Performance of Earth Plasters with Graphene-Based Additive.

A central debate is the improvement in the mechanical and water resistance of sustainable earthen architecture without additives or stabilizers. This innovative work aims to test the effects of a graphene-based additive, optimized for the improvement in concrete properties, on the strength and water resistance of raw-earth plasters without any stabilizer other than sand. Given the heterogeneous nature of raw earth, three different soils were tested by adding three increasing graphene-based additive contents (0.01, 0.05 and 0.1 wt% of the earth-sand proportion). The link between soil intrinsic properties, i.e., geotechnical and mineralogical properties, and their interaction with the additive were investigated through geotechnical characterization, as well as mineralogical characterization, by XRD and ATR-FTIR analyses. The experimental tests carried out focused on the adhesion properties of the twelve different plasters on standard hollow bricks and on their interaction with water through capillary rise tests and erosion resistance tests. Conclusion from the experimental tests suggests that the graphene-based additive in earth plasters, by increasing the cohesion of the mixture, improves their adhesion performance.

A Commercial Clay-Based Material as a Carrier for Targeted Lysozyme Delivery in Animal Feed.

The controlled supply of bioactive molecules is a subject of debate in animal nutrition. The release of bioactive molecules in the target organ, in this case the intestine, results in improved feed, as well as having a lower environmental impact. However, the degradation of bioactive molecules' in transit in the gastrointestinal passage is still an unresolved issue. This paper discusses the feasibility of a simple and cost-effective procedure to bypass the degradation problem. A solid/liquid adsorption procedure was applied, and the operating parameters (pH, reaction time, and LY initial concentration) were studied. Lysozyme is used in this work as a representative bioactive molecule, while Adsorbo®, a commercial mixture of clay minerals and zeolites which meets current feed regulations, is used as the carrier. A maximum LY loading of 32 mgLY/gAD (LY(32)-AD) was obtained, with fixing pH in the range 7.5-8, initial LY content at 37.5 mgLY/gAD, and reaction time at 30 min. A full characterisation of the hybrid organoclay highlighted that LY molecules were homogeneously spread on the carrier's surface, where the LY-carrier interaction was mainly due to charge interaction. Preliminary release tests performed on the LY(32)-AD synthesised sample showed a higher releasing capacity, raising the pH from 3 to 7. In addition, a preliminary Trolox equivalent antioxidant capacity (TEAC) assay showed an antioxidant capacity for the LY of 1.47 ± 0.18 µmol TroloxEq/g with an inhibition percentage of 33.20 ± 3.94%.

Study of Innovative GO/PBI Composites as Possible Proton Conducting Membranes for Electrochemical Devices.

The appeal of combining polybenzimidazole (PBI) and graphene oxide (GO) for the manufacturing of membranes is increasingly growing, due to their versatility. Nevertheless, GO has always been used only as a filler in the PBI matrix. In such context, this work proposes the design of a simple, safe, and reproducible procedure to prepare self-assembling GO/PBI composite membranes characterized by GO-to-PBI (X:Y) mass ratios of 1:3, 1:2, 1:1, 2:1, and 3:1. SEM and XRD suggested a homogenous reciprocal dispersion of GO and PBI, which established an alternated stacked structure by mutual π-π interactions among the benzimidazole rings of PBI and the aromatic domains of GO. TGA indicated a remarkable thermal stability of the composites. From mechanical tests, improved tensile strengths but worsened maximum strains were observed with respect to pure PBI. The preliminary evaluation of the suitability of the GO/PBI X:Y composites as proton exchange membranes was executed via IEC determination and EIS. GO/PBI 2:1 (IEC: 0.42 meq g-1; proton conductivity at 100 °C: 0.0464 S cm-1) and GO/PBI 3:1 (IEC: 0.80 meq g-1; proton conductivity at 100 °C: 0.0451 S cm-1) provided equivalent or superior performances with respect to similar PBI-based state-of-the-art materials.

