Complexation of Transuranic Ions by Humic Substances: Application of Laboratory Results to the Natural System

1996 ◽  
Vol 465 ◽  
Author(s):  
Ken Czerwinski ◽  
Jae-Il Kim
Keyword(s):  
Humic Acid ◽  
Humic Substances ◽  
Metal Ion ◽  
Ion Concentration ◽  
Mixed Species ◽  
Experimental Conditions ◽  
Aquifer System ◽  
Natural Systems ◽  
Species Formation ◽  
Laboratory Results

ABSTRACTEnvironmental investigations show transuranic ions sorb to humic substances. The resulting species are often mobile and are expected to be important vectors in the migration of transuranic ions in natural systems. However, theses environmental studies yield no quantitative data useful for modeling. Laboratory complexation experiments with transuranic ions and humic substances generate mermodynamic data required for complexation modeling. The data presented in this work are based on the metal ion charge neutralization model, which is briefly described. When a consistent complexation model is used, similar results are obtained from different experimental conditions, techniques, and laboratories. Trivalent transuranic ions (CM(III), AM(III)) have been extensively studied with respect to pH, ionic strength, origin of humic acid, and mixed species formation. The complexation of Np(V) has been examined over a large pH and metal ion concentration range with different humic acids. Some data does exist on the complexation of plutonium with humic acid, however further work is needed. Calculations on the Gorleben aquifer system using the thermodynamic data are presented. Critical information lacking from the mermodynamic database is identified.

Uptake of Neutral Metal Complexes by a Green Alga: Influence of pH and Humic Substances

2004 ◽  
Vol 57 (10) ◽  
pp. 931 ◽  
Author(s):  
Amiel Boullemant ◽  
Bernard Vigneault ◽  
Claude Fortin ◽  
Peter G. C. Campbell
Keyword(s):  
Humic Acid ◽  
Metal Complex ◽  
Metal Complexes ◽  
Humic Substances ◽  
Low Ph ◽  
Pseudokirchneriella Subcapitata ◽  
Short Term ◽  
Experimental Conditions ◽  
Influence Of Ph ◽  
Neutral Metal

We have examined the influence of pH and a natural humic acid on the short-term uptake (<40 min) of a neutral, lipophilic metal complex by a unicellular freshwater alga, Pseudokirchneriella subcapitata. Cadmium diethyldithiocarbamate ([Cd(DDC)2]0) was used as a model lipophilic metal complex and Suwannee River Humic Acid (SRHA) was chosen as a representative aquatic humic acid (6.5 mg C L−1). Under the experimental conditions virtually all the Cd was expected to be present as the lipophilic complex ([Cd]T = 0.38 nM; [DDC] 1 μM; [Cd2+] <10−15 M; pH 7.0, 6.0, or 5.5). Uptake of [Cd(DDC)2]0 proved to be sensitive to pH changes. It was lower at pH 6.0 and 5.5 than at pH 7.0. To our knowledge, this is the first demonstration of reduced uptake of a lipophilic metal complex at low pH. The presence of SRHA also affected uptake, either by binding the lipophilic complex in solution and reducing its bioavailability (pH 7.0) or by increasing the permeability of the algal membrane (pH 5.5).

scholarly journals Schiff Base Anchored with Silver Nanoparticles as Effective Adsorbent for Removal of Cadmium(II) Heavy Metal from Industrial Wastewater

2020 ◽  
Vol 32 (8) ◽  
pp. 1941-1946
Author(s):  
Preeti Sharma ◽  
Vedula Uma
Keyword(s):  
Silver Nanoparticles ◽  
Schiff Base ◽  
Contact Time ◽  
Industrial Wastewater ◽  
Metal Ion ◽  
Solid Phase ◽  
Chemical Reduction ◽  
Ion Concentration ◽  
Spectral Studies ◽  
Experimental Conditions

