High Cation Exchange Capacity Research Articles

EVOLUTION OF SOIL CHEMICAL VARIABLES IN AN ORGANIC CELERY CROP DURING THE CONVERSION PERIOD TO ORGANIC FARMING

For this study two fertilisation assays were carried out in an experimental field. The first assay (F1) used a sheep manure amendment, following the stipulations of European regulations concerning organic agriculture practices, and the second assay (F2) followed conventional agricultural practices of the area using inorganic fertilizers (313; 37 and 566 kgha-1 of N, P and K, respectively). Over a three-year period, samples of the arable soil layer were taken monthly in order to analyse the soil properties as indicators of soil quality (organic carbon, total Kjeldahl nitrogen, C:N ratio, Olsen P, electrical conductivity, pH in water and 1M KCl, cation exchangeable capacity, and exchangeable bases (Mg, K and Na). The experimental plot managed using organic agriculture techniques showed significantly better conditions for crop development than the conventionally managed plot: higher quantities of organic matter (22.4 and 17.4 gkg-1, respectively) and nitrogen ( 3.0 and 2.5 gkg-1, respectively), a higher cation exchange capacity(14.4 and 12.2 cmol(+)kg-1, respectively) and greater availability of phosphorus ( 45.4 and 27.1 mgkg-1). No significant differences were observed as regards pH (8.0 in both plots) or the C/N ratio (7.7 and 7.1, respectively). Despite the short trial period of only three years, these results suggest that the agronomic model based on organic agriculture has a beneficial effect on soil properties and contributes to the function of soil as C sink.

Chemical evaluation of chars produced by thermochemical conversion (gasification, pyrolysis and hydrothermal carbonization) of agro-industrial biomass on a commercial scale

Technologies for agro-industrial feedstock utilization such as pyrolysis, gasification and hydrothermal carbonization at industrial scale develop rapidly. The thermochemically converted biomasses of these production technologies have fundamentally different properties controlled by the production technology. This is reflected by general properties such as pH or elemental composition. The 13C NMR spectroscopy, scanning electron microscopy and energy-dispersive X-ray spectroscopy and black carbon results confirmed these observations showing that hydrochars have lower proportions of aromatic compounds than biochars (less stable) but are rich in functional groups (higher cation exchange capacity) than biochars. Analyses of pollutants indicate that polycyclic aromatic hydrocarbons as well as dioxin contents of most samples were under the threshold values recommended by International Biochar Initiative and European Biochar Certificate. In conclusion, biochars and hydrochars are entirely different from each other and these materials will probably have a complementary reaction in a soil environment.

Statistical evaluation of the influence of soil properties on recoveries and matrix effects during the analysis of pharmaceutical compounds and steroids by quick, easy, cheap, effective, rugged and safe extraction followed by liquid chromatography–tandem mass spectrometry

Numerous chemical products are dispersed in our environment. Many of them are recognized as harmful to humans and the ecosystem. Among these harmful substances are antibiotics and steroid hormones. Currently, very few data are available on the presence and fate of these substances in the environment, in particular for solid matrices, mainly due to a lack of analytical methodologies. Indeed, soil is a very complex matrix, and the nature and composition of the soil has a significant impact on the extraction efficiency and the sensitivity of the method. For this reason a statistical approach was performed to study the influence of soil parameters (clay, silt, sand and organic carbon percentages and cation exchange capacity (CEC)) on recoveries and matrix effects of various pharmaceuticals and steroids. Thus, an analysis of covariance (ANCOVA) was performed when several substances were analyzed simultaneously, whereas a Pearson correlation was used to study the compounds individually. To the best of our knowledge, this study is the first time such an experiment was performed. The results showed that clay and organic carbon percentages as well as the CEC have an impact on the recoveries of most of the target substances, the variables being anti-correlated. This result suggests that the compounds are trapped in soils with high levels of clay and organic carbon and a high CEC. For the matrix effects, it was shown that the organic carbon content has a significant effect on steroid hormones and penicillin G matrix effects (positive correlation). Finally, interaction effects (first order) were evaluated. This latter point corresponds to the crossed effects that occur between explanatory variables (soil parameters). Indeed, the value taken by an explanatory variable can have an influence on the effect that another explanatory variable has on a dependent variable. For instance, it was shown that some parameters (silt, sand) have an impact on the effect that clay content has on recoveries. Besides, CEC and silt affect the influence that organic carbon percentage has on matrix effect. This original approach provides a better understanding of the complex interactions that occur in soil and could be useful to understand and predict the performance of an analytical method.

