Every summer, my family and I travel across the world, 3,000 miles away to the culturally diverse country of India. Now, India is a country infamous for its scorching heat and humidity. For me, the only relief from this heat is to drink plenty of water. Now, while in India, my parents always remind me to only drink boiled or bottled water, because unlike here in America, where I can just turn on a tap and easily get clean, potable water, in India, the water is often contaminated. So my parents have to make sure that the water we drink is safe.
Todos os veráns viaxo 5000 km coa miña familia para ir á India, un país de gran diversidade cultural. Tamén é ben coñecida a súa abafante calor húmida. Eu só consigo aliviala bebendo auga a esgalla. Cando imos alí, os meus pais lémbranme sempre que só beba auga fervida ou embotellada. Mentres que nos EUA non temos máis que abrir a billa para ter auga potable, na India a auga está a miúdo contaminada, de aí que os meus pais teñan que mirar pola auga que bebemos.
However, I soon realized that not everyone is fortunate enough to enjoy the clean water we did. Outside my grandparents' house in the busy streets of India, I saw people standing in long lines under the hot sun filling buckets with water from a tap. I even saw children, who looked the same age as me, filling up these clear plastic bottles with dirty water from streams on the roadside. Watching these kids forced to drink water that I felt was too dirty to touch changed my perspective on the world. This unacceptable social injustice compelled me to want to find a solution to our world's clean water problem. I wanted to know why these kids lacked water, a substance that is essential for life. And I learned that we are facing a global water crisis.
Pero eu decateime dende ben pequena de que non todos tiñan a nosa sorte. Nas rúas da India, onda os meus avós, teño visto xente facendo cola ao sol para encher baldes de auga nunha billa. Mesmo vin nenos da miña idade enchendo as típicas botellas de auga nos regos sucios das cunetas. Ver eses cativos obrigados a beber unha auga que eu nin tocaría cambiou a miña visión do mundo. Esta inaceptable inxustiza social motivoume a buscar unha solución á escaseza de auga potable no mundo. Quería saber por que eses cativos carecían de algo tan esencial para a vida. E descubrín que nos enfrontamos a unha crise global da auga.
Now, this may seem surprising, as 75 percent of our planet is covered in water, but only 2.5 percent of that is freshwater, and less than one percent of Earth's freshwater supply is available for human consumption. With rising populations, industrial development and economic growth, our demand for clean water is increasing, yet our freshwater resources are rapidly depleting. According to the World Health Organization, 660 million people in our world lack access to a clean water source. Lack of access to clean water is a leading cause of death in children under the age of five in developing countries, and UNICEF estimates that 3,000 children die every day from a water-related disease.
Isto pode sorprendernos, xa que 3/4 partes da Terra están cubertas de auga, pero só o 2,5 % dela é auga doce e menos do 1 % desa auga doce está accesible. Co aumento da poboación mundial, o desenvolvemento industrial e o crecemento económico, a nosa demanda de auga potable é cada vez maior, ao tempo que os recursos de auga doce se esgotan con rapidez. Segundo a OMS, 660 millóns de persoas non teñen acceso a auga potable. Nos países en vías de desenvolvemento, esta carencia é unha das principais causas de mortalidade na nenez. UNICEF calcula que 3000 nenos morren cada día polo consumo de auga contaminada.
So after returning home one summer in eighth grade, I decided that I wanted to combine my passion for solving the global water crisis with my interest in science. So I decided that the best thing to do would be to convert my garage into a laboratory.
Así que un día á volta das vacacións de verán, con 14 anos, resolvín combinar dous dos meus intereses, a crise mundial da auga e a ciencia, e decidín que o mellor que podía facer era converter o noso garaxe nun laboratorio.
(Laughter)
(Risos)
Actually, at first I converted my kitchen into a laboratory, but my parents didn't really approve and kicked me out.
En realidade, tenteino primeiro na cociña, pero meus pais non estaban de acordo e chimpáronme de alí.
(Risos)
I also read a lot of journal papers on water-related research, and I learned that currently in developing countries, something called solar disinfection, or SODIS, is used to purify water. In SODIS, clear plastic bottles are filled with contaminated water and then exposed to sunlight for six to eight hours. The UV radiation from the sun destroys the DNA of these harmful pathogens and decontaminates the water. Now, while SODIS is really easy to use and energy-efficient, as it only uses solar energy, it's really slow, as it can take up to two days when it's cloudy. So in order to make the SODIS process faster, this new method called photocatalysis has recently been used.
Tamén lin moitos artigos científicos sobre a auga. E así souben dun método de depuración chamado desinfección solar ou SODIS, o seu acrónimo inglés, que se usa nos países en desenvolvemento. A SODIS consiste en encher de auga botellas de plástico transparente e deixalas entre seis e oito horas ao sol. A radiación UV do sol destrúe o ADN dos xermes patóxenos e desinfecta a auga. A técnica é ben sinxela e non ten gasto enerxético, pero tamén é lenta. Pode alongarse até dous días cando está nubrado. Unha proposta recente para acurtala bota man da fotocatálise.
