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With the aim of better directing the polycondensation of oligomers during the synthesis of amorphous aluminosilicate xerogels by the sol-gel process using Na2SiO3, we reinforced the sols with K+ counterion and studied its effect on the physicochemical and structural properties of the xerogels using XRD, FTIR, N2 physisorption, SEM, EDX, and TGA techniques as well as quantitative analysis of the acid sites by N-butylamine adsorption followed by potentiometric titration. Based on the results, the introduction of K+ generated xerogels with good porosity and conferred resistance to matrix cracking. The amorphous character of the xerogels did not change after adding K+. FTIR spectra showed that the composition of the xerogels was improved after the addition of K+. Cation exchange and sulfur removal were much more efficient in the presence of K+ which improved the acidity of the xerogels. The best percentages of Si and Al were observed at the Na+/K+ ratios of 4 and 1.The enhanced xerogel prepared with Na+/K+ ratio of 1 gave a biodiesel yield of 80.44% at the optimum parameters and was used for three reaction cycles without significant loss of biodiesel yield. [ABSTRACT FROM AUTHOR]

The transport characteristics of manganese was investigated by soil columns experiments and provide essential data for aquifer remediation and groundwater protection in Yinchuan City. Soil column experiments involved a solution of manganese chloride in which the chloride ion was the chemical tracer. In the two column experiments, the breakthrough curve (BTC) for Cl– revealed the average linear flow velocity (2.937 and 3.921 cm/h) and longitudinal dispersivity (8.52 and 40.09 cm) of the sediment. The BTC of Mn2+ showed a significant delay compared to Cl–. The adsorptive equilibrium isotherm experiments showed that Ca2+ was the main desorption cation in the cation exchange process. The nonlinear retardation factor Rf (RfTM-1 = 13.97, RfTS-1 = 12.89) of Mn2+ is derived from thermodynamic principles. [ABSTRACT FROM AUTHOR]

This research investigated on the hydrochemistry and salt-fresh mixing of the groundwater in the aquifers nearby Sirjan salt playa near Sirjan city, Kerman province, Iran. Therefore, 62 groundwater samples were collected from Sirjan salt playa, Kheyrabad plain, Chahderaz plain and Golgohar mining area. Chemical diagrams, ion ratios, statistical method and mixing applied to hydochemical investigation. The water samples were then categorised into four water types; i.e. NaCl, Na-Ca-Cl, Na-SO4 and Ca-HCO3. The presence of salt playa in the area has led to the phenomenon of mixing between saline and freshwater. Saltwater intrusion occurred from 0.01 to 29% in the groundwater and it destroyed the quality of groundwater in the study area. Most percentages of intrusion were seen in Golgohar mine area and which is due to overexploitation of groundwater by dewatering process in the pit, where the saltwater intrudes from hard rock aquifer by upconing phenomena. Results showed that the actual concentrations of Na+ are less than expected concentrations; while for Mg2+ and Ca2+ their actual concentrations have been increased versus expected concentrations and it suggests cation exchange of Na+ by Mg2+ and Ca2+ in the aquifers of the study area. [ABSTRACT FROM AUTHOR]

A novel C/NiCo2O4 composite derived from Ni-Co-MOF compound is reported. A typical hydrothermal method followed with cation exchange was employed to get the nickel-cobalt binary metal-organic framework. After annealing the Ni-Co-MOF, the carbon containing NiCo2O4 composite was obtained successfully. The obtained C/NiCo2O4 anode displays superior electrochemical performance with initial specific capacity of 889 mAh g−1 at the current rate of 0.2 C, and 740 mAh g−1 at 0.2 C after 300 cycles. The cation exchange method shows promising application to design other binary/ternary metal oxides for Lithium-ion batteries and supercapacitors. [ABSTRACT FROM AUTHOR]

