scholarly journals An Investigation into the Adsorption of Aniline from Aqueous Solution Using H-Beta Zeolites and Copper-Exchanged Beta Zeolites

2005 ◽  
Vol 23 (3) ◽  
pp. 255-266 ◽  
Author(s):  
J. O'Brien ◽  
T. Curtin ◽  
T.F. O'Dwyer
Keyword(s):  
Aqueous Solution ◽  
Adsorption Process ◽  
Zeolite Beta ◽  
Langmuir Model ◽  
Beta Zeolite ◽  
Copper Leaching ◽  
Beta Zeolites ◽  
The Stability ◽  
Ph Range ◽  
Adsorbent Materials

Zeolite beta, a large-pore zeolite, was investigated in this study with a view to examining it as a potential adsorbent for the removal of aniline from aqueous solutions. Two different metal-loaded zeolites were prepared by exchanging H-beta zeolite (SiO2/Al2O3 = 75:1) with copper. The influence of exchanged copper on the uptake level was assessed. The effect of varying the silica-to-alumina ratio of the H-beta zeolite on the aniline uptake level was also examined, using three different H-beta zeolites with ratios of 25:1, 75:1 and 150:1 as adsorbents. The sorption experiments indicated an uptake level of ca. 110–120 mg/g for each zeolite and this level was also adsorbed by the copper-modified H-beta zeolites (SiO2/Al2O3 = 75:1). In all cases, the adsorption process followed the Langmuir model for adsorption and the level of aniline adsorbed was largely unaffected by a change in temperature or the presence of extra framework copper. The stability of the exchanged copper on these zeolites was then examined by measuring the quantity of copper leached from each zeolite into solution as a function of pH. Minimum copper leaching was observed in the pH range 5–11. This provided a stable pH working range for the adsorbent materials.

REMOVAL OF HEAVY METAL Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II) IONS FROM AQUEOUS SOLUTION BY MENTHA PIPERITA EXTRACT

2020 ◽  
pp. 15-20
Author(s):  
Ersin Yucel ◽  
Mine Yucel
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
High Efficiency ◽  
Correlation Coefficients ◽  
Langmuir Model ◽  
Mentha Piperita ◽  
Freundlich Model ◽  
Biosorption Capacity ◽  
Peppermint Extract ◽  
The Stability

In this study, the usage of the peppermint (Mentha piperita) for extracting the metal ions [Mg (II), Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II)] that exist at water was investigated. In order to analyze the stability properties, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used at removing the metal ions and the highest correlation coefficients (R2) were obtained at Langmuir isotherm. Therefore, it is seen that the Langmuir model is more proper than the Freundlich model. However, it was found that the correlation coefficients of removing Ni and Cd is higher at Freundlich model than Langmuir and low at Dubinin-Radushkevich isotherm. It is established that the biosorption amount increase depends on the increase of biosorbent and it can be achieved high efficiency (95%) even with small amount (0.6 mg, peppermint extract) at lead ions. It is also determined that the peppermint extracted that is used at this study shows high biosorption capacity for metal ions and can be used for immobilization of metals from polluted areas.

Schiff base equilibria. II. Beryllium complexes of N-n-butylsalicylideneimine and the hydrolysis of the Be2+ ion

1965 ◽  
Vol 18 (5) ◽  
pp. 651 ◽  
Author(s):  
RW Green ◽  
PW Alexander
Keyword(s):  
Aqueous Solution ◽  
Schiff Base ◽  
Complex Formation ◽  
Distribution Coefficient ◽  
Dilute Aqueous Solution ◽  
The Stability ◽  
Ph Range ◽  
Hydrolysis Of ◽  
Beryllium Complexes ◽  
Equilibria In Aqueous Solution

The Schiff base, N-n-butylsalicylideneimine, extracts more than 99.8% beryllium into toluene from dilute aqueous solution. The distribution of beryllium has been studied in the pH range 5-13 and is discussed in terms of the several complex equilibria in aqueous solution. The stability constants of the complexes formed between beryllium and the Schiff base are log β1 11.1 and log β2 20.4, and the distribution coefficient of the bis complex is 550. Over most of the pH range, hydrolysis of the Be2+ ion competes with complex formation and provides a means of measuring the hydrolysis constants. They are for the reactions: Be(H2O)42+ ↔ 2H+ + Be(H2O)2(OH)2, log*β2 - 13.65; Be(H2O)42+ ↔ 3H+ + Be(H2O)(OH)3-, log*β3 -24.11.

scholarly journals Preparation, Characterization and Adsorption Potential of Grainy Halloysite-CNT Composites for Anthracene Removal from Aqueous Solution

Nanomaterials ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 890 ◽  
Author(s):  
Gabriela Kamińska ◽  
Mariusz Dudziak ◽  
Edyta Kudlek ◽  
Jolanta Bohdziewicz
Keyword(s):  
Carbon Nanotubes ◽  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Contact Time ◽  
Adsorption Process ◽  
Heating Temperature ◽  
Langmuir Model ◽  
Adsorption Potential ◽  
Adsorption Sites ◽  
Enhanced Adsorption

