Modifying Clay-Based Germicidal Filters to Remove Harmful Metal Ions from Water

Clay filters treated with silver nanoparticles have shown strong germicidal activity. However, other toxins in water include heavy metal ions from agricultural runoff. This investigation deals with possible amendments to the clay filter, allowing it to not only kill bacteria but also remove heavy metal ions from water. Copper, a common heavy metal in fungicides, was used in this investigation. Absorbance was measured in the visible range for three different copper solutions (CuSO4, CuCl2 and Cu(NO3)2). The solutions were funneled through three different mineral compounds (activated carbon, bentonite and zeolite) that have shown promise in previous studies. The absorbance data were used to determine the reduction in concentration. Various amounts of these compounds were used. Activated carbon and bentonite did not lower copper levels. Zeolite significantly reduced the concentration (26% less absorbance) of Cu(NO3)2 consistently, but its effect on the others remains unclear. Further testing is ongoing to confirm and extend the zeolite results. One extension includes baking zeolite into the clay filter. Zeolite is the most promising of the tested compounds so far, but further testing is needed to ensure that its effect is a result of the copper and not the nitrate counter ion