Naslov
Food industry by-product for nitrate removal

Autori
Nujić, Marija ; Habuda-Stanić, Mirna

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
18th European Meeting on Evironmental Chemistry - EMEC18 Book of Abstracts / Santos, MSF ; Silva, AM ; Santos, L ; Ratola, N ; Pinto, AMFR ; Pereira, MFR ; Homem, V ; Azevedo, NF ; Alves, A. - Porto : Sersilito-Empresa Grafica, Lda., 2017, 244-244

ISBN
978-972-752-228-6

Skup
18th European Meeting on Environmental Chemistry - EMEC18

Mjesto i datum
Porto, Portugal, 26.11.2017. - 29.11.2017

Vrsta sudjelovanja
Poster

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
nitrate removal, grape seed, ion exchange, adsorption isotherm, kinetic study

Sažetak
Nitrogen compounds discharged in the environment can cause several problems such as eutrophication and deterioration of water sources. Furthermore, nitrates can cause hazards to human health by forming nitrosamines and nitrosamides which are found to be potentially carcinogenic compounds [1]. The food process industry generates a large quantity of by-products, which usually have low or no value and represent a possible environmental pollution. Development of inexpensive and effective water treatment chemicals have been of great interest during the last few years. Therefore, bio-based materials, ie. by-products could be utilized in the removal of anions from water. The aim of this work was to remove nitrate from wastewater of the confectionary industry by adsorption/ion exchange process. Chemically modified grape seed anion exchange resin was used in the sorption studies. The modification of grape seeds was carried out using epichlorohydrin, N, N-dimethylformamide, ethylendiamine and trimethylamine [2]. The physico-chemical properties of quaternized resin made from grape seeds (MGS) was analysed using techniques like SEM and FTIR. Batch studies were carried out to optimize the conditions for adsorption: • the concentrations ranges of nitrate were 10 mg/L to 300 mg/L • the pH was adjusted from 2 to 10 using HCl and NaOH • the effect of contact time was studied with nitrate solution of 30 mg/L and 0.2 mg MGS for varying periods of time (2 to 1440 minutes) • the resin doses were varied from 0.05 g to 0.5 g in a 50 mL nitrate solution of 30 mg/L NO3-. The removal efficiency of real wastewater generated from a local confectionary industry containing approximately 30 – 35 mg/L NO3- was about 80%. The nitrate removal capacity of resin from real wastewater with 300 mg/L nitrates was 16.21 mg/g. Langmuir, Freundlich and Dubinin-Raduschkevich adsorption isotherms were used to fit the equilibrium data. The Dubinin-Raduschkevich isotherm gave a better fit than Langmuir or Freundlich isotherm. The values of E (free energy) obtained in Dubinin-Raduschkevich model found to be greater than 14 kJ/mol, indicating the adsorption process as chemical ion-exchange process [3]. The adsorption kinetics followed the pseudo-second order kinetic model with higher correlation coefficient (R2 > 0.995) compared to pseudo-first order kinetic model, suggesting that the adsorption limiting step may be chemisorption. In addition, the results indicate that intraparticle diffusion model was not the sole rate controlling step (C≠0) which indicates that both intraparticle diffusion and boundary diffusion affected the nitrate adsorption on MGS. Modified grape seed was tested in column as well. The resin could only absorb a certain amount of nitrates and therefore the saturation capacity was very low (1.43 mg/g) after first cycle. Other anions present in wastewater had higher affinity for MGS.

Izvorni jezik
Engleski

Znanstvena područja
Prehrambena tehnologija

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