Effect of thermal and mechano-chemical activation on the photocatalytic efficiency of ZnO for drugs degradation

Abstract

Over the past few years, pharmaceutical drugs have been considered as emerging pollutants due to their continuous input and persistence in the aquatic ecosystem even at low concentrations. They have been detected worldwide in environmental matrices, indicating their ineffective removal from water and wastewaters using conventional methods. In this study we present photocatalytic purification of water from Acetaminophen and Chloramphenicol by ZnO upon UV-light illumination. Commercial ZnO powders are activated thermally (annealed at different temperatures-100, 200, 300, 400 and 500 °C for 1 h) and mechanically (treated for 5, 15, 20, 30, 40 and 60 min). The mechonoactivation is performed varying the atmosphere in air, or in suspension of ethanol and methanol. The changes in the studied material (phase composition, structure and particle size of the samples) and morphology have been investigated by means of X-ray diffraction and Scanning electron microscopy. The ZnO powders annealed at 100 °C show highest photocatalytic efficiency and rate constant of dye degradation, which is due to the smaller size of nanocrystallites and their better developed surface. The degradation rate of Acetaminophen and Chloramphenicol increases with time of mechanical activation up to 30 min and then decreases. The optimal temperature and time of mechanoactivation are experimentally established.

Recent advances in removal of pharmaceutical pollutants in wastewater using metal oxides and carbonaceous materials as photocatalysts: a review

“…The photodegradation of paracetamol (20 mg L −1 ) has been investigated in the presence of nanostructured TiO 2 catalysts with a nanotubetype morphology using ultraviolet radiation (λ: 254 nm) and the removal efficiency was found to be 99% after 100 min. 83 The photocatalytic degradation of acetaminophen in water has also been reported using ZnO, 84 faceted-TiO 2 85 and molecularly imprinted ZnO nanonuts. 86 3.1.2 Metal-incorporated metal oxides.…”

“…Therefore, attention has focused on its removal from aqueous media following a photocatalysis approach, as described below. 79–147…”

“…ZnO powders (Fluka)84 Commercial (thermally calcined at 100 °C)50 mg L −1 0.25 g (0.25 L) -UV-lamp (315-400 nm), P.D: 0.66 mW cm −AuCl 6 , stirring and irradiating with 450 W ACE lamp for 1 h 20 mg L −1 0.4 g L −1 6.3 Simulated solar light xenon lamp (1000 W), 50.0 mW cm −…”

Emerging Pollutants – Part II: Treatment

“…For the purpose of obtaining photocatalyst, Kaneva et al (2016) MIT, respectively), COB showed higher photocatalytic activity than MIT. The results showed that the diclofenac photodegradation by COB/H2O2/simulated sunlight system followed pseudo-first-order kinetics (kapp= 0.046 min -1 ).…”

Highly efficient and Reusable ZnO microflower photocatalyst on stainless steel mesh under UV–Vis and natural sunlight

“…There is contradictory views on effect of film thickness for photocatalytic activity. Some report suggest that increase of film thickness improves the photocatalytic activity whereas some researcher showed that film thickness has no effect on photocatalytic activity [33][34][35].P. Jongnavakit et al have used sol gel derived ZnO thin film on glass substrate for degradation of Methylene Blue (MB) [36].…”