Optimizing TOC and COD removal for the biodiesel wastewater by electrocoagulation

Abstract In this study, the chemical oxygen demand (COD) and the total organic carbon content (TOC) in biodiesel wastewater iron and aluminum electrodes arranged in a bipolar position. In the EC of the biodiesel wastewater, the effects of the supporting electrolyte, initial pH, electrolysis time and current density were examined. The results showed that the majority of the pollutants in the biodiesel wastewater were effectively removed when the iron or aluminum electrodes were used as a sacrificial anode. The highest COD and TOC removal efficiencies were successfully obtained with the iron electrode. COD removal efficiencies are 91.74 and 90.94% for iron and aluminum electrode, respectively. In the same way, TOC removal efficiencies were obtained as 91.79 and 91.98% for the iron and aluminum electrodes, respectively, at initial pH of 6, the current density of 0.3226 mA/cm2, NaCl concentration 1 g/L and 1 min of operating time

Valorization of Paper Mill Sludge as Adsorbent in Adsorption Process of Copper (II) Ion from Synthetic Solution: Kinetic, Isotherm and Thermodynamic Studies

This study investigates the process conditions of the adsorption of copper (II) ion onto paper mill sludge (PMS) in a batch process. These conditions are: concentration of initial solution, contact time, temperature and quantity of the adsorbent. Characteristic properties of PMS employed as an adsorbent in the experiments were defined using Fourier transform infrared spectroscopy (FT-IR) scanning electron microscopy (SEM) and elemental analyses. According to the obtained results, while the amount of removed copper (II) ion increased with an increase in the rate of the adsorbent and contact time, it decreased as a result of an increase in the temperature and initial solution concentration. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were implemented for the determination of the most appropriate isotherm model for the experimental data, and it was found that the process is in concordance with Langmuir equation. The maximum adsorption capacity of PMS was calculated as 114.42 mg g. In kinetic studies, the adsorption process of copper (II) ion onto PMS was controlled by the pseudo-second-order kinetic model. The calculated activation value ( was 38.61 kJ mol and demonstrates that the process occurred by physical adsorption mechanism. The values of the thermodynamic parameters such as enthalpy (, free energy () (-8.883 kJ mol) and entropy ( (0.101 kJ mol K) changes were determined to estimate the nature of the process. The results clearly showed that the process was of exothermic and spontaneous nature and that PMS could be utilized as an adsorbent for the removal of copper (II) ion from wastewater

Organic and Carbon Gels Derived from Biosourced Polyphenols

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