I. Odnevall Wallinder

A laboratory study of copper and zinc runoff during first flush and steady-state conditions

The influence of environmental conditions and corrosion layer characteristics have been investigated on the runoff rate of copper and zinc, used as roofing material. For this purpose, a rain device ...

Seasonal variations in corrosion rate and runoff rate of copper roofs in an urban and a rural atmospheric environment

This paper summarizes the results from an extensive field exposure program implemented to study possible seasonal dependencies of copper corrosion rates and runoff rates. Two-year exposures in one ...

Surface-protein interactions on different stainless steel grades: effects of protein adsorption, surface changes and metal release

Implantation using stainless steels (SS) is an example where an understanding of protein-induced metal release from SS is important when assessing potential toxicological risks. Here, the protein-induced metal release was investigated for austenitic (AISI 304, 310, and 316L), ferritic (AISI 430), and duplex (AISI 2205) grades in a phosphate buffered saline (PBS, pH 7.4) solution containing either bovine serum albumin (BSA) or lysozyme (LSZ). The results show that both BSA and LSZ induce a significant enrichment of chromium in the surface oxide of all stainless steel grades. Both proteins induced an enhanced extent of released iron, chromium, nickel and manganese, very significant in the case of BSA (up to 40-fold increase), whereas both proteins reduced the corrosion resistance of SS, with the reverse situation for iron metal (reduced corrosion rates and reduced metal release in the presence of proteins). A full monolayer coverage is necessary to induce the effects observed.

Hemolytic properties of synthetic nano- and porous silica particles: The effect of surface properties and the protection by the plasma corona

Novel silica materials incorporating nanotechnology are promising materials for biomedical applications, but their novel properties may also bring unforeseen behavior in biological systems. Micro-size silica is well documented to induce hemolysis, but little is known about the hemolytic activities of nanostructured silica materials. In this study, the hemolytic properties of synthetic amorphous silica nanoparticles with primary sizes of 7-14 nm (hydrophilic vs. hydrophobic), 5-15 nm, 20 nm and 50 nm, and model meso/macroporous silica particles with pore diameters of 40 nm and 170 nm are investigated. A crystalline silica sample (0.5-10 μm) is included for benchmarking purposes. Special emphasis is given to investigations of how the temperature and solution complexity (solvent, plasma), as well as the physicochemical properties (such as size, surface charge, hydrophobicity and other surface properties), link to the hemolytic activities of these particles. Results suggests the potential importance of small size and large external surface area, as well as surface charge/structure, in the hemolysis of silica particles. Furthermore, a significant correlation is observed between the hemolytic profile of red blood cells and the cytotoxicity profile of human promyelocytic leukemia cells (HL-60) induced by nano- and porous silica particles, suggesting a potential universal mechanism of action. Importantly, the results generated suggest that the protective effect of plasma towards silica nanoparticle-induced hemolysis as well as cytotoxicity is primarily due to the protein/lipid layer shielding the silica particle surface. These results will assist the rational design of hemocompatible silica particles for biomedical applications.

A study of copper runoff in an urban atmosphere

Abstract Initiated by the concern in several countries regarding the release of copper from, e.g., roofs, facings and other outdoor constructions, the present study aims to compare runoff rates with corrosion rates during exposure of copper in an urban atmosphere. The copper runoff rate turns out to be relatively stable during the 2 year period studied, with an average rate per year of around 135 μg Cu cm −2 . This stable runoff rate is associated with the formation and dissolution properties of cuprite (Cu 2 O), which is the dominating copper patina phase throughout the 2 year period. The copper corrosion rate, on the other hand, is highly time-dependent. It exhibits an initially high value and decreases with exposure time. As a consequence, the ratio between copper runoff and copper mass loss is very low in the beginning, around 7% after 1 month, and increases with time to reach around 22% after 2 years. With prolonged exposure this ratio eventually reaches 100%, corresponding to a copper patina thickness that does not change any further with time.

Runoff rates and ecotoxicity of zinc induced by atmospheric corrosion.

Initiated by regulatory restrictions on the use of zinc for various building and construction applications, together with a lack of knowledge related to the release of zinc induced by atmospheric corrosion, a major interdisciplinary research project was implemented to generate data to be used in future risk assessment. Runoff rates from a large number of commercially available zinc-based materials have been determined on panels inclined 45 degrees from the horizon, facing south, during a 1-year atmospheric exposure in an urban environment in Sweden. Possible environmental effects of runoff water immediately after leaving the surface of the various materials have been evaluated during two different sampling periods of varying season and zinc concentration, using the standard growth inhibition test with algae. Raphidocelis subcapitata (formerly Selenastrum capricornutum). Zinc-specific biosensors with the bacterial strain of Alcaligenes eutrophus, and computer modeling using the water-ligand model MINTEQA2 and the humic aquatic model WHAM, have been used to assess the bioavailability and chemical speciation of zinc in the runoff water. An excellent consistency between the different methods was observed. The results show considerably lower runoff rates of zinc (0.07-3.5 g m(-2) year(-1)) than previously being used for regulatory restrictions, and the concentration of zinc to be predominantly responsible for the observed toxicity of the runoff water towards the green algae. The majority of the released zinc quantity was found to be present as free hydrated zinc ions and, hence, bioavailable. The data do not consider changes in bioavailability and chemical speciation or dilution effects during entry into the environment, and should therefore only be used as an initial assessment of the potential environmental effect of zinc runoff from building applications. This interdisciplinary approach has the potential for studies on the environmental fate of zinc in soil or aquatic systems.

