Salt Mobilization Research Articles

Characterization of the Oxidation Degradation Products in Tigecycline by Column-Switching and Online Demineralization Technique for Dual Gradient Liquid Chromatography Combined With Q Orbitrap Mass Spectrometry

The oxidation degradation products in tigecycline were separated and identified by column-switching and online demineralization technique for dual gradient high-performance liquid chromatography (DGLC) combined with Q Orbitrap mass spectrometry for the further improvement of official monographs in pharmacopoeias. Each peak eluted from the non-volatile system was trapped by a switching valve and sent to an LC–MS system using a volatile mobile phase. Thermo Ultimate 3000 DGLC combined with Q Orbitrap MS equipped with electrospray ionization was scanning in positive and negative ion modes at the same time. The one-dimensional analytical column was Welch Ultimate XB-C18 (250 mm × 4.6 mm, 5 μm) with non-volatile salt mobile phase at the flow rate of 1.5 mL min−1 (left pump), and the two-dimensional analytical column was Thermo Acclaim™ 120 C18 (250 mm × 4.6 mm, 5 μm) with a volatile salt mobile phase at the flow rate of 0.3 mL min−1 (right pump). The column temperature was at 30 °C. The detection wavelength was 248 nm. The column-switching and online demineralization technique made it possible to characterize tigecycline in the condition of official standard. The complete fragmentation patterns of impurities were studied and used to obtain information about the structures of these impurities. Mass Frontier software version 7.0 from Thermo Finnigan was used to simulate and study the fragmentation behavior of the described compounds. The structures of six oxidation degradation products in tigecycline were deduced based on the high-resolution MSn data, in which five impurities were novel impurities. The forming mechanisms of oxidation degradation products in tigecycline were also studied. The method solved the problem of incompatibility between non-volatile salt mobile phase and mass spectrometry. It is worthy of widespread use and application, with the advantages of stability and repeatability.

Using potential field data to map salt distribution in the Western Officer Basin, Western Australia.

SUMMARY The Neoproterozoic western Officer Basin has a total fill of up to 8 km and a depositional history with similarities to other Australian basins, particularly the Amadeus Basin. Exploration has been limited due to the size and remoteness of the basin; therefore potential field data can be a useful and cost-effective tool to assess petroleum prospectivity. Salt distribution and mobilisation in the Officer Basin has been significantly underestimated due to a lack of quality seismic data. This study uses satellite, digital terrain, magnetic, gravity and seismic data to show the existence of mobilised salt much further west than previously suggested, with significant implications for future exploration in the region.

Groundwater salinization survey of the Upper Cretaceous-Miocene Complexe terminal aquifer in the Sabaa Biar area of southwestern Tunisia

An integrated hydrogeological study involving the Schlumberger depth sounding method, geological data and wells data was conducted at the Sabaa Biar area of southern Tunisia to elucidate the problem of increasing groundwater salinity within The “Complexe Terminal”. The “Complexe Terminal” aquifer near Sabaa Biar region is a bi-layered aquifer comprised of fractured limestones of the Cretaceous (Campanian–Maastrichtian) Berda Formation and sandstone of the Miocene Beglia Formation. The aquifer is affected by a main NW–trending fault, which is a chemical barrier that divides the study area into eastern and western blocks delivering freshwater and saline water, respectively. The salinization of groundwater within the limestone (Campanian–Maastrichtian Berda Formation) is linked mainly to the dissolution of outcropping Coniacian–Santonian gypsum along the core of the Jebel Sidi Bouhlel anticline to the east of the study area. Meteoric water dissolves salt from outcropping gypsum, flows through the fractures networks, and recharges the fractured limestone of the upper Berda Formation. The mobilization of salts stored in the salt-rich Quaternary sediment on hillslopes and inchannels contributes also to the salinization of groundwater within the sandstone (Miocene Beglia Formation) by lateral infiltration subsequent to water drainage during the wet season. The over exploitation of water from the Miocene sandstone causes an influx of saline-rich water from the underlying limestone of the Berda Formation into the sandstone of the Beglia Formation. Other sources of salinization of groundwater (such as ascension of hypersaline water from deep aquifer along faults, and the return flow of irrigation waters in the Djerid region) have been documented in this region, but are not discussed in this paper.

