Recovery of Cu(II) by chemical reduction using sodium dithionite: effect of pH and ligands

2015 ◽  
Vol 72 (11) ◽  
pp. 2089-2094 ◽  
Author(s):  
Yi-Hsuan Chou ◽  
Jui-Hsuan Yu ◽  
Yang-Min Liang ◽  
Pin-Jan Wang ◽  
Chi-Wang Li ◽  
...  
Keyword(s):  
Metal Removal ◽  
Ethylenediaminetetraacetic Acid ◽  
Chemical Reduction ◽  
Metallic Copper ◽  
Sample Pretreatment ◽  
Copper Removal ◽  
Experimental Result ◽  
Molar Ratio ◽  
Metallic Nanoparticle ◽  
Industrial Sectors

Wastewaters containing Cu(II) and ligands are ubiquitous in various industrial sectors, and efficacy of copper removal processes, especially precipitation, is greatly compromised by ligands. Chemical reduction, being commonly employed for production of metal nanoparticles, is also effective for metal removal. Adjustment of pH and addition of ligands are important to control the particle size in metallic nanoparticle production. Exploiting the fact that ligands and metals coexist in many wastewaters, chemical reduction was employed to treat ligand-containing wastewater in this study. The experimental result shows that depending on pH, type of ligands, and copper:ligand molar ratio, copper could be removed by either the reduction or precipitation mechanism. Almost complete copper removal could be achieved by the reduction mechanism under optimal condition for solutions containing either EDTA (ethylenediaminetetraacetic acid) or citrate ligands. For solutions containing ammonia, depending on pH and Cu:ammonia molar ratio, copper was removed by both precipitation and reduction mechanisms. At pH of 9.0, formation of nano-sized particles, which readily pass through a 0.45 μm filter used for sample pretreatment before residual copper analysis, results in the lowest copper removal efficiency. Both cuprous oxide and metallic copper are identified in the solids produced, and the possible explanations are provided.

Integration of polyelectrolyte enhanced ultrafiltration and chemical reduction for metal-containing wastewater treatment and metal recovery

2015 ◽  
Vol 72 (7) ◽  
pp. 1096-1101 ◽  
Author(s):  
Jui-Hsuan Yu ◽  
Yi-Hsuan Chou ◽  
Yang-Min Liang ◽  
Chi-Wang Li
Keyword(s):  
Removal Efficiency ◽  
Ph Value ◽  
Chemical Reduction ◽  
Sample Pretreatment ◽  
Particle Size Analysis ◽  
Reduction Reaction ◽  
Copper Removal ◽  
Molar Ratio ◽  
Size Analysis ◽  
Copper Particles

Chemical reduction was firstly employed to treat synthetic wastewaters of various compositions prepared to simulate the retentate stream of polyelectrolyte enhanced ultrafiltration (PEUF). With fixed Cu:polyethylenimine (PEI) monomer:dithionite molar ratio, increasing copper concentration increases copper removal efficiency. Under fixed Cu:dithionite molar ratio and fixed Cu concentration, increasing PEI monomer:copper molar ratio decreases copper removal efficiency. The formation of nano-sized copper particles, which readily pass through 0.45 μm filter used for sample pretreatment before residual copper analysis, might be the reason behind the decreasing copper removal efficiency observed. Particle size analysis shows that the size of copper particles, which are formed through reduction reaction, increases with decreasing pH value and increasing reaction time. As ultrafiltration is capable of removing these nano-sized particles, integration of chemical reduction and PEUF is proposed to simultaneously achieve regeneration of polyelectrolyte and recovery of copper in one process. Results show that the proposed process could achieve almost complete copper removal without being affected by reaction pH.

scholarly journals New Hybrid Copper Nanoparticles/Conjugated Polyelectrolyte Composite with Antibacterial Activity

Polymers ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 401
Author(s):  
Ignacio A. Jessop ◽  
Yasmín P. Pérez ◽  
Andrea Jachura ◽  
Hipólito Nuñez ◽  
Cesar Saldías ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Copper Nanoparticles ◽  
Salmonella Enteritidis ◽  
Theoretical Calculations ◽  
Chemical Reduction ◽  
Metallic Copper ◽  
Resistant Bacteria ◽  
Small Contribution ◽  
Antibiotic Resistant ◽  
Conjugated Polyelectrolyte

In the search for new materials to fight against antibiotic-resistant bacteria, a hybrid composite from metallic copper nanoparticles (CuNPs) and a novel cationic π-conjugated polyelectrolyte (CPE) were designed, synthesized, and characterized. The CuNPs were prepared by chemical reduction in the presence of CPE, which acts as a stabilizing agent. Spectroscopic analysis and electron microscopy showed the distinctive band of the metallic CuNP surface plasmon and their random distribution on the CPE laminar surface, respectively. Theoretical calculations on CuNP/CPE deposits suggest that the interaction between both materials occurs through polyelectrolyte side chains, with a small contribution of its backbone electron density. The CuNP/CPE composite showed antibacterial activity against Gram-positive (Staphylococcus aureus and Enterococcus faecalis) and Gram-negative (Escherichia coli and Salmonella enteritidis) bacteria, mainly attributed to the CuNPs’ effect and, to a lesser extent, to the cationic CPE.

