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1

Adsorption of hydrated Fe(OH)2+ on the kaolinite surface : A density functional theory study

Wu Hongqiang, Miao Yuqi, Long Qibang, Yan Huashan, Li Yong, Qiu Sen, Wu Hao, Zhao Guanfei, Qiu Tingsheng

Physicochemical Problems of Mineral Processing

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2023

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Vol. 59, iss. 6

art. no. 174415

EN

The present study employed density functional theory (DFT) to analyze the adsorption configuration and mechanism of Fe(OH)2+ on the kaolinite (001) surface. The findings demonstrated that Fe(OH)2(H2O)4+ is the main type in which hydrated Fe(OH)2+ can be found in aqueous solution. On the surface of kaolinite, Fe(OH)2(H2O)4+ will be adsorbed. There are two forms of adsorption: outer-sphere and inner-sphere coordination (monodentate/bidentate) adsorption. Fe(OH)2(H2O)4+ has a moderate propensity to adsorb on the alumina octahedral sheet of kaolinite when the outer-sphere coordination adsorption takes place. In cases of inner-sphere coordination adsorption, Fe exhibits a tendency to form monodentate adsorption compounds in conjunction with Ou atoms. Additionally, it prefers to create bidentate adsorption compounds through coordination with both Ot and Ou atoms. The adsorption mechanism analysis results show that the ionic property of Fe atom decreases after outer-sphere coordination adsorption. After inner-sphere coordination adsorption, some electrons of Fe atom are transferred to the surface O atom. The presence of electrons between the Fe and O atoms enhances the formation of bonds, hence enhancing the covalent nature of the Fe-O bond. Theoretical FT-IR (Fourier transform infrared spectroscopy) calculations show that the formation of Fe-O chemical bonds. Because of the lower adsorption energy and more chemical bonds, hydrate Fe(OH)2+ is more likely to be bidentate adsorbed on the kaolinite surface.

2

An Innovative Interaction between Organo-Kaolinite and Methyl Orange for Industrial Wastes Removal – A Kinetic Investigation and Modeling

Al-Zubaidi Hussein A. M., Al-Khalaf Safaa K. Hashim, Naje Ahmed Samir

Ecological Engineering & Environmental Technology

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2023

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Vol. 24, iss. 8

329--345

EN

Since organic dyes are the main component of many industrial wastes, it is necessary to be removed efficiently and instantaneously. The aim of this research focuses on the synthesizing of organoclay by modifying kaolinite with cetyl trimethyl ammonium bromide and applying it for the removal of (methyl-orange) dye from water by the mechanisms of adsorption. The effects of several parameters, mainly agitation time, water pH, adsorbent doses, and dye concentrations, on the adsorption process were optimised using the central composite design (CCD) method, which was performed using MINITAB package (version 17). Results showed that the dye was completely (100%) removed at pH of 4.0, adsorbent dose of 0.4 g, dye concentration of 50 mg/L, and agitation speed of 160 rpm. In addition, it was found that Freundlich and Sips isotherms were the best models to track lab data. Moreover, the Pseudo second order method was found to be more convenient compared to other models for studying kinetics of the sorption mechanism. For column testing, an appropriate hydraulic conductivity and reactivity were obtained by combining modificatory kaolinite and glass waste with weight proportions of 50:50. Thus, empirical simulations such as those in the kinetic model of Clark have provided satisfactory consent for using the simulated methyl orange.

3

Characterization of the Structural and Physical Properties of the Thermoplastic Starch Film with Kaolinite and Beeswax Addition