In situ DRIFT, Raman, and XRF implementation in a multianalytical methodology to diagnose the impact suffered by built heritage in urban atmospheres.

This work addresses the evaluation of an innovative mutianalytical method to assess the conservation state of a fifteenth century palace house. With the goal of reducing the handicaps of field analysis, the in situ spectroscopic assessment, often based on the use of X-ray fluorescence and Raman spectrometers, was complemented by the use of diffuse reflectance infrared Fourier transform spectroscopy. In this manner, its usefulness as a diagnostic tool to discover the origin and mechanisms of the damage caused by atmospheric and infiltration water attacks were thoroughly examined. Moreover, the study was extended in the laboratory to increase the information obtained by nondestructive techniques. The results revealed a severe material loss caused by soluble salts. Thus, a noninvasive sampling method using cellulose patches was tested to study the amount and mobility of salts by means of ion chromatography. Finally, to establish the chemical degradation processes that are occurring in the palace, a chemometric analysis of the quantitative data as well as the construction of thermodynamic models was done to advise on the required restorative actions. Graphical Abstract The different phases of the multianalytical method to assess the conservation state of built heritage.

Salinity hazard and risk mapping of point source salinisation using proximally sensed electromagnetic instruments

In many irrigated areas in the Murray–Darling Basin, New South Wales, Australia, point-source salinisation has occurred in isolated cases. In the lower Macquarie valley, near Trangie and Warren, the cause appears to be the mobilisation of salts from perched water tables and as a function of excessive deep drainage from water storages and conveyance channels. In order to understand these hazard factors and understand the risk of further salinisation, the spatial distribution of the various factors need to be mapped. Two methods have previously been employed and include the use of GIS hazard layer (e.g. geology, topography) analysis or airborne electromagnetic (EM) mapping. The former uses qualitative data which is often unreliable, whilst the latter has large start-up costs. In this study, various sources of proximally sensed data (i.e., EM38, EM34) are first used to develop stepwise-multiple linear regression (MLR) models to map the spatial distribution of vadose-zone (0–7m) clay and salt stores. Using a salt-water balance model (SaLF), deep drainage (mm/year) is estimated. The model has an exponential form and uses ancillary data as predictors. The predicted clay, salt store and deep drainage hazard maps are further employed to develop a map of overall salinity risk using Boolean logic and indicator kriging. Results suggest that the areas exhibiting the largest conditional probability of salinity risk correspond to permeable soil types associated with the Trangie Cowal, Contemporary Macquarie and Backplain of Old Alluvium Pedoderm. It was also noted that the predicted salinity risk was consistent with where salinisation had occurred in both Trangie and Warren districts. The methodology indicated where a more strategic approach needs to be implemented when considering options to improve irrigation efficiencies and water delivery southeast of Warren and Trangie. It also showed where more detailed investigations could be undertaken to better understand the stratigraphic nature of the landscape and the mobilisation of the salts therein.

Major faults, salt structures and paleo-ridge at tectonic nodes in Northern Tunisia: contribution of tectonics and gravity analysis

Structural analysis, fault kinematics, detailed geological mapping and gravity analysis provide a new approach regarding to the tectonic-model of the Bazina–Aouana structure (North–Eastern Tunisia). They show that the Bazina Triassic outcrops, such as several other structures, are related to the NE and E trending major faults junction, controlling its halokinesis, and pouring out to the NW of tectonic nodes in the collapsed compartment. During the Eocene and Tortonian compressive phases, the Triassic materials previously forming a intumescence in the NE and E major faults intersection have acted as a barrier on which collided the Aouana structure. Therefore, this structure is blocked between overthrust nappes and the Bazina paleo-ridge forming an imbricated zone overlapping the Triassic materials. This paper aims to present a new evolutionary geodynamic model for the Bazina–Aouana structure related to the tectonic node easing the Triassic salt mobilization, the paleo-ridge formation and the development of a collapsed zone. By comparing with previous works, this model is likely applicable to the important Triassic outcrops of Northern Tunisia.

