Authors:L. Tochilina, L. Kaganov, and N. Mukhamedshina
A radiochemical neutron activation technique for Mo determination in high purity tungsten, based on some specific properties of Mo and W radionuclides has been developed. Al2O3 powder has been used as a sorbent. An estimation of the Mo content was carried out via the selectively separated99mTc daughter radionuclide. Limit of detection was 10 ng g–1.
The sorption of zinc and cadmium on zeolite rocks from different locations in Bulgaria is studied. The basic equilibrium and kinetic parameters are determined. It has been found that the clinoptilolite rock from the location Bali plast may be used as a sorbent for zinc and cadmium.
The possibility to use some cationic forms of the clinoptilolite as sorbents for radioactive iodine extraction form solutions is studied. The results obtained show that the silver form of clinoptilolite is the most promising for extraction of radioactive iodine from liquid radioactive wastes.
The adsorption of cesium and strontium ions from water solutions on zeolite has been investigated in presence of sodium, potassium, magnesium and calcium ions. Distribution ratios of cesium and strontium on the zeolite were determined in solutions of various compositions and solution volume to sorbent weight ratios (batch factor). Breakthrough curves for zeolite layers are reported.
Authors:Lucia Odochian, Viorica Dulman, M. Dumitraş, and A. Pui
The study is devoted to the characterization by both TG-DTG analysis and FTIR spectroscopy of beech flour, dyes and the sorbent-dyes
products obtained through retention of the dyes from aqueous solution on the beech flour, to the aim of obtaining information
on the nature of dyes’ retention, thermal behavior of the sorbent-dye materials as well as on their possible upgrading as
Thermal analysis led to the conclusion that the mechanism of thermo-oxidative degradation is specific and the retention of
dyes occurs on cellulose from beech flour. The nature of the bonds involved in dyes’ retention is also investigated by FTIR
analysis, which evidences that dyes retention on cellulose is realized through hydrogen bonding between the NH and, respectively,
OH groups from dye molecule and the oxygen atoms from cellulose. Involvement of the non-participating electrons of the nitrogen
and, respectively, oxygen atoms of these groups in the extended electronic conjugation with aromatic nuclei strongly influences
the capacity of the amino and, respectively, hydroxyl groups of forming hydrogen bonds, thus achieving dyes fixation on the
sorbent. DTA analysis led to the conclusion that an improvement in the quality of the sorbent-dye materials as fuels is possible,
as compared to untreated beach flour, as a result of the modification of the cellulosic fibers in the process of dyes retention.
This paper reports some ion-exchange column experiments, carried out to determine the breakthrough curves of137Cs and89Sr radioisotopes on a commercially available inorganic ion-exchange sorbent of the amorphous zirconium phosphate type. A dynamic capacity of about 3–4 meq·g–1 was observed.
Authors:A Barros, J Santos, S Prasad, V Leite, A Souza, L Soledade, M Duarte, and V dos Santos
The conventional treatments
of effluents containing heavy metals produce significant quantities of byproducts
with recalcitrant characteristics, making necessary looking after alternative
techniques in order to avoid the production of new contaminated residues.
Sorption process of chromium and zinc in vertical columns loaded with sewage
sludge and organic solid waste has been studied in this work. The data from
the TG curves of the two sorbents presented significant differences when they
were submitted to the metal uptake, being noticed the displacement of the
thermal events towards lower temperatures for both types of sorbents studied.
As it was expected, for both sorbents, an increase in the mass of samples
has been observed at the completion of the thermal tests upon metal uptake.
Therefore, these facts demonstrate that during the biosorption process a physico-chemical
interaction took place between sorbents and metals, as it was evidenced by
the more than 100 K increase in the decomposition temperatures as well as
the variation of the ΔH values of the
Authors:Marilda Vianna, Jo Dweck, Frank Quina, Flavio Carvalho, and Claudio Nascimento
This study investigates the sorption of toluene and naphthalene by a sodium bentonite (BFN), an organoclay (WS35) and by their
respective iron oxide hydrate composites Mag_BFN and Mag_S35. The organic matter content of WS35 and Mag_S35, determined by
thermogravimetry, was used to obtain their organic matter sorption coefficients, which show that they are effective sorbents
to remove organic contaminants from water, with a higher selectivity for naphthalene than for toluene sorption. The main iron
oxide phase present in Mag_BFN and Mag_S35 is maghemite (γ-Fe2O3), which allows these sorbents to be separated from the effluent by a magnetic separation process after use.
By using slow damped oscillations of a torsional pendulum, it is possible to determine the mass adsorbed on the surface of
a porous sorbent without buoyancy effects from the frequency and the logarithmic decrement of the pendulum motion. In principle,
it is then possible to determine directly the buoyancy-related volume Vas of the sorbent/sorbate system by combining the results with gravimetric measurements.
Measurements with a preliminary testing pendulum are presented for N2 and CH4 on the activated carbon Norit R1 Extra at ambient temperature in the pressure range 0<p<0.5 MPa. Values for Vas calculated from these measurements and gravimetrically determined data are presented and discussed to a certain extent.
Authors:Duygu Totur, Serap Bozkurt, and Melek Merdivan
A sensitive and selective solid phase extraction procedure for the determination of trace of uranium(VI) has been developed.
An alumina-sodium dodecyl sulfate coated on with pyrocatechol violet was used for preconcentration and determination of uranyl
ions by spectrophotometry method using Arsenazo III reagent. Sorbed ions were quantitatively eluted using 5 mL of 0.25 mol L−1 HNO3. The effects of parameters such as pH, amount of alumina, amount of ligand, flow rate, type and concentration of elution
agent were examined. The capacity of the sorbent for U(VI) was found to be 0.92 mmol g−1. The relative standard deviation was 1.28% for 10 replicate determinations of U(VI) ion in a solution with a concentration
of 1.0 μg mL−1. The practical applicability of the developed sorbent was examined using synthetic and real samples such as standard reference
material 2709 (San Joaquin Soil) and 2711 (Montana Soil).