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Copper oxide

Copper oxides are inorganic compounds consisting of copper and oxygen, primarily existing in two stable forms: copper(I) oxide (Cu₂O), a red crystalline solid, and copper(II) oxide (CuO), a black or brownish-black powder.^[1]^[2] These compounds occur naturally as minerals—Cu₂O as cuprite and CuO as tenorite—and are produced industrially through oxidation of copper or precipitation reactions.^[3] Both are insoluble in water but dissolve in acids and certain ammoniacal solutions, exhibiting semiconductor properties that enable their use in electronics and catalysis.^[1]^[2] Copper(I) oxide (Cu₂O) has a molecular formula of Cu₂O, a molecular weight of 143.09 g/mol, a density of 6.0 g/cm³, and melts at 1232–1235 °C without decomposition.^[1] It appears as red-brown cubic crystals and is widely employed as a pigment in ceramics, glasses, and paints, as well as a fungicide, antifouling agent in marine coatings, and semiconductor in solar cells and batteries.^[1]^[3] In contrast, copper(II) oxide (CuO) features the formula CuO, a molecular weight of 79.55 g/mol, a density of 6.315 g/cm³, and decomposes at approximately 1030 °C without melting.^[2] This form serves as a catalyst in chemical reactions, a pigment in porcelain glazes, a precursor for rayon production, and an ingredient in batteries, superconductors, and wood preservatives.^[2]^[3] Both copper oxides play critical roles in modern applications due to their redox properties, though they pose environmental risks such as toxicity to aquatic life.^[1]^[2] Recent research highlights their potential in nanotechnology, including nanoparticles for antimicrobial agents, gas sensors, and energy storage devices, leveraging their bandgap energies—approximately 2.1 eV for Cu₂O and 1.2–1.7 eV for CuO.^[4]^[3]

Overview

Nomenclature and types

Copper oxides are inorganic compounds composed of copper and oxygen atoms, with the two primary stable forms being copper(I) oxide, represented by the chemical formula Cu₂O (molar mass 143.09 g/mol), and copper(II) oxide, represented by CuO (molar mass 79.55 g/mol).^[1]^[5] In Cu₂O, copper adopts the +1 oxidation state (Cu(I)), while in CuO it is +2 (Cu(II)); these are the predominant stable oxidation states for copper in oxide compounds due to the d¹⁰ electronic configuration of Cu(I) and the favorable stability of the d⁹ configuration in Cu(II), rendering higher states such as Cu(III) or Cu(IV) unstable in simple oxides without stabilizing ligands. Historically, these compounds were named using the terms "cuprous oxide" for Cu₂O and "cupric oxide" for CuO, reflecting the lower and higher valence states of copper, respectively; modern IUPAC nomenclature prefers the systematic names copper(I) oxide and copper(II) oxide to indicate the oxidation state explicitly. These oxides occur naturally as the minerals cuprite (Cu₂O) and tenorite (CuO).^[6]^[7]

Natural occurrence

Copper oxides primarily occur as secondary minerals in the oxidized zones of copper-bearing deposits, formed through supergene weathering processes. Cuprite (Cu₂O) is a notable example, appearing as vibrant red crystals or earthy masses, and serves as a secondary mineral derived from the alteration of primary copper sulfides in near-neutral to slightly alkaline environments.^[8]^[9] Tenorite (CuO), in contrast, manifests as black, sooty coatings or masses and represents a further oxidation product of copper minerals, typically in upper weathering profiles where host rocks exhibit high reactivity and low sulfide content.^[8]^[9] The formation of these oxides involves the oxidative breakdown of copper sulfides, such as chalcopyrite (CuFeS₂), in near-surface geological settings exposed to atmospheric oxygen and meteoric water. This process occurs in the supergene oxidized zones of porphyry copper deposits, involving the direct oxidation of primary copper sulfides by oxygenated meteoric waters. In some cases, secondary sulfides like chalcocite at the base of the oxide zone may further oxidize to cuprite or tenorite under moderate pH conditions.^[9]^[8] Globally, copper oxides are associated with major ore districts, including the Morenci and Ray mines in Arizona, USA; the Chuquicamata, El Abra, and Radomiro Tomic deposits in Chile's Atacama Desert; and the Konkola and Nchanga mines in Zambia's Copperbelt region.^[9] They rarely appear in pure form, instead intergrowing with silicates like chrysocolla, sulfates such as brochantite, or carbonates including malachite, reflecting complex supergene assemblages.^[8]^[10] Trace quantities of copper, occasionally incorporating oxide phases, occur in natural soils derived from weathered copper-rich rocks and are bioaccumulated at low levels in certain marine organisms like phytoplankton, though these are not primary forms of biological concentration.^[11]^[8]

