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A novel magnetic Fe3O4@SiO2@Bi2O2CO3/rGO composite comprising of uniform core-shell-structured Fe3O4@SiO2@Bi2O2CO3 microspheres mounted on reduced graphene oxide (rGO) sheets was successfully fabricated by using a facile hydrothermal method. The adsorption–desorption isotherm of Fe3O4@SiO2@Bi2O2CO3/rGO belonged to type IV with an H4-type hysteresis loop. The specific surface areas and magnetization saturation value (Ms) of Fe3O4@SiO2@Bi2O2CO3/rGO (x = 0.15 g) were 102.12 m2/g and 25.4 emu/g, respectively. Fe3O4@SiO2@Bi2O2CO3/rGO (x = 0.15 g) exhibited remarkable photocatalytic degradation activity and mineralization effect for MO and decolorization performance for the mixed solution of MO, Rh B, and MB. MO degradation by Fe3O4@SiO2@Bi2O2CO3/rGO conformed to a first-order kinetic reaction, and the corresponding kapp value was 0.05553 min−1. A suitable amount of rGO in Fe3O4@SiO2@Bi2O2CO3/rGO could decrease the energy band gap, inhibit the recombination of photo-induced electron/hole (e−/h+) pair, and broaden and enhance the response of the catalyst to visible light, thereby enhancing the visible-light catalytic degradation of organic dyes. The active species produced in the photocatalysis included •O2−, •OH, and h+, with •O2− being the dominant active species. The as-prepared photocatalyst also showed excellent magnetic separation performance and stability. Results show that the as-prepared Fe3O4@SiO2@Bi2O2CO3/rGO composite is a promising photocatalyst with considerable application potential in organic dyes removal.

Orthorhombic β-LiVOPO4/ketjen black composite is obtained via a two-step chemical synthesis. In the first step, Li3V2(PO4)3-V2O3/ketjen black precursor is obtained by spray-drying process and subsequent heat treatment. Solvent-thermal oxidation of the precursor results in the complete formation of β-LiVOPO4/ketjen black composite. The synthesized composite is characterized by means of X-ray diffraction, scanning electron microscopy, nitrogen sorption, and electrochemical tests. Galvanostatic charge–discharge cycling of the composite shows an initial discharge specific capacity of 305, 289, 276, 242, 157, and 77 mAh·g−1 at C/20, C/10, C/5, C/2, 1C, and 2C rate in a voltage window of 2.0–4.5 V, respectively. At higher current rates, although it exhibits good retention of discharge capacity, the capacity is found to reduce with increasing current rates. The composite displays excellent cycling performance at a current rate of C/5 up to 50 cycles, which yields a high specific capacity of 245 mAh·g−1 at the end of the 50th cycle and a small capacity fading of 0.13% per cycle.

A novel magnetic Fe3O4@SiO2@BiFeO3/rGO composite was successfully fabricated via a facile hydrothermal method. This composite consisted of flower-like core-shell structured Fe3O4@SiO2@BiFeO3 microspheres mounting on reduced graphene oxide (rGO) nanosheets. The specific surface areas, magnetization saturation value (Ms), and band gap energy (Eg) of Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 139.26 m2/g, 20.3 emu/g, and 1.91 eV, respectively. Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) exhibited remarkable ability to photocatalytically degrade ciprofloxacin (CIP), tetracycline hydrochloride (TC-H), methylene blue (MB), and decolorize a mixed solution of MB, methyl orange (MO), and rhodamine B (Rh B); CIP, TC-H, and MB degradation by Fe3O4@SiO2@BiFeO3/rGO conformed to a first-order kinetic reaction, and the corresponding kapp values by Fe3O4@SiO2@BiFeO3/rGO (x = 0.15 g) were 0.04211, 0.02792, and 0.05967 min−1, respectively. Excellent magnetic separation performance, recyclability, and stability were also observed. A suitable amount of rGO to the as-prepared photocatalyst could decrease the Eg, accelerate the transfer of photogenerated electrons (e−), suppress the recombination of photo-generated e−–hole (h+) pairs, and enhance the visible-light response of the catalyst. The •OH is the dominant active species during photocatalysis. This work suggests a promising strategy to synthesize photocatalysts with enhanced ability to catalytically degrade organic pollutant under visible light and excellent recyclability.

