Abstract
The use of rare earth elements is a growing trend in diverse industrial activities, leading to the need for eco-friendly approaches to their efficient recovery and reuse. The aim of this work is the development of an environmentally friendly and competitive technology for the recovery of those elements from wastewater. Kinetic and equilibria batch assays were performed with zeolite, with and without bacterial biofilm, to entrap rare earth ions from aqueous solution. Continuous assays were also performed in column setups. Over 90% removal of lanthanum and cerium was achieved using zeolite as sorbent, with and without biofilm, decreasing to 70% and 80%, respectively, when suspended Bacillus cereus was used. Desorption from the zeolite reached over 60%, regardless of the tested conditions. When in continuous flow in columns, the removal yield was similar for all of the rare earth elements tested. Lanthanum and cerium were the elements most easily removed by all tested sorbents when tested in single- or multi-solute solutions, in batch and column assays. Rare earth removal from wastewater in open setups is possible, as well as their recovery by desorption processes, allowing a continuous mode of operation.
Highlights
The evolution of industrial activity over the last two centuries has led to various problems, such as an increasing need for consumption, accumulated pollution, and foreseen climate change
This makes it possible to assess the xenobiotic effect of each element on the bacteria B. cereus, and possibly to evaluate the sensitivity of the bacteria towards the tested elements
Theisaverage pore size foras the zeolite was performed, the results presented in Table microporous solid, the micropore performed, and the results in is solid, as performed,and and the results are are presented presented in Table is aa microporous microporous solid, as the the performed, and the results are presented in is a microporous solid, as the volume corresponds to more than of the total pore volume
Summary
The evolution of industrial activity over the last two centuries has led to various problems, such as an increasing need for consumption, accumulated pollution, and foreseen climate change. In parallel, this evolution has enabled the development of new technologies to tackle the problems raised [1,2]. Most transformation and production processes imply a resource deficit, as is the case with rare earth elements (REE) and precious metals [2]. REE contribute to important production sectors, including in the mundane (fluorescent lamps), high-tech (batteries, lasers, super-magnets) and futuristic (high-temperature superconductivity, information storage, conservation and transport of energy) fields, due to their diverse chemical, electrical, metallurgical, magnetic, optical and catalytic properties [5,6,7]. Countries like China, the United States of America and Australia are the Molecules 2019, 24, 1005; doi:10.3390/molecules24061005 www.mdpi.com/journal/molecules
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