Copper(I) oxide

Physical properties

Copper(I) oxide appears as a red or red-brown crystalline solid, typically in the form of cubic crystals or powder.^[1] Its density is 6.0 g/cm³.^[1] Unlike the black copper(II) oxide, Cu₂O melts at 1232–1235 °C without decomposition and is stable up to about 1000 °C in air before oxidizing further.^[1] It is insoluble in water, with solubility less than 0.001 g/100 mL at 20 °C, but dissolves in mineral acids and ammonia solutions.^[1] Cu₂O exhibits properties of a p-type semiconductor with a direct band gap of approximately 2.0–2.1 eV, allowing absorption of visible light and contributing to its red coloration.^[4]

Chemical properties and structure

Copper(I) oxide (Cu₂O) adopts a cubic crystal structure with space group Pn-3m (cuprite structure), characterized by linear Cu–O–Cu linkages where each Cu⁺ ion is bonded to two O²⁻ ions, and each O²⁻ is tetrahedrally coordinated to four Cu⁺ ions. Lattice parameter a ≈ 4.27 Å.^[12] Cu₂O is diamagnetic due to the d¹⁰ configuration of Cu⁺ ions. It is less thermodynamically stable than CuO at room temperature, with a standard Gibbs free energy of formation ΔG_f° of -146.0 kJ/mol at 298 K. At high temperatures above 1000 °C, it decomposes to copper metal and oxygen:

$2\mathrm{Cu_2O} \rightarrow 4\mathrm{Cu} + \mathrm{O_2}

In moist air, it oxidizes to CuO:

\mathrm{Cu_2O} + \frac{1}{2}\mathrm{O_2} \rightarrow 2\mathrm{CuO}

Cu₂O reacts with acids to form copper(I) salts, though these often disproportionate:

\mathrm{Cu_2O} + 2\mathrm{HCl} \rightarrow 2\mathrm{CuCl} + \mathrm{H_2O}

It dissolves in ammonia to form complexes like [Cu(NH₃)₂]⁺. Cu₂O can be reduced to metallic copper by hydrogen or carbon at elevated temperatures. In redox applications, it acts as a photocatalyst, with its narrow band gap (≈2.1 eV) enabling visible-light-driven reactions such as water splitting or pollutant degradation.^[13]

Production methods

Copper(I) oxide (Cu₂O) is synthesized through controlled oxidation processes that maintain the +1 oxidation state of copper, distinguishing it from full oxidation to CuO. Common methods include thermal oxidation of copper metal at moderate temperatures, reduction of copper(II) compounds, and wet chemical precipitation, often integrated into pigment or semiconductor production. These allow tuning of particle morphology for applications._oxide) Thermal oxidation involves heating copper metal in air or oxygen at 200–300 °C, yielding a red Cu₂O layer via $4\mathrm{Cu} + \mathrm{O_2} \rightarrow 2\mathrm{Cu_2O}. Higher temperatures (>800 °C) favor CuO. This scalable method is used industrially but requires control to avoid over-oxidation.^[14] Reduction of copper(II) precursors is widely used, such as treating copper(II) sulfate with sodium hydroxide and a reducing agent like glucose or hydrazine:

$2\mathrm{CuSO_4} + 2\mathrm{NaOH} + \mathrm{N_2H_4} \rightarrow \mathrm{Cu_2O} + \mathrm{N_2} + 2\mathrm{Na_2SO_4} + 3\mathrm{H_2O}

Thermal decomposition of copper(I) halides or calcination of basic copper carbonate at 200–400 °C also produces Cu₂O. For nanoparticles, hydrothermal methods react copper acetate under 100–200 °C with surfactants, yielding cubic or octahedral nanocrystals.^[15] Industrially, Cu₂O is produced during copper refining by partial roasting of ores or electrolytic processes, achieving >99% purity for pigments and antifouling agents. Green synthesis using plant extracts (e.g., black bean) has emerged for eco-friendly nanoparticle production.^[16]

