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Abstract High-strength bolts have become indispensable support materials in geotechnical engineering, but the incidence of safety accidents caused by bolt fractures under complex geological conditions is increasing. To address this challenge, this study focuses on a typical roadway in the Xinjulong coal mine, employing a combination of mechanical performance testing, microscopic and macroscopic analyses to investigate the failure mechanism of bolt breakage. The research indicates that the cracks in the failed bolts underground exhibit subcritical patterns, with the presence of oxides and Cl elements, and multiple intergranular fractures internally, consistent with the characteristics of stress corrosion failure. Additionally, inherent defects in the bolts are also a primary cause of failure. For instance, for type A bolts, the levels of P and S elements significantly exceed the normative requirements, forming inclusions, while the low content of elements like Si and V leads to reduced plasticity, toughness, and corrosion resistance. Furthermore, the excessive pitch in type A bolts leads to stress concentration and cracking under complex loads. The study concludes that the synergistic effect of stress corrosion cracking and inherent flaws in bolts are the main causes of failure. Therefore, it is recommended to enhance the reliability and safety of bolt support by optimizing the bolt shape and developing anti-corrosion bolts, thereby achieving long-term stability in underground engineering.

The combination of nanocolloidal silica and aluminate cement is a potential technical approach to solve the problem of mudstone grouting, but there is a lack of high-performance admixtures to improve early strength and gel time. The effects of three common organic acids, citric acid, tartaric acid and malic acid, on the properties of the composite slurry were explored. Meanwhile, the influence of citric acid on the fluidity and microstructure characteristics of the composite slurry was deeply analysed. Finally, the key engineering properties such as injectability and reinforcement of composite slurry were explored. The main conclusions were as follows: the citric acids had a significant beneficial effect on the compressive strength and gel time. After the addition of 4% citric acid, the consolidation rate of the composite slurry was 92.68%, the compressive strength was 39.22 MPa, the consolidation rate and compressive strength were at high levels, and the gel time was 90–110 min. The main reasons for the excellent strength performance were the dense microstructure, CAH10 and C2AH8 hydrates and 98.68% of pores having pore sizes less than 20 nm. The composite slurry can be injected in the rock with average pore throat diameter of 15.14 μm. The hydration products could be better combined with mudstone, the rock softening zone was smaller than that of ordinary Portland cement, and the composite slurry could reduce the softening phenomenon of mudstone. The findings of this work could provide guidelines for the development of high-performance grouting materials and solving the reinforcement problem of mudstone.

High-frequency, low-energy impacts consistently inflict damage on the surrounding rock and anchoring structure in deep roadways, leading to ongoing instability. The construction of anchoring support system that can withstand these dynamic impact loads is identified as crucial in deep coal mining. Through theoretical analysis, laboratory experiments, and numerical simulations, the stress transfer and transformation mechanisms within the anchoring structure under such loads are explored. The cumulative damage and progressive failure of the structure are studied, with criteria being proposed for controlling the roadways under dynamic impact conditions. The findings reveal that three primary elements, i.e., compressive stress, tensile stress, and oscillatory effects caused by quick transitions between compression and tension, are responsible for damaging the anchoring structure. Crucially, the failure of anchoring interface under such conditions is primarily due to the medium's compressive strength and uncoordinated deformation. Damage in the anchoring structure accumulates under internal normal forces, leading to failure when the tangential modulus turns negative or the deformation from a single dynamic impact continuously increases contrary to expectations. A significant cumulative-mutation effect is observed under the combined influence of compression, tension, and oscillation, particularly in terms of the loss of pre-tightening force and internal damage in anchoring structure. Internal fissures predominantly exhibit tensile fractures, with an overall deterioration transitioning gradually from oscillatory effects to tensile stress effects, and subsequently to compressive failure effects. To effectively reduce this cumulative damage, it is crucial to improve the coordinated deformation capacity of both the surrounding rock and the anchoring agent. Additionally, increasing the anchoring length not only enhances structural stiffness but also mobilizes a broader range of rock mass for load-bearing, thereby protecting the anchoring interface, ensuring that the shear resistance in the anchoring structure’s bearing area surpasses the internal normal driving force during dynamic impacts, and mitigating the effects of oscillation can effectively reduce the cumulative damage degree of the anchoring structure. Finally, a new guideline for controlling the roadways under dynamic impact loading is proposed. The guideline, characterized by low energy, high resistance, and an allowance for compression, includes strategies such as far-field unloading, strong support in the near field, modification of fractured surrounding rock, maintaining pre-tightening force, and incorporating compression structures. It aims to provide an effective guidance for the maintenance and control of roadways in similar conditions.