Along‐strike evolution of folding, stretching and breaching of supra‐salt strata in the Plataforma Burgalesa extensional forced fold system (northern Spain)

AbstractThe Plataforma Burgalesa is a partly exposed extensional forced fold system with an intermediate salt layer, which has developed along the southern portion of the Basque‐Cantabrian Basin from Malm to Early Cretaceous as part of the Bay of Biscay‐Pyrenean rift system. Relationships between syn‐ and pre‐rift strata of the supra‐salt cover sequence and distribution of intra‐cover second‐order faults are observed both along seismic sections and at the surface. These relationships indicate an along‐strike variability of the extensional structural style. After a short period of salt mobilization and forced folding, high slip rates in the central portion of the major basement faults have rapidly promoted brittle behaviour of the salt layer, preventing further salt mobilization and facilitating the propagation of the fault across the salt layer. In contrast, at the tip regions of basement faults, slower slip rates have facilitated ductile salt behaviour, ensuring its further evaporite evacuation, preventing fault propagation across the salt layer and, in essence, allowing for a long‐living forced folding process. Our results indicate the important effect of along‐strike variation in displacement and displacement rates in controlling evaporite behaviour in extensional basins. Amount of displacement and displacement rates are key factors controlling the propagation of basement faults across evaporite layers. In addition, growth strata patterns are recognized as a powerful tool for constraining the up‐dip propagation history of basement faults in extensional fault‐related fold systems with intermediate décollement levels.

Late Palaeozoic to Early Cenozoic geological evolution of the northwestern German North Sea (Entenschnabel): New results and insights

AbstractThe results of a detailed seismic mapping campaign of 13 horizons in the northwestern German North Sea, covering Late Permian to Palaeogene sedimentary successions, are presented. Based on the interpretation of four 3D and two 2D seismic surveys, thickness and depth maps of prominent stratigraphic units were constructed. These maps provide an overview of key structural elements, the sedimentation and erosion, and give insights into the evolution of the German Central Graben. The base of the Zechstein Group reaches a maximum depth of 7800 m within the German Central Graben. Lateral thickness variations in the Zechstein reflect the extensive mobilisation of Zechstein salt. Complex rift-related structures, with the Central Graben as the main structural element, were found not later than the Early Triassic. Up to 3000-m thick Triassic sediments are preserved in the eastern German Central Graben of which 1800 m consist of Keuper sediments. The Lower Buntsandstein unit shows increasing thicknesses towards the southeastern study area, likely related to distinct lateral subsidence. As a consequence of uplift of the North Sea Dome, Middle Jurassic sediments were eroded in large parts of the northwestern German North Sea and are only preserved in the German Central Graben. The NNW–SSE oriented John Basin is another important structural element, which shows maximum subsidence during the Late Jurassic. In most parts of the study area Lower Cretaceous sediments are absent due to either erosion or non-deposition. Lower Cretaceous deposits are preserved in the Outer Rough Basin in the northwest and within the German Central Graben. Upper Cretaceous sediments are found at depths between 1500 and 3600 m, reaching a maximum thickness of approximately 1600 m on the Schillgrund High. Contraction and inversion of pre-existing Mesozoic faults during the Late Cretaceous is distinct at the Schillgrund Fault, i.e. the eastern border fault of the Central Graben. The Palaeogene is predominantly a period of strong basin subsidence. Within 37 Myrs, up to 1400 m of Palaeogene sediments were deposited in the northwesternmost part of the study area. Detailed mapping of salt structures enables a reconstruction of halokinetic movements over time and a deciphering of the influence of the Zechstein salt on the sedimentary evolution during the Mesozoic and Cenozoic. Increasing sediment thicknesses in rim-synclines indicate that most of the salt structures in the German Central Graben had their main growth phase during the Late Jurassic.