Applications

Copper(I) oxide (Cu₂O) is used as a red pigment in ceramics, glasses, and paints, providing stable coloration due to its semiconductor properties and resistance to fading.^[1] In marine applications, it serves as an antifouling agent in paints, preventing biofouling on ship hulls by releasing Cu⁺ ions toxic to organisms. As a fungicide, it controls mildew in agriculture and protects wood.^[17] Cu₂O functions as a p-type semiconductor in electronics, including rectifier diodes, solar cells (efficiencies up to 8.4% in transparent cells as of 2021), and photocatalysis for hydrogen production or dye degradation.^[18] In batteries, Cu₂O acts as an anode material in lithium-ion systems, offering high capacity via conversion reactions. Nanoparticles enhance antimicrobial activity against bacteria like E. coli and are explored in gas sensors for NO₂ or H₂S detection at ppm levels. Recent 2025 research highlights Cu₂O nanostructures in supercapacitors (capacitances >500 F/g) and CO₂ reduction catalysts, leveraging tunable band gaps.^[19]

Copper(II) oxide

Physical properties

Copper(II) oxide appears as a black or brown-black solid, typically in the form of an amorphous or microcrystalline powder or granules.^[2] Its density is 6.31 g/cm³ at 300 K.^[20] Unlike the red-colored copper(I) oxide, CuO does not melt but decomposes at approximately 1026 °C into copper(I) oxide and oxygen, remaining stable up to 800 °C in air.^[2] It is insoluble in water, with a solubility of less than 0.001 g/100 mL at room temperature.^[2] CuO exhibits optical properties characteristic of a p-type semiconductor, with a direct band gap ranging from 1.3 to 1.7 eV, enabling absorption of visible light and contributing to its black coloration.^[20] The linear thermal expansion coefficient is 1.8 × 10^{-5} K^{-1}.^[21]

Chemical properties and structure

Copper(II) oxide (CuO) adopts a monoclinic crystal structure with space group C2/c, characterized by lattice parameters of approximately a = 4.68 Å, b = 3.42 Å, c = 5.13 Å, and β = 99.54°.^[22] In this structure, each Cu²⁺ ion is coordinated to four O²⁻ ions in a distorted square planar geometry, forming nearly planar CuO₄ units that are linked into a three-dimensional framework.^[22] CuO exhibits paramagnetism arising from the unpaired d electron in the d⁹ configuration of Cu²⁺ ions. It is thermodynamically more stable than copper(I) oxide (Cu₂O), with a standard Gibbs free energy of formation ΔG_f° of -129.7 kJ/mol at 298 K.^[23] At high temperatures, typically above 800°C, CuO decomposes to Cu₂O and oxygen via the reaction:

$4\text{CuO} \rightarrow 2\text{Cu}_2\text{O} + \text{O}_2

This decomposition is reversible and exploited in thermochemical processes.^[24] CuO displays amphoteric reactivity, dissolving in acids to form copper(II) salts, as in:

\text{CuO} + 2\text{HCl} \rightarrow \text{CuCl}_2 + \text{H}_2\text{O}

and in strong bases under oxidizing conditions to yield copper(II) complexes, such as:

\text{CuO} + 2\text{NaOH} + \text{H}_2\text{O}_2 \rightarrow \text{Na}_2[\text{Cu(OH)}_4]

Additionally, it can be reduced to metallic copper by carbon or hydrogen at elevated temperatures.^[25] In redox applications, CuO serves as an oxidant for desulfurization, reacting with hydrogen sulfide according to:

\text{CuO} + \text{H}_2\text{S} \rightarrow \text{CuS} + \text{H}_2\text{O}

It is also employed as an oxygen carrier in chemical looping combustion, where it cyclically releases and absorbs oxygen to facilitate CO₂ capture during fuel oxidation.^[26] The electronic structure of CuO features a narrow band gap of approximately 1.2–1.8 eV, enabling visible-light absorption and making it suitable for photocatalysis, such as in the degradation of organic pollutants.^[13]

