Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb DITHIZON and Ostsorb SALICYL

1994 ◽  
Vol 59 (6) ◽  
pp. 1319-1325 ◽  
Author(s):  
Ladislav Svoboda ◽  
Stanislav Jech
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Metal Concentrations ◽  
Cadmium And Lead

The pH and I (ionic strength) dependences of exchange capacity of chelating ion exchangers Ostsorb based on spherical cellulose modified with functional groups of dithizone and salicylic acid have been studied in the sorption of Pb(II) and Cd(II) ions. The cellulosic selective sorbents Ostsorb DITHIZON and Ostsorb SALICYL can be used for sorption of Pb(II) and Cd(II) ions from aqueous solutions of I = 0 - 1 mol l-1 (Pb) and I = 0 - 5 mol l-1 (Cd); the dithizone ion exchanger retains both metals most effectively at pH 7 - 8, the salicyl ion exchanger at pH 5.5 - 6.5 (Pb) or pH 4 - 9 (Cd). Because of the formation of precipitates of hydrolytic products of the two metals in neutral and alkaline media, it is suitable to carry out the sorption in media of mild acidity if possible, particularly so at the metal concentrations above 1 mg l-1. Increasing ionic strength affects the exchange capacity for both metals in a negative way.

Sorption of Cadmium and Lead by Chelating Ion Exchangers Ostsorb OXIN, Ostsorb DETA, and Ostsorb DTTA

1994 ◽  
Vol 59 (6) ◽  
pp. 1311-1318 ◽  
Author(s):  
Ladislav Svoboda ◽  
Petr Vořechovský
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Sodium Perchlorate ◽  
Exchange Capacity ◽  
Chloride Ions ◽  
Point Of View ◽  
Alkaline Media ◽  
Ion Exchangers ◽  
Acidic Media ◽  
Cadmium And Lead

The properties of cellulose chelating ion exchangers Ostsorb have been studied in the sorption of cadmium and lead from aqueous solutions. The Cd(II) and Pb(II) ions are trapped by the Ostsorb OXIN and Ostsorb DETA ion exchangers most effectively in neutral and alkaline media but at these conditions formation of stable hydrolytic products of both metals competes with the exchange equilibria. From this point of view, Ostsorb DTTA appears to be a more suitable sorbent since it traps the Pb(II) and Cd(II) ions in acidic media already. Chloride ions interfere with the sorption of the two metals by Ostsorb DTTA whereas the ionic strength adjusted by the addition of sodium perchlorate does not affect the exchange capacity of this ion exchanger.

Effect of Crosslinking Time on Ion Exchange Capacity of Polystyrene Nanofiber Ion Exchangers

2012 ◽  
Vol 506 ◽  
pp. 437-440 ◽  
Author(s):  
T. Nitanan ◽  
Prasert Akkaramongkolporn ◽  
Theerasak Rojanarata ◽  
Tanasait Ngawhirunpat ◽  
Praneet Opanasopit
Keyword(s):  
Sulfuric Acid ◽  
Controlled Release ◽  
Ion Exchange ◽  
Cation Exchange ◽  
Functional Groups ◽  
Crosslinking Agent ◽  
Exchange Capacity ◽  
Ion Exchanger ◽  
Ion Exchangers ◽  
Ion Exchange Capacity

In this study, polystyrene nanofiber ion exchangers (PSNIE) were successfully prepared by a new method comprising of electrospinning and the subsequent crosslinking with formaldehyde and sulfonation in sulfuric acid to create the cation exchange functionality on the fibers surfaces. The PS solution at 15% w/v in dimethylacetamide (DMAc) produced the smallest PS nanofibers (399±38 nm) with good performance. The degree of crosslink and ion exchange capacity (IEC) of PSNIE depended upon the crosslinking time. The longer crosslinking time caused the greater crosslinked PS fibers. At the longest crosslinking time of 75 min, the remaining crosslinked PS fibers in dichloromethane were 94.12%; whereas, the starting fibers completely dissolved. This crosslinking agent (e.g. formaldehyde) might introduce methylene bridges in addition to sulfone bridges into the fibers. However, IEC decreased as crosslinking time increased, probably due to the difficulty of sulfonic functional groups to react with crosslinked PS fibers. The PSNIE crosslinked for 10 min showed the maximum IEC of 2.86 meq/g-dry-PSNIE, and the diameter of the PSNIE after sulfonation increased to 450-460 nm. Since cationic drug could be loaded onto this novel PSNIE, this nanofiber ion exchanger may be applied for controlled release delivery.

