Cola beverages are widely consumed and popular among students; they can be used as safe reagents to replace toxic chemical dyes. In this study, a safe and improved experiment is described, which successfully demonstrates Beer's law and adsorption process using activated carbon as the adsorbent and cola as the adsorbate. The results of this study demonstrate that the use of cola has achieved good evaluation for the teaching of the Beer's law and the adsorption phenomenon. The potential learning outcomes of the experiment include the principles of spectrophotometry, operation of spectrophotometer, Beer's law and its limitations, derivation of linear regression equation, and construction of adsorption isotherms. This experiment can be used as a safe spectrophotometric protocol to determine the adsorption isotherms for undergraduate learning of analytical or general chemistry.

In this work, modified nano-mesh structured Mn-based oxide electrode material and the supercapacitors are researched. Three types of conducting polymers, i.e. polyaniline (PANI), polypyrrole (PPy) and polythiophene (PTs) are considered to modify Mn-based oxide electrodes. The results of field emission scanning electron microscope show that conducting polymer film can form porous structure on Mn-based oxide electrode, this special structure is beneficial to the improvement of specific surface area, so that the specific capacitance can be increased. The specific capacitance of the supercapacitors assembled by Mn-based oxide/conducting polymer composite electrodes are tested, resulting that the maximum initial specific capacitance is 843 F g-1, cycle life is 105 times. Compared to supercapacitors assembled by general Mn-based oxide electrodes, this Mn-based oxide/conducting polymer material electrode can improve the specific capacitance up to 1.4~1.9 times, and the conductivity and cycle stability can be increased at the same time.