One-step Regeneration Research Articles

Innovative research on one-step regeneration and reduction of saturated desulfurization coke: Reactivating desulfurization performance and sulfur recovery

Current advancements in flue gas desulfurization have highlighted the efficacy of activated coke (AC) as an SO2 adsorbent, leveraging sulfur resources. Despite its success, challenges such as lengthy processing and logistics for sulfuric acid storage and transport limit its widespread use. This research explores an innovative approach: powder saturated AC (SAC) achieves rapid temperature rise and one-step regeneration coupled reduction in a drop-tube reactor. Findings reveal that SAC undergoes primary regeneration at 450–650 ℃, converting adsorbed sulfur compounds into gaseous SO2. However, issues like incomplete active site recovery and surface oxidation reduce the re-adsorption capacity of regenerated AC. At 750–950 ℃, a concurrent regeneration and reduction phase converts desorbed SO2 into elemental sulfur. Carbothermal reduction during this phase enhances microporous structure development, lowers oxygen content, increases edge defects, promotes sulfur doping, and boosts SO2 re-adsorption efficiency. This study provides practical insights and a conceptual framework to refine desulfurization processes and optimize resultant products.

Enabling one-step regeneration of LiBH4 with self-sustaining hydrogen in its spent fuel – One pathway to storing renewable hydrogen

LiBH4 (LB in short) with a hydrogen capacity as high as 18.5 wt% and a low molecular weight (21.78 g mol−1) is among the most promising candidates for the hydrogen-based economy. However, current major technologies in (re)generation of LB rely heavily on energy-intensive processes, which greatly prohibits practical scaling-up of applications. Here we report a sustainable and effective approach to (re)generate LB via converting renewable H+ in crystalline water into H-, achieving a desirable yield of ∼50%. This one-step synthesis method relies on the reaction between spent fuels, specifically LiBO2·xH2O, and Mg-based alloys to form LB under ambient atmosphere. Notably, our approach surpasses the efficiency of other conventional method, such as LiH-B-H2 and MgH2-LiBO2 systems, which not only bypasses the energy-intensive dehydration procedure of LiBO2·xH2O (∼470 ℃) but also eliminates the use of costly hydrides or high-pressure H2. Our findings indicate that Mg participated in the regeneration process prior to Al in Mg-Al alloys and [BH4]- is gradually evolved from other intermediate species [BHx(OH)4-x]- (x = 0, 1, 2, 3). By combining hydrogen release and efficient storage of hydrogen-rich substrate in a closed materials cycle, this study may shed light on a promising step toward application of renewable hydrogen in a fuel cell-based hydrogen economy.

One-step regeneration and upgrading of spent LiFePO4 cathodes with phytic acid.

The regeneration and upgrading of spent LiFePO4 cathodes (S-LFP) were achieved via a one-step hydrothermal treatment. The reducing effect of phytic acid could restore the degraded structure associated with an aqueous Li source. Meanwhile, Li ions are easily chelated by phytic acid groups, and a Li3PO4 coating layer could be formed to reconstruct the surface of the LFP. The regenerated LFP exhibits faster reaction kinetics, larger high-rate charge/discharge capacity, and better cycling performance than commercial LFPs, suggesting that our proposed strategy is a promising technology for the recovery of spent cathode materials.

Unravelling Li-ion Storage Capability of Cobalt Oxide Anode Recovered from Spent LiCoO2 Cathode via Carbothermal Reduction