The MnO2/Micro-nano Ni-filled Ni foam (MNFNF) hybrids were systematically studied as supercapacitor electrodes. Micro-nano Ni-filled Ni foam (MNFNF) was prepared via a facile NiC2O4·2H2O coating process on foam, followed by sintering treatment, and then employed as substrate for electrodeposition of MnO2. The morphology of the MNFNF substrate exhibited an obviously second-porous structure, deriving from dehydration, decarboxylation, and the lattice contraction occurred in the sintering treatment process of NiC2O4·2H2O. The structure of pores was irregular with 0.05~2 μm in diameter, and the pore walls were composed of nanoparticles with 200~500 nm in diameter. Such porous MNFNF not only provided a conductive network to enhance the charge transport and mass transfer in the electrochemical process but also achieved a large MnO2 mass loading capacity. Electrochemical test showed the MnO2/MNFNF electrode exhibited a mass specific capacitance (SC) of 723.7 F g−1 and an areal specific capacitance of 1.16 F cm−2 at a current rate of 0.25 A g−1. The asymmetric supercapacitor device based on the MnO2/MNFNF electrode and active carbon electrode could supply an energy density of 24.5 Wh kg−1 at the maximum power density of 4.4 kW kg−1. Meanwhile, the supercapacitor device also exhibited a good cycling stability along with 93.2% specific capacitance retained after 5000 cycles. These results demonstrated that the MnO2/MNFNF electrode could be one of the potential electrode material for energy storage applications.

The commercial application of lithium-sulfur (Li-S) battery is hampered by the insulating characteristic and dissolution problem of sulfur and lithium polysulfides. Herein, a mesoporous TiO2@PPy material has been fabricated to act as the chemical immobilizer for sulfur species in Li-S battery. In the structure, PPy layer is covered uniformly on surface of the mesoprous TiO2, forming a core-shell structure. The well-developed mesopores act as the reservoir for sulfur, while the PPy layer improves the conductivity of material and further prevents diffusion of soluble polysulfides. The synthesized TiO2/S@PPy composite delivers an improved rate capability and cycling stability, with an initial discharge specific capacity of 1013.7 mAh g−1 at 0.1 C. In addition, the composite reserves a high capacity of 567.0 mAh g−1 after 300 cycles at 0.5 C, with a decreasing rate of 0.103% per cycle.

A two-component material (Fe3O4@CaSiO3) with an Fe3O4 magnetite core and layered porous CaSiO3 shell from calcium nitrate and sodium silicate was synthesized by precipitation. The structure, morphology, magnetic properties, and composition of the Fe3O4@CaSiO3 composite were characterized in detail, and its adsorption performance, adsorption kinetics, and recyclability for Cu2+, Ni2+, and Cr3+ adsorption were studied. The Fe3O4@CaSiO3 composite has a 2D core–layer architecture with a cotton-like morphology, specific surface area of 41.56 m2/g, pore size of 16 nm, and pore volume of 0.25 cm3/g. The measured magnetization saturation values of the magnetic composite were 57.1 emu/g. Data of the adsorption of Cu2+, Ni2+, and Cr3+ by Fe3O4@CaSiO3 fitted the Redlich–Peterson and pseudo-second-order models well, and all adsorption processes reached equilibrium within 150 min. The maximum adsorption capacities of Fe3O4@CaSiO3 toward Cu2+, Ni2+, and Cr3+ were 427.10, 391.59, and 371.39 mg/g at an initial concentration of 225 mg/L and a temperature of 293 K according to the fitted curve with the Redlich–Peterson model, respectively. All adsorption were spontaneous endothermic processes featuring an entropy increase, including physisorption, chemisorption, and ion exchange; among these process, chemisorption was the primary mechanism. Fe3O4@CaSiO3 exhibited excellent adsorption, regeneration, and magnetic separation performance, thereby demonstrating its potential applicability to removing heavy metal ions.

The adsorption characteristic and mechanism of poly(N1,N1,N3,N3-tetraallylpropane-1,3-diaminium chloride) (PTAPDAC) toward Cr(VI) ions were systematically investigated. Results showed that the remo...

The preparation and capacitance performances of Mn (OH)2@ secondary porous Ni nano-architecture foam (Mn (OH)2@SPNiNF) hybrids are systematically studied. The SPNiNF structure is simply obtained via a NiC2O4·2H2O in situ growing process on Ni foam surface, combined with a thermally treated process under Ar gas. Then, a layer of Mn (OH)2 film was electrodeposited onto the above SPNiNF sheet by applying a galvanostatical technique. It is shown that the SPNiNF sheet is composed of interconnected nanoparticles with a diameter range of 100–200 nm. The fabricated Mn (OH)2@SPNiNF electrode exhibited a high specific capacitance of 532.7 F g−1 and an areal capacitance of 906 m F cm−2 at a current density of 0.5 A g−1. The Mn (OH)2@SPNiNF electrode also exhibited a low ions diffusion resistance and a good cycling performance along with 85.7% specific capacitance retained after 5000 cycles. An asymmetric Mn (OH)2@SPNiNF //AC super capacitor exhibited an energy density of 69.1 Wh kg−1 at a power density of 0.6 kW kg−1. These results demonstrated that the Mn (OH)2@SPNiNF was a promising electrode material for supercapacitors.

