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2023 Volume 39 Issue 3
2023, 39(3): 385-394
doi: 10.11862/CJIC.2023.009
Abstract:
A series of mononuclear rare earth complexes [Ln(pmbp)3(dmbipy)]·C2H5OH, where Ln=Tb (1-Tb), Ho (1-Ho), Er (1-Er) and Tm (1-Tm), were synthesized by using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolinone (Hpmbp) and 4,4'-dimethyl-2,2'-bipyridine (dmbipy) as ligands. Structure characterizations show that the complex is composed of one Ln3+ ion, three pmbp-ions, one dmbipy molecule, and one free ethanol molecule, yielding the [LnO6N2] type structure. The continuous shape measurement (CShM) analyses show that the Ln3+ centers exhibit a distorted triangular dodecahedral geometry. Luminescence measurements showed that all of the complexes exhibit characteristic emission peaks of the corresponding rare earth ions. And it was found that the ligand could sensitize Ho3+ and Er3+ well, while the sensitization of Tb3+ and Tm3+ was weak. In addition, the HOMO and LUMO of Hpmbp ligands, dmbipy ligands, and rare earth complexes were calculated and analyzed by the density functional theory method. It is found that for Tb, Ho, and Tm complexes with an odd number of electrons in the center metal atom, the bond lengths between metal ions and coordination atoms are shorter with the increasing number of electrons in metal ions, while the bond lengths of Er—O and Er—N of 1-Er are between those of 1-Ho and 1-Tm. For 1-Tb, 1-Ho, and 1-Tm, the orbital energy of HOMO and LUMO decreases with increasing electron number, which is consistent with the rule of bond length. For 1-Tb, 1-Ho and 1-Er, the HOMO-LUMO gap increases with the increase of electron number. In addition, the HOMO-LUMO energy gaps of the four complexes are lower than that of the ligands.
A series of mononuclear rare earth complexes [Ln(pmbp)3(dmbipy)]·C2H5OH, where Ln=Tb (1-Tb), Ho (1-Ho), Er (1-Er) and Tm (1-Tm), were synthesized by using 1-phenyl-3-methyl-4-benzoyl-5-pyrazolinone (Hpmbp) and 4,4'-dimethyl-2,2'-bipyridine (dmbipy) as ligands. Structure characterizations show that the complex is composed of one Ln3+ ion, three pmbp-ions, one dmbipy molecule, and one free ethanol molecule, yielding the [LnO6N2] type structure. The continuous shape measurement (CShM) analyses show that the Ln3+ centers exhibit a distorted triangular dodecahedral geometry. Luminescence measurements showed that all of the complexes exhibit characteristic emission peaks of the corresponding rare earth ions. And it was found that the ligand could sensitize Ho3+ and Er3+ well, while the sensitization of Tb3+ and Tm3+ was weak. In addition, the HOMO and LUMO of Hpmbp ligands, dmbipy ligands, and rare earth complexes were calculated and analyzed by the density functional theory method. It is found that for Tb, Ho, and Tm complexes with an odd number of electrons in the center metal atom, the bond lengths between metal ions and coordination atoms are shorter with the increasing number of electrons in metal ions, while the bond lengths of Er—O and Er—N of 1-Er are between those of 1-Ho and 1-Tm. For 1-Tb, 1-Ho, and 1-Tm, the orbital energy of HOMO and LUMO decreases with increasing electron number, which is consistent with the rule of bond length. For 1-Tb, 1-Ho and 1-Er, the HOMO-LUMO gap increases with the increase of electron number. In addition, the HOMO-LUMO energy gaps of the four complexes are lower than that of the ligands.
2023, 39(3): 395-405
doi: 10.11862/CJIC.2023.012
Abstract:
Preparation and electrochemical properties of Schiff base OTTP prepared from o-toluidine and p-benzal-dehyde polymers doped with various proportions of phenanthroline copper complexes. The copper coordination poly-mer [Cu(Phen)Cl2]X-OTTP (X was the molar ratio of Schiff base to phenanthroline copper coordination complex, X=1, 0.8, 0.6, 0.4, 0.2) of Schiff base phenanthroline was synthesized by doping different proportions of phenanthroline copper complexes in Schiff base. The morphology and structure of the products were investigated by scanning elec-tron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), and the electrochemical performance of the electrode materials [Cu(Phen)Cl2]X-OTTP were analyzed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectrum (EIS). The results exhibited that the morphology of the polymer Schiff base changed after doping with phenanthroline copper complexes. After doping, the Schiff base was scaly, with more holes on the surface and the layered structure was destroyed. The matrix π-π stacking was affected. In 6 mol·L-1 KOH electrolyte three-electrode system, [Cu(Phen)Cl2]0.4-OTTP had a high specific capacity of 278 mAh·g-1 at the current density of 0.5 A·g-1. The assembled supercapacitor [Cu(Phen)Cl2]0.4-OTTP//AC (AC=activated carbon) had a power density of 276.99 W·kg-1 at the energy density of 26.16 Wh·kg-1, and kept original specific capacity of 97.13% after 10 000 GCD cycles at current density of 10 A·g-1.
