Elio Coppola

Remediation of Cd- and Pb-polluted soil by treatment with organo-zeolite conditioner

The present work is part of a study focused on the use of organo-zeolite conditioner to remediate soil polluted by toxic elements. The Neapolitan yellow tuff (NYT) was utilized as a component of an organo-mineral sorbent/exchanger soil conditioner with pellet manure (NYT/PM) to reduce the mobility of Cd and Pb and recover plant performance in heavily polluted soils from illegal dumps near Santa Maria La Fossa (Lower Volturno river basin, Campania Region, southern Italy). Pot experiments were performed by adding the NYT/PM mixture (1:1, w/w) to polluted soil at the rates of 0%, 25%, 50% or 75% (w/w). Wheat (Triticum aestivum) was used as the test plant. The addition of organo-zeolite NYT/PM mixture significantly reduced the DTPA (diethylene-triamine-pentaaceti c acid)-extractable Cd and Pb from 1.01 and 97.5 mg kg−1 in the polluted soil, to 0.14 and 11.6 mg kg−1, respectively, in the soil amended with 75% NYT/PM. The best plant response was observed in amended soil systems treated with 25% NYT/PM, whereas larger additions induced plant toxicities due to increased soil salinity.

Neapolitan yellow tuff for the recovery of soils polluted by potential toxic elements in illegal dumps of Campania Region

The Neapolitan yellow tuff (NYT) was utilized as a component of an organo-mineral sorbent/exchanger soil conditioner with pellet manure (NYT/PM) to limit the mobility of Cd and Pb in heavily polluted soils from illegal dumps in Low Volturno river basin (Campania Region, southern Italy). The NYT/PM mixture (1:1, w/w) was added to soil at the rates of 0%, 25%, 50% or 75% (w/w). The overall significant effect of the amendment with NYT/PM on soil properties was the substantial reduction of the availability of the toxic elements, with special reference to Pb, connected with an increase of cation exchange capacity and electrical conductivity and a moderate decrease of soil pH. The observed effects were primarily ascribed to the Pb-selectivity of phillipsite and chabazite present in the tuff matrix. On the whole, our findings suggest the suitability of NYT as natural exchanger material to be utilized in strategies for the remediation of polluted sites.

Modelling pedogenization of zeolitized tuff: effects of water and phenolic substances on weathering rates of the Campanian Ignimbrite (yellow facies)

Abstract An experimental pedology research project, based on a ‘‘process-system’’ pedogenetic model, was initiated to investigate the weathering of Phlegraean Yellow Tuff (PYT) - the yellow facies of the Campanian Ignimbrite with phillipsite > chabazite -as representative of the parent rock material as the soil-forming factor. PYT was weathered by water (W) and tannic acid solutions (TA) at concentrations ranging from 3×101 to 3×104 μmol l-1. The most concentrated TA solution (3×104 μmol l-1) showed the greatest extracting efficiency. Na and K were continually solubilized by W; Al, Ca and Mg contributed to the ionic composition of all the TA supernatants. A significant dissolution of the amorphous component and an associated decrease of the zeolite content, especially phillipsite, were noted. The features of PYT weathered outcomes fitted the ‘‘processsystem’’ model very well. PYT showed a pedogenic potential, in being prone to weathering, as well as in releasing elements of importance for plant settlement and development, such as K, Ca, Mg and Fe.

Zeolitized tuffs as pedogenic substrate for soil re-building. Early evolution of zeolite/organic matter proto-horizons

An investigation was undertaken aiming to evaluate the suitability of zeolitized tuffs as an anthropogeomorphic material for soil re-building in degraded and desertified areas. Four artificial soil proto-horizons were prepared utilizing fine limestone gravel or Neapolitan yellow tuff as inorganic components, and sewage sludge or pellet manure as organic parent materials. The proto-horizons evolution was followed by analyzing leachates periodically collected over 80 days. After 80 days, the body of proto-horizons was also analyzed. Our results showed that the release of C- and N- compounds in the leachates was strictly dependent on the nature of the parent organic material. The presence of Neapolitan yellow tuff in the proto-horizon bodies clearly favored an advantageous evolution and stabilization of parent organic matrices, in optimizing the carbon to nitrogen ratios by increasing the C/N values, and by protecting the organic matter tuff is a promising material in pedotechnique strategies for soil reconstruction and fight against desertification; on contrary, the organic matter appeared to be excessively demolished in the presence of limestone gravel.

Modeling pedogenization of zeolitized tuffs. II: medium-term weathering of phlegraean yellow tuff and red tuff with black scoriae by water and humic acids

An experimental pedology research program was started aiming at modeling the potential pedogenization of zeolitized tuffs. The present study deals with a medium-term weathering of Phlegraean Yellow Tuff (PYT, with phillipsite>chabazite) and Red Tuff with Black Scoriae (RTBS, with chabazite>phillipsite) under discontinuous treatment by water (W) and by humic acids (HA). Significant amounts of cations, increasing in the sequence Al<Fe<Mg<Ca, were extracted by both water and humic acids. The humic acids showed in all cases the highest extracting efficiency. All cations, especially calcium, were more easily removed from PYT than from RTBS. The only exception was iron which was preferentially removed from RTBS by HA. At the end of the experiment, smectite was not any more detected in the PYT residues. On the whole, the results indicate that PYT is more prone than RTBS to both humic acid and water weathering due to its different mineralogy.

