Removal of Diclofenac in Effluent of Sewage Treatment Plant by Photocatalytic Oxidation

Abstract

Diclofenac (DCF) has been widely found in sewage treatment plants and environmental water bodies, and has attracted worldwide attention. In this paper, the photocatalytic degradation of DCF was investigated using a laboratory-scale simulated solar experimental device. This study focused on exploring the effects of the actual secondary effluent from sewage treatment plants (SE-A and SE-B) on the photocatalytic degradation of DCF and the changes of dissolved organic matter (DOM) during the photocatalytic degradation process. The results showed when SE-A and SE-B were used as the background water of the DCF solution, they displayed a significant inhibitory effect on the degradation of DCF, and the values of k were 0.039 and 0.0113 min−1, respectively. Among them, DOM played a major inhibitory role in photocatalytic degradation of DCF in sewage. In the photocatalytic process, the biological toxicity of the DCF solution was the least after 30 min of reaction, and then gradually increased. Furthermore, the organic matters in the sewage were greatly degraded after the photocatalytic reaction, including 254 and 365 nm ultraviolet (UV254, UV365) and chemical oxygen demand (COD). Moreover, titanium dioxide (TiO2) first catalyzed the degradation of macromolecular organic matters, and then degraded the small molecular organic matters.

The progress and prospect for sustainable development of waste wool resources

“…Several methods that have been used for treating sewage are chemical precipitation, membrane filtration, ion exchange, reverse osmosis, solvent extraction, photocatalytic, and adsorption. 24–29 Some of these methods are limited by secondary pollution, high cost, or low treatment efficiency. The absorption method using adsorbents is the most attractive and common one due to having advantages of simple operation and lack of pollution.…”

Degradation of diclofenac under irradiation of UV lamp and solar light using ZnO photo catalyst

“…With increases in catalyst amount up to 0.25 g/L, the catalyst loading DCF degradation was promising, but further increases in loading led to drop in elimination process (Figure 3). It was found that increases in the catalyst loading supported the degradation process, but excessive amounts of catalyst can shield part of the photosensitive surface and consequently hinder or lag in degradation (Ma et al, 2020). This threshold loading depends upon the reactor geometry, operating conditions, and initial substrate concentration.…”

“…Semiconductor photocatalysis based on TiO2 and ZnO induced by UV/solar irradiation have been extensively studied for pharmaceutical pollutants treatment (Petru et al, 2020& Rehman et al, 2021& Ma et al, 2020. In photo catalytic degradation of pollutants the processes utilizes the UV spectrum to photo excite the catalyst resulting in generation of hydroxyl radicals in the presence of oxygen.…”

Removal of Diclofenac Sodium from Wastewater in Microbial Fuel Cell by Anode Modified with MnCo2O4

“…Approximately 940 tons of DCF are consumed worldwide every year [9,10]. DCF has the highest acute toxicity among non-steroidal drugs and is one of the pharmaceuticals which, due to its high consumption and resistance to biodegradation, is mostly detected in water sources; it can be detected in the inlet and outlet of water and wastewater treatment plants, with high concentrations of up to a gram per liter [2,10]. DCF is dangerous for human and animal health.…”

“…Even at the lowest concentration, it has led to cytological changes in the liver and kidneys [9]. In 2019, the French Agency for Food, Environmental and Occupational Health & Safety (ANSES) published a notice on the possible health consequences of the DCF presence in surface water and reported the permissible amount of DCF at 0.4 µg/L [3,9,10]. Lethal concentration of DCF is 480 ± 50 µg/L (LC50/96 h) and the effect concentration is 90 ± 20 µg/L (EC50/96 h).…”