Preparation and electrochemical properties of Schiff base OTTP prepared from o-toluidine and p-benzal-dehyde polymers doped with various proportions of phenanthroline copper complexes. The copper coordination poly-mer [Cu(Phen)Cl2]X-OTTP (X was the molar ratio of Schiff base to phenanthroline copper coordination complex, X=1, 0.8, 0.6, 0.4, 0.2) of Schiff base phenanthroline was synthesized by doping different proportions of phenanthroline copper complexes in Schiff base. The morphology and structure of the products were investigated by scanning elec-tron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FT-IR), and the electrochemical performance of the electrode materials [Cu(Phen)Cl2]X-OTTP were analyzed by cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), and electrochemical impedance spectrum (EIS). The results exhibited that the morphology of the polymer Schiff base changed after doping with phenanthroline copper complexes. After doping, the Schiff base was scaly, with more holes on the surface and the layered structure was destroyed. The matrix π-π stacking was affected. In 6 mol·L-1 KOH electrolyte three-electrode system, [Cu(Phen)Cl2]0.4-OTTP had a high specific capacity of 278 mAh·g-1 at the current density of 0.5 A·g-1. The assembled supercapacitor [Cu(Phen)Cl2]0.4-OTTP//AC (AC=activated carbon) had a power density of 276.99 W·kg-1 at the energy density of 26.16 Wh·kg-1, and kept original specific capacity of 97.13% after 10 000 GCD cycles at current density of 10 A·g-1.
2023, 39(3): 406-414
doi: 10.11862/CJIC.2023.021
Abstract:
In this work, various Bi-based photocatalysts were prepared via a facile calcination process by using BiOIO3 as precursor. The microstructure, phase composition, and optical properties of these samples have been systematically studied by a series of characterization techniques. The photoactivities of these as-prepared samples were evaluated by the photodegradation of endocrine disruptor bisphenol A (BPA) under visible light (λ>420 nm) irradiation. The results showed that after calcination at 450 ℃ in air, BiOIO3 was completely changed into Bi5O7I nanosheets, and the degradation efficiency for BPA could reach 99.3% within 60 min. Meanwhile, after 5 photodegradation cycles, the degradation rate of BPA by Bi5O7I could still reach 97%, exhibiting remarkable reusability. However, Bi5O7I exhibited a wide band gap and could only absorb a small part of visible light. The surface interaction between BPA and Bi5O7I might be responsible for its visible light reactivity. To investigate the photocatalytic mechanism, UV‐Vis diffuse reflectance spectra (UV‐Vis DRS), X-ray photoelectron spectroscopy (XPS), and electrochemical experiments were performed on Bi5O7I before and after BPA adsorption. UV‐Vis DRS showed that Bi5O7I displayed enhanced absorption in the visible light region after modified by BPA. The intensive visible light harvesting property of Bi5O7I might be caused by ligand-to-metal charge transfer (LMCT) mechanism. XPS results confirmed the existence of a strong interaction between BPA and Bi5O7I, which might ascribe to surface complexation of BPA on Bi5O7I. Besides, the modification of Bi5O7I by BPA facilitated the migration and separation of photo-generated electron (e-) and hole (h+). Quenching experiments revealed that superoxide radical (·O2-), h+ and hydroxyl radical (·OH) were all participated in the photocatalytic reaction system. Combined with characterizations and experimental data, the mechanism of enhanced photodegradation performance through LMCT photosensitization mechanism between Bi5O7I and BPA was proposed.
