Cd-contaminated solution treatment by activated and non-activated beech charcoal

Biochar obtained from pyrolysis of vegetable waste has been recognized to possess adsorbent capacity. Furthermore, it represents an economic and environmentally sustainable alternative to commercial adsorbents because, being a waste product, its use allows to avoid industrial activities for adsorbent production as well as to reduce the amount of waste to be disposed of. In this paper, the biochar produced by pyrolysis of beech has been investigated as a potential adsorbent for remediation of cadmium-contaminated groundwater. So far, beech charcoal has been mainly used as a soil amendment and only few experiences have been reported about its use as an adsorbent medium. The present experimental activity started with a series of analyses to obtain the main physical-chemical characteristics of charcoal. Adsorption kinetics and isotherms through batch experiments were then determined. Furthermore, breakthrough curves were obtained through column experiments. The same tests were repeated using the beech charcoal after modification through the addition of specific bacterial strains able to produce a reactive monolayer biofilm. The results showed that bio-activated charcoal has enhanced adsorption capacity for cadmium-contaminated solution. Therefore, charcoal and bio-activated charcoal may be considered valid options as adsorbents for the remediation of solution contaminated by cadmium.