Characterization of Pakistani purified bentonite suitable for possible pharmaceutical application

The aim of this study is to assess the suitability of Pakistani bentonite for its possible pharmaceutical use in raw and purified forms. The purified samples were obtained by two different methods i.e. simple sedimentation and classical NaCl treatment. Prior to bentonite application in pharmacy, it is imperative that they must comply with some general features as high mineral, chemical and microbial purity. The physicochemical properties especially gel formation and swelling capacity are also important to be tested to investigate its specific use. The mineralogical study reveals that the raw sample is bentonite containing mainly montmorillonite with minor contents of kaolinite, illite and quartz. The quartz impurities were removed by the purification methods as confirmed by the X-ray diffraction patterns and the other properties were also improved. In view of the fundamentals of major pharmacopeias for use of bentonite in pharmacy and considering the chemical composition, microbiological results we could designate a pharmaceutical acceptable denomination for Pakistani purified bentonite samples. The two purified samples vary in interlayer cations, chemical composition and other properties that would present different behavior in pharmacy. The studied bentonite in purified form could be used as suspending and disintegrating agent because of its excellent swelling capacity and sedimentation volume. The high cation exchange capacity, high surface area and pore size distribution suggest their use as a good adsorbent of drugs and a drug carrier in controlled drug release system.

Potential use of calcareous mudstones in low hydraulic conductivity earthen barriers for environmental applications

Earthen layers play a significant role in isolating contaminants in the subsurface, controlling the migration of contaminant plumes, and as landfill liners and covers. The physical, chemical and mineralogical properties of three calcareous mudstones from the Jagüel and Roca formations in North Patagonia, Argentina, are evaluated to determine their potential for the construction of liners. These mudstones were deposited in a marine environment in the Upper Cretaceous–Paleocene. The tested specimens mainly comprise silt and clay-sized particles, and their mineralogy is dominated by a smectite/illite mixed layer (70–90% Sm) and calcite in smaller proportion. Powdered mudstone samples have little viscosity and swelling potential when suspended in water. The hydraulic conductivity of compacted mudstones and sand–mudstone mixtures is very low (around 1–3×10−10 m/s) and in good agreement with the expected hydraulic behaviour of compacted earthen layers. This behaviour can be attributed to the large amount of fine particles, high specific surface and the close packing of particles as confirmed by scanning electron microscope analysis. The tested materials also show a high cation exchange capacity (50–70 cmol/kg), indicating a high contaminant retardation capability. The calcareous mudstones show satisfactory mineralogical and chemical properties as well as an adequate hydraulic behaviour, demonstrating the potential use of these materials for the construction of compacted liners for the containment of leachate or as covers in landfills. These findings confirm the potential usage of marine calcareous mudstones as a low-cost geomaterial in environmental engineering projects.

