Zinc-reinforced ZSM-5 subject to a rare-earth magnet and the presence of a legume yields substantial copper extraction

Abstract

Adsorption, using chemically modified zeolites, is a common conventional method of mitigating heavy metal pollution. However, the physical modification of zeolites with reducing agents subject to static magnets and biological trappers is yet to be explored. In this laboratory-based work, we partly gel-coated raw ZSM-5 pellets with zinc coarse powder and tested their performance in copper extraction from a polluted medium with copper sulfate. We also examined the performance subject to the presence of a neodymium magnet, with and without faba bean, Vicia faba, as a copper bio-trap. Additionally, on a limited scale, we plasma-sputtered ZSM-5 pellets with zinc and tested their copper extraction under the magnet effect. Inductively coupled plasma mass spectrometry (ICP) revealed that the reinforced zeolite led to the fastest copper extraction, outperforming the raw zeolite and the bio-trap, especially as time advanced. Accompanying the reinforced zeolite with the bio-trap was the most effective over time, followed by having both the magnet and the bio-trap to accompany the reinforced zeolite. However, interestingly, having the magnet as a sole companion of the reinforced zeolite was always better than using raw zeolite, but slightly of a lesser yield than having the reinforced companionless. The bio-trap was a better companion than the magnet, but after 20min having both companions was more beneficial than having the magnet alone and less yielding than having the bio-trap solo in the long term, indicating a synergistic effect between the reinforced zeolite and the bio-trap. Brunauer, Emmett and Teller (BET), Energy-Dispersive X-ray Spectroscopy (EDAX), and X-ray diffraction analyses, provided supportive information that underscored the stability yet the differential performance of ZSM-5. Although the extraction efficacy deteriorated sharply over time, the zinc-sputtered zeolite showed promising early results, exceeding those of the raw and the reinforced zeolites when the magnet was absent and almost identical to the outcome when the magnet accompanied the reinforced zeolite. Our amalgamative approach provides user-friendly novel methods of notable copper extraction, with high applicability potential for the extraction of other heavy metals from aquatic media.