Microbial fuel cells are a promising technology for future wastewater treatment, as it allows cle... more Microbial fuel cells are a promising technology for future wastewater treatment, as it allows cleaning and power generation simultaneously. The bottleneck of microbial fuel cells is often its cathodes because they determine the power output. Gas diffusion electrodes might overcome this bottleneck due to their low production costs and high oxygen reduction rates. However, biofilm formation on the gas diffusion electrodes reduces their performance over time. In this work, a new reactor design of the microbial fuel cell using rotating gas diffusion electrodes is presented. The biofilm growth on the electrode during operation was observed and its effect on the performance of the microbial fuel cell was examined. In addition, different antifouling strategies were investigated over a period of 80 days. It was found that already after 7 days of operation a complete biofilm had grown on an untreated gas diffusion electrode. However, this does not seem to affect the performance of the cells ...
A system of boron-doped diamond (BDD) anode combined with a gas diffusion electrode (GDE) as a ca... more A system of boron-doped diamond (BDD) anode combined with a gas diffusion electrode (GDE) as a cathode is an attractive kind of electrolysis system to treat wastewater to remove organic pollutants. Depending on the operating parameters and water matrix, the kinetics of the electrochemical reaction must be defined to calculate the reaction rate constant, which enables designing the treatment reactor in a continuous process. In this work, synthetic wastewater simulating the vacuum toilet sewage on trains was treated via a BDD-GDE reactor, where the kinetics was presented as the abatement of chemical oxygen demand (COD) over time. By investigating three different initial COD concentrations (C0,1 ≈ 2 × C0,2 ≈ 4 × C0,3), the kinetics was presented and the observed reaction rate constant kobs. was derived at different current densities (20, 50, 100 mA/cm2). Accordingly, a mathematical model has derived kobs. as a function of the cell potential Ecell. Ranging from 1 × 10−5 to 7.4 × 10−5 s−...
Electrochemical advanced oxidation processes (EAOP®) are promising technologies for the decentral... more Electrochemical advanced oxidation processes (EAOP®) are promising technologies for the decentralized treatment of water and will be important elements in achieving a circular economy. To overcome the drawback of the high operational expenses of EAOP® systems, two novel reactors based on a next-generation boron-doped diamond (BDD) anode and a stainless steel cathode or a hydrogen-peroxide-generating gas diffusion electrode (GDE) are presented. This reactor design ensures the long-term stability of BDD anodes. The application potential of the novel reactors is evaluated with artificial wastewater containing phenol (COD of 2000 mg L−1); the reactors are compared to each other and to ozone and peroxone systems. The investigations show that the BDD anode can be optimized for a service life of up to 18 years, reducing the costs for EAOP® significantly. The process comparison shows a degradation efficiency for the BDD–GDE system of up to 135% in comparison to the BDD–stainless steel elect...
To enable the evaluation of water treatment efficiency of electrochemical advanced oxidation proc... more To enable the evaluation of water treatment efficiency of electrochemical advanced oxidation processes (EAOPs), an approach to remove H 2 O 2 as a catalytic pretreatment was investigated to avoid interference in chemical oxygen demand (COD) measurements. Four wastewater types with COD and H 2 O 2 concentrations up to 1,300 mg=L and 90 mmol=L, respectively, were investigated with a novel method. The method requires the addition of sodium bicarbonate (NaHCO 3), which decomposes H 2 O 2 at ambient temperature within 24 h without changing COD. For synthetic wastewater (SWW), this time is reduced to 1 h by heating at 70°C. A side-by-side comparison of NaHCO 3 and Na 2 CO 3 experiments confirmed H 2 O 2 removal without changes in COD via NaHCO 3 , whereas a ∼20% decrease in original COD was observed using Na 2 CO 3. The change in COD during catalytical H 2 O 2 decomposition in Na 2 CO 3 solution was highly correlated with the high pH value.
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Papers by Mohammad Issa