As the new energy industry advances, extracting lithium from secondary resources such as process tail liquor has become an effective approach to meet the ever-growing demand for lithium resources. In this work, a synergistic extraction system composed of 4-octyloxy-2-hydroxybenzophenone (HOOBP) and trioctyl phosphine (TOP) was used to recover lithium from alkaline high-sodium tail liquor. The key influencing factors for lithium extraction were investigated at first. The optimal organic phase composition (0.3 mol/L TOP and 0.2 mol/L TOP) and single-stage extraction conditions (COH- = 0.4 mol/L) were determined, with the lithium extraction efficiency of 79% and the Li/Na separation coefficient ~ 200. The process parameters for multistage extraction, scrubbing, and stripping were optimized, and a full-process scheme consisting of "four-stage extraction, three-stage scrubbing, and three-stage stripping" was designed. A total of 250 h of process verification was conducted on 10 stages mixer-settler unit, the lithium extraction efficiency remained stably above 98%. The lithium concentration in the resultant lithium-enriched solution reached over 25 g/L, with impurity ions below 0.1 g/L, and the purity of the prepared Li2SO4·H2O was 99.88%. At the molecular level, the complex configuration was elucidated by Fourier transform infrared spectroscopy (FT-IR) and density functional theory (DFT) calculations. This research lays a theoretical and experimental foundation for lithium recovery from complex alkaline lithium-containing resources, and provides a promising technical route for practical applications.

Amide compounds were employed as stable, environmentally friendly, and highly efficient extractants in hydrometallurgy, which exhibit considerable potential for lithium recovery from high Mg/Li ratio salt lake brines. To investigate the structure-efficiency relationship (SER) to inform the development of novel amide-based lithium extractants, 40 amide compounds were designed, synthesized, and characterized herein. The SER was determined via extraction efficiency evaluation under the optimized conditions for N,N-bis(2-ethylhexyl)acetamide (N523), and the extraction mechanism was clarified through integrated experimental and quantum calculation. The results demonstrate that most of the amide extractants synthesized in this work exhibit excellent lithium extraction efficiency and favorable Mg/Li separation performance. The maximum single-stage lithium extraction efficiency reaches as high as 93%. Molecular weight, structural rigidity, electron-withdrawing effect, and steric hindrance all act as key factors governing the SER within each series, among which the electron-withdrawing effect exerts the biggest influence. The existence of the [FeCl4]– anion in the extraction mixture generated by the representative N,N-dibenzylbenzamide (E25) was confirmed, and the first direct evidence for the integrated conjugated configuration of the amide group in the extraction complex was obtained via XPS analysis. Overall, this work delivers essential theoretical insights for designing and developing advanced amide extractants, promoting the high-efficiency utilization of lithium resources in salt lakes.

Aliphatic diols are widely recognized as high-performance extractants for boron recovery. However, their industrial implementation is severely hampered by the inherently high aqueous solubility of currently available diol-based extractants. In this work, a novel aliphatic 1,3-diol was designed and synthesized, in which the functional moieties essential for boron chelation were fully retained, while its dissolution loss into the aqueous phase was substantially mitigated by extending the alkyl chain length. The boron extraction performance of the as-synthesized extractant was systematically investigated in both synthetic boric acid solutions and raw salt lake brine, with particular emphasis on the effects of key operational variables, including extractant concentration, organic-to-aqueous phase ratio (O/A), temperature, pH, and salting-out effect, on extraction efficiency. Total organic carbon (TOC) analysis revealed that the aqueous solubility of the novel 1,3-diol was reduced by 95% relative to that of the widely used aliphatic 1,3-diol TMPD. Thermodynamic analysis based on the van’t Hoff equation demonstrated that the extraction process is exothermic (ΔH < 0), indicating that elevated temperature shifts the equilibrium unfavorably for boron extraction. This extraction system exhibits outstanding extraction performance at pH ≤ 8, enabling direct boron recovery from raw salt lake brine without any pre-acidification. Coexisting cations in brine, including Li+, Na+, K+, Ca2+, and Mg2+, all exerted a promoting effect on boron extraction. Using raw brine from the Xitaijiner Salt Lake as the feedstock, a full-process flowsheet test comprising three-stage extraction, one-stage scrubbing, and one-stage stripping was conducted, achieving both boron extraction and stripping efficiencies exceeding 98%. Ten consecutive cycling tests confirmed that the developed extractant possesses excellent cycling stability and hydrophobicity, demonstrating promising potential for industrial-scale boron recovery.

