scholarly journals Use of silver–bentonite in sorption of chloride and iodide ions

2020 ◽  
Vol 326 (3) ◽  
pp. 1795-1804
Author(s):  
Dóra Buzetzky ◽  
Noémi M. Nagy ◽  
József Kónya
Keyword(s):  
Interlayer Space ◽  
Exchange Process ◽  
Silver Ions ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Precipitation Process ◽  
High Concentration ◽  
Iodide Ions ◽  
Ion Exchange Process ◽  
Increasing Temperature

AbstractAg–bentonite was prepared by ion exchange process to sorb iodide and chloride ions in batch experiments. The modified bentonite was examined with XRF and XRD. 75% of the cation exchange capacity was exchanged by silver ions. It was found that the sorption of chloride ions is an exothermic precipitation process because the solubility decreases with increasing temperature. In the case of iodide sorption, the dissolution of AgI was observed under high concentration of non-radioactive iodide ions, which is well known in analytical chemistry. The phenomenon occurs not only in the bulk aqueous phase but also in the interlayer space of montmorillonite.

scholarly journals Amberlite IRC-718 ion chelating resin extraction of hazardous metal Cr (VI) from aqueous solutions: equilibrium and theoretical modeling

2021 ◽  
Author(s):  
Abdelhamid Addala ◽  
Moussa Boudiaf ◽  
Maria Elektorowicz ◽  
Embarek Bentouhami ◽  
Yacine Bengeurba
Keyword(s):  
Ion Exchange ◽  
Aqueous Solutions ◽  
Exchange Process ◽  
Ion Exchange Resin ◽  
Exchange Capacity ◽  
Chelating Resin ◽  
Exchange Potential ◽  
Chromium Vi ◽  
Ion Exchange Process ◽  
Hazardous Metal

Abstract Under varied conditions, the IRC 718 ion-exchange resin is used to extract chromium (VI) ions from aqueous solutions. On chromium (VI) removal effectiveness, the effects of adsorption dosage, contact time, beginning metal concentration, and pH were examined. The batch ion exchange process reached equilibrium after around 90 minutes of interaction. With an initial chromium (VI) concentration of 0.5 mg/dm3, the pH-dependent ion-exchange mechanism revealed maximal removal in the pH 2.0–10 range . The adsorption mechanism occurs between Cr(VI) determined as the electron acceptor, and IRC 718 determined as the electron donor. The equilibrium ion-exchange potential and ion transfer quantities for Amberlite IRC 718 were calculated using the Langmuir adsorption isotherm model. The overall ion exchange capacity of the resin was determined to be 187.72 mg of chromium (VI)/g of resin at an ideal pH of 6.0.

scholarly journals The Li+, Na+ and K+ ion exchange reaction process on the surface of mixed oxide SiO2/TiO2/Sb2O5 surface prepared by the sol-gel processing method

2005 ◽  
Vol 30 (1) ◽  
pp. 51-58 ◽  
Author(s):  
C. U. Ferreira ◽  
J. E. Gonçalves ◽  
Y. V. Kholin ◽  
Y. Gushikem
Keyword(s):  
Ion Exchange ◽  
Mixed Oxide ◽  
Exchange Process ◽  
Sol Gel ◽  
Exchange Capacity ◽  
Processing Method ◽  
Exchange Property ◽  
Ion Exchange Process ◽  
Ion Exchange Reaction ◽  
Gel Processing

The porous mixed oxide SiO2/TiO2/Sb2O5 obtained by the sol-gel processing method presented a good ion exchange property and a high exchange capacity towards the Li+, Na+ and K+ ions. In the H+/M+ ion exchange process, the H+ / Na+ could be described as presenting an ideal character. The ion exchange equilibria of Li+ and K+ were quantitatively described with the help of the model of fixed tetradentate centers. The results of simulation evidence that for the H+ / Li+ exchange the usual situation takes place: the affinity of the material to the Li+ ions is decreased with increasing the degree of ion exchange. On the contrary, for K+ the effects of positive cooperativity, that facilitate the H+ / K+ exchange, were revealed.

