Materials

Editorial

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3 pages, 184 KiB

Open AccessEditorial

Measurement of the Environmental Impact of Materials

by Franz-Georg Simon and Ute Kalbe

Materials 2022, 15(6), 2208; https://doi.org/10.3390/ma15062208 - 17 Mar 2022

Cited by 2 | Viewed by 1518

Abstract

Global material use has increased by a factor of eight in the 20th century, and has reached more than 10 tons per capita per year [...] Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

Research

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12 pages, 2422 KiB

Open AccessArticle

Leaching of Titanium Dioxide Nanomaterials from Agricultural Soil Amended with Sewage Sludge Incineration Ash: Comparison of a Pilot Scale Simulation with Standard Laboratory Column Elution Experiments

by Boris Meisterjahn, Nicola Schröder, Jürgen Oischinger, Dieter Hennecke, Karlheinz Weinfurtner and Kerstin Hund-Rinke

Materials 2022, 15(5), 1853; https://doi.org/10.3390/ma15051853 - 1 Mar 2022

Cited by 2 | Viewed by 2135

Abstract

Nanoscale titanium dioxide (nTiO₂ (Hombikat UV 100 WP)) was applied to sewage sludge that was incinerated in a large-scale waste treatment plant. The incineration ash produced was applied to soil as fertilizer at a realistic rate of 5% and investigated in pilot [...] Read more.

Nanoscale titanium dioxide (nTiO₂ (Hombikat UV 100 WP)) was applied to sewage sludge that was incinerated in a large-scale waste treatment plant. The incineration ash produced was applied to soil as fertilizer at a realistic rate of 5% and investigated in pilot plant simulations regarding its leaching behavior for nTiO₂. In parallel, the applied soil material was subject to standard column leaching (DIN 19528) in order to test the suitability of the standard to predict the leaching of nanoscale contaminants from treated soil material. Relative to the reference material (similar composition but without nTiO₂ application before incineration) the test material had a total TiO₂ concentration, increased by a factor of two or 3.8 g/kg, respectively. In contrast, the TiO₂ concentration in the respective leachates of the simulation experiment differed by a factor of around 25 (maximum 91.24 mg), indicating that the added nTiO₂ might be significantly mobilisable. Nanoparticle specific analysis of the leachates (spICP-MS) confirmed this finding. In the standard column elution experiment the released amount of TiO₂ in the percolates between test and reference material differed by a factor of 4 to 6. This was also confirmed for the nTiO₂ concentrations in the percolates. Results demonstrate that the standard column leaching, developed and validated for leaching prediction of dissolved contaminants, might be also capable to indicate increased mobility of nTiO₂ in soil materials. However, experiments with further soils are needed to verify those findings. Full article

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16 pages, 3833 KiB

Open AccessArticle

Long-Term Leaching Behavior of Organic and Inorganic Pollutants after Wet Processing of Solid Waste Materials

by Maria Prieto-Espinoza, Bernd Susset and Peter Grathwohl

Materials 2022, 15(3), 858; https://doi.org/10.3390/ma15030858 - 23 Jan 2022

Cited by 5 | Viewed by 3005

Abstract

The recycling of mineral materials is a sustainable and economical approach for reducing solid waste and saving primary resources. However, their reuse may pose potential risks of groundwater contamination, which may result from the leaching of organic and inorganic substances into water that [...] Read more.

