Contrary to what one might think from reading this blog, which is full of weekend stories and social interactions, my purpose for pursuing a graduate degree at KAUST is not to have fun in Saudi Arabia, sight-see in the Middle East, get paid a graduate stipend, or learn Arabic. I am not even in school to attend classes - mixed or unmixed - though I have been mostly satisfied with quality of the lectures so far. I was recruited to KAUST, along with so many other students, staff, and faculty, to do research in hope of discovering new things. I haven't said much about research on this blog for two reasons: (1) biological research was a little slow in getting started at KAUST and (2) I don't think you have the patience and the enthusiasm to read dozens of blog entries about my daily work.
My research project, however, is pretty unique and I'll try not to bore you with too many details. I am working with a small research team to develop microbial fuel cell (MFC) which harnesses bacteria's metabolism to produce small amounts of electricity from sugar and other carbon sources. MFC technology has potential to be used in wastewater treatment, but there are still many challenges to implementing this technology on an industrial scale.
This is a simplified drawing of the MFC process, taken from a research article by Bruce E. Logan et al published in 2006. An MFC has two electrodes - an anode and a cathode. Bacteria growing on the anode donate electrons to the circuit if there is a voltage difference between the anode and the cathode. The voltage difference is created by an electron acceptor at the cathode, which can be oxygen, iron, nitrate, or any of a number of elements. The membrane is a barrier which prevents the electron acceptor from diffusing from the cathode to the anode, but allows ions, such as hydrogen, which are byproducts of the bacteria's metabolism, to pass from the anode to the cathode.
Microbial fuel cells can be modified by including a third chamber for salt water, and used to desalinate water without adding any heat or electricity - in fact there is still a small net electricity production in this laboratory demonstration. This reactor is called a Microbial Desalination Cell (MDC). The picture here is taken from a research article by Xiaoxin Cao et al, published in 2009. Salt (sodium chloride) is removed because of a chemical potential difference. Negatively charged ions, such as chlorine, migrate to the anode, while positively charged ions, such as sodium, migrate to the cathode. As ions migrate, the water in the middle chamber becomes purer.
These are not mature technologies and there is no 100% guarantee that MFC and MDC technology will be appropriate for water reuse and desalination in the future. There are still many challenges with bacterial community stability, sustainable cathode design, and scale-up losses. However, MFC and MDC technology is versatile and I am excited to work in a new and potentially promising field. If some small thing that I do at KAUST can someday lead to making more fresh water available for people in countries that need it, I will consider my time and efforts here to have been well spent.