Beer-Lech Karolina, Skic Anna, Skic Kamil, Stropek Zbigniew

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 5

312--323

EN

The aim of the study was to investigate the influence of kaolinite (KA) and beeswax (BW) addition on the structural and physical properties of thermoplastic starch (TPS) films. The casting method was applied and glycerol was used as a plasticizer. Microstructure analyzes were made by a stereoscopic and a scanning electron microscope. Tensile tests were carried out under static load conditions at three different deformation velocities of V=0.0001, 0.001, and 0.01 m/s. The studies of surfaces characteristic were performed using water contact angle and water vapor isotherm measurements. The most homogeneous structure of the surface with higher mean values of failure stress and elasticity modulus was observed for thermoplastic starch films with kaolinite addition. The significant reduction in dynamics changes of water contact angle (10%) of BW films in the time 0-20s as well as tensile strength decrease was noted (compared to pure TPS films). The research results suggest the validity of using BW and KA to improve the barrier and mechanical properties of TPS films. Further research should focus on to improve the starch-beeswax-kaolinite combination and increase the homogeneity of the structure of films in order to upswing their simultaneous impact on barrier and mechanical properties.

4

Wstępna charakterystyka mineralogiczna czarnych łupków antrakozjowych z obszaru synklinorium śródsudeckiego

Wójcik-Tabol Patrycja, Dąbek Jolanta, Nowak Grzegorz J.

Przegląd Geologiczny

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2021

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Vol. 69, nr 6

389--392

EN

Anthracosia Shales within the Pennsylvanian-Lower Permian continental succession from the Intra-Sudetic Synclinorium are lacustrine sediments, represented by black shales intercalated with sandstones/mudstones. Mineral composition of each lithology consists of quartz, feldspar, mica, clay minerals (including kaolinite, the content of which decreases upward the section), and carbonates (calcite and siderite). The section is a continuous record of reduction and rise in terrigenous input. Mineral detritus is least weathered in the uppermost part of the Anthracosia Shales. The sedimentation occurred under dysoxic conditions that were ventilated by bottom currents.

5

Wpływ dodatków paliwowych na emisję tlenków azotu przy spalaniu biomasy agrarnej

Sobieraj Jakub, Kalisz Sylwester

Instal

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2021

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nr 3

22--25

PL

Praca przedstawia analizę wpływu dodatków paliwowych na emisję tlenków azotu z procesu spalania biomasy w laboratoryjnym piecu rurowym. Analiza wykonana została dla dwóch udziałów masowych, dwóch glinokrzemianów z grupy kaolinitu – kaolinu oraz haloizytu. Oba glinokrzemiany są przedmiotem badań naukowców z Politechniki Śląskiej jako substancje wpływające pozytywnie na proces spalania, tj. zmniejszające zanieczyszczanie powierzchni ogrzewalnych kotła, a także poprawiające jakość UPS – Ubocznych Produktów Spalania, do których zaliczany jest popiół lotny. Ten ostatni fakt jest o tyle istotny, że w obecnej sytuacji, w której obszarem priorytetowym staje się Gospodarka Obiegu Zamkniętego, popioły stanowią potencjalne źródło surowca, który jeszcze niedawno uznawany był za odpad, a spektrum jego ponownego wykorzystania było dość wąskie. Analiza ta ma na celu laboratoryjne sprawdzenie wpływu zastosowania addytywów na emisję NOx przy spalaniu biomasy i wynika z niejednoznacznych obserwacji dokonanych podczas badań wpływu addytywów na inne własności procesu spalania. Zaobserwowano wówczas, że jedynym negatywnym wpływem zastosowania glinokrzemianów jest nieznaczne zwiększenie emisji NOx. Niniejsza praca uściśla te obserwacje.

EN

This paper presents an analysis of the effect of fuel additives on nitrogen oxide emissions from biomass combustion in a laboratory tube furnace. The analysis was performed for two mass fractions, i.e. two aluminosilicate minerals from kaolinite group – kaolin and halloysite. Both aluminosilicates are the subject of research carried out by scientists from the Silesian University of Technology as substances that have a positive effect on the combustion process, i.e. reduce the fouling effect in the boiler heating surfaces and improve the quality of combustion by-products of, which include fly ash. It is very important because while the Circular Economy is becoming a priority area, ash is a potential source of raw material that until recently was considered as waste and the spectrum of its reuse was quite narrow. This analysis is intended as a laboratory test of the effect of the use of additives on NOx emissions from biomass combustion and stems from the inconclusive observations made when studying the effect of additives on other properties of the combustion process. It was observed then that the only negative effect of using aluminosilicates was a slight increase in NOx emissions. The present work clarifies these observations.