The recycling of mineral materials is a sustainable and economical approach for reducing solid waste and saving primary resources. However, their reuse may pose potential risks of groundwater contamination, which may result from the leaching of organic and inorganic substances into water that percolates the solid waste. In this study, column leaching tests were used to investigate the short- and long-term leaching behavior of “salts”, “metals”, and organic pollutants such as PAHs and herbicides from different grain size fractions of construction & demolition waste (CDW) and railway ballast (RB) after a novel treatment process. Specifically, silt, sand and gravel fractions obtained after a sequential crushing, sieving, and washing process (“wet-processing”) of very heterogeneous input materials are compared with respect to residual contamination, potentially limiting their recycling. Concentrations in solid fractions and aqueous leachate were evaluated according to threshold values for groundwater protection to identify relevant substances and to classify materials obtained for recycling purposes according to limit values. For that, the upcoming German recycling degree was applied for the first time. Very good agreement was observed between short and extensive column tests, demonstrating that concentrations at L/S 2 ratios are suitable for quality control of recycling materials. Different solutes showed a characteristic leaching behavior such as the rapid decrease in “salts”, e.g., SO₄²⁻ and Cl⁻, from all solid fractions, and a slower decrease in metals and PAHs in the sand and silt fractions. Only the gravel fraction, however, showed concentrations of potential pollutants low enough for an unlimited re-use as recycling material in open technical applications. Sand fractions may only be re-used as recycling material in isolated or semi-isolated scenarios. Leaching from heterogeneous input materials proved harder to predict for all compounds. Overall, column leaching tests proved useful for (i) initial characterization of the mineral recycling materials, and (ii) continuous internal (factory control) and external quality control within the upcoming German recycling decree. Results from such studies may be used to optimize the treatment of mixed solid waste since they provide rapid insight in residual pollution of material fractions and their leaching behavior. Full article

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33 pages, 4904 KiB

Open AccessArticle

Mass Transfer Principles in Column Percolation Tests: Initial Conditions and Tailing in Heterogeneous Materials

by Binlong Liu, Michael Finkel and Peter Grathwohl

Materials 2021, 14(16), 4708; https://doi.org/10.3390/ma14164708 - 20 Aug 2021

Cited by 7 | Viewed by 3285

Abstract

Initial conditions (pre-equilibrium or after the first flooding of the column), mass transfer mechanisms and sample composition (heterogeneity) have a strong impact on leaching of less and strongly sorbing compounds in column percolation tests. Mechanistic models as used in this study provide the [...] Read more.

Initial conditions (pre-equilibrium or after the first flooding of the column), mass transfer mechanisms and sample composition (heterogeneity) have a strong impact on leaching of less and strongly sorbing compounds in column percolation tests. Mechanistic models as used in this study provide the necessary insight to understand the complexity of column leaching tests especially when heterogeneous samples are concerned. By means of numerical experiments, we illustrate the initial concentration distribution inside the column after the first flooding and how this impacts leaching concentrations. Steep concentration gradients close to the outlet of the column have to be expected for small distribution coefficients (

K_{d} < 1

L kg⁻¹) and longitudinal dispersion leads to smaller initial concentrations than expected under equilibrium conditions. In order to elucidate the impact of different mass transfer mechanisms, film diffusion across an external aqueous boundary layer (first order kinetics, FD) and intraparticle pore diffusion (IPD) are considered. The results show that IPD results in slow desorption kinetics due to retarded transport within the tortuous intragranular pores. Non-linear sorption has not much of an effect if compared to

K_{d}

values calculated for the appropriate concentration range (e.g., the initial equilibrium concentration). Sample heterogeneity in terms of grain size and different fractions of sorptive particles in the sample have a strong impact on leaching curves. A small fraction (<1%) of strongly sorbing particles (high

K_{d}

) carrying the contaminant may lead to very slow desorption rates (because of less surface area)—especially if mass release is limited by IPD—and thus non-equilibrium. In contrast, mixtures of less sorbing fine material (“labile” contamination with low

K_{d}

), with a small fraction of coarse particles carrying the contaminant leads to leaching close to or at equilibrium showing a step-wise concentration decline in the column effluent. Full article

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15 pages, 7806 KiB

Open AccessArticle

Conversion of Bivalve Shells to Monocalcium and Tricalcium Phosphates: An Approach to Recycle Seafood Wastes

by Somkiat Seesanong, Banjong Boonchom, Kittichai Chaiseeda, Wimonmat Boonmee and Nongnuch Laohavisuti

Materials 2021, 14(16), 4395; https://doi.org/10.3390/ma14164395 - 5 Aug 2021

Cited by 6 | Viewed by 3428

Abstract

The search for sustainable resources remains a subject of global interest and the conversion of the abundantly available bivalve shell wastes to advanced materials is an intriguing method. By grinding, calcium carbonate (CaCO₃) powder was obtained from each shell of bivalves [...] Read more.