In this work, we reported results obtained during experimental tests to introduce a new approach to the treatment of dredging sludge polluted by mercury. A slurry of dredging sludge was treated by cationic exchange procedures both at ambient temperature and distilled at 393K with the aid of some different exchange salts: three inorganic (NaCl, CaCl2, and CaI2) and two organic Tetrabutylammonium chloride [(C4H9)4NCl] and Ethyl Viologen diiodide (1,1′-Dietil-4,4′-bipyridinium diiodide) [C14H18I2N2], having different cationic exchangeable part and different molecular weights. A similar (15% w/w) solution was used to treat mercury-polluted sludge considering 2, 24, and 48 h of reaction time. The removal efficiencies of the inorganic/low molecular weight monovalent salts were minimal at the tested temperatures, while higher removal was reached when CaI2 and Viol-I2 were used at ambient temperature with maximum treatment efficiencies over 70% in 48 h treatment. A recovery/reuse of the exchanging solutions was also tested finding good recovery potential of the salt slurry. [ABSTRACT FROM AUTHOR]

This work demonstrates a method to form 1-D ethylammonium lead iodide (EAPbI3) thin-films by dimensional down-conversion of 3-D methylammonium lead iodide (MAPbI3) perovskite. The process leverages cation-exchange that occurs during exposure to ethylamine vapor and subsequent annealing. Based on the extensive materials characterization, a detailed mechanism of the transformation is proposed. The transformation also improves the morphology of the films, yielding compact EAPbI3 films with roughness of 50-100 nm, low-pin-hole density, and grain-size of 1-3 µm. The process can be used to fabricate various EAPbI3 optoelectronic devices. Since lower dimensional perovskites are more stable against moisture than MAPbI3, the process can also be used to fabricate 3D-1D graded perovskite interfaces for materials study and to stabilize MAPbI3 solar cells with a protective outer layer of EAPbI3. [ABSTRACT FROM AUTHOR]

With increasing demand and prospective scarcity of rare earths, the capacity to separate these elements with high selectivity is a critical challenge in hydrometallurgy. We evaluate in this article the capacity of N,N,N',N'-tetra-n-octyl diglycolamide (TODGA) to separate lanthanides in both organic solvent and ionic liquids (ILs) using the holdback reagent diethylenetriaminepentaacetic acid (DTPA) in the aqueous phase. Totally, 10 imidazolium-based ILs with various hydrophobicity were studied herein: [Cnmim][NTf2] and [Cnmim][BETI] (n = 2,4,6,8,10). In this process, selectivity for light lanthanides was obtained owing to a competitive complexation between TODGA and DTPA. [ABSTRACT FROM AUTHOR]

Functionalized ionic liquid based on quaternary ammonium salt was investigated for the specific task of the efficient extraction of f block elements in different oxidation states. It deals with the investigation of extraction efficiency, mechanism, speciation and associated kinetics and thermodynamics. The extracted species of Pu4+, PuO22+, Am3+, Eu3+were found to be Pu(Hptha)(H2O)63+, PuO2(Hptha)(H2O)2+, Am(Hptha)(H2O)72+, Eu(Hptha)(H2O)72+, respectively where (Hptha)−is the anionic part of the ionic liquid. Effect of radiation exposure on the performance of the ionic liquid was also investigated. The suitable back extraction procedure from the ionic liquid phase was developed using aqueous soluble complexing agents. [ABSTRACT FROM AUTHOR]

Groundwater pollution by nitrate from agricultural fields is a worldwide problem. To improve the understanding of nitrate transport processes through volcanic ash soils overlying groundwater aquifers, salt sorption experiments were performed. Salt sorption is the process that involves the simultaneous use of cation and anion adsorption mechanisms without changing the pH. Prepared six different concentrations of potassium chloride (KCl) solutions were mixed with soil samples. Anion and cation contents of the liquid and solid phases were determined. Experiments were performed in triplicate of six kinds of KCl solutions for three types of soils. Thus, total 54 of samples were analyzed. Relationships between ionic strength and sorption capacity increments of cations and anions were determined. The results show that if ionic strength of the infiltrating solution to the volcanic ash soil is known, the ECEC (effective cation exchange capacity) and EAEC (effective anion exchange capacity) can be reliably estimated. The resulting prediction equations can be included to improve reactive transport simulation models. Consequently, it will be possible to better understand solute transport with changing sorption capacity for the solid soil phase. [ABSTRACT FROM AUTHOR]

