Influence of soil humic acid and fulvic acid on sorption of thorium(IV) on MX-80 bentonite

2006 ◽  
Vol 94 (8) ◽  
Author(s):  
D. Xu ◽  
X. K. Wang ◽  
C. L. Chen ◽  
X. Zhou ◽  
X. L. Tan
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Sorption Isotherms ◽  
Positive Influence ◽  
Low Ph ◽  
Ph Values ◽  
Batch Technique ◽  
Soil Humic Acid ◽  
Drastic Effect ◽  
Chemical Analogue

SummaryTh(IV) is considered herein as a chemical analogue of other actinides (IV). Effect of pH, ionic strength and humic acid/fulvic acid concentrations on the sorption of thorium(IV) to MX-80 bentonite was studied by batch technique. The sorption isotherms were acquired by varying pH in the range of 0.5–12 and FA/HA concentration in the range of 2–20 mg/L. The results indicate that soil fulvic acid has higher carboxylic content than humic acid, and has stronger positive influence on the sorption of Th(IV) on bentonite at low pH values than humic acid. The increase of FA/HA concentration results in a slight increase of Th(IV) sorption on FA/HA coated bentonite. The results of no drastic effect of different addition sequences of FA/HA and Th(IV) to bentonite suspension on Th(IV) sorption in the ternary system HA/FA-Th(IV)-bentonite indicate that both the Th(IV)-HA/FA complexation and HA/FA-bentonite sorption do not affect the sorption of Th(IV) on HA/FA coated bentonite obviously. The samples were also measured by SEM method and the results show that the surface properties of different samples are different.

β-Zeolite modified by ethylenediamine for sorption of Th(IV)

2017 ◽  
Vol 105 (6) ◽  
Author(s):  
Liu Peng ◽  
Wu Hanyu ◽  
Yuan Ni ◽  
Yin Zhuoxin ◽  
Pan Duoqiang ◽  
...  
Keyword(s):  
Steady State ◽  
Humic Acid ◽  
Ionic Strength ◽  
Contact Time ◽  
Surface Complexation ◽  
Sorption Isotherms ◽  
Ph Values ◽  
Β Zeolite ◽  
Batch Technique ◽  
Pseudo Second Order

Abstractβ-Zeolite-EDA was modified with ethylenediamine (EDA) after synthesized. The synthesized material was characterized and used for removal of Th(IV) from aqueous solutions. The influences of pH, ionic strength, contact time, temperature and humic acid (HA) on Th(IV) sorption onto synthesized β-zeolite-EDA was studied by batch technique. The dynamic process showed that the sorption of Th(IV) onto β-zeolite-EDA matched the pseudo-second-order kinetics model. The sorption of Th(IV) on β-zeolite-EDA was significantly dependent on pH values, the sorption percentage increased markedly at pH 3.5–4.5, and then maintained a steady state as pH values increased. Through simulating the sorption isotherms by Langmuir, Freundlich and Dubini–Radushkevich (D–R) models, it could be seen respectively that the sorption pattern of Th(IV) on β-zeolite-EDA was mainly controlled by surface complexation, and that the sorption processes was endothermic and spontaneous. The presence of HA increased Th(IV) sorption on β-zeolite-EDA.

scholarly journals Mechanism of Coagulation of Humic Acid in Presence of Metal Ion Coagulants at Low pH Values

1970 ◽  
Vol 73 (5) ◽  
pp. 874-878 ◽  
Author(s):  
Takao YOTSUYANAGI ◽  
Katsumi GOTO ◽  
Masaichi NAGAYAMA
Keyword(s):  
Humic Acid ◽  
Metal Ion ◽  
Low Ph ◽  
Ph Values

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.

Adsorption of Th(IV) onto Al-pillared rectorite: Effect of pH, ionic strength, temperature, soil humic acid and fulvic acid

2008 ◽  
Vol 38 (3-4) ◽  
pp. 219-226 ◽  
Author(s):  
S.M. Yu ◽  
C.L. Chen ◽  
P.P. Chang ◽  
T.T. Wang ◽  
S.S. Lu ◽  
...  
Keyword(s):  
Humic Acid ◽  
Ionic Strength ◽  
Fulvic Acid ◽  
Effect Of Ph ◽  
Soil Humic Acid

Uranium(VI) complexation with citric, humic and fulvic acids

2000 ◽  
Vol 88 (6) ◽  
Author(s):  
J.J. Lenhart ◽  
S.E. Cabaniss ◽  
P. MacCarthy ◽  
Bruce D. Honeyman
Keyword(s):  
Humic Acid ◽  
Fulvic Acid ◽  
Ph Dependence ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
Binding Model ◽  
High Affinity ◽  
Ph Values ◽  
Mononuclear Complexes ◽  
Large Size

The binding of uranium(VI) by Suwannee River humic and fulvic acids was studied at pH values of 4.0 and 5.0 in 0.10 M NaClOBoth humic and fulvic acids were demonstrated to strongly bind U(VI), with humic acid forming slightly stronger complexes and exhibiting greater pH dependence. Analyses of the data for the humic and fulvic acid systems using the Schubert´s equation previously applied to the citrate system result in an apparent nonintegral number of ligands binding the uranyl ion. Schubert´s method is only appropriate for interpreting mononuclear complexes with integral moles of binding ligands. Thus, a more elaborate binding model was required and the data were interpreted assuming either: (1) a mixture of 1:1 and 1:2 uranyl-ligand complexes or (2) a limited number of high affinity sites forming a 1:1 complex. While both of these modeling approaches are shown to provide excellent fits to the data, the second is deemed more appropriate given the large size of humic and fulvic acid molecules as well as previous results obtained with other metal cations, such as Cu(II).

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Characteristics of fouling due to clay-organic substances in potable water treatment by ultrafiltration

1996 ◽  
Vol 34 (9) ◽  
pp. 157-164 ◽  
Author(s):  
Kim C.-H. ◽  
M. Hosomi ◽  
A. Murakami ◽  
M. Okada
Keyword(s):  
Molecular Weight ◽  
Organic Matter ◽  
Humic Acid ◽  
Fulvic Acid ◽  
Size Distribution ◽  
Ultrafiltration Membrane ◽  
Organic Substances ◽  
Decomposition Products ◽  
Microbial Decomposition ◽  
Fouling Materials

Effects of clay on fouling due to organic substances and clay were evaluated by model fouling materials and kaolin. Model fouling materials selected were protein, polysaccharide, fulvic acid, humic acid and algogenic matter (EOM:ectracellular organic matter, microbial decomposition products) and kaolin was selected as the clay material. Polysulfone membrane (MWCO(Molecular Weight Cut-Off) 10,000, 50,000 and 200,000) was used as an ultrafiltration membrane. In particular, the flux measurement of solutions containing algogenic matter used an ultrafiltration membrane of MWCO 50,000. The flux of protein and polysaccharide with coexistence of kaolin increased in the case of the ratio of MW/MWCO being greater than one, but did not increase in the case of the MW/MWCO ratio being below one. In contrast, the flux of fulvic acid and humic acid with coextence of kaolin decreased regardless of the ratio of MW/MWCO. The addition of dispersion agent and coagulant in the organic substances and kaolin mixture solution changed the size distribution of kaolin, and resulted in a change of the flux. EOM and microbial decomposition products decreased with the increase of the fraction of organic matter having molecular weight more than MWCO of membrane. The flux of the algogenic organic matter with coexistence of kaolin decreased with the increase of the amount of kaolin. It was suggested that the decline of the flux with coexistence of kaolin was due to the change of the resistance of the kaolin cake layer corresponding to the change in kaolin size distribution with charge.

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