scholarly journals Application of Modified Bentonites for Arsenite (III) Removal from Drinking Water

2018 ◽  
Vol 63 (1) ◽  
pp. 113-121 ◽  
Author(s):  
Dóra Buzetzky ◽  
Noémi Csilla Tóth ◽  
Noémi M. Nagy ◽  
József Kónya
Keyword(s):  
Active Sites ◽  
Ammonium Acetate ◽  
Exchange Process ◽  
Sorption Isotherms ◽  
Basal Spacing ◽  
Similar Amount ◽  
X Ray Diffraction ◽  
Ion Content ◽  
X Ray ◽  
Ion Exchange Process

Four modified bentonites (La(III), Ce(III), Y(III), Fe(III)) were prepared by ion exchange process to remove arsenite (III) ions from water. The modified bentonites were examined with X-ray fluorescence spectroscopy (XRF) and X-ray diffraction (XRD). The rare earth (REE) and Fe(III) ion content in bentonite was higher than the CEC values obtained by ammonium acetate method related to trivalent ions (2.7 x 10-4 mol g-1). The kinetics, equilibrium time, sorption isotherms and desorption experiments were examined. Lanthanum, yttrium and cerium bentonite can bind similar amount of arsenite(III) ions. Iron-bentonite cannot bind significant amounts of arsenite ions. The active sites and the solubilities of the sorption complex were determined. Arsenite (III) ions sorb in the interlayer space as REEAsO3. The solubility of the arsenite complex was two orders of magnitude smaller than that of the phosphate complex. After desorption the eluted amount of arsenite (III) was 55 % related to the sorbed amount of arsenite. The d(001) basal spacing of modified bentonites and that of after sorption and desorption was measured. After the sorption of arsenite ion on lanthanum bentonite, the d(001) basal spacing of montmorillonite was decreased and after desorption an increase in d(001) basal spacing was observed again. Modified bentonites can be used for removing arsenic ions from water.

The Adsorption of Aromatic, Heterocyclic and Cyclic Ammonium Cations by Montmorillonite

Clay Minerals ◽  
1973 ◽  
Vol 10 (2) ◽  
pp. 61-69 ◽  
Author(s):  
E. F. Vansant ◽  
J. B. Uytterhoeven
Keyword(s):  
Ion Exchange ◽  
Exchange Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Organic Ions ◽  
Ion Exchange Process ◽  
Proton Adsorption ◽  
Acidic Compounds ◽  
Aromatic Heterocyclic ◽  
Acid Character

AbstractThe adsorption of organic ions derived from ammonium, containing aromatic and saturated rings, was studied using different techniques. The ions with acid character produced a complicated set of reactions including aluminium extraction, proton adsorption, a real ion-exchange with the organic ions and an excess adsorption of ammonium salts. With non-acidic compounds only a stoichiometric ion-exchange process was observed. X-ray diffraction and infrared spectroscopy were used to determine the orientation of the organic ions and to characterize the nature of the co-adsorbed organic material.

scholarly journals Bioimmobilization of lead by Bacillus subtilis X3 biomass isolated from lead mine soil under promotion of multiple adsorption mechanisms

2019 ◽  
Vol 6 (2) ◽  
pp. 181701 ◽  
Author(s):  
Weichuan Qiao ◽  
Yunhao Zhang ◽  
Hao Xia ◽  
Yang Luo ◽  
Si Liu ◽  
...  
Keyword(s):  
Bacillus Subtilis ◽  
Photoelectron Spectroscopy ◽  
Extracellular Polymeric Substances ◽  
Exchange Process ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Mechanisms ◽  
Ion Exchange Process ◽  
Biosorption Process ◽  
Amine Groups

In this study, a lead-resistant bacterium, Bacillus subtilis X3, was used to prepare a lead bioadsorbent for immobilization and removal of lead in lead solution. The lead shot precipitate was analysed by scanning electron microscopy combined with energy dispersive X-ray fluorescence microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and X-ray photoelectron spectroscopy. The adsorbed lead was mainly mineralized to form Pb 5 (PO 4 ) 3 OH, Pb 10 (PO 4 ) 6 (OH) 2 and Pb 5 (PO 4 ) 3 Cl; however, other mechanisms that can also promote the mineralization of lead should not be ignored. For example, Na + and Ca 2+ on the cell wall surface were exchanged with Pb 2+ in solution, which confirmed that the ion-exchange process occurred before mineralization. Moreover, adsorption bridging caused by extracellular polymeric substances also accelerated the further aggregation of lead, and the biomass was encapsulated by lead gradually. Hydroxyl, carbonyl, carboxyl and amine groups were not observed in lead mineral crystals, but the complexation between lead and these groups still benefited the mineralization of lead. The valence of Pb(II) was not changed after mineralization, which indicated that the biosorption process was not a redox reaction. Finally, biosorption occurred on the outer surface of the cell, but its specific surface area was relatively small, limiting the amount and efficiency of biosorption.