The recovery of252Cf from palladium-252Cf cermet wires was investigated to determine the feasibility of implementation into the cermet wire production operation at the Radiochemical Engineering Development Center at Oak Ridge National Laboratory. The dissolution of Pd wire in 8MHNO3and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment from 0.176 mL/mg down to 0.019 mL/mg resulted in little change in the kinetics of dissolution. A successful separation of153Gd, a surrogate for252Cf, from Pd was demonstrated using ion exchange chromatography. [ABSTRACT FROM PUBLISHER]

A method was developed for simultaneous determination of four trisubstituted imidazolium ionic liquid cations (1-ethyl-2,3-dimethylimidazolium, 1-propyl-2,3-dimethylimidazolium, 1-butyl-2,3-dimethylimidazolium, 1-pentyl-2,3-dimethylimidazolium) by ion chromatography using a carboxylic acid cation exchanger bonded to a silica-based column and direct (nonsuppressed) conductivity detection. The effects of the type of eluents, organic acid concentration, acetonitrile volume fraction, and column temperature on the cations retention were investigated. The optimal conditions for the method were 5 mmol L−1methanesulfonic acid +10% acetonitrile as an eluent, 1.0 mL min−1flow rate, and a column temperature of 30°C. The detection limit (S/N = 3) were 0.82–2.39 mg L−1for the cations. The method was validated, accurate, and reproducible. This method was successfully applied to determine trisubstituted imidazolium ionic liquid cations in spiked tap water. The octanol–water partition coefficients (Kow) of these four trisubstituted imidazole substances were also reported in this study. [ABSTRACT FROM AUTHOR]

Detailed chemical studies on transactinide elements will clarify their characteristic properties caused by strong relativistic effect. In this work, to realize chemical study on transactinide element105Db, cation exchange, and solid-liquid and liquid-liquid extractions of micro amounts of Nb, Ta (homologues of Db), and Pa (pseudo homologue) by Aliquat 336 were performed employing hydrochloric acid. Clearly different chloride complex formations and distribution reaction kinetics were observed among these elements, and the present results are useful for studying the chemical properties of Db. Based on these results, we propose suitable experimental conditions for Db. [ABSTRACT FROM PUBLISHER]

Ciprofloxacin (CIP) adsorption on montmorillonite was investigated using structurally related probing compounds phenylpiperazine (PP) and fluorochloroquinolone carboxylic acid (FCQCA). Desorption of the equivalent amounts of exchangeable cations accompanying PP and CIP adsorption on montmorillonite suggested that cation exchange was the major adsorption mechanism for the CIP adsorption under acidic to neutral conditions, and the piperazine amine group was responsible for the cation exchange interaction. In contrast, the adsorption of CIP and FCQCA on montmorillonite indicated that hydrogen bonding between the keto carbonyl group and coordinated water in the interlayer of montmorillonite was mainly responsible for the CIP adsorption in alkaline aqueous solution as evidenced by Fourier transform infrared analyses. X-ray diffraction analyses demonstrated that both cation exchange and hydrogen bonding between the keto carbonyl group and coordinated water lead to the intercalation of CIP in montmorillonite. [ABSTRACT FROM AUTHOR]

The bentonite barrier is an essential part of a safe spent fuel repository in granitic bedrock. One of the most important safety functions of bentonite buffer is to limit groundwater flow so that all mass transport takes place by diffusion. In this work a new mathematical model was developed to define the transport of ions inside the bentonite, where there are bound interlayer water and free extra layer water and sorption capability. This model is tested in a specified geometry and calculated by two numerical platforms--Numerrin and COMSOL Multiphysics--and compared to the original TOUGHREACT model. The model comparison was not a straightforward task because of different approaches in the model setup. Therefore, all the equations are written down, and parameterization is done to create model descriptions near each other. The developed model adapts easily, and there are many new ideas to be tested in bridging the gap between performance assessment and real systems. [ABSTRACT FROM AUTHOR]

