Open Access

Materials‐based gas capture and storage is an increasingly important area of research. Robust and accurate determination of material properties is required for judicial selection of materials for specific applications and for engineering materials–based systems at scale. One key property is the strength of the adsorbate–adsorbent interaction often quantified via the isosteric enthalpy of adsorption. The heat of adsorption can be measured directly through calorimetry; however, a more widely used approach is to apply the Clausius‐Clapeyron (CC) equation to adsorption isotherms collected at different temperatures. While this approach appears to be straightforward, there exist multiple variants in the application of the methodologies employed. This raises the question on how these variations may or may not affect the determined results. Presented here is a discussion of the most common methodologies and a comparison of indirect determinations (via CC) of the isosteric enthalpy of adsorption by different laboratories on identical material. Included in that comparison are discussions on the measurement and analysis reproducibility. Importantly, details of the methodologies are shown to be critical when comparing enthalpies among laboratories, and different methodologies contribute to significant discrepancies and artifacts in the results. Recommendations are provided to promote robust determination and the reporting thereof.

Mechanochemistry offers a solvent-free, sustainable alternative to conventional synthesis of metal-organic framework (MOF) biocomposites, which hold great promise for applications in drug delivery, biocatalysis, and biosensing,[1] yet the field remains limited to batch-type, gram-scale processes that restrict industrial application. To overcome these limitations, we present a scalable solid-state method for producing MOF-based biocomposites via continuous reactive extrusion. The process begins with rapid model reactions using hand-mixing[2] to encapsulate a variety of biomolecules into zeolitic imidazolate framework-8 (ZIF-8), including proteins, carbohydrates, and enzymes, thereby enabling rapid screening and optimization of reaction conditions. The mild synthesis conditions preserve the catalytic activity of glucose oxidase, confirming the suitability of the method to sensitive biomaterials. Building on this, we translated the batch protocol to twin-screw extrusion,[3] enabling continuous and scalable synthesis of biocomposites such as bovine serum albumin (BSA)@ZIF-8 with tunable protein content. The extrusion process yielded highly crystalline, porous materials with protein loadings of up to 26 wt% and encapsulation efficiencies as high as 96%. The production rate reached 1.2 kg d⁻¹, significantly exceeding previously reported continuous methods.[4] To demonstrate the industrial viability of the method, we extended the approach to produce shaped ZIF-8 monoliths loaded with hyaluronic acid (HA) in a single-step extrusion. These monoliths retained their structural integrity during washing and released HA without measurable degradation, as confirmed by size-exclusion chromatography. Our study opens new avenues for the industrial implementation of MOF biocomposites and establishes reactive extrusion as a robust platform for their scalable synthesis and shaping, expanding the toolkit for drug delivery and biocatalytical applications.

Emissions of volatile organic compounds (VOCs) from consumer products may have a negative impact on indoor air quality, potentially also affecting human wellbeing. Since consumers may be exposed to these VOCs immediately after e.g. unwrapping of newly purchased products, reliable analytical methods are needed to determine air concentration profiles in the early phase of VOC emissions. Concerning typical sample sizes of consumer products, micro-scale test chambers (μ-chambers) were considered suitable for this purpose. In addition, compared to medium- or large-scale test chambers, μ-chambers require lower initial investment and operational costs, and offer options for emissions screenings where higher sample throughput is essential. For these reasons, a μ-chamber-based method to determine initial concentrations of VOCs emitting within the first hours of simulated product use was developed. The chamber air was frequently sampled on desorption tubes loaded with Tenax® TA, followed by quantification of emitted VOCs via thermal desorption gas chromatography mass spectrometry (TD-GC-MS). The method was assessed in a round robin test involving eight participating laboratories from 2 countries. Pieces of a rain poncho (sample area A: 2.01·10-4 m2) emitting cyclohexanone, phenol, 2-ethylhexanol, naphthalene and isophorone in significant concentrations were distributed as sample material. Each laboratory conducted triplicate emission tests over a period of 48 h in μ-chambers with volumes of 44 or 114 mL. The loading factors L of 4.57 m2·m-3 (44 mL) or 1.76 m2·m-3 (114 mL) and air flow rates of 24 mL·min-1 resulted in area-specific air flow rates q of 7.17 m3·m-2·h-1 in both chamber types. The temperature was set to 23°C and, if possible, relative humidity was set to approx. 50%. The chamber air was sampled after 0.5, 1, 2, 4, 24 and 48 hours. In addition, to assess the analytical performance, each participating laboratory received two analyte-spiked Tenax® TA-loaded desorption tubes for quality control (QC). Very low relative standard deviations (11–17%) were obtained for the QC test. The results of the emissions tests in the early phase (0.5–4 h) were also adequate, with acceptable z scores (|z|≤2.00) received by six to seven participating laboratories. All eight laboratories obtained acceptable z scores after the longer sampling periods (24 and 48 h). Hence, the inter-laboratory comparability of the results obtained with the developed μ-chamber method was successfully confirmed.

The construction sector is one of the most resource-intensive sectors in Germany and is responsible for 40 % of CO2 emissions. emissions. Around 517 million tons of mineral raw materials are required annually for the construction of buildings in Germany. At the same time, mineral construction waste was the largest material flow at 229.3 million tons (2020). The rates of building material recycling have increased since 2000, especially for mineral waste. Nevertheless, the majority of recycled aggregates are used in technically largely unregulated applications (e.g. road construction). This downcycling leads to a loss of valuable resources for technically and economically valuable uses. The upMIN100 research project is investigating the question of whether and to what extent recycled mineral construction and demolition waste is suitable as an additive in earthen building materials such as earth plasters and earth blocks. The focus is placed on grain sizes < 2 mm, which are currently predominantly landfilled, as there are currently no regulations for their use in building products. In order to enable the use of construction and demolition waste, the technical feasibility must be ensured, quality requirements for source materials (e.g. limit values for pollutants in terms of health and environmental environmental compatibility and hazardous substances) and permissible proportions of recycled aggregates must be defined. To avoid negative impact on building occupants, the developed building materials have been tested in terms of harmful substances included in the mineral waste as well as emissions into the ambient air. Furthermore, the earthen building products, manufactured from mineral waste, should be free from pollutants to enable a return into the environment. According to the Substitute Building Materials Ordinance (EBV) this corresponds to criterion BM-0. Two different building material developments were used to test the technical feasibility and the pollutant content of the recycled aggregate.

Im Rahmen der von der BAM und anderen Partnern ins Leben gerufenen Initiative „Digitale Qualitätsinfrastruktur“ liegt der Fokus u.a. auf der Entwicklung von neuen Zertifizierungsworkflows. Dabei ist eine besondere Bedeutung dem Zusammenführen von Operational Technology (OT) und Informationstechnik (IT) beizumessen. Zur Datenintegration aus der Sensor-Feldebene einer Versuchs-Wasserstofftankstelle wurde eine solche Infrastruktur aufgebaut. Zudem wurde der von der Plattform Industrie 4.0 empfohlene standardisierte Zwilling „Verwaltungsschale“ für einige Assets der Wasserstofftankstelle implementiert.