Lithium has become a strategic resource for the new energy industry, while geothermal brine represents a promising supplementary lithium source with low lithium concentration and ultrahigh sodium-to-lithium ratio. The existing extraction studies focus mainly on mechanism and performance rather than integrated process development. This work established a complete solvent extraction process using a beta-diketone-based extraction system (HBNA/TRPO) to recover lithium from Jianghan Basin geothermal brine (48 mg/L Li+) and battery-grade lithium carbonate was prepared from the lithium-enriched liquor. The process involved calcium/magnesium pre-removal, lithium extraction, sodium scrubbing, lithium stripping, and lithium carbonate precipitation. Under optimized conditions, Ca and Mg removal reached 96% and 99% with less than 5% Li loss, and lithium extraction efficiency exceeded 95% at 50% saponified organic phase and O/A = 1/2. In the stripping process, lithium could be concentrated to 4.1 g/L, and to facilitate subsequent lithium carbonate precipitation, the lithium-rich solution is further concentrated by evaporation to 12 g/L. After deep removal of calcium and magnesium, the Li2CO3 product with purity of 99.5% was prepared by adding sodium carbonate. Cycling process and techno-economic analysis shows confirmed stable extraction performance and favorable cost-price margins. This research provided a practical, scalable route for lithium extraction from low-grade, high-Na/Li geothermal brines, supporting the development of unconventional lithium resources.

The design of novel lithium extraction agents and the exploration of their structure-activity relationships are the core and key aspects in the field of lithium extraction and separation. This study reports the design and synthesis of ten novel o-hydroxyphenyl phosphonate based extractants (P1-P10) for efficient lithium extraction. Systematic evaluation revealed that introducing long/branched alkoxy chains on phosphorus or electron-withdrawing groups at 5-position of benzene ring significantly enhanced extraction performance. An optimized synergistic system comprising P8 and TRPO was developed, exhibiting high stability, continuous operability without regeneration, and streamlined processing. Employing a three-stage counter-current extraction, three-stage scrubbing, and two-stage stripping process, the P8/TRPO system achieved > 95% Li+ extraction efficiency from industrial lithium precipitation mother liquor. Remarkably, Li+ concentration was enriched from 1.22 g.L-1 to 29 g.L-1, while Na+ and K+ concentrations were reduced to 0.39 g.L-1 and 1.2 & times; 10(-3) g.L-1, respectively. Mechanistic studies (UV-Vis/IR spectroscopy) confirmed distinct electronic and conformational changes in P8 and P8/TRPO upon Li+ binding. While P8-Li+ binding enhanced pi-electron conjugation, P8/TRPO-Li+ coordination reduced the orbital gap without improving conjugation, attributed to participation of TRPO. Thermodynamic analysis (Delta H = -13.83 kJ.mol(-1), Delta G < 0, Delta S > 0) verified a spontaneous, exothermic extraction process. This work provides new strategies for designing high-performance alkali metal separation materials and establishes a feasible process for selective lithium recovery in alkaline systems, with future potential for enhanced selectivity via structural modification.