Adsorbent for strontium (Sr2+) ion removal was prepared from orange waste generated in an orange juice factory. The orange juice residue (OJR) was treated with lime water to prepare saponified orange juice residue (SOJR). The energy dispersive X-ray (EDX) spectroscopic analysis revealed that substitution of Ca2+ions in SOJR by Sr2+ions takes place during the adsorption process. The adsorption of Sr2+ions onto SOJR was fast and strongly pH dependent. Maximum adsorption occurred at pH higher than 5. The adsorption isotherm study showed maximum adsorption capacity of SOJR for Sr2+ion was 833.4 mmol/kg. Equimolar amount of Ca2+was found to be released from SOJR during Sr2+adsorption also indicating that adsorption of Sr2+on SOJR takes place according to the Ca2+substitution reaction by cation exchange mechanism. Thus, the adsorption gel prepared in this study can be a promising adsorbent to remove Sr2+from aqueous solution. [ABSTRACT FROM AUTHOR]

The mineral carbonation method is still a challenge in practical application owing to: (1) slow reaction kinetics, (2) high reaction temperature, and (3) continuous mineral consumption. These constraints stem from the mode of supplying alkaline earth metals through mineral acidification and dissolution. Here, we attempt to mineralize gaseous carbon dioxide into calcium carbonate, using a cation exchange reaction of vermiculite (a species of expandable clay minerals). The mineralization is operated by draining NaCl solution through vermiculite powders and continuously dropping into the pool of NaOH solution with CO2gas injected. The mineralization temperature is regulated here at 293 and 333 K for 15 min. As a result of characterization, using an X-ray powder diffractometer and a scanning electron microscopy, two types of pure CaCO3polymorphs (vaterite and calcite) are identified as main reaction products. Their abundance and morphology are heavily dependent on the mineralization temperature. Noticeably, spindle-shaped vaterite, which is quite different from a typical vaterite morphology (polycrystalline spherulite), forms predominantly at 333 K (∼98 wt%). [ABSTRACT FROM PUBLISHER]

Imogolite flocculates under alkaline conditions even though the net charge is considerably negative. To clarify the reason for this contradiction, we measured the charge characteristics of imogolite with an ion-exchange method using sodium ions (Na+) and chloride ions (Cl−) as index ions, and estimated its electric field intensity at the outer surface using Gauss’ law and the structural model of imogolite. The result showed that the electric field intensity of negative charge at the outer surface was about half of that at the inner surface. Further, we discussed that if cations could easily enter the imogolite tube, the electric field of negative charge would be drastically weakened due to the neighboring cations and, consequently, the outer surface would become electrically indifferent. If so, not only the reason for imogolite flocculation under alkaline conditions, but also the reason for imogolite dispersion at the point of zero net charge would be explained consistently. The reason for imogolite dispersion at the point of zero net charge was considered to be that the colloidal stability of imogolite would be affected only by the positive charges that appear on the outer surface of the tube. Finally, the hydrated sodium ions were considered to move in and out of the imogolite tube freely. [ABSTRACT FROM PUBLISHER]

Montmorillonite layered silicate has been commonly used to reinforce polymer matrices. Due to its swelling in water, organic modification of the mineral surface is easily achieved which makes the surface compatible with polymers. Other minerals like mica and vermiculite though can also lead to high aspect ratio platelets in nanocomposites, but they do not swell in water owing to much stronger electrostatic forces of attraction holding their platelets together (layer charge density >0.5 eq · mol−1in comparison with 0.25–0.5 eq · mol−1for montmorillonite). In current study, milling, delamination and cation exchange processing of mica and vermiculite minerals has been reported to explore their potential as reinforcement materials. Wet grinding and subsequent sieving of the coarse minerals led to fine-sized particles suitable to perform chemical delamination in water. The delamination process resulted in Li-mica and Na-vermiculite with enhanced access to the interlayer cations, thus, higher CEC. Successful surface modification of the delaminated minerals with alkyl ammonium ions could be achieved which resulted in significant enhancements in their basal plane spacing. Peak degradation temperatures of 260°C were measured for C18 and 2C18 modified vermiculite, whereas 300°C and 275°C were observed respectively for C18 and 2C18 modified mica minerals which make them suitable for compounding with polymers at high temperature. [ABSTRACT FROM AUTHOR]