Thiol-functionalized mesoporous calcium silicate (MCS-SH) was synthesized using post-grafting with calcium nitrate tetrahydrate and sodium metasilicate nonahydrate as raw materials, cetyl trimethyl ammonium bromide as template, and (3-mercaptopropyl)trimethoxysilane as modifying agent. The structure and composition were characterized using X-ray diffraction, Fourier-transform infrared spectroscopy, Brunauer–Emmett–Teller surface analysis, thermogravimetry–differential thermal analysis, scanning electron microscopy, transmission electron microscopy, and energy-dispersive X-ray spectrometry. The adsorption performance and thermodynamic and kinetic characteristics of MCS-SH for Cd2+, Cu2+, Pb2+, and Cr3+ were investigated. Results showed that MCS-SH possessed a slit-pore structure with a specific surface area of 129.32 m2 g−1 and pore size that was mainly distributed in 5–49 nm, which reduced by 28.81 m2 g−1 and 2 nm compared with those of unmodified mesoporous calcium silicate (MCS), respectively. The amount of SH grafted to MCS-SH was 0.4594 mmol g−1, according to the determined sulfur content. The maximum adsorption capacities for Cd2+, Cu2+, Pb2+, and Cr3+ were 601.51, 509.56, 618.09, and 334.81 mg g−1 at 293 K, respectively, which were much higher than those reported in the literature, and follow the order of Pb2+ > Cd2+ > Cu2+ > Cr3+. The equilibrium data of the four heavy metal ions adsorbed by MCS-SH fitted the Langmuir model and, especially, the Redlich–Peterson model well. The adsorption processes were all endothermic, entropy increasing, and spontaneous. The adsorption of MCS-SH for Cd2+, Cu2+, Pb2+, and Cr3+ was rapid and attained equilibrium within 60 min. The adsorption kinetics can be well fitted by the pseudo-second-order model, and the adsorption activation energy followed the order of Cr3+ (29.7526 kJ mol−1) > Pb2+ (21.5840 kJ mol−1) > Cu2+ (19.6988 kJ mol−1) > Cd2+ (18.5377 kJ mol−1). The adsorption mechanisms include physical adsorption, chemical adsorption (especially surface complexing adsorption), and ion exchange, with chemical adsorption being the dominant mechanism. MCS-SH exhibited an excellent performance as adsorption material for Cd2+, Cu2+, Pb2+, and Cr3+.

Novel magnetic core-shell structured Fe3O4@SiO2@BiFeO3–sepiolite microspheres were fabricated via a facile hydrothermal method. The as-prepared microspheres comprised a Fe3O4@SiO2 magnetic core with a strong response to external fields and a porous BiFeO3/sepiolite composite functional layer. The specific surface area, magnetization saturation value (Ms), and band gap energy (Eg) of Fe3O4@SiO2@BiFeO3–sepiolite (x = 0.4 g) were 126.68 m2/g, 18.2 emu/g, and 2.09 eV, respectively. A suitable amount of sepiolite in Fe3O4@SiO2@BiFeO3–sepiolite could improve the microstructure of the photocatalyst through the interface effect between the sepiolite and the formed BiFeO3, which can enlarge the specific surface area and thus increase the absorption of light and the adsorption of pollutants, decrease the Eg of the as-prepared photocatalyst, and improve the separation and inhibit the recombination of photogenic electron and hole (e−/h+) pairs, thereby expediting the photocatalytic degradation of pollutants. The as-obtained Fe3O4@SiO2@BiFeO3–sepiolite (x = 0.4 g) exhibited a remarkable photocatalytic degradation performance for ciprofloxacin (CIP), tetracycline hydrochloride (TC-H), and methylene blue (MB) and an excellent decolorization for the mixed solution of methyl orange (MO), rhodamine B (Rh B), and MB under visible-light irradiation. In addition, the as-obtained photocatalyst demonstrated excellent magnetic separation performance, recyclability, and stability. The active species produced during the photocatalysis included OH, O2−, and h+, with OH being the dominant active species. Such a well-structured core-shell photocatalyst has remarkable potential for numerous applications in treating organic wastewater.

A novel magnetic core–shell architecture Fe3O4@Sio2@Bi2O2CO3–sepiolite composite was successfully fabricated by coating a layer of Bi2O2CO3–sepiolite mixture onto Fe3O4@Sio2 cores through a facile hydrothermal method. The photodegradation rates of ciprofloxacin (CIP) and tetracycline hydrochloride (TC-H) were 92.1% and 100%, respectively. A suitable amount of sepiolite in Fe3O4@Sio2@Bi2O2CO3–sepiolite can enlarge the specific surface area, promote the formation of an excellent photocatalyst structure, and generate a strong interfaces effect between the sepiolite and Fe3O4@Sio2@Bi2O2CO3. This condition endowed the as-prepared photocatalyst with high light harvesting capability and abundant active reaction sites. It also boosted the separation of photogenic e − /h + pairs. Moreover, this condition inhibited the recombination of e − /h + pairs and decreased the energy band gap, thereby enhancing the visible light catalytic degradation of antibiotics. The active species produced during photocatalysis included h + and •O 2 − , with h + as the dominant active species. The as-prepared photocatalyst exhibited excellent photocatalytic degradation activity, magnetic separation performance, recyclability, and stability.