The current study deals with the examination of the capacity of Schiff base anchored with silver nanoparticles for removal of cadmium(II) ions from industrial wastewater. Schiff base was synthesized using refluxing of salicylaldehyde and 4-aminoantipyrine in alcoholic medium. The characterization of Schiff base were studied by elemental analysis, FTIR, NMR, UV-visible and mass spectral studies. The silver nanoparticles were synthesized using the chemical reduction method and characterized. Then, silver nanoparticles anchored to the Schiff base by suitable method and again characterized. Peanut shells were used as solid phase for removal of Cd(II) ions. The effects of several parameters to optimize the adsorption of Cd(II) ions on solid phase, including pH, contact time, initial metal ion concentration and adsorbent weight were investigated. The maximum removal efficiency of Cd(II) ions on solid phase using Ag nano@Schiff base was achieved under experimental conditions of pH 6 (% removal = 81%), contact time of 15 min (% removal = 93%), initial metal ion concentration of 0.5 ppm (% removal = 95%) and adsorbent weight of 3 mg (% removal = 89%). The results showed that extraction of Cd2+ on AgNPs@Schiff base follows Freundlich adsorption isotherm.

scholarly journals Modeling of Copper Adsorption on Mesoporous Carbon CMK-3: Response Surface Design

2018 ◽  
Vol 2 (4) ◽  
pp. 49
Author(s):  
Zeinab Ezzeddine ◽  
Isabelle Batonneau-Gener ◽  
Yannick Pouilloux
Keyword(s):  
Response Surface ◽  
Metal Ion ◽  
Mesoporous Carbon ◽  
Sorption Isotherms ◽  
Ion Concentration ◽  
Batch Adsorption ◽  
Response Surface Design ◽  
Experimental Conditions ◽  
Copper Adsorption ◽  
Surface Design

CMK-3 mesoporous carbon was nanocast from SBA-15 silica. The obtained carbon was characterized by nitrogen sorption isotherms, X-ray diffraction and transmission electron microscopy (TEM). The batch adsorption tests were done at constant pH taking into account the initial metal ion concentration, adsorbent mass and temperature. A statistical study using a response surface design method was done to develop a mathematical model to predict copper adsorption on CMK-3 as a function of the mentioned experimental factors. It was found that all these parameters are significant, and copper concentration has the greatest effect on adsorption among them. Moreover, the obtained model proved to be adequate in predicting copper adsorption on CMK-3 and its performance under different experimental conditions.

scholarly journals Adsorption of Cr(Vi) Ion from Aqueous Solutions by Solid Waste of Potato Peels

2017 ◽  
Vol 5 (3) ◽  
pp. 254 ◽  
Author(s):  
Nidhal M. Sher Mohammed ◽  
Haydar A. Mohammad Salim
Keyword(s):  
Aqueous Solutions ◽  
Metal Ion ◽  
High Efficiency ◽  
Low Cost ◽  
Ion Concentration ◽  
Potato Peel ◽  
Order Model ◽  
Experimental Conditions ◽  
Langmuir Adsorption ◽  
Potato Peels

Pollution of wastewater with heavy metal has always been a serious problem to the environment. Chromium is considered one of the most noxious heavy metals. Adsorption is now reorganized as an alternative technology of defence for chromium removal due to local availability, technical efficiency and cost effectiveness. Potato peel powder can be used as a low cost biosorbent to remove hexavalent chromium from aqueous solutions under various experimental conditions. Different parameters including equilibrium contact time, initial metal ion concentration, potato peel dose, pH and temperature were studied through a number of batch sorption experiments. Both the Langmuir and Freundlich were found to fit the adsorption isotherm of Cr (VI) ion onto potato peel. The Langmuir adsorption capacity was found to be 1.97 mg/g while Freundlich constants including Kf and n were 1.57 and 2.5, respectively. The adsorption kinetic was found to be more fit with the pseudo-first order model. This study showed a high efficiency of potato peel for the biosorption of Cr (VI) ion from aqueous solutions.

scholarly journals ADSORPTION KINETICS OF Pb(II), Cd(II) AND Cr(III) ON ADSORBENT PRODUCED BY PROTECTED-CROSSLINKING OF HUMIC ACID-CHITOSAN

