Feasibility Study on Reducing Lead and Cadmium Absorption by Alfalfa (Medicago scutellata L.) in a Contaminated Soil Using Nano-Activated Carbon and Natural Based Nano-Zeolite

The first risk posed by heavy metal pollution in an ecosystem is metal accumulation in the biomass of growing plants, which has harmful effects on human health. Natural-based nanoparticles are efficient in remediating environmental pollutants because they have a high surface/volume ratio, high chemical activity and produce no harmful side-products. The present study investigates the capacity of natural-based nano-porous adsorbents for reducing the availability of heavy metals to annual alfalfa (Medicago scutellata L.) roots and keeps them in soil. In a factorial experiment based on a randomized design (with four replications), three nano-adsorbents (nano-activated carbon, natural nano-zeolite and modified nano-zeolite) and two heavy metals (lead and cadmium) have been tested. The results demonstrated that applying the highest rate of activated carbon and modified nano-zeolite reduced shoot Pb content by 34% and 33.2%, and shoot Cd content by 35.5% and 46.7%, respectively, compared with the adsorbent-free control.