Interactions between hydroxy-aluminium species and homoionic Na- and Ca-montmorillonite particles, as manifested by ζ potential, suspension stability and X-ray diffraction

Clay Minerals ◽  
1988 ◽  
Vol 23 (2) ◽  
pp. 213-224 ◽  
Author(s):  
J. Y. Bottero ◽  
M. Bruant ◽  
J. M. Cases
Keyword(s):  
Molecular Weight ◽  
Electrokinetic Potential ◽  
Exchange Process ◽  
Basal Spacing ◽  
Suspension Stability ◽  
X Ray Diffraction ◽  
Clay Particles ◽  
X Ray ◽  
Low Concentrations ◽  
Aluminium Species

The interactions between and higher molecular weight hydroxy-Al species with homoionic Na- and Ca-montmorillonite have been studied by measuring adsorption of the hydroxy-Al on to the clay, turbidity of the resulting suspensions, electrokinetic potential, and d(001) basal spacing. The isolated “Al13” ions are adsorbed according to a cation-exchange process which causes flocculation of the tactoids at low concentrations. At higher concentrations, the adsorption of either isolated “Al13” or/and higher molecular weight species is mainly responsible for the dispersion of clay particles with a net positive surface charge (ζ ∼ + 50 mV). Consequently, the tactoids are destroyed.

scholarly journals Thorium(IV) adsorption onto multilayered Ti3C2Tx MXene: a batch, X-ray diffraction and EXAFS combined study

2021 ◽  
Vol 28 (6) ◽  
Author(s):  
Lin Wang ◽  
Wuqing Tao ◽  
Enzhao Ma ◽  
Zijie Li ◽  
Peng Ren ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Active Sites ◽  
Adsorption Mechanism ◽  
Adsorption Process ◽  
Exchange Process ◽  
Outer Sphere ◽  
Strong Acid ◽  
X Ray Diffraction ◽  
X Ray ◽  
Adsorption Sites

The interlayer regulation of layered environmental adsorption materials such as two-dimensional early transition metal carbides and carbonitrides (MXenes) plays an important role in their purification performance for specific pollutants. Here the enhanced uptake of ThIV by multilayered titanium carbides (Ti3C2Tx) through a hydrated intercalation strategy is reported. ThIV adsorption behaviors of three Ti3C2Tx samples with different c lattice parameters were studied as a function of contact time, pH, initial concentration, temperature and ion strength in batch experiments. The results indicated that the ThIV uptake was pH and ionic strength dependent, and the adsorption process followed the pseudo-second-order kinetics and the heterogeneous isotherm (Freundlich) model. Thermodynamic data suggested that the adsorption process of all MXene samples was a spontaneous endothermic reaction. The dimethyl sulfoxide intercalated hydrated Ti3C2Tx featured the largest interlayer space and exhibited the highest ThIV adsorption capacity (162 mg g−1 at pH 3.4 or 112 mg g−1 at pH 3.0), reflecting the significant increase in available adsorption sites from Ti3C2Tx interlayers. The adsorption mechanism has been clarified based on adsorption experiments and spectroscopic characterizations. An ion exchange process was proposed for the interaction between hydrated MXenes and ThIV, where H+ from surface [Ti−O]−H+ groups were the primary active sites on Ti3C2Tx. Extended X-ray absorption fine structure (EXAFS) fitting results, in combination with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR) analyses, clearly indicated that ThIV mainly formed the outer-sphere complexes on Ti3C2Tx surface through electrostatic interaction under strong acid conditions, while at pH > 3.0 the adsorption mechanism was determined by inner-sphere coordination and electrostatic interaction together.

Interactions of imidacloprid with organicand inorganic- exchanged smectites

Clay Minerals ◽  
2001 ◽  
Vol 36 (2) ◽  
pp. 267-274 ◽  
Author(s):  
L. Cox ◽  
M. C. Hermosin ◽  
W. C. Koskinen ◽  
J. Cornejo
Keyword(s):  
Hydrophobic Interactions ◽  
Sorption Isotherms ◽  
Basal Spacing ◽  
X Ray Diffraction ◽  
X Ray ◽  
Alkyl Chains ◽  
Alkyl Cations ◽  
Ft Ir ◽  
Diffraction Patterns ◽  
Alkylammonium Cation