Highly efficient biocide silver-doped soda lime glass for application in water quality optical sensors

2020 ◽  
Vol 111 (10) ◽  
pp. 857-862
Author(s):  
Branimir Bajac ◽  
Jovana Stanojev ◽  
Slobodan Birgermajer ◽  
Milena Radojevic ◽  
Jovan Matovic
Keyword(s):  
Spectral Range ◽  
Optical Sensors ◽  
Exchange Process ◽  
Silver Ions ◽  
Soda Lime ◽  
Soda Lime Glass ◽  
Ion Exchange Process ◽  
Surface Modified ◽  
Very High

Abstract In the last decade, biocidal materials have been extensively researched and applied as a coating for various touchscreen devices, in medicine and civil engineering. This research addresses important practical issues in application of surface- modified biocidal glass in water, and inspects optical properties in the spectral range between 350 nm and 500 nm, the range important for bacteria fluorescence detection. Testing of biocidal efficiency has been conducted in an environment rich with microorganisms and algae. To incorporate silver ions in soda lime glass plates, an ion-exchange process in a molten bath was used. The optical characterization of as-synthesized samples indicates very high transparency, above 90% at 440 nm, specifically important for escherichia coli detection. fter 140 days in the bioreactor, it was found that glass heated for 15 min at 350 0C produced best results, maintaining transparency above 85% in spectral range from 350 nm to 1000 nm.

Corrosion Risk of Stainless Steel Facilities in the Coastal Regions of Taiwan

2013 ◽  
Vol 479-480 ◽  
pp. 1097-1100 ◽  
Author(s):  
Tailin Huang ◽  
Heui Yung Chang
Keyword(s):  
Stainless Steel ◽  
Exchange Process ◽  
Chloride Ions ◽  
Management Approach ◽  
Coastal Regions ◽  
Extrinsic Factors ◽  
Industrial Facilities ◽  
Ion Exchange Process ◽  
Dynamic Risk Management ◽  
Corrosion Risk

In Taiwan, many industrial facilities are located in coastal regions. A large portion of those facilities are constructed with stainless steel. Over time, sodium chloride from seawater vapor would deposit on the surface of the facilities and the chloride ions in it can lead to corrosion and cracks. This process is the so-called stress corrosion cracking (SCC). Theoretically, the SCC failures increase with the level of residual stress created by the welding and cold working processes. Practically, however, the corrosion risk is governed by various intrinsic and extrinsic factors that interact as a complex process. In this paper, we propose a dynamic approach for controlling the SCC risk. Firstly, we review some recent experimental work and filed investigations on stainless steel facilities in Taiwan. Following that, a dynamic risk management approach is explained and applied to develop a research roadmap for controlling the complex corrosion risk. In sum, we find that the best way to control the corrosion risk of the facilities is to remove the chlorides from the air by an ion exchange process accompanied with continuous monitoring and maintenance efforts during their operation life cycle.

scholarly journals Organomodified kaolin as filler for natural rubber

2015 ◽  
Vol 21 (4) ◽  
pp. 477-484 ◽  
Author(s):  
Ogbemudia Ogbebor ◽  
Felix Okieimen ◽  
David Ogbeifun ◽  
Uzoma Okwu
Keyword(s):  
Natural Rubber ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Ammonium Bromide ◽  
X Ray Diffraction ◽  
Elongation At Break ◽  
Ion Exchange Process ◽  
Rubber Compounds ◽  
Natural Rubber Composites ◽  
Better Than

