The College of Engineering at the University of Baghdad witnessed the public defense of the master’s thesis by Huda Neama Jaber in the Department of Chemical Engineering. His thesis, titled “Elimination of Multi Dyes from Simulated Wastewater by Two and Three-Dimensional Electro-Fenton processes Assisted with Alum Sludge and Iron Filings” was presented on Thursday, 3 September 2026, in Professor Mahmoud Omar Hall within the Department of Chemical Engineering, under the supervision of Prof. Dr. Rasha Habeeb Salman.
This study investigates the electrochemical advanced oxidation processes (EAOPs) for treatment simulated wastewater consisting of 75 mg/L of three dyes (Eosin Y, methylene Blue, and Methylene Violet), utilizing the electro-Fenton (EF) processes.
Three electrochemical system sets were employed with 30 minutes operation time, pH at 3, mixing speed of 300 rpm, and air flowrate of 20 L/hr, in the first set nickel foam (NiF) was used as cathode due to its porous structure and high electrical conductivity, which contributes to improving the efficiency of electrical hydrogen peroxide (H2O2) generation while graphite (G) utilized as anode in two-dimensional EF (2DEF) system. Key operational parameters including current density (CD) (1.4 – 4.2 mA/cm2), FeSO4.7H2O concentration (0.1 – 0.5 mM), and Na2SO4 concentration (0.01 – 0.05 M) were optimized using Box-Behnken Design (BBD). The optimal removal efficiency (Re%) conditions were CD = 4.2 mA/cm2, [FeSO4.7H2O] = 0.2 mM, and [Na2SO4] = 0.05 M, where the Re% and chemical oxygen demand (COD) removal was 95.76 and 100%, respectively with specific energy consumption (SEC) of 5.43 kWh/kg dye. Additionally, the EF system assisted with 20 g/L of alum sludge as third particle in three-dimensional EF (3DEF) system which improved the removal efficiency and decreased the degradation time to 10 minutes, and it was a good alternative source of iron ions in EF system.
In the second set, the carbon fiber felt (CFF) was utilized as cathode, and porous graphite (PG) as anode. The studied operational factors (CD (1.38 – 12.5 mA/cm2), [FeSO4.7H2O] (0.25 – 0.5 mM), and [Na2SO4] (0.015 – 0.05 M)) were optimized using BBD. The highest removal efficiency, 98.59% was achieved at a CD of 12.5 ma/cm2, [Na2SO4] of 0.0325 M, and [FeSO2.7H2O] of 0.5 mM with a consumed energy of 163.77 kWh/kg dye. The addition of 5 g/L alum sludge as a third electrode in a 3DEF system improved the treatment process, provided a good source of catalyst, a cheap and environmentally friendly alternative to costly iron salts in this process, and decrease the treatment time to 15 minutes instead of 30 minutes. Additionally, the reuse of alum sludge has been tested in three cycles and has proven effective in improving Re% and its reusability.
In third set, the NiF was utilized as cathode, CFF as anode, and iron filings (IF) as a heterogeneous source of iron ions in 3DEF system. The BBD was used to optimizing the operational parameters (CD (0.69 – 2.08 mA/cm2), IF (0.25 – 1.5 g/L), and [Na2SO4] (0.01 – 0.02 M)). The highest Re% 96.45 which attained after accomplishing the experiments based on Response Surface Methodology (RSM) was recorded at 2.08 mA/cm2 of CD, 0.25 g/L of IF, and 0.015 M of electrolyte concentration. The highest SEC for this process was 6.89 kWh/kg dye. In addition to the process’s energy efficiency, using iron scrap as a cheap alternative to expensive iron salts is a cost-effective and environmentally friendly approach.
Finally, the reuse of iron filings has been tested in three cycles and has proven effective in maintaining removal efficiency with a slight decrease of no more than one percent. This makes it an environmentally friendly and economical choice in the electro-Fenton process for treating contaminated water.