In this work, various Bi-based photocatalysts were prepared via a facile calcination process by using BiOIO3 as precursor. The microstructure, phase composition, and optical properties of these samples have been systematically studied by a series of characterization techniques. The photoactivities of these as-prepared samples were evaluated by the photodegradation of endocrine disruptor bisphenol A (BPA) under visible light (λ>420 nm) irradiation. The results showed that after calcination at 450 ℃ in air, BiOIO3 was completely changed into Bi5O7I nanosheets, and the degradation efficiency for BPA could reach 99.3% within 60 min. Meanwhile, after 5 photodegradation cycles, the degradation rate of BPA by Bi5O7I could still reach 97%, exhibiting remarkable reusability. However, Bi5O7I exhibited a wide band gap and could only absorb a small part of visible light. The surface interaction between BPA and Bi5O7I might be responsible for its visible light reactivity. To investigate the photocatalytic mechanism, UV‐Vis diffuse reflectance spectra (UV‐Vis DRS), X-ray photoelectron spectroscopy (XPS), and electrochemical experiments were performed on Bi5O7I before and after BPA adsorption. UV‐Vis DRS showed that Bi5O7I displayed enhanced absorption in the visible light region after modified by BPA. The intensive visible light harvesting property of Bi5O7I might be caused by ligand-to-metal charge transfer (LMCT) mechanism. XPS results confirmed the existence of a strong interaction between BPA and Bi5O7I, which might ascribe to surface complexation of BPA on Bi5O7I. Besides, the modification of Bi5O7I by BPA facilitated the migration and separation of photo-generated electron (e-) and hole (h+). Quenching experiments revealed that superoxide radical (·O2-), h+ and hydroxyl radical (·OH) were all participated in the photocatalytic reaction system. Combined with characterizations and experimental data, the mechanism of enhanced photodegradation performance through LMCT photosensitization mechanism between Bi5O7I and BPA was proposed.
2023, 39(3): 415-421
doi: 10.11862/CJIC.2023.016
Abstract:
A series of Ca8MgBi(PO4)7∶Ce3+, Tb3+ phosphors with whitlockite-type structure and adjustable color were prepared by the high-temperature solid-phase method. The phase composition, microstructure, and luminescence properties were studied by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and fluorescence spectroscopy. X-ray diffraction results confirmed doping a small amount of Ce3+ and Tb3+ did not change the crystal structure of the matrix. The energy transfer between Ce3+-Tb3+ was confirmed by the fluorescence spectrum and fluorescence lifetime curve. The energy transfer mechanism was quadrupole-quadrupole interaction, and the energy transfer efficiency could reach 81%. The emission color of the series Ca8MgBi(PO4)7∶0.08Ce3+, yTb3+ phosphors can be adjusted from blue light to green light by changing the doping concentrations of Tb3+, realizing the controllable emission color change.
A series of Ca8MgBi(PO4)7∶Ce3+, Tb3+ phosphors with whitlockite-type structure and adjustable color were prepared by the high-temperature solid-phase method. The phase composition, microstructure, and luminescence properties were studied by X-ray powder diffraction (XRD), scanning electron microscope (SEM), and fluorescence spectroscopy. X-ray diffraction results confirmed doping a small amount of Ce3+ and Tb3+ did not change the crystal structure of the matrix. The energy transfer between Ce3+-Tb3+ was confirmed by the fluorescence spectrum and fluorescence lifetime curve. The energy transfer mechanism was quadrupole-quadrupole interaction, and the energy transfer efficiency could reach 81%. The emission color of the series Ca8MgBi(PO4)7∶0.08Ce3+, yTb3+ phosphors can be adjusted from blue light to green light by changing the doping concentrations of Tb3+, realizing the controllable emission color change.
