Research Topic 101 – Adsorption
Adsorption is a popular category of STEM research in high school. Basically, it’s used to separate particles—usually pollutants—from a liquid solution. These studies usually focus on removing heavy metals from wastewater.
When pursuing adsorption, aim to have novel elements in your study. Otherwise, review the literature and aim to build on top of that information.
If you want to have a good start with your adsorption research, here are some important things to keep in mind:
- Specify the type of adsorption. Is it physical adsorption? Or is it chemical adsorption?
- Physical adsorption (physisorption) happens when a pollutant particle is attracted to your adsorbent material. If there is a chemical reaction involved, this is called chemical adsorption (chemisorption).
- Specify the dosage. Here, dosage means the grams of adsorbent per milliliter of solution (g/mL). The amount of removed pollutants will depend on the amount of adsorbent you will put.
- Specify the adsorption conditions. Temperature, adsorption time, adsorbent particle size, pH, and agitation speed all affect the level of adsorption. You can measure particle size by using calibrated “sieves”, and pH by using calibrated pH electrodes. Temperature, time and speed can be set on the equipment you will use.
If you want to level up your research, consider the following:
- Don’t just report the percent removal of pollutant. Present the value qe, which is the equilibrium adsorption capacity, and qt, the adsorption capacity at a time t. These values are used to generate graphs about the level of adsorption versus time.
- Explore the adsorption isotherms. These are theories to describe the types of adsorption. Read up on the Languir model, the Freundlich model, and the BET (Brunauer, Emmett, and Teller) model.
- Read up on the pseudo-order kinetics of adsorption. These can describe how fast your adsorption is happening.
And finally, since adsorption studies will require mathematical modeling and generating calibration curves, be mindful of proper data collection and processing, or increase the amount of runs you will do.
Modeling for isotherms and kinetics can be done in spreadsheet programs like Excel, but be aware that errors will be larger in Excel due to linearization. If you are able, consider using statistical software such as RStudio.
REMEMBER:
Specify the type of adsorption.
Specify the dosage and the adsorption conditions.
Report the adsorption capacity (qe) and present graphs in your study.
Explore the adsorption isotherms and pseudo-order kinetics.
Tanim Talino 