The search for sustainable resources remains a subject of global interest and the conversion of the abundantly available bivalve shell wastes to advanced materials is an intriguing method. By grinding, calcium carbonate (CaCO₃) powder was obtained from each shell of bivalves (cockle, mussel, and oyster) as revealed by FTIR and XRD results. Each individual shell powder was reacted with H₃PO₄ and H₂O to prepare Ca(H₂PO₄)₂·H₂O giving an anorthic crystal structure. The calcination of the mixture of each shell powder and its produced Ca(H₂PO₄)₂·H₂O, at 900 °C for 3 h, resulted in rhombohedral crystal β-Ca₃(PO₄)₂ powder. The FTIR and XRD data of the CaCO₃, Ca(H₂PO₄)₂·H₂O, and Ca₃(PO₄)₂ prepared from each shell powder are quite similar, showing no impurities. The thermal behaviors of CaCO₃ and Ca(H₂PO₄)₂·H₂O produced from each shell were slightly different. However, particle sizes and morphologies of the same products obtained from different shells were slightly different—but those are significantly different for the kind of the obtained products. Overall, the products (CaCO₃, Ca(H₂PO₄)₂·H₂O, and Ca₃(PO₄)₂) were obtained from the bivalve shell wastes by a rapidly simple, environmentally benign, and low-cost approach, which shows huge potential in many industries providing both economic and ecological benefits. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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11 pages, 4507 KiB

Open AccessArticle

Evaluation of Hydrogenation Kinetics and Life Cycle Assessment on Mg₂NiH_x–CaO Composites

by Hyo-Won Shin, June-Hyeon Hwang, Eun-A Kim and Tae-Whan Hong

Materials 2021, 14(11), 2848; https://doi.org/10.3390/ma14112848 - 26 May 2021

Cited by 4 | Viewed by 1965

Abstract

Magnesium-based alloys are attractive as hydrogen storage materials due to their lightweight and high absorption, but their high operating temperatures and very slow kinetics are obstacles to practical applications. Therefore, the effect of CaO has improved the hydrogenation kinetics and slowed down the [...] Read more.

Magnesium-based alloys are attractive as hydrogen storage materials due to their lightweight and high absorption, but their high operating temperatures and very slow kinetics are obstacles to practical applications. Therefore, the effect of CaO has improved the hydrogenation kinetics and slowed down the degradation. The Mg₂NiH_x–CaO composites were prepared by hydrogen-induced mechanical alloying (HIMA). Hydrogenation kinetics was performed by using an Automatic PCT Measuring System and evaluated in the temperature range of 423, 523, and 623 K. As a result of calculating the hydrogen absorption amounts through the hydrogenation kinetics curve, they were calculated as about 0.52 wt%, 1.21 wt%, and 1.59 wt% (Mg₂NiH_x–10 wt% CaO). In this study, the material environmental aspects of Mg₂NiH_x–CaO composites were investigated through life cycle assessment (LCA). LCA was performed analyzing the environmental impact characteristics of the manufacturing process by using Gabi software and the Eco-Indicator 99’ and Centrum voor Milieuweten schappen (CML 2001) methodology. As a result, the contents of global warming potential (GWP) and fossil fuels were found to have a higher impact than other impact categories. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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18 pages, 3372 KiB

Open AccessArticle

Effect of Low Zeolite Doses on Plants and Soil Physicochemical Properties

by Alicja Szatanik-Kloc, Justyna Szerement, Agnieszka Adamczuk and Grzegorz Józefaciuk

Materials 2021, 14(10), 2617; https://doi.org/10.3390/ma14102617 - 17 May 2021

Cited by 38 | Viewed by 3190

Abstract

Thousands of tons of zeolitic materials are used yearly as soil conditioners and components of slow-release fertilizers. A positive influence of application of zeolites on plant growth has been frequently observed. Because zeolites have extremely large cation exchange capacity, surface area, porosity and [...] Read more.

