Optimised photocatalytic degradation of a mixture of azo dyes using a TiO2/H2O2/UV process

2012 ◽  
Vol 65 (8) ◽  
pp. 1392-1398 ◽  
Author(s):  
Soraya Moreno Palácio ◽  
Fernando Rodolfo Espinoza-Quiñones ◽  
Aparecido Nivaldo Módenes ◽  
Diego Ricieri Manenti ◽  
Cláudio Celestino Oliveira ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Azo Dyes ◽  
Irradiation Time ◽  
Optimum Conditions ◽  
Order Model ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
Full Factorial Experimental Design ◽  
Two Parameters ◽  
Full Factorial

The aim of the present study was to optimise the photocatalytic degradation of a mixture of six commercial azo dyes, by exposure to UV radiation in an aqueous solution containing TiO2-P25. Response surface methodology, based on a 32 full factorial experimental design with three replicates was employed for process optimisation with respect to two parameters: TiO2 (0.1–0.9 g/L) and H2O2 (1–100 mmol/L). The optimum conditions for photocatalytic degradation were achieved at concentrations of 0.5 g TiO2/L and 50 mmol H2O2/L, respectively. Dye mineralisation was confirmed by monitoring TOC, conductivity, sulfate and nitrate ions, with a sulfate ion yield of 96% under optimal reactor conditions. Complete decolorisation was attained after 240 min irradiation time for all tested azo-dyes, in a process which followed a pseudo-first kinetic order model, with a kinetic rate constant of approximately 0.018 min−1. Based on these results, this photocatalytic process has promise as an alternative for the treatment of textile effluents.

scholarly journals Factorial experimental design for the removal of disperse dyes using hydroxyapatite prepared from Moroccan phosphogypsum

2019 ◽  
Vol 8 (1) ◽  
pp. 1-9
Author(s):  
Meryeme Joudi ◽  
Jihan Mouldar ◽  
Houyem Hafdi ◽  
Hamid Nasrellah ◽  
Badreddine Hatimi ◽  
...  
Keyword(s):  
Experimental Design ◽  
Azo Dyes ◽  
Textile Industry ◽  
Contact Time ◽  
Disperse Dyes ◽  
Synthetic Dyes ◽  
Optimal Conditions ◽  
Factorial Experimental Design ◽  
Full Factorial Experimental Design ◽  
Full Factorial

Azo dyes are the major group of synthetic dyes known and have given rise to many water and soil environmental problems, the most of this azo dyes were used in textile industry. The aim of this study is the removal of Disperse Blue 79 (DB 79) and Disperse Blue 165 (DB 165) as azo dyes by Hydroxyapatite (HAP). The adsorption experiments were carried out to investigate the factors that influence the dyes uptake by hydroxyapatite, such as the contact time under agitation, adsorbent dosage, initial dye concentration and size of HAP. To reduce the number of experiments, full factorial experimental design at two levels (24) was used to achieve optimal conditions for the removal of DB 79 and DB 165 from aqueous solutions.

scholarly journals Optimum conditions for the synthesis of high solubility carboxymethyl chitosan

2014 ◽  
Vol 10 (4) ◽  
Author(s):  
Mardiyah Kurniasih ◽  
Purwati Purwati ◽  
Dadan Hermawan ◽  
Muhamad Zaki
Keyword(s):  
Reaction Time ◽  
Carboxymethyl Chitosan ◽  
Monochloroacetic Acid ◽  
Optimum Conditions ◽  
High Solubility ◽  
Synthesis Conditions ◽  
Acid Ratio ◽  
Full Factorial Experimental Design ◽  
Full Factorial

A research on optimizing the synthesis conditions to obtain carboxymethyl chitosan with the highest solubility in 1%(v/v) acetic acid solvent have been performed. Optimization was performed by varying: the concentration of NaOH during alkalizing the chitosan, chitosan: monochloroacetic acid ratio, temperature and reaction time. This study uses a full factorial experimental design. The results showed that the highest solubility was found in 40% (w/v) NaOH concentration, chitosan to monochloroacetic acid ratio of 1:7, reaction temperature of 80°C and reaction time at 4 hours with the solubility up to 63.78 mg /mL. IR and 1H-NMR spectra showed that the synthesis gave result to carboxymethyl chitosan. Results of physical characterization of carboxymethyl chitosan at the highest solubility showed the value of water content, ash content, molecular weight, and swelling effects up to 14.27%, 8.48%, 2,86978 x 105 g/mol; and 884.19%, respectively.