With the advent of globalization, the upsurge of lithium-ion battery (LIB) production and generation of spent batteries impose a severe threat as hazardous e-waste and resource sustainability of crucial elements like cobalt and lithium. Herein, we propose one-step regeneration of cobalt oxide (RCO) from cycled LiCoO2 (LCO)-type cathode via carbon anode-assisted reduction. The inherent structural changes resulting in high irreversibility are minimized in conversion-type mixed-phase recycled cobalt oxide anode due to less Li-ion consumption and stable SEI formation during initial cycles. Replacement of conventional Cu-foil current collector with carbon-fiber (CF) based freestanding electrode further enhances the Li-ion storage capacity with overall active material utilization, accommodating volume changes in the internal void spaces and providing mechanical stability. Electrochemistry reveals that RCO@CF and RCO@Cu deliver an initial discharge capacity of 3800 mAh g−1 and 1432 mAh g−1 at 30 mAg−1 with 77% and 64% coulombic efficiency that becomes ∼97% in the following cycles. Besides, RCO@CF shows an average discharge capacity of 730 mAh g−1 at 300 mA g−1 over 300 cycles, which is ∼2.7 times that of recycled graphite anode (270 mAh g−1). The sustainable recycling strategy described herein rejuvenates the cycled LCO-type cathode as an appealing anode material for LIBs.

A one-step regeneration method in-situ for deactivated aluminum-based lithium adsorbent used in high Mg2+/Li+ brines

Excessive Li+ deintercalation from the difficulty of precisely controlling desorption would lead to the deactivation of lithium/aluminum layered double hydroxide (Li/Al-LDH) as the aluminum-based lithium adsorbent in brines. In this study, a novel one-step regeneration method was established to in-suit recover the deactivated Li/Al-LDH and was verified to be universally applicable for Li/Al-LDH with different forms and deactivation degrees. It was witnessed the powdery and granulated Li/Al-LDH could be regenerated in less than 5 min and 2 h, respectively. The in-situ regeneration of deactivated granules was achieved in the fixed bed. Besides, high temperature, high Li+ concentration, alkalinity, and high ionic strength were conductive to the structural transformation of deactivated adsorbents from gibbsite (γ-Al(OH)3) to active Li/Al-LDH and restore to normal Li+ adsorption capacity on account of the intercalation reaction of Li+ in gibbsite. Moreover, the regeneration mechanism was further illustrated in detail that Cl− and water molecules entered the interlayer as Li+ was inserted into the vacancies of deactivated adsorbent laminates to reconstruct Li/Al-LDH structure. This efficient regeneration method resolves the deactivation of Li/Al-LDH adsorbents, and is expected to be applied in the industrial lithium extraction to completely solve the insufficient long-term cycle stability caused by excessive desorption.

One-Step Electrical Insulating Oil Regeneration on Electret PVDF/BaTiO3 Composite Nanofibers

Insulating oil is a pivotal component of power transformers, but it suffers from aging byproducts during service operation. The aging byproducts from the degradation of oil insulation tend to induce insulation failure, which poses a significant threat to the security of the power grid. Therefore, the regeneration of insulating oil is required to prolong the useful life of insulating oil and hence be of economic and ecological interests. Typical in-use oil regeneration routes employ multi-step procedures. In this work, a one-step regeneration method using a PVDF/BaTiO3 composite membrane is proposed. BaTiO3 endows the composite membrane with improved hydrophobicity and an electret state. The regeneration performance of the PVDF/BaTiO3 nanofiber membrane was assessed by considering the acid value, moisture content, dielectric loss factor tan δ, and the AC breakdown voltage of the refreshed oil. The test results showed that the filtration efficiencies toward formic acid and moisture were up to 77.5% and 60.6%, respectively. Moreover, the dielectric loss factor tan δ of the refreshed oil decreased evidently at a power frequency, and the AC breakdown voltage rose from 23.7 kV to 38.9 kV. This suggests that the PVDF/BaTiO3 composite membrane may be employed efficiently, and it minimizes aging byproducts via the one-step filtration.