Hydrothermal Synthesis of Zeolites from Lake Sludge

Sludge tends to accumulate easily in lake due to the closed water system and the pollutants contained inside could cause serious environmental problems. The sludge accumulation is mainly solved by dredging the lake, although the general disposal method of the dredged sludge by landfilling remains a problem due to formation of soft-ground and limited space. In this study, the conversion of the dredged sludge into adsorbent material that can be used for water treatment was tried. Using hydrothermal treatment in alkali medium, lake sludge which main components are silica and alumina could be converted into zeolite. The effects of various treatment conditions (NaOH concentration, alkali solution volume to dry sludge weight L/S ratio, Si/Al molar ratio, reaction temperature) were investigated. The adsorption abilities of synthesized zeolites were evaluated by measuring the cation exchange capacity (CEC) value and adsorption capacity towards heavy metals in aqueous solution (Pb, Cd). Soluble elements in sludge such as silica and alumina tend to dissolve at higher temperature and form zeolite. Zeolite type Na-P1 which was synthesized at silica/alumina (Si/Al) ratio of 2.5 and reaction temperature of 120°C showed the highest CEC value. The synthesized zeolites showed some adsorption ability towards heavy metals in aqueous solution (Pb2+ (Xm=55.3mg/g) and Cd2+ (Xm=40.9mg/g)).

Distribution of Soil Fertility of Smallholding Arabica Coffee Farms at Ijen-Raung Highland Areas Based on Altitude and Shade Trees

Soil fertility is one of the most important factors influencing plant growth and productivity and it depends on the availability and quantity of nutrients in the soil. To study soil fertility status of an area, a study on soil chemistry and physics has to be conducted. The aim of this study was to investigate soil fertility status of smallholding Arabica coffee farms based on altitude and shades trees utilization. This research was carried out in April-August 2012 at IjenRaung highland areas by field survey. The results showed that the soil contained high content of organic carbon, nitrogen total, and C/N ratio; low available phosphorus; moderate to high cation exchange capacity, and low base cation of calcium, magnesium, and potassium; as well as slightly low pH. Higher altitude tended to have higher C organic and N total content, C/N ratio as well as pH. In contrast, in lower altitude tended to have lower available P, base saturation, as well as Ca, Mg, and K content. The dominant shade trees for coffee farming at the Ijen-Raung highland areas were suren (Toona sureni) , dadap (Erythrina sp.), kayumanis (Cinnamomum zeylanicum), pinus (Pinus mercusii), and kayu putih (Eucalyptus globulus). Different shade tree species resulted in different of soil fertility. Shade trees tended to influence cation exchange capacity from moderate to high, pH slightly acid, high base saturation, and low P available. Suren tree influenced better base cation than that of other trees but dadap tree was better in increasing soil fertility. Key word: Soil fertility, arabica coffee, andisol, shade trees, smallholding

The promise [and uncertainties] of Biochar

The promise [and uncertainties] of Biochar

Preparation of zeolitic material with simultaneous removal of NH4 + and PO4 3− from paper sludge ash via acid leaching

This study investigates the preparation of zeolitic material with removal of both NH4+ and PO43− from paper sludge ash (PSA) via acid leaching. PSA typically has a low Si and high Ca content, owing to the presence of calcite fillers. Acid leaching with 3 M HCl was used firstly to reduce the Ca content of the PSA, whereafter a zeolite-P (Na-P) product with high cation exchange capacity (CEC) was synthesized through reaction with 2.5 M NaOH solution at 80 °C. Ca-P zeolitic products were prepared by Ca-treatment with the leachant that had been in contact with the PSA. The product with high CEC capacity including Na-P could be synthesized from the acid-leached ash, and the high Ca content in the ash could be reduced by extraction of the Ca into the leachant via the acid leaching. The Ca-P zeolitic product could be prepared by Ca-treatment with the solution obtained from neutralization of the leachant with NaOH. This product was capable of removing NH4+ and PO43− from aqueous solution, simultaneously.

