The sorption of lead and cadmium species by clay minerals

1977 ◽  
Vol 30 (7) ◽  
pp. 1417 ◽  
Author(s):  
H Farrah ◽  
WF Pickering
Keyword(s):  
Metal Ion ◽  
Ph Value ◽  
Cadmium Ions ◽  
Ph Values ◽  
Metal Ion Adsorption ◽  
Lead And Cadmium ◽  
Anionic Complexes ◽  
The Stability ◽  
Protonated Ligand ◽  
Ligand Species

The effect of pH changes and the presence of ligands on the uptake of lead and cadmium ions by three types of clay mineral (kaolinite, illite and montmorillonite) has been investigated. ��� In the absence of ligands, metal ion adsorption increases gradually with increasing pH until a threshold pH value is exceeded, whereupon total precipitation/sorption (attributed to formation of hydroxy species) occurs. With ligands present, the threshold point tends to shift to higher pH values, the magnitude of the effect depending on the stability of the metal complex formed. Adsorption of cationic metal complexes is subject to competition from charged protonated ligand species; anionic complexes are not sorbed.

Study on Influence of Silicate Morphology Based on pH Value

2012 ◽  
Vol 454 ◽  
pp. 324-328
Author(s):  
Yan He ◽  
Ya Jing Liu ◽  
Yong Lin Cao ◽  
Li Xia Zhou
Keyword(s):  
Silicic Acid ◽  
Ph Value ◽  
Colorimetric Method ◽  
Absorption Spectrometry ◽  
Degree Of Polymerization ◽  
Raw Material ◽  
X Ray Diffraction ◽  
X Ray ◽  
Ph Values ◽  
The Stability

Infra-red absorption spectrometry, X-ray diffraction observations and characterization tests based on silicon molybdenum colorimetric method were used to investigate the optimal pH value controlling the stability of the silicic acid form. The experiment process was done by using sodium silicate as raw material. The results showed that the solution of silicate influenced the polymerization. The active silicic acid solution with a certain degree of polymerization was obtained by controlling the pH values.

scholarly journals Removal of Lead and Cadmium Ions from Aqueous Solution by Adsorption on a Low-Cost Phragmites Biomass

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 406 ◽  
Author(s):  
Abdulaziz N. Amro ◽  
Mohammad K. Abhary ◽  
Muhammad Mansoor Shaikh ◽  
Samah Ali
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
Surface Area ◽  
Metal Ion ◽  
Low Cost ◽  
Waste Water Treatment ◽  
Study Data ◽  
Small Surface ◽  
Cadmium Ions ◽  
Lead And Cadmium

In recent years, the interest in waste water treatment increased to preserve the environment. The objective of this study is the removal of lead and cadmium ions from aqueous solution by treated Phragmites biomass (TPB). TPB was characterized by using Fourier transform infrared spectroscopy (FTIR) and energy dispersive X-ray analysis (EDS) which indicates the presence of functional groups that may be responsible of metal adsorption such as hydroxyl, carbonyl, sulfonate and carboxylate. Characterization by scanning electron microscopy (SEM) and surface area analysis using the Brunauer–Emmett–Teller method (BET) illustrated that TPB is nonporous with a small surface area. The influences of various experimental factors were investigated; the proposed method recommended the extraction of Pb+2 and Cd+2 metal ions by TPB at pH 5.0. A contact time of 60 and 45 min was required for the adsorption 50 mL (50 ppm) Pb+2 and Cd+2 respectively to reach equilibrium when 0.10 g TPB was used. The optimum TPB dosage was 0.20 g for adsorption both metal ions when adsorbate solution was 50 mL (50 ppm). Particle sizes of 0.125–0.212 mm showed the best metal ion removal of both metal ions. Thermodynamic study illustrated that both metal ions correlate more with Langmuir isotherm. Furthermore, chemisorption of Pb+2 and Cd+2 on TPB was more likely according to kinetic study data.