2023, 39(3): 422-432
doi: 10.11862/CJIC.2022.284
Abstract:
Here, we report a three-dimensional blade -like nanosheet cobalt disulfide electrocatalyst with CoS2 as the main crystal phase with a small amount of the mixed NiO phase, which is fabricated in situ on nickel foam (NF) by one-step hydrothermal synthesis. When the molar ratio of cobalt and sulfur in the solution was 1∶5, the crystalline CoS2/NF electrocatalyst with a three-dimensional porous blade-like structure composed of 10 nm nanosheets was obtained at 140 ℃ for 18 h. During hybrid water electrolysis in an alkaline medium containing hydrazine hydrate, CoS2/NF electrode merely need 83 mV overpotential to deliver -10 mA·cm-2 towards hydrogen evolution reaction (HER), while 51 mV (vs RHE) oxidation potential to drive 50 mA·cm-2 towards hydrazine oxidation reaction (HzOR). Integrated into a hybrid cell towards hydrazine hydrate assisted water electrolysis, the CoS2/NF couple required a cell voltage of only 0.550 V to afford 100 mA·cm-2 current density, far lower than that of overall water splitting (2.075 V), giving rise to the significant decrease of power consumption and the great improvement of hydrogen-producing efficiency. As-prepared CoS2/NF displayed excellent stability and durability towards HER or HzOR both in three-electrode and two-electrode systems. The formation of a nanoporous blade-like structure created a large number of micropores on the electrode surface, which led to the nearly 24-fold increased electrochemical active area (ECSA), and provided a huge amount of active sites and material transfer channels for the catalytic reaction. The formation of cobalt disulfide and nickel oxide phase synergically improved the intrinsic hydrogen evolution activity to a certain extent. The composition and structural characteristics of CoS2/NF contribute to superior catalytic performance, and the structural advantage played the predominant role in outstanding catalytic performances. Using mechanism research, the reaction paths of CoS2/NF in HER and HzOR are proposed, respectively.
Here, we report a three-dimensional blade -like nanosheet cobalt disulfide electrocatalyst with CoS2 as the main crystal phase with a small amount of the mixed NiO phase, which is fabricated in situ on nickel foam (NF) by one-step hydrothermal synthesis. When the molar ratio of cobalt and sulfur in the solution was 1∶5, the crystalline CoS2/NF electrocatalyst with a three-dimensional porous blade-like structure composed of 10 nm nanosheets was obtained at 140 ℃ for 18 h. During hybrid water electrolysis in an alkaline medium containing hydrazine hydrate, CoS2/NF electrode merely need 83 mV overpotential to deliver -10 mA·cm-2 towards hydrogen evolution reaction (HER), while 51 mV (vs RHE) oxidation potential to drive 50 mA·cm-2 towards hydrazine oxidation reaction (HzOR). Integrated into a hybrid cell towards hydrazine hydrate assisted water electrolysis, the CoS2/NF couple required a cell voltage of only 0.550 V to afford 100 mA·cm-2 current density, far lower than that of overall water splitting (2.075 V), giving rise to the significant decrease of power consumption and the great improvement of hydrogen-producing efficiency. As-prepared CoS2/NF displayed excellent stability and durability towards HER or HzOR both in three-electrode and two-electrode systems. The formation of a nanoporous blade-like structure created a large number of micropores on the electrode surface, which led to the nearly 24-fold increased electrochemical active area (ECSA), and provided a huge amount of active sites and material transfer channels for the catalytic reaction. The formation of cobalt disulfide and nickel oxide phase synergically improved the intrinsic hydrogen evolution activity to a certain extent. The composition and structural characteristics of CoS2/NF contribute to superior catalytic performance, and the structural advantage played the predominant role in outstanding catalytic performances. Using mechanism research, the reaction paths of CoS2/NF in HER and HzOR are proposed, respectively.
2023, 39(3): 433-442
doi: 10.11862/CJIC.2023.022
Abstract:
Sb2O3/BiVO4/WO3 semiconductor heterojunctions were constructed by solvothermal method and spin coating method, and X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy were used to characterize the physical and chemical properties. The photocurrent density of BiVO4/WO3 was increased by two times compared with BiVO4 at 1.23 V (vs RHE). Although further coating with Sb2O3 decreased the photocurrent density of Sb2O3/BiVO4/WO3 film, the Faraday efficiency and production rate of H2O2 were improved. At 1.89 V (vs RHE), the Faraday efficiency of 3c‐Sb2O3/BiVO4/WO3 film was enhanced to ca. 19%; the production rate of H2O2 of 1c‐Sb2 O3/BiVO4 /WO3 film increased from ca. 2.1 to ca. 3.6 μmol·h-1·cm-2. In addition, the coating of Sb2O3 significantly improved the photoelectrocatalytic stability of BiVO4/WO3 electrode.