So what exactly is this photocatalysis? Let's break it down: "photo" means from the sun, and a catalyst is something that speeds up a reaction. So what photocatalysis is doing is it's just speeding up this solar disinfection process. When sunlight comes in and strikes a photocatalyst, like TiO2, or titanium dioxide, it creates these really reactive oxygen species, like superoxides, hydrogen peroxide and hydroxyl radicals. These reactive oxygen species are able to remove bacteria and organics and a whole lot of contaminants from drinking water.
E que é a fotocatálise? Un catalizador é algo que acelera unha reacción, mentres que “foto” fai referencia á luz. Entón o que fai a fotocatálise é acelerar o proceso de desinfección solar. Cando a luz do sol incide sobre un fotocatalizador, como pode ser o TiO₂, ou dióxido de titanio, crea especies reactivas do osíxeno, como superóxidos, auga osixenada e radicais hidroxilos. Estes compostos tan reactivos eliminan moitos contaminantes da auga, incluíndo bacterias e residuos orgánicos.
But unfortunately, there are several disadvantages to the way photocatalytic SODIS is currently deployed. See, what they do is they take the clear plastic bottles and they coat the inside with this photocatalytic coating. But photocatalysts like titanium dioxide are actually commonly used in sunscreens to block UV radiation. So when they're coated on the inside of these bottles, they're actually blocking some of the UV radiation and diminishing the efficiency of the process. Also, these photocatalytic coatings are not tightly bound to the plastic bottle, which means they wash off, and people end up drinking the catalyst. While TiO2 is safe and inert, it's really inefficient if you keep drinking the catalyst, because then you have to continue to replenish it, even after a few uses.
Pero a SODIS fotocatalítica é aínda unha técnica pouco madura. O usual é recubrir o interior das botellas cunha capa de dióxido de titanio, que xusto adoita ser un ingrediente dos protectores solares. Velaquí entón o primeiro problema: ese revestimento interior bloquea parte da radiación UV e diminúe así a eficacia da SODIS. Por outra banda, esa capa non queda ben adherida ao plástico. O catalizador vaise desprendendo co tempo e a xente acaba bebéndoo. Aínda que o TiO₂ é inocuo e inerte, resulta custoso e pouco práctico bebelo, porque isto obriga a repoñelo con frecuencia.
So my goal was to overcome the disadvantages of these current treatment methods and create a safe, sustainable, cost-effective and eco-friendly method of purifying water. What started off as an eighth grade science fair project is now my photocatalytic composite for water purification. The composite combines titanium dioxide with cement. The cement-like composite can be formed into several different shapes, which results in an extremely versatile range of deployment methods. For example, you could create a rod that can easily be placed inside water bottles for individual use or you could create a porous filter that can filter water for families. You can even coat the inside of an existing water tank to purify larger amounts of water for communities over a longer period of time.
Así que o meu obxectivo era perfeccionar a SODIS fotocatalítica para facela segura, sostible, económica e ecolóxica. E o que comezou como un traballo escolar de ciencias deveu no meu composto fotocatalítico para a depuración de auga. O composto combina dióxido de titanio con cemento. A súa textura de cemento permítelle adoptar diversas formas, o que dá lugar a unha gama moi versátil de métodos de aplicación. Por exemplo, pode modelarse unha barra para meter en botellas de uso individual ou un filtro poroso para uso familiar. Mesmo se pode revestir co composto o interior dun depósito comunitario, para que actúe durante máis tempo sobre volumes de auga tamén maiores.
Now, over the course of this, my journey hasn't really been easy. You know, I didn't have access to a sophisticated laboratory. I was 14 years old when I started, but I didn't let my age deter me in my interest in pursuing scientific research and wanting to solve the global water crisis.
O proceso para chegar aquí non foi un camiño doado. Eu non dispoñía dun sofisticado laboratorio. Só tiña 14 anos cando comecei, pero non deixei que isto fose un atranco para teimar na miña investigación e no desexo de resolver a crise mundial da auga.
See, water isn't just the universal solvent. Water is a universal human right. And for that reason, I'm continuing to work on this science fair project from 2012 to bring it from the laboratory into the real world. And this summer, I founded Catalyst for World Water, a social enterprise aimed at catalyzing solutions to the global water crisis.
A auga non só é o solvente universal. É tamén un dereito humano universal. Por iso sigo traballando naquel proxecto escolar de 2012, para trasladar á sociedade esa investigación. E este verán fundei a Catalizadora da Auga do Mundo, unha empresa social enfocada en catalizar solucións para a crise global da auga.
(Applause)
(Aplausos)
Alone, a single drop of water can't do much, but when many drops come together, they can sustain life on our planet. Just as water drops come together to form oceans, I believe that we all must come together when tackling this global problem.
Unha soa pinga no océano non é gran cousa, pero todas elas xuntas son a base da vida no planeta. Dese mesmo xeito deberiamos xuntarnos todos para afrontar o problema da auga no mundo.
Thank you.
Grazas.
(Applause)
(Aplausos)
Thank you.
Grazas.
(Applause)
(Aplausos)