A Mn 3 O 4 /MnOOH nanocomposite was synthesized through a sonochemical process and used for supercapacitor applications. The obtained samples were characterized using a transmission electron microscope (TEM), a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and selected-area electron diffraction (SAED). The electrochemical performance of the Mn 3 O 4 /MnOOH nanocomposite was investigated as supercapacitor electrode material through cyclic voltammetry (CV), galvanostatic charge/discharge (GC/D) and electrochemical impedance spectroscopy (EIS). Results indicated that ultrasonic time strongly influenced the MnOOH contents in the nanocomposite. The Mn 3 O 4 /MnOOH nanocomposite electrode of 0.22 MnOOH content provided a high specific capacitance of 307.8 F g −1 as well as excellent cycling stability (2% decay after 2000 cycles). Furthermore, the symmetric supercapacitor based on Mn 3 O 4 /MnOOH nanocomposite has a reasonable energy density of 10.6 W h kg −1 and a high power density of 7.4 kW kg −1 . The excellent capacitive performance of the Mn 3 O 4 /MnOOH nanocomposite is due to synergistic effect between the Mn 3 O 4 and the MnOOH.

Novel dithiocarbamate (DTC)-modified crosslinked poly(β−cyclodextrin-co-triethylenetetramine) microspheres (DTC-PCDTTM) possessing a particle size distribution of 141 μm with a span value of 0.65 were fabricated and evaluated by Cu2+−MO/TB binary-component systems. DTC-PCDTTM shows excellent simultaneous adsorption performance for Cu2+ and methyl orange (MO) or thymol blue (TB) at a DTC graft ratio of 0.21; it also exhibits eminent regeneration and recyclability. The adsorption isotherm data of DTC-PCDTTM for Cu2+ and MO or TB in Cu2+−MO/TB binary-component systems can be described by the Freundlich and Langmuir models, respectively. The adsorption kinetic data of Cu2+, MO, and TB by DTC-PCDTTM are related to the pseudo-second-order kinetic model. The adsorption is a process of spontaneous endothermic entropy increment. The coordination, electrostatic attraction, and the host−guest interaction of β−cD moieties with contaminants are the primary mechanisms for Cu2+, MO, and TB adsorption. In the Cu2+−MO/TB binary-component systems, competitive adsorption is effectively avoided, and Cu2+ shows good synergistic effects with MO and TB.

A novel magnetic core-shell Fe3O4@[epichlorohydrin-co-triethylenetetramine]n-graft-CSSNa microspheres (Fe3O4@[ECH-co-TETA]n-g-CSSNa) was successfully fabricated through adhesion and subsequent crosslinking of poly(epichlorohydrin-co-triethylenetetramine) copolymer ([ECH-co-TETA]n) on Fe3O4 microspheres and then grafting with dithiocarbamate (−CSS−). The as-prepared Fe3O4@[ECH-co-TETA]n-g-CSSNa microspheres presented an uniform core-layer architecture with approximately 600 nm of particle sizes and 50 nm of coating layer. The −CSS− content of Fe3O4@[ECH-co-TETA]n-g-CSSNa was 1.9257 mmol g−1, and its measured magnetization saturation value was 50.51 emu g−1. Benefiting from its unique microstructure, the resulting adsorbent exhibited high adsorption efficiencies of 293.85, 256.69, 277.93, and 225.07 mg g−1 for Pb2+, Cd2+, Cu2+, and Zn2+ in the pH range of 5.00–8.00 at 293 K, respectively, and rapid adsorption speed of reaching equilibrium within 10 min. Meanwhile, the resulting adsorbent could be easily regenerated at least five cycles with a little capacity loss and exhibited excellent magnetic separation performance. The adsorption data fitted the Langmuir and pseudo-second-order models well, and the adsorption activation energies for Pb2+, Cd2+, Cu2+, and Zn2+ were 26.6359, 15.6302, 26.5152, and 21.1095 kJ mol−1, respectively. All adsorption were spontaneous endothermic processes featuring an entropy increase, involving electrostatic attraction, physisorption, and chemisorption (especially ion exchange and surface complexing adsorption). In chemisorption, S, N, and O in the active layer of Fe3O4@[ECH-co-TETA]n-g-CSSNa were all involved in the formation of a coordination bond and particularly formed a symmetrical S-coordinated four-membered ring of (–CSS−)2M2+. Our work suggests a promising strategy for the rapid and highly efficient removal of heavy metal ions from wastewater.

