Genitivo e dativo in leponzio. A proposito di una nuova iscrizione.

<div><p>Base metal tailings (BMTs) are normally sulfidic and contain high abundance of residue metals. Their adverse impacts on the environment can last for decades to centuries if without appropriate stabilization. While in situ phytostabilization has been thought to be a promising approach to stabilize surface tailings, few studies have reported success in constructing a sustainable plant community in BMTs so far, implying that a new paradigm involving a sophisticated understanding of the nature of BMTs is needed for BMTs phytostabilization. Using a property database of BMTs worldwide built in this study as a backdrop, this review explores how BMTs are different from normal soils and how these differences influence the strategies of BMTs phytostabilization. It is found that BMTs are mineralogically and chemically different from natural soils, which endows BMTs with unstable geochemistry and inherent extreme toxicity. Studies have documented that amendment options and soil development in BMTs phytostabilization are largely constrained by these abiotic factors. From a viewpoint of pedogenesis, BMTs can be seen as novel parent materials rather than soil. Accordingly, we propose that in BMTs phytostabilization, extensive engineering efforts are required to increase the biocapacity of tailings (i.e., anthropogenic pedogenesis) rather than focus on the selection and establishment of plants.</p></div

Phosphate sorption isotherms in the tailings and HS soil, which were fitted with Langmuir equation (see Table 3).

<p>The values were averages of 3 replicates at each P-concentration and the bars indicate corresponding standard deviation.</p

The particle size distribution of the tailings samples and HS soil sample.

<p>The particle size distribution of the tailings samples and HS soil sample.</p

The presence of major primary and secondary minerals identified in the tailings and soil samples by XRD-analysis.

<p>The presence of major primary and secondary minerals identified in the tailings and soil samples by XRD-analysis.</p

Extremely High Phosphate Sorption Capacity in Cu-Pb-Zn Mine Tailings

<div><p>Elevated inorganic phosphate (Pi) concentrations in pore water of amended tailings under direct revegetation may cause toxicity in some native woody species but not native forbs or herb species, all of which are key constituents in target native plant communities for phytostabilizing base metal mine tailings. As a result, Pi sorption capacity has been quantified by a conventional batch procedure in three types of base metal mine tailings sampled from two copper (Cu)-lead (Pb)-zinc (Zn) mines, as the basis for Pi-fertiliser addition. It was found that the Pi-sorption capacity in the tailings and local soil was extremely high, far higher than highly weathered agricultural soils in literature, but similar to those of volcanic ash soils. The Langmuir P-sorption maximum was up to 7.72, 4.12, 4.02 and 3.62 mg P g^-1 tailings, in the fresh tailings of mixed Cu-Pb-Zn streams (MIMTD7), the weathered tailings of mixed Cu-Pb-Zn streams (MIMTD5), EHM-TD (fresh Cu-stream, high magnetite content) and local soil (weathered shale and schist), respectively. Physicochemical factors highly correlated with the high Pi-sorption in the tailings were fine particle distribution, oxalate and dithionite-citrate-bicarbonate extractable Fe (Fe_O and Fe_d), oxalate-extractable Al and Mn, and the levels of soluble Cd and Zn, and total S and Fe. Large amounts of amorphous Fe oxides and oxyhydroxides may have been formed from the oxidation of pyritic materials and redox cycles of Fe-minerals (such as pyrite (FeS₂), ankerite (Ca(Fe Mg)(CO₃)₂ and siderite (FeCO₃), as indicated by the extractable Fe_O values. The likely formation of sparingly soluble Zn-phosphate in the Pb-Zn tailings containing high levels of Zn (from sphalerite ((Zn,Fe)S, ZnS, (Zn,Cd)S)) may substantially lower soluble Zn levels in the tailings through high rates of Pi-fertiliser addition. As a result, the possibility of P-toxicity in native plant species caused by the addition of soluble phosphate fertilizers would be minimal.</p></div

Control Preparation of Zinc Hydroxide Nitrate Nanocrystals and Examination of the Chemical and Structural Stability

We have investigated the control preparation and aqueous stability of a potential suspension fertilizer: zinc hydroxide nitrate. We have observed that this compound can be synthesized by quick precipitation of zinc nitrate in sodium hydroxide solution under various conditions, whereas it can also be readily transformed to more stable Zn­(OH)₂ or ZnO at pH >6.5 and aged at 50 °C. The transformation from zinc hydroxide nitrate to Zn­(OH)₂ and ZnO has been examined with XRD/FTIR/SEM techniques and discussed in detail, presumably involving the formation and dissociation of the intermediate solution species [Zn­(OH)₄]^2–/[Zn­(OH)₃]⁻. We have also found that as-prepared zinc hydroxide nitrate crystals are very stable when they are isolated and then dispersed in aqueous solution with pH 5–9 while slightly dissolved to give zinc ion concentration of 30–50 mg/L. Such aqueous stability and solubility have thus suggested that this compound can be used as a long-term zinc foliar fertilizer of various crops

