Adsorption of dye on the biodegradable adsorbent

Grafična in tekstilna industrija sta velika porabnika vode, saj pri svoji procesih za obarvanje najpogosteje kot topilo uporabljata vodo, kar posledično pomeni, da zahtevata učinkovite sisteme za čiščenje odpadnih voda. Obarvanost vode ima več negativnih učinkov na okolje. V zadnjih letih se vedno več pozornosti namenja ekologiji, kar je spodbudilo rast uporabe adsorpcijske tehnologije za čiščenje odpadnih industrijskih voda. Pri adsorpciji se kot izredno učinkovit adsorbent najpogosteje uporablja aktivno oglje, vendar je problematična njegova cena. Ena od rešitev tega problema bi lahko bila uporaba biološko razgradljivih adsorbentov, ki so cenovno dostopni in predstavljajo najpogostejši odpadek v živilski industriji. V nalogi je bila testirana učinkovitost zmletih in predhodno posušenih mandarininih olupkov kot primer adsorbenta pri procesu adsorpcijskega čiščenja direktnega barvila iz trde in mehke vode pri različnih koncentracijah. Ugotovljeno je bilo, da je adsorpcija direktnega barvila na aktivno oglje v granulah bolj učinkovita kot na mandarinine olupke. Adsorpcija barvila na aktivno oglje v trdi vodi dobro sledi Langmuirjevi in Freundlichovi izotermi, medtem ko adsorpcija barvila na mandarinine olupke ne sledi nobeni od predpostavljenih adsorpcijskih izoterm. Adsorpcija barvila na aktivno oglje v granulah v mehki vodi doseže vrednosti razbarvanja, ki dovoljujejo odvajane v površinske vode, medtem ko pri adsorpciji barvila na mandarinine olupke ne pride do željenih vrednosti.Graphic and textile industries are large water users, since they use water mostly as a solvent in their coloring processes, which in turn means that they need efficient systems for waste water treatment. The coloring water has several negative effects on the environment. Over the last few years, increasing attention to ecology promoted growth in the use of adsorption technology for treatment of industrial waste water. In adsorption, the most commonly used adsorbent is activated carbon, which is very effective, but its price is problematic. One of the solutions could be biodegradable adsorbents which are affordable and represent the most common waste in the food industry. In this paper, the efficiency of milled and pre-dried mandarin peelings as an example of an adsorbent was tested in the adsorption of direct dye from the hard and soft water. It was found that the adsorption of direct dye onto activated carbon in granules is more effective than onto mandarin peelings. The adsorption of the direct dye onto activated carbon in hard water follows closely by Langmuir and Freundlich\u27s isotherms, however adsorption onto mandarin peelings does not follow any of the assumed adsorption isotherm. The adsorption of the dye onto activated carbon in granules in soft water it is so good that reaches the limit values that let discharged into surface waters, while the adsorption of the dyes onto mandarin peels does not reach the desired values