6

Adsorption of methylamine cations on kaolinite basal surfaces : A DFT study

Chen Jun, Min Fan-fei, Liu Ling-yun, Jia Fei-fei

Physicochemical Problems of Mineral Processing

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2020

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Vol. 56, iss. 2

338--349

EN

To explore the interaction of alkylamine surfactants with kaolinite, the density functional theory (DFT) method was used to calculate the single adsorption of different methylamine cation on kaolinite basal surfaces and the competitive adsorption of methylamine cation and water molecule on kaolinite basal surfaces, respectively. Different methylamine cations can adsorb on kaolinite basal surfaces by electrostatic interaction and hydrogen bonds, and the methylamine cations more easily adsorbed on kaolinite Si-O surface. In the case of competitive adsorption with water molecule, the methylamine cation is capable of flushing out the surrounding water molecule to get rid of its steric effect and stably adsorbing on kaolinite basal surfaces, and the adsorption state of the competitive adsorption system is more stable. The adsorption mechanism of methylamine cation on kaolinite basal surface should be the result of electrostatic interaction and hydrogen bonds, and the electrostatic interaction plays the main role.

7

The structure of electrical double layer formed on the kaolinite surface in the mixed system of cationic polyacrylamide and lead (II) ions

Fijałkowska Gracja, Wiśniewska Małgorzata, Szewczuk-Karpisz Katarzyna

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 6

1339--1349

EN

The bioavailability of toxic heavy metalsfor organisms depends mainly on the soil physicochemical properties, i.e. type and granulometric composition, pH value, redox potential, individual fractions content and microorganisms presence. The addition of artificial fertilizers rich in humic substances or polyacrylamide soil flocculants may also affect the content of easily absorbed heavy metal forms. Due to their chelating properties, the added substances can bind metal ions in the form of complexes characterized by low mobility in soil environment. As a consequence, the immobilization process takes place, which is a desirable phenomenon for organism health.The aim of the study was to determine the structure of electrical double layer formed on the kaolinite surface in the mixed system of cationic polyacrylamide and lead(II) cations. The influence of cationic PAM presence on the Pb(II) ions sorption on the kaolinite surface as well as heavy metal ion addition on the polymer adsorbed amount on the same clay mineral were studied. The adsorption and electrokinetic properties of studied kaolinite/CT PAM/Pb(II) systems were determined based on the spectrophotometric study, zeta potential measurements as well as potentiometric titration.

8

Adsorption of lanthanum(III) and yttrium(III) on kaolinite: kinetics and adsorption isotherms

Zhou Fang, Feng Jian, Xie Xiong, Wu Baihong, Liu Qi, Wu Xiaoyan, Chi Ruan

Physicochemical Problems of Mineral Processing

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2019

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Vol. 55, iss. 4

928--939

EN

Experimental investigations were carried out using kaolinite to adsorb two rare earth ions, lanthanum ion (La3+) and yttrium ion (Y3+), which will provide some useful information and new insights on the mineralization process and fractionation phenomenon of weathered crust elution-deposited rare earth ores. The results showed that the equilibrium adsorption capacity of Y3+ is greater than La3+ under the same experimental conditions. The adsorption of rare earth ions presents strongly temperature dependent indicating an endothermic adsorption process. The pseudo-first-order kinetic model and the pseudo-second-order kinetic model were applied to discuss the adsorption kinetics. It was found that the adsorption rate of rare earth follows the pseudo-second-order kinetic model among the adsorption temperature range. Furthermore, the adsorption process of rare earth ions on kaolinite followed the Langmuir isotherm model confirmed by the correlation of experimental equilibrium data to standard isotherm model, Langmuir and Freundlich isotherms. The activation energies for the adsorption of La3+ and Y3+ on kaolinite are 28.1903 kJ/mol and 25.4190 kJ/mol, respectively. All kaolinite before and after adsorption were characterized by XRD and SEM-EDX to understand the adsorption mechanism. The obtained results suggested that the adsorption of La3+ and Y3+ on kaolinite is an endothermic and chemisorption process.

