Effect of preozonation and prechlorination on total organic carbon removal in surface water treatment in Iran

AbstractIn the present work, the photocatalytic degradation and mineralization of 4-tert-butylphenol in water was studied using Fe-doped TiO2 nanoparticles under UV light irradiation. Fe-doped TiO2 catalysts (0.5, 1, 2 and 4 wt.%) were prepared using wet impregnation and characterized via SEM/EDS, XRD, XRF and TEM, while their photocatalytic activity and stability was attended via total organic carbon, 4-tert-butyl phenol, acetic acid, formic acid and leached iron concentrations measurements. The effect of H2O2 addition was also examined. The 4% Fe/TiO2 demonstrated the highest photocatalytic efficiency in terms of total organic carbon removal (86%). The application of UV/H2O2 resulted in 31% total organic carbon removal and 100% 4-t-butylphenol conversion, however combining Fe/TiO2 catalysts with H2O2 under UV irradiation did not improve the photocatalytic performance. Increasing the content of iron on the catalyst from 0.5 to 4% considerably decreased the intermediates formed and increased the production of carbon dioxide. The photocatalytic degradation of 4-tert-butylphenol followed pseudo-second order kinetics. Leaching of iron was observed mainly in the case of 4% Fe/TiO2, but it was considered negligible taking into account the iron load on catalysts. The electric energy per order was found in the range of 28–147 kWh/m3/order and increased with increasing the iron content of the catalyst.

Download Full-text

Tubular nanofiltration of highly concentrated C.I. Acid Black 210 dye

Water Science & Technology ◽

10.2166/wst.2012.638 ◽

2013 ◽

Vol 67 (4) ◽

pp. 901-906 ◽

Cited By ~ 3

Author(s):

A. Y. Zahrim ◽

N. Hilal ◽

C. Tizaoui

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Dye Removal ◽

Nanofiltration Membrane ◽

Solution Ph ◽

Carbon Removal ◽

Initial Concentration ◽

Membrane Performance ◽

Total Organic Carbon Removal ◽

Fouling Factor

Tubular nanofiltration membrane performance to treat water for reuse was carried out by choosing C.I. Acid Black 210 dye as a model dye. It has been shown that increasing pH causes reduction in irreversible fouling factor (IFF) and the dye removal is also affected by solution pH. The total organic carbon removal for pH 4, pH 7, pH 8 and pH 10 is 97.9, 92.3, 94.5 and 94.6%, respectively. The conductivity removal for pH 4, pH 7, pH 8 and pH 10 is 85.1, 88.3, 87.8 and 90.7% respectively. The increase in the initial dye concentration causes rapid increase in fouling until 100 mg/l. Then the fouling increases gradually as it reaches a maximum IFF around 13%. This study also shows that the colour of permeate changes from colourless to light greenish/yellowish (initial concentration of 2,000 and 4,000 mg/l) as the initial dye concentration increases. The conductivity removal was also reduced as the initial dye concentration increased due to screening of the Donnan effect with the presence of salt.

Download Full-text

Comparative study on electrochemical 4-chlorophenol degradation in different diaphragm systems with combined reduction and oxidation properties

Water Science & Technology ◽

10.2166/wst.2014.473 ◽

2014 ◽

Vol 71 (1) ◽

pp. 126-130 ◽

Cited By ~ 3

Author(s):

S. L. Liu ◽

H. Wang ◽

Z. Y. Bian

Keyword(s):

Organic Carbon ◽

Total Organic Carbon ◽

Electrode System ◽

Hydrogen Gas ◽

Combined Processes ◽

Carbon Removal ◽

Total Organic Carbon Removal ◽

Oxidation Properties ◽

Reduction And Oxidation ◽

The Difference

Two diaphragm electrolysis systems, two-electrode (anode–cathode) and three-electrode (cathode–anode–cathode), were compared for the electrochemical degradation of 4-chlorophenol. The performance of these systems was improved by feeding with hydrogen gas and then with air, in aid of the combined processes of reduction and oxidation. The 4-chlorophenol degradation, dechlorination, and total organic carbon removal were monitored to characterize the difference between the two systems. The results indicated that the three-electrode system exhibited higher degradation percentages for 4-chlorophenol compared with that of the two-electrode system. The dechlorination property of the three-electrode system was stronger than that of the two-electrode system. In addition, the total organic carbon removal percentage of the anodic compartment in the three-electrode system was higher than that of the two-electrode system. The three-electrode system showed excellent treatment properties for 4-chlorophenol.

Download Full-text