Abstract With the development of deep mining of coal resources, the problem of deep roadway management is becoming increasingly prominent. This study aims to analyze the deformation and failure mechanism of deep-buried soft rock roadway under the influence of mining. Taking the material roadway of 3205 working face in Xin’an Coal Mine as the engineering background, this study analyzed the characteristics of roadway deformation and failure and its influencing factors through field investigation. This study firstly expounded the principles of graded continuous anchorage for roadway roof and then proposed a new support scheme whose feasibility was verified by numerical simulation. Field verification shows that the optimized support scheme can effectively control the deformation of roadway surrounding rock. Specifically, the deformation of roof and two sides is reduced by 91% and 50% respectively; the maximum crack depth decreases from 9.56 to 3.26 m, indicating that the roof crack development has been significantly inhibited. The new support scheme builds a solid anchored rock beam structure with thick roof layer, which can maintain the long-term stable bearing capacity of deep-buried composite roof roadway. This study provides a solution for the surrounding rock control of deep soft rock roadway.

Micro-pore grouting consolidation constitutes a pivotal technical solution for addressing the issue of water-related weakening in mudstone. Given the engineering challenges such as the sub-optimal injectability of cement slurry materials into mudstone, and the deficient reinforcement strength of silica sol in the same, this study provisionally developed a composite grouting material with a multi-particle size distribution, which is suited for the closure and reinforcement of microcracks in mudstone. We characterized the fundamental solidification and grouting properties of the modified composite grouting material, and unveiled the reinforcement mechanism of aluminate cement (AC) modified silica sol. The research findings indicate that the composite grouting material exhibits a two-tiered advantageous particle size distribution at the nanometer and micrometer levels, resulting in a marked enhancement in injectability. When the quantity of AC is 50% of the silica sol mass, and the water-cement ratio of cement slurry is 0.6, the solidification time of the composite grouting material can be adjusted between 21 and 114.5 mins. The initial viscosity is less than 5 mPa·s, and the stone rate exceeds 97%. The 28-day cemented structure exhibits a volume shrinkage rate of merely 0.57%, and the compressive strength can attain 14.5 MPa. In terms of the modification mechanism, SiO2 nanoparticles effectively expedite the hydration process of AC within the composite grouting material, engendering chemical bonds in the hydration products. These fill the pre-existing pores of the cement cemented structure, thereby enhancing the mechanical strength and compactness of the internal structure of the composite grouting material cemented structure.

Abstract Backgroud With the reform of medical system in China, Beijing municipal hospitals explored a new pharmaceutical care model and set up medication therapy management services (MTMs) in ambulatory care since 2019. We were one of the first hospitals to set up this service in China. At the present, there were relatively few reports about the effect of MTMs in China. In this study, we summarized the implementation of MTMs in our hospital, explore the feasibility of pharmacist-led MTMs in ambulatory care and the impact of MTMs on patients’ medical costs. Methods A retrospective study was conducted in a university-affiliated, tertiary comprehensive hospital in Beijing, China. The patients who received at least one MTMs and with complete medical records and pharmaceutical documents from May 2019 to February 2020 were included. Pharmacists provided pharmaceutical care for patients according to the MTMs standards issued by the American Pharmacists Association, identified the numbers and classification of the patients’ perceived medication-related demands, identified medication-related problems (MRPs), and developed the medication-related action plans (MAPs). All MRPs found by pharmacists, pharmaceutical interventions, and resolving recommendations were documented, and calculate the cost of treatment drugs that patients can reduce. Results A total of 112 patients received MTMs in ambulatory care, among them 81 cases with the completed record were included in this study. 67.9% of patients had five or more diseases, 83% of them co-took over 5 drugs. While performing MTMs, 128 patients’ perceived medication-related demands were recorded in all, monitoring and judgment of adverse drug reaction (ADR) (17.19%) was the most common demand. 181 MRPs were found, with an average of 2.55 MPRs per patient. Nonadherence (38%), excessive drug treatment (20%), and adverse drug events (17.12%) were the top three MRPs. Pharmaceutical care (29.77%), adjustment of drug treatment plan (29.10%) and referral to the clinical department (23.41%) were the top three MAPs. Whereby the MTMs provided by pharmacists, the cost-saving of each patient was about $ 43.2 monthly. Conclusion By participating in the MTMs of outpatients, the pharmacists could identify more MRPs and develop personalized MAPs timely for patients, thereby promoting rational drug use and reducing medical expenses.

