Effect of Chemical Reaction and Mass Transfer on Ozonation of the Azo Dyes Reactive Black 5 and Reactive Orange 96

Abstract

Ozonation of wastewater containing azo dye has been studied to evaluate the enhancement of ozone mass transfer from O 2 /O 3 gas into water with the presence of chemical reactions in a bubble column reactor. Experiments were performed at different initial dye concentrations and at various gas flow rates. C.I. Reactive Black 5 (RB 5) and C.I. Reactive Orange 96 (RO 96) have been chosen as representative model substances being found in wastewater from textile-finishing wastewater. Results show that the rate of ozone mass transfer increases with increasing initial dye concentration and gas flow rate. Consequently, an enhancement factor E for ozone mass transfer with chemical reaction could be calculated which increases with dye concentration. The chemical reaction between ozone and dye enhanced the mass transfer within the liquid film of the gas liquid boundary. The greatest enhancement factor for wastewater containing RO 96 of 2050 mgL −1 is E = 15.4 compared with E = 9.1 for RB 5 of 3800 mgL −1 , both for gas flow rates of 19 Lh −1 . For lower gas flow rates, higher enhancement factors were observed, particularly for RO 96.Black 5 (RB 5); Reactive Orange (RO 96) zonation is a significant technology applied to many fields in water and wastewater treatment. Ozone reacts directly after forming O and O 2 or indirectly after the production of hydroxyl radicals. Ozone has to be produced at the point of use because of its instability (Kornmüller et al., 1999;Rice et al., 1981). Many of the gas-liquid contactors have been used to transfer ozone into water in order to enable chemical reactions simultaneously and to study reaction O

Decolorization of methyl orange by ozonation in combination with ultrasonic irradiation

“…Although the enhancement factor E increases with dye concentration [40], it is not proportional to dye concentration. Therefore, the apparent first order rate constant k 1 decreased with initial dye concentration.…”

Bubble column reactors for high pressures and high temperatures operation

“…Their values of gas holdup are higher than those reported in literature at atmospheric conditions ((Zahradník et al, 1997) for example). Choi and Wiesmann (2004) have studied the influence of chemical reaction in an ozonation bubble column. They propose a method to calculate the mass transfer coefficient without reaction, in the case when reactive gases are used.…”

Brine Recycling from Industrial Textile Wastewater Treated by Ozone. By-Products Accumulation. Part 1: Multi Recycling Loop

“…Color, COD, TOC or BOD removal Simulated [17,[21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] Industrial [19,[39][40][41][42][43][44][45][46][47] Kinetic study Simulated [25][26][27]30,31,33,35,37,[48][49][50][51][52][53][54][55][56][57][58][59][60][61][62] Products, degradation mechanism Simulated…”