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Ispitan je proces uklanjanja kadmija i cinka postupkom u koloni iz binarne ekvimolarne vodene otopine ukupne početne koncentracije c o (Cd+Zn) ≈ 1 mmol/L pri protocima od Q = 1, 2 i 3 mL/min. Provedena su tri radna ciklusa i tri ciklusa regeneracije na istom uzorku zeolita visine sloja od 8 cm. Iz eksperimentalnih rezultata nacrtane su krivulje proboja i krivulje regeneracije, izračunati su karakteristični parametri te je utvrđena učinkovitost procesa. Povećanjem protoka otopine proboj i iscrpljenje se pojavljuju ranije, smanjuje se kapacitet zeolita i efikasnost kolone. Prirast ukupne količine (Cd+Zn) iona vezanih na zeolitu linearno raste od početka eksperimenta nakon čega se počinje smanjivati (točka infleksije) što ukazuje na promjenu mehanizma koji kontrolira ukupnu brzinu procesa. Primjenom Advekcijsko-disperzijsko-reakcijskog modela (ADR) izračunat je koeficijent aksijalne disperzije, D L , pomoću kojega je izračunat koeficijent prijenosa tvari, k f kroz difuzijski granični sloj čestice zeolita. Utvrđeno je da je utjecaj aksijalne disperzije izraženiji za veće protoke otopine kroz sloj jer otopina zaobilazi dio čestica u zeolitnom sloju zbog nedovoljnog kontakta između otopine i zeolita. Najveća vrijednost k f utvrđena je u točki proboja, a zatim opada prema točki iscrpljenja uslijed povećanja debljine difuzijskog graničnog sloja. Do područja infleksije brzinu procesa kontrolira prijenos tvari konvekcijom u tekućoj fazi, a nakon infleksije prijenos tvari difuzijom kroz česticu. Povećanjem protoka može se obraditi veći volumen otopine u kraćem vremenu, međutim protok postaje ograničavajući faktor jer uslijed njegova povećanja dolazi do pojave aksijalne disperzije koja dovodi do smanjenja efikasnosti kolone. Removal of cadmium and zinc from equimolar binary aqueous solution of total initial concentration of c o (Cd+Zn) ≈ 1 mmol/L has been investigated using the column process at the flow rates of Q = 1, 2 and 3 mL/min. Three service and three regeneration cycles were performed on the same zeolite bed with height of 8 cm. The experimental results are shown by breakthrough and regeneration curves, and the characteristic parameters have been calculated as well as removal efficiency. By increasing in flow rate, the breakthrough and exhaustion points occured earlier, while zeolite capacity and column efficiency decreased. The quantity of (Cd+Zn) ions increases linearly from the beginning of the experiment, after that decrease (inflection point) indicating a change in mechanism which controls the overall process rate. The Advection-Dispersion-Reaction (ADR) model was applied for calculation of the axial dispersion coefficient, D L from which the mass transfer coefficient, k f , through the diffusion boundary layer has been calculated. The impact of axial dispersion is more pronounced for higher flow rates because of the solution bypassing some of the zeolite particles due to insufficient contact between the solution and the zeolite layer. The highest value of k f is observed in the breakthrough point, and then decreases to the exhaustion point due to increase in thickness of diffusion boundary layer. Up to inflection, the mass transfer by convection through the liquid phase controls the overall procces rate, and after that the mass transfer by diffusion through the boundary layer of the zeolite particle. By increasing in flow rate a larger volume of the solution can be treated in a shorter time, but the flow of the solution becomes a limiting factor because with its increase, an axial dispersion occurs which consequently results in a reduction of column efficiency.

Rudnik Idrija u Sloveniji bio je značajan antropogeni izvor žive. Iako je još 1995. godine proizvodnja u rudniku prestala, zbog neučinkovitog pečenja rude tlo u okolici Idrije je vrlo onečišćeno živom čija koncentracija doseže i do 10 000 mg Hg/kg. U tako krškom području živa se površinskim i oborinskim vodama može isprati u dublje slojeve tla te može doći do podzemnih voda. Budući da je živa jedan od najtoksičnijih metala, nužno je pronaći učinkovitu, a isplativu metodu za uklanjanje žive iz onečišćenih voda. U ovome radu ispitana je učinkovitost prirodnog zeolita klinoptilolita veličine čestica 0,6 - 0,8 mm u obradi eluata dobivenog ispiranjem živom onečišćenog tla s područja Idrije. Najveći učinak uklanjanja dobiven je u eluatima s najnižom koncentracijom ukupne žive, koja se smanjila do ispod maksimalno dopuštenih koncentracija. Najveća ravnotežna količina vezane ukupne žive po jedinici mase zeolita postignuta je u eluatima s najvećom koncentracijom ukupne žive te opada smanjenjem početne koncentracije. Prirodni zeolit klinoptilolit može se uspješno primjeniti u obradi voda onečišćenih živom, posebice u slučaju niskih početnih koncentracija ukupne žive. Međutim, u svrhu povećanja učinkovitosti prirodnog zeolita za uklanjanje ukupne žive nužno je poboljšati njegova površinska svojstva za adsorpciju različitih ionskih i organskih vrsta, što se najčešće postiže modifikacijom organskim surfaktantima. The Idrija mine in Slovenia was a significant anthropogenic source of mercury. Although the production in the mine stopped in 1995, the soil in surrounding of Idrija is highly polluted with mercury due to the inefficient ore roasting, so the concentration reaches even up to 10 000 mg Hg/kg. In such karst area, surface and rain waters can leach mercury from contaminated soil to deeper soil layers and then into groundwater. Since mercury is one of the most toxic metals, it is necessary to find an efficient, cost- effective method for its removal from contaminated waters. This paper investigated the efficiency of the natural zeolite clinoptilolite of particle size 0.6 - 0.8 mm in the treatment of the leachate obtained by leaching the mercury contaminated soil of Idrija district. The highest removal efficiency has been obtained in leachates with the lowest concentration of total mercury, which has been decreased to below the maximum permissible concentration. The highest equilibrium quantity of removed total mercury per unit of the zeolite mass has been achieved in the leachates with the highest concentration of total mercury, and decreased by decreasing in initial concentration. The natural zeolite clinoptilolite can be successfully applied for the treatment of mercury contaminated waters, especially in the case of low initial total mercury concentrations. However, in order to increase the efficiency of natural zeolite for total mercury removal, it is necessary to improve the surface properties of zeolite for adsorption of various ionic and organic species, which is most commonly achieved by modification with organic surfactants.