9

Solid-State Mechanochemical Synthesis of Kaolinite-Urea Complexes for Application as Slow Release Fertilizer

AlShamaileh Ehab M., Al-Rawajfeh Aiman E., Alrbaihat Mohammad R.

Journal of Ecological Engineering

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2019

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Vol. 20, nr 9

267--276

EN

This study investigated a mechanochemical (MC) process for synthesizing a slow-release urea fertilizer by cogrinding the starting materials of (NH2)2CO and amorphous kaolinite in a planetary ball mill. The tests with kaolinite contents ranging from 25 to 75 wt. %, milling time ranging from 1 (h) to 3 (h) and mill rotational speeds from 200 to 700 rpm were performed to evaluate the incorporation of (NH2)2CO and release of nitrogen into the solution. The analyses conducted using XRD, TGA, FT-IR and KNDU (Kjeldahl Nitrogen Determination Unit) indicated that the MC process was successfully applied to incorporate (NH2)2CO into the amorphous kaolinite structure. The release of nitrogen from the system (kaolinite-(NH2)2CO) when dispersed in water for 24 h reached up to 20% at 25% wt of kaolinite. Moreover, under the milling speed conditions for the system (kaolinite–(NH2)2CO), release of nitrogen reached between 25 and 40%. These results indicated that the MC process can be developed to allow amorphous kaolinite to act as a carrier of nitrogen nutrients to be released slowly for use as fertilizer.

10

Mineralogical, geochemical and stable isotope studies of kaolin deposits in north-west Gonabad district (eastern Iran)

Zirjanizadeh S., Rocha F., Samiee S.

Geological Quarterly

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2018

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Vol. 62, No. 2

385--399

EN

Kaolin deposits, situated ~10 km north-west of Gonabad (eastern Iran), formed by the intrusion of hydrothermal fluids from a granite dyke in the western part of the study area, and the alteration of rhyolite, dacite and rhyodacite related to Eocene volcanism. There are four major kaolin quarries. The rocks in the investigated area are mainly slate, dacite, rhyolite, andesite-trachyandesite, and lithic and felsic tuffs. The mineralogical compositions of the kaolin deposits are dominated by quartz, kaolinite, dickite and illite with minor chlorite, montmorillonite, albite, hematite, pyrite and gypsum. Sanidine and plagioclase crystals in rhyolite-rhyodacite are sericitized and kaolinized. Whole rock chemistry of the kaolin deposits shows high contents of SiO2 and Al2O3. Enrichments of Sr in some samples demonstrate retention of Sr and depletion of Rb, Ba, Ca and K during hydrothermal alteration of sanidine and plagioclase within the volcanic units. The chondrite-normalized rare earth element patterns of the clay deposits show LREE enrichments (La/Lu)cn = 6.75 to 57.74, pointing to kaolinization in low-pH waters. The isotope composition of the kaolin (δ18O ~+5‰) is consistent with formation at isotopic equilibrium with water of hydrothermal/magmatic origin. The mineralogical composition, REE contents and elemental ratios in these deposits suggest provenance of the kaolin deposits mainly from felsic rocks and hydrothermal fluids. The O isotopic character also supports these results.

11

Role of calcium and magnesium cations in the interactions between kaolinite and chalcopyrite in seawater

Uribe L., Gutierrez L., Laskowski J. S., Castro S.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

