Multi-walled Carbon Nanotubes, NM-400, NM-401, NM-402, NM-403: Characterisation and Physico-Chemical Properties

In 2011 the JRC launched a Repository for Representative Test Materials that supports both EU and international research projects, and especially the OECD Working Party on Manufactured Nanomaterials' (WPMN) exploratory testing programme "Testing a Representative set of Manufactured Nanomaterials" for the development and collection of data on characterisation, toxicological and ecotoxicological properties, as well as risk assessment and safety evaluation of nanomaterials. The JRC Repository responds to a need for availability of nanomaterial from a single production batch to enhance the comparability of results between different research laboratories and projects. The present report presents the physico-chemical characterisation of the multi-walled carbon nanotubes (MWCNT) from the JRC Repository: NM-400, NM-401, NM-402 and NM-403. NM-400 was selected as principal material for the OECD WPMN testing programme. They are produced by catalytic chemical vapour deposition. Each of these NMs originates from one respective batch of commercially manufactured MWCNT. They are nanostructured, i.e. they consist of more than one graphene layer stacked on each other and rolled together as concentric tubes. The MWCNT NMs may be used as a representative material in the measurement and testing with regard to hazard identification, risk and exposure assessment studies. The results are based on studies by several European laboratories participating to the NANOGENOTOX Joint Action.JRC.I.4-Nanobioscience

Titanium Dioxide, NM-100, NM-101, NM-102, NM-103, NM-104, NM-105: Characterisation and Physico-Chemical Properties

The European Commission's Joint Research Centre (JRC) provides scientific support to European Union policy including nanotechnology. Within this context, the JRC launched, in February 2011, a repository for Representative Test Materials (RTMs), based on preparatory work started in 2008. It supports both EU and international research projects, and especially the OECD Working Party on Manufactured Nanomaterials (WPMN). The WPMN leads an exploratory testing programme "Testing a Representative set of Manufactured Nanomaterials" for the development and collection of data on characterisation, toxicological and ecotoxicological properties, as well as risk assessment and safety evaluation of nanomaterials. The purpose is to understand the applicability of the OECD Test Guidelines for the testing of nanomaterials as well as end-points relevant for such materials. The Repository responds to a need for nanosafety research purposes: availability of nanomaterial from a single production batch to enhance the comparability of results between different research laboratories and projects. The availability of representative nanomaterials to the international scientific community furthermore enhances and enables development of safe materials and products. The present report presents the physico-chemical characterisation of the Titanium dioxide series from the JRC repository: NM-100, NM-101, NM-102, NM-103, NM-104 and NM-105. NM-105 was selected as principal material for the OECD test programme "Testing a representative set of manufactured nanomaterials". NM-100 is included in the series as a bulk comparator. Each of these NMs originates from one batch of commercially manufactured TiO2. The TiO2 NMs may be used as representative material in the measurement and testing with regard to hazard identification, risk and exposure assessment studies. The results for more than 15 endpoints are addressed in the present report, including physico-chemical properties, such as size and size distribution, crystallite size and electron microscopy images. Sample and test item preparation procedures are addressed. The results are based on studies by several European laboratories participating to the NANOGENOTOX Joint Action, as well as by the JRC.JRC.I.4-Nanobioscience

Powder XRD Study of Changes of Cd2+ Modified Clinoptilolite at Different Stages of the Ion Exchange Process

Cadmium exchange on clinoptilolite is performed and structurally studied for different durations of the ion exchange process (2 h, 24 h, 72 h, 168 h, 12 days, 22 days) at room temperature and 90 °C. The distribution of Cd2+ ions in all samples is elucidated after exchange on clinoptilolite using powder XRD data processed by Rietveld structural software. Clinoptilolite is not selective for cadmium cations, but at 90 °C the exchange is ~2.5 cations per unit cell. At RT it reaches ~1.25 cations per unit cell being twice as low. The obtained maximum exchanged sample for 22 days 90 °C was structurally refined in order to find the cadmium positions in the clinoptilolite voids. The structural refinements of the occupations of the incoming and outgoing cations give an idea of how the intracrystalline diffusion is processed. A good correlation between results obtained by structural refinement of the Cd-exchanged samples and the data of the EDS measurements was achieved

Structural Features and Thermal Behavior of Ion-Exchanged Clinoptilolite from Beli Plast Deposit (Bulgaria)

The structural features and the thermal behavior of natural, Na-, Ca-, K-, Mg-, and Cd-exchanged clinoptilolite from the Beli Plast deposit (Bulgaria) were studied. Purified clinoptilolite sample was preliminary prepared and ion-exchanged at 100 °C for six days. DSC-TG analyses were performed for all studied forms. The effects in the DSC curves show differences with temperature due to release of weakly bound H2O molecules and strongly bound ones. The endotherm minima temperatures were between 78 and 115 °C decreasing in the sequence K- 2O molecules and the non-coordinating ones were determined by XRD structural refinement for all exchanged samples. The H2O molecules of the cation–hydrate complexes are released at higher temperatures than weakly bound ones and affected the DSC curves differently. The structural adjustments made by the Rietveld method, as well as the applied EDS analyzes for the chemical composition of the samples, allowed us to correlate these data to the thermal characteristics of the studied clinoptilolite samples