Reduced Graphene Oxide/Waste-Derived TiO2 Composite Membranes: Preliminary Study of a New Material for Hybrid Wastewater Treatment.

This work reports the preliminary results of the development of composite self-assembling membranes obtained by the combination of reduced graphene oxide (rGO) with commercial Degussa P25 titanium dioxide (TiO2). The purpose is to demonstrate the possibility of combining, in the same self-standing material, the capability to treat wastewater containing both inorganic and organic pollutants by exploiting the established ability of rGO to capture metal ions together with that of TiO2 to degrade organic substances. Moreover, this study also investigates the potential photocatalytic properties of tionite (TIO), to demonstrate the feasibility of replacing commercial TiO2 with such waste-derived TiO2-containing material, fulfilling a circular economy approach. Thus, rGO-TiO2 and rGO-TIO composite membranes, 1:1 by weight, were prepared and characterized by SEM-EDX, XRD, thermogravimetry, as well as by Raman and UV-Vis spectroscopies to verify the effective and homogeneous integration of the two components. Then, they were tested towards 3-mg L-1 aqueous synthetic solutions of Fe3+ and Cu2+ ions to evaluate their metal adsorption ability, with values of the order of 0.1-0.2 mmol gmembrane-1, comparable or even slightly higher than those of pristine rGO. Finally, the ability of the composites to degrade a common organic pesticide, i.e., Imidacloprid®, was assessed in preliminary photocatalysis experiments, in which maximum degradation efficiencies of 25% (after 3 h) for rGO-TiO2 and of 21% (after 1 h) for rGO-TIO were found. The result of tionite-containing membranes is particularly promising and worthy of further investigation, given that the anatase content of tionite is roughly 1/6 of the one in commercial TiO2.

Environmental and health-related external costs of meat consumption in Italy: estimations and recommendations through life cycle assessment.

The literature on the external costs of food consumption is limited. This study aims at advancing in this field by translating the environmental and health-related impacts generated by the life-cycle of meat into external costs via monetization. The main types of meat consumed in Italy are used as a case study. The potential external costs are estimated via attributional life cycle assessment (LCA), using: i) the ReCiPe method for the environmental impact assessment (fourteen impact categories), ii) the population attributional fractions for the health damage from meat ingestion, and iii) the CE Delft environmental prices for monetization. Results show that processed pork and beef generate the highest costs on society, with an external cost of approximately 2€ per 100 g. Fresh pork and poultry follow, with a cost of 1€ and 0.5€ per 100 g, respectively. For comparison, the potential external costs of legumes (i.e., a plant-based alternative to meat) are estimated to be from eight to twenty times lower than meat (around 0.05€ per 100 g of legumes). In 2018, meat consumed in Italy potentially generated a cost on society of 36.6 bn€. The burden arises almost equally from impacts generated before meat ingestion (mainly associated with the emissions arisen from farming), and after the ingestion (due to diseases potentially associated with meat consumption). A sensitivity analysis on the main parameters revealed a large uncertainty on the final yearly cost, ranging from 19 to 93 bn€. Although more research is needed to improve the accuracy and the validity of the models used in the study (e.g., human health impact assessment, monetization) and to include potential external costs currently unaccounted for (e.g., water use, animal welfare, occupational health), results show unequivocal significant costs associated with meat consumption. We thus advocate for policies aimed at reducing these costs and allocating them properly.

Analysis of the Adsorption-Release Isotherms of Pentaethylenehexamine-Modified Sorbents for Rare Earth Elements (Y, Nd, La).

