Degradation of the pharmaceuticals lamivudine and zidovudine using advanced oxidation processes

The existence of pharmaceuticals in nature is a growing environmental problem, turning necessary the use of efficient treatments for the degradation of these substances, as the advanced oxidation processes (AOPs). In this work the AOPs UV/H2O2 and photo-Fenton were applied to degrade the pharmaceuticals lamivudine and zidovudine in an aqueous solution using a bench reactor, composed of three UV-C lamps. It was verified that the UV/H2O2 process presented a degradation of 97.33 ± 0.14% for lamivudine and 93.90 ± 0.33% for zidovudine, after 180 min of treatment and for an initial concentratin of each pharmaceutical of 5 mg.L-1 and [H2O2] of 600 mg.L-1. A methodology by artificial neural networks (ANNs) was used to model the photocatalytic process, with the MLP 7-23-2 ANN representing it well, and determining the relative importance (%) of each of the input variables for the pharmaceutical’s degradation process. Kinetic studies for the pharmaceutical degradation and the conversion of organic matter showed good adjustments to the pseudo first-order models with R2 raging from 0.9705 to 0.9980. Toxicity assays for the before treatment solution indicated that the seeds Lactuca sativa and Portulaca grandiflora showed growth inhibition whereas the post-treatment solution inhibited only the growth of Lactuca sativa.

Degradation of the pharmaceuticals lamivudine and zidovudine using advanced oxidation processes

The existence of pharmaceuticals in nature is a growing environmental problem, turning necessary the use of efficient treatments for the degradation of these substances, as the advanced oxidation processes (AOPs). In this work the AOPs UV/H2O2 and photo-Fenton were applied to degrade the pharmaceuticals lamivudine and zidovudine in an aqueous solution using a bench reactor, composed of three UV-C lamps. It was verified that the UV/H2O2 process presented a degradation of 97.33 ± 0.14% for lamivudine and 93.90 ± 0.33% for zidovudine, after 180 min of treatment and for an initial concentratin of each pharmaceutical of 5 mg.L-1 and [H2O2] of 600 mg.L-1. A methodology by artificial neural networks (ANNs) was used to model the photocatalytic process, with the MLP 7-23-2 ANN representing it well, and determining the relative importance (%) of each of the input variables for the pharmaceutical’s degradation process. Kinetic studies for the pharmaceutical degradation and the conversion of organic matter showed good adjustments to the pseudo first-order models with R2 raging from 0.9705 to 0.9980. Toxicity assays for the before treatment solution indicated that the seeds Lactuca sativa and Portulaca grandiflora showed growth inhibition whereas the post-treatment solution inhibited only the growth of Lactuca sativa.

Degradation of acetaminophen (ACT) by ozone/persulfate oxidation process: experimental and degradation pathways

Purpose The purpose of this study to investigate acetaminophen (ACT) degradation efficiencies by using ozone/persulfate oxidation process in a batch reactor. In addition, the effects of various parameters on the ACT removal efficiency toward pathway inference of ACT degradation were investigated. Design/methodology/approach The experiments were in the 2 L glass vessels. Ozone gas with flow rate at 70 L.h−1 was produced by ozone generator. After the adjustment of the pH, various dosages of persulfate (1, 3, 5, 7 and 9 mmol.L−1) were then added to the 500 mL ACT-containing solution with 150 mg.L−1 of concentration. Afterward, ozone gas was diffused in glass vessels. The solution after reaction flowed into the storage tank for the detection. The investigated parameters included pH and the amount of ozone and persulfate addition. For comparison of the ACT degradation efficiency, ozone/persulfate, ozone and persulfate oxidation in reactor was carried out. The ACT concentration using a HPLC system equipped with 2998 PDA detector was determined at an absorbance of 242 nm. Findings ACT degradation percentage by using ozone or persulfate in the process were at 63.7% and 22.3%, respectively, whereas O3/persulfate oxidation process achieved degradation percentage at 91.4% in 30 min. Degradation efficiency of ACT was affected by different parameter like pH and addition of ozone or persulfate, and highest degradation obtained when pH and concentrations of persulfate and ozone was 10 and 3 mmol.L−1 and 60 mg.L−1, respectively. O3, OH• and SO4− were evidenced to be the radicals for degradation of ACT through direct and indirect oxidation. Gas chromatography–mass spectrometer analysis showed intermediates including N-(3,4-dihydroxyphenyl) formamide, hydroquinone, benzoic acid, 4-methylbenzene-1,2-diol, 4-aminophenol. Practical implications This study provided a simple and effective way for degradation of activated ACT as emerging contaminants from aqueous solution. This way was conducted to protect environment from one of the most important and abundant pharmaceutical and personal care product in aquatic environments. Originality/value There are two main innovations. One is that the novel process is performed successfully for pharmaceutical degradation. The other is that the optimized conditions are obtained. In addition, the effects of various parameters on the ACT removal efficiency toward pathway inference of ACT degradation were investigated.

Unveiling of Concealed Processes for the Degradation of Pharmaceutical Compounds by Neopestalotiopsis sp.

The presence of pharmaceutical products has raised emerging biorisks in aquatic environments. Fungi have been considered in sustainable approaches for the degradation of pharmaceutical compounds from aquatic environments. Soft rot fungi of the Ascomycota phylum are the most widely distributed among fungi, but their ability to biodegrade pharmaceuticals has not been studied as much as that of white rot fungi of the Basidiomycota phylum. Herein, we evaluated the capacity of the soft rot fungus Neopestalotiopsis sp. B2B to degrade pharmaceuticals under treatment of woody and nonwoody lignocellulosic biomasses. Nonwoody rice straw induced laccase activity fivefold compared with that in YSM medium containing polysaccharide. But B2B preferentially degraded polysaccharide over lignin regions in woody sources, leading to high concentrations of sugar. Hence, intermediate products from saccharification may inhibit laccase activity and thereby halt the biodegradation of pharmaceutical compounds. These results provide fundamental insights into the unique characteristics of pharmaceutical degradation by soft rot fungus Neopestalotiopsis sp. in the presence of preferred substrates during delignification.

Enhanced visible light photocatalysis by TiO2–BN enabled electrospinning of nanofibers for pharmaceutical degradation and wastewater treatment

Electrospun TiO2–BN nanofibers were characterized to understand surface chemistry and elucidate mechanisms for degradation of organic contaminants in wastewater.