Rajni Lasyal; Shakunj Rajput
Abstract
In this study, the degradation of azo-dye acid orange 10 has been investigated using Polyvinylpyrrolidone and Brij-35 stabilized iridium oxide nanoclusters as catalysts. Simple chemical reduction method was used to synthesize the above-mentioned nanoclusters. The characteristics of the nanocatalysts ...
Read More
In this study, the degradation of azo-dye acid orange 10 has been investigated using Polyvinylpyrrolidone and Brij-35 stabilized iridium oxide nanoclusters as catalysts. Simple chemical reduction method was used to synthesize the above-mentioned nanoclusters. The characteristics of the nanocatalysts were determined by UV-visible spectrophotometer, TEM and XRD. The kinetic study has been carried out at λmax of reaction mixture i.e. 479 nm spectrophotometrically. The degradation follows first order kinetics with respect to oxidant and catalyst concentration while order is one at lower substrate concentration tending towards zero at higher concentration. The degradation kinetics has been supported by the derived rate law. The results showed that Polyvinylpyrrolidone stabilized iridium oxide nanoclusters outperformed Brij-35 stabilized iridium oxide nanoclusters, exhibiting the fastest degradation rate. The progress of the degradation process was monitored by UV-vis spectroscopy. Using Polyvinylpyrrolidone stabilized iridium oxide nanoclusters as a catalyst is a very promising approach for the remediation of acid orange 10 due to the fast degradation rate and high degradation efficiency. In addition, Polyvinylpyrrolidone stabilized iridium oxide nanoclusters can be easily recovered and recycled for three consecutive cycles. It can be inferred from this study that catalytic oxidation methods are active and environment-friendly for the remediation of dyes.
Mona Nabizad; Ahmad Dadvand Koohi; Zahra Erfanipour
Abstract
In this study, alginate, magnetite, and hydroxyapatite were used to fabricate alginate-hydroxyapatite (Alg-Hap), alginate-Fe3O4 (Alg-Fe3O4), and alginate-magnetic hydroxyapatite (Alg-mHap) using ferric chloride (III) crosslinker to remove cefixime from an aqueous solution. FTIR, SEM, VSM, BET, and XRD ...
Read More
In this study, alginate, magnetite, and hydroxyapatite were used to fabricate alginate-hydroxyapatite (Alg-Hap), alginate-Fe3O4 (Alg-Fe3O4), and alginate-magnetic hydroxyapatite (Alg-mHap) using ferric chloride (III) crosslinker to remove cefixime from an aqueous solution. FTIR, SEM, VSM, BET, and XRD tests were used to determine the functional groups, morphology, magnetization behavior, surface area, and crystallinity of catalysts, respectively. The optimal pH for the Fenton reaction was determined to be 3.3 for Alg-Hap and Alg-Fe3O4 catalysts and 4 for Alg-mHap catalysts. Increases in the concentration of hydrogen peroxide (1 to 3 mM) and the amount of catalyst (50 to 90 gr/L) increased the percentage of degradation to approximately 8% and 6%, respectively. The degradation efficiency of cefixime by using Alg-mHap as the best catalyst in the Fenton process was achieved 91%, at optimum condition (pH of 4, catalyst amount of 90 gr/L, initial cefixime concentration of 5 mg/L, H2O2 concentration of 3 mM within 90 min). Moreover, the second-order kinetic equation fits the experimental data for cefixime degradation for all three catalysts. Furthermore, not only did the catalysts display a negligible iron leaching (0.92 mg/L for Alg-mHap) but also after three consecutive cycles, the catalysts indicated long-term stability. Comparison between synthesized catalysts and other methods proved its effectiveness.
Mahdieh Chegeni; Mozhgan Mehri; Mehdi Hosseini
Abstract
The MoS2/S-doped graphitic carbon nitride (MoS2/S-g-C3N4) was synthesized by a simple method and applied for methylene blue (MB) removal as an organic pollutant. The structure of MoS2/S-doped graphitic carbon nitride was characterized using FTIR, XRD, SEM, TGA and BET techniques. The accomplishment of ...