Problems associated with water eutrophication due to high phosphorus concentrations and related environmentally safe solutions have attracted wide attention. A novel bis(diallyl alkyl tertiary ammonium salt) polymer, particularly poly(N1,N1,N6,N6-tetraallylhexane-1,6-diammonium dichloride) (PTAHDADC), was synthesized and characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, scanning electron microscopy, mercury intrusion method, and thermogravimetric analysis. The adsorption characteristics in phosphorus were evaluated in dilute solution, and the recycling properties of PTAHDADC were investigated. Results showed that PTAHDADC possessed macropores with a size distribution ranging from 30 to 130 μm concentrating at 63 μm in diameter and had 46.52% of porosity, excellent thermal stability below 530K, and insolubility. PTAHDADC could effectively remove phosphorus at pH = 7–11 and had a removal efficiency exceeding 98.4% at pH = 10–11. The adsorption equilibrium data of PTAHDADC for phosphorus accorded well with the Langmuir and pseudo-second-order kinetic models. Maximum adsorption capacity was 52.82 mg/g at 293 K. PTAHDADC adsorbed phosphorus rapidly and reached equilibrium within 90 min. Calculated activation energy Ea was 15.18 kJ/mol. PTAHDADC presented an excellent recyclability with only 8.23% loss of removal efficiency after five adsorption–desorption cycles. The morphology and structure of PTAHDADC slightly changed as evidenced by the pre- and post-adsorption of phosphorus, but the process was accompanied by the partial deprotonation of the (–CH2)3NH+ group of PTAHDADC. The adsorption was a spontaneous exothermic process driven by entropy through physisorption, electrostatic attraction, and ion exchange. Survey results showed that PTAHDADC was a highly efficient and fast-adsorbing phosphorus-removal material prospective in treating wastewater.

The adsorption characteristic and mechanism of poly(N

A two-component material (Fe

LiCoBO3/ketjen black composites were prepared at a moderate temperature of 450 °C by a molten salt method using eutectic mixtures of LiCl and KCl as the reaction medium and ketjen black as a carbon source. The monoclinic structure and spherical morphology are respectively confirmed by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The electrochemical behavior was studied by galvanostatic charge–discharge and cyclic voltammetry tests. At a rate of C/20, the composite delivered an initial specific capacity of 48 mA h g−1 and a discharge specific capacity of 40 mA h g−1 at the 25th cycle, indicating a stable cycling performance. However, rate capability for the composite needs to be further improved.

Porous α-LiVOPO4/C composite was prepared by the solution combustion synthesis method followed by annealing at 500°C for a short annealing duration of just 50 min. The synthesised material was characterised by XRD, SEM, TEM, N2 adsorption–desorption isotherms and charge–discharge tests. When tested at 0.05C rate for Li ion insertion properties, α-LiVOPO4/C composite exhibits good cycle capability with an negligible capacity degradation for the first 31 cycles. However, it shows poor rate capability with initial discharge specific capacities of 127.6 mAh g− 1 (0.05C), 109.1 mAh g− 1 (0.1C) and 74.9 mAh g− 1 (0.2C), respectively.

Mesoporous calcium silicate (MCS) was prepared from calcium nitrate and sodium silicate by ultrasonic-assisted template method. The effects of different templates (sodium dodecyl sulfate, cetyl trimethyl ammonium bromide, P123, and cetyl trimethyl ammonium bromide–tetramethyl ammonium hydroxide) on the pore size and surface topography of MCS were investigated. Calcium silicate synthesized was characterized by X-ray diffraction, scanning electron microscopy, the Brunauer–Emmett–Teller method, and Fourier transform infrared spectroscopy. The adsorption performances of the MCS synthesized for Cd2+ were also investigated. Results showed that the MCS synthesized using cetyl trimethyl ammonium bromide as template under ultrasonic treatment acquired a mesoporous slit-pore structure with a specific surface area of 244.32 m2 g−1 and pore size (DBJH) of 11.2 nm. MCS showed extremely high adsorption capacity for Cd2+ at pH 5.0–7.5, and the adsorption capacity for Cd2+ was 509.91 mg g−1 at 293 K, which was much higher than those of the adsorbents in literature. The equilibrium adsorption data of MCS for Cd2+ all fitted the Langmuir and Redlich–Peterson models, and more closely with the Redlich–Peterson model. The adsorption of MCS toward Cd2+ was a spontaneous endothermic reaction driven by increased entropy involving both physical and chemical modes. The adsorption of MCS for Cd2+ was better described by the pseudo-second-order model than by the pseudo-first-order model, with an activation energy of 13.4327 kJ mol−1. Thus, it is evident that MCS can be a promising excellent adsorbent for the treatment of Cd2+-containing wastewater.

