The degradation of aqueous solutions containing phenolphthalein was carried out using ozone and electrochemical processes; the two different treatments were performed for 60 min at pH 3, pH 7, and pH 9. The electrochemical oxidation using boron-doped diamond electrodes processes was carried out using three current density values: 3.11 mA·cm−2, 6.22 mA·cm−2, and 9.33 mA·cm−2, whereas the ozone dose was constantly supplied at 5±0.5 mgL−1. An optimal degradation condition for the ozonation treatment is at alkaline pH, while the electrochemical treatment works better at acidic pH. The electrochemical process is twice better compared with ozonation.

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In this work, it has been evaluated how the performance of an electrolyzer, used to treat a clopyralid waste and directly powered without regulation by a battery, is influenced by the electrodes resistance. Electrolyzers were equipped with electrodes consisting of the same boron-doped diamond (BDD) coating deposited on different substrate (Si, Ta and Nb). The results expose great differences despite using the same coating. Faster removal rates were attained with Ta-and Nb-BDD electrodes. The amount of energy required to attain the same removal efficiency showed great differences. Up to 1.95 mg/Wh of pesticide were removed when using Si, compared to 2.14 mg/Wh removed with Ta. Furthermore, the quantity and strength of the generated oxidants were also quite different. 86.78 mmol of oxidants were needed to remove a gram of pesticide with Ta-BDD and 30.57 mmol with Si-BDD. Therefore, the electrode resistance is an important aspect that must be considered in order to get a suitable design of energy storage systems that allow the green photovoltaic powering of electrochemical technologies using conventional batteries as a booster to ensure a continuous operation.