The parameters which influence the removal of different zinc (Zn) species: Zn2+, Zn(II)–EDTA and Zn(II)–citrate from aqueous solutions by nanoparticles of zero-valent iron (nZVI) were investigated at environmental relevant pH values. Untreated, surface modified and silica-fume supported nZVI were applied at different iron loads and contact times to Zn solutions, which were buffered to pH 5.3, 6.0 and 7.0. The results revealed that pH, the type of nZVI, the iron load, the contact time, and the Zn species all had a significant influence on the efficiency of removal. Zn2+, Zn(II)–EDTA and Zn(II)–citrate were the most effectively removed from aqueous solutions by untreated nZVI. Zn2+ removalwas governed mainly by adsorption onto precipitated iron oxides. Complete removal of Zn2+ and Zn(II)–citrate was obtained at all pH values investigated. The removal of strong Zn(II)–EDTA complexwas successful only at acidic pH,which favored degradation of Zn(II)–EDTA. Consequently, the released Zn2+ was completely removed from the solution by adsorption onto iron oxides.
COBISS.SI-ID: 27431207
The Port of Koper, one of the biggest and the most important ports in the Northern Adriatic Sea, is constantly faced with the problems caused by the accumulation of marine sediments inside the port, disturbing some of the portʼs crucial operations. However, these sediments can be viewed as a potential raw material and, in order to define the best way of using them in the civil-engineering field, an extensive research project has been launched. The preliminary results of this project are presented and discussed in the paper. So far the project has given two main results: first, the concentrationof heavy metals in the aqueous leachates is low and, secondly, intheir present state, the sediments are too wet, so that there are only limited possibilities for drying them out naturally. For this reason additional technological treatment will be needed.
COBISS.SI-ID: 1972071
In the study the dry end of the soil water characteristic curve (SWCC) was used to estimate the specific surface area (SSA) of 90 engineering soil samples, using the Tuller and Or (2005) model. The results of SSA obtained by measurements using a WP4T dew point potentiometer were compared with those obtained by means of traditional BET (Brunauer, Emmett, and Teller) surface area and the methylene blue (MB) techniques. An analysis of the results discussed in terms of the representative literature data showed that the SWCC method could provide a reliable estimation of the specific surface area in the case of fine grained inorganic soils with a total specific surface area greater than 5 m2/g. A Hamaker constant with a value of 6 × 10− 20 J was found to be a good approximation, in the case of SSA calculations. The study also shows that karstic clay — terra rossa exhibits specific behavior which was not investigated in detail in the study, but clearly shows that further research is needed in order to modify the Tuller and Or (2005) model to a wider range of engineering soils with more complex mineralogical composition and texture.
COBISS.SI-ID: 6328417