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In this work, novel microbial yeast-decorated zeolitic imidazolate framework-8 (ZIF-8/yeast) composites were successfully synthesized by an in situ growth method and applied in the efficient elimination of Eu(III) from a water medium. The adsorption performances and interaction mechanisms of Eu(III) by ZIF-8/yeast were determined by macroscopic experimental tests under diverse water chemistry conditions. The experimental results indicated that the adsorption performance of Eu(III) on ZIF-8/yeast hybrids could reach equilibrium within 15 min, which conformed to the pseudo-second-order kinetic pattern. The maximum adsorption capacity was 1.09 × 10−3 mol g−1, which was higher than that of a series of adsorbents reported in previousliterature. The interaction mechanism between ZIF-8/yeast composites and Eu(III) was primarily revealed by electrostatic attraction, cation exchange and surface complexation. According to the research, the ZIF-8/yeast is considered a preferable adsorbent for the highly efficient purification and elimination of trivalent lanthanides from radioactive wastewater. [ABSTRACT FROM AUTHOR]

To improve the accuracy of an industrial 6-DOF robot, this paper proposes a new calibration method based on a line structured light measurement system. The line structured light measurement system mounted on the end-effector is used as a tool to acquire the three-dimensional coordinate information of the centre of a standard sphere. Hand-eye calibration is used to establish the transformation between the robot and the measurement system. A combined kinematic model that includes both the kinematic parameters of the robot and the initial hand-eye relationship is established by applying the modified Denavit and Hartenberg (MDH) model. An error model is derived based on the principle that the coordinate of the sphere centre is invariant in the base frame of the robot. Consequently, the errors in the kinematic parameters of the robot and the hand-eye relationship can be identified by substituting the measurement results and the original parameters of the robot into the error model. The results of the simulations and experiments show that the accuracy of the robot is significantly improved by implementing the proposed calibration method. The proposed method is effective, simple, time-saving and low-cost and is therefore a suitable candidate for on-site calibration of industrial robots. [ABSTRACT FROM AUTHOR]

Comprehension the extent and rate of U(VI) adsorption on some mineral surfaces are significant to predict their migration and transformation properties in the environmental systems. Herein, iron oxides particles supported reduced graphene oxide composites (MRGO) were successfully synthesized by in-situ chemical precipitation approach. The MRGO composites which illustrated high saturation magnetization could be likely separated using an external magnet. The experimental data illustrated that U(VI) ions could be interacted with MRGO composites through different interaction mechanisms depending on different environmental conditions. The adsorption kinetic results can be well simulated using the pseudo-second-order pattern. The pH-dependent adsorption behavior illustrated an favorable pH value of 7.5 for removal of U(VI) ions using MRGO composites. Furthermore, the adsorption regeneration of MRGO composites in simulated wastewater disposal systems was tested. Based on above mentioned, it was clear that MRGO composites could be potentially used as adsorbent for removal of actual U(VI)-bearing wastewaters. [ABSTRACT FROM AUTHOR]

Retraction of 'Sequestration and speciation of Eu(III) on gamma alumina: role of temperature and contact order' by Yawen Cai et al., Environ. Sci.: Processes Impacts, 2015, 17, 1904–1914, https://doi.org/10.1039/C5EM00412H. [ABSTRACT FROM AUTHOR]

Extraction of radionuclide contaminants from wastewater systems has recently drawn widespread attention, and then developing a novel and green extracting technology has also become an enormous challenge. Herein, a facile hydrothermal method was employed to fabricate cobalt-incorporated cryptomelane-type manganese oxide molecular sieve (Co-OMS-2) for extraction Eu(III) from wastewater under diverse experimental conditions. All kinds of characterized techniques, such as SEM, TEM, XRD, FTIR, BET, EDS and XPS had verified the qualified synthesis process and splendid structural features of the Co-OMS-2. The maximum adsorption capacity of Co-OMS-2 was 7.62 × 10−4 mol/g for Eu(III) at 298 K, which was superior than primarily traditional materials reported previous literatures. The high adsorption capacity of Eu(III) onto Co-OMS-2 was primarily attributed to high specific surface area and abundant surface functional groups, and the interactions were mainly contributed to strong surface complexation and electrostatic attraction. Under the condition of low pH, the outer-sphere surface complexation and cation exchange were primary mechanisms to Eu(III) adsorption onto Co-OMS-2 composites, while inner-sphere surface complexation was mainly assigned to Eu(III) adsorption onto Co-OMS-2 under the high pH sections. The Co-OMS-2 composite achieved equilibrium in a relatively short time, and this excellent performance was conducive to the treatment of Eu(III) under the extreme emergency conditions. In view of the extraordinary adsorption capacity and recycled reusability, the Co-OMS-2 composites can be as prospective adsorbents adopted for the extraction of Eu(III) in real wastewater management. • Oriented functionalization of Co-OMS-2 was successfully synthesized. • The maximum adsorption capacity of Eu(III) by Co-OMS-2 was 7.62 × 10−4 mol/g. • Co-OMS-2 displayed remarkable stability in the elimination of radionuclides. • The surface complexation and ion exchange were the main interaction mechanisms. [ABSTRACT FROM AUTHOR]