Thousands of tons of zeolitic materials are used yearly as soil conditioners and components of slow-release fertilizers. A positive influence of application of zeolites on plant growth has been frequently observed. Because zeolites have extremely large cation exchange capacity, surface area, porosity and water holding capacity, a paradigm has aroused that increasing plant growth is caused by a long-lasting improvement of soil physicochemical properties by zeolites. In the first year of our field experiment performed on a poor soil with zeolite rates from 1 to 8 t/ha and N fertilization, an increase in spring wheat yield was observed. Any effect on soil cation exchange capacity (CEC), surface area (S), pH-dependent surface charge (Qv), mesoporosity, water holding capacity and plant available water (PAW) was noted. This positive effect of zeolite on plants could be due to extra nutrients supplied by the mineral (primarily potassium—1 ton of the studied zeolite contained around 15 kg of exchangeable potassium). In the second year of the experiment (NPK treatment on previously zeolitized soil), the zeolite presence did not impact plant yield. No long-term effect of the zeolite on plants was observed in the third year after soil zeolitization, when, as in the first year, only N fertilization was applied. That there were no significant changes in the above-mentioned physicochemical properties of the field soil after the addition of zeolite was most likely due to high dilution of the mineral in the soil (8 t/ha zeolite is only ~0.35% of the soil mass in the root zone). To determine how much zeolite is needed to improve soil physicochemical properties, much higher zeolite rates than those applied in the field were studied in the laboratory. The latter studies showed that CEC and S increased proportionally to the zeolite percentage in the soil. The Qv of the zeolite was lower than that of the soil, so a decrease in soil variable charge was observed due to zeolite addition. Surprisingly, a slight increase in PAW, even at the largest zeolite dose (from 9.5% for the control soil to 13% for a mixture of 40 g zeolite and 100 g soil), was observed. It resulted from small alterations of the soil macrostructure: although the input of small zeolite pores was seen in pore size distributions, the larger pores responsible for the storage of PAW were almost not affected by the zeolite addition. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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15 pages, 1174 KiB

Open AccessArticle

Determining Adsorption Parameters of Potentially Contaminant-Releasing Materials Using Batch Tests with Differing Liquid-Solid Ratios

by Hirofumi Sakanakura, Kenichi Ito, Jiajie Tang, Mikako Nakagawa and Hiroyuki Ishimori

Materials 2021, 14(10), 2534; https://doi.org/10.3390/ma14102534 - 13 May 2021

Cited by 6 | Viewed by 2229

Abstract

Adsorption parameters such as the distribution coefficient are required to predict the release behavior of contaminants using advection-dispersion models. However, for potentially contaminant-releasing materials (PCMs) such as dredged sludge and coal ash, these parameters cannot be obtained by conventional adsorption tests. This study [...] Read more.

Adsorption parameters such as the distribution coefficient are required to predict the release behavior of contaminants using advection-dispersion models. However, for potentially contaminant-releasing materials (PCMs) such as dredged sludge and coal ash, these parameters cannot be obtained by conventional adsorption tests. This study developed a method to determine adsorption parameters for PCMs from a set of batch tests conducted in parallel as a function of the liquid-solid ratio (LS-parallel test). This LS-parallel test was performed on sandy soil derived from marine sediment using liquid-solid ratios from 1 to 300 L/kg. The water-contact time was also changed from 10 min to 28 d to elucidate the kinetics or equilibrium of contaminants released from the sample. Adsorption parameters were successfully obtained if the substance was under adsorption control. A column percolation test was performed to confirm the effectiveness of the obtained parameters. Good agreements were observed for SO₄²⁻ and B, but discrepancies remained for other substances such as F⁻ and As suggesting that improvements are necessary in both the LS-parallel test procedure and the advection-dispersion model. Full article

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13 pages, 6229 KiB

Open AccessArticle

Environmental Impact of Geosynthetics in Coastal Protection

by Philipp Scholz, Ieva Putna-Nimane, Ieva Barda, Ineta Liepina-Leimane, Evita Strode, Alexandr Kileso, Elena Esiukova, Boris Chubarenko, Ingrida Purina and Franz-Georg Simon

Materials 2021, 14(3), 634; https://doi.org/10.3390/ma14030634 - 29 Jan 2021

Cited by 13 | Viewed by 3606

Abstract

Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly [...] Read more.

Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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14 pages, 2031 KiB

Open AccessArticle

Testing of Eluates from Waterproof Building Materials for Potential Environmental Effects Due to the Behavior of Enchytraeus albidus

by Marya Anne von Wolff and Dietmar Stephan

Materials 2021, 14(2), 294; https://doi.org/10.3390/ma14020294 - 8 Jan 2021

Cited by 2 | Viewed by 2162

Abstract

In order to determine the potential environmental impact of construction products, it is necessary to evaluate their influence on organisms exposed to them or their eluates under environmental conditions. The behavior of the white worm Enchytraeus albidus is a useful tool for assessing [...] Read more.

In order to determine the potential environmental impact of construction products, it is necessary to evaluate their influence on organisms exposed to them or their eluates under environmental conditions. The behavior of the white worm Enchytraeus albidus is a useful tool for assessing the potential environmental impact of construction products in contact with water and soil. This study investigates the environmental effects of eluates from two construction products, a reactive waterproofing product, and an injection resin, on the reproduction and avoidance behavior of E. albidus. The eluates were prepared according to existing guidelines. The soil used for the tests was moistened with the eluates of the construction products. The reproduction results of the worms were collected after six weeks of exposure. Offsprings were counted under the microscope and statistically analyzed. Results from the avoidance behavior were collected after 48 h of exposure, and results were compared with the reproduction results. The eluates from both construction products induced significant changes in the reproduction behavior of E. albidus. Undiluted or only slightly diluted eluates of the injection resin drastically reduced the reproduction of the worms, whereas the leaches of the reactive waterproofing product only had a minor effect. The avoidance results for the injection resin indicates that its presence in the habitat is clearly detrimental to the survival of E. albidus, while the avoidance results for the waterproofing resin showed an initial avoidance of the eluates, but no harmful effects were observed. The avoidance test is a way of rapid toxicity screening of environmental samples when time is a critical parameter to measure possible environmental effects. This study shows that ecotoxicological tests using Enchytraeids are a valuable and important tool for understanding the mode of action of eluates from construction products in the environment. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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16 pages, 20130 KiB

Open AccessEditor’s ChoiceArticle

Formaldehyde Emissions from Wooden Toys: Comparison of Different Measurement Methods and Assessment of Exposure

by Morgane Even, Olaf Wilke, Sabine Kalus, Petra Schultes, Christoph Hutzler and Andreas Luch

Materials 2021, 14(2), 262; https://doi.org/10.3390/ma14020262 - 7 Jan 2021

Cited by 7 | Viewed by 2827

Abstract

Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission [...] Read more.

Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m³ emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r² of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r²: 0.145), thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 µg/m³), especially when more conservative exposure scenarios were considered. Full article

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13 pages, 2365 KiB

Open AccessEditor’s ChoiceArticle

Natural Building Materials for Interior Fitting and Refurbishment—What about Indoor Emissions?

by Matthias Richter, Wolfgang Horn, Elevtheria Juritsch, Andrea Klinge, Leon Radeljic and Oliver Jann

Materials 2021, 14(1), 234; https://doi.org/10.3390/ma14010234 - 5 Jan 2021

Cited by 20 | Viewed by 4247

Abstract

Indoor air quality can be adversely affected by emissions from building materials, consequently having a negative impact on human health and well-being. In this study, more than 30 natural building materials (earth dry boards and plasters, bio-based insulation materials, and boards made of [...] Read more.

Indoor air quality can be adversely affected by emissions from building materials, consequently having a negative impact on human health and well-being. In this study, more than 30 natural building materials (earth dry boards and plasters, bio-based insulation materials, and boards made of wood, flax, reed, straw, etc.) used for interior works were investigated as to their emissions of (semi-)volatile organic compounds ((S)VOC), formaldehyde, and radon. The study focused on the emissions from complete wall build-ups as they can be used for internal partition walls and the internal insulation of external walls. Test chambers were designed, allowing the compounds to release only from the surface of the material facing indoors under testing parameters that were chosen to simulate model room conditions. The emission test results were evaluated using the AgBB evaluation scheme, a procedure for the health-related evaluation of construction products and currently applied for the approval of specific groups of building materials in Germany. Seventeen out of 19 sample build-ups tested in this study would have passed this scheme since they generally proved to be low-emitting and although the combined emissions of multiple materials were tested, 50% of the measurements could be terminated before half of the total testing time. Full article

