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Degradation of tetracyclines in different water matrices by advanced oxidation/reduction processes based on gamma radiation
Author(s) -
López Peñalver Jesús J.,
Gómez Pacheco Carla V.,
Sánchez Polo Manuel,
Rivera Utrilla José
Publication year - 2013
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.3946
Subject(s) - aqueous solution , chemistry , radiolysis , ultrapure water , radical , nuclear chemistry , reaction rate constant , humic acid , degradation (telecommunications) , mineralization (soil science) , oxytetracycline , hydroxyl radical , radiochemistry , environmental chemistry , kinetics , nitrogen , organic chemistry , environmental engineering , antibiotics , biochemistry , telecommunications , physics , computer science , engineering , fertilizer , quantum mechanics
Background This study analyzes the efficacy of a gamma radiation advanced oxidation/reduction process ( AORP ) to treat waters contaminated with the antibiotics tetracycline ( TC ), chlortetracycline ( CTC ), and oxytetracycline ( OTC ).Results Study results indicate that: (1) radiolysis of the three TCs fits a pseudo‐first‐order kinetic model in which the radiation‐chemical yield decreases with higher absorbed dose; (2) the value of the dose constant depended on the dose rate, which ranged from 3.83 to 1.66 Gy min –1 , and depended to a small extent on the medium pH between pH values of 2.0 and 10.0, since aqueous electrons and hydroxyl radicals both act in TC degradation; (3) the effectiveness of the process was slightly increased at low concentrations of H 2 O 2 ; (4) the presence of Cl − , C O 3 2 , N O 3 − , N O 2 −and humic acid influenced TCs degradation, which was higher at low concentrations of Cl − , C O 3 2 −and HA and markedly decreased at low concentrations of ofN O 3 −and N O 2 − ; (5) the dose constant is lower in natural waters; (6) TOC values for ultrapure water, surface water, groundwater and wastewater showed that it is not possible to obtain complete TC mineralization at the absorbed doses; (7) the toxicity of byproducts formed during the radiolytic process was lower.Conclusions Gamma radiation, an oxidation/reduction procedure, is an effective treatment for removing TC , CTC and OTC from aqueous solutions. TC degradation takes place by both oxidation and reduction pathways, with a predominance of the latter, as demonstrated by the markedly reduced dose constant in the presence of aqueous electron scavengers.