We describe a 2 h general-chemistry experiment that introduces college students not only to the concepts, synthesis, and applications of nanomaterials at an early stage but also the use of a spectrophotometer for quantification and unknown determination based on Beer's Law. The procedure involves students (1) preparing a nanocomposite by chemically incorporating magnetite nanoparticles into activated carbon (AC), (2) using the as-prepared nanocomposite to treat an aspirin "metabolite" solution for 5 min, and (3) spectroscopically evaluating the nanocomposite's removal efficiency for this "pollutant". The spectroscopic measurement is based on a colored complex the pollutant forms with an acidified iron(III)-ion solution. The nanocomposite is magnetically recovered from treated water and is found to remove 90−130 mg of equivalent aspirin mass per gram of AC. The experiment, using commonly available chemicals and equipment, has been performed by 190 students in groups of two to three and is well-received and enjoyed by these students.

A bifunctional magnetic Fe3O4@SiO2@TiO2 or MS-TiO2 antimicrobial nanocomposite was prepared based on simple sol-gel methods with common equipment and chemicals. Reaction pH was found to influence the TiO2 upload in the nanocomposite. The alkaline condition produced the greatest TiO2 upload, while the acidic condition the least. Annealing at 300 °C turned the as-synthesized amorphous TiO2 into one with high content of anatase, the most photoactive form of TiO2. Irradiated by 365 nm UV light, a sample of 30 mg/mL of annealed nanocomposite containing 12.6 wt.% Ti was shown to be able to completely eradicate 104 CFU/mL of the laboratory-grown E. coli within 25 min, 25 min faster than the control when the 365 nm UV light was employed alone. The nanocomposite demonstrated consistent antimicrobial performance over repeated uses and was easily recoverable magnetically due to its high magnetization value (33 emu/g). Additionally, it was shown to reduce the bacterial count in a real surface water sample containing 500–5000 CFU/mL of different microbes by 62 ± 3% within 30 min. The irradiating 365 nm UV light alone was found to have generated little biocidal effect on this surface water sample. The nanocomposite is promising to serve as an effective, safe, and eco-friendly antimicrobial agent, especially for surface water disinfection.