Degradation of quinolone antibiotic, norfloxacin, in aqueous solution using gamma-ray irradiation

Abstract

This study reports the efficiency of gamma-ray irradiation to degrade quinolone antibiotic, norfloxacin, in aqueous solution. Laboratory batch experiments were conducted to determine the "pseudo-first" order degradation kinetics of norfloxacin in the concentration ranges of 3.4-16.1 mg L(-1) by gamma-ray irradiation. The dose constant was found to be dependent on the initial concentration of norfloxacin and gamma-ray irradiation dose rate (D r). The saturation of norfloxacin sample solutions with N2, air or N2O, and the presence of tert-butanol and 2-propanol showed that (•)OH played more crucial role in the degradation of norfloxacin. The second order rate constants of (•)OH, eaq (-), and (•)H with norfloxacin were calculated to be 8.81 × 10(9), 9.54 × 10(8), and 1.10 × 10(9) M(-1) s(-1), respectively. The effects of various additives including CO3 (2-), HCO3 (-), NO3 (-), NO2 (-), and thiourea and the pH of the medium on the degradation of norfloxacin were also investigated. Norfloxacin degradation was lower in surface water and wastewater than in ultrapure water. Several degradation byproducts of norfloxacin were identified from which the possible degradation pathway was proposed.

Ag-loaded thermo-sensitive composite microgels for enhanced catalytic reduction of methylene blue

“…Furthermore, the colored form of MB cannot be biodegraded more easily as compared to its reduced colorless form. Several methods have been designed for the removal of MB and other organic pollutants from waste water such as adsorption desorption strategy [3][4][5][6], c-irradiation [7], ozonation [8][9][10], photocatalysis [11][12][13], ion exchange [14], membrane separation [2], reverse or forward osmosis [15], electrochemical methods [16,17], biochemical materials [18][19][20], but all these methods are either very expensive or cannot remove the pollutants completely. Chemical reduction method used to convert these dyes from toxic state to nontoxic or less toxic form is very easy and environmentally friendly, but the reduction of these dyes without catalyst takes much time.…”

Gamma – irradiation induced degradation of diclofenac in aqueous solution: Kinetics, role of reactive species and influence of natural water parameters

“…Higher% degradation of diclofenac at pH 6.68-8 is probably due to higher concentration of OH radicals and O 2 À ions in the solution at this pH [25]. The decrease in% degradation at pH 11 may be due to the fact that H radical can react with OHÀ À to generate e aq À and thus increasing the concentration of e aq À [4]. These increased e aq À then reacts with OH radicals by inter-radical recombination reactions (Eq.…”

“…The worldwide annual production of pharmaceuticals is in thousands of tons which can cause harmful effects in terrestrial as well as in aquatic ecosystems [2,3]. The use of pharmaceuticals has serious consequences because most of them are persistent, bio accumulative and have long range transportable behaviour in the ecosystem [4]. The presence of pharmaceuticals in water indicated their inefficient removal by outdated traditional water purification techniques, i.e.…”

Photocatalytic degradation of norfloxacin and its intermediate degradation products using nitrogen‐doped activated carbon–CuS nanocomposite assisted by visible irradiation

“…It has been reported that removal of NOR by conventional water treatment techniques cannot effectively remove it from aqueous solution because of its aromatic nature. Thus, its existence can cause serious health issues through contaminating drinking water …”

“…On the other hand, the holes caused in the valence band due to reaction with H 2 O on the surface of the catalyst make hydroxyl radicals. The hydroxyl radicals formed are the principal agents for the oxidation of NOR to transform it into by‐products at optimum time and finally to simple non‐polluting compounds at longer time …”