Waste from electrical and electronic equipment (WEEE) is constantly increasing in quantity and becoming more and more heterogeneous as technology is rapidly advancing. The negative impacts it has on human and environment safety, and its richness in valuable rare earth elements (REEs), are accelerating the necessity of innovative methods for recycling and recovery processes. The aim of this work is to comprehend the adsorption and release mechanisms of two different solid sorbents, activated carbon (AC) and its pentaethylenehexamine (PEHA)-modified derivative (MAC), which were deemed adequate for the treatment of REEs deriving from WEEE. Experimental data from adsorption and release tests, performed on synthetic mono-ionic solutions of yttrium, neodymium, and lanthanum, were modelled via linear regression to understand the better prediction between the Langmuir and the Freundlich isotherms for each REE-sorbent couple. The parameters extrapolated from the mathematical modelling were useful to gain an a priori knowledge of the REEs-sorbents interactions. Intraparticle diffusion was the main adsorption mechanism for AC. PEHA contributed to adsorption by means of coordination on amino groups. Release was based on protons fostering both a cation exchange mechanism and protonation. The investigated materials confirmed their potential suitability to be employed in real processes on WEEE at the industrial level.

Mechanical and Microstructural Characterization of Rammed Earth Stabilized with Five Biopolymers.

This study aims to check the compatibility of a selection of waste and recycled biopolymers for rammed earth applications in order to replace the more common cement-based stabilization. Five formulations of stabilized rammed earth were prepared with different biopolymers: lignin sulfonate, tannin, sheep wool fibers, citrus pomace and grape-seed flour. The microstructure of the different formulations was characterized by investigating the interactions between earth and stabilizers through mercury intrusion porosimetry (MIP), nitrogen soprtion isotherm, powder X-ray diffraction (XRD) and scanning electron microscopy (SEM). The unconfined compressive strength (UCS) was also evaluated for all stabilized specimens. Three out of five biopolymers were considered suitable as rammed earth stabilizers. The use of wool increased the UCS by 6%, probably thanks to the combined effect of the length of the fibers and the roughness of their surfaces, which gives a contribution in binding clay particles higher than citrus and grape-seed flour. Lignin sulfonate and tannin increased the UCS by 38% and 13%, respectively, suggesting the additives' ability to fill pores, coat soil grains and form aggregates; this capability is confirmed by the reduction in the specific surface area and the pore volume in the nano- and micropore zones.

Investigation of Sulfonated Graphene Oxide as the Base Material for Novel Proton Exchange Membranes.

This work deals with the development of graphene oxide (GO)-based self-assembling membranes as possible innovative proton conductors to be used in polymer electrolyte membrane fuel cells (PEMFCs). Nowadays, the most adopted electrolyte is Chemours' Nafion; however, it reveals significant deficiencies such as strong dehydration at high temperature and low humidity, which drastically reduces its proton conductivity. The presence of oxygenated moieties in the GO framework makes it suitable for functionalization, which is required to enhance the promising, but insufficient, proton-carrying features of GO. In this study, sulfonic acid groups (-SO3H) that should favor proton transport were introduced in the membrane structure via a reaction between GO and concentrated sulfuric acid. Six acid-to-GO molar ratios were adopted in the synthesis procedure, giving rise to final products with different sulfonation degrees. All the prepared samples were characterized by means of TGA, ATR-FTIR and Raman spectroscopy, temperature-dependent XRD, SEM and EDX, which pointed out morphological and microstructural changes resulting from the functionalization stage, confirming its effectiveness. Regarding functional features, electrochemical impedance spectroscopy (EIS) as well as measurements of ion exchange capacity (IEC) were carried out to describe the behavior of the various samples, with pristine GO and commercial Nafion® 212 used as reference. EIS tests were performed at five different temperatures (20, 40, 60, 80 and 100 °C) under high (95%) and medium (42%) relative humidity conditions. Compared to both GO and Nafion® 212, the sulfonated specimens demonstrate an increase in the number of ion-carrying groups, as proved by both IEC and EIS tests, which reveal the enhanced proton conductivity of these novel membranes. Specifically, an acid-to-GO molar ratio of 10 produces a six-fold improvement of IEC (4.23 meq g-1) with respect to pure GO (0.76 meq g-1), while a maximum eight-fold improvement (5.72 meq g-1) is achieved in SGO-15.

