Natural Organic Matter Adsorption Conditions Influence Photocatalytic Reaction Pathways of Phosphate-Treated Titanium Dioxide Nanoparticles

2021 ◽  
Author(s):  
Riya A Mathew ◽  
Gang Wu ◽  
Ye Zhang ◽  
Sheyda Shakiba ◽  
Yan Yao ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Water Treatment ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Reaction Pathways ◽  
Photocatalytic Reaction

Titanium dioxide (TiO2) nanoparticles have been widely studied for water treatment applications; however, natural organic matter (NOM) is often reported to hamper the efficiency of the nanoparticles toward the degradation...

scholarly journals DEET Degradation by Titanium Dioxide–Zeolite Nanocomposites: Effects of Aggregation State, Water Chemistry, and Natural Organic Matter

2020 ◽  
Author(s):  
Tchemongo B. Berté ◽  
Anthony S. Chen ◽  
Riya A. Mathew ◽  
Sheyda Shakiba ◽  
Stacey M. Louie
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Water Treatment ◽  
Water Chemistry ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Hard Water ◽  
Aggregation State ◽  
Byproduct Formation ◽  
Partial Dissociation

Immobilization of titanium dioxide nanoparticles (TiO<sub>2</sub> NPs) facilitates their removal and reuse in water treatment applications. Composite materials of electrostatically-bound TiO<sub>2</sub> NPs and zeolite particles have been proposed, but limited mechanistic studies are available on their performance in complex media. This study delineates the relative importance of homo- and heteroaggregation, water chemistry, and surface fouling by natural organic matter (NOM) on the photocatalytic degradation of diethyltoluamide (DEET) by TiO<sub>2</sub>-zeolite composites. Zeolite adsorbs a portion of the DEET, rendering it unavailable for degradation; corrections for this adsorption depletion allowed appropriate comparison of the reactivity of the composites to the NPs alone. The TiO<sub>2</sub>-zeolite composites showed enhanced DEET degradation in moderately hard water (MHW) compared to deionized water (DIW), likely attributable to the influence of HCO<sub>3</sub><sup>−</sup>, whereas a net decline in reactivity was observed for the TiO<sub>2</sub> NPs alone upon homoaggregation in MHW. The composites also better maintained reactivity in the presence of NOM in MHW, as removal of Ca<sup>2+</sup> onto the zeolite mitigated fouling of the TiO<sub>2</sub> surface by NOM. However, NOM induced partial dissociation of the composites. DEET byproduct formation, identified by quadrupole–time of flight (QTOF) mass spectrometry, was generally unaffected by the zeolite, while NOM fouling favored de-ethylation over hydroxylation products. Overall, the most significant factor influencing TiO<sub>2</sub> reactivity toward DEET was NOM adsorption, followed by homoaggregation, electrolytes (here, MHW versus DIW), and heteroaggregation. These findings can inform a better understanding of NP reactivity in engineered water treatment applications.

scholarly journals DEET Degradation by Titanium Dioxide–Zeolite Nanocomposites: Effects of Aggregation State, Water Chemistry, and Natural Organic Matter

2020 ◽  
Author(s):  
Tchemongo B. Berté ◽  
Anthony S. Chen ◽  
Riya A. Mathew ◽  
Sheyda Shakiba ◽  
Stacey M. Louie
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Water Treatment ◽  
Water Chemistry ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Hard Water ◽  
Aggregation State ◽  
Byproduct Formation ◽  
Partial Dissociation

Immobilization of titanium dioxide nanoparticles (TiO<sub>2</sub> NPs) facilitates their removal and reuse in water treatment applications. Composite materials of electrostatically-bound TiO<sub>2</sub> NPs and zeolite particles have been proposed, but limited mechanistic studies are available on their performance in complex media. This study delineates the relative importance of homo- and heteroaggregation, water chemistry, and surface fouling by natural organic matter (NOM) on the photocatalytic degradation of diethyltoluamide (DEET) by TiO<sub>2</sub>-zeolite composites. Zeolite adsorbs a portion of the DEET, rendering it unavailable for degradation; corrections for this adsorption depletion allowed appropriate comparison of the reactivity of the composites to the NPs alone. The TiO<sub>2</sub>-zeolite composites showed enhanced DEET degradation in moderately hard water (MHW) compared to deionized water (DIW), likely attributable to the influence of HCO<sub>3</sub><sup>−</sup>, whereas a net decline in reactivity was observed for the TiO<sub>2</sub> NPs alone upon homoaggregation in MHW. The composites also better maintained reactivity in the presence of NOM in MHW, as removal of Ca<sup>2+</sup> onto the zeolite mitigated fouling of the TiO<sub>2</sub> surface by NOM. However, NOM induced partial dissociation of the composites. DEET byproduct formation, identified by quadrupole–time of flight (QTOF) mass spectrometry, was generally unaffected by the zeolite, while NOM fouling favored de-ethylation over hydroxylation products. Overall, the most significant factor influencing TiO<sub>2</sub> reactivity toward DEET was NOM adsorption, followed by homoaggregation, electrolytes (here, MHW versus DIW), and heteroaggregation. These findings can inform a better understanding of NP reactivity in engineered water treatment applications.

scholarly journals Reduction of Pesticide Toxicity Under Field‐Relevant Conditions? The Interaction of Titanium Dioxide Nanoparticles, Ultraviolet, and Natural Organic Matter

2020 ◽  
Vol 39 (11) ◽  
pp. 2237-2246
Author(s):  
Simon Lüderwald ◽  
Frederik Meyer ◽  
Verena Gerstle ◽  
Lisa Friedrichs ◽  
Katrin Rolfing ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Pesticide Toxicity

scholarly journals Quantity and quality of natural organic matter influence the ecotoxicity of titanium dioxide nanoparticles

2016 ◽  
Vol 10 (10) ◽  
pp. 1415-1421 ◽  
Author(s):  
Frank Seitz ◽  
Ricki R. Rosenfeldt ◽  
Marie Müller ◽  
Simon Lüderwald ◽  
Ralf Schulz ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles

Effect of natural organic matter on the photo-induced toxicity of titanium dioxide nanoparticles

2017 ◽  
Vol 36 (6) ◽  
pp. 1661-1666 ◽  
Author(s):  
Alexis M. Wormington ◽  
Jason Coral ◽  
Matthew M. Alloy ◽  
Carmen L. Delmarè ◽  
Charles M. Mansfield ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles

Impact of natural organic matter on particle behavior and phototoxicity of titanium dioxide nanoparticles

2016 ◽  
Vol 542 ◽  
pp. 324-333 ◽  
Author(s):  
Shibin Li ◽  
Hongbo Ma ◽  
Lindsay K. Wallis ◽  
Matthew A. Etterson ◽  
Benjamin Riley ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Organic Matter ◽  
Natural Organic Matter ◽  
Titanium Dioxide Nanoparticles ◽  
Particle Behavior
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