Synthesis and Characterization of Pumice-Supported nZVI for Removal of Copper from Waters

The target of this work was to study the synthesis and characterization of pumice-supported nanoscale zero-valent iron (nZVI) and the effectiveness of nZVI coated pumice to remove copper from water. The impacts of pumice dose, pumice surface chemistry, pH, and water source on copper removal were studied. Natural pumice particles were used as granular support media and coated with nZVI. Results of nZVI coated pumice characterization showed nZVI coated successfully on pumice surface being proved with characterization methods such as SEM-EDS, XPS, and XRF. nZVI coating overwhelmed the surface chemistry properties of the underlying pumice particles. Higher surface areas and more iron content were obtained in nZVI coated pumice. nZVI coating significantly increased copper uptake compared to uncoated particles. High removal capacity has been observed for all tested pH values. Control experiments indicated that nZVI bound on pumice surfaces is stable at pH values of typical natural waters. The nZVI coated pumice was found to be effective in removing copper from waters having a wide range of specific UV absorbance (SUVA) values. Overall, the results indicated that nZVI coated pumice particles are maybe alternative adsorbents to remove copper

Halogenated By-Products in Chlorinated Indoor Swimming Pools: A Long-Term Monitoring and Empirical Modeling Study

Monitoring the disinfection process and swimming pool water quality is essential for the prevention of microbial infections and associated diseases. However, carcinogenic and chronic-toxic disinfection by-products (DBPs) are formed with reactions between disinfectants and organic/inorganic matters. DBP precursors in swimming pools originate from anthropogenic sources (body secretions, personal care products, pharmaceuticals, etc.) or chemicals used in pools. Temporal (48 weeks) water quality trends of trihalomethanes (THMs), haloacetic acids (HAAs), haloacetonitriles (HANs), and halonitromethanes (HNMs) in two swimming pools (SP-A and SP-B) and precursor-DBP relationships were investigated in this study. Weekly samples were taken from swimming pools, and several physical/chemical water quality parameters, absorbable organic halides (AOX), and DBPs were determined. THMs and HAAs were the most detected DBP groups in pool water. While chloroform was determined to be the dominant THM compound, dichloroacetic acid and trichloroacetic acid were the dominant HAA compounds. The average AOX concentrations were measured to be 304 and 746 μg/L as Cl- in SP-A and SP-B, respectively. Although the amount of AOX from unknown chlorinated by-products in SP-A did not vary temporally, a significant increase in unknown DBP concentrations in SP-B was observed over time. AOX concentrations of chlorinated pool waters were determined to be an important parameter that can be used to estimate DBP concentrations