copper. The energy consumption，greenhouse effect，acidification in the new processes is studied and compared. The results indicate that the environmental impacts of bioleaching - solvent extraction-electrowinning technology is less than the conventional mechanical-pyrometallurgical processes and pyrometallurgical processes.

Abstract: The individual and competitive adsorption capacities of Pb2+, Cu2+ and Zn2+ on clinoptilolite and polymeric Al/Fe modified clinoptilolite were studied. In single systems, adsorption capacity of Pb2+ exceeded that of Cu2+ and Zn2+, and the adsorption capacities of Pb2+, Cu2+ and Zn2+ by polymeric Al/Fe modified clinoptilolite were greater than clinoptilolite. In binary isometric competition adsorption, adsorption capacities of Pb2+, Cu2+ and Zn2+ by clinoptilolite and polymeric Al/Fe modified clinoptilolite decreased compared with single systems. In binary non -isometric competition adsorption, adsorption of Zn2+ from solutions containing a fixed Zn2+ concentration was severely depressed (34%, 26% by clinoptilolite and polymeric Al/Fe (PAFC) modified clinoptilolite, respectively) by increasing the concentration of Cu2+ in the solution, but inverting the roles of Cu2+ and Zn2+ caused only a relatively minor reduction in adsorption of Cu2+. What,s more in other non-equal competition binary systems, the effect of metal adsorption was little. In general, the strength of adsorption followed the order of Pb2+ > Cu2+ > Zn2+ and the order of PAFC modified clinoptilolite > clinoptilolite.

Abstract: This paper investigated the antibacterial mechanism of the Cu-antibacterial White Carbon Black containing cerium. The sol-gel method was used to prepare the White Carbon Black carrier. Cu2+ was selected to be the antibacterial ion, and cerous nitrate was selected to be the additive. They were synthesized on the white carbon black carrier. The structure and antibacterial mechanism of antibacterial material were characterized by inductively coupled plasma, Fourier transform infrared spectroscopy and enumeration tests (Escherichia coli as experimental bacterium). Results showed that the contents of antibacterial ions in the Cu-antibacterial white carbon black containing cerium were higher than those for the general Cu-antibacterial white carbon black (without containing cerium). Cu2+ was bound to white carbon black by ion exchange process. Bacteriostasis rate is over 99%. Furthermore, other advantages of this material are its good thermal and light stabilities.

Abstract: Cu-Zn alloy was prepared by high energy ball milling of elemental copper and zinc, With the Simoloyer attrition mill the particle around 10µm with good particle-size distributions can be made in 100 min. Through the analysis by TG-DTA, XRD, SEM, the results show that Cu-Zn alloys can be produced by ball milling without the formation of oxide even milling in the air atmosphere and subsequent heat treatment at 350°C, it indicated that the formation of the oxide can be avoided during ball milling by adding Al.

Abstract: The corrosion inhibition of copper in 3% NaCl solution by 3-amino-1, 2, 4-triazole (ATA) has been studied in relation to the concentration of the inhibitor using electrochemical (AC impedance and dc polarization) techniques. The results indicate that ATA has good corrosion inhibition for copper in 3% NaCl solution. The inhibition efficiency attains the maximum value of 97.65% when the concentration of ATA is 20 mg•L-1.Polarisation curves show that ATA behaves as a type of cathodal inhibition in 3% NaCl solution. Adsorption of the ATA is found to follow the Langmuir’s adsorption isotherm, and the adsorption mechanism is typical of chemisorption.