Assessment of solar driven TiO2-assisted photocatalysis efficiency on amoxicillin degradation

Abstract

The objective of this work was to evaluate the efficiency of a solar TiO2-assisted photocatalytic process on amoxicillin (AMX) degradation, an antibiotic widely used in human and veterinary medicine. Firstly, solar photolysis of AMX was compared with solar photocatalysis in a compound parabolic collectors pilot scale photoreactor to assess the amount of accumulated UV energy in the system (QUV) necessary to remove 20 mg L −1 AMX from aqueous solution and mineralize the intermediary byproducts. Another experiment was also carried out to accurately follow the antibacterial activity against Escherichia coli DSM 1103 and Staphylococcus aureus DSM 1104 and mineralization of AMX by tracing the contents of dissolved organic carbon (DOC), low molecular weight carboxylate anions, and inorganic anions. Finally, the influence of individual inorganic ions on AMX photocatalytic degradation efficiency and the involvement of some reactive oxygen species were also assessed. Photolysis was shown to be completely ineffective, while only 3.1 kJUVL −1 was sufficient to fully degrade 20 mg L −1 AMX and remove 61 % of initial DOC content in the presence of the photocatalyst and sunlight. In the experiment with an initial AMX concentration of 2 40 mg L −1 , antibacterial activity of the solution was considerably reduced after elimination of AMX to levels below the respective detection limit. After 11.7 kJUVL −1 , DOC decreased by 71 %; 30 % of the AMX nitrogen was converted into ammonium and all sulfur compounds were converted into sulfate. A large percentage of the remaining DOC was in the form of low molecular weight carboxylic acids. Presence of phosphate ions promoted the removal of AMX from solution, while no sizeable effects on the kinetics were found for other inorganic ions. Although the AMX degradation was mainly attributed to hydroxyl radicals, singlet oxygen also plays an important role in AMX self-photosensitization under UV/ visible solar light.

Recent Overview of Solar Photocatalysis and Solar Photo-Fenton Processes for Wastewater Treatment

“…The use of CPC solar photoreactors was shown to be effective for TiO 2 solar photocatalytic degradation of several organic contaminants such as antibiotics [167], azo dyes [168], water disinfection [169,170], pesticides [8,171], humic acids [172], agro-food industry effluents [173], and ferricyanide [174]. 17 International Journal of Photoenergy Pereira and coworkers [167] studied the TiO 2 solar photocatalytic degradation of the antibiotic amoxicillin in aqueous solutions at neutral conditions (pH 7.5).…”

“…17 International Journal of Photoenergy Pereira and coworkers [167] studied the TiO 2 solar photocatalytic degradation of the antibiotic amoxicillin in aqueous solutions at neutral conditions (pH 7.5). These authors reported that the solar UV radiation alone was unable to attack the antibiotic molecules during the same treatment period as in the TiO 2 solar photocatalysis.…”

A Plug flow reactor model for UV-based oxidation of amoxicillin

“…In this study, the effects of matrix parameters such as humic acids as a model of natural organic matter (NOM) and alkalinity, which are the major background components of wastewaters were measured. The literature only provides studies performed for the purpose of investigating the process efficiency with spiked real water samples and amoxicillin as the target molecule [32,33]. This study focuses on the evaluation of UV and UV/H 2 O 2 processes by combining several aspects in addition to the treatment efficiency.…”

Process enhancement at near neutral pH of a homogeneous photo-Fenton reaction using ferricarboxylate complexes: Application to oxytetracycline degradation

“…A schematic representation and a detailed description of the pilot plant can also be consulted elsewhere [26]. The accumulated UV energy (QUV,n, kJ L -1 ) was calculated according to Eq.…”