Simultaneous Removal of Antibiotic Resistant Bacteria, Antibiotic Resistance Genes, and Micropollutants by FeS₂@GO-Based Heterogeneous Photo-Fenton Process

Abstract

The co-occurrence of various chemical and biological contaminants of emerging concerns has hindered the application of water recycling. This study aims to develop a heterogeneous photo-Fenton treatment by fabricating nano pyrite (FeS2) on graphene oxide (FeS2@GO) to simultaneously remove antibiotic resistant bacteria (ARB), antibiotic resistance genes (ARGs), and micropollutants (MPs). A facile and solvothermal process was used to synthesize new pyrite-based composites. The GO coated layer forms a strong chemical bond with nano pyrite, which enables to prevent the oxidation and photocorrosion of pyrite and promote the transfer of charge carriers. Low reagent doses of FeS2@GO catalyst (0.25 mg/L) and H2O2 (1.0 mM) were found to be efficient for removing 6-log of ARB and 7-log of extracellular ARG (e-ARG) after 30 and 7.5 min treatment, respectively, in synthetic wastewater. Bacterial regrowth was not observed even after a two-day incubation. Moreover, four recalcitrant MPs (sulfamethoxazole, carbamazepine, diclofenac, and mecoprop at an environmentally relevant concentration of 10 μg/L each) were completely removed after 10 min of treatment. The stable and recyclable composite generated more reactive species, including hydroxyl radicals (HO•), superoxide radicals (O2 • –), singlet oxygen (1O2). These findings highlight that the synthesized FeS2@GO catalyst is a promising heterogeneous photo-Fenton catalyst for the removal of emerging contaminants.

Efficient Degradation of Intracellular Antibiotic Resistance Genes by Photosensitized Erythrosine-Produced 1O2

“…The removal rate constant of ARB ( k (ARB)) reached 4.560 min –1 , which was about 14.7 times higher than that of iARGs ( k 1 (iARGs) = 0.310 min –1 ) and 50.2 times higher than that of eARGs ( k 1 (eARGs) = 0.091 min –1 ). iARG degradation is generally much more difficult than ARB inactivation in disinfection systems, ,,, while opposite from our result, faster removal of eARGs than ARB has been widely reported in advanced oxidation systems. , The difference in the relative order of eARG and ARB removal rates may arise from the different ROS involved as discussed later.…”

“…iARG degradation is generally much more difficult than ARB inactivation in disinfection systems, 12,14,18,34 while opposite from our result, faster removal of eARGs than ARB has been widely reported in advanced oxidation systems. 21,51 The difference in the relative order of eARG and ARB removal rates may arise from the different ROS involved as discussed later.…”

Development of Carbon Nanotube/Graphene‐Based Alginate Interpenetrating Hydrogels for Removal of Antibiotic Pollutants

“…Each measurement was repeated three times. The swelling ratio (SR) of the hydrogel was calculated according to the following formula (6),…”

“…High concentrations of antibiotics in an aquatic system can lead to decreased bacterial diversity, difficult development of fish embryos, and fully stopped growth of algae [5] . Moreover, the presence of antibiotics and their transformation products in the environment induces the development of antibiotic‐resistant bacteria and genes, which pose serious risk to both human and animal health [6] . Without any doubts, there is an urgent need for the development of effective treatment methods to remove such pollutants from the environment.…”

“…[5] Moreover, the presence of antibiotics and their transformation products in the environment induces the development of antibiotic-resistant bacteria and genes, which pose serious risk to both human and animal health. [6] Without any doubts, there is an urgent need for the development of effective treatment methods to remove such pollutants from the environment.…”