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Adsorption Of Lead (Ii) Ions By Organosilicate Nanoporous Materials, Larry Keith Isaacs
Adsorption Of Lead (Ii) Ions By Organosilicate Nanoporous Materials, Larry Keith Isaacs
Civil & Environmental Engineering Theses & Dissertations
As-synthesized organosilicate nanoporous (OSNP) materials HMS (hexagonal mesoporous structure) and MCM-41 were used as adsorbents for removal of lead (II) ions in laboratory batch and column studies. Mesoporous organosilicates were prepared from tetraethylorthosilicate (TEOS) and either an ionic (cetyltrimethyl-ammonium) or neutral (dodecylamine) surfactant. Batch reaction distribution coefficients for MCM-41 were KD = 51.5 L/g (SD = 26.3) at 24 h and KD = 73.7 L/g (SD = 40.5) at 7 d. OSNP lead (II) ion adsorption increased from pH = 3 until pH ca. 7.5 after which a sharp decrease in adsorption was noted. OSNP materials reflected a …
Analysis Of Ultraviolet Energy Distribution In Uv Disinfection Systems Using Monte Carlo Ray -Trace Method, Khoi Trung Nguyen
Analysis Of Ultraviolet Energy Distribution In Uv Disinfection Systems Using Monte Carlo Ray -Trace Method, Khoi Trung Nguyen
Civil & Environmental Engineering Theses & Dissertations
Determination of fluence rate in ultraviolet (UV) disinfection systems is a crucial part in evaluating disinfection efficiency of the systems. A robust Monte Carlo Ray Trace (MCRT) method has been developed to determine fluence rates in three-dimensional space of the systems. This is a statistical sampling method in which millions of random light energy bundles are simulated from the axis of each UV lamp and traced through the system until their energies reduce to a minimum threshold level. Inherent phenomena including refraction through quartz tubes, specular reflection at quartz tube surfaces, and absorption by quartz and water, along with specific …