Research on the one-step regeneration of sugarcane in KK3 variety (Saccharum officinarum L.) in vitro

The research has successfully created the formula for direct regeneration medium of sugarcane variety KK3. In detail, the most suitable medium for direct regeneration from young leaf rolls of sugarcane variety KK3 was RE2 (MS + 5 mg/l α-NAA + 1 mg/l Kinetin), the regeneration rate was 25.27%, the number of shoots formed/1.0 g of young leaf rolls reached 11.56 shoots. The study showed that the position of the young leaf rolls cuttings suitable for direct regeneration was the cuttings located from 2-6 cm away from the growth apex. The shoot regeneration rate reached 25.40%, the regenerating samples were 25.40%, good yield, and a high rate of multiple shoot formation. When using plant cuttings with a thickness of 1 cm, the highest regeneration rate was 25.58%, and the ability to form multiple shoots was high. Pre-cultivation time had a positive effect on the ability to regenerate shoots directly from young leaf coils of sugarcane variety KK3. When conducting pre-cultivation in four days will help increase the regeneration ability of the sugarcane variety, reaching 47.49%. MS medium + 5 mg/l α-NAA + 1 mg/l Kinetin supplemented with 30% coconut water showed the highest regeneration ability, reaching 52.95%, number of shoots reaching 52.33 shoots/1 g of young leaf rolls.

Efficient Direct Recycling of Degraded LiMn2O4 Cathodes by One-Step Hydrothermal Relithiation.

Due to the large demand of lithium-ion batteries (LIBs) for energy storage in daily life and the limited lifetime of commercial LIB cells, exploring green and sustainable recycling methods becomes an urgent need to mitigate the environmental and economic issues associated with waste LIBs. In this work, we demonstrate an efficient direct recycling method to regenerate degraded lithium manganese oxide (LMO) cathodes to restore their high capacity, long cycling stability, and high rate performance, on par with pristine LMO materials. This one-step regeneration, achieved by a hydrothermal reaction in dilution Li-containing solution, enables the reconstruction of desired stoichiometry and microphase purity, which is further validated by testing spent LIBs with different states of health. Life-cycle analysis suggested the great environmental and economic benefits enabled by this direct regeneration method compared with today's pyro- and hydrometallurgical processes. This work not only represents a fundamental understanding of the relithiation mechanism of spent cathodes but also provides a potential solution for sustainable and closed-loop recycling and remanufacturing of energy materials.

Recycling of LiCoO2 cathode material from spent lithium ion batteries by ultrasonic enhanced leaching and one-step regeneration

A novel process for recycling of spent LiCoO2 cathode materials has been developed. The novel process comprises an ultrasonic enhanced leaching and one-step regeneration of LiCoO2 materials with spray drying method. The ultrasonic is novelly applied for effectively improving leaching process of spent LiCoO2 materials in the system of DL-malic acid and H2O2. The leaching efficiencies of 98.13% for Li and 98.86% for Co were presented under the optimal condition of 1.5 mol/L DL-malic acid with 3 vol% H2O2, the solid/liquid ratio of 4 g/L, ultrasonic power of 95 W, temperature of 80 °C and leaching time of 25 min. Based on kinetic analysis, the ultrasonic enhanced leaching process is mainly controlled by the diffusion control model. Meanwhile, the product of Co(C4O5O5)2 formed on particles surface of spent LiCoO2 materials during ultrasonic enhanced leaching process, which is provided from reaction mechanism analysis of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Finally, the regenerated LiCoO2 materials are regenerated in one step by spray drying from leaching solution, which present good electrochemical performance.

A DFT study of the regeneration process of zinc porphyrin analogues in dye-sensitized solar cells