A Comparison of Release Rates of Cr, Ni, and Fe from Stainless Steel Alloys and the Pure Metals Exposed to Simulated Rain Events

With increasing environmental awareness, the desire to protect human beings and the environment from adverse effects induced by dispersed metals has become an issue of great concern and interest. New policies, such as REACH (Registration, Evaluation, Authorisation and Restriction of Chemicals) within the European Community, have been implemented to reduce hazards posed by the use of chemicals on producers and downstream users. The generation of exposure assessment data and relevant test procedures able to simulate realistic scenarios are essential in such legislative actions. This doctoral study was initiated to fill knowledge gaps related to the metal release process of stainless steels. A wide range of stainless steel grades, fourteen in total, were investigated. They cover a very broad range of applications, and the focus in the thesis was to simulate a few selected exposure scenarios: precipitation, the human body and food intake. Comparisons were made between metal release from stainless steel alloys and the pure metals that constitute each stainless steel in order to explore the differences between alloys and pure metals, and to provide quantitative data on metal release rates of different alloy constituents. Because of similar surface properties between stainless steel and pure chromium, this metal exhibits similar release rates, whereas iron and nickel exhibit significantly lower release rates as alloy components than as pure metals. Detailed studies were also performed to elucidate possible relations between metal release and steel surface properties. Key parameters turned out to be chromium enrichment of the self-passivating surface film, surface roughness, the electrochemically active surface area and the microstructure of the steel substrate. The degree of metal release increased with decreasing chromium content in the surface oxide, increasing surface roughness, and increasing presence of inhomogeneities in the bulk matrix. More detailed studies were initiated to possibly correlate the nucleation of metastable pits and the extent of metal release. Evidence was given that metastable pits exist even when the stainless steel is passive, and may cause extremely short-lived bursts of released metal before the surface film repassivates again.

Atmospheric corrosion of zinc-based materials: runoff rates, chemical speciation and ecotoxicity effects

In order to fill some major gaps of knowledge for future risk assessments, an interdisciplinary research effort is going on in order to generate relevant zinc runoff rate data from various commercial zinc-based materials, and to explore the relation between the chemical speciation of zinc in runoff water and its ecotoxicity. This study presents runoff rates, based on 1-year exposures of 15 zinc-based materials, which range from 0.07 to 3.5 g/m2 year. When collected immediately after release from the various zinc-based surfaces, chemical speciation modeling of the runoff water suggests that nearly all zinc (>95%) is present as hydrated Zn2+ ions, the most bioavailable speciation form. Evaluation of zinc runoff for possible environmental effects was performed through growth inhibition test with a green alga, Raphidocelis subcapitata. The results show a high correlation between the amount of zinc in the runoff and the environmental effect, suggesting, again, that all zinc is present as hydrated Zn2+. The insight gained aids in predicting actual ecotoxicity effects during environmental fate of zinc, based on chemical speciation of zinc in the runoff.

A Comparison Between Corrosion Rates and Runoff Rates from New and Aged Copper and Zinc as Roofing Material

Recently there has been anincreased environmental concern in severalcountries in Europe, in particular in Sweden andin the Netherlands regarding the amount of copperand zinc that is released from building materialsinto society. Due to lack of runoff data, thelegislators have so far used corrosion ratesmeasured during the last 20 years to calculatequantities of metal released from buildingsassuming that the quantity of metal corrosionequals the quantity of metal runoff. Withdecreasing levels of environmental pollutantsduring the last decade in Europe, it is importantto determine more recent and hence morerepresentative corrosion and runoff rates to beused in the calculations. For this reason a field exposure program was implemented during 48 weeks in an urbanatmosphere in Sweden determining corrosion andrunoff rates for copper and zinc of differentage. New copper exposed for 48 weeks in the urbanatmosphere shows a corrosion rate of 6.7gm-2y-1 and an almost constant runoff rate of1.3 gm-2y-1 during the period. Therunoff rate is significantly lower than thecorrosion rate and represents only a fraction(≤20%) of the total amount of corroded metalduring this period. Zinc shows a graduallydecreasing corrosion rate with time being 5.0gm-2y-1 after 48 weeks of exposure. Therunoff rate is relatively stable with an averagerate of 3.1 gm-2y-1 during the sameperiod. This value represents ≈60% of the totalamount of corroded zinc. The effect of panel age has been investigatedin parallel field and laboratory studies. Theresults show that naturally aged copper exhibitssomewhat higher average runoff rates (2 gm-2y-1) than new copper, probably due to acombined effect of storage and weatherconditions. No significant difference in runoffrate can be found between new and naturally agedzinc. The field and laboratory investigationsshow that precipitation rate and amount influence the magnitude of the runoff rate forboth copper and zinc.

Multianalytical in situ investigation of the initial atmospheric corrosion of bronze

Atomic force microscopy (AFM) and infrared reflection absorption spectroscopy (IRAS) were used for in situ investigations of the initial atmospheric corrosion of bronze. In addition ex situ XPS inv ...