Irrigating Melissa officinalis L. Medicinal Plant with Chromium Wastewater Treated by Electrocoagulation

In recent decades, enormous use of chromium in different industries as well as water and soil pollution by those industries caused serious concern. Toxic impact of chromium on the growth of plants includes changes in the process of germination and root, stem and leaves’ growth. Chromium also has harmful impact on the plants’ physiological processes such as photosynthesis. On the other hand, iron is one of the essential elements for the growth of plants without which enough chlorophyll would not exist in the cells, consequently; making leaves pale. Melissa officinalis L. is an herb with 30 to 120 cm long. This plant is sensitive to iron deficiency. Electrocoagulation is a method to remove heavy metals. One of the advantages of this method is low consumption of power and high efficiency in removing pollutants. In this study chromium removal with 500 mg/l concentration from artificial wastewater containing chromium (III) was examined and removal efficiency of 97% was achieved. Here also the impact of pH on efficiency of chromium removal and amount of produced iron was tested and voltage parameter was examined to achieve optimal condition. In regard to efficiency of chromium removal, the optimal pH of tests was 6 and the amount of iron was 8.14 mg/l.