Separation scientists and radiochemists aim to recover valuable long-lived radionuclides from high-level nuclear waste solution before its safe geological disposal. In last few years, researchers have exploited biosorption for nuclear waste management as an alternative to conventional liquid–liquid separation techniques. This review outlines various methods employed for the preparation of biosorbents. Importantly, nuclear waste treatment using biosorbents has been discussed in detail along with adsorption mechanisms. The main objective of this review is to provide vital information on the developments that have been made so far in the domain of biosorption, exclusively for nuclear waste management

Biosorption-an alternative method for nuclear waste management: A critical review

Uranium (VI)-containing water has been recognized as a potential longer-term radiological health hazard. In this work, the sorptive potential of sunflower straw for U (VI) from aqueous solution was investigated in detail, including the effect of initial solution pH, adsorbent dosage, temperature, contact time and initial U (VI) concentration. A dose of 2.0 g L−1 of sunflower straw in an initial U (VI) concentration of 20 mg L−1 with an initial pH of 5.0 and a contact time of 10 h resulted in the maximum U (VI) uptake (about 6.96 mg g−1) at 298 K. The isotherm adsorption data was modeled best by the nonlinear Langmuir–Freundlich equation. The equilibrium sorption capacity of sunflower straw was observed to be approximately seven times higher than that of coconut-shell activated carbon as 251.52 and 32.37 mg g−1 under optimal conditions, respectively. The positive enthalpy and negative free energy suggested the endothermic and spontaneous nature of sorption, respectively. The kinetic data conformed successfully to the pseudo-second-order equation. Furthermore, energy dispersive X-ray, fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy demonstrated that U (VI) adsorption onto sunflower straw was predominantly controlled by ion exchange as well as complexation mechanism. The study revealed that sunflower straw could be exploited for uranium remediation of aqueous streams as a promising adsorbent.

Biosorption behaviors of uranium (VI) from aqueous solution by sunflower straw and insights of binding mechanism

Competitive adsorption of toxic metals on bentonite and use of chitosan as flocculent coagulant to speed up the settling of generated clay suspensions

Amidoxime modified Trametes trogii pellets were prepared by sequential reaction of fungal surfaces with glutaraldehyde, diaminomaleonitrile and hydroxylamine. Maximum biosorption capacities of the modified and native pellets were found to be 447.4 and 238.2 mg U(VI) g−1 fungal pellets, respectively. Biosorption equilibriums were established in about 45 min and the correlation regression coefficients show that the adsorption process can be well-defined by Langmuir equation. The biosorption of U(VI) ions was well described by the pseudo-second order kinetic model. The variations in enthalpy and entropy for the biosorbents were also calculated.

Amidoxime functionalized Trametes trogii pellets for removal of uranium(VI) from aqueous medium

Accumulation of Co(II) and Eu(III) by the mycelia of Aspergillus niger isolated from radionuclide-contaminated soils

Removal and recovery of uranium from dilute aqueous solutions by dead fungal biomass (Pleurotus mutilus) have been studied by biosorption. The parameters that affect the uranium(VI) adsorption, such as: pH solution, temperature, biomass particle size and speed of stirring have been investigated and optimized. The experimental data were analyzed using pseudo-first-order and pseudo-second-order equations. The Freundlich and Langmuir adsorption models have been used for the mathematical description of the adsorption equilibrium. The maximum uranium biosorption capacity has been calculated. The value obtained (636.9 mg g−1) showed that P. mutilus is a good adsorbent. Also, the chemical bands involved in uranium link have been identified. We have applied this biosorption to actual waste uranium leachate, the results are satisfactory and promising.

http://dspace.univ-bouira.dz:8080/jspui/bitstream/123456789/3876/1/Characterization%20and%20properties%20of%20Pleurotus%20mutilus%20fungal%20biomass%20as%20adsorbent%20of%20.pdf

Ziane Kamel

Papers

Characterization and properties of Pleurotus mutilus fungal biomass as adsorbent of the removal of uranium(VI) from uranium leachate