Production methods

Copper(II) oxide (CuO) is primarily synthesized through oxidation processes that fully convert copper to the +2 oxidation state, distinguishing it from partial oxidation routes yielding copper(I) oxide. Common methods include direct thermal oxidation of metallic copper, thermal decomposition of copper salts or hydroxides, and wet chemical precipitation techniques, with industrial production often integrated into copper refining processes. These approaches allow control over particle size and purity, essential for applications in pigments and catalysis.^[27] Thermal oxidation involves heating metallic copper in air or oxygen at temperatures above 800 °C, following the reaction $2\mathrm{[Cu](/page/CU)} + \mathrm{O_2} \rightarrow 2\mathrm{[Cu](/page/CU)O}. This method produces a black, adherent layer of CuO on the copper surface, with the high temperature ensuring complete oxidation beyond the Cu₂O phase stable at lower temperatures (below 300 °C). The process is straightforward and scalable but limited by the need for high-energy input and potential for uneven coating on complex shapes.^[14]^[27] Thermal decomposition of precursors is another key route, particularly calcination of copper(II) nitrate trihydrate at 500–600 °C, which yields CuO via $2\mathrm{Cu(NO_3)_2} \rightarrow 2\mathrm{CuO} + 4\mathrm{NO_2} + \mathrm{O}_2. This exothermic decomposition proceeds through intermediate nitrate loss, producing fine CuO powders with high purity suitable for laboratory use. Similarly, heating copper(II) hydroxide at 80–200 °C decomposes it to CuO and water: \mathrm{Cu(OH)_2} \rightarrow \mathrm{CuO} + \mathrm{H_2O}, a milder process that retains nanostructure from the precursor. These methods are favored for their simplicity and ability to generate uniform particles without additional reducing agents.^[28]^[29]^[30]^[31] Wet chemical methods enable precise control for nanoparticle synthesis. Precipitation typically involves adding sodium hydroxide to copper(II) sulfate solution, forming copper(II) hydroxide precipitate that is filtered, washed, dried, and calcined at 300–500 °C to yield CuO. This approach produces spherical or plate-like nanoparticles with sizes tunable by pH and temperature. Hydrothermal synthesis extends this by reacting copper sulfate under high pressure and temperature (100–200 °C) in an autoclave, often with additives like surfactants, resulting in one-dimensional CuO nanorods or nanoflowers ideal for advanced materials. These techniques are cost-effective and environmentally friendlier than high-temperature methods.^[32]^[33]^[34]^[35] On an industrial scale, CuO is often obtained as a byproduct during copper refining, where copper ores are roasted or leached, followed by precipitation and calcination steps yielding black CuO with purity exceeding 99%. It is also produced specifically for use as a pigment in ceramics and glass, involving controlled oxidation or decomposition to achieve consistent color and dispersibility. These processes integrate CuO production into broader metallurgical flows, minimizing waste and energy use.^[27]^[36]^[37]^[38] Recent advances include sol-gel methods for nanostructured CuO, such as hydrolyzing copper(II) acetate in the presence of urea under controlled pH and temperature (around 80 °C), followed by gelation and calcination at 400–600 °C. This yields porous nanoparticles or thin films with high surface area (up to 100 m²/g), enhancing reactivity for catalysis and sensors. The urea acts as a slow-release base, promoting uniform nucleation and avoiding agglomeration common in precipitation routes.^[39]^[40]^[41]

Applications

Copper(II) oxide (CuO) serves as a key colorant in ceramics, where it reacts with silicates at high temperatures to form blue-green glazes, such as the characteristic "Robin's Egg Blue" achieved through oxidative firing around 850–1000°C.^[42] This color arises from the square planar coordination of Cu²⁺ ions in the glaze matrix, as confirmed by electron paramagnetic resonance spectroscopy.^[42] Additionally, CuO acts as a black pigment in inks and paints due to its fine particle size and light-absorbing properties.^[2] In batteries and electronics, CuO functions as a cathode material in primary lithium batteries, undergoing the reduction reaction CuO + 2Li → Li₂O + Cu, which provides a nominal voltage of about 1.5 V.90099-1) It also serves as a precursor in the synthesis of high-temperature superconductors like yttrium barium copper oxide (YBCO, YBa₂Cu₃O₇), where stoichiometric mixtures of CuO with yttrium and barium compounds are calcined to form the superconducting phase with a critical temperature near 93 K. CuO is widely employed as a catalyst in desulfurization processes, where it absorbs hydrogen sulfide (H₂S) from fuels via the reaction CuO + H₂S → CuS + H₂O, enabling removal of ultra-low concentrations at temperatures as low as 30°C. In hydrogenation reactions, CuO-based catalysts facilitate the reduction of carbonyl compounds and biomass-derived intermediates, often in combination with supports like zirconia to enhance selectivity. For CO oxidation, CuO dispersed on ceria (CeO₂) supports exhibits high activity at low temperatures, converting CO to CO₂ through a Mars-van Krevelen mechanism involving lattice oxygen. Other industrial applications include CuO as a burn rate modifier in double-base rocket propellants, where additions of 1–5 wt% increase combustion rates by promoting catalytic decomposition of the binder.^[43] It also acts as a precursor for synthesizing copper salts like copper sulfate via reaction with acids.^[2] In antimicrobial applications, CuO nanoparticles disrupt bacterial DNA by binding to phosphorus moieties and generating reactive oxygen species, showing high efficacy against Escherichia coli with minimum inhibitory concentrations around 50–100 μg/mL. Emerging post-2020 research highlights CuO in supercapacitors, where nanostructured forms like nanosheets or hybrids with NiO deliver specific capacitances exceeding 1000 F/g at current densities of 1 A/g, attributed to pseudocapacitive redox reactions. For gas sensing, CuO-based sensors detect H₂S or CO at ppm levels (e.g., 1–10 ppm) with responses up to 58,000% for H₂S at room temperature, leveraging p-type semiconducting properties and heterojunctions with materials like In₂O₃.