Impact of rain-fed cropping on the hydrology and fertility of alluvial clays in the more arid areas of the upper Darling Basin, eastern Australia

The impact of cropping on the hydrology and fertility of Vertosols in the northern Darling Basin (average annual rainfall >550 mm) has received much attention, together with the constraints placed on crop growth by naturally occurring subsoil salt stocks. These factors have not been quantified in the drier (450–550 mm), marginal cropping areas to the west. With widespread adoption of zero tillage technology and the potential for large increases in the capture and storage of rainfall in good seasons, mobilisation of salt could be exacerbated should crop water use be constrained by salt toxicity and/or nutrient deficiency. We investigated the size of salt stocks, historic deep drainage, and nutrient depletion under continuous cropping in the Grey and Brown Vertosols of the Walgett and Coonamble districts of north-western NSW. Soils collected from seven paired sites (cropped v. control native vegetation) showed chloride concentrations >500 mg/kg within 0–1.2 m, high exchangeable sodium percentage (~30%) at depth and deficiency in phosphorus, manganese and zinc. Soil total nitrogen decreased from an average stock of 4.9 t/ha at a rate of 0.008 t/ha.year under cropping within 0–0.1 m and soil carbon stocks decreased from 39 t/ha by 0.20 t/ha.year within 0–0.5 m.. Despite low rainfall, high evaporation and the large water-holding capacity of the cracking clays, there were significant downward shifts in chloride concentrations under cropping. Estimates of deep drainage under continuous cropping using chloride mass balance, chloride-front displacement and crop water-balance modelling with the Agricultural Production Systems Simulator (APSIM) generally agreed (range 0.1–2% of average annual rainfall). Simulations suggested that deep drainage may be increased 5–10-fold under zero-tillage winter cropping due to enhanced capture of rainfall by zero tillage compared with traditional practices. The associated flushing of salt from the root-zone together with correction of nutrient deficiency would enhance crop water use and productivity. Current methods indicate little storage in the subsoil for future deep drainage and that hydraulic conductivity is very low. Hence, the long-term effects of any increase in drainage rates, due to changes in cropping practices and/or climate, on the potential for salinisation of groundwater or transient water logging of the surface, are equivocal.

Cenozoic salt tectonics in the Officer Basin, Western Australia: implications for hydrocarbon exploration

The Neoproterozoic western Officer Basin has a total sedimentary fill of up to 8 km and a depositional history with similarities to other central Australian basins, particularly the Amadeus Basin. The size and remoteness of the basin has traditionally been an impediment to exploration, and only sparse seismic and well data are available. In such areas, potential field data can be a powerful exploration tool to assess petroleum prospectively. Salt distribution and mobilisation in the Officer Basin is poorly understood and has been significantly under-estimated due to a lack of quality seismic data. Examination of the existing aeromagnetic, gravity and seismic data, along with satellite and Shuttle Radar Topography Mission (SRTM) data, indicate that surface and shallow salt is abundant in the northern and central parts of the basin. Remobilisation of salt is greatest in the eastern part of the study area, decreasing towards the west, although the extent of salt occurrence to the west is unclear. Salt diapirs occur along structural trends; east to west in the northeastern (Gibson) part of the basin, and northwest to southeast in the central (Yowalga) area. Neotectonic features such as surface lineaments and recent earthquake data suggest that minor tectonic reactivation is occurring in the present day, and is consistent with a present-day stress orientation of approximately 095°. Miocene to recent stress orientations suggest that structures in the Gibson area may have been reactivated as right lateral faults, whereas those in the Yowalga area are reactivated as left lateral faults. Potential trap styles in the western Officer Basin include structural plays related to salt movement, such as drape folds, diaper overhangs, and thrusts. Late-stage movement of salt must, therefore, be considered when assessing the timing of migration pathways and possible seal breach. An improved understanding of the extent of salt in the Officer Basin, and the degree of reactivation during the Cenozoic, is vital for successful exploration in the region. Acquisition of high-resolution magnetic and gravity data would be a cost-effective exploration tool for better definition of salt and associated hydrocarbon traps.

