[en] When Penicillium digitatum Saccardo cultures are exposed to aqueous solutions containing soluble uranium salts, considerable amounts of this element are accumulated in the fungal mycelium. The accumulated uranium is retained after thorough rinsing with distilled water but is removed by alkali carbonate solutions. Analysis of thick sections (0.5 μm) of the fungal hyphae with TEM, after incubation in UO₂Cl₂ solutions of varying concentrations under both light and dark conditions, revealed conspicuous crystal-like deposits in UO₂Cl₂-exposed hyphae, but none in the control hyphae. Thick sections were necessary for crystal visualization. Using energy-dispersive X-ray analysis, uranium was detected as the only heavy element in these crystals. Uranium crystal biosorption was localized on the outside surface of the hyphal cell wall (following short exposures to relatively low uranium concentrations) or inside the cell wall (following long exposure to relatively high uranium concentrations). In some cases, crystal-like deposits of uranium salts were located on the outside surface as well as inside the cell. (author)

[en] The uptake of lanthanide elements by naturally abundant materials, is a matter of great economic and environmental interest. This study is an exploration of the potential utilization of malt spent rootlets (MSR), which are by-products of malting process, for a cost effective pre-concentration of Eu(III). The effect of solution pH, contact time and initial concentration under constant ionic strength and temperature were studied. Kinetic data were applied to pseudo-first, second order and Elovich equations, as well as intra-particle diffusion model. Pseudo-second order and Elovich equation seem to fit our data equally well, whereas diffusion contributes to the whole process. Equilibrium data were evaluated using Langmuir, Freundlich and Dubinin-Radushkevich equations. According to Langmuir model, which fits the data better, europium maximum capacities for MSR and active carbon were found 156 and 86 mg/g respectively, indicating that MSR is a promising biosorbent. (author)

[en] Plumb shell was used to prepare an adsorbent for biosorption of lead ions in aqueous solution at 25 degree C. The adsorption capacity of the adsorbent at equilibrium was found to increase from 2.8 to 49.0 mg/g with an increase in the initial lead ion concentration from 50 to 200 mg/L. Using the equilibrium and kinetics studies, isotherm of the lead ions on the biosorbent was determined and correlated with common isotherm equations. The equilibrium data for lead ion adsorption fitted well into the Freundlich equation, with a value of 0.76 (R2 = 0.9), with distribution coefficient of 4.90. The biosorption of lead ions on the adsorbent from plumb shells could best be described by the pseudo-second-order equation. The kinetic parameters of this best-fit model were calculated and discussed. (author)

[en] Posidonia oceanica (L.) Delile is an important endemic sea plant in the Mediterranean Sea. Its dead leaves are accumulated in the beaches and cause bad view and also odour in the touristical beaches. Therefore, these dead leaves accumulated on the beaches are collected and then burned in some beaches in Turkey. In the present study, the adsorption between dead leaves and uranium were studied in the aqueous solutions. The adsorption data obeyed the pseudo-second order kinetics. Among the studied isotherms, the data were well in line with the Freundlich and Dubinin-Raduschkevich models and the maximum adsorption capacities obtained from these models were found as 5.67 and 9.81 mg g^-1, respectively. Negative values of Gibbs free energy showed that the adsorption was in spontaneous nature. In conclusion, the dead leaves of P. oceanica from touristic beaches might be collected and evaluated as a low-cost adsorbent for removal of uranium(VI) from aqueous solutions. (author)

[en] This article focuses on the efficient removal of iodate by pomelo peel, a low-cost biosorbent. The Langmuir and Pseudo-first-order model are the best fit models. The response surface methodology (RSM) was also used to find the optimal experimental factors and their correlations. The maximum adsorption capacity can reach 6.91 mg g^-1 under the optimal factors. The dominant mechanism is physical adsorption and the oxygen-containing groups of pomelo peel play a decisive role in adsorption. Pomelo peel could be an efficient, economical and eco-friendly iodate adsorbent and RSM is valuable in the research of radioactive waste treatment. (author)

[en] The influence of cations and anion in solution on biosorption of uranium is investigated. The experimental results show that the sorption capacity of uranium is greatly inhibited by the cations such as Fe³⁺, Fe²⁺, Al³⁺, Pb²⁺, Cu²⁺, Zn²⁺, Cr³⁺. The sorption capacity of uranium is decreased by 25%-85%. The effect of SO₄^2- on biosorption of uranium is weak

[en] Simultaneous adsorption of thorium, europium, cerium, and neodymium by immobilized tannic was studied at different ph values. Tannic materials have excellent ability to adsorb selectively thorium at pH 5. The rest of the elements could be isolated in group at pH 7

[en] During the transportation of oil, various oil-spill incidents are reported. The utilization of oil sorbents for the treatment of oil spills is a promising approach among the all-existing solutions. Nonbiodegradability and non-renewability are the two major issues in the case of synthetic oil sorbents. In this review, the use of biodegradable polymers for oil-spill cleanup is highlighted. In each section, the biodegradable materials and modifiers used, the method applied for a modification, the contact angle after modification, sorption capacities, and the reusability of developed biodegradable sorbents are extensively discussed. Mechanisms of biodegradation of biopolymers are also discussed. The manuscript also incorporates the recent developments in the fabrications of advanced sorbents with sustainable approaches along with challenges associated with current sorbents and future prospects. (© 2023 Wiley‐VCH GmbH)

[en] Azolla imbircata dry powder (Ai-dp) was prepared by collecting wild Azolla imbircata, drying and grinding. SEM, FTIR and XPS have been used to characterize it. Batch biosorption experiments studied pH, contact time, initial U(VI) concentration, adsorbent dosage and temperature effects on U(VI) biosorption. These results indicated that the maximum biosorption capacity was 4.55 mg L^-1 under conditions of 303 K, pH 2.0, initial U(VI) concentration 15 mg L^-1 and adsorbent dosage 3.75 g L^-1. The biosorption process fit pseudo-second-order kinetics and Langmuir isotherm, it showed the adsorption process was monolayer chemisorption. The thermodynamic fitting results showed the adsorption process was spontaneous and exothermic. (author)

[en] Uranium pollution is a severe problem worldwide. Biosorption has been proposed as one of the most promising technologies for the removal of uranyl cations. Here we report on the adsorption behavior of uranium(VI) [U(VI)] on Bacillus licheniformis biomass to explore the potentiality of its application in uranium contamination control. The adsorption equilibrium, adsorption kinetics, and effects of temperature, pH and initial biosorbent dosage on the adsorption equilibrium were investigated in detail through batch experiments. The adsorption process is pronouncedly affected by the solution pH and the optimum pH range should be 4.5-5.0.Temperature range from 25 to 45 deg C has a certain effect on the rate of biosorption, but little effect on the equilibrium adsorption capacity. The U(VI) percentage removal increased concurrently with increasing biomass dosage, whereas the adsorption capacity decreased. The process follows the Langmuir isotherm model. The adsorption kinetics data were fitted very well by the pseudo-first-order rate model. Finally, the calculation results of thermodynamic constant (ΔG < 0) and kinetic constant (E_a = 9.98 kJ/mol) reveal that the adsorption process can be identified as a spontaneous chemical process. The present results suggest that B. licheniformis has considerable potential for the removal of uranyl from aqueous solution. (author)