Immobilization of Potentially Toxic Elements in Contaminated Soils Using Thermally Treated Natural Zeolite

Abstract

Rehabilitation of contaminated soils is a complex and time-consuming procedure. One of the most cost-effective and easy-to-use soil remediation approaches is the use of amendments that stabilize the potential toxic elements (PTE) in soil by reducing their mobility and bioavailability. The stabilization of Cu, Pb, Zn, Cd, Co, Cr, Ni in a contaminated soil using 5% and 10% amendment with thermally treated natural zeolite was investigated using a sequential extraction procedure, contamination and environmental risk factors. The results showed that after amendment, the PTE concentration decreased in the exchangeable and reducible fractions and increased in the oxidizable and residual fractions. The highest immobilization effect, consisting in the decrease of exchangeable fractions with 69% was obtained in case of 10% zeolite amendment and 90 days of equilibration time for Pb; also, more than half of the mobile fraction was immobilized in case of Zn, Cu, and Co and about one third in case of Ni, Cr, and Cd. Generally, the immobilization effect of the 5% and 10% amendment is comparable, but a higher equilibration time enhanced the immobilization effect, especially in the case of Cd, Co, Cu, Pb, and Zn.

Modification of natural zeolites and their applications for heavy metal removal from polluted environments: Challenges, recent advances, and perspectives

“…However, Kuldeyev et al [ 98 ] reported high adsorption capacities (94–98 %) for Cd, Ni and Pb from heavily polluted waters, using natural zeolites with a particle size of 3 mm, thermally treated at 500 °C in an inert atmosphere. A higher immobilization effect for heavy metals was reported using 10 % thermally treated natural zeolite at 200 °C for 2 h as soil amendment [ 130 ] compared with air-dried zeolitic material [ 94 ].…”

Metal Contents and Pollution Indices Assessment of Surface Water, Soil, and Sediment from the Arieș River Basin Mining Area, Romania

“…Samples were digested using a Speedwave XPERT (Berghof, Eningen, Germany) microwave digestion system with HNO 3 65% in the case of water samples and aqua regia (HNO 3 65%:HCl 37% (v/v) = 1:3) in the case of solid (soil and sediment) samples [29]. Fe, Na, Mg, K, and Ca were determined using a 5300 Optima DV (PerkinElmer, MA, USA) Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), while Ni, Cr, Cu, Zn, Cd, Pb, Mn, Al, and As were determined with an ELAN DRC II Inductively Coupled Mass Spectrometer (PerkinElmer, MA, USA).…”

Zeolites: A potential strategy for the solution of current environmental problems and a sustainable application for crop improvement and plant protection

“…Thus, since 2010, agriculture has already destroyed or radically transformed 70% of grasslands, 50% of savannas, 45% of temperate deciduous forests and 25% of tropical forests [18]. Against these volumes, the increase in production has been only 20% [19]. With the felling of tropical forests, the exploitation of marginal lands and the use of intensive techniques, agriculture has become the planet's main environmental threat, consuming a large percentage of the earth's surface, destroying habitats, depleting water resources, polluting rivers and oceans and being one of the main (24%) sources of anthropogenic greenhouse gas emissions [20].…”