$TiO_2$-Encapsulated EFAL-Removed Zeolite Y as a New Photocatalyst for Photodegradation of Azo Dyes in Aqueous Solution

조원재,윤숙자,윤민중,ChO, Won-Je,Sook-Ja Yoon,,Yoon, Min-Joong 한국광과학회 2005 Journal of Photosciences Vol.12 No.1

Application of a new photocatalyst has been attempted to improve the efficiency and rates of photocatalytic degradation of azo dyes by using a model dye such as Methyl Orange. As a new photocatalyst, $TiO_2$ encapsulated EFAL-removed zeolite Y ($TiO_2$ /EFAL-removed zeolite Y) has been synthesized by ion-exchange in the mixture of EFAL-removed zeolite Y with 0.05 M aqueous [$(NH_4)_2 TiO(C_2O_4)_2.H_2O$] [$TiO(C_2O_4)_2.H_2O$]. This new photocatalyst has been characterized by measuring XRD, IR and reflectance absorption spectra as well as ICP analysis, and it was found that the framework structure of $TiO_2$ /EFAL-removed zeolite Y is not changed by removing the extra-framework aluminum (EFAL) from the normal zeolite Y and the $TiO_2$ inside the photocatalyst exists in the form of $(TiO^{2+})_n$ nanoclusters. Based on the ICP analysis, the Si/Al ratio of the $TiO_2$ /EFAL-removed zeolite Y and the weight of $TiO_2$ were determined to be 23 and 0.061g in 1.0g photocatalyst, respectively. It was also found that adsorption of the azo dye in the $TiO_2$ /EFAL-removed zeolite is very effective (about 80 % of the substrate used). This efficient adsorption contributes to the synergistic photocatalytic activities of the $TiO_2$ /EFAL-removed zeolite by minimizing the required flux diffusion of the substrate. Thus, the photocatalytic reduction of methyl orange (MO) was found to be 8 times more effective in the presence of $TiO_2$ /EFAL-removed zeolite Y than in the presence of $TiO_2$ /normal zeolite Y. Furthermore, the photocatalytic reduction of MO by using 1.0 g of the $TiO_2$ /EFAL-removed zeolite Y containing 0.061g of $TiO_2$ is much faster than that carried out by using 1.0 g of Degussa P-25.

Facile Fabrication of Quaternary Ammonium Salt Modified Cotton Linter by Radiation Grafting and its Effective Removal of Methyl Orange: Batch and Dynamic Flow Mode Studies

Jifu Du,Manman Zhang,Zhen Dong,Xin Yang,Houhua Xiong,Zhengkui Zeng,Zhiyuan Chen,Long Zhao 한국섬유공학회 2022 Fibers and polymers Vol.23 No.4

Methyl orange plays a vital role in various branches of the dyeing and textile industries and must be treated beforebeing discharged into the environment. In this study, methacryloxyethyltrimethyl ammonium chloride (DMC) functionalizedcotton linter (DMCCL) was prepared using a radiation technique. The prepared DMCCL was then characterized by IR, SEM,TG, and XPS analyses. The results showed that DMC was successfully grafted onto the surface of the cotton linter. Theadsorption performance toward methyl orange (MO) was investigated using batch and fix-bed column experiments. Adsorption kinetic and isotherm studies were well described by pseudo-second-order kinetic and Langmuir isotherm model,respectively. The maximum adsorption capacity for MO was 645.16 mg/g. The fixed-bed column experiment showed thatThomas and Yoon-Nelson models described the experimental data well. The column study showed the adsorption capacityreached 564.46 mg/g with a MO concentration of 25 mg/l and flow rate 1.5 ml/min. The saturated DMCCL column could beregenerated efficiently by eluting with 1 M HCl. Therefore, the DMCCL exhibited excellent adsorption performance, whichis suitable for MO removal from aqueous solution.

The study of thermodynamics and kinetics methyl orange and malachite green by SWCNTs, SWCNT-COOH and SWCNT-NH2 as adsorbents from aqueous solution

Mania Setareh Derakhshan,Omid Moradi 한국공업화학회 2014 Journal of Industrial and Engineering Chemistry Vol.20 No.5

The effective removal of dyes from aqueous wastes is among the most important issues for many industrialized countries. Removal of methyl orange (MO) and malachite green (MG) from aqueous solutions were studied using single-walled carbon nanotubes (SWCNTs), carboxylate functionalized single-walled carbon nanotubes (SWCNT-COOH) and amide functionalized single-walled carbon nanotubes (SWCNT-NH2). The adsorption process was found to be controlled by temperature, ionic strength, initial concentration, adsorbent dosage and contact time. The microstructure of carbon nanotubes was characterized using SEM and FTIR. The adsorbents studied exhibits high efficiency for MO and MG adsorption and the equilibrium states could be achieved in 20, 20, 15 (min) for SWCNTs, SWCNTCOOH, SWCNT-NH2, respectively. Adsorption capacity of each adsorbent increased with increasing active groups on the surface of carbon nanotube, where SWCNT-NH2 was the most effectively adsorbent.