2010 ◽  
Vol 10 (1) ◽  
pp. 80-87
Author(s):  
Dewi Umaningrum ◽  
Uripto Trisno Santoso ◽  
Radna Nurmasari ◽  
Rahmat Yunus
Keyword(s):  
Humic Acid ◽  
Adsorption Kinetics ◽  
Metal Ion ◽  
Second Order ◽  
Adsorption Rate ◽  
Ion Concentration ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Rate Limiting ◽  
Kinetics Of

Study on adsorption kinetics of of Pb(II), Cd(II) and Cr(III) on adsorbent which was produced by protected-crosslinking of humic acid-chitosan has been done. The Langmuir-Hinshelwood, pseudo first- and second-order kinetics models were used to describe the kinetic data, and the rate constants of adsorption were also evaluated. The experimental data fitted well the second-order kinetics model, indicating that the chemical sorption is the rate-limiting step, instead of mass transfer. The initial metal ion concentration significantly affects the adsorption rate. An increase in initial metal ion concentration results in the decrease in adsorption rate of the metals.   Keywords: kinetics, adsorption, crosslinking, humic acid, chitosan

scholarly journals Factors affecting the dissociation of metal ions from humic substances

2015 ◽  
Vol 79 (6) ◽  
pp. 1397-1405 ◽  
Author(s):  
Nick Bryan ◽  
Dominic Jones ◽  
Rose Keepax ◽  
Dean Farrelly ◽  
Liam Abrahamsen ◽  
...  
Keyword(s):  
Humic Acid ◽  
Metal Ions ◽  
Humic Substances ◽  
Rate Constants ◽  
Metal Ion ◽  
Dissociation Rate ◽  
Factors Affecting ◽  
Ion Concentrations ◽  
Dissociation Rate Constants ◽  
Actinide Ions

AbstractPreviously, it has been suggested that metal ions complexed to humic acid in the environment might show slower dissociation than those added to humic substances in the laboratory, which has serious implications for the transport of radionuclides in the environment. The dissociation of lanthanide and anthropogenic actinide ions from humic substance complexes has been studied as a function of humic concentration and metal ion:humic concentration ratio. The results suggest that the apparently slower kinetics observed for metal ions complexed in the environment are probably due to the large humic concentrations that are used in those studies. Further, there is no evidence that the dissociation rate constant varies at very low metal ion concentrations. Although humic samples size-fractionated by ultrafiltration showed that more metal may be bound non-exchangeably, there was no evidence for different rate constants. Ultrafiltration of Eu(III)/humic acid mixtures did show a shift in Eu from smaller to larger fractions over a period of two days. Therefore, the results suggest that dissociation rate constants determined in the laboratory at metal ion concentrations higher than those expected in the environment may be used in predicting radionuclide mobility, provided that the humic acid concentration is in the range expected at the site.

Reclamation of Hexavalent Chromium from Electroplating Effluents by Electroextraction

2020 ◽  
Vol 20 (10) ◽  
pp. 6547-6554
Author(s):  
M. Revathi ◽  
G. Sivagaami Sundari ◽  
C. Ahmed Basha ◽  
Manawwer Alam ◽  
Suresh Sagadevan ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Continuous Flow ◽  
Metal Ion ◽  
Industrial Effluent ◽  
Ion Concentration ◽  
Treated Wastewater ◽  
Flow Mode ◽  
Experimental Conditions ◽  
Flow Process ◽  
Electrochemical Ion Exchange