Sorption of Lead by the Selective Ion Exchanger Ostsorb DETA

1992 ◽  
Vol 57 (7) ◽  
pp. 1393-1404 ◽  
Author(s):  
Ladislav Svoboda ◽  
Jan Uhlíř ◽  
Zdeněk Uhlíř
Keyword(s):  
Phosphoric Acid ◽  
Aqueous Solutions ◽  
Functional Groups ◽  
Ion Exchanger ◽  
Preconcentration Procedure ◽  
Bead Cellulose

The properties of Ostsorb DETA, a selective ion exchanger based on modified bead cellulose with chemically bonded diethylenetriamine functional groups, were studied, and its applicability to the preconcentration of trace amounts of lead from aqueous solutions was verified. The conditions of the preconcentration procedure in the column and batch modes were optimized for this purpose. The results obtained were applied to the determination of lead in phosphoric acid.

The Electroreduction of Periodate Anion in Alkaline Media

1971 ◽  
Vol 49 (16) ◽  
pp. 2657-2663 ◽  
Author(s):  
W. R. Fawcett ◽  
Y. C. Kuo Lee
Keyword(s):  
Ionic Strength ◽  
Aqueous Solutions ◽  
Double Layer ◽  
Mercury Electrode ◽  
Electrode Reaction ◽  
Alkaline Media ◽  
Dropping Mercury Electrode ◽  
Ph Range ◽  
Theoretical Developments

The electroreduction of periodate anion was studied at a dropping mercury electrode in aqueous solutions in the pH range 11–13.3 where the process is markedly affected by the double layer. The electrode reaction was found to be complex, its mechanism depending on both pH and ionic strength. The effects of the double layer on the component reactions are discussed with respect to current theoretical developments.

Solvent Extraction of Mono(salicylato)beryllium, and the pH Titration of the System Beryllium-Salicylic Acid

1962 ◽  
Vol 15 (2) ◽  
pp. 218 ◽  
Author(s):  
Bruin HJ de ◽  
D Kairaitis ◽  
L Szego
Keyword(s):  
Salicylic Acid ◽  
Ionic Strength ◽  
Solvent Extraction ◽  
Aqueous Solutions ◽  
Distribution Ratio ◽  
Free Ligand ◽  
Ph Titration ◽  
Maximum Value ◽  
The Stability ◽  
Beryllium Complexes

It has been shown that a salicylatoberyllium complex can be extracted from aqueous solutions by aliphatic alcohols. The distribution ratio is a symmetrical function of the logarithm of the free ligand concentration and passes through a maximum value ; the stability constants of the mono- and bis(salicylato)beryllium complexes have been determined from the data for points of equal extraction. The values obtained in this way are β1 = 4.1 x 1012 and β2 = 4.3 x 1022, in an ionic strength of 0.15. They agree fairly well with those obtained by pH-titration procedures, which are β1 = 6.1 x 1012 and β2 =7 x 1022.

Sorption of Lead and Cadmium on Ostsorb P and Ostsorb SA-5 Cellulose Sorbents

1992 ◽  
Vol 57 (10) ◽  
pp. 2089-2094 ◽  
Author(s):  
Ladislav Svoboda ◽  
Leona Čáňová
Keyword(s):  
Ionic Strength ◽  
Functional Groups ◽  
Cation Exchanger ◽  
Exchange Capacity ◽  
Low Ph ◽  
The Other ◽  
Ph Values ◽  
Lead And Cadmium ◽  
Acid Fragment ◽  
Bead Cellulose

The effect of pH and ionic strength on the exchange capacity of sorbents based on modified bead cellulose was examined for the sorption of Pb2+ and Cd2+ ions. Ion exchange of these cations in aqueous solutions is nonselective on Ostsorb SA-5, which is cellulose containing functional groups based on H-acid. The medium acidic Ostsorb P cation exchanger with functional groups formed by the phosphoric acid fragment, on the other hand, sorbs lead, and to a lesser extent also cadmium, also at high ionic strengths of the medium even at low pH values.