Adsorptive removal of methyl orange and methylene blue from aqueous solution with a metal-organic framework material, iron terephthalate (MOF-235)

Haque, Enamul,Jun, Jong Won,Jhung, Sung Hwa Elsevier 2011 Journal of hazardous materials Vol.185 No.1

<P><B>Abstract</B></P><P>An iron terephthalate (MOF-235), one of the metal-organic frameworks (MOFs), has been used for the removal of harmful dyes (anionic dye methyl orange (MO) and cationic dye methylene blue (MB)) from contaminated water <I>via</I> adsorption. The adsorption capacities of MOF-235 are much higher than those of an activated carbon. The performance of MOF-235 having high adsorption capacity is remarkable because the MOF-235 does not adsorb nitrogen at liquid nitrogen temperature. Based on this study, MOFs, even if they do not adsorb gases, can be suggested as potential adsorbents to remove harmful materials in the liquid phase. Adsorption of MO and MB at various temperatures shows that the adsorption is a spontaneous and endothermic process and that the entropy increases (the driving force of the adsorption) with adsorption of MO and MB.</P>

Au nanoparticles enhanced Z-scheme Au-CoFe₂O₄/MoS₂ visible light photocatalyst with magnetic retrievability

Jia, Yuefa,Ma, Haoxuan,Liu, Chunli Elsevier 2019 APPLIED SURFACE SCIENCE - Vol.463 No.-

<P><B>Abstract</B></P> <P>A novel Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> photocatalytic composite with high, stable, and remarkable visible light activity was prepared via a sol-gel and hydrothermal route. Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> composite show improved properties in BET, UV–vis DRS, and PL characterization as compared to Au-CoFe<SUB>2</SUB>O<SUB>4</SUB> or CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB>. The photocatalytic performance was investigated by the degradation of methyl orange (MO) in aqueous suspension under visible light irradiation. As compared to CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB>, the degradation efficiency of MO was improved by nearly 60% in the Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> composite, which can be attributed to the better electron hole separation over the interface through Au nanoparticles. The existence of Au nanoparticles at the interface between CoFe<SUB>2</SUB>O<SUB>4</SUB> and MoS<SUB>2</SUB> provided a preferred route for the Z-scheme transfer of the charge carriers. Due to the room temperature magnetization of CoFe<SUB>2</SUB>O<SUB>4</SUB>, the photocatalyst composite can be recycled easily and showed very stable efficiency in degradation of MO. The investigation of the degradation mechanism revealed that <SUP> </SUP>O<SUB>2</SUB> <SUP>−</SUP> radicals played the most important role in the photocatalytic reaction, which supported the Z-scheme transfer in the Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> composite.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A new type ternary Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> Z scheme photocatalyst. </LI> <LI> The function of Au in the interphase between CoFe<SUB>2</SUB>O<SUB>4</SUB> and MoS<SUB>2</SUB> was investigated. </LI> <LI> Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> shows superior photocatalytic activity. </LI> <LI> Methyl orange can be removed by Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> under visible light irradiation. </LI> <LI> Cycle degradation tests show the catalyst was highly active, stable and recoverable. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Magnetic separable Au-CoFe<SUB>2</SUB>O<SUB>4</SUB>/MoS<SUB>2</SUB> photocatalyst exhibits an outstanding photocatalytic activity in degradation of methyl orange (MO) under visible light irradiation, due to the much-improved interface conductivity and charge separation capability.</P> <P>[DISPLAY OMISSION]</P>

The relationship between photo-catalytic performance and optical property over Si-incorporated TiO₂

Lee, I.,Jung, T.,Kim, J.,Ro, S.,Kim, C.,Lee, Y.,Kim, Y.,Lee, J.,Kang, M. Korean Society of Industrial and Engineering Chemi 2008 Journal of industrial and engineering chemistry Vol.14 No.6