Sb2O3/BiVO4/WO3 semiconductor heterojunctions were constructed by solvothermal method and spin coating method, and X‐ray diffraction, scanning electron microscopy, and X‐ray photoelectron spectroscopy were used to characterize the physical and chemical properties. The photocurrent density of BiVO4/WO3 was increased by two times compared with BiVO4 at 1.23 V (vs RHE). Although further coating with Sb2O3 decreased the photocurrent density of Sb2O3/BiVO4/WO3 film, the Faraday efficiency and production rate of H2O2 were improved. At 1.89 V (vs RHE), the Faraday efficiency of 3c‐Sb2O3/BiVO4/WO3 film was enhanced to ca. 19%; the production rate of H2O2 of 1c‐Sb2 O3/BiVO4 /WO3 film increased from ca. 2.1 to ca. 3.6 μmol·h-1·cm-2. In addition, the coating of Sb2O3 significantly improved the photoelectrocatalytic stability of BiVO4/WO3 electrode.
2023, 39(3): 443-455
doi: 10.11862/CJIC.2022.286
Abstract:
The poor cycle stability and rate performance are the technical obstacles to realizing the commercialization of Li-S battery, and one of the main reasons is the slow electrochemical conversion rates of sulfur active species in the sulfur electrode. In this work, for improving the electrochemical conversion of polysulfides in sulfur electrodes, ZIF-9 derived N-doped porous carbon decorated with CoSe (CoSe/NC) was chosen and obtained through carbonization, acid pickling, and selenylation processes. The electrochemical kinetics of polysulfide conversion on CoSe/NC was studied using a flowing electrolyte three-electrode system. As a result, CoSe/NC composite took an effect on enhancing the reaction rates of polysulfide conversion. CoSe/NC composite gave more help to decrease the reaction overpotential under a current density of 0.2 mA·cm-2. Meanwhile, the high response currents would be obtained with the help of CoSe/NC composite under an overpotential of 0.1 V. Moreover, the redox reaction for Li2S2 on CoSe/NC composite had the largest increase in amplitude in exchange current density. Therefore, the batteries assembled with CoSe/NC composite as sulfur host displayed fantastic electrochemical performances. The initial discharge specific capacity was 1068 mAh·g-1 at 1C (1C=1675 mA·g-1) and the retentive capacity was as high as 693 mAh·g-1 after 500 cycles. In addition, the discharge specific capacity can be up to 819 mAh·g-1 even at a high current density of 3C.
The poor cycle stability and rate performance are the technical obstacles to realizing the commercialization of Li-S battery, and one of the main reasons is the slow electrochemical conversion rates of sulfur active species in the sulfur electrode. In this work, for improving the electrochemical conversion of polysulfides in sulfur electrodes, ZIF-9 derived N-doped porous carbon decorated with CoSe (CoSe/NC) was chosen and obtained through carbonization, acid pickling, and selenylation processes. The electrochemical kinetics of polysulfide conversion on CoSe/NC was studied using a flowing electrolyte three-electrode system. As a result, CoSe/NC composite took an effect on enhancing the reaction rates of polysulfide conversion. CoSe/NC composite gave more help to decrease the reaction overpotential under a current density of 0.2 mA·cm-2. Meanwhile, the high response currents would be obtained with the help of CoSe/NC composite under an overpotential of 0.1 V. Moreover, the redox reaction for Li2S2 on CoSe/NC composite had the largest increase in amplitude in exchange current density. Therefore, the batteries assembled with CoSe/NC composite as sulfur host displayed fantastic electrochemical performances. The initial discharge specific capacity was 1068 mAh·g-1 at 1C (1C=1675 mA·g-1) and the retentive capacity was as high as 693 mAh·g-1 after 500 cycles. In addition, the discharge specific capacity can be up to 819 mAh·g-1 even at a high current density of 3C.
2023, 39(3): 456-464
doi: 10.11862/CJIC.2022.287
Abstract:
Nanocellulose/reduced graphene oxide (NC/rGO) composites were prepared by a simple one-step hydrothermal method using high-concentration graphene oxide (GO) solution as the reaction precursor and nanocellulose (NC) as the physical spacer and electrolyte reservoirs. Subsequently, we explored the potential of NC/rGO as electrode materials for supercapacitors. Due to its dense porous structure and large oxygen-containing functional group content, NC/rGO-1 prepared with 1 mL NC exhibited the best electrochemical performance. The binder-free symmetric supercapacitor based on NC/rGO-1 showed high gravimetric and volumetric specific capacitance of 269.33 F·g-1 and 350.13 F·cm-3 at a current density of 0.3 A·g-1. These values can still reach 215.88 F·g-1 and 280.62 F·cm-3 at 10.0 A·g-1 (80.15% of its initial value). The assembled device also displayed high gravimetric and volumetric energy densities (9.3 Wh·kg-1 and 12.13 Wh·L-1) and excellent cycling performance (the initial specific capacitance decreased by only 6.02% after 10 000 cycles at 10 A·g-1).