737--749

EN

A number of flotation plants around the world have increased the use of seawater due to limited sources of fresh water. The aim of this research work is to study the role that Mg2+ and Ca2+ ions play in the interactions between kaolinite and chalcopyrite in seawater. In order to achieve this objective, the effect of kaolinite on flotation of chalcopyrite is studied over the pH range from 8 to 11, when flotation is carried out in seawater and in a 0.01M NaCl solution. The influence of calcium, magnesium, sodium, and potassium ions on the extent of depression by kaolinite is evaluated. The micro-flotation results indicate that chalcopyrite is depressed by kaolinite in both 0.01 NaCl solution and seawater. In the 0.01 NaCl solution, the depressing effect of kaolinite decreases as the pH increases from 8 to 11. However, the results obtained using seawater show that the depressing effect of kaolinite is similar to what is observed in a 0.01 NaCl solution only at pH values below 9, but above this pH kaolinite significantly affects the recovery of chalcopyrite. The results from experiments with using solutions containing individual cations show that the depressing action of kaolinite in the presence of Mg2+ and Ca2+ is more obvious at pH values of 9 and 10, respectively, which correlates with the pH values at which the first hydroxy-complexes of these divalent cations start forming. This seems to indicate that depressing effect of kaolinite on chalcopyrite in seawater may be related to formation of hydrolyzed species of calcium and magnesium. These species can induce heterocoagulation between kaolinite and chalcopyrite. The trends observed in the micro-flotation experiments are in good agreement with the results of the induction time measurements and slime coating tests.

12

Efficiency of Pb(II) and Mo(VI) removal by kaolinite impregnated with zero-valent iron particles

Rybka K., Suwała K., Maziarz P., Matusik J.

Mineralogia

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2017

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Vol. 48, iss. 1/4

71--86

EN

In this work, kaolinite modified with zero-valent iron was synthesized and used as a sorbent for Pb(II) and Mo(VI) removal from aqueous solutions. The obtained material was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) spectroscopy. The methods revealed successful modification by the Fe0 particles precipitation on the surface of well-ordered kaolinite. The sorption experiment results showed a significant increase of sorption capacity in relation to the raw kaolinite. The kaolinite with 25% content of Fe0 was found to be the best material for Pb(II) and Mo(VI) removal, resulting in approximately 500 mmol•kg-1 and 350 mmol•kg-1 sorption, respectively. The possible mechanisms responsible for metals’ removal were identified as reduction by Fe0 ‘core’ and adsorption on the iron hydroxides ‘shell’. The study indicated that the obtained material is capable of efficient Pb(II) and Mo(VI) removal and may be an interesting alternative to other methods used for heavy metals’ removal.

13

Selective adsorption of anionic polyacrylamide onto ultra-low ash coal and kaolinite

Zou W., Yu C., Sun C., Cao Y.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

738--753

EN

To study the selectivity of polyacrylamide in the selective floc flotation of fine coal, adsorption of anionic polyacrylamide (PAM A401) onto ultra-low ash coal and kaolinite was studied, including the adsorption thermodynamics, floc size distribution and wettability changes. The thermodynamics of the adsorption process at the low concentration of 0-16 mg/dm3 of PAM A401 were studied at different contact times, doses, temperatures and pH values. Thermodynamic parameters of ΔGo, ΔHo, ΔSo and Ea were evaluated to understand the nature of the adsorption process. The results indicated that PAM A401 was selectively adsorbed onto ultra-low ash coal rather than kaolinite. Physical adsorption was the predominant mechanism, and the adsorption of PAM A401 at 12 mg•dm-3 onto coal was 2.15-fold larger than the adsorption on kaolinite. After the adsorption of PAM A401, the lipophilic hydrophilic ratio (LHR) of coal decreased from 9.23 to 7.28, indicating that the coal became less hydrophobic than before. In contrast, the LHR of kaolinite increased from 1.44 to 1.65. Floc size measurements showed that the d10, d50 and d90 of coal flocculated by PAM A401 (at 12 mg/dm3, pH 6.5) were 3.18, 2.76 and 2.59-fold greater than the corresponding levels of these parameters for kaolinite flocs, respectively.

14

Identyfikacja składu mineralnego i pęcznienia gruntów spoistych na podstawie współczynnika swobodnego pęcznienia

Izdebska-Mucha D., Wójcik E.

