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Water filtration membranes with advanced ion selectivity are urgently needed for resource recovery and the production of clean drinking water. This work investigates the separation capabilities of cross-linked zwitterionic copolymer membranes, a self-assembled membrane system featuring subnanometer zwitterionic nanochannels. We demonstrate that selective zwitterion–anion interactions simultaneously control salt partitioning and diffusivity, with the permeabilities of NaClO 4 , NaI, NaBr, NaCl, NaF, and Na 2 SO 4 spanning roughly three orders of magnitude over a wide range of feed concentrations. We model salt flux using a one-dimensional transport model based on the Maxwell–Stefan equations and show that diffusion is the dominant mode of transport for 1:1 sodium salts. Differences in zwitterion–Cl − and zwitterion–F − interactions granted these membranes with the ultrahigh Cl − /F − permselectivity ( P Cl- /P F- = 24), enabling high fluoride retention and high chloride passage even from saline mixtures of NaCl and NaF. 

As part of an NSF CAREER project [blinded] , [blinded university] developed a one-week chemical engineering summer workshop targeted at middle school girls with the goal of bolstering participation and interest in the field by presenting chemical engineering as a creative and dynamic field. This paper will present a spherification activity which introduces chemical reactions, membranes, resource management, engineering design, and more. Furthermore, links to the full set of activities developed for the week that can be used individually or collectively are provided. In the summer program, students engage in experiments providing simplified background knowledge on foreign material such as chemical reactions, polymer morphology, separations, and thermodynamics. The students then work on hands-on activities to solve engineering design problems using learned information. For the final activity, students collaboratively design a process to scale up a spherification experiment