tailieunhanh - Phsicochemical Treatment of Hazardous Wastes - Chapter 14 (end)

Khi quá trình oxy hóa tiên tiến (AOPs) tiếp tục nhập vào thị trường thương mại, điều trị hiệu quả trở thành một yếu tố quan trọng để lựa chọn một quá trình có hiệu quả chi phí tốt hơn. Để phân tích hiệu quả chi phí, so sánh giữa AOPs lựa chọn đã được báo cáo trong những năm gần đây. Một số của các biến, bao gồm cả điều kiện ban đầu, độ pH, oxy hóa, và nồng độ chất xúc tác, đã được phân tích kết hợp với các thông số động học của quá trình này | 14 Combinations of Advanced Oxidation Processes Introduction As advanced oxidation processes AOPs continue to enter the commercial market treatment efficiency becomes an important factor for selecting a process with better cost efficiency. To analyze the cost efficiency comparisons between selected AOPs have been reported in recent years. A number of variables including initial conditions pH oxidant and catalyst concentrations have been analyzed in combination with kinetic parameters of the process. The kinetics of each process are described by the rate constants and or the reaction half times. These investigations have been conducted under identical experimental conditions so that treatment efficiency can be compared under the same conditions. In addition combinations of various AOPs have also been analyzed with respect to cost efficiency. This comparison was carried out by combining various oxidants such as oxygen ozone and hydrogen peroxide H2O2 with catalysts such as ultraviolet UV Fe2 and TiO2. In general synergic effects exist when two oxidation systems were combined. This synergy was reflected in a marked increase in the free-radical reaction pathway. The effect was also observed to increase with the complexity of the oxidation systems used. The only exception arose in the comparison of Fenton s reagent system with a combined Fenton s reagent ozone system in which case there seems to be interference of ozone with Fenton s reagent through oxidation of Fe2 which reduces the amount of Fe2 to decompose H2O2 into hydroxyl radicals. Fundamental Theory The destruction kinetics of organic pollutants may be inhibited in wastewaters containing complex compounds. Under such conditions the combination 2004 by CRC Press LLC of UV O3 and H2O2 systems could be a better process because hydroxyl radicals are generated by several mechanisms. As a result UV O3 H2O2 is less affected by color and turbidity in wastewater than UV O3 or UV