Biuletyn Państwowego Instytutu Geologicznego

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2016

|

nr 466

77--85

EN

The paper presents the results of free swell measurements of Neogene clays and model clay mixtures composed of Wyoming bentonite and Sedlec kaolinite. Modified free swell index (MFSI) as well as free swell ratio (FSR) were determined and analyzed with respect to pore fluid chemistry, mineral composition and clay content. The FSR, defined as the ratio of the equilibrium sediment volume of 10-g oven dried soil in 0.0025% NaCl solution to that in kerosene, has proved to provide only a rough prediction of clay mineralogy in natural soils.

15

Wpływ minerałów ilastych na właściwości zaczynu cementowego z dodatkiem naftaleno-sulfonianu sodowego

Tan H., Lin C., Yang H., Ma B., Qi C., Li X.

Cement Wapno Beton

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2015

|

R. 20/82, nr 3

193--200

PL

W pracy zbadano wpływ dodatku minerałów ilastych do cementu, a mianowicie kaolinitu i montmorillonitu na właściwości zaczynu z równoczesnym dodatkiem superplastyfikatora naftalenowego. Przeprowadzone doświadczenia wykazały, że adsorpcja plastyfikatora przez kaolinit i montmorillonit, badane za pomocą spektrometru promieniowania ultrafioletowego, była mniejsza niż cementu. Jednak szereg właściwości zaczynu uległo pogorszeniu, a szczególnie skurcz suszenia zaczynu cementowego zwiększył się, a wytrzymałość na ściskanie uległa zmniejszeniu. Wodożądność wzrosła bardzo znacznie, a konsystencja zaczynu uległa pogorszeniu. W podsumowaniu można stwierdzić, że należy unikać występowania w betonie minerałów ilastych, gdyż mają one niekorzystny wpływ na właściwości tego kompozytu.

EN

In the paper the investigations of the effect of clay minerals addition, namely kaolinite and montmorillonite, to cement on the properties of cement paste with sodium naphthalene sulfonate superplasticizer(NS) are presented. The studies have shown that the adsorption of NS by kaolinite and montmorillonite, determined by UV-VIS spectrophotometer, was lower than that of cement, but several cement paste properties were worse. Particularly the drying shrinkage of cement paste was increasing and the compressive strength was much lower as well as water demand was drastically increased and consistency of the paste was decreased. Summarizing the presence of clay minerals should be avoided in concrete because they have very disadvantage effect on the properties of this composite.

16

Competitive sorption of selected anions on modified halloysite

Prokop A., Matusik J.

