Enrichment of Cs+, Ca2+ and Tl+ ions with microbiological collectors

Spicaria Violacea Abbott fungus was used as a microbiological collector for¹³⁷Cs⁺,⁴⁵Ca²⁺ and²⁰⁴Tl⁺ isotopes. The optimal conditions for the enrichment of these isotopes with respect to pH, time and concentration have been studied.     

Silver sorption on acrylic copolymers functionalized with amines. Equilibrium and kinetic studies

The sorption capacity of three weak base ion exchangers based on acrylic copolymers functionalized with ethylenediamine, triethylenetetramine and N, N- dimethylamino propylamine for Ag(I) ions was evaluated. Adsorption experiments were carried out by batch method. The effect of pH, crosslinking degree of copolymers, amount of sorbent, initial ion concentration, contact time and temperature was studied. The parameters which characterize the retention process were estimated using Langmuir and Freundlich isotherm models, the best fitting being for the first model. Kinetic data were fitted to pseudo-first order, pseudo-second order and intraparticle diffusion models. Experimental data were in good agreement with the pseudo second order.      

Concentration of Co2+, Fe3+ and Zn2+ ions with microbiological collectors

By means of Spicaria Violacea Abbott fungus, a microbiological method of concentration and separation of cobalt, iron and zinc is given. The influence of the experimental conditions, i.e. pH, time and concentration have been investigated.     

Study by thermal methods on the materials obtained by dye removal from waste waters with beech flour

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 fuel. 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.