Dyeing Properties to Wool Fabrics of Catechu Dye Purified by Micro-Filtration Membrane

2008 ◽  
Vol 12 (1) ◽  
pp. 32-38 ◽  
Author(s):  
Xiuliang Hou ◽  
Li Wei ◽  
Xinlong Zhang ◽  
Huihui Wu ◽  
Qicheng Zhou ◽  
...  
Keyword(s):  
Ph Value ◽  
Wool Fabric ◽  
Color Fastness ◽  
Color Changes ◽  
Ph Values ◽  
Filtration Membrane ◽  
Wool Fabrics ◽  
Characteristic Values ◽  
The Stability ◽  
Different Levels

Catechu liquor, which is deep brown-red in color, was purified with a micro-filtration membrane and the stability of catechu dye to different levels of temperatures and pH were investigated in this paper. The effects of the dyeing conditions on color characteristic values and color fastnesses of the dyed wool fabrics were also investigated. The results show that the liquor of catechu dye is stable at pH values of 3-7 and its color changes to a deeper brown-red when its pH value is above 8. The preferable dyeing conditions for wool fabric with refined powder catechu dye are as follows: dyeing temperature of 100±C, pH value of 6.5 for the dye bath and catechu dye of 1-4% (o.w.f). The dyed wool fabric has good color fastnesses to washing, alkali perspiration and dry rubbing. However, its color fastness rating to wet rubbing is poor, ranging from 2-3. Further research will be needed on this aspect.

scholarly journals Column Extraction and Separation of Some Metal Ions by Diethylenetriamine Polysiloxane Immobilized Ligand System

2008 ◽  
Vol 5 (1) ◽  
pp. 107-113 ◽  
Author(s):  
Nizam M. El-Ashgar
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ph Value ◽  
Good Separation ◽  
Extraction And Separation ◽  
Ph Values ◽  
Ligand System ◽  
Chromatographic Parameters ◽  
Column Extraction ◽  
Optimum Separation

An extraction chromatographic solid porous polysiloxane functionalized by chelating diethylenetriamine ligand of the general formula P-(CH2)3-NH(CH2)2NH(CH2)2NH2, (Where P represents [Si-O]nsiloxane network) has been evaluated for the separation of Co(II), Ni(II) and Cu(II) from aqueous solutions. The chromatographic parameters of the separation method have been optimized. The ligand system retained Co(II), Cu(II) and Zn(II) effectively when used as a metal ion extractant by controlling the pH value. The ligand system also shows a good separation of a mixture of metal ions Co(II), Ni(II) and Cu(II) when used as chromatographic stationary phase. The optimum separation pH values were 4.5, 4 for Co(II) and Ni(II) respectively, while a solution of 0.1 M HNO3was used to elute Cu(II). Metal ions were also preconcentrated at pH 5.5. The chemisorbed metal ions were regenerated from the solid extractant using 0.5 M HCl.

Study on Properties of PG Separated and Purified from Actinidia arguta

2013 ◽  
Vol 850-851 ◽  
pp. 1197-1201
Author(s):  
Shu Qian Li ◽  
Chang Jiang Liu ◽  
Guang Xin ◽  
Bo Zhang
Keyword(s):  
Metal Ions ◽  
Ph Value ◽  
Michaelis Constant ◽  
Actinidia Arguta ◽  
Ph Values ◽  
Key Enzyme ◽  
Optimal Reaction Temperature ◽  
The Stability ◽  
Thermo Stability ◽  
Optimal Reaction

Polygalacturonase (PG) is key enzyme for softening consenescence mechanism of fruits. In this work, Properties of PG separated and purified from wildActinidia Argutawere studied. The result shows that the optimal reaction temperature is 40°C with a high enzyme activity around 30-50°C. PG keeps a thermo stability at the temperature ranging from 30-40°C, which decreases with increasing of temperature and PG will lose all its activity under 60-70°C for 1h. The optimal reaction pH value for this enzyme is 5.5. As far as the stability in different pH values is concerned, PG is relatively stable for preservation at pH4.5-6.5.The michaelis constant for PG is 27.31. When the concentration for EDTA is higher than 2mmol/L, it is inhibitive for PG . The metal ions of K+, Ca2+, Fe2+, Fe3+, Mg2+can activate the PG enzyme to some extent, the strength of activation:Mg2+Fe3+K+Fe2+Ca2+;The metal ions of Cu2+Zn2+Mn2+Ba2+Al3+can inhibit PG enzyme to some extent, the strength of inhibition:Al3+Ba2+Mn2+Cu2+Zn2+.