Monoclinic/hexagonal mixed-phase LiMnBO 3 /C composites have been prepared by the impregnation-precipitation method using ketjen black (KB) with 3D conductive network as both template and conductive framework. The synthesized products are characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), nitrogen sorption and electrochemical tests. Morphology studied by SEM and nitrogen sorption shows that LiMnBO 3 particles are embedded in the nanostructured carbon networks. The LiMnBO 3 /C electrodes deliver an initial discharge specific capacity of 150, 137, 121 and 85 mAh g −1 at C/20, C/10, C/5 and C/2 rate, respectively. Although the capacity for the LiMnBO 3 /C electrode decreases considerably with increasing rate, stable cycling performance is obtained for all the four rates.

Mesoporous calcium silicate (MCS) was synthesized by template method using calcium nitrate tetrahydrate and sodium metasilicate nonahydrate as raw materials, cetyl trimethyl ammonium bromide-tetramethyl ammonium hydroxide as template. Its structure was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunuaer–Emmett–Teller (BET) surface analysis, and scanning electron microscopy (SEM). The adsorption characteristics of MCS for Pb2+ were investigated. Results show that MCS possesses a slit-pore structure with a specific surface area of 131.22 m2·g−1 and pore size (DBJH) of 20 nm. The maximum adsorption capacities for Pb2+ is 437.94 mg·g−1 at 293 K, which is much higher than those reported in the literature. The equilibrium data of Pb2+ adsorbed by MCS fitted the Langmuir and Redlich–Peterson models, and more closely with the Redlich–Peterson model. The adsorption of MCS for Pb2+ was a spontaneous endothermic reaction driven by increased entropy involving both physical and chemical modes. Thus, it is evident that MCS can be a promising excellent adsorbent for the treatment of Pb2+-containing wastewater.

A three-component magnetic material, namely, Fe3O4@SiO2@CaSiO3, which featuring an Fe3O4@SiO2 core and a layered porous CaSiO3 shell, was synthesized via precipitation and utilized as an adsorbent to remove Ag+ from wastewater. The structure, morphology, composition, and magnetic properties of this material were analyzed by a series of characterization techniques, and its adsorption efficiency, adsorption thermodynamics, kinetic characteristics, and recyclability were investigated in detail. The magnetic Fe3O4@SiO2@CaSiO3 composite possessed a core–shell structure, with a cotton-like morphology, a specific surface area of 75.97 m2·g−1, pore size of 11.4 nm, pore volume of 0.36 cm3·g−1, and magnetization saturation of 60.5 emu·g−1. The adsorption equilibrium data of Ag+ adsorption by Fe3O4@SiO2@CaSiO3 fitted the Redlich–Peterson model well, and the equilibrium adsorption capacity of the material for Ag+ reached 127.84 mg·g−1 at an initial concentration of 225 mg·L−1 and temperature of 293 K. Kinteic studies showed that the adsorption process conformed well to the pseudo-second-order model and reached equilibrium within 150 min. The adsorption process was endothermic, with an activation energy of 8.475 kJ·mol−1 and accompanied by Ag O bonding and Ca2+ release. Therefore, the adsorption mechanism involved in Ag+ removal includes not only physisorption and ion exchange but also chemisorption, which is controlled by surface OH and O groups. The percentage of Ag+ removal tended to stabilize after five cycles of Fe3O4@SiO2@CaSiO3 reuse and but decreased by only 14.34%. Synthesized Fe3O4@SiO2@CaSiO3 exhibited excellent adsorption, regeneration, and magnetic separation performance. Thus, the synthesized Fe3O4@SiO2@CaSiO3 may potentially be applied to remove Ag+.

The practical application of Li metal in rechargeable batteries is seriously hindered by its irregular dendrite growth resulting in inferior cycling efficiency and poor safety. Herein, a multifunctional artificial solid electrolyte interphase (SEI) layer is constructed on lithium surface via chemical reactions between lithium metals and allyl glycidyl ether (AGE). The protected layer is mainly composed of cross-linked polyethylene chains and polyethylene oxide moieties, which significantly improved the cycling performance of Li|Li symmetric cells and high voltage Li|NCM523 (4.5 V) cells in the electrolyte of 1 M LiPF6 in EC/DMC/EMC (1:1:1, by wt.). Electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM) measurements confirm that the protected layer could reduce the morphology changes and suppress the parasitic reactions of lithium anodes effectively. A probable mechanism based on polymerization and cross-linking reactions of AGE is proposed for the formation of artificial SEI layer. These results demonstrated that the multifunctional artificial solid electrolyte interphase (SEI) layer have considerable potential application to protect lithium metal anode.

