Integration of UV light, activated carbon and photocatalytic nanomaterial technologies for point-of-use water treatment in rural areas in Colombia: performance assessment

Colombia is a nation with pronounced socioeconomic differences, where access to potable water remains a challenge without an effective solution, especially in rural areas. This research explores the feasibility of integrating three non-conventional technologies, at the forefront of scientific advanc...

Full description

Autores:: Angel Imitola, Luis Eduardo

Tipo de recurso:: Doctoral thesis

Fecha de publicación:: 2024

Institución:: Universidad de los Andes

Repositorio:: Séneca: repositorio Uniandes

Idioma:: eng

Description
Summary:	Colombia is a nation with pronounced socioeconomic differences, where access to potable water remains a challenge without an effective solution, especially in rural areas. This research explores the feasibility of integrating three non-conventional technologies, at the forefront of scientific advances, for the future design of a sustainable point-of-use water treatment system for rural communities in the country. The first technology employed was activated carbon, used primarily as an adsorbent for organic contaminants present in water. The activated carbon in this research was produced from chontaduro seeds, a locally abundant waste biomass, using a direct physical activation method with steam. A factorial design and multi-objective optimization process that considered key properties from both an operational and sustainability standpoint were used. The resulting activated carbon was thoroughly characterized, demonstrating outstanding properties. The second technology evaluated was irradiation with ultraviolet (UV) light as a disinfectant agent, considering its capacity to damage the genetic material and cell membranes of pathogenic microorganisms and its capacity to break complex organic molecules into simpler compounds. Finally, the third integrated technology was the use of photocatalytic nanoparticles, particularly titanium dioxide (TiO2), capable of generating reactive oxygen species when irradiated with UV light. These species have the ability to mineralize organic contaminants and attack pathogenic microorganisms, offering an additional mechanism for water purification. The study involved the synthesis and characterization of hybrid materials, using activated carbon as a support matrix and coating it with TiO2 nanoparticles by the sol-gel method. Ibuprofen (IBU) was selected as a representative organic pollutant and Escherichia coli as a microbiological indicator to determine the effectiveness of the technologies studied, conducting experiments under controlled conditions. Regarding IBU, the results showed that activated carbon has a remarkable adsorption capacity for IBU, and that this capacity is higher when ions are present in the water at concentrations similar to those of soft surface water. Furthermore, the adsorption capacity is not unique to IBU, but can also be applied to a broad spectrum of organic contaminants. UV radiation at adequate intensities can degrade IBU, although complete mineralization is not achieved, generating by-products during the process. On the other hand, when coating the carbon with TiO2 nanoparticles, a reduction in its IBU adsorption capacity was observed, but when irradiating the material with UV light, the photocatalytic effect of the nanoparticles compensates for this decrease. As for E. coli, UV light proved to be a very effective disinfectant. However, the presence of activated carbon can generate a shadowing effect that prevents the correct irradiation of the microorganisms, reducing the removal efficiency as the amount of carbon increases. However, by coating the activated carbon with TiO2 nanoparticles, the photocatalytic effect can compensate for the shadowing effect, increasing the removal efficiency of E. coli. These results show that the synergistic effects between the technologies improve the treatment efficiency, exceeding the results obtained by each technology independently. The findings of this study suggest that the integration of these technologies is not only viable, but also offers a promising solution to improve water quality in rural areas of Colombia. The system's ability to inactivate microorganisms and remove organic contaminants makes it a sustainable alternative, which can be adapted to the needs of communities without access to centralized treatment systems. In addition, the use of chontaduro seeds as raw material for the production of activated carbon contributes to the sustainable approach of the project, prioritizing the objectives of the circular economy.

Integration of UV light, activated carbon and photocatalytic nanomaterial technologies for point-of-use water treatment in rural areas in Colombia: performance assessment

Publicaciones similares