Geology, Geophysics and Environment

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2014

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Vol. 40, no. 1

118--119

EN

Halloysite is a polytype of kaolinite exhibiting a 1:1 layered structure with the chemical composition of Al4Si4O10(OH)8. Synthesis of new materials based on kaolinites has received wide attention recently (e.g. Dedzo et al. 2012). Soluble forms of chromium, arsenic and phosphorus found in excessive amounts in waters are toxic and/or carcinogenic and may cause health problems. Thus, the aim of this work was to investigate the sorption of aqueous Cr(VI), As(V), and P(V) on natural halloysite and halloysite grafted with diethanolamine. Halloysite (H) sample was obtained from the Intermark Company which exploits the Dunino deposits formed as a result of basalt weathering, located in NW Poland near Legnica. The modification consisted of two steps. Firstly, the intercalate of the mineral with dimethyl sulfoxide (DMSO) was prepared. For this purpose 12.5 g of the mineral was dispersed in a mixture of 90 mL DMSO and 10 mL H2O for 5 days at room temperature (HDMSO sample). Secondly, the HDMSO was refluxed with diethanolamine (DEA) (100 g/L ratio) for 24 h at 180°C under argon flow. The centrifuged product (HD) was washed with isopropanol and subsequently with water to remove unreacted DEA and DMSO remnants and dried at 65°C. The material was characterized using XRD, IR and SEM methods. Adsorption experiments were conducted at 5 mmol/L Cr(VI), As(V), and P(V) concentration in the single-element system for initial pH 3, 6, 9 and in mixed double-element system (1:1 anion molar ratio) for the initial pH 3. For the equilibrium studies, the H and HD samples were shaken in adequate solution (solid/solution ratio 20 g/L) for 24 h at room temperature. Afterwards, the supernatant solution was analyzed for anions. The Cr(VI) concentration was determined by 1.5-diphenylcarbazide method, while the P(V) and As(V) concentrations were determined by molybdenum blue method. The XRD confirmed the formation of an intercalate with DMSO as the characteristic d001 peak at 11.2 Å appeared. After DMSO treatment, the intensity of four distinct bands in the OH stretching region (3,700-3,600 cm-1), which are characteristic for the natural halloysite, changed as a result of interaction between the mineral and DMSO. Also the bands attributed to the C-H stretching vibrations of DMSO methyl groups were found at 3,021, 2,937 and 2,920 cm-1. The interlayer grafting of DEA led to fixing of basal spacing at 10.34 Å. After water washing the IR spectra showed only bands related to the grafted DEA molecules, which confirms the derivative stability (Matusik & Bajda 2013). As the cation exchange capacity (CEC) of the H sample is low, the adsorption process takes place mainly at the crystal edges. It was assumed that the protonated amine group of DEA will attract the anionie species. The results show that such modification does not improve the anion sorption properties of halloysite. The sorption increased only in case of Cr(VI) from 4 to 9 mmol/kg at initial pH 9 (single-element system). The highest sorption was observed in acidic system due to lack of competitive OH ions. In this case, sorption of Cr(VI) was 27 mmol/kg for H and 28 mmol/kg for HD. In contrast, the H adsorbed 108 mmol P(V)/kg in single-element system, while HD adsorbed only 50 mmol P(V)/kg. Adsorption of the As(V) was higher for the H sample and equal to 67 mmol/kg. A comparison of the obtained results for P(V) and As(V) to the sorption efficiency of HDT-MA-modified zeolites (respectively: 80 mmol/kg and 35 mmol/kg) and HDTMA-modified smectites (respectively: 75 mmol/kg and 45 mmol/kg) indicates, that the natural halloysite is a promising sorbent with regard to the studied anions (Mozgawa et al. 2011). In the single-element system the sorption increased as follows: P > As >>Cr. In turn, in the double-element system the competitive sorption was observed. Thus, the sorption of P(V) was lowered in the presence of Cr(VI), while in competitive P(V)-As(V) system the sorption of As(V) dominated. The mechanisms which contribute to the sorption were mainly surface complexation. Further investigation requires thermodynamic studies and the use of i.e. XPS (X-ray photoelectron spectroscopy).

17

Compressibility of kaolinite treated with fly ash from fluidized bed combustion

Knapik K., Bzówka J., Russo G.

Budownictwo i Architektura

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2014

|

Vol. 13, nr 2

33--38

EN

Waste products such as fly ash can be an economically advantageous alternative for lime and cement in ground improvement techniques. Current state of knowledge indicates the possibility of using this material successfully in various engineering projects. However, the chemical composition of fly ash is related to the type of coal and combustion technology used in power plant. This fact indicates need for further studies aiming determination the effect of fly ash addition on soil properties. Rate of soil improvement considered in macro level includes designation of treated soil mechanical properties, inter alia compressibility characteristics. Presented results of laboratory tests are a part of a larger experimental work aiming to determine the suitability of fly ash from fluidized bed combustion for the purpose of soil strengthen with the use of selected ground improvement.

PL

Odpady takie jak popioły lotne mogą stanowić korzystną pod względem ekonomicznym alternatywę dla wapna i cementu w technikach wzmacniania podłoża gruntowego. Obecny stan wiedzy wskazuje na możliwość wykorzystywania tego materiału z powodzeniem w różnych przedsięwzięciach inżynierskich. Jednakże skład chemiczny popiołów lotnych jest związany z rodzajem węgla oraz technologią spalania przyjętą w elektrowni. Ten fakt wskazuje na konieczność poszerzania bazy doświadczalnej, mającej na celu określenie wpływu dodatku popiołu lotnego na właściwości gruntu. Stopień wzmocnienia gruntu rozpatrywany w skali makro obejmuje oznaczenie mechanicznych właściwości gruntu wzmacnianego, w tym charakterystyki ściśliwości. Przedstawione wyniki badań laboratoryjnych stanowią część projektu badawczego, mającego na celu określenie przydatności popiołów lotnych pochodzących z fluidalnego spalania węgla do celów wzmacniania gruntu przy wykorzystaniu wybranych technik wzmacniania podłoża gruntowego.

