Vol.:(0123456789) 1 3 Journal of Radioanalytical and Nuclear Chemistry https://doi.org/10.1007/s10967-019-06877-z Uranium(VI) biosorption by sugar beet pulp: equilibrium, kinetic and thermodynamic studies M. Nuhanović 1  · M. Grebo 1  · S. Draganović 1  · M. Memić 1  · N. Smječanin 1 Received: 9 September 2019 © Akadémiai Kiadó, Budapest, Hungary 2019 Abstract Native and chemically modifed sugar beet pulp were used as a biosorbents for removal of uranium(VI) from the aqueous solution. The efects on the uranium(VI) uptake such as solution pH (2–9), adsorbent amount (50–500 mg), contact time (0–180 min), temperature (293–323 K) and initial concentration (20–60 mg U L −1 ) were studied. The obtained maximum adsorption capacities according to Langmuir isotherm model for native and modifed sugar beet pulps were 20.45 and 19.80 mg g −1 , respectively. Additionally, pseudo-second order kinetic model best ftted the experimental data. Keywords Uranium(VI) · Sugar beet pulp · Biosorption · Kinetic Introduction Due to its radioactivity and chemical toxicity at very low concentrations uranium is extremely dangerous for the envi- ronment and human health. Increasing amounts of wastewa- ter containing uranium are produced annually from various activities such as exploration and processing of uranium, mining industry, nuclear industry associated activities, industries that utilize radioisotopes and geological disposal of radioactive waste [1, 2]. In the environment uranium is mainly present in two oxidation states U(IV) and U(VI). Among this two uranium species, U(IV) is less soluble and occurs under strongly reducing conditions and U(VI) appears as a mobile, hydrated uranyl UO 2 2+ ion [3, 4]. Some of conventional methods for removal of uranium from the wastewater are chemical precipitation, co-precipitation, elec- trochemical treatment, ion exchange, membrane processes, solvent extraction and adsorption [5–12]. All listed methods have a lot of limitations, such as incomplete metal removal, high energy depletion, limiting pH and concentrated liquid wastes [13, 14]. Among listed methods, the most promising method for uranium removal is adsorption due to its simplic- ity, applicability, high selectivity and capacity. Recently a lot of research is focused on development of new innovative adsorbents with special emphasis on biosorbents. Based on the use of biomass as an adsorbent, biosorption of diferent types of metal ions including uranium from aqueous solu- tions is considered as a very promising procedure. Com- pared to other methods, biosorption is more economical, eco-friendly, energy saving, has a wide working range of pH and temperature, minimal volume of disposable sludge, high efciency, selectivity, moreover, once used biomass can be reused in multiple cycles depending on its capacity [15–18]. A lot of diferent adsorbents, such as pummelo peel [19], Eucalyptus citriodora distillation sludge [20], Citrobacter freudii, a bacterium [1], Catenella repens, a red alga [21], pollen pini [22], Bangia atropurpurea, a red alga [23], algi- nate beads [24], wood powder and wheat straw [4], poly- aniline coated magnetic carboxymethylcellulose [25], silica particles grafted with polyacrylonitrile beads [26] etc. were considered for the removal of uranium ions from the aqueous solution, but there are only a few studies in which removal of uranium and other radionuclides were explore by adsorp- tion on agricultural waste [27–31]. Agricultural waste as a low-cost biosorbent is of great interest for treatment and removal of toxic pollutants due to its several advantages such as specifc chemical composition (i.e. hemicellulose, cellulose, lipids, lignin, sugar, pectins etc.) containing a lot of acidic functional groups (i.e. carboxylic and hydroxy) which can bind pollutant ions very efectively. Additional advantages are availability, high efciency as well as easy to modify with diferent chemical reagents [13, 32]. Moreover, * M. Nuhanović mirzanuhanovic1.0@gmail.com 1 Department of Chemistry, Faculty of Sciences, University of Sarajevo, Zmaja od Bosne 33-35, 71 000 Sarajevo, Bosnia and Herzegovina