Opposite response of phosphorus sorption to pH and ionic strength: a comparative study in two different shallow lake sediments

Phosphorus (P) sediment sorption is regarded as the most important buffering process against P increases in overlying water. In this study, two shallow eutrophic sediments (Mei and Hua) with distinct compositions were selected to assess effects of pH (from 6 to 9) and ionic strength (IS) (0, 0.001, 0.01 and 0.1 M KCl) on P sorption. In Mei sediments, the P sorption decreased as pH increased (6.97–9.13), but it increased as IS increased over the pH range in question. These results could be attributed to the negatively charged surface of Mei sediments, as indicated by the salt titration curve, and the high cation exchange capacity (CEC). P sorption in Hua sediments was facilitated by a pH increase (6.12–7.49), but it was hindered by an IS increase. A reasonable explanation for this phenomenon is that calcium phosphate precipitates at high pHs and that Cl− exchanges with P because the surface is weakly charged (small CEC). These results indicate that the sediment P sorption may have trends opposite to one another in relation to the salt change (e.g. drought and rainy season) in the lake water between the two sediments. These data provide additional support to explain P concentration variations in lakes.

Mineralogical Composition Of Soils From Urir Char ? A Tiny Offshore Island Of Bangladesh

Mineralogical composition of three surface soils from Urir Char ? an environmentally vulnerable small offshore island of Bangladesh ? was determined by X-ray diffraction analysis. In the bulk soils layer silicates and quartz were the dominant minerals while the quantity of feldspars was around ten percent. Quantity of weatherable minerals was very high in the soils. Illite was the dominant mineral in the clay fraction of the soils. The second dominant clay mineral was smectite which comprised around one-fourth of the clay fraction closely followed by chlorite with a small quantity of kaolinite mineral. Soil vermiculite and mixed layer minerals were absent in these soils. These soils had a mixed mineralogical composition with a high cation exchange capacity and percent base saturation. Texturally the soils were silty loam. Exchangeable Ca++/ Mg++ ratio was less than unity. Magnesium solonization was considered as the dominant pedogenic process along with gleization. There was problem of salinity as the elevation of land was around one meter above the mean sea level. Natural calamities like tropical cyclones and tidal surges were highly devastating as the island was completely washed with sea water. J. Asiat. Soc. Bangladesh, Sci. 39(1): 95-104, June 2013 DOI: http://dx.doi.org/10.3329/jasbs.v39i1.16038

The removal of cesium ion with natural Itaya zeolite and the ion exchange characteristics

AbstractBACKGROUNDThe large Itaya zeolite deposit in Yonezawa, Japan produces good quality, natural zeolite. Its properties as an adsorbent and a functional carrier were assessed and the ion exchange characteristics examined. Natural zeolite has a useful high cation exchange capacity, but has a disadvantage in scattering of the powder. In this study a nonwoven fabric containing zeolite was tested for the removal of cesium.RESULTSThe X‐ray diffraction (XRD) peak pattern confirmed that Itaya zeolite is mainly clinoptilolite and contains some mordenite. Ion exchange selectivity of the natural zeolite was Ag+ > Pb2+ > Cu2+ > Zn2+ > Cd2+ > Cr3+ > Ni2+ with almost 100% removal of Ag+ and Pb2+ ions.The cation exchange capacity (CEC) of Itaya zeolite was 131 cmol kg‐1. Low concentrations of Cs+ were removed effectively from the solution with natural zeolite. Cesium ions were removed by ion exchange with potassium and sodium. Cs+ was desorbed from the zeolite with ammonium salt solutions. Elution of Cs+ was influenced by the coordination ability of counter anions.CONCLUSIONSatisfactory results were obtained using zeolite‐containing nonwoven fabric for the removal of cesium ions. © 2013 Society of Chemical Industry

Sulfonated hypercrosslinked adsorbent – synthesis and application in analytical chemistry

Chromatographic technique becomes more and more popular in analytical chemistry thanks to the diversity of stationary phases. Among the materials hypercrosslinked poly(styrene-co-divinylbenzene-co-vinylbenzyl chloride) is of great interest because of its exceptional high surface area and chemical resistance. Despite the advantages the polymer, its applications are still limited. Its surface is too hydrophobic for hydrophilic analytes therefore several reactions have been used to modify this material. The most popular reaction is sulfonation in which sulfonate group is introduced on to the material surface. In this study chlorosulfonic acid was used as sulfonation reagent, the resulting polymer has two functional groups: sulfonate and sulfonyl chloride. Then sulfonyl chloride group was hydrolyzed by sodium hydroxide to form sulfonate group. The reaction conditions namely ratios of reagent to polymer and reaction time were investigated for high cation exchange capacity. The home-made sulfonated material was sucessfully used as solid phase extraction (SPE) sorbent with high static capacity (10 meqv/g), dynamic capacity (3.8 meqv/g), fast mass transfer, and high enrichment factor.