Mesoporous calcium silicate (MCS) was synthesized using the ultrasonic-assisted template method by using calcium nitrate tetrahydrate and sodium metasilicate nonahydrate as raw materials and cetyltrimethylammonium bromide–methenamine as the template. X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and Brunauer–Emmett–Teller method were used for the characterization of MCS. The surface charge characteristics of MCS and its adsorption characteristics for Ni2+, Cu2+, Zn2+, Pb2+, Mn2+, and Cd2+ were also investigated. MCS formed through the accumulation of thin flakes with various shapes and exhibited a slit-pore structure and uneven surfaces with a specific surface area of 239.41 m2 g−1 and a pore size of 11.74 nm. MCS possessed a distinct, wide, near-zero potential point pH range of 5–9, and the point of zero charge, pHPZC, reached 8.6 ± 0.1. The MCS surface was alkaline, and MCS exhibited excellent acid–base buffering capacity at pH 5–11. The high adsorption capacity of MCS for the six heavy metal ions at pH 5.0–7.5 followed the order Pb2+ > Cd2+ > Zn2+ > Cu2+ > Ni2+ > Mn2+ (in mgg−1). The adsorption for the six heavy metal ions occurred rapidly and attained equilibrium within 120 min. The order of adsorption activation energy was Mn2+ > Zn2+> Ni2+ > Pb2+ > Cu2+ > Cd2+. The adsorption processes of the six heavy metal ions were all endothermic, entropy increasing, and spontaneous. MCS remained stable during adsorption, but the adsorbed heavy metal ions underwent transformation, especially Cu2+, Pb2+, and Cd2+, which formed new phases. The adsorption mechanisms included physical adsorption, chemical adsorption (particularly surface complexing adsorption and surface precipitation), and ion exchange. MCS exhibits an excellent adsorption and recycling performance and the potential to become an adsorption material with excellent properties for heavy metal ions.

Nanobioactive glass (NBG) particles were synthesised via sol–gel method and characterised by transmission electron microscopy (TEM) and X-ray diffraction (XRD). The new composite biomateria...

LiVOPO4/carbon composite materials were prepared at a moderate temperature of 400°C by oxalic acid assisted sol-gel technique and acetylene black acting as a carbon source. The as synthesized composite materials were characterized by XRD, SEM, galvanostatic charge–discharge and CV measurements. When tested at 0.1 C rate for Li ion insertion properties, α-LiVOPO4/ carbon composite material exhibits good cycle capability with an average capacity degradation of just 0.05 mAh/g per cycle. Additionally, when the various discharge rates were applied progressively for each of ten cycles, it shows excellent rate capability with initial discharge capacities of 138 mAh/g (0.1 C), 134 mAh/g (0.2 C), 108 mAh/g (0.5 C) and 83 mAh/g (1 C), respectively, indicating that carbon modification could enhance the electronic conductivity of LiVOPO4.

The microspheres based on gelatin (Gel) and chitosan (Cs) were prepared by a water-in-oil (W/O) emulsion crosslinking method using glutaraldehyde (GA) as a crosslinker. 5-Fluorouracil (5-FU), as an anticancer drug, was successfully loaded into the Gel/Cs microspheres. The release behavior of 5-FU was investigated with the microspheres acting as carriers for controlled release. Scanning electron microscopy (SEM) showed the formation of the microspheres is spherical with the size around 300 μm. The release patterns depend on the composition of Gel/Cs microspheres, content of crosslinker and drug content in the microspheres. The cumulative drug release of 5-FU from the microspheres decreased with increasing GA content; however, the cumulative drug release increased with increasing Gel mass ratio and 5-FU content in the microspheres. The results of 5-FU release kinetics for Gel/Cs microspheres indicated Fickian diffusion.

Monoclinic structure Li3V2(PO4)3/C composite powders are synthesized via a novel homogeneous mixing route followed by a one-step heat treatment. The composites were characterized by X-ray diffraction (XRD) and galvanostatic charge/discharge, CV measurements. The influence of the heat treatment on the electrochemical properties of Li3V2(PO4)3/C composites was investigated. To examine the effect of residual carbon content on the properties of the composites, six samples with 1.2, 2.3, 3.4, 4.4, 5.8, and 7.0 wt% carbon were prepared. The sample with 4.4 wt% carbon exhibited good cycling performance and rate capability in the range of 3.0–4.8 V.

The effects of Al doping on the electrochemical properties of NaVPO4F as a cathode material for sodium-ion batteries were investigated. Al-doped NaV1−xAlxPO4F (x=0, 0.02) samples were prepared by a simple high temperature solid-state reaction involving VPO4 and NaF for the application of cathode material of sodium-ion batteries. The crystal structure and morphology of the material were studied by Flourier-infrared spectrometry(FT-IR), X-ray diffractometry(XRD) and scanning electron microscopy(SEM). The results show that NaV1−xAlxPO4F (x=0, 0.02) has a typical monoclinic structure. The effects of Al doping on the performance of the cathode material were analyzed in terms of the crystal structure, charge-discharge curves and cycle performance. It is found that NaV0.98Al0.02PO4F shows an improved cathodic behavior and discharge capacity retention compared with the undoped samples in the voltage range of 3.0–4.5 V. The electrodes prepared from NaV0.98Al0.02PO4F deliver an initial discharge capacity of 80.4 mA·h/g and an initial coulombic efficiency of 89.2%, and the capacity retention is 85% after 30th cycle. Though the Al-doped samples have lower initial capacities, they show better cycle performance than Al-free samples.

