engleski

Nitrate removal from aqueous solution by modified biomass

Modified hazelnut shells, brewers’ spent grain and grape seeds, all lignocellulosic food industry by-products, were evaluated as lowcost sorbents for nitrate removal from aqueous solutions in batch and column studies. Characterisation of the materials was performed in terms of elemental analysis (C, H, O, N), FTIR and SEM. The effects of contact time (2 – 1440 min), initial nitrate concentration (10 – 300 mg L-1), sorbent concentration (1 – 10 g L- 1) and pH (2 – 10) were investigated. Removal efficiencies over 90% were achieved. Maximum adsorption capacities ranged from 22 to 25 mg g-1, which is in accordance with the literature. It was shown that the adsorption data could be fitted in the linearized Freundlich and Langmuir model. Additionally, the sorption was very rapid and was well described by the pseudo-second order model, while intraparticle diffusion model suggests at least two steps during the adsorption process. Column experiments showed that these materials maintained nitrate removal ability during minimum three adsorption and desorption cycles. The column could be effectively regenerated with 0.1 M NaCl. The future aim is to study the adsorption process of other pollutants on different biomass.

nitrate, biomass, sorption, column study

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