Read More
The MoS2/S-doped graphitic carbon nitride (MoS2/S-g-C3N4) was synthesized by a simple method and applied for methylene blue (MB) removal as an organic pollutant. The structure of MoS2/S-doped graphitic carbon nitride was characterized using FTIR, XRD, SEM, TGA and BET techniques. The accomplishment of MoS2/S-doped graphitic carbon nitride as an adsorbent was investigated to removal of MB from aqueous solution. The various parameters were studied such as: pH, initial MB concentration, adsorbent dose, temperature and time. The best findings were obtained at pH=8, 8 ppm MB concentration, 0.05 g MoS2/S-g-C3N4, 30 min and 22 ˚C. The Langmuir isotherm model was adopted with the obtained data. The kinetic studies were showed that the adsorption of methylene blue can be well described by the second-order equation. Maximum adsorption was calculated as 166 mg/g. The degradation of MB was studied by MoS2/S-doped graphitic carbon nitride under Light Emmition Diode (LED). Results showed that the MoS2/S-doped graphitic carbon nitride can enhance photocatalytic activity compared to pure g-C3N4 and MoS2/g-C3N4. The findings confirmed that the MoS2/S-doped graphitic carbon nitride can be applied as an efficient, low-cost adsorbent, and photocatalyst to remove of cationic dyes such as methylene blue.
Shahryar Nazarpour Laghani; Azadeh Ebrahimian Pirbazari
Abstract
In this work, multi-walled carbon nanotubes (MWCNTs)/Co-TiO2 nanocomposites were synthesized and investigated for photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) under visible light. Characterization of photocatalysts was done by means of XRD, FT-IR and SEM/EDX techniques. Obtained results ...
Read More
In this work, multi-walled carbon nanotubes (MWCNTs)/Co-TiO2 nanocomposites were synthesized and investigated for photocatalytic degradation of 2,4-dichlorophenol (2,4-DCP) under visible light. Characterization of photocatalysts was done by means of XRD, FT-IR and SEM/EDX techniques. Obtained results showed cobalt doping can inhibit phase transformation from anatase to rutile and eliminate the recombination of electron-hole pairs. The presence of MWCNTs can both increase the photoactivity and change surface properties to achieve sensitivity to visible light. The optimum mass ratio of MWCNTs and cobalt (Co) dopant in TiO2 was the prominent factor to harvest MWCNTs/Co-TiO2 photocatalyst. The sample containing 3.13 wt% cobalt exhibited the highest activity under visible light for 2,4-DCP degradation, which was completed within 180 min using a 0.1 g/L dose of this photocatalyst in a 40 mg/L solution of the 2,4-DCP. The reactions follow the first-order kinetics. The reaction intermediates were identified by GC–MS technique. GC–MS analysis showed the major intermediates of 2,4-DCP degradation are simple acids like oxalic acid, acetic acid, etc. as the final products.
Zahra Sarteep; Azadeh Ebrahimian Pirbazari; Mohammad Ali Aroon
Abstract
Hydrothermally synthesized TiO2 nanoparticles containing different amounts of silver were characterized by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM/EDX) techniques. XRD results showed prepared ...
Read More
Hydrothermally synthesized TiO2 nanoparticles containing different amounts of silver were characterized by X-Ray diffraction (XRD), Fourier transform infrared (FT-IR) and scanning electron microscopy equipped with energy dispersive X-ray microanalysis (SEM/EDX) techniques. XRD results showed prepared samples include 100% anatase phase. The presence of silver in TiO2 nanoparticle network was established by XRD, SEM/EDX and FT-IR techniques. The photocatalytic performance of the prepared catalysts was tested for the degradation of 2,4-dichlorophenol (2,4-DCP) under visible light.. The experiments demonstrated that 2,4-DCP was effectively degraded in the presence of Ag/TiO2 samples. It was confirmed that the presence of Ag on TiO2 catalysts could enhance the photocatalytic degradation of 2,4-DCP in aqueous suspension. It was found that an optimal dosage of 1.68 wt% Ag in TiO2 achieved the fastest 2,4-DCP degradation (95% after 180 min irradiation) under the experimental conditions. On the basis of various characterizations of the photocatalysts, the reactions involved to explain the photocatalytic activity enhancement due to Ag doping include a better separation of photogenerated charge carriers. GC-MS analysis showed the major intermediates of 2,4-DCP degradation are simple acids like oxalic acid, acetic acid, etc. as the final products.