TY - JOUR

T1 - A comparative study of microcystin-LR degradation by UV-a, solar and visible light irradiation using bare and C/N/S-modified titania

AU - Khedr, Tamer M.

AU - El-Sheikh, Said M.

AU - Abdeldayem, Hany M.

AU - Ismail, Adel A.

AU - Kowalska, Ewa

AU - Bahnemann, Detlef W.

N1 - Funding information: This work was supported by the Egyptian Ministry of Higher Education (Cultural Affairs and Missions Sector). A part of this work was also supported by the US–Egypt Joint project Cycle 17 No. 229 and short-term fellowship Cycle 6, Science & Technological Development Fund in Egypt (STDF-STF) under Grant No. 25503.

PY - 2019/11

Y1 - 2019/11

N2 - In an endeavor to tackle environmental problems, the photodegradation of microcystin- LR (MC-LR), one of the most common and toxic cyanotoxins, produced by the cyanobacteria blooms, was examined using nanostructured TiO2 photocatalysts (anatase, brookite, anatase- brookite, and C/N/S co-modified anatase-brookite) under UV-A, solar and visible light irradiation. The tailoring of TiO2 properties to hinder the electron-hole recombination and improve MC-LR adsorption on TiO2 surface was achieved by altering the preparation pH value. The highest photocatalytic efficiency was 97% and 99% with degradation rate of 0.002 mmol L-1 min-1 and 0.0007 mmol L-1 min-1 under UV and solar irradiation, respectively, using a bare TiO2 photocatalyst prepared at pH 10 with anatase to brookite ratio of ca. 1:2.5. However, the bare TiO2 samples were hardly active under visible light irradiation (<25%) due to a large band gap. Upon UV, solar and vis irradiation, the complete MC-LR degradation (100%) was obtained in the presence of C/N/S comodified TiO2 with a degradation rate constant of 0.26 min-1, 0.11 min-1 and 0.04 min-1, respectively. It was proposed that the remarkable activity of co-modified TiO2 might originate from its mixedphase composition, mesoporous structure, and non-metal co-modification.

AB - In an endeavor to tackle environmental problems, the photodegradation of microcystin- LR (MC-LR), one of the most common and toxic cyanotoxins, produced by the cyanobacteria blooms, was examined using nanostructured TiO2 photocatalysts (anatase, brookite, anatase- brookite, and C/N/S co-modified anatase-brookite) under UV-A, solar and visible light irradiation. The tailoring of TiO2 properties to hinder the electron-hole recombination and improve MC-LR adsorption on TiO2 surface was achieved by altering the preparation pH value. The highest photocatalytic efficiency was 97% and 99% with degradation rate of 0.002 mmol L-1 min-1 and 0.0007 mmol L-1 min-1 under UV and solar irradiation, respectively, using a bare TiO2 photocatalyst prepared at pH 10 with anatase to brookite ratio of ca. 1:2.5. However, the bare TiO2 samples were hardly active under visible light irradiation (<25%) due to a large band gap. Upon UV, solar and vis irradiation, the complete MC-LR degradation (100%) was obtained in the presence of C/N/S comodified TiO2 with a degradation rate constant of 0.26 min-1, 0.11 min-1 and 0.04 min-1, respectively. It was proposed that the remarkable activity of co-modified TiO2 might originate from its mixedphase composition, mesoporous structure, and non-metal co-modification.

KW - Anatase/brookite

KW - Cyanotoxins

KW - Emerging pollutants

KW - Microcystin-LR

KW - Non-metal co-modification

KW - Photodecomposition

UR - http://www.scopus.com/inward/record.url?scp=85075060181&partnerID=8YFLogxK

U2 - 10.3390/catal9110877

DO - 10.3390/catal9110877

M3 - Article

AN - SCOPUS:85075060181

VL - 9

JO - CATALYSTS

JF - CATALYSTS

SN - 2073-4344

IS - 11

M1 - 877

ER -