The development of highly selective and stable extraction systems poses significant challenges for lithium recovery from high Na/Li brines. The present study proposed a novel diketone system comprising 0.4 mol/L PDDK/TRPO-kerosene for Li+ extraction from typical sodium sulfate-subtype Mamicuo salt lake original brine. Implementing a simplified integrated strategy of 'calcium-magnesium chelation - organic regeneration - lithium extraction' has achieved effectively precision removing impurities such as Ca2+ and Mg2+, and extracting Li+. This study systematically examined the impact of fluorinated versus non-fluorinated extractants on the extraction of Ca2+, Mg2+ and Li+. The influence of major anions in brine on Li+ extraction was also examined. The investigation also involved optimizing the entire seven-stage process and its underlying mechanism. Findings suggested that fluorinated beta-diketone extractants demonstrate increased metal ion extraction capacity at low pH, while equimolar lithium-to-alkali ratios ensure efficient Li+ extraction. The ability of alkaline anions to promote Li+ extraction was as follows: OH- > CO32- approximate to B4O72- >> HCO3-. Li+ recovery efficiency was found to be 96%, and the Li-rich solution exhibited Li+ of 22.4 g/L, as well as Na+ of 0.75 g/L and total Ca2+ and Mg2+ of 0.008 g/L. The inherent structural advantages of PDDK simplified the separation process and ensured high stability with a solubility of 17.12 mg/L. The enol-form of CO in PDDK has been revealed to form a complex Li & centerdot;PDDK & centerdot;TRPO. This study provides novel insights and technological support conducive to environmental sustainability for the efficient extraction of Li+ from brines with a high Na/Li ratio.

The efficient extraction of lithium from magnesium-rich salt-lake brines is crucial for sustainable lithium production, yet it remains challenging due to the similar physicochemical properties of Li+ and Mg2+. While the tri-butyl-phosphate (TBP) extraction system shows high selectivity for lithium over magnesium, the molecular-level mechanism behind this selectivity remains unclear. Herein, we propose that the differential hydration energy cost, quantified through a water molecule transfer equilibrium between ion hydration clusters, is the key factor governing separation efficiency. Using a consistent density functional theory approach (wB97X-D4/def2-TZVPPD), we systematically computed the solvation structures and stabilities of water clusters, [Li(H2O)n]+ and [Mg(H2O)n]2+. Our results reveal that ion and water molecule interactions in the first hydration sphere are significantly stronger than water molecule interaction in the second hydration sphere. Most notably, equilibrium analysis indicates that under high Mg2+ conditions, the prevailing hydration states are [Li(H2O)4]+ and [Mg(H2O)10]2+. The additional hydration waters around Mg2+ substantially increase the energy penalty for its dehydration upon extraction, thereby explaining the superior selectivity of TBP for Li+. This work not only resolves a long-standing puzzle in lithium extraction but also introduces a general theoretical framework for understanding ionic hydration and selectivity in separation processes.

In ecologically fragile and geomorphologically complex mountainous regions, ensuring a smooth transition from poverty alleviation to multidimensional sustainable rural development remains a key issue in regional governance. Focusing on the Qinba Mountains, a typical former contiguous poverty-stricken region in China covering 18 prefecture-level cities in six provinces, this study uses 2009-2023 prefecture-level panel data to examine the spatiotemporal evolution and driving mechanisms of coordinated rural revitalization. An integrated framework of "multi-dimensional evaluation-spatiotemporal tracking-attribution diagnosis" is developed by combining the improved AHP-entropy-weight TOPSIS method, the Coupling Coordination Degree (CCD) model, spatial Markov chains, spatial autocorrelation, and the Geodetector. The results show pronounced subsystem asynchrony. Livelihood and Well-being Security (U5) improves steadily, while Level of Industrial Development (U1), Civic Virtues and Cultural Vibrancy (U3), and Rural Governance (U4) also rise but with clear spatial differentiation; by contrast, Quality of Human Settlements (U2) fluctuates in stages under ecological fragility. Overall, the coupling coordination level advances from the Verge of Imbalance to Intermediate Coordination, yet the regional pattern remains uneven, with eastern basin cities leading and western deep mountainous cities lagging. State transitions display both policy responsiveness and path dependence: the probability of retaining the original state ranges from 50.0% to 90.5%; low-level neighborhoods reduce the upward transition probability to 25%, whereas medium-to-high-level neighborhoods raise the upward transition probability of low-level cities from 36.36% to 53.33%. Spatial dependence is also evident, with Global Moran's I increasing, with fluctuations, from 0.331 in 2009 to 0.536 in 2023; high-value clusters extend along the Guanzhong Plain-Han River Valley corridor, while low-value clusters remain relatively locked in mountainous border areas. Driving mechanisms show clear stage-wise succession. At the single-factor level, the explanatory power of Road Network Density (F6) declines from 0.639 to 0.287, whereas Terrain Relief Amplitude (F1) becomes the dominant background constraint in the later stage (q = 0.772). Multi-factor interactions are generally enhanced. In particular, the traditional infrastructure-led pathway weakens markedly, with F1 boolean AND F6 = 0.055 in 2023, while the interaction between terrain and consumer market vitality becomes dominant, with F1 boolean AND F7 = 0.987 in 2023. On this basis, three major pathways are identified: government fiscal intervention and transportation accessibility improvement, capital agglomeration and market demand stimulation, and human-earth system adaptation and ecological value realization. These findings provide quantitative evidence for breaking spatial lock-in and improving cross-regional resource allocation in ecologically constrained mountainous regions.