Synthesis and Infrared Spectrum Characterization of Phenylalanine Chelated Calcium Complex

2011 ◽  
Vol 396-398 ◽  
pp. 1549-1553
Author(s):  
Yu Qi Wu ◽  
Lian Jin Weng ◽  
Yuan Yuan Han ◽  
Xin Yang ◽  
Di Geng
Keyword(s):  
Infrared Spectrum ◽  
Chelate Ring ◽  
Uniform Design ◽  
Water System ◽  
Experimental Result ◽  
Molar Ratio ◽  
Optimal Parameters ◽  
Single Factor ◽  
Preparation Conditions

The preparation conditions in the water system of phenylalanine chelated calcium complex have been evaluated though single-factor tests and optimized by uniform design. Then the optimal parameters were obtained as follows: reaction temperature is 40 °C, reaction time is 182 min, the molar ratio of phenylalanine to calcium is 4.3 and pH = 9.0. Under the best conditions, the experimental result gives chelating rate = 87.40% that is 17.12% lower than the prediction = 104.52%.The infrared spectrum characterization has confirmed the formation of phenylalanine-Ca2+ chelates and the existence of chelate ring.

The application of wetland technology for copper removal from distillery wastewater: a case study

2009 ◽  
Vol 60 (11) ◽  
pp. 2759-2766 ◽  
Author(s):  
C. Murphy ◽  
P. Hawes ◽  
D. J. Cooper
Keyword(s):  
Metal Removal ◽  
Copper Removal ◽  
Ionic Form ◽  
Reed Beds ◽  
Organic Species ◽  
Treatment Processes ◽  
Distillery Wastewater ◽  
Reed Bed ◽  
Performance Results

The ability of reed beds to remove significant levels of metals from effluent streams is well cited in the literature. Various methods of removal have been postulated and demonstrated including physical methods such as filtration and settlement, precipitation when the metal is present as a salt and adsorption to organic species or take up by macrophytes when the metal is in a soluble or ionic form. Consequently, reed beds have been used in a variety of applications for metal removal in water treatment processes. The distillation process for whisky generates an effluent containing a significant amount of copper which is scoured from the copper stills during the process and cleaning operations. High soluble copper concentrations can breach discharge consents. A horizontal subsurface flow reed bed system has been designed and installed for copper removal at a distillery in Scotland. This paper presents the findings of the literature search, outlines the design of the bed and reviews the performance results.

Fly ash based geopolymer for heavy metal removal: A case study on copper removal

2015 ◽  
Vol 3 (3) ◽  
pp. 1669-1677 ◽  
Author(s):  
Mohammad S. Al-Harahsheh ◽  
Kamel Al Zboon ◽  
Leema Al-Makhadmeh ◽  
Muhannad Hararah ◽  
Mehaysen Mahasneh
Keyword(s):  
Heavy Metal ◽  
Fly Ash ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Copper Removal

Optimization and statistical analysis of sono-Fenton treated wastewater of food industry using reactor by response surface method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod
Keyword(s):  
Reaction Time ◽  
Response Surface ◽  
Food Industry ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Experimental Result ◽  
Molar Ratio

Abstract The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).

scholarly journals Sol-Gel Immobilisation of Lipases: Towards Active and Stable Biocatalysts for the Esterification of Valeric Acid

Molecules ◽  
2018 ◽  
Vol 23 (9) ◽  
pp. 2283 ◽  
Author(s):  
Soledad Cebrián-García ◽  
Alina Balu ◽  
Araceli García ◽  
Rafael Luque
Keyword(s):  
Microwave Irradiation ◽  
Sol Gel ◽  
Valeric Acid ◽  
Added Value ◽  
Conventional Heating ◽  
Molar Ratio ◽  
Highly Active ◽  
Industrial Sectors ◽  
Wide Range ◽  
Acid Esterification

Alkyl esters are high added value products useful in a wide range of industrial sectors. A methodology based on a simple sol-gel approach (biosilicification) is herein proposed to encapsulate enzymes in order to design highly active and stable biocatalysts. Their performance was assessed through the optimization of valeric acid esterification evaluating the effect of different parameters (biocatalyst load, presence of water, reaction temperature and stirring rate) in different alcoholic media, and comparing two different methodologies: conventional heating and microwave irradiation. Ethyl valerate yields were in the 80–85% range under optimum conditions (15 min, 12% m/v biocatalyst, molar ratio 1:2 of valeric acid to alcohol). Comparatively, the biocatalysts were slightly deactivated under microwave irradiation due to enzyme denaturalisation. Biocatalyst reuse was attempted to prove that good reusability of these sol-gel immobilised enzymes could be achieved under conventional heating.

scholarly journals Electrodeposition behaviour of copper from ore leachate and copper ammonium sulphate

2020 ◽  
Vol 55 (3) ◽  
pp. 229-236
Author(s):  
AI Ambo ◽  
HJ Glassa ◽  
C Peng
Keyword(s):  
Electron Transfer ◽  
Ammonium Sulphate ◽  
Redox Reaction ◽  
Chemical Reduction ◽  
Metallic Copper ◽  
Electron Transfer Reaction ◽  
Single Electron ◽  
Electrochemical Kinetics ◽  
Electron Transfer Processes ◽  
Copper Ammonium

