Degradation of Odontologic X-Ray Film Developing Wastewaters by Photo-Fenton Process

Author(s):  
Luciana Igarashi-Mafra ◽  
Edmilson César Bortoletto ◽  
Maria Angelica Simões Dornella Barros ◽  
Amanda Cristina Alfredo Contrucci Sorbo ◽  
Naiara Aguiar Galliani ◽  
...  

Effluents from radiographic X-ray film developing processes feature a high contaminant load (COD about 70000 mg/L and total phenols concentration about 16956 mg/L). Photo-Fenton's are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence of light to generate hydroxyl radicals (·OH). The photo-Fenton process was explored as a photochemical treatment to degrade wastewater from radiographic X-ray film developing processes coming from odontologic clinics. A response surface methodology was applied to optimize the photo-Fenton oxidation process conditions using total phenol removal as the target parameter to be optimized, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and time and pH as the control factors to be optimized. The best results in terms of maximal total phenol removal and economic process were achieved when wastewater samples were treated at pH 5 in the presence of hydrogen peroxide and iron in the ratios [total phenols]:[H2O2] 1:3 w/w and [Fe2+]:[H2O2] 1:18 w/w and time 1 h.

Author(s):  
Siqi Bao ◽  
Yuqi Shi ◽  
Youshan Zhang ◽  
Longjie He ◽  
Wangyang Yu ◽  
...  

Abstract As organic dyes are the main pollutants in water pollution, seeking effective removal solutions is urgent for humans and the environment. A novel environmentally friendly three-dimensional CoFe-LDHs (3D CoFe-LDHs) catalyst was synthesized by one-step hydrothermal method. Scanning electron microscopy, energy dispersive spectroscopy, Fourier transform infrared spectra, X-ray diffraction, X-ray photoelectron spectroscopy, Brunauer-Emmett-Teller technique as well as UV-Vis diffuse reflectance spectra were used to characterize the prepared samples. The experimental results revealed that 3D CoFe-LDHs exhibited a rapid decolorization of methyl orange and Rhodamine B by heterogeneous photo-Fenton process after reaching the adsorption equilibrium, and the final decolorization efficiency reached 91.18% and 93.56%, respectively. On the contrary, the decolorizing effect of 3D CoFe-LDHs on neutral blue was relatively weak. The initial concentrations of azo dyes, pH and H2O2 concentration affected the decolorization of dyes and the catalyst maintained excellent reusability and stability after reuse over five cycles. The quenching experiments found that •OH, •O2− and h+ were the main active substances and reaction mechanisms were further proposed. The study suggests that the synergistic effect of photocatalysis and Fenton oxidation process significantly improved the removal of azo dyes and the synthesized catalyst had potentially promising applications for difficult-to-biodegrade organic pollutants in wastewater.


2010 ◽  
Vol 9 (3) ◽  
pp. 351-360 ◽  
Author(s):  
Abdelnaser Omran ◽  
Hamidi Abdul Aziz ◽  
Marniyanti Mamat Noor

Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.


1989 ◽  
Vol 54 (12) ◽  
pp. 3253-3259
Author(s):  
Jaroslav Podlaha ◽  
Miloš Buděšínský ◽  
Jana Podlahová ◽  
Jindřich Hašek

The unusual product of the reaction of 2-chloroacrylonitrile with ethane thiol and following hydrogen peroxide oxidation was found to be (E)-1,2-bis(ethylsulphonyl)cyclobutane-1,2-dicarbonitrile by means of X-ray crystallography. 1H and 13C NMR study of this compound has proven the same conformation of the molecule in solution.


Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1349
Author(s):  
Ahlam Khalofah ◽  
Mona Kilany ◽  
Hussein Migdadi

Heavy metals are primarily generated and deposited in the environment, causing phytotoxicity. This work evaluated fenugreek plants’ morpho-physiological and biochemical responses under mercury stress conditions toward Ag nanoparticles and Sphingobacterium ginsenosidiumtans applications. The fabrication of Ag nanoparticles by Thymus vulgaris was monitored and described by UV/Vis analysis, FTIR, and SEM. The effect of mercury on vegetative growth was determined by measuring the root and shoots length, the number and area of leaves, the relative water content, and the weight of the green and dried plants; appraisal of photosynthetic pigments, proline, hydrogen peroxide, and total phenols content were also performed. In addition, the manipulation of Ag nanoparticles, S. ginsenosidiumtans, and their combination were tested for mercury stress. Here, Ag nanoparticles were formed at 420 nm with a uniform cuboid form and size of 85 nm. Interestingly, the gradual suppression of vegetal growth and photosynthetic pigments by mercury, Ag nanoparticles, and S. ginsenosidiumtans were detected; however, carotenoids and anthocyanins were significantly increased. In addition, proline, hydrogen peroxide, and total phenols content were significantly increased because mercury and S. ginsenosidiumtans enhance this increase. Ag nanoparticles achieve higher levels by the combination. Thus, S. ginsenosidiumtans and Ag nanoparticles could have the plausible ability to relieve and combat mercury’s dangerous effects in fenugreek.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3209
Author(s):  
Aphiwe Siyasanga Gugushe ◽  
Anele Mpupa ◽  
Tshimangadzo Saddam Munonde ◽  
Luthando Nyaba ◽  
Philiswa Nosizo Nomngongo

In this study, Fe3O4-ZrO2 functionalized with 3-aminopropyltriethoxysilane (Fe3O4-ZrO2@APS) nanocomposite was investigated as a nanoadsorbent for the removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions from aqueous solution and real samples in batch mode systems. The prepared magnetic nanomaterials were characterized using X-ray powder diffraction (XRD), scanning electron microscopy/energy dispersion x-ray (SEM/EDX) Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). Factors (such as adsorbent dose and sample pH) affecting the adsorption behavior of the removal process were studied using the response surface methodology. Under optimized condition, equilibrium data obtained were fitted into the Langmuir and Freundlich isotherms and the data fitted well with Langmuir isotherms. Langmuir adsorption capacities (mg/g) were found to be 113, 111, 128, and 123 mg/g for Cd, Cu, Ni and Mn, respectively. In addition, the adsorption kinetics was analyzed using five kinetic models, pseudo-first order, pseudo-second order, intraparticle diffusion and Boyd models. The adsorbent was successfully applied for removal of Cd(II), Cu(II), Mn (II) and Ni(II) ions in wastewater samples.


2014 ◽  
Vol 1049-1050 ◽  
pp. 39-43 ◽  
Author(s):  
Qin Hong Ji ◽  
Salma Tabassum ◽  
Chun Feng Chu ◽  
Chun Jie Li ◽  
Zhen Jia Zhang

Coal gasification wastewater, as a typical industrial wastewater has poor biodegradability and high toxicity. In this paper, simple anaerobic shaker test was conducted to investigate the degradation of hydroquinone in coal gasification wastewater. Anaerobic sludge shaker test were run for 27, 50 and 73 days, the phenol concentration were adjusted to 300 mg/L and 500 mg/L with pH 7.5, respectively. The experimental results also showed that this system could effectively deal with COD and phenol removal and remain in a stable level when the operational parameters altered while the hydrolysis acidification at 45h is appropriate. Organics degradation and transformation of anaerobic coal gasification wastewater samples at 12h, 24h, 36h, 48h, and 60h were analyzed by GC/MS and it was found that hydrolysis acidification played an important role in degradation of methyl phenol, hydroquinone and refractory compounds. Therefore, the results illustrated that the simple anaerobic shaker process is an easy way for pollutant degradation and treat coal gasification wastewater effectively.


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