Nanocellulose/reduced graphene oxide (NC/rGO) composites were prepared by a simple one-step hydrothermal method using high-concentration graphene oxide (GO) solution as the reaction precursor and nanocellulose (NC) as the physical spacer and electrolyte reservoirs. Subsequently, we explored the potential of NC/rGO as electrode materials for supercapacitors. Due to its dense porous structure and large oxygen-containing functional group content, NC/rGO-1 prepared with 1 mL NC exhibited the best electrochemical performance. The binder-free symmetric supercapacitor based on NC/rGO-1 showed high gravimetric and volumetric specific capacitance of 269.33 F·g-1 and 350.13 F·cm-3 at a current density of 0.3 A·g-1. These values can still reach 215.88 F·g-1 and 280.62 F·cm-3 at 10.0 A·g-1 (80.15% of its initial value). The assembled device also displayed high gravimetric and volumetric energy densities (9.3 Wh·kg-1 and 12.13 Wh·L-1) and excellent cycling performance (the initial specific capacitance decreased by only 6.02% after 10 000 cycles at 10 A·g-1).
2023, 39(3): 465-474
doi: 10.11862/CJIC.2023.015
Abstract:
X-ray diffraction, Fourier transform infrared spectrometer, scanning electron microscope, ζ potential analyzer, and inductively coupled plasma emission spectrometer were used to compare the regulation of four degraded seaweed polysaccharides with a similar molecular weight of about 3700 Da and different contents of sulfate group (—OSO3-) on the inhibition of crystal growth of calcium oxalate (CaC2O4), and the repair ability of the polysaccharides on damaged renal epithelial cells was compared by cell experiments. These four seaweed polysaccharides were degraded Porphyra polysaccharide (PY-1), degraded Gracilaria lemaneiformis polysaccharide (GL-2), degraded Sargassum fusiforme polysaccharide (SF-3) and degraded Undaria pinnatifida polysaccharide (UP-4), and their —OSO3- contents were 17.9%, 13.3%, 8.2%, and 5.5%, respectively. The results showed that these four polysaccharides could inhibit the growth of calcium oxalate monohydrate (COM), induce the formation of calcium oxalate dihydrate (COD), increase the concentration of soluble Ca2+ ions in solution, and increase the absolute value of ζ potential on the crystal surface, thereby reducing the degree of crystal aggregation. In addition, these polysaccharides could repair HK-2 cells damaged by oxalic acid, increase cell viability and superoxide dismutase (SOD) activity, and reduce the release of malondialdehyde (MDA). The results show that the higher the content of —OSO3- in polysaccharides, the stronger the inhibitory effect of polysaccharides on CaC2O4 crystal growth and the repair effect on damaged HK-2 cells.
X-ray diffraction, Fourier transform infrared spectrometer, scanning electron microscope, ζ potential analyzer, and inductively coupled plasma emission spectrometer were used to compare the regulation of four degraded seaweed polysaccharides with a similar molecular weight of about 3700 Da and different contents of sulfate group (—OSO3-) on the inhibition of crystal growth of calcium oxalate (CaC2O4), and the repair ability of the polysaccharides on damaged renal epithelial cells was compared by cell experiments. These four seaweed polysaccharides were degraded Porphyra polysaccharide (PY-1), degraded Gracilaria lemaneiformis polysaccharide (GL-2), degraded Sargassum fusiforme polysaccharide (SF-3) and degraded Undaria pinnatifida polysaccharide (UP-4), and their —OSO3- contents were 17.9%, 13.3%, 8.2%, and 5.5%, respectively. The results showed that these four polysaccharides could inhibit the growth of calcium oxalate monohydrate (COM), induce the formation of calcium oxalate dihydrate (COD), increase the concentration of soluble Ca2+ ions in solution, and increase the absolute value of ζ potential on the crystal surface, thereby reducing the degree of crystal aggregation. In addition, these polysaccharides could repair HK-2 cells damaged by oxalic acid, increase cell viability and superoxide dismutase (SOD) activity, and reduce the release of malondialdehyde (MDA). The results show that the higher the content of —OSO3- in polysaccharides, the stronger the inhibitory effect of polysaccharides on CaC2O4 crystal growth and the repair effect on damaged HK-2 cells.
