Insights of theoretical calculations and solubility equilibrium measurements into Ca2+-fluoride complexation and their dissociation behaviors in aqueous solutions: Implication for the association constant measured by fluoride ion selective electrodes

2021 ◽  
Author(s):  
ning zhang ◽  
Jianfeng Tang ◽  
Qiongqiong Luo ◽  
Shaoheng Wang ◽  
Dewen Zeng
Keyword(s):  
Aqueous Solutions ◽  
Association Constant ◽  
Theoretical Calculations ◽  
Fluoride Ion ◽  
Ion Selective Electrodes ◽  
Industrial Systems ◽  
Aqueous Environments ◽  
Fluoride Complexation ◽  
Solubility Equilibrium

Although the Ca2+-F− association is of great importance for aqueous environments and industrial systems containing F−, as well as for defluorination processes, many details of the association solvation structures and...

Novel triazole-based fluorescent probes for Pd2+ in aqueous solutions: design, theoretical calculations and imaging

The Analyst ◽  
2013 ◽  
Vol 138 (21) ◽  
pp. 6632 ◽  
Author(s):  
Ji-Ting Hou ◽  
Kun Li ◽  
Kang-Kang Yu ◽  
Mei-Zhen Ao ◽  
Xin Wang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Fluorescent Probes ◽  
Theoretical Calculations

scholarly journals Utilization to Remove Pb (II) Ions from Aqueous Environments Using Waste Fish Bones by Ion Exchange

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Bayram Kizilkaya ◽  
A. Adem Tekınay
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Mechanism ◽  
Cost Effective ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Fish Bones ◽  
Adsorption Capacities ◽  
Aqueous Environments ◽  
Equilibrium Data ◽  
Pseudo Second Order

Removal of lead (II) from aqueous solutions was studied by using pretreated fish bones as natural, cost-effective, waste sorbents. The effect of pH, contact time, temperature, and metal concentration on the adsorption capacities of the adsorbent was investigated. The maximum adsorption capacity for Pb (II) was found to be 323 mg/g at optimum conditions. The experiments showed that when pH increased, an increase in the adsorbed amount of metal of the fish bones was observed. The kinetic results of adsorption obeyed a pseudo second-order model. Freundlich and Langmuir isotherm models were applied to experimental equilibrium data of Pb (II) adsorption and the value ofRLfor Pb (II) was found to be 0.906. The thermodynamic parameters related to the adsorption process such asEa,ΔG°,ΔH°, andΔS° were calculated andEa,ΔH°, andΔS° were found to be 7.06, 46.01 kJ mol−1, and 0.141 kJ mol−1K−1for Pb (III), respectively.ΔH° values (46.01 kJmol−1) showed that the adsorption mechanism was endothermic. Weber-Morris and Urano-Tachikawa diffusion models were also applied to the experimental equilibrium data. The fish bones were effectively used as sorbent for the removal of Pb (II) ions from aqueous solutions.

Ion-selective electrodes for sodium and potassium: a new problem of what is measured and what should be reported.

1985 ◽  
Vol 31 (3) ◽  
pp. 482-485 ◽  
Author(s):  
A H Maas ◽  
O Siggaard-Andersen ◽  
H F Weisberg ◽  
W G Zijlstra
Keyword(s):  
Activity Coefficient ◽  
Theoretical Calculations ◽  
Pair Formation ◽  
Ion Selective Electrodes ◽  
Residual Liquid ◽  
Liquid Junction Potential ◽  
Liquid Junction ◽  
Normal Plasma ◽  
Sodium And Potassium ◽  
Junction Potential

Abstract For clinical purposes the activities of Na+ and K+ obtained with ion-selective electrodes in undiluted whole blood or serum should be multiplied by an appropriate factor to obtain the same values as the substance concentrations obtained by flame photometry. The factor is primarily dependent on the mass concentration of water in normal plasma divided by the molal activity coefficient of Na+ (or K+) of normal plasma. We discuss the value of the molal activity coefficient of Na+ obtained by theoretical calculations and by direct measurement. The discrepancies between theory and measurement (gamma Na+ of 0.747 and 0.73, respectively) may be due to some binding of Na+ (protein binding or ion pair formation), a small and variable residual liquid-junction potential, or certainty about the appropriate value for the ionic strength of normal plasma (0.16 mol/kg or somewhat higher).

scholarly journals Experimental Sensing and DFT Mechanism of Zn(II) Complex for Highly Sensitive and Selective Detection of Acetone