The regeneration reaction of sensitizers in dye-sensitized solar cells is one of the critical steps in photonic chemical circuits. In this report, the two-step regeneration reaction of a series of zinc porphyrin sensitizers with a variety of substituent groups, i.e., CN-, F-, Cl-, H-, PhCH3-, OH- and NH2- groups, has been studied using density functional theory (DFT). The effects of the substituent groups on the structures of zinc porphyrin sensitizers, the regeneration intermediates and the reaction thermodynamics and kinetics have been explored. It is found that substituent groups at meso-position of zinc porphyrins strongly influenced the mode of two-step regeneration. For Por-CN, Por-F and Por-Cl, the formation of DyeI(Zn) and DyeI(Zn)-I intermediates are dominant, whereas for Por-H, Por-PhCH3 and Por-OH, the formation of DyeI(Py) and DyeI(Py)-I intermediates predominate. Due to the stronger electron-withdrawing effect of CN- and F-, the corresponding Por-CN and Por-F have no energy barrier in reaction. This suggests that their regeneration should be faster than the others. Besides two-step regeneration, alternative regenerations including one-step regeneration and reductive quenching reaction of excited dye and the influences of substituent groups on the electron injection efficiency are also estimated. These results provide valuable information for the design of novel zinc porphyrin analogues for DSCs.

Oxychlorination of CO to phosgene in a three-step reaction cycle and corresponding catalytic mechanism

An improved procedure, three-step reaction cycle procedure, for the continuous preparation of phosgene from CO, air and HCl catalyzed by CuCl 2 was reported for the first time. The corresponding catalytic mechanism of each step was preliminarily disclosed with the powder X-ray diffraction (XRD) analysis: the first step is the oxychlorination of CO to phosgene and simultaneous reduction of CuCl 2 to CuCl; the second step is the oxidation of CuCl with air to Cu 2OCl 2, and the third step is the neutralization of Cu 2OCl 2 with HCl to CuCl 2. The regeneration of catalyst consists of steps 2 and 3, which is called the two-step regeneration of catalyst. The no-simultaneous existence of Cu (I) chloride and water in this three-step reaction procedure prevented effectively copper (I) chloride from the disproportionation. The influence of regeneration conditions, including reaction time, pressure of air or HCl on morphologies and recovery degree of catalyst were investigated and discussed. The degree of recovery for the single-run yield and cumulative yield of phosgene from the two-step regenerated oxychlorination agent can reach, respectively, 87.0% and 97.0% whereas the single-run yield and cumulative yield of phosgene with the one-step regenerated catalyst only can be recovered to 58.8% and 80.5%, respectively. The two-step regeneration method also can result in a higher dispersion of CuCl 2/KCl on silica gel than that of the one-step regeneration. These results not only can offer a quite promising potential for the industrial use, but also can promote our deeply understanding of this important industrial reaction.

Agrobacterium mediated transformation of sugarcane for borer resistance using Cry 1Aa3 gene and one-step regeneration of transgenic plants

Sugarcane borers are the major biotic pest in sugarcane that accounts nearly 25-30% yield loses. Most of the present sugarcane varieties are not resistant to borers. Development of borer resistance in sugarcane through transgenic technology could be the best approach. Cry series of genes are known for development of insect pest resistance in plants in particular for the most damaging order 'Lepidoptera'. The sugarcane (Saccharum hybrids) genotype CoC671 was transformed by Agrobacterium mediated method. Cry 1Aa3 gene driven by CaMV35S promoter and Ocs terminator with selectable marker nptII driven by Nos promoter and terminator harboring in binary vector pBinAR was transformed into Agrobacterium tumefaciens strain EHA 105 was used in sugarcane transformation. Young leaf roll discs were infected and regenerated plants were obtained in one step after infection with minimal callus phase. Three to four shoots per explant were developed after 7-10 days incubation. Regenerated shoots were allowed to grow further. Two months old putative transgenic plants were taken for molecular characterization. Out of 65 plants tested by PCR, 24 plants were positive for Cry1Aa3 gene. This represents nearly 28% of the transformation efficiency. All these plants were analyzed by Southern blot hybridization for integration of the inserted gene. Four plants showed single copy number and another two showed more than two integrations. All those 24 plants that are positive by PCR were subjected to ELISA test for expression of foreign protein. It was observed that four transgenic plants showed around ten-fold high level expression and another two plants showed with moderate levels, 3-5 fold expression.