Relationships between metal chelate stability, ligand basicity, and metal ion acidity are reviewed and the general applicability is illustrated by linear correlations between aqueous stability constants and ligand pKa values for 35 metals with 26 ligands. The results confirm that most individual ligands of this type exhibit a stability ordering that correlates with the Lewis acidity of the metal ion. It is concluded that the general metal ion selectivity exhibited by liquid-liquid oxoacid extractants such as carboxylic acids, β-diketones, and organophosphorus acids reflects the intrinsic affinity of the metal ion for the negative oxygen donor ligand. [ABSTRACT FROM AUTHOR]

Magnetic nanoparticles with cation exchange functionality (MNCX) are combined with an Aqueous Micellar Two-Phase System (AMTPS) based on the nonionic surfactant Eumulgin ES for the purpose of protein separation. As proof of principle the positively charged protein lysozyme is separated from the negatively charged protein ovalbumin with a purity of approximately 100%. In comparison with the application of the MNCX alone, the presence of Eumulgin ES reduced the amount of lysozyme bound; however, the amount of eluted lysozyme stays the same. The advantage of applying the AMPTS is that the MNCX are easily handled as they partition completely into the dispersed phase of the system while the applied proteins partition almost entirely to the continuous phase. [ABSTRACT FROM PUBLISHER]

Finnish spent nuclear fuel final disposal is planned to be based on the Kärnbränslesäkerhet 3-Vertical concept, which was originally planned for fractured crystalline bedrock. Within this concept, the role of the bentonite buffer is considered central. The aim of the study was to model the evolution of the final repository during the thermal phase (heat-generating period of spent fuel) when the bentonite is initially only partially saturated. There is an essential need to determine how temperature influences saturation and how both of these factors affect the chemistry of bentonite. In this study the Long-Term Test of Buffer Materials A2 parcel test at the Äspö hard rock laboratory in Sweden was modeled using TOUGHREACT code. The results focused on the following phenomena occurring in the bentonite: cation exchange, changes of bentonite pore water, mineral alterations, saturation, and pressure changes in bentonite buffer. The results show similarity with experimental data. However, the results are open to questions, and further study is needed to confirm the validity of the results. Differences between modeled and experimental results can be explained, for example, so that the experimental results are not from the fracture position as our one-dimensional model assumes. [ABSTRACT FROM AUTHOR]

A new HPLC method was developed for determination of papaverine in a papaverine naturally photooxidized solution using a Duet C18/SCX column. The mobile phase used was a mixture of phosphate buffer (pH = 3.80) and acetonitrile in 40:60 ratio. The compounds identified were: papaverinol, papaveraldine, papaverine, and pyrrocolonium ion. Very good resolutions, peak shapes, and asymmetries were obtained. An ion exchange experiment was developed in order to identify and separate the pyrrocolonium ion. This was retained completely by a cation exchange resin in its Na+ form, while papaverine, papaverinol, and papaveraldine were retained more or less, due to a retention explained by a combined ion exchange-solvent extraction mechanism. Voltammetric studies showed that natural photooxidation of papaverine occurs in three irreversible steps and yields to stable compounds in solution. [ABSTRACT FROM AUTHOR]

An adequate knowledge of the physico-chemical properties and interaction of cations with soils is a critical research need for developing improved understanding of sustainable agricultural practices. This work therefore focuses on the study of the physico-chemical properties and equilibrium thermodynamics of adsorption of cations on Ferric Luvisols from Western Nigeria. All soil samples showed moderately similar characteristics in terms of the physico-chemical parameters investigated. The pH of the various soil samples in water varied from 6.70-7.40, typical of soils found in humid regions. The organic matter contents were low, in the range of 0.93-3.23%. The exchangeable bases and cation exchange capacity were also moderately low, with the latter having a range of 1.42-1.99 cmolc/kg. This may be attributed to their low clay content (range 8.32-18.32%). The exchange reactions of calcium (Ca) and potassium (K) at 30°C and 60°C were studied. Thermodynamic parameters derived from experimental results were determined for K-Ca and Ca-K exchange reactions on the soil samples. The selectivity coefficients (Kc) of the Ca-K and K-Ca exchange were found to decrease with increase in K and Ca-loading. The decrease was more pronounced for K-Ca exchange. The low selectivity coefficients with an increase in K loading indicated a greater affinity of the soils for Ca than K. The high equilibrium constants and the negative values of the standard free energy (ΔGdeg;) for the exchange of K for Ca revealed a preference of all the soils for Ca relative to K ions. Also ΔGdeg; values for the reaction Ca-soil to K-soil were positive, which indicated the reluctance of Ca-soil to be converted to K-soil. [ABSTRACT FROM AUTHOR]