AbstractSorption of the polar insecticide imidacloprid on organic-saturated octadecylammonium (C18) and dioctadecyldimethylammonium (DOD) and inorganic- (Fe- ) saturated Wyoming (W) and Arizona (A) montmorillonites has been investigated. Sorption isotherms were fitted to the Freundlich equation. Imidacloprid-montmorillonite complexes were studied by X-ray diffraction and FT-IR techniques. Imidacloprid sorption coefficients, Kf, decreased in the order WC18> AC18> WFe> WDOD≥ ADOD. The low layer charge and saturation by primary alkylammonium cation facilitates sorption of imidacloprid in the interlayer of the smectite, corroborated by the increase in basal spacing observed in X-ray diffraction patterns and by the presence of absorption band shifts in FT-IR spectra. Imidacloprid sorbs in the interlayer space of smectite mainly by hydrophobic interactions with the alkyl chains in organic smectites and with the uncharged siloxane surface in Fe(III)-smectite. Further polar bonds between the NO2 group of imidacloprid and the NH of the primary alkyl cations and protonation of imidacloprid in Fe-smectites enhanced sorption in these cases.

Role of the Structure and Electronic Properties of Fe2O3-MoO3 Catalyst on the Dehydration of Isopropyl Alcohol

1993 ◽  
Vol 58 (7) ◽  
pp. 1591-1599 ◽  
Author(s):  
Abd El-Aziz A. Said
Keyword(s):  
Active Sites ◽  
Isopropyl Alcohol ◽  
Oxide Catalyst ◽  
Flow System ◽  
Charge Carriers ◽  
X Ray Diffraction ◽  
X Ray ◽  
Catalyst Composition ◽  
Surface Active

Molybdenum oxide catalyst doped or mixed with (1 - 50) mole % Fe3+ ions were prepared. The structure of the original samples and the samples calcined at 400 °C were characterized using DTA, X-ray diffraction and IR spectra. Measurements of the electrical conductivity of calcined samples with and without isopropyl alcohol revealed that the conductance increases on increasing the content of Fe3+ ions up to 50 mole %. The activation energies of charge carriers were determined in presence and absence of the alcohol. The catalytic dehydration of isopropyl alcohol was carried out at 250 °C using a flow system. The results obtained showed that the doped or mixed catalysts are active and selective towards propene formation. However, the catalyst containing 40 mole % Fe3+ ions exhibited the highest activity and selectivity. Correlations were attempted to the catalyst composition with their electronic and catalytic properties. Probable mechanism for the dehydration process is proposed in terms of surface active sites.

Physicochemical and Catalytic Properties of Spinels Formed by Solid-Solid Interaction Between Fe2O3and V2O5

1996 ◽  
Vol 61 (8) ◽  
pp. 1131-1140 ◽  
Author(s):  
Abd El-Aziz Ahmed Said
Keyword(s):  
Vanadium Oxide ◽  
Active Sites ◽  
Catalyst Surface ◽  
Catalytic Properties ◽  
Flow System ◽  
Oxide Catalysts ◽  
X Ray Diffraction ◽  
Selective Catalyst ◽  
X Ray ◽  
Solid Catalysts

Vanadium oxide catalysts doped or mixed with 1-50 mole % Fe3+ ions were prepared. The structure of the original samples and those calcined from 200 up to 500 °C were characterized by TG, DTA, IR and X-ray diffraction. The SBET values and texture of the solid catalysts were investigated. The catalytic dehydration-dehydrogenation of isopropanol was carried out at 200 °C using a flow system. The results obtained showed an observable decrease in the activity of V2O5 on the addition of Fe3+ ions. Moreover, Fe2V4O13 is the more active and selective catalyst than FeVO4 spinels. The results were correlated with the active sites created on the catalyst surface.

scholarly journals Isoterma dan Termodinamika Adsorpsi Kation Cu2+ Fasa Berair pada Lempung Cengar Terpilar

2012 ◽  
Vol 14 (1) ◽  
pp. 7
Author(s):  
Syaiful Bahri ◽  
Muhdarina Muhdarina ◽  
Nurhayati Nurhayati ◽  
Fitri Andiyani
Keyword(s):  
Gibbs Energy ◽  
Sodium Acetate ◽  
Atmospheric Condition ◽  
Freundlich Isotherm ◽  
Pillared Clays ◽  
Basal Spacing ◽  
New Mineral ◽  
X Ray Diffraction ◽  
Clay Suspension ◽  
X Ray

