Influence of pH and pH adjustment conditions on photocatalytic oxidation of aqueous ammonia under airflow over Pt-loaded TiO2

Shibuya, Satoshi; Sekine, Yoshika; Mikami, Ikko

doi:10.1016/j.apcata.2015.02.024

Cited by 28 publications

(19 citation statements)

References 12 publications

(19 reference statements)

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“…Moreover, the space steric hindrance of NH 3 is smaller than the one of

, which is more conducive to the reaction of NH 3 with ·OH (Luo et al, 2015 ). This finding is aligned with the theoretical relationship between pH and ammonia photocatalysis (Wang et al, 2014 ; Shibuya et al, 2015 ).…”

Section: Resultssupporting

confidence: 89%

“…pH is an vital parameter in photocatalytic reactions (Shibuya et al, 2015 ). For the investigation of the photocatalytic

-N removal with Cu/ZnO/rGO at various pH (4.0 to11.0), the catalyst and the ammonia solution were kept in dark for 30 min then excited under light illumination for 2 h. The decrease of

-N in the dark was less than 10%, and the reduction related to the physicochemical adsorption property of the photocalysts.…”

Section: Resultsmentioning

confidence: 99%

“…The

-N removal efficiency increased as per pH rising and reached the maximum at a pH >10. This is explained by the fact that pH influences not only the existing forms of the

-N in solution but also the photocatalyst's surface charge properties (Shibuya et al, 2015 ). Firstly, ionized ammonium (

) and un-ionized ammonia (NH 3 ) are the main types of ammonia nitrogen (at equilibrium in water with a pKa of 9.26).…”

Section: Resultsmentioning

confidence: 99%

See 2 more Smart Citations

High Efficient Visible-Light Photocatalytic Performance of Cu/ZnO/rGO Nanocomposite for Decomposing of Aqueous Ammonia and Treatment of Domestic Wastewater

Hou

Petropoulos

et al. 2018

Front. Chem.

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Photocatalytic removal of ammonium-nitrogen (NH4+-N) from water using solar energy is an approach of high interest and applicability due to the convenience in application. ZnO has a great potential in photocatalytic decomposition of NH4+-N and conversion of this nutrient to under visible light irradiations. However the applicability of pristine ZnO though is limited due to its reduced capacity to utilize light from natural light. Herein, we report a two-step ZnO-modified strategy (Cu-doped ZnO nanoparticles, immobilized on reduced graphene oxide (rGO) sheets) for the promotion of photocatalytic degradation of NH4+-N under visible light. UV-Vis spectra showed that the Cu/ZnO/rGO can be highly efficient in the utilization of photons from the visible region. Hence, Cu/ZnO/rGO managed to demonstrate adequate photocatalytic activity and effective NH4+-N removal from water under visible light compared to single ZnO. Specifically, up to 83.1% of NH4+-N (initial concentration 50 mg·L−1, catalyst dosage 2 g·L−1, pH 10) was removed within 2 h retention time under Xe lamp irradiation. From the catalysis, the major by-product was N2. The high ammonia degradation efficiency from the ZnO/Cu/rGO is attributed to the improvement of the reactive oxygen species (ROSs) production efficiency and the further activation of the interfacial catalytic sites. This study also demonstrated that such nanocomposite is a recyclable agent. Its NH4+-N removal capacity remained effective even after five batch cycles. In addition, Cu/ZnO/rGO was applied to treat real domestic wastewater, and it was found that chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) removal efficiencies can reach 84.3, 80.7, and 90.3%, respectively. Thus, Cu/ZnO/rGO in the presence of solar light can be a promising photocatalyst in the field of wastewater treatment.

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“…Moreover, the space steric hindrance of NH 3 is smaller than the one of

Section: Resultssupporting

confidence: 89%

“…pH is an vital parameter in photocatalytic reactions (Shibuya et al, 2015 ). For the investigation of the photocatalytic

-N removal with Cu/ZnO/rGO at various pH (4.0 to11.0), the catalyst and the ammonia solution were kept in dark for 30 min then excited under light illumination for 2 h. The decrease of

-N in the dark was less than 10%, and the reduction related to the physicochemical adsorption property of the photocalysts.…”

Section: Resultsmentioning

confidence: 99%

“…The

-N removal efficiency increased as per pH rising and reached the maximum at a pH >10. This is explained by the fact that pH influences not only the existing forms of the

-N in solution but also the photocatalyst's surface charge properties (Shibuya et al, 2015 ). Firstly, ionized ammonium (

) and un-ionized ammonia (NH 3 ) are the main types of ammonia nitrogen (at equilibrium in water with a pKa of 9.26).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

High Efficient Visible-Light Photocatalytic Performance of Cu/ZnO/rGO Nanocomposite for Decomposing of Aqueous Ammonia and Treatment of Domestic Wastewater

Hou

Petropoulos

et al. 2018

Front. Chem.

View full text Add to dashboard Cite

show abstract

“…Many researchers have discussed the effect of acidic or alkaline pHs on the photocatalytic activity of TiO 2 nanoparticles [ 1 , 9 , 24 ]. However, the effect of acidic pH on the photoluminescence features of anatase TiO 2 nanoparticles has been relatively unexplored [10] .…”

Section: Introductionmentioning

confidence: 99%

Influence of acidic pH on the formulation of TiO 2 nanocrystalline powders with enhanced photoluminescence property

Tsega

Dejene

2017

Heliyon

103

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Titanium dioxide (TiO2) nanoparticles were prepared by the sol-gel method at different pH values (3.2–6.8) with a hydrochloric acid (HCl) solution. Raw samples were calcined at 500 °C for 2 h. The effects of pH on the structural, morphological and optical properties of TiO2 nanoparticles were investigated. At pH 4.4–6.8, only the anatase phase of TiO2 was observed. Under strong acidic condition at pH 3.2 rutile, brookite and anatase co-exist, but rutile is the predominant phase. The strain value increased and the crystallite size decreased as the HCl content increased. The increased crystallite sizes in the range 21–24 nm and enhanced blue emission intensity around 432 nm was obtained for the sample at pH 5.0. Experimental results showed that TiO2 nanoparticles synthesized at pH 5.0 exhibited the best luminescence property with pure anatase phase.

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“…51,52 Many studies have proved the importance of solution pH as one of the critical control parameters in the adsorption process, especially in ammonia adsorption. [53][54][55][56] The solution pH had an important inuence on the equilibrium ammonia concentration and the ammonia removal efficiency. The effect of solution pH on the ammonia adsorption on AMAR were shown in Fig.…”

Section: Effect Of Phmentioning

confidence: 99%

Removal of ammonia from aqueous solutions by ligand exchange onto a Cu(ii)-loaded chelating resin: kinetics, equilibrium and thermodynamics

Chen

Wang

et al. 2017

RSC Adv.

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Influence of pH and pH adjustment conditions on photocatalytic oxidation of aqueous ammonia under airflow over Pt-loaded TiO2

Cited by 28 publications

References 12 publications

High Efficient Visible-Light Photocatalytic Performance of Cu/ZnO/rGO Nanocomposite for Decomposing of Aqueous Ammonia and Treatment of Domestic Wastewater

High Efficient Visible-Light Photocatalytic Performance of Cu/ZnO/rGO Nanocomposite for Decomposing of Aqueous Ammonia and Treatment of Domestic Wastewater

Influence of acidic pH on the formulation of TiO 2 nanocrystalline powders with enhanced photoluminescence property

Removal of ammonia from aqueous solutions by ligand exchange onto a Cu(ii)-loaded chelating resin: kinetics, equilibrium and thermodynamics

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