“…One notable observation was the drastic reduction in the amount of the methylene blue dye after the 30 minutes of stirring in the dark to attain adsorption-desorption equilibrium. Our previous studies concluded that clay samples easily adsorb methylene blue than rhodamine b dye due to the difference in molecular structure and ionic charge characteristics of these two dyes [49].Fig. 8(a) Photodegradation of methylene blue by Ag 2 CO 3 and Ag 2 CO 3 -25 wt.% HNTs, (b) Calculated pseudo first order rate constants and removal efficiencies by Ag 2 CO 3 and Ag 2 CO 3 -25 wt.% HNTs.…”
The release of water soluble dyes into the environment is an utmost concern in many countries. This paper presents the effects of Ag
2
CO
3
-halloysite composites on the efficient removal of water soluble dyes. In this study, NaHCO
3
solution was added dropwisely to halloysite nanotubes (HNTs) dispersed in aqueous AgNO
3
to form Ag
2
CO
3
-HNTs composite. The synthesized Ag
2
CO
3
-HNTs composite was characterized with Diffused Reflectance Spectroscopy (DRS), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX) and Fourier Transform Infra-Red (FT-IR) spectroscopy. The photocatalytic activity and the adsorption capacity of Ag
2
CO
3
-HNTs on methylene blue and rhodamine b dyes were dependent on pH and the amount of HNTs used in the synthesis. The photodegradation efficiency of Ag
2
CO
3
was lower when compared with that of the composite material. This observation is due to the reduction in the electron-hole recombination with the HNTs acting as electron trapping site and the enhanced aqueous dispersity of Ag
2
CO
3
-HNTs. The enhanced adsorption of water soluble dyes by the Ag
2
CO
3
-HNTs resulted from the electrostatic attraction of cationic dyes to the surface of the HNTs (negatively charged). The Ag
2
CO
3
-HNTs therefore removed dye pollutants through a combination of photocatalytic and adsorption processes. The results obtained during the study confirmed the potential application of Ag
2
CO
3
-HNTs composite in water treatment technologies.
“…One notable observation was the drastic reduction in the amount of the methylene blue dye after the 30 minutes of stirring in the dark to attain adsorption-desorption equilibrium. Our previous studies concluded that clay samples easily adsorb methylene blue than rhodamine b dye due to the difference in molecular structure and ionic charge characteristics of these two dyes [49].Fig. 8(a) Photodegradation of methylene blue by Ag 2 CO 3 and Ag 2 CO 3 -25 wt.% HNTs, (b) Calculated pseudo first order rate constants and removal efficiencies by Ag 2 CO 3 and Ag 2 CO 3 -25 wt.% HNTs.…”
The release of water soluble dyes into the environment is an utmost concern in many countries. This paper presents the effects of Ag
2
CO
3
-halloysite composites on the efficient removal of water soluble dyes. In this study, NaHCO
3
solution was added dropwisely to halloysite nanotubes (HNTs) dispersed in aqueous AgNO
3
to form Ag
2
CO
3
-HNTs composite. The synthesized Ag
2
CO
3
-HNTs composite was characterized with Diffused Reflectance Spectroscopy (DRS), X-ray Diffraction (XRD), Thermogravimetric analysis (TGA), Scanning Electron Microscopy-Energy Dispersive Spectroscopy (SEM-EDX) and Fourier Transform Infra-Red (FT-IR) spectroscopy. The photocatalytic activity and the adsorption capacity of Ag
2
CO
3
-HNTs on methylene blue and rhodamine b dyes were dependent on pH and the amount of HNTs used in the synthesis. The photodegradation efficiency of Ag
2
CO
3
was lower when compared with that of the composite material. This observation is due to the reduction in the electron-hole recombination with the HNTs acting as electron trapping site and the enhanced aqueous dispersity of Ag
2
CO
3
-HNTs. The enhanced adsorption of water soluble dyes by the Ag
2
CO
3
-HNTs resulted from the electrostatic attraction of cationic dyes to the surface of the HNTs (negatively charged). The Ag
2
CO
3
-HNTs therefore removed dye pollutants through a combination of photocatalytic and adsorption processes. The results obtained during the study confirmed the potential application of Ag
2
CO
3
-HNTs composite in water treatment technologies.
