ABSTRACT
The current article studies the optimization of a new coagulant agent for water purification and wastewater remediation. Design of experiments is used for optimizing the production of this new tannin-based coagulant by using Acacia mearnsii de Wild tannin extract, NH(4)Cl and formaldehyde. The effectiveness of this product was confirmed on dye-polluted wastewater and surfactant wastewater. This cationic coagulant seems to be sensitive to temperature and tannin-NH(4)Cl ratio (g of ammonium chloride per g of tannin extract). NH(4)Cl ratio was found to be more influent than temperature and no interaction is presented between these two parameters. For each system, an optimum combination NH(4)Cl ratio and temperature was found: 24.9°C and 2 g g(-1) for dye removal and 36.4°C and 1.87 g g(-1) for surfactant elimination. The optimal conditions were merged to produce a combined coagulant that was tested on dye, surfactant, surface river water and municipal wastewater. Predicted levels of remediation were experimentally confirmed.
Subject(s)
Industrial Waste/analysis , Tannins/chemistry , Adsorption , Algorithms , Buffers , Coloring Agents/isolation & purification , Environmental Restoration and Remediation , Indicators and Reagents , Metals/analysis , Models, Statistical , Nephelometry and Turbidimetry , Solutions , Surface-Active Agents/chemistry , Textile Industry , Waste Disposal, Fluid , Water Purification/methodsABSTRACT
Phosphor screens find application in many fields because of their ability to convert incident radiation to wavelengths that are readily measured by modern detectors. While the response of such screens in the X-ray region has been widely studied, much work still remains to be done regarding their response in the vacuum ultraviolet and soft X-ray regions, where the response is predicted to be non-linear owing to the presence of elemental absorption edges. Here, an experiment using synchrotron radiation to determine the response of thin Y(3)Al(5)O(12):Ce (1-21 mg cm(-2)) and Y(2)O(3):Eu (2.64 mg cm(-2)) powder phosphor screens in the spectral range 20-900 A (13.8-620 eV) is reported. Also, a custom-built camera is described which permits simultaneous collection of the forward- and backward-emitted light and that enables measurements to be made at various positions across the screens and at several screen/incident beam angles. Finally, features in the response spectra are identified, and efficiencies across the spectral range indicated for different screen thicknesses and operating modes are plotted, before a curve of the intrinsic radiant efficiency of Y(3)Al(5)O(12):Ce is produced. The results are discussed in the context of other measurements.