The speciation, migration and transport of radionuclides in the environment are significantly influenced by their interactions with the natural minerals and humic substances therein. In view of this, the effect of temperature and contact order on the sorption behaviors of trivalent Eu(iii) in the γ-Al2O3/Eu(iii) and γ-Al2O3/HA/Eu(iii) systems was studied using batch experiments and the extended X-ray absorption fine structure spectroscopy (EXAFS) technique. The endothermic sorption behavior of Eu(iii) in the γ-Al2O3/Eu(iii) systems was induced by the hydrolysis reaction of Eu(iii) in solution and the complexation of Eu(iii) with the γ-Al2O3 surface sites. The endothermic sorption of Eu(iii) in the γ-Al2O3/HA/Eu(iii) systems was attributed to the endothermic binding of HA on γ-Al2O3 and the endothermic complexation between Eu(iii) and HA. EXAFS analysis suggested the formation of type B ternary complexes and their thermodynamic stability improves with rising temperature. The different sorption percentages under various contact orders were closely related to the binding mode of Eu(iii) on the exposed γ-Al2O3 surfaces or the γ-Al2O3/HA colloids. The findings obtained herein are important to evaluate the security of the radioactive waste repository and predict the fate of trivalent actinides (e.g., Am(iii), Cm(iii), Pu(iii), etc.) near the geological repository. [ABSTRACT FROM AUTHOR]

To better understand the application of kaolinite as an adsorbent for the decontamination of Ni(II) from radionuclide contaminated aqueous systems, herein, the sorption behavior of radionuclide Ni(II) on kaolinite as a function of contacting time, pH, coexistent electrolyte ions, adsorbent concentration, fulvic acid and humic acid was investigated using batch technique. At low pH values, ion exchange and/or outer-sphere surface complexation was the main mechanism of Ni(II) sorption on kaolinite, whereas, the sorption of Ni(II) was dominated by inner-sphere surface complexation at high pH values. The presence of different electrolyte ions can enhance or inhibit the sorption of Ni(II) on kaolinite to some extent. The Langmuir and Freundlich models were used to simulate the sorption isotherms of Ni(II) at three different temperatures of 288, 313 and 338 K. The thermodynamic parameters (i.e., Δ S°, Δ H°, and Δ G°) calculated from the temperature-dependent sorption isotherms indicated that the sorption reaction of Ni(II) on kaolinite was endothermic and spontaneous. The findings in this present study demonstrates that the kaolinite can be used as a cost-effective adsorbent for the solidification and pre-concentration of Ni(II) from large volumes of aqueous systems. [ABSTRACT FROM AUTHOR]

In this study, the removal of radionuclide Co(II) from wastewater by Ca-rectorite was studied as a function of various environmental parameters such as contact time, pH, ionic strength, coexisting electrolyte ions, humic substances (HS) and temperature under ambient conditions. The results indicated that the sorption of Co(II) on Ca-rectorite was strongly dependent on pH and ionic strength. The Langmuir and Freundlich models were used to simulate the sorption isotherms of Co(II) at three different temperatures of 298.15, 318.15 and 338.15 K. The thermodynamic parameters ( $$ \Updelta H^{0} ,\,\Updelta S^{0} $$ and $$ \Updelta G^{0} $$) calculated from the temperature-dependent sorption isotherms indicated that the sorption process of Co(II) on Ca-rectorite was spontaneous and endothermic. At low pH, the sorption of Co(II) was dominated by outer-sphere surface complexation and ion exchange with Ca/H on Ca-rectorite surfaces, whereas inner-sphere surface complexation was the main sorption mechanism at high pH. From the experimental results, it is possible to conclude that Ca-rectorite has good potentialities for cost-effective disposal of radiocobalt bearing wastewaters. [ABSTRACT FROM AUTHOR]

High background electrolyte and natural organic matter are favorable to migration of hazardous radionuclides in geochemical repository. Herein, Ca–Mg–Al layered double hydroxide coated onto graphene oxide (Ca–Mg–Al LDH/GO) composites were successfully synthesized, characterized and adopted to decontaminate Eu(III) and fulvic acid (FA) under diverse experimental conditions. Diverse concentration gradients and different addition sequences on Eu(III) and FA were also obtained, which revealed different interaction mechanisms. The experimental results displayed that the coexistence of FA and Eu(III) respectively promoted adsorption performance of Eu(III) and FA under the ternary systems. The acquired Ca–Mg–Al LDH/GO composites were adopted to remove Eu(III) and FA, which further illustrated excellent chemo-physical stability and adsorption capacity of 1.12 × 10−3 mol/g and 3.54 × 10−4 mol/g, respectively. The remarkable adsorption performances of Ca–Mg–Al LDH/GO were confirmed through kinetic procedures and depending-temperature isotherms, illustrating that the kinetics processes were simulated using pseudo-second-order pattern, and the adsorption isotherms were splendidly simulated using Langmuir pattern. XPS spectrum analysis revealed that these containing oxygen groups took significant part in the restricting of Eu(III) and FA onto the surfaces of Ca–Mg–Al LDH/GO composites. In view of experimental results, the Ca–Mg–Al LDH/GO composites can be as potential adsorbents with availably recycled reusability for the decontamination of Eu(III) and FA from nuclear fuel partition or nuclear wastewater systems. • Ca–Mg–Al LDH/GO composites were successfully fabricated. • Oxygen-including groups of Ca–Mg–Al LDH/GO played important role in removal of Eu(III) and FA. • The removal mechanism of Eu(III) was controlled via surface complexation. • Ca–Mg–Al LDH/GO composites can be applied to effective disposal of Eu(III) and FA from wastewater. [ABSTRACT FROM AUTHOR]