Data on roof renovation and photovoltaic energy production including energy storage in existing residential buildings.

This data article refers to the paper "Optimizing photovoltaic electric generation and roof insulation in existing residential buildings" [1]. The reported data deal with roof retrofit in different types of existing residential buildings (single-family, multi-family and apartment complex) located in Milan (Northern Italy). The study focus on the optimization of envelope insulation and photovoltaic (PV) energy production associated with different building geometries, initial insulation level, roof constructions, and materials. The data linked within this article relate to the modelled building energy consumption, renewable production, potential energy savings, and costs. Data refer to two main scenarios: refurbishment (roof in need of replacement and insulation) and re-roofing (energy intervention for roof improvement). Data allow to visualize energy consumption before and after the optimization, selected insulation level and material, costs and PV renewable production (with and without energy storage). The reduction of energy consumption can be visualized for each building type and scenario. Further data is available on CO2 emissions, envelope, materials, and systems.

Capture and Release Mechanism of Ni and La Ions via Solid/Liquid Process: Use of Polymer-Modified Clay and Activated Carbons.

This study is a starting point for the development of an efficient method for rare earths (REs) and transition metals (TMs) recovery from waste electrical and electronic equipment (WEEE) via a hydrometallurgical process. The capture and release capability of mineral clays (STx) and activated carbons (AC), pristine and modified (STx-L6 and AC-L6) with a linear penta-ethylene-hexamine (L6), towards solutions representative of the process, are assessed in the lab-scale. The solids were contacted with synthetic mono- and bi-ionic solutions containing Ni(II) and La(III) in a liquid/solid adsorption process. Contacting experiments were carried out at room temperature for 90 min by fixing a La concentration at 19 mM and varying the Ni one in the range of 19-100 mM. The four solids were able to capture Ni(II) and La(III), both in single- and bi-ionic solutions; however, the presence of the polyamine always results in a large improvement in the capture capability of the pristine sorbents. For all the four solids, capture behaviour is ascribable to an adsorption or ion-sorbent interaction process, because no formation of aquo- and hydroxy-Ni or La can be formed. The polyamine, able to capture Ni ions via coordination, allowed to differentiate ion capture behaviour, thus bypassing the direct competition between Ni and La ions for the capture sites found in the pristine solids. Release values in the 30-100% range were found upon one-step treatment with concentrated HNO3 solution. However, also, in this case, different metals recovery was found depending on both the sorbent and the ions, suggesting a possible selective recovery.

Can TEMPO-Oxidized Cellulose Nanofibers Be Used as Additives in Bio-Based Building Materials? A Preliminary Study on Earth Plasters.

Interest towards cellulose nanofibers obtained from virgin and waste sources has seen a significant growth, mainly thanks to the increasing sensitivity towards the concept of circular economy and the high levels of paper recycling achieved in recent years. Inspired by the guidelines of the green building industry, this study proposes the production and characterization of TEMPO-oxidized and homogenized cellulose nanofibers (TOHO CNF) from different sources and their use as additives for earth plasters on two different raw earth samples, characterized by geotechnical laboratory tests and mineralogical analysis: a high-plasticity clay (T2) and a medium-compressibility silt (ABS). Original sources, including those derived from waste (recycled cardboard and paper mill sludge), were characterized by determining chemical content (cellulose versus ashes and lignin) and fiber morphology. TOHO CNF derived from the different sources were compared in terms of nanofibers medium diameter, crystallinity degree, thermal decomposition and oxidation degree, that is the content of carboxylic groups per gram of sample. Then, a preliminary analysis of the influence of CNF on earth plasters is examined. Adhesion and capillary absorption tests highlighted the effect of such nanofibers on blends in function of two factors, namely the cellulose original source and the oxidation degree of the fibers. In particular, for both earth samples, T2 and ABS, a significant increase in adhesion strength was observed in the presence of some TOHO CNF additives. As far as capillary sorption tests, while an undesired increase in water adsorption was detected for T2 compared to the control, in the case of ABS, a significant reduction in water content was measured by adding TOHO CNF derived from recycled sources. These results pave the way for further in-depth investigation on the role of TOHO CNF as additives for earth plasters.

