scholarly journals Boron removal from aqueous solutions by a polyethylenimine-epichlorohydrin resin

2018 ◽  
Vol 83 (2) ◽  
pp. 251-264 ◽  
Author(s):  
Sofia Sarri ◽  
Panagiotis Misaelides ◽  
Dimitrios Zamboulis ◽  
Jolanta Warchoł
Keyword(s):  
Aqueous Solutions ◽  
Boron Concentration ◽  
Kinetic Studies ◽  
Alkaline Solutions ◽  
Competitive Sorption ◽  
Boron Removal ◽  
Boron Uptake ◽  
Acidic Solutions ◽  
Ph Values ◽  
Batch Technique

The use of a polyethylenimine?epichlorohydrin resin for the boron removal from aqueous solutions (boron concentration: 100?5000 mg L-1) of non-adjusted and pre-adjusted pH (pHnat, pHinit 8.0, 9.0 and 10.0) aqueous solutions was investigated using a batch technique. The boron concentration in the solutions after sorption was determined photometrically. The results indicated that the pH-dependent boron uptake was related to the protonation/deprotonation of the surface functional groups of the resin and to the boron speciation in solutions of different pH values. The maximum boron sorption capacity observed in solutions of pH 9.0 was 55 mg g-1 exceeding the majority of other commercial or alternative sorbents. Five empirical adsorption equations (Freundlich, Langmuir, Redlich?Peterson, Langmuir?Freundlich and Toth) were applied to the modelling of the boron adsorption equilibrium. The modelling results identified the homogenous boron sorption from acidic and heterogeneous from alkaline solutions. At alkaline pH, the system non-ideality can originate either from the different binding mechanism or from the competitive sorption of different boron species. The homogenous type boron sorption from acidic solutions was further confirmed by kinetic studies

Investigation of Cu(II) adsorption from aqueous solutions by NKF-6 zeolite

2011 ◽  
Vol 63 (3) ◽  
pp. 395-402 ◽  
Author(s):  
H. Zhang ◽  
D. Zhao ◽  
L. Chen ◽  
X. J. Yu
Keyword(s):  
Aqueous Solutions ◽  
Outer Sphere ◽  
Low Ph ◽  
Ambient Conditions ◽  
Temperature Dependent ◽  
Ph Values ◽  
Batch Technique ◽  
Negative Effect ◽  
High Level ◽  
Positive Effect

Adsorption of Cu(II) from aqueous solutions using NKF-6 zeolite was investigated by batch technique under ambient conditions. The adsorption was investigated as a function of pH, ionic strength, fulvic acid (FA), foreign ions and temperature. The results indicated that the adsorption of Cu(II) on NKF-6 zeolite gradually increases from 0 to 90% with increasing pH at pH<6.5, and maintains high level at pH>6.5. Outer-sphere complexation or ion exchange may be the main adsorption mechanism of Cu(II) to NKF-6 zeolite at low pH values, whereas the adsorption of Cu(II) at pH>6.5 is mainly dominated by inner-sphere complexation or precipitation. A positive effect of FA on Cu(II) adsorption onto NKF-6 zeolite is observed at low pH values, while a negative effect of FA is observed at high pH values. The thermodynamic parameters (i.e., ΔH0, ΔS0 and ΔG0) for the adsorption of Cu(II) were determined from the temperature dependent isotherms at 20, 40 and 60°C, respectively, and the results indicated that the adsorption reaction is favoured at low temperature. The results suggested that the adsorption process of Cu(II) on NKF-6 zeolite is spontaneous and exothermic.

Boron Removal from Water Using Takovite: Adsorption vs. Anion Exchange

2013 ◽  
Vol 781-784 ◽  
pp. 2150-2156 ◽  
Author(s):  
Yao Wu Cao ◽  
Qing Hai Guo
Keyword(s):  
Anion Exchange ◽  
Boron Concentration ◽  
Boron Removal ◽  
Boron Uptake ◽  
X Ray Diffraction ◽  
Structural Restoration ◽  
Experimental Conditions ◽  
Sorption Data ◽  
Freundlich Model ◽  
Higher Temperature

Takovite, a kind of hydrotalcite-like compounds (HTlcs), was used for boron removal from water. It was prepared by coprecipitation method and characterized by X-ray diffraction technique (XRD). The equilibrium time of boron sorption by takovite as well as its boron uptake capacities was determined by the reaction kinetic experiments and isotherm sorption experiments. The effects of experimental conditions on boron removal efficiency were also evaluated. Generally, the boron uptake by takovites increases with increasing initial boron concentration in solution. The isotherm sorption data match well with the Freundlich model, indicating that the anion exchange contributes a lot to solution deboronation. Moreover, at higher temperature, greater boron removal by takovite was observed. As compared to calcined takovite, uncalcined takovite has better performance in terms of boron uptake, since the structural restoration of calcined takovite didnt happen during its contact with boron-containing solution, which is quite different from the behavior of other HTlcs as reported.