With the booming development of the new energy industry, lithium has gained ever-growing strategic importance, thus upgrading the comprehensive utilization efficiency of lithium resources has become a critical issue worldwide. In this work, targeting the recovery of lithium from alkaline lithium-bearing solutions, a novel triazole-based extraction system containing 2-(2H-benzotriazo-2-yl)-6-dodecyl-4-methyl-phenol(A571) and trialkylphosphine oxide(TRPO) was developed. Key parameters governing lithium extraction performance, including organic phase formulation, aqueous phase properties, extraction contact time, and the acid-alkali stability of the A571 extraction system, were systematically evaluated. Based on the equilibrium extraction results, a comprehensive process investigation for lithium recovery from lithium hydroxide by-product feed solution was conducted, and an integrated process flowsheet comprising extraction, scrubbing, stripping, and organic phase regeneration was established. This optimized process achieved a total lithium recovery of 99 %, yielding a high-grade lithium-rich solution with a lithium concentration of up to 20 g/L. Compared with conventional solvent extraction systems, the triazole-based extractant developed in this work enables efficient lithium extraction under strongly alkaline conditions, and no appreciable dissolution loss of the organic phase was observed. This study provides a novel and promising strategy for the efficient recovery of lithium resources, with great potential for industrial scale-up.

In this study, tri-(2-ethylhexyl) phosphate (TOP) was employed as extractant and FeCl3 as co-extractant to extract Li from high Mg/Li ratio brine. The effects of TOP concentration, Fe/Li molar ratio, acidity of brine, phase ratio and co-existing cations were discussed and achieved high Li extraction efficiency of 90.62% and superior Li/Mg separation coefficient of 1331 in single stage. TOP-FeCl3 system exhibited outstanding selectivity between Li and co-existing cations, and the extraction sequence was determined as: Li+ > Na+ > Ca+ > K+ > Mg2+. The operational details of the multi-stage countercurrent extraction, stripping, and the regeneration of organic phase regeneration processes were systematically optimized. The Li extraction capability in organic phase could be precise controlled through systematic modulation of the concentration of TOP, the Fe3+ loading amount in organic phase and the saponification degree. A full-flow extraction process was proposed and verified through 21 consecutive extraction cycles, resulting in an average Li extraction efficiency of 95.95%. The concentrations of Li, Mg, Na and Fe in the obtained stripping solution were 36.74 g/L, 0.6169 g/L, 0.5719 g/L and 0.0549 g/L, respectively. The Mg/Li mass ratio was reduced from 49.3 in the salt lake brine to 0.0168 in the stripping solution and the purification factor was up to 2900. A comprehensive pilot-scale process flowchart was suggested. This study holds significant importance in advancing the industrial application of TOP-FeCl3 system for lithium recovery from high Mg/Li ratio brines.

