Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Feb 12;27(3):109192.
doi: 10.1016/j.isci.2024.109192. eCollection 2024 Mar 15.

Photoelectrocatalytic degradation of high-density polyethylene microplastics on TiO2-modified boron-doped diamond photoanode

Wendy Quilumbaquin  1 , G Xavier Castillo-Cabrera  1 , Luis J Borrero-González  2 , José R Mora  3 , Vladimir Valle  4 , Alexis Debut  5 , Luis D Loor-Urgilés  1 , Patricio J Espinoza-Montero  1
Affiliations

Photoelectrocatalytic degradation of high-density polyethylene microplastics on TiO2-modified boron-doped diamond photoanode

Wendy Quilumbaquin et al. iScience. .

Abstract

Microplastic (MP) accumulation in the environment is accelerating rapidly, which has led to their effects on both the ecosystem and human life garnering much attention. This study is the first to examine the degradation of high-density polyethylene (HDPE) MPs via photoelectrocatalysis (PEC) using a TiO2-modified boron-doped diamond (BDD/TiO2) photoanode. This study was divided into three stages: (i) preparation of the photoanode through electrophoretic deposition of synthetic TiO2 nanoparticles on a BDD electrode; (ii) characterization of the modified photoanode using electrochemical, structural, and optical techniques; and (iii) degradation of HDPE MPs by electrochemical oxidation and photoelectrocatalysis on bare and modified BDD electrodes under dark and UV light conditions. The results indicate that the PEC technique degraded 89.91 ± 0.08% of HDPE MPs in a 10-h reaction and was more efficient at a lower current density (6.89 mA cm-1) with the BDD/TiO2 photoanode compared to electrochemical oxidation on bare BDD.

Keywords: Devices; Materials chemistry.

PubMed Disclaimer

Conflict of interest statement

The authors declare no competing interests.

Figures

None
Graphical abstract
Figure 1
Figure 1
Characterization of BDD/TiO2 structure and morphology (A) X-Ray diffraction pattern of (a) BDD/TiO2 photoanode, (b) TiO2 anatase phase and (c) bare BDD. (B) EDS spectrum and elemental mapping of BDD/TiO2 photoanode. (C–E) Scanning electron microscopy images of (C) TiO2 anatase phase, (D) bare BDD electrode, and (E) BDD/TiO2 photoanode.
Figure 2
Figure 2
Electrochemical and photoelectrochemical characterization of BDD/TiO2 (A and B) Cyclic voltammetry (CV) in (A) 4.0 mmol·L-1 [Fe(CN)6]3-/4- in 1.0 mol·L-1 KCl, (B) 0.1 M mol·L-1 Na2SO4, (inset of Tafel plot). (C) Photocurrent response in 0.1 M mol·L-1 Na2SO4. (D) Nyquist plot of bare BDD and BDD/TiO2 photoanode. (E and F) Mott-Schottky plot for (E) bare BDD and (F) BDD/TiO2 photoanode.
Figure 3
Figure 3
Optical analysis of BDD/TiO2 photoanode (A and B) Band gap and UV-vis diffuse reflectance spectra (insets) of (A) BDD/TiO2 and (B) bare BDD.
Figure 4
Figure 4
Performance degradation of high-density polyethylene microplastics on BDD/TiO2 (A) FTIR spectra of HDPE-MPs before and after 10 h reaction by EO using bare BDD and PEC using BDD/TiO2 photoanode. (B and C) Magnified spectra of HDPE-MPs after PEC treatment.
Figure 5
Figure 5
SEM images of high-density polyethylene microplastics at different scales (A) Before treatments. (B) After electrochemical oxidation (10 h reaction). (C) After photoelectrocatalysis (10 h reaction).
Figure 6
Figure 6
Analysis of the filtered solution of the samples treated at different current densities (A) Total organic carbon obtained (TOC). (B) Chemical oxygen demand (COD).
Figure 8
Figure 8
Proposed mechanism of degradation of high-density polyethylene microplastics by photoelectrocatalysis Values above the arrows are the free energy change of each case in kcal·mol-1.
Figure 7
Figure 7
Analysis of •OH generation in the absence and presence of HDPE MPs (A) •OH at different current densities in absence of high-density polyethylene microplastics (HDPE MPs). (B) First-order reaction kinetics analysis of RNO (0.1 mol⋅L-1 Na2SO4). (C) Effect of the presence of HDPE MPs and Tween 20 on the production of •OH. Data are represented as mean ± SEM.
See this image and copyright information in PMC

References

    1. Mu Y., Sun J., Li Z., Zhang W., Liu Z., Li C., Peng C., Cui G., Shao H., Du Z. Activation of pyroptosis and ferroptosis is involved in the hepatotoxicity induced by polystyrene microplastics in mice. Chemosphere. 2022;291 doi: 10.1016/j.chemosphere.2021.132944. - DOI - PubMed
    1. Tanaka K., Takada H. Microplastic fragments and microbeads in digestive tracts of planktivorous fish from urban coastal waters. Sci. Rep. 2016;6 doi: 10.1038/srep34351. - DOI - PMC - PubMed
    1. Naik R.A., Rowles L.S., Hossain A.I., Yen M., Aldossary R.M., Apul O.G., Conkle J., Saleh N.B. Microplastic particle versus fiber generation during photo-transformation in simulated seawater. Sci. Total Environ. 2020;736 doi: 10.1016/j.scitotenv.2020.139690. - DOI - PubMed
    1. Eriksen M., Lebreton L.C.M., Carson H.S., Thiel M., Moore C.J., Borerro J.C., Galgani F., Ryan P.G., Reisser J. Plastic Pollution in the World’s Oceans: More than 5 Trillion Plastic Pieces Weighing over 250,000 Tons Afloat at Sea. PLoS One. 2014;9 doi: 10.1371/journal.pone.0111913. - DOI - PMC - PubMed
    1. Schwarz A.E., Ligthart T.N., Boukris E., van Harmelen T. Sources, transport, and accumulation of different types of plastic litter in aquatic environments: A review study. Mar. Pollut. Bull. 2019;143:92–100. doi: 10.1016/j.marpolbul.2019.04.029. - DOI - PubMed

LinkOut - more resources