This study focuses on the relationship between photo-catalytic performance and optical property over Si-incorporated TiO<SUB>2</SUB>. The Si-incorporated TiO<SUB>2</SUB> particles exhibited a pure structure of anatase having a particle size of less than 20nm and surface area of more than 190m<SUP>2</SUP>/g. The absorbance did not shift to a higher wavelength in spite of the incorporation of the Si ions, but the intensity of the photoluminescence (PL) curve was the smallest in the case of the 2.0mol% Si-TiO<SUB>2</SUB>, which was related to the recombination between the excited electrons and holes. Based on these results, the photodecomposition of methyl orange in the liquid reaction was enhanced over the 2.0mol% Si-incorporated TiO<SUB>2</SUB> compared with that over pure TiO<SUB>2</SUB>: Methyl orange at 10.0ppm was completely decomposed after 100min when 1.0g of the 2.0mol% Si-incorporated TiO<SUB>2</SUB> was used.

The relationship between photo-catalytic performance and optical property over Si-incorporated TiO2

이인준,정태성,김정기,노수호,김철수,이예지,김영미,이주현,강미숙 한국공업화학회 2008 Journal of Industrial and Engineering Chemistry Vol.14 No.6

This study focuses on the relationship between photo-catalytic performance and optical property over Si-incorporated TiO2. The Siincorporated TiO2 particles exhibited a pure structure of anatase having a particle size of less than 20 nm and surface area of more than 190 m2/g. The absorbance did not shift to a higher wavelength in spite of the incorporation of the Si ions, but the intensity of the photoluminescence (PL) curve was the smallest in the case of the 2.0 mol% Si-TiO2, which was related to the recombination between the excited electrons and holes. Based on these results, the photodecomposition of methyl orange in the liquid reaction was enhanced over the 2.0 mol% Si-incorporated TiO2 compared with that over pure TiO2: Methyl orange at 10.0 ppm was completely decomposed after 100 min when 1.0 g of the 2.0 mol% Siincorporated TiO2 was used.

Synthesis of Bi2WO6 Nanometer Sheet Shaped and Approach to the Photocatalysis

Dong Young Kim,Sujung Kim,강미숙 대한화학회 2009 Bulletin of the Korean Chemical Society Vol.30 No.3

For use as a photocatalyst, bismuth tungsten oxide, Bi2WO6, was successfully synthesized by hydrothermal treatment at pH = 11 and heating at 200 oC for 24 h, and samples were subsequently thermal treated at 400, 600, and 800 oC to increase crystallinity. TEM results revealed that the initial untreated particles were sheet‐shaped, grain size was below 80 nm, and it increased with treated temperatures. These Bi2WO6 samples absorbed at around 400 nm in the visible light range and the intensity of absorption was particularly strongest in samples thermal treated at 600 oC. Their photoluminescence abilities, related to the recombination between the excited electrons and holes, were overall small for other general photocatalysts such as TiO2, and the smallest in the case of thermal treatment at 600 oC, as reversible result of UV‐visible absorbance. Methyl orange of 5.0 ppm aqueous solution was almost completely removed after 2 h when treated over the Bi2WO6 thermal treated at 600 oC.

Synthesis of Bi₂WO₆ Nanometer Sheet Shaped and Approach to the Photocatalysis

Kim, Dong-Young,Kim, Su-Jung,Kang, Mi-Sook Korean Chemical Society 2009 Bulletin of the Korean Chemical Society Vol.30 No.3

For use as a photocatalyst, bismuth tungsten oxide, $Bi_2WO_6$, was successfully synthesized by hydrothermal treatment at pH = 11 and heating at 200 ${^{\circ}C}$ for 24h, and samples were subsequently thermal treated at 400, 600, and 800 ${^{\circ}C}$ to increase crystallinity. TEM results revealed that the initial untreated particles were sheet‐shaped, grain size was below 80 nm, and it increased with treated temperatures. These $Bi_2WO_6$ samples absorbed at around 400 nm in the visible light range and the intensity of absorption was particularly strongest in samples thermal treated at 600 ${^{\circ}C}$. Their photoluminescence abilities, related to the recombination between the excited electrons and holes, were overall small for other general photocatalysts such as TiO2, and the smallest in the case of thermal treatment at 600 ${^{\circ}C}$, as reversible result of UV‐visible absorbance. Methyl orange of 5.0 ppm aqueous solution was almost completely removed after 2 h when treated over the $Bi_2WO_6$ thermal treated at 600 ${^{\circ}C}$.