Heavy-metal uptake by a high cation-exchange-capacity montmorillonite: the role of permanent charge sites

A High Cation Exchange Capacity (HCM) montmorillonite clay has been prepared by acetate treatment of Zenith clay. The HCM has been evaluated for metal-uptake from aqueous solutions. The present data show that the cation exchange sites can play a significant role in the adsorption of metals in smectite clays. A theoretical analysis scheme has been developed which shows that permanent-charge sites can become dominant in metal-uptake by clays. In addition, it was shown that the permanent charge can influence the ionic-strength sensitivity of the Point of Zero Charge of the clay.

Use of drinking water sludge in the production process of zeolites

This study reports the synthesis of zeolites A, X, and P, cancrinite, and sodalite using sludge generated in a drinking water plant. Two experimental steps were carried out: (1) fusion and (2) hydrothermal treatment. Crystallization was achieved by means of a 2 3 experimental design with central point with the following factors: temperature, time, and solid/liquid ratio. The sludge presented Si and Al contents (SiO2/Al2O3 = 1.7) which allow the synthesis of zeolites with high cation exchange capacity. The content of organic matter was considerable (loss on ignition 26.1 %), but is eliminated in the fusion step at 550 C. This process also permits the conversion of the initial aluminosilicates into zeolite precursors (sludge-NaOH mix of 1:0.785 g/g). Hydrothermal treatment then permits the crystallization of the aforementioned zeolites. These materials showed high cation exchange capacities as compared to other commercial and experimentally synthesized zeolites, and can be used in the removal of heavy metals such Cd 2? ,P b 2? ,C u 2? ,F e 2? , and ammonium present in water, providing an interesting new option in wastewater treatment and remediation of soils.

Characteristics, modification and environmental application of Yemen’s natural bentonite

The bentonite deposit of Lahij Province, Yemen, has very promising commercial applications due to its mineralogy and physical and chemical properties. It was examined to determine its mineralogical composition, chemical and physical properties of the bentonite deposit, purity and sodium-exchanged bentonite. Modified bentonite was synthesized by exchanging cetyltrimethylammonium cations for inorganic ions on the bentonite and its adsorption properties for ammonium were characterized in batch experiments. Analytical methods were carried out to study the bentonite comprising X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy, chemical analysis and kinetic and isotherm models were also tested. The results have shown that the purification of bentonite resulted in a bentonite fractions of the total sample composed of montmorillonite and <5 % quartz. The XRD data showed that the interlayer spacing (d 001) of bentonite decreased from 15.3 to 12.5 A and then increased to 19.7 A. Moreover, high cation exchange capacity, good water absorption and high swelling capacity were also obtained. The results have shown that the modified bentonite was more effective than the natural bentonite for ammonium removal. In addition to that, pseudo-second-order kinetic model, Freundlich and the Langmuir models described the adsorption kinetics and isotherm well. It was concluded that Yemen (Alaslef) bentonite can be potential adsorbents for ammonium removal.

