Field data on plastic pollution is extremely limited in Southeast Asian rivers. Here we present the first field measurements of plastic transport in the Mekong, based on a comprehensive monitoring campaign during the monsoon season in the confluence of the Mekong, Tonle Sap, and Bassac rivers around Cambodia’s capital (Phnom Penh). For improved accuracy in the estimation of plastic loads and distribution, we combined Neuston net multipoint cross-sectional water sampling with acoustic Doppler current profiler high resolution measurements. During the wet season, around 2.03 × 105 kg d−1 of plastic were released from Phnom Penh into the Mekong, equivalent to 89 g d−1 capita−1, or 42% of all plastic waste generated in the city. Most plastic mass moved downstream at the surface. A smaller portion of plastics is mixed deep into the water column, potentially retained in the rivers, breaking down and resuspending over time. Overall, plastic waste from Phnom Penh and transported by the Mekong is a significant contribution to Southeast Asia’s plastic release into the ocean. This pollution represents a crucial risk to people in the region, as their livelihoods depend on fisheries from these water bodies.
Metal deterioration via corrosion is a ubiquitous and persistent problem. Ångström-scale, atomically thin 2D materials are promising candidates for effective, robust, and economical corrosion passivation coatings due to their ultimate thinness and excellent mechanical and electrical properties. This review focuses on elucidating the mechanism of 2D materials in corrosion mitigation and passivation related to their physicochemical properties and variations, such as defects, out-of-plane deformations, interfacial states, temporal and thickness variations, etc. In addition, this review discusses recent progress and developments of 2D material coatings for corrosion mitigation and passivation as well as the significant challenges to overcome in the future.
Goldbeating is the ancient craft of thinning bulk gold (Au) into gossamer leaves. Pioneered by ancient Egyptian craftsmen, modern mechanized iterations of this technique can fabricate sheets as thin as ∼100 nm. We take inspiration from this millennia-old craft and adapt it to the nanoscale regime, using colloidally synthesized 0D/1D Au nanoparticles (AuNPs) as highly ductile and malleable nanoscopic Au ingots and subjecting them to solid-state, uniaxial compression. The applied stress induces anisotropic morphological transformation of AuNPs into 2D leaf form and elucidates insights into metal nanocrystal deformation at the extreme length scales. The induced 2D morphology is found to be dependent on the precursor 0D/1D NP morphology, size (0D nanosphere diameter and 1D nanorod diameter and length), and their on-substrate arrangement (e.g., interparticle separation and packing order) prior to compression. Overall, this versatile and generalizable solid-state compression technique enables new pathways to synthesize and investigate the anisotropic morphological transformation of arbitrary NPs and their resultant emergent phenomena.