Abstract Since the western region of China, which is typical of extraordinary resource endowments, has gradually emerged as the major mining zone in China, the mining of thick coal seams and roadways with coal-rock composite roof have become more and more common in this region. However, it is extremely difficult to realize safe and effective maintenance and control of such roadways due to the differences in natural endowments of coal-rock masses. With the roadway with coal-rock composite roof of Hulusu Coal Mine in western China as the engineering background, experiment research on large-scale similarity model was conducted through comprehensive measures such as the pneumatic loading system, the surrounding rock stress monitoring system, the roadway deformation monitoring system, the bolt load monitoring system, and the displacement field monitoring system in this paper. According to the results of the experiment, the control effects of the three support systems on the roadway with coal-rock composite roof were significantly different. When the single support of short anchor bolts was applied, the comparatively low initial anchor-hold failed to constrain the initial micro deformation of the roof. Consequently, wide-range fractures of the roof were triggered at a loading pressure of 0.8 MPa. In the meanwhile, the deep surrounding rocks witnessed a downward inflection point in stress, accompanied by the possibility of the collapse of the thin-layer anchorage zone at any time. As for the support combining both short anchor bolts and long anchor cables, though a reinforced effect on the bolt anchorage zone could be achieved with the help of the cables, the active reinforcement capacity of the bolt was limited. The bolt anchorage zone was the first to be damaged at a loading pressure of 0.9 MPa, which would subsequently affect the effective bearing capacity of the deep surrounding rocks. In the application of the single support of high-strength long anchor bolts, the long bolts with high pre-tightening force were able to lock multiple groups of coal-rock strata to form a thick-layer anchorage bearing structure capable of withstanding a load as high as 1.0 MPa. The crash and collapse of the coal wall eventually caused the subsidence of the roof. Based on the intense dynamic load experiment and the feedbacks of engineering application outcomes in the field, it was concluded that the high-pretension thick-layer (HPTL) anchoring technology can effectively constrain the deformation of roadways with coal-rock composite roof with favorable application outcomes.

This paper proposes a digital image processing-based detection algorithm for cross joint traces of coal roadway heading face. Initially, the acquired images were preprocessed, i.e., adaptive correction was conducted for non-uniform illumination images based on the 2D gamma function. The edge detection algorithm was then applied to extract the edges of the structural plane, followed by the filtration of the non-structural plane noises. Moreover, the Hough transform algorithm was applied to extract the linear edges; finally, the edges were locally connected in accordance with the angle and distance criteria. The experimental results show that this algorithm can be used to reduce the noise caused by non-uniform illumination and avoid the mutual interference of multi-scale edges, so as to effectively extract the traces of the cross joint. Furthermore, Q-system and rock mass rating (RMR), were applied to conduct a quantitative evaluation on the stand-up time of unsupported roof in the four test images. The Q-system quality scores are 26.7, 43.3, 3.1, and 6.7, and the RMR quality scores are 56.84, 58.73, 48.42, and 51.42, respectively. The stand-up time of unsupported roofs with a span of 4.6 m are 30, 36, 7.7 and 14 d, respectively.

It’s a universal engineering problem to seal micro-cracks of low-permeability argillaceous rock mass by grouting in the fields of civil engineering and mining. This paper achieved the grouting sealing of low- permeability artificial rocks with the permeability of 0.1–40 mD by adopting silica sol imbibition grouting. The variation characteristics of particle size, viscosity, and contact angle of silica sol during solidification and the pore size distribution of low-permeability artificial rocks were measured, and spontaneous imbibition tests of the artificial rocks were carried out. Finally, combined with the imbibition theory, percolation theory, and fracture medium grouting principle, the silica sol imbibition mechanism of low-permeability rocks and soil was discussed. The results show that: (1) Silica sol can be injected into artificial rocks with the minimum permeability of 0.1 mD through spontaneous imbibition; (2) The particle size increase of silica sol leads to decreased wettability, affinity, and injectability in grouting materials; and (3) In the range of 0.1–40 mD, the grout absorption first increases and then decreases with increased permeability. The number of large pores and fractures in the rock mass is related to injectability, and the number of small and medium pores is related to the internal driving force of imbibition. This study provides a theoretical basis for silica sol grouting sealing of low-permeability argillaceous rocks and is, therefore, an important reference for application.

