Rivers play a major role in the transport of plastic debris from inland sources such as urban areas into the marine environment. The present study examined plastic particle concentrations and loads (>500 μm) upstream and downstream of an urban subcatchment over 15 months and investigated the relationship between river water discharge (Q) and plastic concentration (C). The plastic particle concentration increases by 0.8 g/1000 m3 or 79 n/1000m3 from the rural to the urban subcatchment. In the rural subcatchment, C does not increase with increasing Q (p = 0.57), whereas a positive relationship between C and Q exists downstream of the urban catchment (p = 0.00003). Combined sewer overflows likely contribute additional plastic loads during high flow conditions. Based on the C–Q relationship, we estimate the total plastic export in 2016 from the entire catchment to be 3.0 × 106 n/year or 2.6 × 104 n/(km2 year) and 15 n/(cap year). Because of the positive C–Q relationship, 90% of the plastic load is transported during 20% of the time. The analysis of time-resolved plastic concentration data in rivers provides a data-driven tool to better estimate plastic loads and to better understand the catchment controls of plastic in rivers.

Three-dimensional, highly interconnected copper nanowire networks are designed and fabricated by electrodeposition in etched ion track polymer templates with interconnected nanochannels and subsequently applied as a catalyst for the electrochemical CO 2 reduction toward hydrocarbons and alcohols in an aqueous electrolyte. The specific surface area expressed by the nanowire networks can be adjusted by tailoring the wire length, wire diameter, and nanowire number density to values between 70 cm 2 and 300 cm 2 per cm 2 geometrical sample area. The conversion efficiency and selectivity of CO 2 reduction toward liquid-and gas-phase products are studied as a function of the applied potential. Before and after the CO 2 reduction reaction, the nanowire networks are characterized by scanning and transmission electron microscopy and by X-ray diffraction, evidencing their stability during CO 2 reduction in a potential region between −0.5 V and −0.93 V versus RHE.

In this work, mild Lewis acids and low environmental impact solvents were investigated for Nenitzescu synthesis. Cyclopentyl methyl ether can be used at room temperature in substitution of halogenated solvents with zinc, iron and magnesium salts as homogeneous catalysts to give 5-hydroxyindoles in fair to good yields. The reaction features a straightforward workup and excellent solvent recycle.