Removal of dinitrotoluene from petrochemical wastewater by Fenton oxidation, kinetics and the optimum experiment conditions

Abstract

The performance of Fenton oxidation processes with simultaneous application of two oxidants including (H 2 O 2 ) and sodium persulfate (Na 2 S 2 O 8 ), in the presence of iron (Fe 2+ ) as a catalyst to oxide dinitrotoluene (DNT) was investigated. For optimization of processes, the effect of operational parameters such as solution pH, oxidant dosages, reaction time and initial DNT concentrations on their performance was evaluated. All experiments were conducted at room temperature (25 ± 2 °C). For all studied processes, the efficiency of pollutant removal was enhanced by increasing the oxidant dosages, while it witnessed a reduction with increasing the initial DNT concentration. The results showed that Fe 2+ /H 2 O 2 / Na 2 S 2 O 8 system was more efficient in alkaline conditions and the oxidizing of DNT followed pseudo-first-order kinetics. At optimum conditions, the mineralization degree was higher than 86%. Moreover, high potential of DNT removal in a petrochemical effluent sample was observed. Fenton process in the presence of simultaneous application of Na 2 S 2 O 8 and H 2 O 2 can be used as an effective and promising method for petrochemical wastewaters treatment, due to high efficiency in contaminants removal and also high potential of mineralization.

Petrochemical wastewater and produced water: Treatment technology and resource recovery

“…Several research efforts were made in the Fenton oxidation processes. To remove dinitrotoluene (DNT) from petrochemical wastewater, the Fenton oxidation process was tested with both hydrogen peroxide and sodium persulfate with ferrous iron as a catalyst (Takdastan, Ravanbakhsh, Hazrati, & Safapour, 2019). The system was less efficient in acidic conditions, and the DNT mineralization rate was more than 86%.…”

Kinetics of Nitric Oxide Absorption from Flue Gas Using an Advanced Oxidation Process with Sodium Persulfate Solution

“…28−30 It was found that Na 2 S 2 O 8 can react with OH • and enhance the oxidation of the solution in a weakly basic solution. 31 For ships, seawater with a pH of 7.6−8.4 32 could be considered as a natural alkaline solvent. However, it is not clear if seawater is suitable for the Na 2 S 2 O 8 system to oxidize and remove NO.…”

“…Among these oxidants, Na 2 S 2 O 8 has been widely used in the removal of organic toxic gases, treatment of organic contaminants in groundwater, and remediation of diesel-contaminated soil − for its high stability, low cost, environmental friendliness, and good oxidation properties. In recent years, Na 2 S 2 O 8 has gradually entered the field of wet denitrification to oxidize NO. , Many improved methods on additives or complex solutions for Na 2 S 2 O 8 solutions have been reported, which were mainly explored to improve the effect on the removal of NO x . − It was found that Na 2 S 2 O 8 can react with OH · and enhance the oxidation of the solution in a weakly basic solution . For ships, seawater with a pH of 7.6–8.4 could be considered as a natural alkaline solvent.…”