This is the first report using an alternate soaking process (ASP) to mineralize the surfaces of thin film composite (TFC) polyamide membranes with silver chloride (AgCl) for forward osmosis (FO). Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis confirmed even distribution of AgCl particles on the top of the membrane surfaces. Surface roughness, contact angle, and zeta potential measurements show that the AgCl mineralized membranes have smoother, more hydrophilic, and more negatively charged surfaces than unmodified membranes. Under FO operation (with deionized water feed and 1 M NaCl draw), we found that the mineralized membranes exhibit higher salt rejection and water flux than the original membranes. Fouling experiments with bovine serum albumin (BSA) show that the mineralized membranes have lower water flux decline ratios in BSA aqueous solution and higher water flux recovery ratios after simple hydraulic washing than unmodified TFC membranes.
This paper introduces a wireless, solid-state, portable, and automated device capable of measuring the total ammonia [ammonia (NH3) and ammonium (NH4+)] levels of fluids, including biological samples. This device reliably measures the total ammonia of biological samples (e.g., urine) faster than the current ammonia quantification techniques. Medical professionals typically estimate NH4+ levels using error-prone indirect measurement techniques (i.e., urine anion gap), which are time-consuming and are seldom suitable for periodic measurements. Several instantaneous measurements of total ammonia levels in a patient urine could be utilized as an early warning for both acid-base and/or potassium disturbances. Given the device’s operation mechanism, it is able to quantify the total ammonia concentration within a biological sample in only 5 s and can simultaneously transmit data to other devices via Bluetooth. The analytical operation demonstrated high sensitivity, high specificity, fast reversibility, rapid response time, and has enabled the accurate determination of total ammonia concentration in urine samples produced by subjects who had consumed diets of variable protein compositions.
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