Pillared Cengar clay have been synthesized by two methods, first clay suspension is directly mixed into aqueous solution of hydroxy-aluminum polycations (WK) and second by mixing the clay suspension into the solution of sodium acetate and hydroxy-aluminumpolycations (SAK) sequentially. Both clays were calcined in air on atmospheric condition. Diffraction pola, surface morphology and cationexchange capacity of the pillared clays were characterized using X Ray Diffraction (XRD), Scanning Electron Microscopy (SEM) andvisible spectrophotometry methods, respectively. The pillared clays showed increases of basal spacing from 3.57 Å to 4.55 Å and smectiteas a new mineral. Morphology of SAK has more heterogeneous surface with small plates and agglomeration of grains compare with WKwhich small plates. Adsorption of aqueous cation of Cu 2+ were studied on various variables of initial concentration as well as temperatures.As the result, adsorption of cation Cu 2+ on pillared Cengar clay is corresponding to Freundlich isotherm, while the adsorption capacity ofWK on cation Cu 2+ is slightly lower than SAK. The thermodynamic aspect, the WK is reflected possessed exothermic processes withnegative entropy, increased in Gibbs energy and non spontaneous, while the SAK possessed endothermic processes having positive entropy,decreased in Gibbs energy and non spontaneous.

scholarly journals Pilarisasi Lempung Dengan Al/Cr sebagai Adsorben Minyak Sisa Pakai

2021 ◽  
Vol 1 (1) ◽  
pp. 13-18
Author(s):  
Tiska Eva Triandhani ◽  
Taslimah Taslimah ◽  
Sriyanti Sriyanti
Keyword(s):  
Basal Spacing ◽  
X Ray Diffraction ◽  
X Ray

Minyak goreng yang digunakan berulang kali dapat mengakibatkan kerusakan minyak. Salah satu solusi untuk menanganinya ialah dengan metode adsorpsi. Lempung terpilar Al/Cr telah dibuat sebagai adsorben minyak sisa pakai. Penelitian ini bertujuan untuk menentukan suhu optimum kalsinasi pada pemilaran lempung dengan Al/Cr dan menentukan kualitas minyak sisa pakai berdasarkan bilangan asam dan bilangan peroksida. Karakterisasi lempung terpilar menggunakan X-Ray Diffraction (XRD). Selanjutnya daya adsorpsi lempung terpilar terhadap minyak sisa pakai diukur menggunakan Spektrofotometer UV-Vis. Uji kualitas minyak dilakukan berdasarkan penentuan bilangan asam dan bilangan peroksida sesuai syarat mutu minyak goreng yaitu SNI 01-3741-2013. Hasil penelitian menunjukkan bahwa, pemilaran lempung Al/Cr dapat meningkatkan basal spacing. Lempung terpilar Al/Cr dengan suhu kalsinasi 400°C memiliki basal spacing terbesar yaitu fraksi ringan 18,84 Å dan fraksi berat 16,53 Å. Kemampuan lempung terpilar Al/Cr untuk adsorpsi minyak sisa pakai memiliki daya serap besar pada suhu kalsinasi 400°C  yaitu pada fraksi berat 9,16 % dan fraksi ringan 6,28 %. Lempung terpilar Al/Cr mampu menurunkan bilangan asam dan bilangan peroksida, bahwa semakin lama waktu kontak adsorpsi bilangan asam dan bilangan peroksida semakin menurun. Kata Kunci : Lempung terpilar Al/Cr, minyak sisa pakai, bilangan asam, bilangan         peroksida 

scholarly journals The Amounts of Water Adsorbed to the Surface of Clay Minerals at the Plastic Limit

2017 ◽  
Vol 64 (3-4) ◽  
pp. 155-162
Author(s):  
Aleksandra Gorączko ◽  
Andrzej Olchawa
Keyword(s):  
Surface Area ◽  
External Surface ◽  
Solid Phase ◽  
Water System ◽  
Basal Spacing ◽  
Plastic Limit ◽  
X Ray Diffraction ◽  
External Surface Area ◽  
X Ray ◽  
Water Layers

AbstractThe paper presents results of a study on the amount of water associated with the solid phase of the clay water system at the plastic limit. Two model monomineral clays, namely kaolinite, and montmorillonite, were used in the study. The latter was obtained by gravitational sedimentation of Na-bentonite (Wyoming).The calculated mean number of water molecule layers on the external surface of montmorillonite was 14.4, and water in interlayer spaces constituted 0.3 of the water mass at the plastic limit.The number of water layers on the external surface of kaolinite particles was 63, which was related to the higher density of the surface electrical charge of kaolinite compared to that of montmorillonite.The calculations were made on the basis of the external surface area of clays and the basal spacing at the plastic limit measured by an X-ray diffraction test. The external surface area of clays was estimated by measuring sorption at a relative humidity p/p0 = 0.5.

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