Učinkovitost biološkog uklanjanja šesterovalentnog kroma suspendiranom i imobiliziranom mikrobnom biomasom na pucolanu: proučavanje mehanizma samočišnjenja

Hexavalent chromium is one of the hazardous metals that can be found in industrial effluents such as wood treatment units, mining, leather tanning, pigment, steel and electroplating industry. The present work aimed to evaluate the self-purification capacity of the microbial flora taken from the domestic wastewater effluent of Chlef City, with the perspective of designing a microbial bed in the secondary sewage treatment to prevent an industrial Cr(VI) contamination. Under various operating conditions, the bioremoval performance of Cr(VI) was evaluated by using suspended biomass and immobilised biomass (fixed onto pozzolana grains). The results showed that the immobilised biomass was more efficient and more resistant to Cr(VI) toxicity than the suspended biomass. Indeed, the Cr(VI) was totally eliminated within 96 h for an initial concentration of 50 mg l–1 by the immobilised biomass, while this rate was obtained after 120 h for the suspended biomass. The kinetic data fit well to the pseudo-first order kinetic model. The intraparticle diffusion kinetic model suggested that the diffusion process of Cr(VI) was greatly influenced by the initial concentration. The microbial flora present in domestic wastewater is a promising biosorbent that is able to treat effluent containing Cr(VI). This work is licensed under a Creative Commons Attribution 4.0 International License.Šesterovalentni krom je jedan od opasnih tvari koja se može naći u otpadnim tokovima drvne industrije, rudarstva, štavljenja kože, industrije pigmenta, čelika i galvanizacije. Cilj ovog rada bio je procijeniti kapacitet samopročišćavanja mikrobne flore uzete iz komunalnih otpadnih voda grada Chlefa, s perspektivom projektiranja mikrobnog sloja primjenjivog za sekundarnu obradu industrijskih voda s ciljem sprječavanja kontaminacije kromom(VI). Učinak biološkog uklanjanja šesterovalentnog kroma procijenjen je pri različitim radnim uvjetima primjenom suspendirane te imobilizirane biomase (fiksirane na zrna pucolana). Rezultati su pokazali da je imobilizirana biomasa učinkovitija i otpornija na toksičnost kroma(VI) od suspendirane biomase. Primjenom imobilizirane biomase, 50 mg l–1 kroma(VI) je potpuno uklonjeno tijekom 96 h dok je uz primjenu suspendirane biomase bilo potrebno 120 h. Kinetika odgovara modelima pseudo prvog reda. Kinetički model unutarčestične difuzije ukazao je na veliki utjecaj početne koncentracije kroma(VI) na proces njegove difuzije. Mikrobna flora prisutna u komunalnim otpadnim vodama obećavajući je sorbens koji se može primijeniti za pročišćavanje voda koje sadrže krom(VI). Ovo djelo je dano na korištenje pod licencom Creative Commons Imenovanje 4.0 međunarodna