| 1. |
- Kumar, Rakesh, et al.
(författare)
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State-of-the-art of research progress on adsorptive removal of fluoride-contaminated water using biochar-based materials : Practical feasibility through reusability and column transport studies
- 2022
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 214
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Tidskriftsartikel (refereegranskat)abstract
- Fluoride (F-) is one of the essential elements found in soil and water released from geogenic sources and several anthropogenic activities. Fluoride causes fluorosis, dental and skeletal growth problems, teeth mottling, and neurological damage due to prolonged consumption, affecting millions worldwide. Adsorption is an extensively implemented technique in water and wastewater treatment for fluoride, with significant potential due to efficiency, cost-effectiveness, ease of operation, and reusability. This review highlights the current state of knowledge for fluoride adsorption using biochar-based materials and the limitations of biochar for fluoride-contaminated groundwater and industrial wastewater treatment. Biochar materials have shown significant adsorption capacities for fluoride under the influence of low pH, biochar dose, initial concentration, temperature, and co-existing ions. Modified biochar possesses various functional groups (-OH, -C=C, -C-O, -CONH, -C-OH, X-OH), in which enhanced hydroxyl (-OH) groups onto the surface plays a significant role in fluoride adsorption via electrostatic attraction and ion exchange. Regeneration and reusability of biochar sorbents need to be performed to a greater extent to improve removal efficiency and reusability in field conditions. Furthermore, the present investigation identifies the limitations of biochar materials in treating fluoride-contaminated drinking groundwater and industrial effluents. The fluoride removal using biochar-based materials at an industrial scale for understanding the practical feasibility is yet to be documented. This review work recommend the feasibility of biochar-based materials in column studies for fluoride remediation in the future.
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| 2. |
- Li, Changbai, et al.
(författare)
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Separation and concentration of rare earth elements from wastewater using electrodialysis technology
- 2021
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Ingår i: Separation and Purification Technology. - : ELSEVIER. - 1383-5866 .- 1873-3794. ; 254
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Tidskriftsartikel (refereegranskat)abstract
- Rare earth elements (REEs) including Scandium (Sc) are critical raw materials which are greatly needed in the advancement of many modern technologies. Due to the problems associated with the primary extraction of mining ores, the procurement of Sc and REEs from the secondary resources are currently explored adopting the principle of sustainability and circular economy. Herein, for the first time, the Electrodialysis (ED) technology based on electrochemical membrane separation process is successfully applied to separate and concentrate REEs from the diluted aqueous system. The overall performance of ED process in the recovery of Sc3+ ions from the wastewater was assessed by applied current, voltage, feed concentration, feed pH, co-ion competition and the overall energy consumption of the process. The REE recovery using the ED process was subjected to systematic investigations using both chronopotentiometric and chronoamperometric analyses. The results showed that ED process could be very promising in the recovery of Sc3+ ions (similar to 99.52% removal) from the diluted wastewater, consuming the energy of only 0.26 kWh/m(3) when operated at constant voltage mode (Sc3+ concentration of 20 ppm, pH 4, 1 h).
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| 3. |
- Valimaa, Alpo, et al.
(författare)
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Multiphonon Transitions in a Quantum Electromechanical System
- 2022
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Ingår i: Physical Review Applied. - 2331-7019. ; 17:6
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Tidskriftsartikel (refereegranskat)abstract
- Studies of micromechanical and acoustic modes in the quantum regime have shed light on quantum properties of massive objects. Integrating these systems into superconducting circuits shows great promise for applications as quantum memory elements, bosonic codes, or in frequency conversion. To this end, investigation of nonclassical properties of acoustic degrees of freedom is critical also for applications. Here, we investigate a strongly driven system consisting of a transmon qubit interacting with a highovertone bulk acoustic resonator. We observe multiphonon transitions, which enable mapping the energy landscape in the coupled system. At a high driving amplitude comparable to the qubit-oscillator coupling, we observe a shift of the multiphonon spectral lines, reminiscent of Stark shift, which is explained using a simple model. Our work thus also provides insight in multiquanta transitions in other qubit-oscillator systems, not limited to acoustics or circuit quantum electrodynamics.
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