Geophysical subsurface imaging for ecological applications

Ecologists, ecohydrologists, and biogeochemists need detailed insights into belowground properties and processes, including changes in water, salts, and other elements that can influence ecosystem productivity and functioning. Relying on traditional sampling and observation techniques for such insights can be costly, time consuming, and infeasible, especially if the spatial scales involved are large. Geophysical imaging provides an alternative or complement to traditional methods to gather subsurface variables across time and space. In this paper, we review aspects of geophysical imaging, particularly electrical and electromagnetic imaging, that may benefit ecologists seeking clearer understanding of the shallow subsurface. Using electrical resistivity imaging, for example, we have been able to successfully show the effect of land-use conversions to agriculture on salt mobilization and leaching across kilometer-long transects and to depths of tens of meters. Recent advances in ground-penetrating radar and other geophysical imaging methods currently provide opportunities for subsurface imaging with sufficient detail to locate small (≥5 cm diameter) animal burrows and plant roots, observe soil-water and vegetation spatial correlations in small watersheds, estuaries, and marshes, and quantify changes in groundwater storage at local to regional scales using geophysical data from ground- and space-based platforms. Ecologists should benefit from adopting these minimally invasive, scalable imaging technologies to explore the subsurface and advance our collective research.

New insights on diapirism in the Adriatic Sea: the Tremiti salt structure (Apulia offshore, southeastern Italy)

AbstractThe reinterpretation of public seismic profiles in the Adriatic offshore of Gargano (Apulia, southern Italy) allowed the detection of a kilometre‐scale salt‐anticline, the Tremiti diapir, within the larger Tremiti Structure. This anticline was generated by diapirism of Upper Triassic anhydrites within a thick Mesozoic to Quaternary sedimentary succession. Both internal stratal patterns and shapes of Plio‐Quaternary units, and the occurrence of an angular unconformity between early Tortonian and Pliocene rocks on the Tremiti Islands, suggest that halokinesis began during the late Miocene and is still active today. An ancient extensional SE‐dipping fault, cutting an older Mesozoic low‐amplitude anhydritic ridge, played an important role during salt mobilization, which was promoted by NW‐SE shortening. The diapir grew in the footwall of this fault, causing its upward propagation. In some places, the ancient fault served as a preferential channel for the upward migration of the anhydrites.

Onset of deep drainage and salt mobilization following forest clearing and cultivation in the Chaco plains (Argentina)

moisture content and 94% lower chloride stocks compared to dry forest (0.05 6 0.04 kg/m 2 versus 0.77 6 0.4 kg/m 2 ). Estimates of groundwater recharge based on the displacement of chloride peaks suggested values of 27–87 mm yr � 1 for agricultural soybean stands, and 10.4 mm yr � 1 for pastures. While hydrological shifts in the regional groundwater system are poorly monitored and understood, our findings show that it is potentially sensitive to land use changes and to salinization processes.

Growth of normal faults in multilayer sequences: A 3D seismic case study from the Egersund Basin, Norwegian North Sea

We investigate the structural style and evolution of a salt-influenced, extensional fault array in the Egersund Basin (Norwegian North Sea) through analysis of 3D reflection seismic and well data. Analysis of fault geometry/morphology, throw distribution and syn-kinematic strata reveal an intricate but systematic style of displacement and growth, suggesting an evolution of (1) initial syn-sedimentary fault growth contemporaneous with salt mobilization initiated during the Late Triassic, (2) cessation of fault activity and burial of the stagnant fault tips, and (3) subsequent nucleation of new faults in the cover above contemporaneous salt re-mobilization initiated during the Late Cretaceous, with downward propagation and linkage with faults. Stage 3 was apparently largely controlled by salt mobilization in response to basin inversion, as reactivated faults are located where the underlying salt is thick, while the non-reactivated faults are found where salt is depleted. Based on the 3D-throw analyses, we conclude that a combination of basement faulting and salt (re-) mobilization is the driving mechanisms behind fault activation and reactivation. Even though the sub- and supra-salt faults are mainly geometrically decoupled through the salt, a kinematic coupling must have existed as sub-salt faults still affected nucleation and localization of the cover faults.

