Asst. Prof. Dr . Aula M. Al Hindawi
Hiba Ali Hamzah
Department of chemistry, College of Education for Pure Sciences, University of Karbala, Iraq.
It is any physical or chemical change that has a negative effect on living organisms and water quality, as it becomes harmful when used [1].
Defined according to the World Health Organization: as any change that occurs to the elements included in its composition, directly or indirectly, due to human activity, which makes this water less suitable for natural uses. Physical pollution is the result of material factors such as radiation, heat, etc., which are due to the presence of microorganisms such as germs present in the water and are highly dangerous to live in, especially those that cause diseases. As for chemical pollutants, they are either dissolved or suspended in water [2]. The existence of organic molecules like alkaloids, acids, and other substances is what causes chemical pollutants to exist in the aquatic environment.
Many pharmaceutical preparations have been found in surface water, wastewater, and groundwater, as well as in drinking water in the range from monograms to micrograms due to their low biodegradability and high hydrophobicity. Residues from pharmaceutical preparations are also a major problem affecting the environment and living organisms, especially, antibiotics and steroids, which cause resistance in normal bacteria [3].
Methods of treating polluted water:
There are many technologies that have been developed to decontaminate liquid wastes laden with various chemicals, and these technologies such as activated sludge, ion exchange, membrane bioreactor system, filtration, and adsorption on different surfaces. Recently, research has also shown that adsorption is the most effective method for treating pollution of water. Physiochemical techniques such as adsorption showed high efficiency in removing pharmaceutical compounds from wastewater. Adsorption was used in the treatment of industrial water pollutants, especially inorganic compounds and toxic compounds present in water systems that contain lead, medicines, and other chemicals that are harmful to human health. Additionally, there are some that cannot be separated using filters, such as sterilization or filtration [4].
The ability of solid or liquid objects to draw gas molecules or aqueous solutions to their surface and come into touch with them directly is known as adsorption. The reason for the occurrence of the phenomenon of adsorption is due to the existence of remnants of unsaturated fields of forces with electrons due to the incomplete consistency or contact of a sufficient number of particles with the surface particles, and this is what is represented in the solid or liquid phase, where adsorption leads to saturation of the fields of these forces on the surface and thus It will causing the free energy to drop off the surface, that is, the adsorption process will be automatic, with a decrease in the degrees of freedom of the adsorbent, which is expressed thermodynamically by a decrease in entropy [5]. Many factors affect the adsorption process, including the adsorbent surface’s nature and the nature of the adsorb material. The effect of ionic strength, the effect of pH, particle size, and temperature.
There are many ways to get rid of drug contaminants, including:
1- By zonation, photolysis, and adsorption, activated carbon was used as an adsorbent surface to remove the drug (Mefenamic Acid )from wastewater, as this technique showed a maximum removal efficiency of (60%) after (120) minutes when combined with ultraviolet radiation [6].
2- Activated carbon and red clay were used as adsorbents to remove MFA, which gave removal efficiencies of (100%) and (96%), respectively, before oxidation with chlorine [7].
3-Using TiO2 particles as an adsorbent surface for the adsorption of Mefenamic Acid in wastewater, where the removal efficiency was (97.5%) within 90 min [8].
4- The different advanced oxidation method was used to remove the Mefenamic Acid, where impacts of pH and the concentration of the oxidizer and catalyst on the degradation of the MFA was looked into. The removal efficiency was further improved by using ultraviolet light with hydrogen peroxide to 98% in 20 minutes in the acidic pH range [9].
This work focused mainly on the preparation of SnO2 Nanocrystals using the chemical precipitation method. Where tin oxide nanoparticles with a semi-spherical shape were prepared by controlling the concentration of raw materials, the pH of the solution, and the reaction time. By using several techniques, the formation of SnO2 Nanocrystals was confirmed (TEM, FE-SEM, XRD, DRS, EDS).
The band gap energy of the ultraviolet-visible spectrum was also measured and found to be (3.7ev). The observation of the redshift is attributed to the quantum confinement effect. Tin oxide nanoparticles were used as an adsorbent surface for the adsorption of Mefenamic Acid, which is one of the pharmaceutical pollutants of the water.
Reference:
1. Chowdhary, P., et al., Role of industries in water scarcity and its adverse effects on environment and human health. Environmental Concerns and Sustainable Development: Volume 1: Air, Water and Energy Resources, 2020: p. 235-256.
2. Goel, P., Water pollution: causes, effects and control. 2006: New age international.
3. Mansouri, F., et al., Removal of Pharmaceuticals from water by adsorption and advanced oxidation processes: State of the art and trends. Applied Sciences, 2021. 11(14): p. 6659.
4. Milačić, R., Species in the environment, food, medicine and occupational health. 2005, John Wiley and Sons: New York, NY, USA.
5. Shaw, D.J., Introduction to colloid and surface chemistry. 1980: Butterworths.
6. Gimeno, O., et al., Application of advanced oxidation processes to Mefenamic acid elimination. International Journal of Nuclear and Quantum Engineering, 2010. 4(6): p. 399-401.
7. Moruzzi, R.B., et al., Mefenamic acid removal in water using activated carbon powder, red mud and oxidation with chlorine. Química Nova, 2014. 37: p. 1594-1599.
8. Shanian, Z.Y., M.F. Abid, and K. Sukkar, Photodegradation of mefenamic acid from wastewater in a continuous flow solar falling film reactor. Desalin. Water Treat, 2021. 210: p. 22-30.
9. Deepa, R., G. Madhu, and R.M. Thomas, A comparative study on the removal of an emerging contaminant mefenamic acid from aqueous media by various advanced oxidation methods. Materials Today: Proceedings, 2021. 47: p. 1416-1422.
