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Abstract
<p xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" class="first" dir="auto"
id="d7984727e93">In this work, the electrochemical degradation of antibiotic ceftazidime
has been studied
using a novel rare earth metal Ce and carbon nanotubes codoped PbO2 electrode. A competitively
high oxygen evolution potential (2.4 V) and enhanced catalytic surface area were obtained,
evidence by LSV and CV electrochemical characterization. The G/CNT-Ce/PbO2-Ce electrode
possessed a more compact structure and a smaller grain size than the other PbO2 and
Ce-PbO2 electrodes, exhibiting a prolonged service lifetime, evidence by accelerated
lifespan test and recycling degradation experiment. As electrolysis time reached 120 min,
the removal efficiency of ceftazidime and TOC arrived at 100.0% and 54.2% respectively
in 0.05 M Na2SO4 solution containing 50 mg⋅L-1 ceftazidime. The effect of applied
current density, pH value, initial ceftazidime concentration and chloride contents
on the degradation performance were systematically evaluated. The results demonstrated
that electrochemical oxidation of ceftazidime over the G/CNT-Ce/PbO2-Ce electrode
was highly effective, and the mineralization rate was greatly improved, compared with
pristine PbO2 electrode. Considering the toxicity was increased after 30 min electrolysis,
the intermediates were quantitatively investigated through HPLC-MS, GC-MS and IC technology.
According to the identified products, a reaction mechanism has been proposed and pyridine
and aminothiazole were detected with concentration from approximately 1 to 3 mg⋅L-1,
which were regarded as toxic byproducts during electrooxidation. Further electrocatalyzing
by ring cleavage reaction and complete mineralization to CO2, NO3- and NH4+ was proposed,
which demonstrated the G/CNT-Ce/PbO2-Ce electrode exhibited high efficiency for ceftazidime
removal in mild conditions.
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