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Essential properties for a Point of Use (POU) water filter include maintaining high removal capacity and rate, with excellent mechanical properties to withstand pressure drop. Herein, mechanically robust tri-composite polyamide 6/iron oxide nanoparticles/tetra-n-butylammonium bromide (PA6/α-Fe[sub 2]O[sub 3]/TBAB) nanofiber composite membranes were electrospun for phosphate (P) remediation, where the diameter and composition were tuned by controlling solution compositions and electrospinning conditions. Tri-composite composition and morphology affect phosphate uptake where the adsorption capacity followed Langmuir isotherm whereas the adsorption kinetics followed pseudo second order behavior. Mechanical properties (i.e., Young's Modulus (E) and toughness) were significantly influenced by the composition and morphology of the tricomposite, as well. Although additional TBAB and iron oxide decreased toughness, there are optimum composition ranges which resulted in maximum Young's Modulus. Of the synthesized nanofiber membranes, PA6/α-Fe2O3/TBAB nanofibers with 17% α-Fe2O3 and 2% TBAB showed excellent phosphate uptake capacity [i.e., 8.9 mg/g (52 mg of P/g of α-Fe2O3)] while it is bendable, stretchable, and able to plastically deform without fracturing (i.e., Young's modulus of 2.06 x 108 Pa and Toughness of 1.35 x 106 J m-3). With concerns over the impact of P on water resources and the long-term availability of limited P resources, this tri-composite membrane is well suited for applications in both wastewater treatment and resource recovery. [ABSTRACT FROM AUTHOR]

Environmental transformation processes, including those occurring in natural and engineered systems, do not necessarily drastically alter molecular structures of bioactive organic contaminants. While the majority of generated transformation products are likely benign, substantial conservation of structure in transformation products can imply conservation or even creation of bioactivity across multiple biological end points and thus incomplete mitigation of ecological risk. Therefore, focusing solely on parent compound removal for contaminants of higher relative risk, the most common approach to fate characterization, provides no mechanistic relationship to potential biological effects and is inadequate as a comprehensive metric for reduction of ecological risks. Here, we explore these phenomena for endocrine-active steroid hormones, focusing on examples of conserved bioactivity and related implications for fate assessment, regulatory approaches, and research opportunities.

During the global spread of COVID‐19, high demand and limited availability of melt‐blown filtration material led to a manufacturing backlog of N95 Filtering Facepiece Respirators (FFRs). This shortfall prompted the search for alternative filter materials that could be quickly mass produced while meeting N95 FFR filtration and breathability performance standards. Here, an unsupported, nonwoven layer of uncharged polystyrene (PS) microfibers was produced via electrospinning that achieves N95 performance standards based on physical parameters (e.g., filter thickness) alone. PS microfibers 3–6 μm in diameter and deposited in an ~5 mm thick filter layer are favorable for use in FFRs, achieving high filtration efficiencies (≥97.5%) and low pressure drops (≤15 mm H2O). The PS microfiber filter demonstrates durability upon disinfection with hydroxyl radicals (•OH), maintaining high filtration efficiencies and low pressure drops over six rounds of disinfection. Additionally, the PS microfibers exhibit antibacterial activity (1‐log removal of E. coli) and can be modified readily through integration of silver nanoparticles (AgNPs) during electrospinning to enhance their activity (≥3‐log removal at 25 wt% AgNP integration). Because of their tunable performance, potential reusability with disinfection, and antimicrobial properties, these electrospun PS microfibers may represent a suitable, alternative filter material for use in N95 FFRs. [ABSTRACT FROM AUTHOR]

Radium is a naturally‐occurring radioactive element found in Upper Midwest aquifers, yet exposure risks for unregulated water sources in this region are unknown. A survey of 226/228Ra and other inorganic constituents in 94 private wells was conducted in 2019 across 10 Iowa counties. Within private wells, 53% measured below minimum detectable activity whereas 6.3% have 226/228Ra levels above the United States Environmental Protection Agency Maximum Contaminant Level. 226/228Ra occurrence was not associated with well‐depth or chemical surrogates, but were generally consistent with the lithology and historical water quality trends for aquifers. In 2020, 11 of the 226/228Ra‐impacted wells were re‐sampled to assess the efficacy of in‐home water treatment. Water softeners reduced 226/228Ra to non‐detectable activities, but other inorganic constituents persisted and their removal required more advanced treatment. This study suggests that 226/228Ra occurrence in private wells can reasonably be anticipated from public water supply data if reliable information is available to identify the source aquifer. [ABSTRACT FROM AUTHOR]