Comparative Life Cycle Assessment of Cellulose Nanofibres Production Routes from Virgin and Recycled Raw Materials.

Nanocellulose-based materials are attracting an increasing interest for the positive role they could play in sustainable development; being originated from renewable resources. Moreover, cellulose has a high potential of recycling from both post-consumer waste and industrial waste. Both factors, i.e., recyclability and renewable resources; results are also extremely favourable in the perspective of circular economy. Despite all these positive aspects, an industrial production has yet to start. At the lab scale, many preparation methods of cellulose nanofibres (CNF) are available; here, the three most common are analysed: (1) enzymatic pre-treatment followed by homogenisation (ENZHO), (2) oxidative pre-treatment combined with homogenisation (TOHO) or (3) oxidative pre-treatment followed by sonication (TOSO). All three processes have been experimentally carried out starting from both virgin and recycled cellulose from industrial waste sludge. The environmental sustainability of these three routes is estimated by the Life Cycle Assessment (LCA) using experimental lab scale data. In this scenario, the comparative LCA has pointed out a superior performance of the ENZHO process, followed by TOHO and, lastly, by TOSO. The influence of energy consumption on the final results has been further investigated by a sensitivity analysis, showing that the TOHO and TOSO routes could reach similar performances by scaling-up the process from the laboratory. The different typology of CNF obtained by conducting the ENZHO process with respect to the TEMPO-mediated oxidation approach is also outlined as an additional element to be considered for the final selection of a suitable process.

Experimental Characterization of Polymer Surfaces Subject to Corona Discharges in Controlled Atmospheres.

Polymeric dielectrics are employed extensively in the power transmission industry, thanks to their excellent properties; however, under normal operating conditions these materials tend to degrade and fail. In this study, samples of low-density polyethylene, polypropylene, polymethyl methacrylate, and polytetrafluorethylene were subjected to corona discharges under nitrogen and air atmospheres. The discharges introduced structural modifications over the polymer surface. From a chemical perspective, the alterations are analogous among the non-fluorinated polymers (i.e., polyethylene (PE), polypropylene (PP), and polymethyl methacrylate (PMMA)). A simulation of the corona discharge allowed the identification of highly reactive species in the proximity of the surface. The results are consistent with the degradation of insulating polymers in high-voltage applications due to internal partial discharges that ultimately lead to the breakdown of the material.

Polyamine-Based Organo-Clays for Polluted Water Treatment: Effect of Polyamine Structure and Content.

Hybrid materials based on clays and polyamines are supposed to be efficient heavy metals sorbents due to the well-known adsorption behaviour of the clay matrix and to the coordination properties of un-protonated amino groups. For this purpose, a montmorillonite clay was modified with three different aliphatic polyamines: L6 and L10 have a linear structure with six and ten amino groups, respectively, while B14 is a branched polyamine with fourteen amino groups. Initial amine concentration was the main parameter investigated and data were fitted with Langmuir and Freundlich models. Interaction mechanisms between clay and amines were deeply investigated by different experimental techniques such as X-ray powder diffraction (XRD), thermal analysis measurements (DTG), Fourier Transform Infrared Spectroscopy (FT-IR) and diffuse reflectance (NIR) spectroscopy. Experimental results showed that the amount of amines efficiently immobilized in the solid phase can be increased by increasing the initial concentration of polyamines in the clay modification process. These data were best fitted by Freundlich model, indicating a presence of surface sites of different nature. In the resulting hybrid materials, neither the accessibility of the NH/NH2 groups of the amines, nor the accessibility of the structural OH of the clay was hindered. Several preliminary tests in La ions' uptake and release from aqueous solution were also carried out. In the conditions used for this study, total metal ion removal was achieved at sufficiently low linear amine loadings (i.e., 0.45 mmol/gclay for the small L6 amine), suggesting that these hybrid materials are promising for the proposed application in environmental remediation.

