Essay Sample on Nano Plastics: Charge Distribution, Zeta Potential, and Gut Fluids

Introduction

The Nano plastics particles react at different PH levels because the aqueous solution influenced the charge distribution on the surface affecting the zeta potentials as well as the hydrodynamic microsphere when complex chemical compounds found in the gut fluid such as Mg+, Na+, and K+ are present (Liu et al., 2017). The zeta potential decreases with increasing PH and increases in the presence of other chemicals such as Mg+, Na+, and K+ because of the electrostatic repulsion of interparticle. When a negative group is present on the surface of a polystyrene microsphere in the process of polymerization, it can lead to negative zeta potential in a big range of PH. In the initial stages of the polymerization reaction, the decomposition of potassium persulfate generates free radicals of SO4-. This radical therefore attaches itself on the surface of the ultimate polystyrene microsphere to form a negatively charged surface. High zeta potentials are found in Na+ and K+ as compared to Mg+ as a result of steric repulsions. The hydrodynamic diameter is also affected by the presence of Mg+, Na+, and K+ which neutralizes charges resulting in agglomeration of polystyrene microsphere (Songhua et al., 2018). At low PH, the repulsive electrostatic forces are weak which leads to substantial big thicknesses of the polystyrene microsphere.

Is your time best spent reading someone else’s essay? Get a 100% original essay FROM A CERTIFIED WRITER!

Save 25%

The morphological characterization of the particles also affects the absorption rate with absorption peaks being as a result of a stretched C=C aromatic ring, double bonded Hydrogen and Hydroxyl vibration of the water molecules and aliphatic deformation C-N (Jin et al., 2015). The peak absorption points at different diameters can also be linked to the presence of benzene ring, C-H deformation. Cation and anion concentration also matters. The zeta potential decreases with increasing concentration of Na+ and K+ while Mg+ causes a slight increase (the increase can be as a result of reduced surface negative charge). This effect can be attributed to good compression of an electrostatic bilayer of double bonded ions as compared to single bonded ions (Hou et al, 2017). The addition of SO42- increases zeta potential because the electrostatic dual layer is compressed at increased concentrations. At low concentrations of Chlorine ions (Cl-), Hydrogen Carbonate ions (HCO3-) and SO42- the polystyrene microsphere form rough surfaces and smooth surfaces on higher concentrations because of the shielding effect formed by counter ions (Mukherjee & Weaver, 2010).

Increasing the concentration of Mg+ results in bigger polystyrene microsphere than Na+ and K+ because the former is better antagonistic in altering the double layered electrical thickness (Shih et al., 2012). It also neutralizes the surface negative charges decreasing electrostatic repulsion hence aggregation of polystyrene size. The anions and cations also affect the hydrodynamic diameter of the polystyrene microsphere. SO42- causes a higher diameter which can be attributed to increased compression on the electrical bi-layer by opposite action of Na+. Therefore at high concentrations, there is a high aggregation of the polystyrene microsphere as a result of weakened electrostatic repulsive forces. Consequently, with decreased surface charge, and increased concentration of the cations and anions causes destabilization.

During the retention time in the stomach where the PH is around 2, the nanoparticles may be changed or aggregated. Induration of 3 hours, the particles would not change very much, it would aggregate but not significantly bigger, but after it enters the intestine cecum and colon, during the residual time in the human body, it could aggregate to a bigger size of particles. This is because, as it progresses down the digestive tract, more compounds are added onto it which may contain more Cl-, HCO3-, SO42 Mg+, Na+ and K+ which accelerate the increase in the size of the particles. The PH also decreases at various levels which further accelerates the process. Therefore in particles where the zeta potential is dependent on PH, can lead to alteration of surface chemistry of the particles (Loretz et al., 2007)

References

Hou, J., Zhou, Y., Wang, C., Li, S. and Wang, X., 2017. Toxic effects and molecular mechanism of different types of silver nanoparticles to the aquatic crustacean Daphnia Magna. Environmental science & technology, 51(21), pp.12868-12878.

Liu, H., Li, M., Chen, T., Chen, C., Alharbi, N.S., Hayat, T., Chen, D., Zhang, Q. and Sun, Y., 2017. A new synthesis of nZVI/C composites as an efficient adsorbent for the uptake of U (VI) from aqueous solutions. Environmental science & technology, 51(16), pp.9227-9234.

Loretz, B. and Bernkop-Schnurch, A., 2007. In vitro cytotoxicity testing of non-thiolated and thiolated chitosan nanoparticles for oral gene delivery. Nanotoxicology, 1(2), pp.139-148.

Lu, S., Zhu, K., Song, W., Song, G., Chen, D., Hayat, T., Alharbi, N.S., Chen, C. and Sun, Y., 2018. Impact of water chemistry on surface charge and aggregation of polystyrene microspheres suspensions. Science of the total environment, 630, pp.951-959.

Mukherjee, B. and Weaver, J.W., 2010. Aggregation and charge behavior of metallic and nonmetallic nanoparticles in the presence of competing for similarly-charged inorganic ions. Environmental science & technology, 44(9), pp.3332-3338.

Shih, Y.H., Zhuang, C.M., Peng, Y.H., Lin, C.H. and Tseng, Y.M., 2012. The effect of inorganic ions on the aggregation kinetics of lab-made TiO2 nanoparticles in water. Science of the total environment, 435, pp.446-452.