Abstract
Inorganic–organic hybrid nanoporous materials (NPMs), such as amorphous mesoporous aluminosilicates and Metal-Organic Frameworks (MOFs) are designed and developed for numerous application fields including health care, industrial cooling systems, air purification and gas storage. Their usage and production is expected to increase significantly within the next years, with new applications such carbon capture and storage becoming increasingly important.
In this study, we investigate the environmental behaviour of 6 NPMs and determine their toxicity towards the freshwater algae Raphidocelis subcapitata. The size, surface charge density and dispersion stability of UiO-66-COOH, Al(OH)-fumarate, HKUST, Zn-CPO, FeBTC-JM-AR and CPO-27-Ni are investigated in relevant environmental test media. Furthermore, we study the dissolution of metals and other elements from NPMs in test media, and their contribution to the observed effects on R. subcapitata.
Particle size measurements showed that the NPMs have a primary particle size between 200 nm and several micrometres. In freshly sonicated stock dispersions, the measured z-averages ranged from 600 nm (CPO-27-Ni) up to 8 µm (HKUST). ZnCPO and CPO-27-Ni had the most negative zeta-potential of -25 and -20 mV respectively, with Al (OH) fumarate and FeBTC-JM-AR featuring a positive surface charge. UiO-66-COOH and HKUST had very weak surface potentials, which was also reflected in their instability in the stock and exposure media.
In a first dissolution study, 5 out of 6 materials (100 mg/L) caused an increase in specific dissolved metals or elements in the exposure media, both directly after dispersion preparation and after a 72 h incubation period, reflecting the duration of an R. subcapitata standard toxicity test. Most notable releases after 72 h were from Zn-CPO (Zn, 3457 µg/L), CPO-27-Ni (Ni, 235 µg/L) and HKUST (Cu, 143 µg/L). UiO-66-COOH caused a 100 % increase in S in the exposure media, while Al(OH)-fumarate caused an increase of Al from 11 mg/L to around 60 mg/L. FeBTC-JM-AR was the most inert material regarding release of dissolved metals. Due to their adsorption properties, the materials also drastically reduced amount of P in the exposure media, with UiO-66-COOH also decreasing Ca and Mn. Potential mode-of actions, i.e. impact of NPM particles through depletion of nutrient elements, toxicity of dissolved metals, or effects from organic components will be identified in the R. subcapitata toxicity tests.
In this study, we investigate the environmental behaviour of 6 NPMs and determine their toxicity towards the freshwater algae Raphidocelis subcapitata. The size, surface charge density and dispersion stability of UiO-66-COOH, Al(OH)-fumarate, HKUST, Zn-CPO, FeBTC-JM-AR and CPO-27-Ni are investigated in relevant environmental test media. Furthermore, we study the dissolution of metals and other elements from NPMs in test media, and their contribution to the observed effects on R. subcapitata.
Particle size measurements showed that the NPMs have a primary particle size between 200 nm and several micrometres. In freshly sonicated stock dispersions, the measured z-averages ranged from 600 nm (CPO-27-Ni) up to 8 µm (HKUST). ZnCPO and CPO-27-Ni had the most negative zeta-potential of -25 and -20 mV respectively, with Al (OH) fumarate and FeBTC-JM-AR featuring a positive surface charge. UiO-66-COOH and HKUST had very weak surface potentials, which was also reflected in their instability in the stock and exposure media.
In a first dissolution study, 5 out of 6 materials (100 mg/L) caused an increase in specific dissolved metals or elements in the exposure media, both directly after dispersion preparation and after a 72 h incubation period, reflecting the duration of an R. subcapitata standard toxicity test. Most notable releases after 72 h were from Zn-CPO (Zn, 3457 µg/L), CPO-27-Ni (Ni, 235 µg/L) and HKUST (Cu, 143 µg/L). UiO-66-COOH caused a 100 % increase in S in the exposure media, while Al(OH)-fumarate caused an increase of Al from 11 mg/L to around 60 mg/L. FeBTC-JM-AR was the most inert material regarding release of dissolved metals. Due to their adsorption properties, the materials also drastically reduced amount of P in the exposure media, with UiO-66-COOH also decreasing Ca and Mn. Potential mode-of actions, i.e. impact of NPM particles through depletion of nutrient elements, toxicity of dissolved metals, or effects from organic components will be identified in the R. subcapitata toxicity tests.