Abstract

With the recent surge in pharmaceutical micro-pollutants found in water bodies, an efficient method to neutralize wastewater is necessary to sustain the ecosystem. This research compares the degradation effectivity of ibuprofen (IBP), a widely consumed NSAID, as a contaminant in the presence of ZnO and without. ZnO is known to be a common catalyst in the degradation of contaminants found in wastewater. The result of photocatalytic degradation of IBP using ZnO is then compared to the results of photodegradation of IBP using no catalyst and only ultraviolet (UV) light.

Introduction

Although the wastewater treatment plant (WWTP) can neutralize up to approximately 95% of these pharmaceutical components, pharmaceutical micro-pollutants still end up in the environment at low concentrations, in which its toxicological effects remain. 

Ibuprofen is the world's third most consumed drug. It is also a dominating pharmaceutical micro-pollutant and highly toxic to the environment.

Experimental Procedure

#1 Making Ibuprofen (IBP) solution and adding ZnO

#2 Magnetic stirring and UV treatment

#3 Sample extraction every 15 minute interval

#4 Centrifuge to separate ZnO

#4 Checking the concentration of the IBP using UV-Vis spectrophotometer

#5 Data analysis

Result

By increasing the irradiation time, more IBP can be degraded at the end. 

Degradation of IBP by UVC showed higher degradation efficiency in the 3rd and 4th intervals when compared with UVC/ZnO, and overall brought higher degradation efficiency rate.

Degradation of IBP by UVC/ZnO showed higher degradation efficiency only in the 1st and 2nd intervals when compared with UVC, but overall brought lower degradation efficiency rate.

The inefficiency of ZnO was most probably caused by the competition for adsorption sides on the surface of the ZnO by the IBP and the byproduct that was formed.

In the degradation of IBP by UVC/ZnO, there is no change in the second peak in the UV-Vis spectrum, indicating that there is a possible complete degradation of the by-product within the first interval.

In the degradation of IBP by UVC, there is an increase in absorbance of the second peak in the first interval, resulting from the formation of by-product from the IBP degradation. After 60 minutes, there is a complete degradation of the by-product.

Conclusion

• The results showed that IBP degradation efficiency is slightly higher without the presence of ZnO at 94.8% when compared to the IBP degradation efficiency in UVC/ZnO at 91.4% after 60 minutes of irradiation time.

• 4-isobutylacetophenone, a by-product of IBP degradation could have been formed during the process as the increase in the second absorbance peak coincides with the degradation of IBP in the first interval (UVC treatment).

• UVC/ZnO shows no increase in the second peak, possibly indicating that the by-product is formed and completely degraded within the first interval.

• This study proves that ZnO increases the degradation efficiency with 82.8% of IBP degradation in the first 30 minutes of the process, in which its catalytic abilities slow down after this time.

• Treatment of IBP without ZnO shows a more consistent degradation process until the end.

• Degradation of clotrimazole using the same setup can reach a maximum degradation efficiency of 95.5% in 60 minutes using the optimum ZnO concentration of 1.0 g/L.

Future Outlook

In future studies, it is important to investigate the effect of catalyst concentration and temperature on IBP degradation efficiency. To broaden the scope of the investigation, degradation efficiency of other dominating pharmaceutical micro-pollutants, such as antibiotics and antivirals, using other catalysts, like TiO2, should also be examined.