In situ photodecyanation of steel industry wastewater in a pilot scale

Biswas, Pinakpani; Bhunia, Prasenjit; Saha, Priyanka; Sarkar, Supriya; Chandel, Harsh; De, Sirshendu

doi:10.1007/s11356-020-09632-0

Cited by 12 publications

(8 citation statements)

References 16 publications

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“…The calculated apparent rate constants (k app ) were calculated to be 0.016, 0.030, 0.018, and 0.017 min −1 for TO, La/TO, Ce/TO, and Eu/TO nanoparticles, respectively. These results are in agreement with those reported by other authors [ 48 , 73 ]. The results obtained in the photocatalytic degradation test are shown in Figure 11 .…”

Section: Resultssupporting

confidence: 94%

“…Due to this transfer, radical superoxide anions ( • O 2 − ) and hydroxyl radicals ( • OH) are generated through a series of sequential reactions (Equations (26)–(29)). The following reactions suggest the likely pathway for ROS photogeneration on the surface of Ln (n+) /TiO 2 (Ln (n+) = La (3+) , Ce (3+/4+) , or Eu (3+) ) [ 73 , 89 ]:

…”

Section: Discussionmentioning

confidence: 99%

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Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

Jaramillo-Fierro

León

2023

Nanomaterials

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Free cyanide is a highly dangerous compound for health and the environment, so treatment of cyanide-contaminated water is extremely important. In the present study, TiO2, La/TiO2, Ce/TiO2, and Eu/TiO2 nanoparticles were synthesized to assess their ability to remove free cyanide from aqueous solutions. Nanoparticles synthesized through the sol–gel method were characterized by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transformed infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), and specific surface area (SSA). Langmuir and Freundlich isotherm models were utilized to fit the adsorption equilibrium experimental data, and pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to fit the adsorption kinetics experimental data. Cyanide photodegradation and the effect of reactive oxygen species (ROS) on the photocatalytic process were investigated under simulated solar light. Finally, reuse of the nanoparticles in five consecutive treatment cycles was determined. The results showed that La/TiO2 has the highest percentage of cyanide removal (98%), followed by Ce/TiO2 (92%), Eu/TiO2 (90%), and TiO2 (88%). From these results, it is suggested that La, Ce, and Eu dopants can improve the properties of TiO2 as well as its ability to remove cyanide species from aqueous solutions.

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Section: Resultssupporting

confidence: 94%

…”

Section: Discussionmentioning

confidence: 99%

Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

Jaramillo-Fierro

León

2023

Nanomaterials

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“…The apparent rate constants (k app ) were determined to be 0.003, and 0.018 min −1 for GP and GTA, respectively. These results are in agreement with those reported by other authors [ 51 , 55 ]. Figure 10 depicts that both samples achieved the maximum percentage of MB degradation within approximately the initial 90 min, after which the photodegradation appeared to plateau.…”

Section: Resultssupporting

confidence: 94%

Porous Geopolymer/ZnTiO3/TiO2 Composite for Adsorption and Photocatalytic Degradation of Methylene Blue Dye

et al. 2023

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In this study, GP (geopolymer) and GTA (geopolymer/ZnTiO3/TiO2) geopolymeric materials were prepared from metakaolin (MK) and characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), scanning electron microscopy (SEM), energy dispersive X-rays (EDX), specific surface area (SSA), and point of zero charge (PZC). The adsorption capacity and photocatalytic activity of the compounds prepared in the form of pellets was determined by degradation of the methylene blue (MB) dye in batch reactors, at pH = 7.0 ± 0.2 and room temperature (20 °C). The results indicate that both compounds are highly efficient at adsorbing MB, with an average efficiency value of 98.5%. The Langmuir isotherm model and the pseudo second order kinetic model provided the best fits to the experimental data for both compounds. In the MB photodegradation experiments under UVB irradiation, GTA reached an efficiency of 93%, being higher than that achieved by GP (4%). Therefore, the incorporation of ZnTiO3/TiO2 in the geopolymeric matrix allowed GTA to achieve higher overall efficiency, by combining adsorption and photocatalysis, compared to the GP compound. The results indicate that the synthesized compounds could be used for up to five consecutive cycles for the removal of MB from wastewater through adsorption and/or photocatalysis processes.

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“…Cyanide (CN) and cyanide compounds, such as HCN, KCN, and NaCN, are a subject of major concern in the iron and steel industry due to their toxicity [1][2][3]. Cyanide forms in flames and high-temperature environments via several possible reaction routes involving e.g.…”

Section: Introductionmentioning

confidence: 99%

“…C 2 , N 2 , C, and CH [4]. The cyanides are typically located in the effluents [2,3,5,6] and leachates [7] in industrial processes. The sources of carbon and nitrogen in these reactions can be the atmosphere inside the furnace, charge material, additive materials, and gas or coke injections.…”

Section: Introductionmentioning

confidence: 99%

Cyanide recombination in electric arc furnace plasma

Pauna

Willms

Aula

et al. 2021

Plasma Res. Express

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Cyanide, among with NO x , CO 2 , and CO, is one of the adverse compounds that form in the ironmaking and steelmaking industry. High-temperature processes are suitable environments for cyanide formation, and cyanide can form as a result of recombination in electric arc plasma. Even though the cyanides might not survive e.g. the post-combustion process, understanding the formation mechanisms of hazardous materials in the steelmaking industry is important. In this work, the recombination of cyanide in a pilot-scale AC electric arc furnace is studied with optical emissions from the CN molecule. The results show how the optical emissions from the cyanide change in different process steps. Electric input, plasma temperature, and interaction of the arc with solid charge material were observed to have an impact on the CN signal. Additionally, equilibrium composition computation highlights how different sources of carbon change the recombination rate and that the highest recombination occurs at 6821 K.

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In situ photodecyanation of steel industry wastewater in a pilot scale

Cited by 12 publications

References 16 publications

Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

Porous Geopolymer/ZnTiO3/TiO2 Composite for Adsorption and Photocatalytic Degradation of Methylene Blue Dye

Cyanide recombination in electric arc furnace plasma

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