Degradation of Diclofenac in Urine by Electro-Permanganate Process Driven by Microbial Fuel Cells

A novel microbial fuel cell-assisted electro-permanganate process (MFC-PM) was proposed for enhanced diclofenac degradation compared to that of the permanganate oxidation process. By utilizing eco-friendly bio-electricity in situ, the MFC-PM process could activate the simultaneous anodic biological metabolism of urea and the cathodic electro-permanganate process. Density functional analysis and experimental evidence revealed the reactive manganese species (Mn(VII)aq, Mn(VI)aq, Mn(V)aq, and Mn(III)aq), generated via single electron transfer, contributed to diclofenac degradation in the cathodic chamber. The sites of diclofenac with a high Fukui index were preferable to be attacked by reactive manganese species, and diclofenac degradation was mainly accomplished through the ring hydroxylation, ring opening, and decarboxylation processes. Biological detection revealed clostridia were the primary electron donor in the anode chamber in an anaerobic environment. Furthermore, maximum output power density of 1.49 W m−3 and the optimal removal of 94.75% diclofenac were obtained within 20 min under the conditions of pH = 3.0, [DCF]0 = 60 µM, and [PM]0 = 30 µM. Diclofenac removal efficiency increased with external resistance, higher PM dosage, and lower catholyte pH. In addition, the MFC-PM process displayed excellent applicability in urine and other background substances. The MFC-PM process provided an efficient and energy-free bio-electricity catalytic permanganate oxidation technology for enhancing diclofenac degradation.

Monitoring of the main parameters of pond water in order to obtain safe products for joint cultivation of sturgeon and carp fish

The article presents the results of studying the hydrochemical regimes of carp ponds in polyculture and for the introduction of sterlet (Acipenser ruthenus) into polyculture. The highest pH values were in pond 2, and in the second half of June and the first half of July exceeded the upper limit of normal (norm 6.5–8.5) by 0.3 and 0.5, respectively. In July, the upper limit of the norm was exceeded in the water of pond 1, by 0.1 and 0.2, respectively. From August, the pH of water increased in both ponds until October and in pond 2 the active reaction of water was higher, compared to pond 1, 5.08.2020, by 18.3 %, 20.08.2020 by 12.3 %, 5.09.2020, by 3.8 %, 20.09.20 and 5.10.20, respectively by 2.5 and 2.4 %. Higher in pond 2, compared with pond 1, was the permanganate oxidation of water in all studied periods, but the largest difference was 5.07.2020 and amounted to 6.9 mg O/l. In the second half of July, permanganate oxidation of water was the lowest, but was at the upper limit of normal, then in August increased sharply and was highest in October – 26.3 mg O/l in the pond 1 and 26.5 mg O/l in the pond 2. Dichromatic oxidation of water of the studied ponds was during the experiment in pond 2 slightly higher than normal and ranged from 50.5 (5.06.2020) to 57.9 (5.07.2020) mg O/l and only 20.07.2020 it was the lowest and was 34.2 mg O/l. In pond 1, the dichromate oxidation of water at the beginning of the experiment was 52 mg O/l, gradually decreased and 20.06.2020, was 46 mg O/l, in July, the chemical oxygen demand (COD) increased sharply to 63.6 and also decreased sharply up to 40.5 mg O/l. From 05.08.2020, COD rose by 27.8 % above normal, remained at approximately the same level during September and decreased to 62 mg O/l in early October. The content of free ammonia in the water during the whole period of fish farming exceeded the norm from 2.6 to 5 times, and the highest, except for 20.06.2020, it was in pond 2. The highest difference in ammonia content in the water of the studied ponds was 5.07.2020 and 5.10.2020, and was, respectively, 0.1 and 0.08 mg N/l. The content of ammonium nitrogen and mineral phosphorus in the water of the studied ponds exceeded the norm, and the nitrogen content of nitrates and nitrites was within the norm. In pond water, the concentration of Ca2+, Mg2+, Na+, CO32-, HCO3-, SO42-, Cl-did not exceed the norm. was 5.07.2020, and was 1.20 mg/dm³, which is higher than the norm by 20 %. The total hardness and mineralization of water in the studied ponds did not exceed the norm.

Potassium permanganate oxidation as a carboxylation and defibrillation method for extracting cellulose nanofibrils to fabricate films with high transmittance and haze

Cellulose-based films have attracted significant attention in the fields of flexible photoelectric products and energy equipment by virtue of their abundant sources, biodegradability, renewability, sustainability, and optical properties, of which...