With the rapid development of the new energy industry in recent years, the importance of lithium has become increasingly prominent; therefore, improving the comprehensive utilization efficiency of lithium resources is particularly crucial. This study focuses on the recovery of lithium from the lithium precipitation mother liquor of lithium carbonate and has developed a solvent extraction system based on salicylate esters. Compared with traditional solvent extraction systems, the extraction system proposed in this work exhibits advantages such as high capacity and fast phase separation. Using the lithium precipitation mother liquor as the raw material, under the condition of phase ratio O/A = 1/5, the lithium extraction rate can reach more than 95% through 2-stage countercurrent extraction, and the lithium loading capacity in the organic phase can reach 7.5 g/L. After 2-stage scrubbing and 1-stage stripping, a lithium-rich solution with a concentration of 35 g/L can be obtained, which greatly simplifies the lithium recovery process. Furthermore, the system designed in this study demonstrates excellent stability during the extraction-stripping cycle, with no occurrence of third-phase formation or solid precipitation. The mechanism of lithium‑sodium separation by the system was investigated using ESI-MS, FT-IR, and DFT. The results indicate that both lithium and sodium form 1:1:1 complexes with the ligand in the organic phase; however, there is a significant difference in the complexation energy during the formation of complexes between lithium‑sodium and the ligands, thereby enabling the extraction separation of the two. This work proposes a new and feasible approach for the efficient recovery of lithium.

Neutral organic phosphate/FeCl3 systems are widely employed for lithium extraction from high Mg/Li ratio brines; however, extractant degradation under prolonged operational conditions constrains process sustainability. This study investigates the degradation behavior of tributyl phosphate (TBP) and trioctyl phosphate (TOP) during lithium extraction, examining the influence of key process parameters (HCl/NaOH concentration, temperature, and FeCl3 concentration) and evaluating the impact of degradation products on extraction performance. Single-factor experiments demonstrated that TOP exhibited superior stability compared to TBP, attributable to its longer carbon chains and greater steric hindrance. Both extractants displayed poorer acid resistance, whereas elevated FeCl3 concentrations significantly suppressed degradation. On the basis of these findings, optimal process conditions are recommended: minimal HCl usage, NaOH concentration ≤ 4.0 mol·L−1, and temperature ≤ 35 °C. Qualitative and quantitative 31P NMR analyses confirmed that the primary degradation product of TBP was dibutyl phosphate (DBP), while that of TOP was di-(2-ethylhexyl) phosphoric acid (D2EHPA). Subsequent single-stage extraction experiments revealed that both DBP and D2EHPA diminished lithium extraction efficiency and Li/Mg separation factors, with D2EHPA exerting a more pronounced adverse effect. Across the concentration range of 0–0.5 mol·L−1, D2EHPA reduced lithium extraction efficiency by 20%, compared to an 11% decrease caused by DBP. This study addresses a critical gap in understanding how extractant degradation affects long-term lithium extraction performance, and supplies feasible operational limits and formulation references for the industrial design and steady running of lithium separation processes.

Adsorption is a popular method for the recovery of low-grade lithium. It is a low-cost and highly efficient way to treat solutions with low lithium concentrations. The impurity content determines the industrial application. This study investigated a novel strategy to remove divalent cations from a desorption solution containing Mg2+, Ca2+, and Mn2+, generated by a manganese absorbent using an organophosphoric acid, followed by precipitation of lithium carbonate from the concentrated raffinate by evaporation. Di(2-ethylhexyl)phosphoric acid (P204) was selected as the preferred extractant. The saponification method and degree of saponification were determined, and the extraction parameters (pH, extractant concentration, and phase ratio) were investigated. A three-stage countercurrent extraction process was tested. Removal efficiencies of Mg2+, Ca2+, and Mn2+ from the manganese-containing desorption solution exceeded 99%, leaving <1.0 mg/L divalent cations in the raffinate. The raffinate was evaporated and concentrated to >23 g/L lithium. The total concentration of divalent cations in the lithium-rich solution was approximately 10.0 mg/L. Further conversion with sodium carbonate was carried out to prepare a battery-grade lithium carbonate product with a purity of 99.83%. The present work may provide a novel means of lithium recovery from a manganese-containing desorption solution.