The surrounding rock structure of the crossing-seam roadway is poor and is susceptible to anchorage failure phenomena, such as top plate sinking and convergence deformation under high ground stress. These issues can cause significant deformation of the surrounding rock over time, resulting in challenging engineering problems. To address this issue, we studied the failure modes and destabilization mechanisms of the surrounding rock in different crossing-seam roadways by field tests and numerical simulations. The results show that since the rock strata in these roadways are extremely unstable and highly susceptible to high horizontal stress, the weak surrounding rock presents the mode of full-section plastic failure. The roof is damaged more seriously than the floor and both walls. In this case, the basic anchorage layer in the original scheme is not thick and rigid enough to support these roadways. Thus, the surrounding rock deforms severely and persistently, which is one of the engineering failure characteristics. To solve this problem, a new scheme of “prompt thick-layer end anchorage + full-length lag grouting anchorage + secondary continuous reinforcement” was proposed based on the continuous roof control theory. According to the industrial test, this scheme can successfully control the long-term large deformation of the weak surrounding rock in crossing-seam roadways. Notably, the deformation of the top plate decreased by 56.65% and the deformation of the two walls decreased by 66.35%. Its design concept will provide important references for controlling the surrounding rock in similar soft rock roadways.

Roadways in thick coal seams are widely distributed in China. However, due to the relatively developed cracks and brittleness of coal, the support failure of thick-coal-seam roadways frequently occurs. Therefore, the study of bolt failure characteristics and new anchoring technology is very important for the safety control of thick-coal-seam roadways. Based on field observations, the failure mechanism of selected roadway failures under distinct conditions at three representative coal mines in eastern and western China was analyzed. Recommendations are provided for roadway safety control. The results show that the strength and dimension of the anchoring structure in the coal roof of thick-coal-seam roadways are the decisive factors for the resistance of the roadway convergence and stress disturbance. The thick anchoring structure in the roof constructed by flexible long bolts can effectively solve the problem of support failure caused by insufficient support length of traditional rebar bolts under the condition of extra-thick coal roof and thick coal roof with weak interlayers. The concepts and techniques presented in the paper provide a reference for the design of roadway support under similar geological conditions and dynamic load.

The higher strength of a hard roof leads to higher coal pressure during coal mining, especially under extra-thick coal seam conditions. This study addresses the hard roof control problem for extra-thick coal seams using the air return roadway 4106 (AR 4106) of the Wenjiapo Coal Mine as a case study. A new surrounding rock control strategy is proposed, which mainly includes 44 m deep-hole pre-splitting blasting for stress releasing and flexible 4-m-long bolt for roof supporting. Based on the new support scheme, field tests were performed. The results show that roadway support failure in traditional scenarios is caused by insufficient bolt length and extensive rotary subsidence of the long cantilever beam of the hard roof. In the new proposed scheme, flexible 4-m-long bolts are shown to effectively restrain the initial expansion deformation of the top coal. The deflection of the rock beam anchored by the roof foundation are improved. Deep-hole pre-splitting blasting effectively reduces the cantilever distance of the “block B” of the voussoir beam structure. The stress environment of the roadway surrounding rock is optimized and anchorage structure damage is inhibited. The results provide insights regarding the safe control of roadway roofs under extra-thick coal seam conditions.

To study the damage and destruction behavior of small coal pillars in coal mine roadway driving along gobs under long-term in-situ stress and multiple engineering disturbances, an unconfined compression experiment under a discontinuous cyclic load was designed, with the holding time as a variable. An electro-hydraulic servo rock testing machine was used to impose a discontinuous cyclic load on the coal sample and perform a final uniaxial compressive strength test. The changes in pore number and diameter in the coal under stress were monitored by nuclear magnetic resonance analysis. An increase in holding time in the discontinuous cyclic loading resulted in a significant increase in the number and diameter of pores in the coal sample; the coal porosity continued to increase, and the proportion of pores in the coal changed. The proportion of micropores decreased gradually, whereas the proportion of mesopores and macropores (cracks) increased. The degree of internal specimen damage increased with an increase of holding time, which resulted in a gradual decrease in final uniaxial compressive strength. Therefore, under the action of a long-term stress, to improve the bearing capacity of the coal pillar while avoiding gas and water influx into the working face in the goaf, the coal pillar should be reinforced with multi-layer and multi-grain grouting.

