eNPs-EUG

Nanofertilizers comprising engineered nanoparticles (ENPs) have great potential in sustainable agriculture due to their strong capabilities of improving crop yields. As an effective fertilization strategy, foliar spraying could lead to broken and splashed ENP droplets, resulting in inaccurate leaf targeting and potential environmental contamination. Herein, we propose embedding Fe-based ENPs into a supramolecular hydrogel to effectively enhance the deposition amount on leaves and thus the bioavailability. The proper rheological properties of the hydrogel droplets and their robust interaction with soybean leaf simultaneously reduce the droplet rebound and fragmentation, especially under elevated impact speeds, resulting in up to 168.9% more droplet deposition compared to the ENP suspension. Computational fluid dynamics simulation analysis suggests that the contact angle is a key sensitive factor influencing the dynamic deposition behavior of the hydrogel droplet. A 15% reduction in the contact angle results in a 14% reduction of the highest bouncing height. The incorporation of ENPs enhances the viscous dissipation rate by 7.4% in comparison with pure hydrogel droplets. The hydrogel embedding also causes a 1.5-fold increase in ENP uptake compared to that of the ENP suspension. The hydrogel embedding delivers a reduction of 80% in the ENP application amount, compared to ENP suspensions, while achieving a 28% increase in the fresh weight of soybean seedlings. This work provides an effective method to enhance the deposition of ENPs during foliar application.

With an increasing production and use of engineered nanoparticles (ENPs), inevitably grows their release into the environment. This makes it important to determine in what quantitates they occur in aquatic systems like seawater. However, even when using the most sensitive ICP-MS technique, quantification of very low seawater concentrations of ENPs is still concept rather than the fact. To approach this goal, a unified protocol for the preparation of seawater samples for ICP-MS analysis has been developed in this study using a selection of silver, titanium dioxide and zinc oxide nanoparticles. In order to minimize the risk of particle loss, the effect of sample pH was examined and it was found out that a moderate in-field acidification (to pH 7.5) ensures particle stability prior to analysis. Ultrafiltration through commercial 3 kDa membrane filters was shown feasible to separate the ENPs from the bulk seawater sample provided that the filter unit is pre-conditioned with 0.1 M copper nitrate to avoid ionic metal adsorption. The following ultrasound-mediated dissolution in 30% HNO₃ directly in the filer unit and ultrafiltration makes the metals constituting the ENPs amenable to analysis. The latter was for the first time performed using high-resolution ICP-MS method validated according to the common EU standards. The limits of detection attained here were as low as 0.06, 0.09, and 17.5 μg L^-1 for Ag, TiO₂, and ZnO nanoparticles, respectively. Accuracy of the method was tested with uncontaminated open-sea water spiked with ENPs and recoveries were acceptable ranging from 85 to 110%.