The deposition behaviour of copper ammonia complexes from ore leachate and synthetic copper ammonium sulphate solutions was investigated using cyclic voltammetrywith platinumas counter electrode. The work is carried out to understand the deposition behaviour of the ore for hydrometallurgical and electro winning application. The chemical reduction and deposition of copper from both solutions consisted of two reversible electrochemical processes, each involving the transfer of a single electron. The Cu(NH3)4 2+ complex in the copper leachate is first reduced to Cu(NH3)4 + before being reduced to metallic copper. With synthetic copper ammonium sulphate (Cu(NH3)4SO4), the reduction to metallic copper is a ligand-coupled electron transfer reaction which proceeds as two sequential, single-electron transfer processes. The Cu/Cu(NH3)4 2+ redox reaction during deposition of copper from the leachate is fast compared to that of the Cu/Cu2+ redox reaction in the Cu(NH3)4SO4 synthetic solution. Investigation of the electrochemical kinetics shows that the linear relationship between the peak current and the square root of the scan rate is an indication that the Cu(NH3)4 + and Cu(NH3)4SO4 reduction to Cu proceeds through a diffusion-controlled process. Bangladesh J. Sci. Ind. Res.55(3), 229-236, 2020

scholarly journals The Anodic Behaviour of Bulk Copper in Ethaline and 1-Butyl-3-Methylimidazolium Chloride

2019 ◽  
Vol 9 (20) ◽  
pp. 4401 ◽  
Author(s):  
Karim ◽  
Aziz ◽  
Brza ◽  
Abdullah ◽  
Kadir
Keyword(s):  
Electrochemical Impedance ◽  
Choline Chloride ◽  
Metallic Copper ◽  
Electrochemical Techniques ◽  
Deep Eutectic Solvent ◽  
Molar Ratio ◽  
Interfacial Region ◽  
Dissolution Mechanism ◽  
Spectroscopic Techniques ◽  
Electrochemical Dissolution

The anodic dissolution of bulk metallic copper was conducted in ionic liquids (ILs)—a deep eutectic solvent (DES) ((CH3)3NC2H4OH) comprised of a 1:2 molar ratio mixture of choline chloride Cl (ChCl), and ethylene glycol (EG)—and imidazolium-based ILs, such as C4mimCl, using electrochemical techniques, such as cyclic voltammetry, anodic linear sweep voltammetry, and chronopotentiometry.To investigate the electrochemical dissolution mechanism, electrochemical impedance spectroscopy (EIS) was used. In addition to spectroscopic techniques, for instance, UV-visible spectroscopy, microscopic techniques, such as atomic force microscopy (AFM), were used. The significant industrial importance of metallic copper has motivated several research groups to deal with such an invaluable metal. It was confirmed that the speciation of dissolved copper from the bulk phase at the interface region is [CuCl3]− and [CuCl4]2− in such chloride-rich media, and the EG determine the structure of the interfacial region in the electrochemical dissolution process. A super-saturated solution was produced at the electrode/solution interface and CuCl2 was deposited on the metal surface.

scholarly journals Hydroxyapatite/Silver Nanoparticles Powders as Antimicrobial Agent for Bone Replacements

2019 ◽  
Vol 92 (1) ◽  
pp. 59-68 ◽  
Author(s):  
Agnieszka Sobczak-Kupiec ◽  
Dagmara Malina ◽  
Regina Kijkowska ◽  
Wioletta Florkiewicz ◽  
Klaudia Pluta ◽  
...  
Keyword(s):  
Ag Nanoparticles ◽  
Chemical Reduction ◽  
Absorption Spectrometry ◽  
Bactericidal Effect ◽  
Sem Analysis ◽  
Biological Assessment ◽  
Molar Ratio ◽  
In Situ Deposition ◽  
Morphological Modification ◽  
Xrd Techniques

This paper reports a superficial morphological modification of the hydroxyapatite grains obtained by in situ deposition of Ag nanoparticles on natural origin calcium phosphate powder. Ceramic material was prepared in three stage bone treatment, including hydrolysis with a lactic acid, pre-calcination, and proper calcination. Subsequently, the Ag nanoparticles were synthesized by chemical reduction of Ag+ by sodium borohydride in a solution of polyvinylpyrrolidone and in presence of hydroxyapatite. Such-prepared materials were investigated with X-ray diffraction, Fourier-transformed infrared spectroscopy, atomic absorption spectrometry and scanning electron microscopy with energy dispersive spectroscopy. Furthermore, Ca/P molar ratio was calculated and microbiological tests were performed to investigate materials antimicrobial activity. The appearance of Ag nanoparticles located on phosphate surface was confirmed by SEM analysis, and no chemical bonding with hydroxyapatite was recorded by IR and XRD techniques. Additionally, the biological assessment revealed bactericidal effect on Escherichia coli and Staphylococcus aureus, while slightly affected on Enterococcus faecalis viability.

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