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Seawater desalination technology is important for solving water shortage problems. RO desalination is the most frequently used process for obtaining fresh water from salt water. Electrolysis is also one way of reusing the enriched brine. Alkali-activated products can be made by producing NaOH after electrolysis. There are three kinds of brine electrolysis methods including diaphragm, membrane, and mercury methods. This study was conducted using a 200 mL electrolysis diaphragm cell. Tedlar bags were used in order to gather gases such as Cl2, O2, and H2. The head was less than 10 mm when a diaphragm with a 10 μm pore size was used. The data in this study was collected to analyze the relationships between concentration, chloride removal, and current density (CD). Our results showed that pore size influenced the head at the anode. Chloride removal was not high even when a high CD was applied. When the CD was 200 mA/cm2, the maximum NaOH concentration was 1.85%. However, the NaOH concentration was just...

We characterized alkali-activated slag paste containing dredged marine sediment according to Na2O concentration by mass of slag in the mixture. The compressive strengths of 3-d cured AAS–sediment paste specimens were similar to those of 28-d cured AAS–sediment paste specimens. The optimum Na2O concentration by mass of slag was 6–8%. Leaching testing of samples cured for 3 d confirmed that heavy metals (Cr, Cu, Cd, and Pb) were below the detection limits for all these metals. X-ray diffraction, scanning electron microscopy, and Fourier transform infrared spectroscopy analyses revealed that the microstructure, fracture surface, and silicate band of calcium silicate hydrate as the main hydrate of the AAS–sediment paste were similar among the various samples. Despite this, Ca/Si molar ratios and quantitative analysis results differed among samples with different Na2O concentrations by mass of slag.

Fine dredged sediment was immobilized using ground granulated blast furnace slag as a new binder for supplementary cementitious materials in a 3.5% NaOH solution to study its solidification/stabilization (S/S) and uses in various industrial applications. The aim of this study is to compare effect of mixing conditions of the saturated-surface-dry of dredged sediment to determine the proper mixing method in the S/S process. Measurements of mechanical strength, heavy metal leachability, and microstructural characterization of the dredged sediment treated with alkali-activated slag (AAS) paste were carried out. The maximum value of the mechanical strength was obtained when the same amount of the NaOH solution as the saturated-surface-dry of the dredged sediment was added. The leaching experiment results showed that heavy metals were immobilized in the AAS paste, and that Cr, Cd, and Pb were not detected. The results of the analysis indicate the relationship between mechanical strength and (Ca + Na)/(S...