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27 pages, 5542 KiB

Open AccessArticle

Leaching of Carbon Reinforced Concrete—Part 2: Discussion of Evaluation Concepts and Modelling

by Lia Weiler, Anya Vollpracht and Thomas Matschei

Materials 2020, 13(21), 4937; https://doi.org/10.3390/ma13214937 - 3 Nov 2020

Cited by 4 | Viewed by 2094

Abstract

Possible threats on the environment and human health by the leaching of new building materials and composites in contact to water should be prevented from the outset. It is therefore necessary to assess and ensure their environmental compatibility. For irrigated construction elements this [...] Read more.

Possible threats on the environment and human health by the leaching of new building materials and composites in contact to water should be prevented from the outset. It is therefore necessary to assess and ensure their environmental compatibility. For irrigated construction elements this is a challenging task, as there is no general correlation between known testing methods and outdoor emissions. A feasible assessment concept is needed for these conditions. In this work the German assessment method for permanently wet building materials is applied on different carbon reinforced concrete (C³) leaching data. Furthermore, emission prediction approaches of the Dutch building Materials Decree and the software COMLEAM are tested. The established methods are not yet suitable to determine the complex long term outdoor emissions of irrigated C³. In order to achieve realistic results in time saving testing methods and to define reasonable release limits, it is necessary to determine and verify the relevant influencing parameters on leaching through intermittent water contact. This research works out leaching patterns and correlations between inorganic substances. It is shown that the input parameters time of exposure, contact time, air temperature, air humidity, runoff and background concentration should be considered to predict the leaching processes from irrigated concrete phenomenologically. Full article

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29 pages, 9967 KiB

Open AccessArticle

Leaching of Carbon Reinforced Concrete—Part 1: Experimental Investigations

by Lia Weiler and Anya Vollpracht

Materials 2020, 13(19), 4405; https://doi.org/10.3390/ma13194405 - 2 Oct 2020

Cited by 8 | Viewed by 2507

Abstract

The composite material ‘carbon concrete composite (C³)’ is currently capturing the building sector as an ‘innovative’ and ‘sustainable’ alternative to steel reinforced concrete. In this work, its environmental compatibility was investigated. The focus of this research was the leaching behavior of [...] Read more.

The composite material ‘carbon concrete composite (C³)’ is currently capturing the building sector as an ‘innovative’ and ‘sustainable’ alternative to steel reinforced concrete. In this work, its environmental compatibility was investigated. The focus of this research was the leaching behavior of C³, especially for the application as irrigated façade elements. Laboratory and outdoor exposure tests were run to determine and assess the heavy metal and trace element emissions. In the wake of this work, the validity of laboratory experiments and the transferability to outdoor behavior were investigated. The experimental results show very low releases of environmental harmful substances from carbon concrete composite. Most heavy metal concentrations were in the range of <0.1–8 µg/L, and higher concentrations (up to 32 µg/L) were found for barium, chromium, and copper. Vanadium and zinc concentrations were in the range of 0.1–60 µg/L, boron and nickel concentrations were clearly exceeding 100 µg/L. Most of the high concentrations were found to be a result of the rainfall background concentrations. The material C³ is therefore considered to be environmentally friendly. There is no general correlation between laboratory leaching data and outdoor emissions. The results depend on the examined substance and used method. The prediction and evaluation of the leaching of building elements submitted to rain is therefore challenging. This topic is debated in the second part of this publication. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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22 pages, 2823 KiB

Open AccessReview

Using Environmental Simulations to Test the Release of Hazardous Substances from Polymer-Based Products: Are Realism and Pragmatism Mutually Exclusive Objectives?

by Nicole Bandow, Michael D. Aitken, Anja Geburtig, Ute Kalbe, Christian Piechotta, Ute Schoknecht, Franz-Georg Simon and Ina Stephan

Materials 2020, 13(12), 2709; https://doi.org/10.3390/ma13122709 - 15 Jun 2020

Cited by 12 | Viewed by 2934

Abstract

The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and [...] Read more.

The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented. Full article

(This article belongs to the Special Issue Measurement of the Environmental Impact of Materials)

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