Crystals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 324
Author(s):  
Mohd. Muddassir ◽  
Mohammad Usman ◽  
Abdullah Alarifi ◽  
Mohd. Afzal ◽  
Khulud Abdullah Alshali ◽  
...  
Keyword(s):  
Hydrogen Bonding ◽  
Energy Barrier ◽  
Association Constant ◽  
Theoretical Calculations ◽  
Selective Detection ◽  
Acetone Molecule ◽  
Hydrogen Bonding Interactions ◽  
Highly Sensitive ◽  
Perchlorate Complex ◽  
Selective Sensor

In the present work, a new Zn(II) perchlorate complex with 2,2’–bipyridyl of formulation {[Zn(bipy)2(H2O)](ClO4)2} (1) was obtained and well analyzed. This chemosensor was evaluated as a selective sensor for acetone among the several different organic solvents(CH3OH, EtOH, i–PrOH, i–BuOH, CHCl3, CH2Cl2, CCl4, C6H6, C7H8, C8H10, C2H3N, C3H7NO, C4H8O2, C3H6O3) in a fluorescence turn–off response in accordance with theoretical calculations. Sensing experiments were performed at ambient temperature which shows the acetone molecule distinctly reduces transfer of energy barrier to complex 1 and hence, produces remarkable luminescent quenching. Also, the weak intermolecular hydrogen–bonding interactions thanks to the presence of various hydrogen bonding donors and acceptors, exist between ligand molecules, which were broken during fluorescence, resulting in quenching. The stoichiometry ratio and association constant were evaluated using Benesi–Hildebrand relation giving 1:1 stoichiometry between complex 1 and acetone. Additionally, DFT results can also explicate the significant response on complex 1 upon addition of acetone. This work is vital in a new loom for the detection of acetone and other ketones.

Cu(II) Ion-Selective Electrodes Based on Cu(II) Complex with Cyclized Salophen

2003 ◽  
Vol 58 (7) ◽  
pp. 658-662 ◽  
Author(s):  
Manal R. Al-Saraj ◽  
Salman M. Saadeh ◽  
Monzir S. Abdel-Latif
Keyword(s):  
Aqueous Solutions ◽  
Ion Selective Electrodes ◽  
Similar Response ◽  
Membrane Composition ◽  
Experimental Conditions ◽  
Selectivity Coefficients ◽  
Potentiometric Selectivity ◽  
Coated Disc ◽  
Coated Wire

Several versions of Cu(II) ion selective electrodes (ISE), based on cyclized N,N'-bis(salicylidene)-o-phenylenediamine (salophen) complexes with Cu(II), were fabricated for determination of Cu(II) in aqueous solutions. The response of the ISE was optimized by variation of membrane composition and evaluation of various experimental conditions. Near Nernstian slopes (~ 28-32 mV/decade) were obtained for some preparations. The linear range of the ISE ranged from 5 × 10-5 to 1 × 10-2M Cu(II). Coated-wire and coated disc ISE resulted practically in a similar response as screen printed electrodes (SPE). The potentiometric selectivity coefficients (Kij) for all electrodes were determined for Na+, NH4+, Ca2+, Mg2+, Ni2+, Pb2+, Zn2+, Cd2+, Co2+, Fe3+, Hg2+, CO32-, H2PO4-, HPO42-, SO42-, CH3COO-, Br-, I-, NO3-, and SCN-. The selectivity coefficients were in the range from 10-2 to 10-3 for all ions tested except Hg2+, I-, and to less extent Fe3+. Fabricated ISE using the Cu(II)-salophen complex are reliable and stable.

scholarly journals Removal of Cr(VI) from Aqueous Environments Using Micelle-Clay Adsorption

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Mohannad Qurie ◽  
Mustafa Khamis ◽  
Adnan Manassra ◽  
Ibrahim Ayyad ◽  
Shlomo Nir ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Continuous Flow ◽  
Contact Time ◽  
Langmuir Adsorption Isotherm ◽  
Optimal Conditions ◽  
Batch Experiments ◽  
Langmuir Adsorption ◽  
Ph Values ◽  
Aqueous Environments

Removal of Cr(VI) from aqueous solutions under different conditions was investigated using either clay (montmorillonite) or micelle-clay complex, the last obtained by adsorbing critical micelle concentration of octadecyltrimethylammonium ions onto montmorillonite. Batch experiments showed the effects of contact time, adsorbent dosage, and pH on the removal efficiency of Cr(VI) from aqueous solutions. Langmuir adsorption isotherm fitted the experimental data giving significant results. Filtration experiments using columns filled with micelle-clay complex mixed with sand were performed to assess Cr(VI) removal efficiency under continuous flow at different pH values. The micelle-clay complex used in this study was capable of removing Cr(VI) from aqueous solutions without any prior acidification of the sample. Results demonstrated that the removal effectiveness reached nearly 100% when using optimal conditions for both batch and continuous flow techniques.

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