Removal of Transition Metals from Contaminated Aquifers by PRB Technology: Performance Comparison among Reactive Materials.

Celia Margarita Mayacela-Rojas,Oriol Gibert,José Luis Cortina,Adalgisa Tavolaro,Carmine Fallico,Carlos Ayora,María Fernanda Rivera-Velásquez,Antonio Molinari

doi:10.3390/ijerph18116075

Abstract

The most common reactive material used for the construction of a permeable reactive barrier (PRB) is zero valent iron (ZVI), however, its processing can generate corrosive effects that reduce the efficiency of the barrier. The present study makes a major contribution to understanding new reactive materials as natural and synthetic, easy to obtain, economical and environmentally friendly as possible substitutes for the traditional ZHV to be used as filters in the removal of three transition metals (Zn, Cu, Cd). To assess the ability to remove these pollutants, a series of batch and column tests were carried out at laboratory scale with these materials. Through BACH tests, four of seven substances with a removal percentage higher than 99% were prioritized (cabuya, natural clinoptilolite zeolites, sodium mordenite and mordenite). From this group of substances, column tests were performed where it is evidenced that cabuya fiber presents the lowest absorption time (≈189 h) while natural zeolite mordenite shows the highest time (≈833 h). The latter being the best option for the PRB design. The experimental values were also reproduced by the RETRASO code; through this program, the trend between the observed and simulated values with respect to the best reactive substance was corroborated.

Highlights

Most of the world’s water needs are satisfied by groundwater, which makes up about96% of the entire water supply of our planet [1] and which is often the only source of fresh water supply, especially in arid and semi-arid regions
The simulation by the reactive solids transport numbering code (RETRASO) code was made for all the selected reactive materials and considering all the transition metals taken into consideration (Zn, Cu and Cd), using
On the basis of the results obtained for the reactive materials investigated with the column tests, their behavior was extrapolated for a permeable reactive barrier (PRB) with a thickness of 1 m and unitary section

Summary

Introduction

Most of the world’s water needs are satisfied by groundwater, which makes up about96% of the entire water supply of our planet [1] and which is often the only source of fresh water supply, especially in arid and semi-arid regions. The interaction with groundwater generated by multiple anthropogenic activities, especially agricultural and industrial, often produces pollution and degradation of its quality, which in many cases leads to a high risk for human health. In this context, the presence in groundwater of transition metals is dangerous. Transition metal contamination is mainly produced by industrial activities, as well as by numerous other forms of interaction between anthropic activities and the environment (waste production, combustion of hydrocarbons, vehicular traffic, use of pesticides and others). Transition metals are toxic and/or carcinogenic species, with.

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