Health, safety, and environmental impact

Toxicity and handling

Copper oxides, including both copper(I) oxide (Cu₂O) and copper(II) oxide (CuO), are harmful if swallowed or inhaled, with acute oral toxicity in rats showing an LD50 of approximately 470 mg/kg for each compound.^[2]^[1] Ingestion can lead to gastrointestinal distress, including nausea, vomiting, abdominal pain, and symptoms of copper poisoning such as metallic taste and diarrhea.^[44] Inhalation of dust or fumes may cause immediate respiratory irritation, coughing, and headache, potentially progressing to metal fume fever characterized by flu-like symptoms including chills, fever, and muscle aches.^[45] Chronic exposure to copper oxide dusts via inhalation can result in pulmonary inflammation, oxidative stress, and long-term lung damage such as pneumoconiosis-like fibrosis, particularly in occupational settings with repeated low-level exposure.^[46] Skin contact with copper oxides may cause irritation, dermatitis, or allergic reactions upon prolonged exposure, though effects are generally mild compared to respiratory routes.^[47] Copper(II) ions (Cu²⁺) from CuO exhibit higher bioavailability and solubility than copper(I) ions (Cu⁺) from Cu₂O, contributing to increased risks of systemic absorption and neurotoxicity, including potential disruption of cellular redox balance and neuronal damage.^[48] Occupational exposure limits for copper oxides are established based on total copper content, with the National Institute for Occupational Safety and Health (NIOSH) recommending a permissible exposure limit (PEL) of 1 mg/m³ as copper (8-hour time-weighted average) for dusts and mists, and an immediately dangerous to life or health (IDLH) concentration of 100 mg/m³.^[49] Under the Globally Harmonized System (GHS), both Cu₂O and CuO are classified as acutely toxic (H302: harmful if swallowed; H332: harmful if inhaled) and causing serious eye damage (H318).^[1] Safe handling protocols emphasize the use of personal protective equipment (PPE), including nitrile gloves, safety goggles, and NIOSH-approved respirators with particulate filters to minimize skin, eye, and inhalation exposure.^[50] Materials should be stored in tightly sealed containers in a cool, dry, well-ventilated area to prevent dust generation and moisture-induced reactions. For first aid, in cases of ingestion, do not induce vomiting; instead, rinse the mouth and administer 2-4 cups of milk or water if the person is conscious, followed by immediate medical attention. Skin or eye contact requires thorough washing with water for at least 15 minutes, and inhalation exposure warrants fresh air and medical evaluation if symptoms persist. Copper oxide nanoparticles (NPs) pose elevated toxicity risks compared to bulk forms due to enhanced cellular uptake and generation of reactive oxygen species (ROS), leading to oxidative damage and inflammation. Recent studies indicate that CuO NPs are more cytotoxic than Cu₂O NPs in human lung epithelial cells, with greater induction of ROS and cell death at equivalent doses.^[51]