Magnetic anomalies associated with salt tectonism, deep structure and regional tectonics in the Maritimes Basin, Atlantic Canada

AbstractThe structure and tectonic evolution of an evaporite basin are investigated in this case study, which combines the interpretation of magnetic data with the more commonly applied seismic reflection and gravity methods. The Maritimes Basin contains up to 18 km of Upper Palaeozoic sedimentary rocks resting on the basement of the Acadian orogeny. Carboniferous rocks are intensely deformed to the southeast of the Magdalen Islands as a result of deformation of evaporites of the Viséan Windsor Group. Short‐wavelength (<5 km) magnetic lineations define NNE‐ and ENE‐trending linear belts, coincident with the mapped pattern of salt structures. Magnetic models show that these lineations can be explained by the infill of subsidence troughs by high‐susceptibility sediment and/or the presence of basaltic rocks, similar to those uplifted and exposed on the Magdalen Islands. Additional shallow, magnetic sources are interpreted to result from alteration mineralization in salt‐impregnated, iron‐rich sedimentary rocks, brecciated during salt mobilization. Magnetic susceptibility measurements of samples from the Pugwash mine confirm the presence of higher susceptibility carnallite‐rich veins within salt units. Salt tectonism and basin development were influenced by the structure of the base group, the deepest regionally continuous seismic reflections (ca. 5–11 km), associated with an unconformity at the base of the Windsor Group, sampled at the Cap Rouge well. Salt structural evolution, formation of the magnetic lineations and geometry of the base group are associated with regional dextral transpression during basin development (late Carboniferous) and/or Alleghanian Orogeny (late Carboniferous to Permian). In this and similar studies, the effective use of magnetics is dependent upon the presence of rocks of high magnetic susceptibility in contrast to the low‐susceptibility salt bodies. In the absence of high‐susceptibility rocks, magnetic lows over the salt structures may be modelled, similar to commonly applied gravity techniques, to derive the internal structure and geometry.

Proposed water balance equation for municipal solid waste landfills in Jordan

This article presents a water balance equation for predicting leachate generation in municipal solid waste (MSW) landfills located in semi-arid areas, using the Akaider landfill in Jordan as an example. HYDRUS-2D/3D software was used to model the effect of co-disposal of wastewater into the landfill on the leachate production rates and for comparison with the results of the simulation of the proposed water balance equation parameters. A series of simulations was carried out for a 30-year period. The suggested water balance equation predicted that leachate will percolate to a depth of 50 m in the simulated period. The result indicates that the co-disposed wastewater plays a major role in controlling the rate and magnitude of the contaminants that percolate from the MSW leachate. As the initial water content of the waste increases, there is greater mobilisation of salts. The concentration of chloride at a given location increased and the time required for the chloride to reach this location decreased as a consequence. However, eliminating the co-disposed wastewater will significantly minimise leachate generation and decrease possible groundwater contamination. This equation is applicable to areas that have geological and hydrological properties similar to Jordan.

A review of the numerical modelling of salt mobilization from groundwater-surface water interactions

Salinization of land and water is a significant challenge in most continents and particularly in arid and semi-arid regions. The need to accurately forecast surface and groundwater interactions has promoted the use of physically-based numerical modelling approaches in many studies. In this regard, two issues can be considered as the main research challenges. First, in contrast with surface water, there is generally less observed level and salinity data available for groundwater systems. These data are critical in the validation and verification of numerical models. The second challenge is to develop an integrated surface-groundwater numerical model that is capable of salt mobilization modelling but which can be validated and verified against accurate observed data. This paper reviews the current state of understanding of groundwater and surface water interactions with particular respect to the numerical modelling of salt mobilization. 3D physically-based fully coupled surface-subsurface numerical model with the capability of modelling density-dependent, saturated-unsaturated solute transport is an ideal tool for groundwater-surface water interaction studies. It is concluded that there is a clear need to develop modelling capabilities for the movement of salt to, from, and within wetlands to provide temporal predictions of wetland salinity which can be used to assess ecosystem outcomes.