This investigation aims at the reclamation of Cr(VI) from synthetic electroplating industrial effluent by electroextraction process namely electrochemical ion exchange (EIX). An electrochemical ion exchange reactor of desired dimensions was fabricated with the help of ion-permeable membranes, stainless steel cathode and PbO2 coated Ti expanded mesh anode. The performance of the reactor was studied in batch recirculation mode, continuous flow mode at different experimental conditions. The influence of various experimental factors, for instance, initial metal ion concentration (20, 300, 1000 mg/L of Cr(VI)), applied voltages (2.5 V, 5 V, 7.5 V, 10 V) and flow rates of the process stream (2, 4, 6, 8, 10, 12 and 14 ml/min) on removal/reclamation efficiency was deliberated. For comparison purposes, an electrodialysis process was conducted at the same optimal conditions. It was found that the EIX process with three compartments has more removal efficiency at optimum experimental conditions than the electrodialysis process. The continuous flow process of the reactor with 300 mg/L of Cr(VI) as inlet concentration has studied to predict the breakeven point of the reactor. It was noted that Cr(VI) ion concentration in the treated wastewater is almost zero up to the discharge of 20 liters of treated rinse water.

scholarly journals Kinetics of Adsorption of Ferrous Ion onto Acid Activated Carbon fromZea MaysDust

2011 ◽  
Vol 8 (1) ◽  
pp. 185-195 ◽  
Author(s):  
P. K. Baskaran ◽  
B. R. Venkatraman ◽  
S. Arivoli
Keyword(s):  
Langmuir Isotherm ◽  
Metal Ion ◽  
Low Cost ◽  
Mineral Acid ◽  
Ion Concentration ◽  
Ferrous Ion ◽  
Isotherm Models ◽  
Ferrous Ions ◽  
Experimental Conditions ◽  
Kinetics Of Adsorption

The batch removal of ferrous ion from aqueous solution using low cost adsorbents such aszea maysdust carbon(ZDC) under different experimental conditions were investigated in this study. The process parameters studied include agitation time, initial metal ion concentration, carbon dose, pH and temperature. The adsorption followed first order reaction equation and the rate is mainly controlled by intraparticle diffusion. Freundlich and Langmuir isotherm models were applied to the equilibrium data. The adsorption capacity (Qm) obtained from the Langmuir isotherm plot were found to 37.17, 38.31, 39.37 and 40.48 mg/g. The temperature variation study showed that the ferrous ions adsorption is endothermic and spontaneous with increased randomness at the solid solution interface. Significant effect on adsorption was observed on varying the pH of the ferrous ion solutions. The Langmuir and Freundlich adsorption isotherms obtained positive ΔH0value, pH dependent results and desorption of metal ions in mineral acid suggest that the adsorption of ferrous ion on ZDC involves physisorption mechanism.

Use of agro-waste (Musa paradisiaca peels) as a sustainable biosorbent for toxic metal ions removal from contaminated water

2019 ◽  
Author(s):  
Chem Int
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Contact Time ◽  
Metal Ion ◽  
Equilibrium Concentration ◽  
Ion Concentration ◽  
Contaminated Water ◽  
Musa Paradisiaca ◽  
Percentage Removal ◽  
Adsorbent Dose

A study of removal of heavy metal ions from heavy metal contaminated water using agro-waste was carried out with Musa paradisiaca peels as test adsorbent. The study was carried by adding known quantities of lead (II) ions and cadmium (II) ions each and respectively into specific volume of water and adding specific dose of the test adsorbent into the heavy metal ion solution, and the mixture was agitated for a specific period of time and then the concentration of the metal ion remaining in the solution was determined with Perkin Elmer Atomic absorption spectrophotometer model 2380. The effect of contact time, initial adsorbate concentration, adsorbent dose, pH and temperature were considered. From the effect of contact time results equilibrium concentration was established at 60minutes. The percentage removal of these metal ions studied, were all above 90%. Adsorption and percentage removal of Pb2+ and Cd2+ from their aqueous solutions were affected by change in initial metal ion concentration, adsorbent dose pH and temperature. Adsorption isotherm studies confirmed the adsorption of the metal ions on the test adsorbent with good mathematical fits into Langmuir and Freundlich adsorption isotherms. Regression correlation (R2) values of the isotherm plots are all positive (&gt;0.9), which suggests too, that the adsorption fitted into the isotherms considered.

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