From beans to bar: A life cycle assessment towards sustainable chocolate supply chain.

The environmental sustainability has emerged as a crucial aspect in the agri-food sector, nevertheless environmental assessments and certifications of cocoa and chocolate are still missing. Given this gap and the increasing global demand for cocoa derivatives, this study aims to evaluate the environmental impacts of an Italian dark chocolate through a holistic cradle-to-grave Life Cycle Assessment (LCA). The impact categories assessed are acidification potential (AC), eutrophication potential (EU), global warming potential (GW), photochemical ozone creation potential (POC), ozone layer depletion potential (OD), abiotic depletion (AD) and cumulative energy demand (CED). The obtained results highlight the relevant contributions of upstream phase (63% for the ODP, 92% for EU and 99% for the AD) and core processes (39% for the GW and 49% for the CED) on the overall impacts. Specifically, cocoa provisioning and energy supply at the manufacturing plant emerged as environmental hotspots and have been deeper investigated through a sensitivity analysis. Obtained outcomes show the significant variability of the environmental impacts due to the agricultural phase (i.e., depending on agroecosystems and practices) and environmental benefits guaranteed by an efficient trigeneration system implemented in the manufacturing plant. The quantification of the environmental impacts of chocolate through LCA, the identification of the main hotspots along the supply chain and the sensitivity analysis performed in this study could effectively support chocolate companies in their pathway towards environmentally sustainable productions.

Recovery of valuable metals from electronic scraps by clays and organo-clays: Study on bi-ionic model solutions.

The demand of valuable metals, as precious metals and rare earths, is constantly increasing in the global market, as many and different technological applications exploit these materials because of their unique properties. Since natural resources are located just in focused areas, an interesting possibility could be the recovery of metals from Waste Electrical and Electronic Equipment (WEEE). The aim of this work is to evaluate the recovery potentialities of clays and organo-clay based systems towards the metals contained in the solutions of electronic scraps dissolved in strong acid, by preliminary tests on bi-ionic model solutions. Lanthanum has been chosen as representative of the rare earths while copper has been considered since it is by far the most used metal in electric and electronic equipment. The considered sorbents are a montmorillonitic clay and two polyamine based organo-clays. Uptake and release processes have been carried out in order to assess the performances of these solids and to evaluate the uptake and release mechanisms. The results showed that the cationic exchange is the prevailing mechanism in the case of pristine clay, while both coordinating effect due to amino groups and cationic exchange occur in the case of modified clays, respectively accounting for copper and lanthanum uptake. Furthermore the pH was found having a great influence in both the adsorption and desorption phenomena.

Use of natural clays as sorbent materials for rare earth ions: Materials characterization and set up of the operative parameters.

Two mineral clays of the montmorillonite group were tested as sorbents for the removal of Rare Earths (REs) from liquid solutions. Lanthanum and neodymium model solutions were used to perform uptake tests in order to: (a) verify the clays sorption capability, (b) investigate the sorption mechanisms and (c) optimize the experimental parameters, such as contact time and pH. The desorption was also studied, in order to evaluate the feasibility of REs recovery from waters. The adsorption-desorption procedure with the optimized parameters was also tested on a leaching solution obtained by dissolution of a dismantled NdFeB magnet of a hard-disk. The clays were fully characterized after REs adsorption and desorption by means of X-ray powder diffraction (XRPD) and X-ray photoelectron spectroscopy (XPS); the liquid phase was characterized via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) analyses. The experimental results show that both clays are able to capture and release La and Nd ions, with an ion exchange mechanism. The best total efficiency (capture ≈ 50%, release ≈ 70%) is obtained when the uptake and release processes are performed at pH=5 and pH=1 respectively; in real leached scrap solutions, the uptake is around 40% but release efficiency is strongly decreased passing from a mono-ion system to a real system (from 80% to 5%). Furthermore, a strong matrix effect is found, with the matrix largely affecting both the uptake and the release of neodymium.