Properties of zeolitized tuff/organic matter aggregates relevant for their use in pedotechnique. III: organic matter stability and exchange properties

Abstract A study was performed to evaluate the suitability of zeolitized tuffs to restore degraded soils. Ca-saturated Neapolitan yellow tuff or clinoptilolite-rich tuff from Turkey were mixed with organic matter either as humic matter (tannic acid, humic acids) or non-humic matter (polygalacturonic acid). Organic matter was strongly stabilized in clinoptilolite-rich tuff aggregates based on humic matter, whereas it was more easily oxidized in models with non-humic matter. Cation exchange capacity (CEC) was determined according to Ba/Mg-TEA method and by ammonium acetate procedure. The former method underestimated the CEC of the zeolitized tuffs, but was able to detect the contribution of organic matter to the CEC of aggregates. The latter method provided consistent CEC values for the zeolitized tuffs, but underestimated the exchange activity of the organic components of aggregates. CEC of aggregates including tannic acid was practically nil. Binding tannic acid to zeolite via Ca-bridges, results evidently in occlusion of zeolite pores.

Properties of zeolitized tuff/organic matter aggregates relevant for their use in pedotechnique I. Chemical and physical-chemical properties

Abstract A study aiming at evaluating the technical and economic suitability of zeolitized tuffs as mineral substrate for soil re-building in pedotechnique strategies was carried out. The chemical and physical-chemical properties of aggregates ped models, obtained by interaction between tannic acid, i.e., an organic matrix precursor of humic substances, and a zeolitized material, namely Neapolitan Yellow Tuff, using Ca ions as “bridge”, were investigated. Ped models were characterized according to chemical and physical standard methods for soil analysis, color analysis by visual interpretation and by spectro-radiometry, as well as by FT-IR spectrometry. The results suggest that the interaction between zeolite, Ca ions and tannic acid leads to the formation of stable aggregates with peculiar chemical and chemical-physical properties.

Changes of soil phosphorus availability in Italian alfisols as estimated by short‐term soil + phosphorus equilibration procedures using olsen, mehlich 3, and paper‐strip methods

Abstract The soil availability index, “F”, showed to be a suitable tool to assess the fraction of phosphorus (P) added to soil remaining available after a given time. However, the classical F determination methods are laborious and time‐consuming; so we devised more quick and simple procedure. This paper deals with the reliability of Olsen, Mehlich 3 (M3), and the innovative “iron‐impregnated paper‐strip” (Pi) methods to evaluate the F index by short‐term, double‐point soil+P equilibration procedures. Representative Italian Alfisol were examined: they were characterized by from low to high P Sorption Index (SI) values (4.6 to 35.4, mean 22.0) and from low to sufficient available Olsen‐P contents (2.0 to 33.0 ppm, mean 11.3). The samples were supplied with 0 or 50 mg P per kg soil (P0 or P50, respectively), and then incubated for 2 or 24 hours (short term soil+P incubation periods), or 90 days (long‐term period). At the balance, the available P was extracted by the compared methods and the respective F ind...

Zeolitized tuffs in pedotechniques to improve soil resilience against the impact of treatment by municipal sewage: balance of nutrient and noxious cations

Abstract Two zeolitized tuffs (ZTs), viz. a Neapolitan yellow tuff (NYT) and a clinoptilolitebearing tuff (ZCL), were tested as pedotechnical materials to improve soil resilience against the impact of treatment by a ‘dirty’ municipal sewage system (DSW). Soils (surface horizon) were a sandy, alkaline Entisol (Typic Xeropsamment), and a sandy-loam, sub-acidic Alfisol (Ultic Palexeralf). Results showed that the presence of ZTs resulted in several favourable effects. Electrical conductivity (EC) decreased and pH was buffered. Ammonium was selectively taken up from the DSW, making the zeolitized tuffs almost saturated by NH4+, by exchanging both beneficial cations, such as K+ and Ca2+, thus improving their potential availability to plants, and undesirable cations such as Na+, thereby hindering the exchangeable sodium percentage (ESP) increase and concurrent soil salinization-alkalinization. At the same time, NH4+ was stored as a potentially slow-release nitrogen fertilizer. The mobility of Pb, Cu and Zn dropped off to a large extent. NYT produced the best effects, and the Entisol gained the greatest benefit from treatments.

Properties of zeolitized tuff/organic matter aggregates relevant for their use in pedotechnique. IIb: Structural characterization with emphasis on surface and porosity properties

Abstract A study is in progress aiming at characterizing the chemical, chemical-physical and structural properties of organo-zeolite aggregates relevant for their use in pedological technologies for soil restoration. This paper deals with the surface and porosity properties of organo-zeolite aggregates formed by Neapolitan Yellow Tuff (N), tannic acid (T), and Ca 2+ bridging ion, with different T/N ratios. T acted as a molecular plug. dramatically decreasing both the surface area and the micropore volume.