Genius teens offer clever exhast emissions fix

Albany Senior High School (ASHS) Year-13 students Alec Wang (left) and Jun Bing were chosen as semi-finalists in the inaugural Google Global Science Fair. Photo / Supplied

Two North Shore City high-school students have caught the attention of the world's scientific community with an invention that cleans greenhouse gases out of car exhausts.

Albany Senior High School Year 13 students Alec Wang and Jun Bing were chosen as semi-finalists in the inaugural Google Global Science Fair (GSF), earning one of just 60 places from more than 7500 initial entries.

Alec and Jun were the only New Zealand entrants to be chosen.

The device, which was submitted under the title "A Working Model of a Device Capable of Filtering out Carbon Dioxide from Car Exhausts", employs a two-stage filtration process that can remove more than 90 per cent of greenhouse gases from car-exhaust emissions.

Alec said the impetus for the project was simple: "We were both interested in using science to create something worthwhile."

By finding a way to remove C02 from the exhaust systems of cars with conventional internal combustion-engine technology, the boys say such a system could "buy time" for the car industry to continue developing next-generation powertrains without further contributing to global warming.

To be acknowledged by the GSF in this way is an incredible achievement - even when you consider that the boys had a pretty good head start.

By the time entries opened on January 11, Alec and Jun had invested more than 700 hours in the project.

It started three years ago under the school's Impact Learning programme, through which students are able to pursue an independent project for one day each week. The project was also fostered through the Royal Society of New Zealand, an organisation which promotes science, technology and the humanities. The society offers students a programme called Crest: Alec and Jun were able to move their filtration research and development forward through the Silver Crest (for projects taking three to four terms) and Gold Crest (for four- to six-term projects).

"By the time our teacher showed us the details for the Google Science Fair, the timeline fitted in quite well," says Alec. "We had completed quite a lot of our work and we were ready."

Alec and Jun settled on a "bubbling" technique that forces the exhaust gas through a two-stage filtration system.Jun's device creates a carbonic acid reaction in exhaust gas using alkaline sodium hydroxide solution to create sodium carbonate and water. This process is known as an "acid base neutralisation reaction" and is the primary chemical mechanism for sequestering CO2 gas.

After experimenting with different application methods, including spraying the solution on to the exhaust gas, the pair settled on a "bubbling" technique that forces the exhaust gas through a two-stage filtration system.

Two linked canisters are filled with fine sponge and sodium hydroxide solution, giving excellent filtration but also allowing large volumes of gas to pass through.

Tests carried out on a 1996 Mazda Sentia - which was revved to 2000rpm, its emissions captured and analysed using a CO2 sensor - proved that the system removed 90.42 per cent of CO2 from the car's exhaust.

There was not a lot of personalised feedback from the GSF judges - not surprising when you consider the volume of entries. But Alec and Jun said their project made the semi-finals because it was a unique idea, the research was well categorised and they followed a scientific process.

Unfortunately, the boys didn't make it through to the next round of 15 finalists. So for now they'll have to be content with being in the top 1 per cent of global science students.

Will they attempt to take the project further on their own?

"This is a really rough design - it's just to prove that this technology could be used on a car," says Alec.

"It works but the big problem is that it doesn't last very long. You would go through the storage capacity of our device in a couple of hours.

"To make it effective we would need more funding and more time to miniaturise the system and make it last longer. But if we could upgrade and integrate it into a vehicle, we could prevent existing cars from creating more global warming."