Sydney University Chemical Engineering

During the first week of August 2018, I was given a place in the Chemical Engineering Work Experience program hosted by the University of Sydney. It was such a unique opportunity as I got to learn about the varying topics of research from PhD students and to assist them in a typical week, and to experience through hands-on activities the real-world applications of science.

These activities included trying out Spray Drying, creating Carbon Quantum Dots, and many other workshops on topics such as membranes and osmosis, hydrogen fuel cell cars, and algae growth modelling. On the last day, our group of Year 10 students were also treated to a workshop making ice cream using liquid nitrogen!

Spray Drying

Spray Drying is a method to instantly dry a solution to powders of the same size. During this workshop, we first made a solution with lactose and sucrose by combining them with water, and then spray dried them into powder form. Then, through dissolving and centrifuging the sucrose using ethanol, a porous structure was made. By loading drugs into this structure, it allows for the chemicals to crystalise to a smaller scale, hence improving the absorption of the chemicals in medicine.

A spray dryer works in three steps. First, the solution is atomised for controlled size of particles. It is then dried in hot air, and finally collected in a recovery process

Carbon Quantum Dots

Carbon Quantum Dots were made through the reaction between urea and citric acid in a fume-hood, given heat. This creates a liquid mixture, which is then carefully transferred into dialysis bag that only allows fine particles to pass through.

From the dialysis bag, only particles under 10 nm are collected as "Carbon Quantum Dots", or "C-dots" for short. As the C-dots glow under UV light, this has led to applications such as bio-imaging and controlled drug delivery.

Membranes

In this workshop session, we compared commercialized membrane with self made membrane from USyd on their ability to perform forward osmosis between salt water and pure water. The aim was to find the most optimal membrane production process.

For membranes from the University of Sydney, a polymer solution was made and spread on glass plates. It was solidify with cold water, but further research showed that the membranes are more effective if it's solidified with 25% ethanol.

Applications of membrane include desalination, for example. Because sea water has a higher concentration density than pure water, currently a huge amount of power is needed in order to perform reverse osmosis (to convert salt water back to water). However, if there's a way to make a solution (so that forward osmosis can take place between salt water and the solution) which then can be easily converted to pure water, or can be consumed harmlessly after the osmosis, it would save large amounts of energy going into desalination plants.