Grainy Hal-CNT composites were prepared from powder halloysite nanoclay (Hal) and carbon nanotubes (CNTs). The effect of the amount and type of CNTs, as well as calcination temperature on morphology and properties of Hal-CNT composites and their adsorption capacity of anthracene (ANT), were studied. The surface topography of granules was heterogenous, with cracks and channels created during granulation of powder clay and CNTs. In FTIR, spectra were exhibited only in the bands arising from halloysite, due to its dominance in the granules. The increase in the heating temperature to 550 °C resulted in mesoporosity/macroporosity of the granules, the lowest specific surface area (SSA) and poorest adsorption potential. Overall, SSA of all Hal-CNT composites were higher than raw Hal, and by itself, heated halloysite. The larger amount of CNTs enhanced adsorption kinetics due to the more external adsorption sites. The equilibrium was established with the contact time of approximately 30 min for the sample Hal-SWCNT 85:15, while the samples with loading 96:4, it was 60–90 min. Adsorption isotherms for ANT showed L1 type, which is representative for the sorbents with limited adsorption capacity. The Langmuir model described the adsorption process, suggesting a monolayer covering. The sample Hal-SWCNT 85:15 exhibited the highest adsorption capacity of ANT, due to its highest SSA and microporous character.

Impact of inorganic buffering ions on the stability of Fe(vi) in aqueous solution: role of the carbonate ion

2016 ◽  
Vol 18 (6) ◽  
pp. 4415-4422 ◽  
Author(s):  
Michal Kolář ◽  
Petr Novák ◽  
Karolína M. Šišková ◽  
Libor Machala ◽  
Ondřej Malina ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Carbonate Ion ◽  
The Stability ◽  
Ph Range

The study presents a systematic kinetics investigation of the decay of ferrate(vi) in the presence of inorganic buffering ions (borate, phosphate, and carbonate) at a pH range from 6.0 to 9.0.

scholarly journals A cobalt-organic framework with sensitive detection of Fe3+, Cr2O72–, and CrO42– ions in water

2021 ◽  
Author(s):  
Zhen Zhang ◽  
Han-Xu Sun ◽  
Shi-Fen Li ◽  
Rui-Dong Wang ◽  
Lin Du ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Metal Organic Framework ◽  
Surface Characteristics ◽  
The Novel ◽  
Elemental Analyses ◽  
Metal Organic ◽  
Crystal Structural ◽  
The Stability ◽  
Ph Range ◽  
Organic Framework

Abstract A six-coordinated 3D metal–organic framework (MOF), namely, [Co(BPDC)(3-bpdb)(H2O)2]n (1) (H2BPDC = 4,4′-biphenyldicarboxylic acid, 3-bpdb = 1,4-bis(3-pyridyl)-2,3-diaza-1,3-butadiene) was purposefully constructed and characterized by single-crystal XRD, IR, elemental analyses, PXRD, SEM, and TGA. Crystal structural analysis revealed that the complex consists of a cds-type three-fold interpenetrated framework. Hirshfeld surface analysis yielded details of the surface characteristics of 1. Significant O−H···O hydrogen bonding interactions, which could promote the stability of the framework, were found is extremely stable in aqueous solution and can resist acids and bases over an extensive pH range of 2 - 13. 1 shows brilliant fluorescent emission in the solid state and in aqueous solution. Fluorescence titration, cyclic, and anti-interference experiments demonstrated that 1 is an excellent probe for Fe3+, CrO42‒ and Cr2O72‒ in water. The Ksv values of 1 for Fe3+, CrO42‒, and Cr2O72‒, which were as high as 1.06 × 104 M−1, 1.50 × 104 M−1, and 1.16 × 104 M−1, respectively, were comparable with those of other sensors. The quenching mechanism of the novel probe was subsequently explained.

scholarly journals Reductive Adsorption of Chromium(VI) with Activated Carbon

2021 ◽  
Vol 333 ◽  
pp. 04004
Author(s):  
Anh Viet Hoang ◽  
Ya Wen Chen ◽  
Ya-Fen Wang ◽  
Syouhei Nishihama ◽  
Kazuharu Yoshizuka
Keyword(s):  
Aqueous Solution ◽  
Activated Carbon ◽  
Contact Time ◽  
Adsorption Process ◽  
Acidic Ph ◽  
High Adsorption ◽  
Varying Parameters ◽  
High Ph ◽  
Chromium Vi ◽  
Ph Range

Reductive adsorption of chromium (Cr) has been investigated, employing coal-based activated carbon with batchwise study. The adsorption was carried out by varying parameters such as pH of the aqueous solution and contact time. Cr(III) was hardly adsorbed on activated carbon, and it was precipitated at high pH region. High adsorption amounts of Cr(VI) was obtained at pH range 4.5 – 5.5. In the adsorption process, reduction of Cr(VI) to Cr(III) was occurred at especially acidic pH region, and thus most of Cr remained in the aqueous solution in this pH region was Cr(III).