As mining depth extends continuously, complex geological environment and strong mining stress pose serious challenges against excavation safety and higher demand for bolt support. To meet the challenges, a new type of flexible bolt is developed that is free from the limitation of excavation height and can be installed quickly. The flexible bolts have a tail structure which is squeezed together by the locking casing and the steel-strand rod. The tail structure forms the thread through the rolling process, and then can be quickly installed by the nut rotation type, which avoids the disadvantages of the cable tension installation. Through the flexible long bolts, the thick anchoring layer of the roof can be constructed, and the safety control of the roadway is realized. To obtain the optimal specifications, locking casings of three diameters and lengths were used to prepare bolt samples for static tensile test. Test results show that when the diameter of locking casing is fixed, the peak resistance increases as the length of locking casing increases, but the increased amplitude tends to reduce gradually. When the length of locking casing is fixed, too large a diameter makes the mechanical property unstable. Finally, the optimal length and diameter of locking casing are set at 120 and 30 mm, respectively. In addition, cyclic loading tests were conducted, the results of which indicate that cyclic loading does not change the stress state within the bolts and that flexible bolts display a stable mechanical property. Field results indicate that flexible bolts achieve low damage of the surrounding rock and control the maximum roof fracture depth within 2.1 m, thus guaranteeing the roadway safety.

With the characteristics of gradual instability in the supporting pressure area of roadway as the engineering background, this paper aims to explore the evolution law of pore and fracture in the coal sample under progressive loads. The low-field nuclear magnetic resonance (NMR) test was designed and conducted with the coal sample under different axial loads (0, 3, 5, 7, 9, and 11 MPa). The characteristic parameters such as the porosity, the pore size distribution, the transverse relaxation time (T2) distribution curve, and the magnetic resonance image (MRI) were obtained. As the test results show, significant difference in the NMR characteristics of the coal samples can be observed throughout the compaction stage and the elastic stage. In the compaction stage, the porosity of the coal samples decreases slightly; the T2 distribution curve moves to the smaller value as a whole, and the percolation pore (PP) displays a tendency to transform to the adsorption pore (AP). In the elastic stage, the porosity of the coal samples rises gradually as the load increases; the T2 distribution curve moves to the larger value as a whole, and the AP tends to transform to the PP. The MRI shows that some pores and fissures in the coal sample close up and disappear as the load increases gradually, while the main pores and fissures expand and perforate till the macro failure occurs. Compared with one-time loading, the progressive multiple loads can ensure the fracture of the coal sample to develop more fully and the damage degree higher. It indirectly reflects that the instability and failure of the coal under the progressive load has the stage characteristics, verifying that the coal in the supporting pressure area needs to be controlled in advance.

With the increase of mining depth and strength, the evolution of bolt axial force is increasingly becoming important for ensuring the reliability and safety of support. To improve the problem of the existing coal mine roadway pressure-monitoring method, whereby it is difficult to continuously monitor the axial force of the bolt over a long period of time, a full rod fiber bragg grating (FBG) force-measuring bolt and system were designed based on the principle of fiber grating sensing. It was found that a trapezoidal groove is a relatively better groove. The linearity between the center wavelength offset of the fiber grating and the axial force was more than 0.99, and the conversion formula between the axial force of the bolt rod and the wavelength change of the fiber grating were obtained. The real-time monitoring revealed that the axial force of the bolt obviously changed before and after compression. The axial force distribution curve can be divided into the stable zone, growth zone, and peak zone. The influence of the roadway abutment pressure was approximately 130 m ahead of the working face, and the peak area was within the 25–35 m range of the advance working face. The axial force of the bolt rod at the end of the anchorage linearly increased with the tail end of the bolt, the axial force of the free segment was the largest, and the overall stress was essentially the same. The application results demonstrate the feasibility and effectiveness of the FBG full-length force bolt.

The influence of a polypropylene fiber on the tensile properties of a cement-polymer based thin spray-on liner (TSL) was investigated in this study. Two different contents of fiber were added to the liner, yielding two TSL groups. Tensile tests were performed (in accordance with the ASTM D638 standard) on the two groups of specimens as well as the control group at 1, 7, 14, and 28-day curing. The test result verified the large plasticity and low elastic modulus of the TSL compared with the fiber. SEM examination revealed that fibers lying parallel to the load direction ruptured or were pulled out from the matrix, which was beneficial to the tensile strength, but detrimental to the elongation because of their high stiffness. Other fibers lying perpendicular with the load direction were detrimental to both tensile strength and elongation through aggravating the propagation of the cracks. The tensile strength was improved by fiber incorporation, while the elongation was reduced at all curing. The influence of fibers on tensile toughness was uncertain since tensile toughness depended on strength as well as deformity.