Organokaolin, through the incorporation of cationic hexadecyltrimethyl ammonium bromide in various concentrations (50%, 100% and 200% cation exchange capacity, CEC) into kaolin clay?s interlayer spaces have been prepared. This was characterized using XRD and FTIR to get information on sample structural composition and characteristic bonds on modification. These clays were further used as filler in natural rubber compounds with a semi-ultra; delayed action accelerator scheme. The X-ray diffraction analysis showed marginal increase in basal (d(001)) spacing of kaolin platelets from 4.01 to 4.90 nm. Changes in the clay?s molecular environment induced by ion-exchange process were followed by FTIR measurements revealing various CTAB+ influenced absorption peaks as modification progressed. Cure characteristics, scorch (ts2) and cure (t90) time of the organokaolin filled natural rubber composites was observed better than that of the 40 phr bulk kaolin across the CEC organophilization concentrations and filler loadings studied. Vulcanizate properties showed considerable increase in M100, M200, M300, TS, and elongation at break (%) indicating its potential as an organomodified filler. Hardness (IRHD) and abrasion resistance showed similar trend as tensile properties, with the incorporation of organoclay.

Template-assisted Synthesis of Polymer - Li Composites with Fractal Patterns

2011 ◽  
Vol 64 (2) ◽  
pp. 190
Author(s):  
Li Tan ◽  
Ge Wang ◽  
Wenjun Dong ◽  
Mu Yang ◽  
Jingning Shan ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Interlayer Space ◽  
Fractal Structure ◽  
Exchange Process ◽  
Controlled Polymerization ◽  
Equilibrium Conditions ◽  
Ion Exchange Process ◽  
Reverse Ion Exchange ◽  
Fractal Patterns ◽  
Template Assisted Synthesis

A facile route for the synthesis of polymer–lithium halide composites with fractal patterns ranging from the nano- to microscale has been developed by employing a two-step template-assisted approach at room temperature. First, polydimethyl diallyl ammonium chloride (PDDA) is synthesized through the controlled polymerization of the monomers inside the interlayers of montmorillonite (MMT). Subsequently, the PDDA-MMT is used as a template to react with LiCl/THF solution. The polymer segments were separated from the MMT interlayer space by employing a reverse ion-exchange process. It was found that the morphology of the fractal patterns can be controlled by varying the polymerization concentration of the monomer. It is concluded that the limited polymerization of PDDA and the reverse ion-exchange process produce the non-equilibrium conditions that serve as the critical factors in forming the fractal patterns. The mechanism for the formation of the fractal structure is proposed and discussed in detail.

scholarly journals Anionic Exchange Membrane for Photo-Electrolysis Application

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2991
Author(s):  
Carmelo Lo Vecchio ◽  
Alessandra Carbone ◽  
Stefano Trocino ◽  
Irene Gatto ◽  
Assunta Patti ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Light Transmission ◽  
Cupric Oxide ◽  
Low Cost ◽  
Polymer Electrolyte Membrane ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Electrolyte Membrane ◽  
Ion Exchange Process ◽  
Exchange Membrane

Tandem photo-electro-chemical cells composed of an assembly of a solid electrolyte membrane and two low-cost photoelectrodes have been developed to generate green solar fuel from water-splitting. In this regard, an anion-exchange polymer–electrolyte membrane, able to separate H2 evolved at the photocathode from O2 at the photoanode, was investigated in terms of ionic conductivity, corrosion mitigation, and light transmission for a tandem photo-electro-chemical configuration. The designed anionic membranes, based on polysulfone polymer, contained positive fixed functionalities on the side chains of the polymeric network, particularly quaternary ammonium species counterbalanced by hydroxide anions. The membrane was first investigated in alkaline solution, KOH or NaOH at different concentrations, to optimize the ion-exchange process. Exchange in 1M KOH solution provided high conversion of the groups, a high ion-exchange capacity (IEC) value of 1.59 meq/g and a hydroxide conductivity of 25 mS/cm at 60 °C for anionic membrane. Another important characteristic, verified for hydroxide membrane, was its transparency above 600 nm, thus making it a good candidate for tandem cell applications in which the illuminated photoanode absorbs the highest-energy photons (< 600 nm), and photocathode absorbs the lowest-energy photons. Furthermore, hydrogen crossover tests showed a permeation of H2 through the membrane of less than 0.1%. Finally, low-cost tandem photo-electro-chemical cells, formed by titanium-doped hematite and ionomer at the photoanode and cupric oxide and ionomer at the photocathode, separated by a solid membrane in OH form, were assembled to optimize the influence of ionomer-loading dispersion. Maximum enthalpy (1.7%), throughput (2.9%), and Gibbs energy efficiencies (1.3%) were reached by using n-propanol/ethanol (1:1 wt.) as solvent for ionomer dispersion and with a 25 µL cm−2 ionomer loading for both the photoanode and the photocathode.

