Enhanced decomposition of reactive blue 19 dye in ultrasound assisted electrochemical reactor

Abstract

Textile industry effluents contain reactive dyes that may harm our receiving waters. A typical reactive blue (RB) 19 dye is frequently detected in significant concentrations in textile industry effluents. Such dyes have generally shown resistance to decomposition and tend to persist in the environment for long periods and multiply the impacts to water and environment. Therefore, the present investigation focused on high-rate decomposition of a typical reactive dye RB 19 under various ultrasound and electrochemical process conditions. The decomposition of un-hydrolyzed and hydrolyzed forms of reactive blue (RB) 19 dye by ultrasound assisted electrochemical process was investigated using various parameters including dye concentration, pH, ultrasonic frequency and reaction time. Reaction kinetics, organic carbon and mechanism for dye decomposition were determined using UV-Visible spectrophotometry, TOC (total organic carbon) analysis and gas chromatography-mass spectrometry (GC-MS). Almost complete 90% color removal and a maximum of 56% TOC removal for 50 mg L(-1) dye concentration of un-hydrolyzed RB 19 dye was achieved at an ultrasonic frequency of 80 kHz, pH of 8 after 120 min. GC-MS analysis showed that a sonoelectrochemical treatment of un-hydrolyzed RB 19 dye for 30 min resulted in the formation of products e.g. acetic acid, benzoic acid etc. with the complete removal of dye. For hydrolyzed dye, a treatment of 10 min was enough and the results were comparable with 30 min treatment of un-hydrolyzed dye. Kinetics of ultrasound assisted electrolysis showed that the dye decomposition followed 1st order. The ultrasound assisted electrolysis for dye decomposition and hence decolorization proved to be more effective and the total energy consumption reduced to half as compared with simple electrolysis/sonochemical decomposition. Therefore, ultrasound assisted electrolysis was found to be more effective technique for dye decomposition of an otherwise environmentally persistent reactive dye.

Electrochemical degradation of C.I. Reactive Orange 107 using Gadolinium (Gd3+), Neodymium (Nd3+) and Samarium (Sm3+) doped cerium oxide nanoparticles

“…In the former, the catalyst couple merely plays the role of an electron carrier (mediator), whereas the transitory formation of catalyst-substrate adduct occurs in the latter [25]. In addition, the electrons may then react with species adsorbed on the surface, yielding radicals such as O 2 -as a result of the presence of hydroxyl groups, water, and oxygen at the surface of the Gd 3? , Nd 3?…”

“…Reactive dyes are extensively used in the textile industry due to the presence of reactive groups in their molecules which bind to fibers through covalent bonds. The main problem associated with the use of reactive dyes is their low affinity for fabrics resulting in relatively high dye concentrations in textile wastewater [2]. Reactive dyes exhibit a wide range of different chemical structures, primarily based on substituted aromatic and heterocyclic groups.…”

Sonoelectrochemistry in Environmental Applications

“…Lissamine Green B [10], Trupocor Red [10], Reactive Black 5 [10], Acid Black [10], Methyl Orange [10][11][12], Rhodamine B [12], Methylene Blue [12], Reactive Brilliant X-3B [12], and Reactive Blue 19 [13] have been used as reactive dyes for acoustic cavitation coupled with electrochemical treatment. Hydrodynamic cavitation has also been used to enhance the electrochemical treatment of Brilliant Red X-3B [9].…”

“…Hydrodynamic cavitation has also been used to enhance the electrochemical treatment of Brilliant Red X-3B [9]. For all these studies, various electrode materials (Ti-IrO 2 [9], graphite [10], platinum [12], PbO 2 [13]) and three-dimensional electrodes [11] were employed and the effect of several parameters were studied, including the ultrasonic power/intensity, the cell design, pH, initial dye concentrations, and so on. It was observed that pseudo-first-order kinetics were obtained in most cases where di-azo dyes showed slow degradation rates compared with mono-azo dyes [10].…”

Ultrasound in Electrochemical Degradation of Pollutants

“…Recently, Siddique et al (2011) reported the decomposition of un-hydrolyzed and hydrolyzed forms of reactive blue (RB) 19 dye by ultrasound assisted electrochemical process using lead oxide as working electrode. The experiments were conducted at various pH values in the range of 3-9 and various ultrasonic frequencies (20-80 kHz) using 50 mg L -1 dye concentration for 120 min.…”