ABSTRACT
Significant efforts have been committed to the research and development of many advanced oxidation processes, including photocatalytic oxidations with titanium dioxide or the hydrogen peroxide and ferrous/ferric ion (H2O2/Fe2+(Fe3+)/UV (photo-assisted Fenton) process. This study reports the development of a novel photochemical system for complex treatment of heavily contaminated wastewaters based on the use of UV-C light and H2O2. Special attention was focused on the technology employed, including the reactor design, process controls, and performance optimization. The effects of process parameters were studied using 4-chlorophenol (4CP) as model compound, and verification of this treatment technology was assessed using actual contaminated water. Among the most influential parameters were the 4CP concentration, reaction mixture volume, H2O2 concentration, and irradiation intensity. In contrast, for H2O2 dosing (proportional continuous or cumulative one-time), the flow rate did not significantly affect process efficacy.
Subject(s)
Photochemical Processes , Waste Disposal, Fluid/methods , Wastewater/chemistry , Chlorophenols/chemistry , Hydrogen Peroxide , Molecular Structure , Oxidation-Reduction , Water Pollutants, Chemical/chemistryABSTRACT
An amperometric biosensor based on genetically-modified enzymes was used for the in situ detection of trace vapours from a number of explosive compounds. The vapour samples that were generated from a purpose-built vapour generator were collected and pre-concentrated using a trap able to concentrate samples at a rate of 60-fold per minute of sampling. The amperometric biosensor achieved a remarkably low vapour detection limit of 6 parts per trillion from a room temperature sample. The specific activity of the reported enzyme toward a number of explosive compounds was also confirmed using absorbance measurements.
