Diploma Thesis Defense by Mrs. Anthi Stefanarou
Thesis Title: «THE INTERACTION OF TITANIUM DIOXIDE (TiO2) IN FORMALDEHYDE (FA) IN THE PRESENCE OF SAND IN STATIC AND DYNAMIC CONDITIONS» »
Friday 5 June 2020, at: 13:00
Examination Committee
- Professor Constantinos Chrysikopoulos (advisor)
- Professor Ioannis Tsanis
- Professor George Karatzas
Abstract
One of today’s major problems is the pollution of marine and natural resources. The demand for clean, potable water is becoming greater due to the dramatic increase in the earth’s population. Clean water reserves are decreasing and for this reason new technology is constantly being developed for its purification. Titanium dioxide nanoparticles are a promising manmade nanomaterial with applications in technology, energy storage, pharmacology and electrocatalysm. Titanium is found in carbon, ashes, plants and even the human body. Formaldehyde is an extremely active compound used extensively on a daily basis, hence, the probability of its release into the environment and resulting polluting of the surface and underground water is of great importance. Since both materials are released into the environment it is worthwhile to study the interaction between the two substances. The use of titanium dioxide nanoparticles as an absorbent could be a good solution for the restoration of the environment.
In order to evaluate the first stage of interaction of the titanium dioxide nanoparticles with the formaldehyde static and dynamic batch experiments were carried out in which the absorption of formaldehyde in titanium dioxide was studied. In the second stage the interaction of formaldehyde with mixtures of quartz sand and titanium dioxide were studied so that
The second stage studied the interaction of formaldehyde with mixtures of quartz sand and titanium dioxide was studied so as to evaluate the removal capability of the specific organic compounds from water solutions present in both absorbents. Quartz sand was chosen to simulate the soil as it is the most common mineral on the face of the earth. Both sets of experiments were carried out in vials at a room temperature of 25°C with three different concentrations of formaldehyde 3mg/L, 5mg/L, 8mg/L at three different pH levels 4, 7.5, 10 and add three different ionic concentrations 1mM, 50mM, 100mM. Finally flow experiments were performed in a bent tube filled with quartz sand and saturated with water so as to define the movement characteristics of the titanium dioxide nanoparticles alone but also with the addition of a solution of formaldehyde.
For the analysis of the results, a modeling of the experimental data was executed using the ColloidFit software program. Based on the results it was observed that the maximum removal of formaldehyde occurs with the combination of titanium dioxide and quartz sand. It can remove up to 99 percent of the particular compound from water samples. Additionally, it came about that the experimental data is described better by the pseudo-second order model indicating that the main absorption mechanism is likely chemical absorption.