The Stability and Structure of Complex Species Formed in Equilibrium Reactions of Diethyltin(IV) with N-D-Gluconylamino Acids in Aqueous Solution

1995 ◽  
Vol 50 (4) ◽  
pp. 515-523 ◽  
Author(s):  
B. Gyurcsik ◽  
N. Buzás ◽  
T. Gajda ◽  
L. Nagy ◽  
E. Kuzmann ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Amino Acid ◽  
Water Soluble ◽  
Complex Formation Equilibria ◽  
Complex Species ◽  
Carboxylate Oxygen ◽  
Equilibrium Reactions ◽  
Formation Equilibria ◽  
The Stability ◽  
Ph Range

Complex formation equilibria of diethyltin(IV) with five N-D-gluconylamino acids in aqueous solution (I = 0.1 M, NaClO4) were studied and the stabilities of the species were determined by potentiometric titrations. Diethyltin(IV) complexes of α-amino acid derivatives are water-soluble in the physiological pH range, while in the presence of N-D-gluconyl-β-alanine a precipitate is formed, which dissolves with increasing pH. 13C NMR measurements showed that in the N-D-gluconyl-α-amino acid complexes the ligand is coordinated through its deprotonated carboxylate oxygen, amide nitrogen and C(2)-hydroxy group, while for the soluble N-D-gluconyl-β-alanine complex the ligand is coordinated via the deprotonated carboxylate and C(3)-, C(4)-, C(5)-hydroxy groups. Mössbauer measurements reflected the geometry of the complexes formed.

scholarly journals Effects of pH on the stability of cyanidin and cyanidin 3-O-β-glucopyranoside in aqueous solution

2015 ◽  
Vol 69 (5) ◽  
pp. 511-522 ◽  
Author(s):  
Violeta Rakic ◽  
Mihaela Skrt ◽  
Milena Miljkovic ◽  
Danijela Kostic ◽  
Dusan Sokolovic ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Visible Range ◽  
Colour Intensity ◽  
Colour Variation ◽  
Acidic Solutions ◽  
Absorbance Maximum ◽  
Ph Values ◽  
Effects Of Ph ◽  
The Stability ◽  
Ph Range

The colour variation, colour intensity and stability at various pH values (2.0, 4.0, 7.0 and 9.0) of cyanidin 3-O-?-glucopyranoside (Cy3Glc) and its aglycone cyanidin was investigated during a period of 8 hours storage at 25?C. Our data showed that pH of aqueous solution had impact on spectroscopic profile of cyanidin and Cy3Glc. Beginning with the most acidic solutions, increasing the pH induce bathochromic shifts of absorbance maximum in the visible range for all examined pH values (with the exception pH 4.0 for cyanidin), while the presence of the 3-glucosidic substitution induce hypsochromic shift. Compared to cyanidin, Cy3Glc has higher colour intensity and higher stability in the whole pH range, except at pH 7.0. The 3-glucosidic substitution influences on the colour intensity of Cy3Glc in the alkaline region. After 8-hour incubation of Cy3Glc and cyanidin at pH 2.0 and 25 ?C, 99% of Cy3Glc and only 27% of cyanidin remained unchanged.

scholarly journals Utilisation of a Mesoporous Silicate Material for the Removal of Quaternary Ammonium Hydroxides (QAHs) from Aqueous Solution

2002 ◽  
Vol 20 (3) ◽  
pp. 261-267 ◽  
Author(s):  
Brian P. Kelleher ◽  
Aidan M. Doyle ◽  
Benjamin K. Hodnett ◽  
Thomas F. O'Dwyer
Keyword(s):  
Aqueous Solution ◽  
Quaternary Ammonium ◽  
Pore Volume ◽  
Adsorption Process ◽  
Molecular Size ◽  
Ammonium Hydroxide ◽  
Langmuir Model ◽  
Silicate Material ◽  
Mesoporous Silicate ◽  
Cubic Mesoporous

A cubic mesoporous silicate (CMS) was prepared, characterised and assessed as an adsorbent for quaternary ammonium hydroxides (QAHs) from aqueous solution. The adsorption process was studied as a function of molecular size and CMS pore volume. Sorption closely followed the Langmuir model. A comparison of the CMS pore volume and the volume of the sorbed molecules suggested that monolayer sorption occurred and that the number of molecules sorbed was a function of the size of the quaternary ammonium hydroxide molecule and the threshold area capable of being occupied by this molecule.

Removal of Methyl Red from Aqueous Solution by Adsorption onto Mg-Al HTLc

2013 ◽  
Vol 750-752 ◽  
pp. 1426-1429
Author(s):  
Yun Bo Zang
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Contact Time ◽  
Adsorption Process ◽  
Bulk Solution ◽  
Methyl Red ◽  
Initial Ph ◽  
Pseudo Second Order ◽  
Ph Range ◽  
Percent Removal

In this study, removal of Methyl Red from aqueous solutions by synthetic Mg-Al-HTlc was investigated as a function of contact time, pH and temperature. It is found that HTlc could reduced Methyl Red concentration effectively. The kinetic process which reached equilibrium at about 2h can be fitted by pseudo-second order kinetics. The percent removal of MR by the HTlc was dependent on the initial pH of bulk solution. There was no much changes in amount of adsorption in the initial pH range of 6-8, while it reached maxium at about of 9. The adsorption process was endothermic.

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