18

Experimental study on electrokinetic of kaolinite particles in aqueous suspensions

Min F., Zhao Q., Liu L.

Physicochemical Problems of Mineral Processing

|

2013

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Vol. 49, iss. 2

659--672

EN

Influence of aqueous phase properties and process parameters on kaolinite particle zeta potential was quantified by electrophoresis experiments. The results indicated that pH strongly altered the zeta potential of kaolinite and it decreases at the beginning and then increases in the range of pH = 2–13. The activity of different cations changes the zeta potential and has the following tendency of Al3+ > Ca2+ > Mg2+ > Na+ and the zeta potential increases due to heterocoagulation of different mineral particles in suspension. It was found that the zeta potential of kaolinite particles increases after the suspension was stirred and decreases at the beginning, and then increases with soaking time. The FTIR results showed that the zeta potential takes into account ion adsorption and the change of Si–O, Al–O and Al–OH groups on the surface of the kaolinite particles.

19

Potassium response in some Malawi soils

Lakudzala D. D.

International Letters of Chemistry, Physics and Astronomy

|

2013

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Vol. 8, iss. 2

175-181

EN

Potassium (K) response curves were generated for some Malawi soils using four different rates of potassium fertilizer, with grass being used to estimate plant availability. The study was conducted to find the point of maximum response for potassium. The soils were characterized, limed and fertilized with equal amounts of nitrogen. Potassium was applied at four rates: 0.0, 0.1, 0.2 and 0.4 me K/100 cm3 soil. The K treated soils were put in pots and cropped with grass. The grass was harvested six weeks after planting, dried and weighed. In general, addition of potassium resulted in increased growth of grass in all soils, with some soils showing better response than others. For montmorillonitic soils and soils with mixed mineralogy response was linear up to the highest rate of 0.4 me K/100 cm3. Apparently the 0.4 me K/100 cm3 soil was not enough to give maximum yield for these potassium depleted soils. For the kaolinitic soils 0.4 me K/100 cm3 soil was beyond point of maximum response. The variation of response to added potassium in the different soils calls for soil specific fertilizer additions. Smallholder farmers should move from blanket (crop specific) fertilizer recommendations currently being used to crop and soil specific fertilizer recommendations. Basal fertilizer dressings (starter packs) should always contain potassium. Correlation and calibration studies should be conducted to establish a potassium low optimum level for Malawi soils.

20

Clay minerals as palaeoenvironmental indicators in the Bathonian (Middle Jurassic) ore-bearing clays from Gnaszyn, Kraków-Silesia Homocline

Dudek T.

Acta Geologica Polonica

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2012

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Vol. 62, no. 3

297-305

EN

This paper reports the results of X-ray diffraction quantitative mineralogical studies of the clay-rich Middle Jurassic sedimentary rocks from Gnaszyn, central Poland and their palaeoenvironmental interpretation. The palaeoenvironmental interpretation is aided by the fact that the sediments have not been significantly altered by diagenesis. The mineral composition is uniform throughout the succession: quartz, K-feldspar, plagioclase, calcite, gypsum, anhydrite, pyrite, illite, kaolinite, chlorite, and glauconite. The clay assemblage is dominated by illite, which alone accounts for about 20 wt% of the total mineral content. Kaolinite amounts usually <10 wt% and chlorite and glauconite occur in subordinate quantities. The clay mineral assemblage is largely of detrital origin and indicates rather cool and/or dry climatic conditions favouring mechanical erosion of the source rocks.