scholarly journals Sorption of pertechnetate anion by cation modified bentonites

2019 ◽  
Vol 322 (3) ◽  
pp. 1771-1776
Author(s):  
D. Buzetzky ◽  
E. M. Kovács ◽  
M. N. Nagy ◽  
J. Kónya
Keyword(s):  
Ion Exchange ◽  
Cation Exchange ◽  
Cation Exchange Capacity ◽  
Metal Ion ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Ion Exchange Process

Abstract Pertechnetate anion sorption was investigated on modified bentonites. Mn-, Cr-, Sn-bentonites were prepared by ion exchange process to sorb radioactive pertechnetate ions. In the case of Mn-, Cr-bentonite the sorb amount of metal ion was 70–90% of the cation exchange capacity of the bentonite which is expected. Interestingly in the case of Sn-bentonite this amount was 1.42 times higher than the cation exchange capacity. On Mn-bentonite the sorption was 35% at pH 5. The removal of pertechnetate ions was 100% on Cr-, Sn-bentonites and the significant sorption was achieved below 650 mV/SHE.

scholarly journals Removal of quaternary ammonium compounds in ion exchange process

2019 ◽  
Vol 116 ◽  
pp. 00034
Author(s):  
Aleksandra Klimonda ◽  
Izabela Kowalska
Keyword(s):  
Ion Exchange ◽  
Cationic Surfactant ◽  
Exchange Process ◽  
Exchange Capacity ◽  
Resin Matrix ◽  
Ph Change ◽  
Ion Exchange Process ◽  
Batch Tests ◽  
Exchange Resins ◽  
Surfactant Removal

The study attempted to evaluate the effectiveness of ion exchange process in cationic surfactant (benzalkonium chloride, BAC) removal from model solutions. Four commercial cation-exchange resins were chosen for the batch tests in four doses (2.5–20 mL L-1). The experiments included evaluation of the following parameters on ion exchange efficiency: resin characteristics and dose, presence of inorganic salt and pH of treated solution. The ion exchange process was found to be very effective in cationic surfactant removal – two of tested resins allowed to remove up to 80% of contaminant after contact time of 40 minutes, the last two – after 60 minutes of mixing in all range of doses. The presence of electrolyte neither pH change has no essential effect on surfactant removal efficiency. The analysis of the ion exchange isotherms showed that the strongly-acidic macroporous resin C150 H was characterized by the highest BAC ion exchange capacity (153.8 mg mL-1), while the weakly-acidic gel resin C104 showed the best affinity of the exchanged ions to the resin matrix.

scholarly journals Mathematical modeling of the ion exchange processes of sodium clinoptilolite with heavy metal ions from residual waters

2005 ◽  
Vol 11 (4) ◽  
pp. 209-212 ◽  
Author(s):  
Claudia Cobzaru ◽  
Spiridon Oprea
Keyword(s):  
Mathematical Modeling ◽  
Ion Exchange ◽  
Exchange Process ◽  
Correlation Coefficients ◽  
Solution Concentration ◽  
Exchange Capacity ◽  
Response Surfaces ◽  
Ion Exchange Process ◽  
Model Equations ◽  
Necessary And Sufficient

The ion-exchange capacity of volcanic tuff in the Na+ form (70% clinoptilolite content), used for removing heavy metals in residual waters, was investigated under different conditions (temperature, time and exchange solution concentration). These parameters are necessary and sufficient for the mathematical modeling of the ion-exchange process. The corresponding mathematical models show common characteristics due to the good arrangement of the experimental points on the response surfaces and correlation coefficients close to unity. Differences appear with respect to the shape of the response surface and model equations. .

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