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Advanced oxidation technology based on PeroxyMonoSulfate (PMS) has become a research hotspot in the field of water treatment. To improve the activation efficiency of PMS, electrochemically assisted spinel type catalyst CoFe2O4 was used to activate PMS and achieve effective degradation of acetaminophen. The influence of single factor on degradation was explored to determine the best degradation process parameters of E/CoFe2O4/PMS system. Results show that under the optimum reaction conditions (DC voltage is 6V, the initial mass concentration of acetaminophen is 10mgL−1, the dosage of CoFe2O4 is 0.3gL−1, and the mass concentration of PMS is 1.5gL−1), the degradation rate of acetaminophen reaches up to 95% within 20min. CoFe2O4 catalyst showed a good stability, with only a 12% decrease in acetaminophen degradation after three cycles. Radical quenching tests show that ⋅OH and SO4−⋅ played predominant roles in the advanced oxidation process. This work provides a new strategy for more efficiency in PMS activation. [ABSTRACT FROM AUTHOR]

In this work, to improve the performance of peroxodisulphate-advanced oxidation, an electrochemical oxidation-assisted UV light-activated peroxodisulphate system (E/UV/PDS) was used to degrade carbamazepine. The degradation of carbamazepine by PDS, E/PDS, UV/PDS and E/UV/PDS systems was compared, and their synergistic effects were analysed. The influence of single factors, such as PDS addition, initial pH, DS voltage, target initial concentration, etc., on the degradation of the E/UV/PDS system was discussed, and the optimal degradation process parameters were given. The active substances were determined by free radical inhibition experiments, such as 1O2, ${\rm SO}_4^- \cdot$ SO 4 − ⋅ and $\cdot {\rm OH}$ ⋅ OH . It was proved that 1O2 contributes much more to the degradation of carbamazepine than ${\rm SO}_4^- \cdot$ SO 4 − ⋅ and $\cdot {\rm OH}$ ⋅ OH . The degradation pathway of carbamazepine was proposed. Finally, the degradation mechanism of carbamazepine in the E/UV/PDS system was speculated. The results indicate that the electrochemical combined with the E/UV/PDS system is of great potential application value in the removal of antibiotic drug pollution and environmental purification. [ABSTRACT FROM AUTHOR]

In response to the issues of poor water flooding efficiency, low oil production rates, and low recovery rates during the high-water-cut period in the low-permeability reservoirs of the Mutou Oilfield, the non-steady-state (NSS) CO2 huff-n-puff oil recovery technology was explored. The NSS CO2 huff-n-puff can improve the development effect of low-permeability reservoirs by replenishing the reservoir energy and significantly increasing the crude oil mobility. Experimental investigations were carried out, including a crude oil and CO2–crude oil swelling experiment, minimum miscibility pressure testing experiment, high-temperature and high-pressure microfluidic experiment, and NSS CO2 huff-n-puff oil recovery on-site pilot test. The experimental results showed that the main mechanisms of NSS CO2 huff-n-puff include dissolution, expansion, viscosity reduction, and swept volume enlargement, which can effectively mobilize the remaining oil from the various pore throats within the reservoir. The high-temperature and high-pressure microfluidic experiment achieved an ultimate recovery rate of 83.1% for NSS CO2 huff-n-puff, which was 7.9% higher than the rate of 75.2% obtained for steady injection. This method can effectively utilize the remaining oil in the corners and edges, enlarge the swept volume, and increase the recovery rate. Field trials of NSS CO2 huff-n-puff in a low-permeability reservoir in the Mutou Oilfield indicated that it cumulatively increased the oil production by 1134.5 tons. The achieved results and insights were systematically analyzed and could provide key technical support for the application of NSS CO2 huff-n-puff technology in low-permeability reservoirs, promoting the innovative development of this technology. [ABSTRACT FROM AUTHOR]

To enhance the catalytic activity of CuFe2O4 on PS, a nanoscale oxygen-vacancy CuFe2O4 was prepared by hydrogenation reduction technique to construct an advanced oxidation system of electrochemical-enhanced nanoscale oxygen-vacancy CuFe2O4-activated persulfate. Using Ebselen (EBS) as a model pollutant, the degradation efficiency, activation mechanism and degradation pathway were studied. The oxygen-vacancy CuFe2O4 was characterized and analysed by FESEM, EDS and XPS. The results show that under the optimal reaction conditions (PS = 0.8 g/L, oxygen-vacancy CuFe2O4 = 0.3 g/L, initial pH = 6.5), the removal rate of 20 mg/L EBS can reach 92% after reaction for 60 min, which proves that the formation of oxygen-vacancy changed the catalytic inertness of CuFe2O4 on PS. It is speculated that in the E/oxygen-vacancy CuFe2O4/PS system, the existence of oxygen holes enhances the electron transfer ability and reducibility of the catalyst, so the oxygen-vacancy CuFe2O4 can efficiently activate PS to degrade EBS. The quenching experiments show that both ${\rm SO}_4^{\cdot -}$ SO 4 ⋅ − and $\cdot {\rm OH}$ ⋅ OH are involved in the oxidation reaction as reactive radicals in the system, with ${\rm SO}_4^{\cdot -}$ SO 4 ⋅ − being the main reactive radical. In addition, both dissolved oxygen (DO) and anions in the solution inhibit the oxidative degradation of EBS by oxygen-vacancy CuFe2O4/PS system. Through GC-MS detection, a possible degradation pathway is proposed. [ABSTRACT FROM AUTHOR]

Carbamazepine (CBZ) is a common antiepileptic drug. CBZ enters the environment through unreasonable and standardized ways such as human and animal metabolites, discarded drugs, and more than half of its metabolites are released into the environment. Since CBZ is not easy to be degraded, continuous input of CBZ into the water environment will cause long-term impact on the water ecological environment and seriously endanger human health. Aiming at how to degrade wastewater containing carbamazepine, studies were conducted on the degradation of carbamazepine by ultrasound/zero-valent iron/persulfate system (US/ ${\rm F}{\rm e}^0$ F e 0 /PS). Firstly, the removal effects of carbamazepine by different systems, such as ultrasound/sodium persulfate (US/PS), zero-valent iron/persulfate system (${\rm F}{\rm e}^0$ F e 0 /PS) and US/ ${\rm F}{\rm e}^0$ F e 0 /PS, were compared; Secondly, the influence of factors, such as ultrasonic power, sodium persulfate dosage, zero-valent iron dosage, reaction temperature, pH, etc., on the reaction was investigated by the control variables method. Results show that ultrasound power, PS concentration, pH and temperature have a great influence on the removal of carbamazepine in US/Fe0/PS reaction system. Besides, the optimum parameters for degradation of carbamazepine with US/ ${\rm F}{\rm e}^0$ F e 0 /PS reaction system were determined ([CBZ]0 = 0.025 mM; [PS]0 = 0.4 mM; Fe0 = 4.0 mg/L; ultrasonic power = 40 W; T = 30 ℃; initial pH = 5.0). Finally, the intermediates and degradation pathways of carbamazepine by US/ ${\rm F}{\rm e}^0$ F e 0 /PS system were analyzed and speculated. It was inferred that two intermediates were generated during the degradation of carbamazepine, mainly through the ring opening and decyclization of piperazine rings. It was proved that process US/ ${\rm F}{\rm e}^0$ F e 0 /PS has a very important application value in the degradation of antibiotic-containing wastewater. [ABSTRACT FROM AUTHOR]