Two separation methods, aqueous two-phase (ATP) partitioning and cation-exchange chromatography, were compared as alternative methods for the recovery of recombinant dog gastric lipase (r-DGL) from extracts of transgenic corn endosperm. r-DGL is a hydrophobic, acid-stable protein targeted for stable expression in endosperm. Polyethylene glycol (PEG) - salt ATP system parameters of PEG molecular weight, phase-forming salt, NaCl addition, Triton X-100 concentration and phase ratio were adjusted to achieve favorable partitioning. The purification factor and yield of r-DGL in the bottom phase of a PEG 3350 (14.2%)-Na2SO4 (8.5%)-NaCl (0.5%)-Triton X-100 (2 mM) system at pH 4 were 1.5 and 80%, respectively. A higher purification factor of 2.3 and nearly 100% yield of r-DGL was obtained in the top phase of a PEG 3350 (9.4%)-phosphate (14.3%)-NaCl(1.5%)-Triton X-100 (2 mM) system at pH 4.0. The yield, purification factor, and concentration factor were 90%, 7.7, and 3.6, respectively, for the alternative of cation-exchange on CM-Sepharose. Countercurrent ATP partitioning with 3-7 stages was calculated to achieve a purification factor equivalent to that from cation exchange but with a lower concentration factor. While the cation exchange was favored on this basis, the two approaches were close enough that further optimization and economic analysis would be needed to be definitive. [ABSTRACT FROM AUTHOR]

Dissolved aluminium was fractionated in the field and the laboratory using a cation-exchange method. Although absolute differences between results obtained from field and laboratory fractionations were generally small, relative differences, expressed as the ratio between labile aluminium determined after laboratory fractionation (Al ll ) and that obtained after field fractionation (Al lf ) could be large. The differences found were not statistically significant, although this may simply reflect the spread in the results. Al ll /Al lf had no apparent relationship with the temperature difference between the field and the lab. Although some significant correlations were found between Al ll /Al lf and H + , no significant correlations were found with the equivalent relative difference in {H + } between the lab and the field; nor was any significant correlation found with dissolved organic carbon. [ABSTRACT FROM AUTHOR]

The diagnosis of the different forms of thalassemia is one of the important applications of analysis of globin chains. These analyses are done by high performance liquid chromatography (HPLC) using a MONO-S cation exchange column and ether is used for washing the globin powder in the final step. The presence of peroxide impurities in ether could change the structure of the globin chains. In the chromatograms, these modified globins appear as separated peaks next to the unmodified globin peaks. In these cases, the a/ß ratio exceed by artifact the correct value. Our study demonstrates that diagnostic centers should ensure that the ether they use is pure. [ABSTRACT FROM AUTHOR]

Colloidal semiconductor nanocrystals, with intense and sharp-line emission between red and near-infrared spectral regions, are of great interest for optoelectronic and bio-imaging applications. The growth of an inorganic passivation layer on nanocrystal surfaces is a common strategy to improve their chemical and optical stability and their photoluminescence quantum yield. In particular, cation exchange is a suitable approach for shell growth at the expense of the nanocrystal core size. Here, the cation exchange process is used to promote the formation of a CdS passivation layer on the surface of very small PbS nanocrystals (2.3 nm in diameter), blue shifting their optical spectra and yielding luminescent and stable nanostructures emitting in the range of 700–850 nm. Structural, morphological and compositional investigation confirms the nanocrystal size contraction after the cation-exchange process, while the PbS rock-salt crystalline phase is retained. Absorption and photoluminescence spectroscopy demonstrate the growth of a passivation layer with a decrease of the PbS core size, as inferred by the blue-shift of the excitonic peaks. The surface passivation strongly increases the photoluminescence intensity and the excited state lifetime. In addition, the nanocrystals reveal increased stability against oxidation over time. Thanks to their absorption and emission spectral range and the slow recombination dynamics, such highly luminescent nano-objects can find interesting applications in sensitized photovoltaic cells and light-emitting devices. [ABSTRACT FROM AUTHOR]