Organic ion exchangers with enhanced catalytic activity

1982 ◽  
Vol 47 (6) ◽  
pp. 1613-1620
Author(s):  
Zdeněk Prokop ◽  
Karel Setínek
Keyword(s):  
Catalytic Activity ◽  
Functional Groups ◽  
Ion Exchanger ◽  
Ion Exchangers ◽  
Styrene Divinylbenzene

Several methods aimed at increasing the catalytic activity of the sulphonated styrene-divinylbenzene macroporous ion exchanger Wofatit OK 80 have been tested. The activity of the prepared ion exchanger catalysts has been examined in three reactions of different type which allowed to examine the effect of the methods used in the broader range of conditions. The results obtained show that the catalytic activity of ion exchangers can be increased substantially either by increasing the total number of acid functional groups, or, particularly, by such treatment which makes the maximal number of the present functional groups accessible to reaction components. However, by the chemical procedures used to enhance the activity, the ion exchangers acquire frequently also some properties which affect negatively their application as catalysts.

scholarly journals Mechanism of adsorption of cadmium and lead ions by iron-activated biochar

BioResources ◽  
2018 ◽  
Vol 14 (1) ◽  
pp. 842-857 ◽  
Author(s):  
Liqiang Cui ◽  
Tianming Chen ◽  
Chuntao Yin ◽  
Jinlong Yan ◽  
James A. Ippolito ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Functional Groups ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Ferrous Ammonium Sulfate ◽  
Activated Biochar ◽  
Wide Ph Range ◽  
Ph Range ◽  
Cadmium And Lead ◽  
Ferrous Ammonium

Heavy metal removal from aqueous matrices may help reduce disease and cancer incidences. In this study, reed biochar (RBC) and RBC modified by ferrous ammonium sulfate addition (1 mol Fe L-1) were compared for potential Cd and Pb removal from varying pH aqueous solutions. Surface functional groups were identified using Fourier transform infrared (FTIR) analysis, and their surface physicochemical structure was observed using scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). Batch experiments showed that the modified-reed biochar (MRBC) had greater Cd and Pb removal capacities over a wide pH range (1 to 8), as well as greater metal sorption capacities compared to RBC. Metal reaction kinetics occurred relatively quickly (i.e., within 60 min), and Langmuir modeling suggested that Cd and Pb removal by MRBC was maximized at 2.97 mg g−1 and 17.5 mg g−1 at 45 °C, respectively. The MRBC effectively sorbed Cd and Pb likely due to associations with functional groups modified by the Fe addition. In the future, MRBC may be used as an efficient and eco-friendly adsorbent for Cd and Pb removal from aqueous solutions and may help reduce water-borne issues associated with metal contamination.

Multipurpose filters with ion-exchanger for the equalization of ammonia peaks

1995 ◽  
Vol 32 (7) ◽  
pp. 199-206 ◽  
Author(s):  
Martin Oldenburg ◽  
Ivan Sekoulov
Keyword(s):  
Operation Time ◽  
Ion Exchanger ◽  
Filter Medium ◽  
Nitrification Rate ◽  
Ion Exchangers ◽  
Flow Rates ◽  
Hydraulic Loading ◽  
Influent Concentration

In this study the use of zeolites as ion-exchangers for equalization of ammonia peak loadings in aerated biological activated filters was investigated. For this use zeolites were mixed with a filter medium and the nitrifying filter was loaded with ammonia peaks for two hours at different flow rates. It could be demonstrated that during the phase of higher inflow concentrations the zeolite was collecting ammonia. When the influent concentration decreased ammonia was desorbed from the zeolite and could be nitrified by the bacteria growing on the filter medium. It was shown that additional zeolites can equalize variations of ammonia, especially in filter units which are working at a high nitrification rate and which are very sensitive to varying influent conditions. During the operation time of the filter no separation of the zeolite by higher hydraulic loading or by backwashing could be recognized. So the upgrading of nitrifying filters with zeolite represents an additional security for effluents containing oscillating ammonia concentrations.

Sign in / Sign up

Export Citation Format

Share Document