Geochemical assessments and classification of coal mine spoils for better understanding of potential salinity issues at closure

Coal mining wastes in the form of spoils, rejects and tailings deposited on a mine lease can cause various environmental issues including contamination by toxic metals, acid mine drainage and salinity. Dissolution of salt from saline mine spoil, in particular, during rainfall events may result in local or regional dispersion of salts through leaching or in the accumulation of dissolved salts in soil pore water and inhibition of plant growth. The salinity in coal mine environments is from the geogenic salt accumulations and weathering of spoils upon surface exposure. The salts are mainly sulfates and chlorides of calcium, magnesium and sodium. The objective of the research is to investigate and assess the source and mobility of salts and trace elements in various spoil types, thereby predicting the leaching behavior of the salts and trace elements from spoils which have similar geochemical properties. X-ray diffraction analysis, total digestion, sequential extraction and column experiments were conducted to achieve the objectives. Sodium and chloride concentrations best represented salinity of the spoils, which might originate from halite. Electrical conductivity, sodium and chloride concentrations in the leachate decreased sharply with increasing leaching cycles. Leaching of trace elements was not significant in the studied area. Geochemical classification of spoil/waste defined for rehabilitation purposes was useful to predict potential salinity, which corresponded with the classification from cluster analysis based on leaching data of major elements. Certain spoil groups showed high potential salinity by releasing high sodium and chloride concentrations. Therefore, the leaching characteristics of sites having saline susceptible spoils require monitoring, and suitable remediation technologies have to be applied.

Calcium hydroxide nanosols for the consolidation of porous building materials - results from EU-STONECORE

The main idea of the European STONECORE R&D project (2008 to 2011) was to develop and evaluate nano materials for the use in refurbishment and conservation of historic monuments. A set of different calcium hydroxide (“lime”) nanoparticles dispersed in alcohols (CaLoSiL®) available on the market were tested. The general advantages attributed to alcoholic lime dispersions were: compatibility of the consolidant with the original building material, no limitation of penetration due to the particle size, and no mobilisation of soluble salts. The paper mainly reports the evaluation of lime nanosols for consolidation of lime mortar, gypsum stucco, and mural painting layers. In order to achieve a penetration behaviour which is adequate to the pore structure of the substrate, the composition of the nanosol as well as its application procedure had to be adjusted. This could be achieved by dilution, additives, or after-treatment of the surface. Apart from structural strengthening of porous structures the lime nanosols were tested for treatment of larger defects such as fissures, cracks, detachment, and delamination. For this purpose the nanosols were modified with additives, fillers, and aggregate. The developed lime nanosol formulations were applied to test sites at three historic monuments with promising results. A ‘modular system’ was developed to meet all these conservation needs. These materials showed sufficient adhesive strength. They proved applicable for the consolidation of severely cracked limestone as well.

Accumulation and Mobility of Salts in Soil as Influenced by Primary Biomethanated Spentwash

A soil column laboratory experiment was carried out at the central campus, Mahatma Phule Agricultural University, Rahuri, India during 2008–2009 to study the accumulation and mobility of salts in Typic Haplusterts as influenced by primary biomethanated spentwash (PBSW). The PBSW was applied in three different levels (0.5, 1.0, and 2.5 cm) and then tap water with low salinity and low sodium hazard (C1S1 class) was used to carry out leaching in four different levels of water at the pore volume of soil (WPVS) (0.5, 1.0, 1.5, and 2.0). The electrical conductivity (EC) in the soil increased significantly with increasing levels of PBSW and decreased with increasing levels of WPVS in surface (0–15 cm deep) and subsurface (15–30 cm deep) soil layers. The exchangeable calcium (Ca2+), magnesium (Mg2+), and potassium (K+) increased, whereas exchangeable sodium (Na+) decreased with increasing levels of PBSW and WPVS in surface and subsurface layers of soil. The organic carbon content increased with increasing levels of PBSW and decreased with increasing levels of WPVS in both the soil layers. The cation exchange capacity (CEC) increased with increasing levels of PBSW and WPVS in both the soil layers. The exchangeable sodium percentage (ESP) decreased with increasing levels of PBSW and WPVS over the initial values of soil in both the layers. The pH of saturated paste (pHs) was reduced and electrical conductivity of extract (ECe) was increased with increasing levels of PBSW and WPVS in both the layers. The Na+ content of saturation paste extract increased significantly with increasing levels of PBSW and WPVS in both the soil layers.