Adsorption Characteristics of Zinc (Zn&amp;lt;sup&amp;gt;2+&amp;lt;/sup&amp;gt;) from Aqueous Solution by Natural Bentonite and Kaolin Clay Minerals: A Comparative Study

Clay minerals are one of the potential good adsorbent alternatives to activated carbon because of their large surface area and high cation exchange capacity. In this work the adsorptive properties of natural bentonite and kaolin clay minerals in the removal of zinc (Zn2+) from aqueous solution have been studied by laboratory batch adsorption kinetic and equi- librium experiments. The result shows that the amount of adsorption of zinc metal ion increases with initial metal ion concentration, contact time, but decreases with the amount of adsorbent and temperature of the system for both the ad- sorbents. Kinetic experiments clearly indicate that adsorption of zinc metal ion (Zn2+) on bentonite and kaolin is a two-step process: a very rapid adsorption of zinc metal ion to the external surface is followed by possible slow decreas- ing intraparticle diffusion in the interior of the adsorbent. This has also been confirmed by an intraparticle diffusion model. The equilibrium adsorption results are fitted better with the Langmuir isotherm compared to the Freundlich model. The value of separation factor, RL from Langmuir equation give an indication of favourable adsorption. Finally from thermodynamic studies, it has been found that the adsorption process is exothermic due to negative ?H0 accompa- nied by decrease in entropy change and Gibbs free energy change (?G0). Overall bentonite is a better adsorbent than kaolin in the the removal of Zn2+ from its aqueous solution.

Ion Exchange Properties of Japanese Natural Zeolites in Seawater

Ion exchange properties of five different Japanese natural zeolites in seawater were examined. Sodium ions could be reduced by all zeolites, although anions, Cl(-) and SO(4)(2-), in seawater showed barely changes. Natural zeolite desalination treatment mainly depends on the ion exchange between Na(+), K(+) and Mg(2+) in seawater and Ca(2+) in natural zeolite. This study found that mordenite is superior to clinoptilolite for use in Na(+) reduction. Mordenite with high cation exchange capacity containing Ca(2+) resulted in the highest Na(+) reduction from seawater.

Efeito da adição de zeólita e vermiculita na lixiviação de potássio do solo

Este trabalho teve o objetivo de estudar a lixiviação do potássio (K+) adicionado em um solo (Latossolo Vermelho) e avaliar a eficiência de retenção desse íon com a adição de minerais com elevada capacidade de troca catiônica (CTC), como vermiculita e zeólita. Amostras de Latossolo Vermelho coletadas em Araraquara (SP) foram caracterizadas física, química e mineralogicamente. O solo possui textura argilosa, baixa acidez e é pobre em nutrientes e em minerais fontes de K+. A lixiviação de potássio nesse solo foi avaliada a partir de dois testes: (1) lixiviação de K+ em colunas preenchidas com solos, na presença de vermiculita ou zeólita e (2) incubação de solos com vermiculita e zeólita durante 30 dias para verificar a interação desses minerais com o K+ adicionado ao meio, na presença/ausência de Ca2+ (na forma de CaCO3). Os testes de lixiviação em colunas revelaram que a textura e a mineralogia do solo desempenham importante papel na retenção de K+, promovendo a rápida transferência de sua fase solúvel para a fase trocável. O latossolo perdeu, em média, somente 2% do total de K+ adicionado ao sistema e esse valor decresce para 1,6% na presença de vermiculita e 1,2% com zeólita. Nos testes de incubação também se observou que o K+ solúvel introduzido no meio é logo transferido para a fase trocável e a introdução de vermiculita e zeólita aumenta a taxa de sua retenção no solo. A presença de cálcio no meio, no entanto, não favorece a retenção de K+ pela vermiculita - que prefere reter cátions de maior valência como o Ca2+. O mesmo não acontece com a zeólita, cujos sítios de troca preferem cátions de menor valência como o K+. De forma geral, verificou-se que a adição de minerais com elevada CTC aumenta a disponibilidade de K+ na fase fixa, que pode servir de reserva desse íon, e ainda diminui a perda por lixiviação desse nutriente no solo.

The reaction between Nafion sulfonyl fluoride precursor membrane and 1,4-dimethylpiperazine does not yield reliable anion-exchange membranes

Recent reports that the reaction between Nafion sulfonyl fluoride precursor and the cyclic diamine 1,4-dimethylpiperazine yields stable anion-exchange membranes appear to be premature. On aqueous work up, membranes with high cation-exchange capacities and zero anion-exchange capacities are produced.