“…is was followed by oven-drying at a temperature of 70°C. e samples were later powdered for characterization [32].…”
Section: Synthesis Of Zeolitesmentioning
confidence: 99%
“…e batch adsorption experiment was generally carried out using an adsorbent loading of 2.8 mg, at pH of 9 and at a room temperature of 25°C. During the experiment, 3.5 mL of 2 mg/L concentration of methylene blue (MB) aqueous solution was added to 2.8 mg of zeolite/magnetite nanocomposite in a cuvette, and the absorbance was collected over a period of 3 hours [32]. is procedure was repeated using 4, 6, 8, and 10 mg/L concentrations of MB to study the effect of dye concentration on equilibrium.…”
Section: Adsorption Experimentsmentioning
confidence: 99%
“…Zeolite, an aluminosilicate material, has well-defined molecular-sized pores [31] ese cations are exchangeable in solution through ionic exchange [31,32]. Research has shown that the porous framework of zeolite has good adsorption efficiency in the removal of heavy metals like arsenic, mercury, fluoride, and organic dyes and as a host material in catalytic applications [4,5,16,33].…”
In this work, zeolite (Z) and Z-Fe3O4 nanocomposite (Z-Fe3O4 NC) have been synthesized. The Fe3O4 nanoparticles were synthesized using the extract from maize leaves and ferric and ferrous chloride salts and encapsulated into the zeolite framework. The nanocomposite (Z-Fe3O4 NC) was characterized using X-ray diffractometer (XRD), Fourier-transform infrared (FT-IR) spectroscopy, energy-dispersive X-ray (EDX) spectroscopy, and scanning electron microscopy (SEM). The potential of Z-Fe3O4 NC as an adsorbent for removing methylene blue molecules (MB) from solution was examined using UV-Vis and kinetic and equilibrium isotherm models. The adsorption data fitted best with the pseudo-second-order model and Weber and Morris model, indicating that the adsorption process was chemisorption, while the Weber and Morris described the rate-controlling steps. The intraparticle diffusion model suggests that the adsorption processes were pore and surface diffusion controlled. The Langmuir isotherm model best describes the adsorption process indicating homogeneous monolayer coverage of MB molecules onto the surface of the Z-Fe3O4 NC. The maximum Langmuir adsorption capacity was 2.57 mg/g at 25°C. The maximum adsorption efficiency was 97.5%. After regeneration, the maximum adsorption efficiency achieved at a pH of 7 was 82.6%.
“…Clay materials including HNTs have been reported to be poor adsorbents of rhodamine B dyes. is has been ascribed to the molecular size of rhodamine B and the nature of the interaction between rhodamine dyes and clays [40]. e lower adsorption of rhodamine B ensured that the TiO 2 surface was not completely covered by the pollutants, and this allowed for enhanced absorption of photons.…”
Section: Adsorption and Photocatalysis Of Tio 2 And Tio 2 -Fe-hntmentioning
In this work, the potential application of TiO 2 -Fe-HNT photocatalyst-adsorbent composite in water treatment technologies was confirmed. e photocatalyst-adsorbent composite (TiO 2 -Fe-HNTs) was synthesized by the hydrothermal method and characterized by X-ray diffraction, thermogravimetric analysis, Fourier-transform infrared spectroscopy, scanning electron microscopy-energy dispersive X-ray spectroscopy, and diffuse reflectance spectroscopy. e adsorption and photocatalysis mechanism by the TiO 2 -Fe-HNT composite were examined on methylene blue dye, rhodamine blue dye, naproxen sodium (pharmaceutical drug waste), and imidacloprid (pesticide). e TiO 2 -Fe-HNT composite was active in UV and visible regions of the electromagnetic spectrum. e adsorption and photocatalytic efficiency increased with increasing amount of HNTs. e photocatalyst-adsorbent composite exhibited excellent removal efficiency for pharmaceutical waste (naproxen sodium) and pesticides (imidacloprid). An adsorption equilibrium data fitted well with the pseudo-second-order kinetics for both methylene blue and rhodamine blue dyes with the intraparticle model describing its rate-controlling steps. e Langmuir and Freundlich isotherm models further described the adsorption of methylene blue and rhodamine blue molecules, respectively.
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