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Biosorption of heavy metals fromleachates generated at mine waste disposal sites

Petrisor I.G, Komnitsas Konstantinos, Lazar I. , Voicu A. , Dobrota S. , Stefanescu M.

Πλήρης Εγγραφή

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Περίληψη

In the present paper, the efficiency of adsorbents and biosorbents for the removal of metal ions and theclean up of leachates, generated at two Romanian mine waste disposal sites is examined. Severaladsorbents such as activated charcoal, molecular sieve, shell sand, diatomite, bentonite, kaolin, as well asbiosorbents such as xanthan biopolymer and waste biomasses are assessed, in terms of metal ion removalefficiency, in laboratory glass columns, comprising layers of coarse sand and 3 layers of eachadsorbent/biosorbent. The effect of immobilized bacterial cells (naturally occurring consortia of acidophilicheterotrophic and chemolithotrophic bacteria) was also studied. The experimental results show that shellsand, molecular sieve and waste biomass have a relatively high efficiency in removing most heavy metalions present in low pH leachates. Regarding shell sand and for the experimental conditions used, theselectivity follows the order Pb>As>Cd>Ni>Cu>Zn>Al>Co>Mn. From the two types of the isolated fromleachates inoculum used as immobilized biomass, only heterothrophic acidophilic bacteria had a positiveeffect on metal uptake in contrary to chemolithotrophic acidophilic bacteria. The sufficient metal removalefficiency attained even without the use of immobilized bacteria, is mainly due to the stimulation ofnaturally occurring microbiota by addition of culture media; this stimulation may be considered as a feasiblealternative to the use of immobilized cells in biosorption applications, regardless of the type ofadsorbent/biosorbent used and the metal ion in concern.

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