The preparation of high-performance epoxy resins (EP) with enhanced mechanical properties and flame retardancy for building materials has long been a significant challenge. In this study, bio-based phytic acid (PA) was intercalated into the layers of layered double hydroxides (LDH) via coprecipitation. Subsequently, ultrafine Fe(OH)3 was in situ grown on PA-intercalated LDH through tannin-mediated assembly, resulting in the synthesis of the LDH-PA@TA-Fe(OH)3 hierarchical hybrid flame retardant. Comprehensive characterization of its microstructure, morphology, and chemical composition was performed. The EP composite demonstrated a LOI of 31.3 % and a UL-94 V-1 rating when the additive of 7.5 wt% LDH-PA@TA-Fe(OH)3 was utilized. Additionally, the EP/LDH-PA@TA-Fe(OH)3 composite demonstrated a substantial reduction in peak heat release rate (pHRR) and peak smoke production rate (pSPR) with reductions of 48.1 % and 52.7 %, respectively, along with a 62.5 % decrease in peak CO production rate (pCOP), compared to neat EP. These improvements in fire safety are primarily ascribed to the synergistic flame retardancy of LDH and Fe(OH)3 in condensed and gas phases, along with the efficient catalytic charring performance of PA and Fe3+. Furthermore, the incorporation of LDH-PA@TA-Fe (OH)3 enhanced the mechanical properties of EP, which could be ascribed to the improved dispersibility of the modified LDH and the strengthened interfacial interaction. This study introduces a novel approach for the development of highly effective LDH-based hybrid flame retardant materials, enabling the fabrication of EP composites with superior mechanical performance and fire safety.

Layered double hydroxides (LDHs) are increasingly being used in polymer flame retardancy, but current developments often overlook the effects of various structural factors on flame suppression effectiveness. These factors are crucial for the design of high-performance flame retardants. To investigate the structure-function relationship between anion species and polymer flame retardancy, Mg-Al LDHs of BAL, BPL and BSL, intercalated with anions of benzoic acid (BA), benzene hypophosphorous acid (BP) and benzene sulfinic acid (BS), respectively, were synthesised via co-precipitation. Their properties, including flame retardancy, were systemically investigated in this study. Despite their similar structures, with only differing acid species, BAL, BPL and BSL exhibited similar interlayer distances but varied in their intercalation capability, crystallisation, thermal decomposition and surface hydrophobicity. Compared to pure EP, the composites containing LDHs, particularly BSL, performed significantly better in limiting oxygen index, vertical burning and cone calorimeter tests. The improvement can be attributed to the carbonisation and altered decomposition pathways of the composites. All three LDHs seemed to have little impact on the tensile strength and dielectric properties of the composites. The results of this investigation indicate that the acid species can significantly affect both the properties of the LDHs and the composites. Furthermore, sulfinic acid, or the sulfur element in LDHs, may exhibit superior performance in polymer flame retardancy. This provides valuable insight into the structure-function relationship study of LDH-based flame retardants and lays a solid foundation for the design of novel, high-efficiency LDH flame retardants.

This paper presents a novel system and method for the extraction and separation of boron from alkaline solutions. The extraction system consists of a 1:1 molar ratio of 2-octanol and salicylate ester, which effectively extracts boron from the solution. The extraction efficiency of boron increases with the pH of the solution, reaching up to 75 % in a single extraction stage when pH > 9. The study also investigates the effects of extraction ratio, extraction time, and extraction temperature on the extraction performance. Under optimized conditions, using natural salt lake brine from Tibet as the raw material, a three-stage countercurrent extraction process can achieve a boron extraction rate of 95 %. After subsequent stripping and concentration, boric acid can be directly produced with a purity exceeding 99 %. Moreover, the extraction system demonstrates good stability during the extraction-stripping cycle. FT-IR and Raman spectrum were employed to investigate the main functional group of the extraction process, and DFT was used to study the coordination mechanism. This work provides an effective pathway for the comprehensive utilization of boron in alkaline solutions.