Nitrogen-Rich Organic Matter Formation and Stabilization in Iron Ore Tailings: A Submicrometer Investigation

Organic matter (OM) formation and stabilization are critical processes in the eco-engineered pedogenesis of Fe ore tailings, but the underlying mechanisms are unclear. The present 12 month microcosm study has adopted nanoscale secondary ion mass spectrometry (NanoSIMS) and synchrotron-based scanning transmission X-ray microscopy (STXM) techniques to investigate OM formation, molecular signature, and stabilization in tailings at micro- and nanometer scales. In this system, microbial processing of exogenous isotopically labeled OM demonstrated that 13C labeled glucose and 13C/15N labeled plant biomass were decomposed, regenerated, and associated with Fe-rich minerals in a heterogeneous pattern in tailings. Particularly, when tailings were amended with plant biomass, the 15N-rich microbially derived OM was generated and bound to minerals to form an internal organo-mineral association, facilitating further OM stabilization. The organo-mineral associations were primarily underpinned by interactions of carboxyl, amide, aromatic, and/or aliphatic groups with weathered mineral products derived from biotite-like minerals in fresh tailings (i.e., with Fe2+ and Fe3+) or with Fe3+ oxyhydroxides in aged tailings. The study revealed microbial OM generation and subsequent organo-mineral association in Fe ore tailings at the submicrometer scale during early stages of eco-engineered pedogenesis, providing a basis for the development of microbial based technologies toward tailings’ ecological rehabilitation

Selective Extraction of Critical Metals from Spent Lithium-Ion Batteries

Selective and highly efficient extraction technologies for the recovery of critical metals including lithium, nickel, cobalt, and manganese from spent lithium-ion battery (LIB) cathode materials are essential in driving circularity. The tailored deep eutectic solvent (DES) choline chloride–formic acid (ChCl–FA) demonstrated a high selectivity and efficiency in extracting critical metals from mixed cathode materials (LiFePO4:Li(NiCoMn)1/3O2 mass ratio of 1:1) under mild conditions (80 °C, 120 min) with a solid–liquid mass ratio of 1:200. The leaching performance of critical metals could be further enhanced by mechanochemical processing because of particle size reduction, grain refinement, and internal energy storage. Furthermore, mechanochemical reactions effectively inhibited undesirable leaching of nontarget elements (iron and phosphorus), thus promoting the selectivity and leaching efficiency of critical metals. This was achieved through the preoxidation of Fe and the enhanced stability of iron phosphate framework, which significantly increased the separation factor of critical metals to nontarget elements from 56.9 to 1475. The proposed combination of ChCl–FA extraction and the mechanochemical reaction can achieve a highly selective extraction of critical metals from multisource spent LIBs under mild conditions

Organic Matter Amendment and Plant Colonization Drive Mineral Weathering, Organic Carbon Sequestration, and Water-Stable Aggregation in Magnetite Fe Ore Tailings

The formation of water-stable aggregates in finely textured and polymineral magnetite Fe ore tailings is one of the critical processes in eco-engineering tailings into soil-like substrates as a new way to rehabilitate the tailings. Organic matter (OM) amendment and plant colonization are considered to be effective in enhancing water-stable aggregation, but the underlying mechanisms have not yet been elucidated. The present study aimed to characterize detailed changes in physicochemistry, Fe-bearing mineralogy, and organo-mineral interactions in magnetite Fe ore tailings subject to the combined treatments of OM amendment and plant colonization, by employing various microspectroscopic methods, including synchrotron-based X-ray absorption fine structure spectroscopy and nanoscale secondary ion mass spectroscopy. The results indicated that OM amendment and plant colonization neutralized the tailings’ alkaline pH and facilitated water-stable aggregate formation. The resultant aggregates were consequences of ligand-promoted bioweathering of primary Fe-bearing minerals (mainly biotite-like minerals) and the formation of secondary Fe-rich mineral gels. Especially, the sequestration of OM (rich in carboxyl, aromatic, and/or carbonyl C) by Fe-rich minerals via ligand-exchange and/or hydrophobic interactions contributed to the aggregation. These findings have uncovered the processes and mechanisms of water-stable aggregate formation driven by OM amendment and plant colonization in alkaline Fe ore tailings, thus providing important basis for eco-engineered pedogenesis in the tailings