The kinetics of the reaction of boric acid with salicylic acid

1977 ◽  
Vol 55 (16) ◽  
pp. 3035-3039 ◽  
Author(s):  
Alan Queen
Keyword(s):  
Salicylic Acid ◽  
Boric Acid ◽  
Kinetic Data ◽  
Similar Process ◽  
Stopped Flow ◽  
Ph Values ◽  
The Stability ◽  
Kinetics Of ◽  
Protonated Ligand ◽  
Salicylate Ion

Salicylic acid forms a 1:1 complex with boric acid, the reaction involving both the fully protonated ligand, and the salicylate ion. The kinetics of this reaction have been studied by the stopped-flow method. The stability constant for the reaction involving salicylate ion has been calculated from measurements of the absorbances of solutions at equilibrium and is the same as that obtained from the kinetic data. The kinetic results at pH values in the range 3.45–4.63 suggest that, when salicylic acid is the ligand, the complex is formed in two steps. A similar process may also occur with salicylate ions.

Study on the Effect of Amphoteric Bagasse Hemicellulose on Heavy Metal Adsorption

2011 ◽  
Vol 399-401 ◽  
pp. 1282-1288 ◽  
Author(s):  
Li Jun Wang ◽  
Xin Liang Liu ◽  
Meng Ling Weng ◽  
Shuang Xi Li ◽  
Fu Sheng Wu ◽  
...  
Keyword(s):  
Linear Model ◽  
Metal Ion ◽  
Ph Value ◽  
Absorption Capacity ◽  
Heavy Metal Adsorption ◽  
Adsorption Dynamics ◽  
Adsorption Time ◽  
Initial Concentration ◽  
Ph Values ◽  
Pseudo Second Order

In this paper, ions i.e. Cu2+, Pb2+and Cd2+ were absorbed by the amphoteric bagasse hemicelluloses, and the influences of pH value, adsorption time and the initial concentration of metal ion have been studied. The results show that the optimal adsorption pH values for Cu2+, Pb2+ and Cd2+ are 6.5, 6.0 and 7.5, respectively. The adsorption capacity to ions Cu2+, Pb2+ and Cd2+ reaches the maximum values when the adsorption time is 180 min. Net adsorption to ions Cu2+, Pb2+ and Cd2+ increases with increasing the initial concentration of the metal ions. Analysis results of adsorption dynamics show that the adsorption of Cu2+, Pb2+ and Cd2+ follows Ho 's Pseudo second-order kinetics linear model. It can be seen from the adsorption isothermal research that absorption of the amphoteric bagasse hemicelluloses to ions Cu2+, Pb2+and Cd2+ can be well described by the Langmuir isotherm linear model. Moreover, the theoretical values of the maximum absorption capacity qmax for ions Cu2+, Pb2+ and Cd2+ were determined to be 21.98 mg/g, 81.97 mg/g and 31.85 mg/g, respectively.

scholarly journals Studies on biologically important copper(II) / manganese(II) / uranyl(II) – norvaline binary complexes

2008 ◽  
Vol 27 (2) ◽  
pp. 157 ◽  
Author(s):  
Brij Bhushan Tewari
Keyword(s):  
Stability Constants ◽  
Coordination Compounds ◽  
Metal Ion ◽  
Background Electrolyte ◽  
Binary Complex ◽  
Paper Strip ◽  
Ph Values ◽  
Binary Complexes ◽  
Stability Constants Of Complexes ◽  
The Stability