Regular wood ash recycling has been suggested as a precautionary measure for preventing acidification and development of under-balanced nutrient budgets in Swedish forest ecosystems, particularly in areas where whole-tree harvest is being practised. Granulation can be used as a means of reducing the reactivity of the ash. In two experiments on podzolic soils, the humus layer and the upper 15 cm of the mineral soil were sampled 2 years after applying a well-hardened, granulated wood ash at rates of 1 to 6 ton ha-1. The timing potentialof the ash corresponded to 28% CaO. Cation exchange capacity, pH andbase saturation were positively correlated with ash dose, and exchangeable acidity was negatively correlated with ash dose, in the upper part of the humus layer at both sites. The total amount of exchangeable base cations (kmolc ha-1) had, on average, increased by about 2 x (square root of) dose (ton ha-1) in the sampled soil compartment. A comparison with previous studies suggests that granulated ash should generally cause a less drastic pH increase compared with loose ash of the same origin. [ABSTRACT FROM AUTHOR]

Deposition of acidifying compounds (sulphur and nitrogen) in combination with the harvest of forest biomass leads to diminished amounts of exchangeable base cations and micronutrients in soil. A larger lossof base cations than is supplied by weathering and deposition leads to diminished production capacity of the soil. This might be compensated by the spreading of wood ash, thereby returning mineral nutrientsto forest soils. The purpose of this study was to illuminate variation between different wood ashes with respect to acid neutralizing capacity (ANC), base cations and mineral nutrient solubility. This has been done as a laboratory leach study, Leaching was carried out by mixing wood ash and distilled water adjusted to pH 4.0 (ratio 1 : 2000).Leachate was poured off after 24 h and new solution added. Leachate was analysed. This procedure, with daily change of solution, continued for 30 days. Concerning ANC, tested ash products were more reactiveduring short time tests than lime products. Rates of leaching variedbetween different substances in the ashes. Mean values for totally leached amounts from ashes were 79%, 53%, 27%, 22%, and 48% for Ca, Mg, Mn, Al and P, respectively. Particle size was less important for ANC and leached amounts from ashes compared to that for lime products. [ABSTRACT FROM AUTHOR]

The effects of SO2 and heavy metal emissions derived fromCu-Ni Smelters in the Kola Peninsula, NW Russia, on soil acidity parameters in the western parts of the Kola Peninsula and Finnish Lapland are presented. Organic layer samples were collected at 39 sampling plots along lines running to the west from two emission point sources(Monchegorsk, Nikel) in the Kola Peninsula. The tree cover on the sample plots consisted of Pinus sylvestris L. growing on dry sites. Thesoil type was podsolic and soil texture sorted sand. The effects of emissions from the Monchegorsk smelters on the properties of the organic layer along the sampling lines can be divided into two zones: up to a distance of approx. 100 km from the smelters there were distinctgradients in the total Cu and Ni and exchangeable Al concentrations,and to some extent in base saturation (BS), but not in extractable Sconcentrations, while at greater distances to the west the emissionsappear to have had no detectable effects. Despite the very low BS values close to the Monchegorsk smelter, there were no differences in pH or in exchangeable H+ concentrations with increasing distance from the smelter. Total Cu and Ni concentrations were elevated close to the Nikel smelter but were considerably lower than those at corresponding distances from Monchegorsk. Extractable S concentrations along the Nikel line were not affected by emissions. BS showed a decrease with decreasing distance to Nikel, but there were no clear relationships for pH or exchangeable Al. In contrast, exchangeable H+ increased with decreasing distance to the point source. A reduction in BS in heavy-metal polluted soils should not be taken as anabsolute indication of soil acidification caused by acidic deposition, because metals can also effectively displace cations from cation exchange sites. [ABSTRACT FROM AUTHOR]