Intensification of sonochemical decolorization of anthraquinonic dye Acid Blue 25 using carbon tetrachloride

Abstract

In this work, the influence of CCl(4) on the sonochemical decolorization of anthraquinonic dye Acid Blue 25 (AB25) in aqueous medium was investigated using high frequency ultrasound (1700 kHz). This frequency, reputed ineffective, was tested in order to introduce the ultrasound waves with high frequency in the field of degradation or removal of dyes from wastewater, due to its limited use in this field, and to increase the application of high frequency ultrasound wave in the field of environmental protection. The effects of various parameters such as the concentration of CCl(4), frequency (22.5 and 1700 kHz), solution pH, temperature and tert-butyl alcohol adding on the decolorization rate of AB25 was studied. The obtained results clearly demonstrated the significant intensification of AB25 decolorization in the presence of CCl(4). The enhancement effect of CCl(4) increased by decreasing temperature and by increasing the CCl(4) concentration. The pH has a significant influence on the bleaching of dye both in the absence and presence of CCl(4). The three investigated dosimeter methods (KI oxidation, Fricke reaction and H(2)O(2) production) well corroborate the improvement of the sonochemical effects in the presence of CCl(4). The best sonochemical decolorization rate of AB25 in aqueous solution both in the absence and presence of CCl(4) is observed to occur at 1700 kHz compared to 22.5 kHz. The sonochemical oxidation of CCl(4) generates oxidizing species in the liquid phase that are highly beneficial for oxidation of hydrophilic and non-volatile pollutant, such as dyes, because they are less susceptible to free radical attack due to lower stability of the generated free radicals.

Recent advances and prospects of catalytic advanced oxidation process in treating textile effluents

“…There are more than 10,000 dyes with an annual production of more than 7 × 10 5 metric tonnes that are commercially available worldwide (Engin et al 2008). It is estimated that approximately 15% of the dyestuffs are lost in industrial effluents during manufacturing processes (Ghodbane and Hamdaoui 2009). Such estimation indicates that 100 L of wastewater are produced for every kilogram of textile product, which is equivalent to 3.7 million liters each day worldwide (Amaral et al 2014).…”

Sonochemical degradation of the antibiotic cephalexin in aqueous solution

“…whether the pollutant is present as ionic species or as a molecule (Ghodbane and Hamdaoui, 2009). Cephalexin is a non-volatile compound and the region of sono-decomposition would be at the cavitation bubble interface where the hydroxyl radical concentration is at a maximum.…”

Intensification of textile effluent chemical oxygen demand reduction by innovative hybrid methods

“…At pH 5-10, the initial COD reduction was found to be very less compared to acidic conditions. This is due to the lower concentration of hydroxyl radicals at these conditions because only about 10% of the hydroxyl radicals that are generated in the bubble can diffuse into the bulk liquid [1,34,35]. In addition, at pH 5-8, a higher number of hydroxyl radicals recombine to form H 2 O 2 that leads to decrease in hydroxyl species concentration [1].…”

“…This is due to the lower concentration of hydroxyl radicals at these conditions because only about 10% of the hydroxyl radicals that are generated in the bubble can diffuse into the bulk liquid [1,34,35]. In addition, at pH 5-8, a higher number of hydroxyl radicals recombine to form H 2 O 2 that leads to decrease in hydroxyl species concentration [1]. Similar trends were observed for the ultrasonic degradation of many organic pollutants, such as methyl orange, azo dyes, and nitro phenol [30,31,36].…”

“…The textile industry wastewater contains various kinds of synthetic dyestuffs and other chemicals and the main processes generate wastewater in textile unit include washing, bleaching, dyeing and finishing [1]. There are about more than 100,000 different commercial dyes existing and over 7 × 10 5 tons of dyestuffs are produced annually [2,3].…”