Life cycle assessment of hemp cultivation and use of hemp-based thermal insulator materials in buildings.

The aim of this research is to assess the sustainability of a natural fiber, such as hemp (Cannabis sativa), and its use as thermal insulator for building applications. The sustainability of hemp was quantified by life cycle assessment (LCA) and particular attention was given to the amount of CO2eq of the whole process, and the indicator greenhouse gas protocol (GGP) was selected to quantify CO2eq emissions. In this study also CO2 uptake of hemp was considered. Two different allocation procedures (i.e., mass and economic) were adopted. Other indicators, such as Cumulative Energy Demand (CED) and EcoIndicator99 H were calculated. The production of 1 ha yielded 15 ton of hemp, whose global warming potential (GWP100) was equal to about -26.01 ton CO2eq: the amount allocated to the technical fiber (20% of the total amount of hemp biomass) was -5.52 ton CO2eq when mass allocation was used, and -5.54 ton CO2eq when economic allocation was applied. The sustainability for building applications was quantified by considering an insulation panel made by hemp fiber (85%) and polyester fiber (15%) in 1 m(2) of wall having a thermal transmittance (U) equal to 0.2 W/m(2)_K. The environmental performances of the hemp-based panel were compared to those of a rockwool-based one.

Hybrid organo-inorganic clay with nonionic interlayers. mid- and near-IR spectroscopic studies.

The intercalation of organic polymers molecules (i.e., PEGs and BRIJ) into a standard Ca-montmorillonite has been studied by XRD, TG, and IR spectroscopy. The polymer intercalation is confirmed by the increasing of the d(001) in XRD spectra as well as by the complex multisteps thermal decomposition behavior of the organo-clay materials. Mid-IR and diffuse reflectance near-IR spectra of the intercalated materials show the polymer diagnostic bands (CH stretching and deformation mode), shifted or changed in shape by the interaction with the clay matrix. Both PEG 1500 and PEG 4000 based materials are likely intercalated in an extended configuration, similar to the amorphous polymer form. BRIJ intercalated polymer spectra suggest the disordered conformation of the alkilic chain in a prevailing "gauche", poorly packed, conformation. Host montmorillonite IR bands, mainly OH and water stretching and deformation fundamentals, combination, and overtone bands, are reduced in intensity by polymer intercalation, pointing out an interaction, likely through H-bonding and/or a possible substitution of cations hydration water molecules.

Use of admixtures in organic-contaminated cement-clay pastes.

In this work microstructure, porosity and hydration degree of cement-based solidified/stabilized wasteforms were studied before assessing their leaching behaviour. 2-Chloroaniline was chosen as a model liquid organic pollutant and included into cement pastes, which were also modified with different admixtures for concrete: a superplasticizer based on acrylic-modified polymer, a synthetic rubber latex and a waterproofing agent. An organoclay, modified with an ammonium quaternary salt (benzyl-dimethyl-tallowammonium, BDMTA), was added to the pastes as pre-sorbent agent of the organic matter. All the samples were dried up to constant weight in order to stop the hydration process at different times during the first 28 days of curing, typically, after 1 day (1d), 7 days (7d) and 28 days. Then, the microstructure of the hardened cement-clay pastes was investigated by powder X-ray diffraction (XRD). The hydration degree and porosity were studied by thermal analysis (TG/DTA) and mercury intrusion porosimetry (MIP), respectively. For samples cured for 28 days a short-term leach test set by Italian regulation for industrial waste recycling (D.M. 5 February 1998) was performed. The best results showed a 5% release of the total initial amount of organic pollutant.