Environmental considerations

Copper oxides, including Cu₂O and CuO, exhibit low solubility in neutral environments but can dissolve under acidic conditions, releasing bioavailable Cu²⁺ ions that persist and bioaccumulate in aquatic ecosystems. This ion release facilitates uptake by organisms, leading to magnification through food chains, particularly in freshwater systems where hardness and pH influence toxicity. Copper concentrations as low as 0.005–0.03 mg/L, depending on water hardness and species, can cause chronic adverse effects in fish, such as impaired reproduction and growth.^[52]^[53]^[54]^[55] In marine settings, Cu₂O used in antifouling paints leaches into coastal waters, contributing to toxicity for non-target species like algae, crustaceans, and shellfish, with environmental concentrations as low as 10 µg/L disrupting benthic communities. This has prompted restrictions in sensitive EU waters since 2008 under the Biocidal Products Regulation, aiming to curb copper emissions from vessel hulls. As of 2025, the EU is reviewing emission limits for copper compounds under REACH to address emerging concerns with nanoparticles.^[56]^[57]^[58]^[59]^[60] On land, CuO nanoparticles from industrial applications persist in soils due to limited degradation, altering microbial diversity and enzyme activity at levels above 50 mg/kg, thereby reducing soil fertility and nutrient cycling.^[58]^[59] Regulatory frameworks address these risks through limits on copper discharges and monitoring requirements. The U.S. EPA establishes an action level of 1.3 mg/L for copper in drinking water to protect public supplies from runoff and industrial sources.^[61] Under EU REACH, both CuO and Cu₂O are classified as H410 (very toxic to aquatic life with long-lasting effects), mandating risk assessments for releases.^[62]^[63] Mitigation strategies focus on reducing emissions and remediating contaminated sites. Recycling copper from spent batteries and ceramics recovers up to 95% of the metal, minimizing mining demands and associated runoff, which remains a primary global source of environmental copper pollution. Alternatives such as zinc-based antifoulants have been adopted in marine applications to lower toxicity while maintaining efficacy. Bioremediation employs copper-tolerant bacteria, like those in the genera Pseudomonas and Bacillus, to immobilize ions through biosorption and precipitation, enhancing soil and water recovery. Climate change exacerbates these issues, as rising temperatures and potential acidification may accelerate copper oxidation and mobility in soils, increasing leaching risks in agricultural and mining areas.^[64]^[65]^[66]

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Acute toxicity. LD50 Oral - Rat - > 2,500 mg/kg. (OECD Test Guideline 423). Inhalation: No data available. LD50 Dermal - Rat - > 2,000 mg/kg. (OECD Test ...
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Copper Oxide Nanoparticles Stimulate the Immune Response and ...
Our results indicate that sub-chronic inhalation of CuO NPs can cause undesired modulation of the immune response.
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Dissolution and Persistence of Copper-Based Nanomaterials in ...
Dec 24, 2015 · Dissolution of copper-based nanoparticles (NPs) can control their environmental persistence and toxicity. Previous research has generally ...
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Review of Copper and Copper Nanoparticle Toxicity in Fish - PMC
Copper is typically found in natural aquatic environments at a low concentration. The analysis of copper toxicity in aquatic organisms is important in aquatic ...
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[PDF] Effects of Copper on Fish and Aquatic Resources
Cu is acutely toxic (lethal) to freshwater fish in soft water at low concentrations ranging from 10 – 20 part per billion (NAS. 1977). Elevated Cu ...
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The use of copper as a biocide in marine antifouling paints
This chapter provides an overview of the current information concerning the concentration and environmental effects of copper in the coastal marine environment.
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Feb 7, 2025 · Copper ions released from antifouling paints are highly toxic to many marine organisms, including algae, molluscs, crustaceans, and fish.
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Antifouling paints leach copper in excess – study of metal release ...
Nov 1, 2020 · In the EU, antifouling products are regulated under the Biocidal Products Regulation (BPR), which states that the recommended dose should be the ...<|separator|>
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Toxicity of copper oxide nanoparticles: a review study - IET Journals
Oct 24, 2019 · This review summarises the in-vitro and in-vivo toxicity of CuO NPs subjected to species (bacterial, algae, fish, rats, human cell lines) used for ...<|separator|>
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Lead and Copper Rule | US EPA
Jan 7, 2025 · In 1991, EPA published a regulation to control lead and copper in drinking water. This regulation is known as the Lead and Copper Rule (also referred to as the ...LCRR Implementation Tools · Drinking Water Lead and... · RevisedMissing: classification oxide aquatic H410 nano- CuO wastewater
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Copper Nanoparticles in Aquatic Environment: Release Routes and ...
Jun 19, 2025 · The aim of this review is to describe the release routes of Cu-based NPs and their adverse effects on fish, while emphasizing the need for further research on ...
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Recycling lithium-ion batteries delivers significant environmental ...
Jan 31, 2025 · Recycling lithium-ion batteries to recover their critical metals has significantly lower environmental impacts than mining virgin metals, ...
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Microbial strategies for copper pollution remediation - PubMed
Apr 1, 2024 · This review article emphasizes on physical, chemical, and biological methods for removal of copper from the wastewater as well asdetailing microorganism's ...
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Estimations of soil metal accumulation or leaching potentials under ...
Jun 6, 2024 · Estimations of soil metal accumulation or leaching potentials under climate change scenarios: the example of copper on a European scale.