scholarly journals Efficient removal of 2-chlorophenol from aqueous solution using TiO2 thin films/alumina disc as photocatalyst by pulsed laser deposition

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
S. Ismat Shah ◽  
Sawsan A. Mahmoud ◽  
Samar H. Bendary ◽  
Ahmed K. Aboulgheit ◽  
A. A. Salem ◽  
...  
Keyword(s):  
Thin Films ◽  
Photocatalytic Degradation ◽  
Pulsed Laser Deposition ◽  
Catalyst Surface ◽  
Irradiation Time ◽  
Pulsed Laser ◽  
Textural Properties ◽  
Laser Deposition ◽  
Hydroxyl Groups ◽  
Tio2 Thin Films

AbstractPulsed laser deposition facilitates the epitaxial deposition and growth of TiO2 at low temperature on hot substrate. In this study, nanosized nitrogen-doped TiO2 thin films were deposited on fabricated alumina disc-shaped and glass substrates. Textural properties of the fabricated disc and alumina disc-supported TiO2 were investigated using N2 adsorption–desorption isotherms, field emission scanning electron microscopy (FESEM), X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. FESEM showed the presence of single crystals of TiO2 on the alumina disc. FTIR showed the presence of octahedral TiO2 and different hydroxyl groups on the surface which is responsible for the photoactivity and also showed the functional groups adsorbed on the catalyst surface after the photocatalytic degradation. The concentration of 2-chlorophenol and the photo-redox intermediate products as a function of irradiation time was determined. The concentration of the produced chloride ion during the photocatalytic degradation was determined by an ion chromatography. The results showed that the photocatalytic activity of the catalyst decreased upon cycling. The obtained results were compared with nanostructured TiO2 supported on glass substrate. Higher efficiency of 100% degradation was achieved for TiO2/Al2O3 catalyst, whereas about 70% degradation of 2-CP was achieved using TiO2/glass. Different photointermediates of 2-CP degradation have been identified for each cycle. The difference of intermediates is supported by the adsorbed fragments on the catalyst surface.

Immobilization of Nano-TiO2 on Expanded Perlite for Photocatalytic Degradation of Rhodamine B

2011 ◽  
Vol 110-116 ◽  
pp. 3795-3800 ◽  
Author(s):  
Xiao Zhi Wang ◽  
Wei Wei Yong ◽  
Wei Qin Yin ◽  
Ke Feng ◽  
Rong Guo
Keyword(s):  
Catalytic Activity ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Degradation Kinetics ◽  
Irradiation Time ◽  
Sol Gel ◽  
Polluted Water ◽  
Order Kinetic ◽  
Expanded Perlite ◽  
Initial Concentration

Expanded perlite (EP) modified titanium dioxide (TiO2) with different loading times were prepared by Sol-Gel method. Photocatalytic degradation kinetics of Rhodamine B (RhB) in polluted water by the materials (EP-nanoTiO2), as well as the effects of different loading times and the initial concentration of RhB on photocatalysis rate were examined. The catalytic activity of the regenerated photocatalyst was also tested. The results showed that photocatalyst modified three times with TiO2had the highest catalytic activity. Degradation ratio of RhB by EP-nanoTiO2(modified three times) under irradiation for 6 h were 98.0%, 75.6% and 63.2% for 10 mg/L, 20 mg/L and 30 mg/L, respectively.The photocatalyst activity has little change after the five times recycling, and the degradation rate of RhB decreased less than 8%. The reaction of photocatalysis for RhB with irradiation time can be expressed as first-order kinetic mode within the initial concentration range of RhB between 10mg/L and 30 mg/L. EP-nanoTiO2photocatalyst has a higher activity and stability to degrade RhB in aqueous solution.

Sign in / Sign up

Export Citation Format

Share Document