The key to development of sodium-ion battery is the preparation of cathode/anode materials. Cr doped NaV 1− x Cr x PO 4 F ( x = 0, 0.04, 0.08) were prepared by the high temperature solid-state reaction for the application of cathode material of sodium-ion batteries. The structures and morphologies of the cathode materials were characterized by Flourier-infrared spectra (FT-IR), X-ray diffraction (XRD) and scanning electron microscope (SEM). The effects of Cr doping on performances of the cathode materials were analyzed in terms of the crystal structure, charge–discharge curves and cycle performances. The results showed that the as-prepared Cr-doped materials have a better cycle stability than the un-doped one, an initial reversible capacity of 83.3 mAh g −1 can be obtained, and the first charge–discharge efficiency is about 90.3%. In addition, it was also observed that the reversible capacity retention of the material is still 91.4% in the 20th cycles.

The kinetic properties of monoclinic lithium vanadium phosphate were investigated by potential step chronoamperometry (PSCA) and electrochemical impedance spectroscopy (EIS) method. The PSCA results show that there exists a linear relationship between the current and the square root of the time. The D Li values of lithium ion in Li 3- x V 2 (PO 4 ) 3 under various initial potentials of 3.41, 3.67, 3.91 and 4.07 V (vs Li/Li + ) obtained from PSCA are 1.26 × 10 − 9 , 2.38 × 10 − 9 , 2.27 × 10 − 9 and 2.22 × 10 − 9 cm 2 ·s − 1 , respectively. Over the measuring temperature range 15–65 °C, the diffusion coefficient increased from 2.67 × 10 − 8 cm 2 ·s − 1 (at 15 °C) to 1.80 × 10 − 7 cm 2 ·s − 1 (at 65 °C) as the measuring temperature increased.

The chemical diffusion of lithium ion in Li3V2(PO4)3 were investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The CV results show that there exists a linear relationship between the peak current (ip) and the square root of the scan rate (ν1/2). The impedance spectrum exhibits a single semicircle and a straight line in a very low frequency region. A linear behavior was observed for every curve of the real resistance as a function of the inverse square root of the angular frequency in a very low frequency region. The obtained chemical diffusion coefficient from EIS measurements varies within 10− 9 to 10− 8 cm2·s− 1, in good agreement with those from CV results.

Monoclinic Li 3 V 2 (PO 4 ) 3 /C composite materials are synthesized from a sucrose-containing precursor by one-step heat treatment. As-prepared composites are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetric (CV) technology and charge/discharge measurement. XRD patterns show that Li 3 PO 4 impurity phase appears in the sample synthesized at 600 °C and pure Li 3 V 2 (PO 4 ) 3 samples can be obtained when the sintered temperature is higher than 700 °C. The sample synthesized at 700 °C presents the highest initial capacity of 170 mAh·g − 1 (at C/5 rate), and exhibits better cycling stability (142 mAh g − 1 at 50th cycle at C/5 rate) and better rate capability (137 mAh·g − 1 at 30th cycle under 1 C rate) in the voltage range of 3.0–4.8 V.

Monoclinic lithium vanadium phosphate was synthesized by a low temperature route. NH4VO3, LiOH, (NH4)2HPO4 and sucrose were used as starting materials to prepare a precursor, and Li3V2(PO4)3/C composite was finally obtained by sintering the precursor. X-ray diffraction results show that Li3V2(PO4)3 sample is monoclinic structure. The initial discharge capacities of Li3V2(PO4)3/C composite materials are 125 mA h g− 1 in the voltage range of 3.0–4.3 V, 164 mA h g− 1 in the voltage range of 3.0–4.8 V, respectively. The discharge capacity after 30 cycles at two voltage windows was held to be 122 and 142 mA h g− 1, respectively.

The CuV2O6 cathode material was successfully synthesized using the NH4VO3 and the alkaline copper carbonate (CuCO3·Cu(OH)2·xH2O, malachite) as the starting reagents by a citrate sol–gel route. The structures and electrochemical properties of CuV2O6 synthesized at different temperature were characterized by X-ray diffraction (XRD), thermogravimetry/differential thermogravimetry (TG/DTG), scanning electron microscopy (SEM) and electrochemical measurements. The results showed that the sample prepared at 550 °C had small particle size, and thus revealed higher initial discharge capacity (403 mAh g−1) and better cycle performance than that prepared by the conventional solid-state method.