Study on Stability of AgI/TiO2 Visible Light Photocatalysts in Solutions of Various pH Values

2011 ◽  
Vol 399-401 ◽  
pp. 1272-1275
Author(s):  
Lu Feng ◽  
Ke Feng He ◽  
Wan Ping Chen
Keyword(s):  
Visible Light ◽  
Absorption Edge ◽  
Ph Value ◽  
Alkaline Treatment ◽  
Alkaline Solutions ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Solutions ◽  
Ph Values ◽  
Vis Spectroscopy

Nanostructured AgI/TiO2 photocatalysts exhibit highly efficient visible light photocatalytic activity. Though there have been extensive investigations on AgI/TiO2 photocatalysts, study on their stablity is still very limited. So in this paper, such a study is designed and conducted. AgI/TiO2 nanostructured photocatalysts were prepared and separately immersed in HCl solutions, DI water and NaOH solutions with pH value of 0, 4, 7, 10 and 14, respectively. X-ray diffraction and diffusive reflectance UV-vis spectroscopy analyses reveal that the immersion in acidic solutions led to the formation of AgCl and a blue shifting to 450nm for the absorption edge of AgI/TiO2, while the alkaline treatment had no significant effect on the composite structure of AgI/TiO2 or on the UV-vis absorption edge. Photocatalytic tests show that immersion in acidic solutions had more significant influence on AgI/TiO2 photocatalytic degradation of methyl orange (MO). At pH = 4, photocatalytic efficiency was dropped nearly 30%. At pH = 10, no significant change was observed. AgI/TiO2 nanostructured photocatalysts have thus been found to display a higher stability in alkaline solutions than in acidic solutions.

The Photolysis of Aqueous-Solutions of Potassium Hexacyanoferrate(III)

1986 ◽  
Vol 39 (9) ◽  
pp. 1411 ◽  
Author(s):  
MW Fuller ◽  
KMF Lebrocq ◽  
E Leslie ◽  
IR Wilson
Keyword(s):  
Aqueous Solutions ◽  
Quantum Yields ◽  
Alkaline Solutions ◽  
Potassium Hexacyanoferrate ◽  
Thermal Reactions ◽  
Acidic Solutions

The photolysis of aqueous solutions of potassium hexacyanoferrate(III) at 254 and 366 nm forms aqua- or hydroxo-pentacyanoferrate(III) in both acidic and alkaline solutions, with quantum yields between 0.02 and 0.06. Subsequent thermal reactions form the decacyanodiferrate(III) and/or decacyanodiferrate(III,II) species, especially in weakly acidic solutions, and, in alkaline solutions, may precipitate hydrated iron(III) oxides.

Removal of thorium(IV) from aqueous solutions by natural sepiolite

2017 ◽  
Vol 105 (3) ◽  
Author(s):  
Kadriye Esen Erden ◽  
Ramazan Donat
Keyword(s):  
Aqueous Solutions ◽  
Thermodynamic Data ◽  
Adsorption Process ◽  
Adsorption Efficiency ◽  
Optimum Conditions ◽  
High Adsorption ◽  
Ph Values ◽  
Batch Technique

AbstractNatural sepiolite has been tested as a potential sorbent for the removal of Th(IV) from aqueous solutions by batch technique. Effects of various parameters on the adsorption process have been investigated. Under optimum conditions, Th(IV) was adsorbed with high adsorption efficiency. The results indicated that sorption of Th(IV) on sepiolite was strongly affected by pH values and temperature. The adsorption patterns of thorium on the sepiolite adsorbent followed the Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms. The thermodynamic data (Δ

scholarly journals Influence of pH on the Electropolymerisation of 2-Aminophenol and 2-Aminobenzyl Alcohol

2015 ◽  
Vol 18 (1) ◽  
pp. 037-041
Author(s):  
Ahmad S. Barham
Keyword(s):  
Aqueous Solutions ◽  
Benzene Ring ◽  
Polymer Films ◽  
Resonance Effect ◽  
Microelectrode Arrays ◽  
Hydroxyl Group ◽  
Amine Group ◽  
Acidic Solutions ◽  
Ph Values ◽  
Influence Of Ph

The electrochemical oxidation and polymerisation of 2-aminophenol and 2-aminobenzyl alcohol in aqueous solutions of different pH values has been studied. Polymer films of the studied monomers on gold electrodes were synthesized. The behaviour of both monomers is quite different, illustrating the resonance effect of the hydroxyl group being bound directly to the benzene ring for 2-aminophenol. For each compound it is shown that oxidation in acidic solutions is most difficult due to the protonation of the amine group. These polymer films can be used for applications such as corrosion protection and as structures from which textured electrodes, microelectrode arrays for example, can be generated.

HPLC Analysis of Oxytetracycline Residues in Honey

1986 ◽  
Vol 49 (5) ◽  
pp. 383-388 ◽  
Author(s):  
PETER SPORNS ◽  
SUET KWAN ◽  
LAWRENCE A. ROTH
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Aqueous Solutions ◽  
High Performance ◽  
Hplc Analysis ◽  
Extraction Procedure ◽  
Hplc Method ◽  
Limits Of Detection ◽  
Ph Values ◽  
Double Extraction

Oxytetracycline (OTC), also known commercially as Terramycin, was determined to be more stable in honey than in buffered aqueous solutions at similar pH values and temperatures. A rapid high performance liquid chromatography (HPLC) method was developed to detect and quantitate OTC using a 1:1 dilution (wt/wt) of honey samples in water. Using 355 nm as the wavelength of detection, amounts as low as 0.5 μg/ml could be detected in the above solution. The limits of detection were lowered considerably by a double extraction procedure.

scholarly journals Metal–organic frameworks (MOFs) as highly efficient agents for boron removal and boron isotope separation

RSC Advances ◽  
2017 ◽  
Vol 7 (26) ◽  
pp. 16022-16026 ◽  
Author(s):  
Jiafei Lyu ◽  
Hongxu Liu ◽  
Jingshuang Zhang ◽  
Zhouliangzi Zeng ◽  
Peng Bai ◽  
...  
Keyword(s):  
Separation Factor ◽  
Isotope Separation ◽  
Metal Organic Frameworks ◽  
Boron Isotope ◽  
Boron Removal ◽  
Boron Uptake ◽  
Highly Efficient ◽  
Metal Organic ◽  
High Boron

A variety of MOFs were observed with ZIF-8, to our knowledge, showing the highest boron uptake and MIL-101(Cr) with an unprecedentedly high boron isotope separation factor.

Sign in / Sign up

Export Citation Format

Share Document