subject: Photochemical Oxidation Of Dyeing Wastewater Application [print this page] Abstract: Some are simple and good photochemical oxidation process: UV/O3 method, light-Fenton photocatalytic oxidation method and discussed the problems in this area, research focus and direction, and oxygen on the photochemical Chemical industry Treatment of dyeing wastewater Arts prospect.
Printing and dyeing industry is a large industrial wastewater, printing and dyeing fabrics for every 100 meters of production, the average wastewater 3 ~ 5m3, the national printing and dyeing wastewater was about 300 to 4,000,000 m3 / d. The typical characteristics of dyeing wastewater with high concentrations of organic matter, poor biodegradability, color depth, complex components, wastewater containing dyes, sizing, additives, acids, alkalis, salts and other impurities and fibers and dyes in the nitro and amine compounds and copper, chromium, arsenic and other heavy metals have greater toxicity, are biodegradable organic waste, thus the effective treatment of dyeing wastewater in industrial wastewater treatment has been one of the focus.
1 country Dyeing Wastewater Treatment Status quo
Domestic engineering practice of dyeing wastewater treatment mainly by biochemical methods (anaerobic - aerobic system) and chemical methods (coagulation and sedimentation or flotation) as the main body of the secondary treatment process, with technology maturity, operational management simple, and low operating cost advantages. However, in recent years, printing and dyeing industry, rapid technological innovation, widespread adoption of Alkali, synthetic polyvinyl alcohol (PVA) sizing and various refractory, heavy use of anti-oxidation additive, printing and dyeing wastewater organic matter concentration increased sharply, and the biochemistry of further deterioration, so the original can
To meet the processing requirements of the traditional secondary treatment processing system weakened, it is difficult emissions standards. According to the survey, in recent years most of the printing and dyeing wastewater treatment, COD removal decreased from the previous 70% to 50% or less, decolorization difference is the weak link. Coagulation of the wastewater pollutant removal efficiency of hydrophilic low, the treatment effect is difficult to guarantee. Activated Carbon Adsorption, Membrane Separation of advanced treatment process of high costs there, activated carbon deactivation, fouling problems, and only the separation of the transfer of pollutants, and there is no real degradation. In view of this, research and development of simple and efficient pre-treatment enhanced the depth dyeing wastewater treatment process to become an urgent task.
2 photochemical oxidation of printing and dyeing wastewater
Photochemical oxidation technology is advanced oxidation process, is the new modern water treatment technology, which through the oxidant (O3, H2O2, etc.) in the UV (or visible) light excitation and a catalyst (Fe2 +, Fe3 +, semiconductor, etc.) of the catalytic under, resulting in a strong oxidizing hydroxyl radical (. H),. OH the standard oxidation potential of up to 2.8eV, is the element fluorine than the strongest oxidant, can not choose to be completely oxidized to CO2 vast majority of organic matter , H2O, and other inorganic substances, reaction speed, time-consuming and short, mild reaction conditions (ambient temperature and pressure), easy to control operating conditions, no secondary pollution. Color dye printing and dyeing wastewater from dye molecules conjugated system - unsaturated group-N = N-,> C = C C = O, etc. chromophores, photochemical oxidation of? OH conjugate can effectively break the architecture, making them colorless organic molecules, and further mineralization to H2O, CO2 and other inorganic materials. Photochemical oxidation process on the characteristics and the molecular structure of dye determines the photochemical oxidation in printing and dyeing wastewater treatment process has other advantages are unmatched.
Recent years, scholars in the photochemical oxidation treating printing and dyeing waste water to a large number of experimental studies and theoretical exploration, mainly in the following areas.
2.1UV/O3 method UV/O3 is ozone (O3) and ultraviolet (UV) radiation combined advanced oxidation process. O3 is a strong oxidant, either directly with the organic reaction, can also be produced during the reaction. OH oxidation of organic matter, degradation of organic matter with a good, open-loop bleaching and disinfection effects, and the excess O3 automatically broken down into the water O2, no secondary pollution.
Ozone oxidation and decomposition through the following two ways Organic:
(1) under acidic conditions and organic matter directly to nucleophilic or electrophilic reaction, its degradation; (2) in the base, under the action of light or other factors, resulting in active hydroxyl radical oxidation of organic matter by-OH:
Photochemical Oxidation Of Dyeing Wastewater Application
