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Electrochemical Treatment of Sulphidic Spent Caustic Waste Stream Generated from Petroleum Refineries
Journal
Environmental Science and Engineering
ISSN
18635520
Date Issued
2022-01-01
Author(s)
James, Merin Susanna
Garg, Anurag
Abstract
The objective of present study was to assess the performance of electro-Fenton (EF) process for treatment of the simulated sulphidic SCS (sulphide concentration = 10 g/L and pH = 13.7) using iron electrodes. The experimental runs were performed with simulated wastewater at an adjusted pH of ~ 5 with varying H2O2 dosages of 0.31–1.56 M. The current density, electrode spacing and agitation speed were maintained at 1 mA/cm2, 3 cm and 500 rpm, respectively. The treatment process resulted in complete degradation of sulphides, though the chemical oxygen demand (COD) was not fully removed (upto ~91%). It was observed that the addition of super-stoichiometric H2O2 dosage (i.e., 1.56 M) even caused a decrease in the COD removal. Mere adjustment of wastewater pH to 5 resulted in ~ 48% sulphide removal due to H2S stripping which is just almost 50% of the overall sulphide removal during EF process. Hence, EF process can be considered a potential alternative for the removal of sulphides from spent caustic stream.
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