Removal of Heavy Metals from Contamined Aquifers by Vegetable Fibers. Comparisons among Cabuya Fibers, Broom Fibers and ZVI

Abstract

The growing contamination of groundwater requires increasingly remediation. Among the different reclamation techniques of contaminated aquifers, recourse is frequently made to permeable reactive barriers (PRB). To build such barriers Zero Valent Iron (ZVI) is commonly used, which shows a good reactivity towards the most part of the heavy metals. However, owing to economic reasons, and to some problems that this substance produces, reactive substances usable in alternative to zero valent iron are constantly being researched. The present study takes into account the fibers of a vegetable substance, the cabuya, investigating its capacity to retain heavy metals. Specifically, among these, Copper (Cu), Zinc (Zn), Lead (Pb) and Cadmium (Cd) were considered. The capacity of the fibers of cabuya to absorb heavy metals was verified in the laboratory, at first by batch tests and later by appropriate column tests. The same tests were carried out using also Zero Valent Iron. The results obtained for the cabuya vegetable fibers, showed a very high adsorption capacity of heavy metals and resulted very comparable to that of ZVI, without, however, showing the negative aspects of the latter. Some comparisons were also carried out with broom fibers, investigated in a previous study.