The stability of a deep composite roof is a powerful guarantee for the safe and efficient production of a coal mine. The coal–rock combination, the single rock or coal bodies have different bearing capacity; thus, we can accurately obtain the deformation field evolution and failure mechanisms of the combination, which is useful in the deformation control of a composite roof. In this study, based on the digital speckle correlation method (DSCM), a uniaxial compression test was applied to coal–rock combinations with different height ratios. The results revealed that the compressive strength, elastic modulus, and secant modulus of the combination gradually decreased, while the decreasing amplitude weakened with the increase of coal height. Additionally, the strain field map of the combination had different characteristics in different stages. As the height of the coal body continuously increased, the gradient of the strain cloud and the area of local strain increase moved upwards. Moreover, the cracks caused by the failure of the coal body in the combination triggered the failure of the rock body. According to the test results, two principles are proposed for the deformation control of the composite roof, and are expected to be useful in applications for the similar geological conditions.

Coal-measure mudstone is a typical dual-porosity media, and grouting in a matrix system is dominantly controlled by the imbibition effect for silica sol. This paper studies the imbibition effect using mudstone in the Huaibei mining area and silica sol as grouting material as an example. Groutability, driving force, and diffusion difficulty affecting the imbibition effect were tested by a mercury porosimeter, nanoparticle size analyzer, optical contact-angle measuring device, surface tension meter, and rotary viscosity meter. After finely grinding a mudstone sample, a pressureless imbibition process was conducted through nuclear magnetic resonance equipment for 216 h to study colloid spontaneous migration and phase characteristics. Results show that silica sol absorption rate follows a power function and that the spectrograms of T2 are distributed in a triple peak pattern, with a tendency to move to the right of vertex time. The paper lays a theoretical and experimental foundation for field grouting in the coal mine.

The conversion of the highly selective CO2 reduction reaction (CO2RR) into desired value-added multicarbon compounds, like C2H4, is crucial, but it is mainly constrained by the high energy barrier for C-C coupling and the multi-electron transfer process. Herein, M/TiO2 and M/TiO2-VO (M = Cu, Pd, CuPd, and VO refers to the surface oxygen vacancy) catalysts were designed to study the CO2RR towards C2H4 by using density functional theory (DFT). We found that the surface oxygen vacancy enhances the adsorption ability of studied catalysts. The CO2 molecule is strongly adsorbed at the metal-surface interfaces of Cu/TiO2-VO, Pd/TiO2-VO and CuPd/TiO2-VO catalysts with adsorption energies of -1.79, -1.75 and -1.71 eV, respectively. Furthermore, the C-C coupling reaction does not occur on the Cu and PdCu cluster sites of the M/TiO2-VO catalysts, indicating the inactivity of these sites for C2 products. However, Pd/TiO2, CuPd/TiO2 and M/TiO2-VO interfaces favor the C-C coupling reaction and therefore have the potential to reduce CO2 to C2 products. Additionally, the Gibbs free energy calculations reveal that the surface oxygen vacancy improves the OCCO hydrogenation to C2H4 at the CuPd/TiO2-VO interface. [ABSTRACT FROM AUTHOR]

The ginkgo leaf-derived graphitic-N-doped porous carbon was fabricated by one-step carbonization in the presence of KOH agent. The morphology, surface functional groups, element state and porous structure of the obtained carbon were investigated systematically. Compared with the carbon samples by ginkgo-leaf carbonization and KOH post-activation (two-step), the one-step activated porous carbon exhibits high graphitic-N content and good electric conductivity. The conductive-agent-free carbon sheet was made successfully and the resultant carbon electrode possesses good conductivity and excellent electrochemical properties, with the specific capacitance of 176.1 F g-1. When being applied for capacitive deionization, the desalination amount of the electrode arrived at 16.5 mg g-1. Meanwhile, the salt adsorption rate is very rapid, with the average salt adsorption rate reaching 1.5 mg g-1 min-1. This work provides an easy and environmentally benign route for the synthesis of the conductive carbon from natural raw materials for highly efficient capacitive deionization. [ABSTRACT FROM AUTHOR]