In coordination compounds studies, a knowledge of the magnitude of the stability constants of complexes is necessary for preliminary quantitative treatment. Described herein is a method that involves the use of advanced ionophoretic technique for the study of the equilibria in binary complex systems in solution. This method is based upon the migration of a spot of the metal ion on a paper strip at different pH values of background electrolyte containing 0.1 M perchloric acid and 0.01 M norvaline. A graph of pH against mobility provides information about the nature of the complexation and helps in calculating stability constants. Using this method, the stability constants of binary complexes metal(II) – norvaline have been determined to be (8.11 ± 0.02, 7.03 ± 0.09); (3.77 ± 0.11, 2.39 ± 0.07) and (7.59 ± 0.05, 6.17 ± 0.04) (log K values) for Cu(II), Mn(II) and UO2(II) complexes, respectively, at 35 ºC.

scholarly journals EFFECT OF PH ON THE STABILITY OF COORDINATION COMPOUNDS OF CO(III) WITH DIAMINOETHANOL LIGANDS IN NON-AQUEOUS SOLUTIONS

2020 ◽  
Vol 2 (61) ◽  
pp. 119-127
Author(s):  
I. Kuzevanova ◽  
◽  
S. Povalchyk ◽  
A. Zulfigarov ◽  
A. Andriiko ◽  
...  
Keyword(s):  
Complex Compound ◽  
Coordination Compounds ◽  
Ph Value ◽  
Precursor Solution ◽  
Polynuclear Complex ◽  
Alkaline Solutions ◽  
Partial Hydrolysis ◽  
Ph Values ◽  
The Stability ◽  
Hydrolysis Of

Inner complex compound of cobalt(III) with diaminoethanol, [Co(DetmHdetm)], and polynuclear complex compound 2Co-Ni with diaminoethanol, [Ni(CoDetmHdetm)2](NO3)2, were synthesized. Stabilities of the obtained compounds were investigated in non-aqueous (dimethylformamide) solutions at different values of pH (from acid to alkaline). Methods of potentiometric titration and electron absorption spectra were used to determine the range of pH values where the compounds do not decompose. As a result of these studies, we found that at the upper value of pH=7, the coordination surrounding of the metals (Co(III), Ni(II)) does not change. When the pH value becomes lower than 7 (with adding HCl acide), the inner complex of Co(III) begins to decompose. The ligand H2detm is replaced by Cland partial protonization of diethanolamine occurs. Also, transformation of N,Ncis isomer of inner complex compound of cobalt(III) to N,N-trans isomer takes place, thus reducing the symmetry of the complex. As for the polynuclear complex compound 2Co-Ni, when pH value becomes lower than 7, molecules of solvent begin to react with the products of partially destroyed complex. As a result, new complex compound is formed with the increase of coordination number of nickel(II) from 4 to 6. However, in alkaline solutions where pH values are up to 10, the heterometal complex compound of 2Co-Ni remains stable. Only partial hydrolysis of the solvent occurs in these conditions. The schemes of transformations of [Co(DetmHdetm)] and [Ni(CoDetmHdetm)2](NO3)2 occuring in non-aqueous (dimethylformamide) solutions at different values of pH (from acid to alkaline) are presented in the paper. The results of this study can be used for the preparation of precursor solution for the technology of catalytic materials production. Evidently, the range of pH from 7 to 10 must be maintained in order to avoid the contamination of the final products by the decomposed wastes of complexes and solvent.

Sugar hydrolysis and colour formation in processing

2020 ◽  
pp. 540-548
Author(s):  
Jan Maarten de Bruijn
Keyword(s):  
Ph Value ◽  
Cost Effective ◽  
Production Costs ◽  
Ph Values ◽  
Technological Impact ◽  
The Stability ◽  
The Cost ◽  
Required Quality ◽  
White Sugar ◽  
Sugar Hydrolysis

The stability of the sucrose molecule throughout processing is of the utmost importance, because in principle any sugar loss will increase the production costs per tonne of the obtained white sugar. Colour in processing is an important technological parameter too, since only an adequate colour control in processing allows the cost-effective production of white sugar crystals of the required quality. For process control of both sugar hydrolysis and colour formation it is necessary to understand the effect of pH value, temperature and retention time on these phenomena. This paper will describe the possible causes of sugar hydrolysis and colour, as well as how to control pH values and temperature in processing in order to limit the technological impact of both reactions in which invert sugar plays a central role.

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