Rhizobium radiobacter conjugation and callus-independent shoot regeneration used to introduce the cercosporin export gene cfp from Cercospora into sugar beet (Beta vulgaris L.).

Leaf spot disease caused by Cercospora is responsible for crop and profitability losses in sugar beet crops in the US and worldwide. The cfp gene that encodes a protein that exports phytotoxic cercosporins from Cercospora was conjugally transferred to sugar beet using Rhizobium radiobacter (Agrobacterium tumefaciens), to improve Cercospora-induced leafspot resistance. Conditions for shoot regeneration were optimized to increase regeneration/transformation efficiencies. Low-light and room-temperature conditions were favorable to sugar beet regeneration without callus when cytokinin had been added to the tissue culture medium. Using this procedure adventitious shoots from leaf pieces were obtained in a simple, one-step regeneration procedure. T7, a cfp-transgenic clone verified by PCR with gene-specific primers, is being propagated for leaf spot disease resistance evaluation.

Morphogenic response of the alginate-encapsulated axillary buds from in vitro shoot cultures of six mulberries

Axillary buds obtained from in vitro shoot cultures of six mulberries (Morus alba L., M. australis Poir., M. bombycis Koidz., M. cathyana Hemsl., M. latifolia Poir., and M. nigra L.) were encapsulated in calcium alginate hydrogel containing Murashige and Skoog (1962) nutrients (MS) and 4.4 μM benzyladenine (BA). Morphogenic response of encapsulated buds to various planting media such as MS medium + 4.4 μM BA, MS basal medium, soilrite mix + half-strength MS medium, garden soil + half-strength MS medium, soilrite mix + tap water and garden soil + tap water was evaluated. Encapsulated buds of M. alba, M. bombycis, M. latifolia and M. nigra exhibited shoot development in each of the six media tested whereas that of M. australis and M. cathyana responded only to the first four media. Analysis of variance revealed that the planting medium exhibited the greatest influence on shoot development. Of the six planting media evaluated, shoot development was highest in MS medium containing 4.4 μM BA and lowest in garden soil moistened with water. Of the six Morus species studied, one-step regeneration, i.e. both shoot and root formation, was recorded in M. alba, M. bombycis and M. latifolia. Rooted shoots were retrieved from encapsulated buds of these species on all planting media tested except the one that contained BA. Root development was significantly affected by the planting medium and the plant species with planting medium contributing the maximum amount (82%) of the total variation observed. Of the five planting media tested, the percentage of root development was highest in MS basal medium. Of the six Morus species studied, the best shoot and root development was observed in M. alba. Encapsulated buds of M. bombycis, M. latifolia and M. nigra stored for 90 days and those of M. alba, M. australis and M. cathyana for 60 days at 4 °C still regenerated shoots. Plants regenerated from the encapsulated buds were hardened off and transferred to soil.

Somatic Embryogenesis in Trifolium: Protein Profiles Associated with High-and Low-Frequency Regeneration

Summary A one-step regeneration system was developed for Trifolium rubens and Trifolium pratense using petiole segments of shoot cultured in vitro . Isogenic cell lines of T . rubens showing high- or low-frequency somatic embryogenesis (18 and 0.2 embryos per explant respectively) were isolated from a single seedling genotype by successive cycles of selection and subculture. Variation in the frequency of embryogenesis apparently arose by somaclonal variation in callus cultures, and in basal callus regions of shoot cultures. Using two-dimensional gel electrophoresis, the polypeptide translational profiles of cultured petioles from T. rubens isolines were examined over a 20-day interval covering the induction period for somatic embryogenesis. Two different genotypes of T. pratense , showing high frequency or zero somatic embryogenesis in the same culture system, were also included in the protein analysis. Two polypeptides exhibiting appropriate behavior for association with somatic embryogenesis were detected in the three regenerating lines. These same two components were also detected in the non-regenerating T. pratense genotype. In this latter genotype, however, they were found to exhibit a translational pattern different from that expected of proteins involved in somatic embryogenesis.