This manuscript reports a study of the ionic conductivity of radio frequency sputter deposited, lithium phosphorous oxy-nitride (LIPON), solid state electrolyte amorphous thin films. Films having compositions near Li 2.5 PO 3.5 N 0.5 were deposited under varying conditions of process gas, substrate bias, and deposition temperature. To understand the variations in ionic conductivity observed, the films were extensively characterized to examine structural and compositional differences, including examination by x-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy, and spectroscopic ellipsometry. For the XPS study, depth profiling was used to allow a critical examination of the role of triply coordinated nitrogen in the ionic conductivity of LIPON. The highest ionic conductivity of 9.8 x 10-6 S/cm was obtained at an elevated deposition temperature and is correlated to a reduced density of defects, as indicated from the optical characterization.

The authors investigated the rejection of six synthetic organic chemicals (SOCs) in a potable water source by a nanofiltration membrane softening process. Each SOC was studied separately for one month—which was subdivided into four recovery periods. The four largest‐molecular‐weight compounds (chlordane, heptachlor, methoxychlor, and alachlor) were completely rejected by the membrane. Ethylene dibromide, the lowest‐molecular‐weight compound studied, was not rejected by the membrane, whereas dibromochloropropane was partially rejected. Mass balances indicated that SOC recovery decreased as SOC molecular weight (MW) increased, which suggested that the three largest‐MW SOCs had been adsorbed by the membrane. The percentage of SOC rejection increased as MW increased, and the rejection of inorganic solutes increased as MW and species charge increased. No effect on solute mass transfer of any solutes resulted from membrane feed‐stream velocities, which were estimated to vary from 0.19 to 0.52 fps.

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As part of a Water Research Foundation project called Post‐Treatment Stabilization of Desalinated Water, current posttreatment issues related to desalination were explored in an effort to provide guidance to the water industry. Although literature on posttreatment exists, there are fundamental knowledge gaps on accepted water quality goals for posttreated finished water related to location, source water, and membrane process. This article provides a current overview of the literature on posttreated desalinated water and discusses posttreatment issues identified and ranked by experienced desalination professionals. Guidance and recommendations were developed for priority issues regarding posttreatment design and operation (including increased characterization of membrane permeate quality), membrane pilot‐study evaluations (including posttreatment evaluations), and increased distribution system monitoring after full‐scale operation. Finished water quality goals and posttreatment processes were developed according to type of source water and membrane process and are recommended on the basis of available literature, industry experience, and research findings.

To evaluate the significance of reverse osmosis (RO) and nanofiltration (NF) surface morphology on membrane performance, productivity experiments were conducted using flat-sheet membranes and three different nanoparticles, which included SiO2, TiO2 and CeO2. In this study, the productivity rate was markedly influenced by membrane surface morphology. Atomic force microscopy (AFM) analysis of membrane surfaces revealed that the higher productivity decline rates associated with polyamide RO membranes as compared to that of a cellulose acetate NF membrane was due to the inherent ridge-and-valley morphology of the active layer. The unique polyamide active layer morphology was directly related to the surface roughness, and was found to contribute to particle accumulation in the valleys causing a higher flux decline than in smoother membranes. Extended RO productivity experiments using laboratory grade water and diluted pretreated seawater were conducted to compare the effect that different nanoparticles had on membrane active layers. Membrane flux decline was not affected by particle type when the feed water was laboratory grade water. On the other hand, membrane productivity was affected by particle type when pretreated diluted seawater served as feed water. It was found that CeO2 addition resulted in the least observable flux decline, followed by SiO2 and TiO2. A productivity simulation was conducted by fitting the monitored flux data into a cake growth rate model, where the model was modified using a finite difference method to incorporate surface thickness variation into the analysis. The ratio of cake growth term (k1) and particle back diffusion term (k2) was compared in between different RO and NF membranes. Results indicated that k2 was less significant for surfaces that exhibited a higher roughness. It was concluded that the valley areas of thin-film membrane surfaces have the ability to capture particles, limiting particle back diffusion.