The synergistic enhancement of pollution and carbon reductions serves as a primary lever for promoting the comprehensive green transformation of economic and social development,with energy being a crucial battleground for this green transition.In this study,we conduct an in-depth exploration of the strategic implications of green and low-carbon energy transition and pollution and carbon reductions.We construct an evaluation index system for green and low-carbon energy transition and pollution and carbon reductions.We employ a combination of the entropy weight method,Kernel density estimation,composite system synergy model,Theil index,and spatial Markov chain methods to empirically analyze the regional disparities and dynamic evolutionary characteristics of the synergistic effects of green and low-carbon energy transition and pollution and carbon reductions in the Yangtze River Economic Belt from 2010 to 2022.The results indicated that:① Both the green and low-carbon energy transition index and the pollution and carbon reduction index have shown a steady growth trend,with the gap in green and low-carbon energy transition levels among provinces gradually widening,while the gap in pollution and carbon reduction levels first narrowed and then widened.② The level of synergistic development between the green and low-carbon energy transition and pollution and carbon reductions significantly increased,with the overall coordination level demonstrating a dynamic process from mild incoordination to mild coordination and then to moderate coordination and a spatial distribution situation of"high on both sides,low in the middle"gradually emerging regionally.③ The overall disparity in synergistic levels first rose and then fell,with the contribution rate showing that before 2017,it was mainly due to differences within regions,and after 2018 it was mainly due to differences between regions.The overall difference values by region were as follows:midstream areas>upstream areas>downstream areas.④ The probability of upward transition was highest for low synergy levels,followed by moderate synergy levels;considering the impact of spatial neighborhood factors,neighborhoods with low synergy levels could hinder the development of local synergy types to some extent,while neighborhoods with higher synergy levels could have a pulling effect on the local area.Finally,some suggestions are put forward,such as increasing the policy inclination and technical support for areas with a low level of synergy and strengthening the radiation demonstration role of areas with high level of synergy.

BackgroundRed raspberry (Rubus idaeus L.) is a renowned fruit plant with significant medicinal value. Its nuclear genome and chloroplast genome (plastome) have been reported, while there is a lack of genetic information on its mitogenome. We sequenced and assembled the complete mitogenome of R. idaeus, and conducted a series of genetic investigations comparing it with the nuclear and chloroplast genomes, so as to better gain a comprehensive understanding of the species' genetic background.ResultsThe mitogenome is represented by one circular chromosome of 438,947 bp. Twenty-four core genes, nine variable genes, 26 tRNAs, and three rRNAs were annotated. A total of 52 SSRs and 38 tandem repeat sequences were identified. 533 pairs of dispersed repeats were detected, among which three pairs were found to have mediated the homologous recombination, resulting in one major conformation and seven minor conformations. Furthermore, 52 homologous sequences between the mitogenome and plastome were identified, including six complete protein-coding genes and 12 tRNA genes. We also detected 828 homologous fragments between the nuclear genome and mitogenome, including one trnM-CAU gene.ConclusionsIn this study, we presented the mitogenome of R. idaeus for the first time based on data obtained from Illumina and Oxford Nanopore sequencing platforms. Key characteristics of the mitogenome were examined, including its gene composition, repetitive elements, and homologous DNA fragments. Additionally, we identified multiple recombination events in the mitogenome mediated by repetitive sequences The high-quality and well-annotated mitogenome for the known fruit red raspberry will provide essential genetic information for species classification, evolution analysis, and even genetic improvement in Rubus in the future.