2023, 39(3): 475-484
doi: 10.11862/CJIC.2023.013
Abstract:
Rubik's cube-like nano-microstructure BaTiO 3 was synthesized via a simple solvothermal method by changing the molar ratio of Ba to Ti, and its piezocatalytic performance was characterized by degrading 5 mg·L-1 rhodamine B (RhB) solution. The morphology and phase structure of as-synthesized samples were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectra (FT-IR). The piezo-catalytic performance of synthesized BaTiO3 was investigated. The results exhibited that as-synthesized samples presented a Rubik's cube-like tetragonal BaTiO3 which assembled from cubes when the molar ratio of Ba to Ti was 1∶1. Under the condition of ultrasonic frequency of 40 kHz and ultrasonic power of 360 W, the degradation rate reached 90% at 180 min, the degradation rate was 79.7%, and changed to 11.4% after five cycles, which is superior to photocatalytic performance. During the degradation process, as-synthesized Rubik's cube-like BaTiO3 showed more excellent piezocatalytic performance with better piezocatalytic activity and durability than photocatalytic.
Rubik's cube-like nano-microstructure BaTiO 3 was synthesized via a simple solvothermal method by changing the molar ratio of Ba to Ti, and its piezocatalytic performance was characterized by degrading 5 mg·L-1 rhodamine B (RhB) solution. The morphology and phase structure of as-synthesized samples were analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared spectra (FT-IR). The piezo-catalytic performance of synthesized BaTiO3 was investigated. The results exhibited that as-synthesized samples presented a Rubik's cube-like tetragonal BaTiO3 which assembled from cubes when the molar ratio of Ba to Ti was 1∶1. Under the condition of ultrasonic frequency of 40 kHz and ultrasonic power of 360 W, the degradation rate reached 90% at 180 min, the degradation rate was 79.7%, and changed to 11.4% after five cycles, which is superior to photocatalytic performance. During the degradation process, as-synthesized Rubik's cube-like BaTiO3 showed more excellent piezocatalytic performance with better piezocatalytic activity and durability than photocatalytic.
2023, 39(3): 485-491
doi: 10.11862/CJIC.2023.014
Abstract:
The effects of B2O3-Bi2O3-ZnO-Al2O3 (BBZA) glass on the sintering conditions, crystal structure, and dielectric properties of barium titanate (BaTiO 3) ceramics were investigated. The results show that the addition of the appropriate amount of BBZA glass powder can effectively reduce the sintering temperature of BaTiO3 ceramics from 1 350 to 950 ℃ and make it densified. Consequently, the structure of BaTiO3 phase changed (cubic phase → tetragonal phase) with the increase of sintering temperature after adding BBZA glass. Additionally, the Curie peak of BaTiO3 ceramics were effectively suppressed and broadened. The ceramic microstructure showed that the glass phase was uniformly distributed on the surface of BaTiO3 grains. The optimized preparing conditions for the BaTiO3 ceramics were as follows: the addition (mass fraction) of BBZA glass was 2.0% and the sintering temperature was 950 ℃. The BaTiO3 ceramics prepared under these conditions had a dielectric constant of 1 364 and a dielectric loss as low as 1.2%. When the sintering temperature was higher than 950℃, the addition amount of BBZA glass should not be greater than 2.0%, too much BBZA glass will lead to the semiconducting of BaTiO3.
The effects of B2O3-Bi2O3-ZnO-Al2O3 (BBZA) glass on the sintering conditions, crystal structure, and dielectric properties of barium titanate (BaTiO 3) ceramics were investigated. The results show that the addition of the appropriate amount of BBZA glass powder can effectively reduce the sintering temperature of BaTiO3 ceramics from 1 350 to 950 ℃ and make it densified. Consequently, the structure of BaTiO3 phase changed (cubic phase → tetragonal phase) with the increase of sintering temperature after adding BBZA glass. Additionally, the Curie peak of BaTiO3 ceramics were effectively suppressed and broadened. The ceramic microstructure showed that the glass phase was uniformly distributed on the surface of BaTiO3 grains. The optimized preparing conditions for the BaTiO3 ceramics were as follows: the addition (mass fraction) of BBZA glass was 2.0% and the sintering temperature was 950 ℃. The BaTiO3 ceramics prepared under these conditions had a dielectric constant of 1 364 and a dielectric loss as low as 1.2%. When the sintering temperature was higher than 950℃, the addition amount of BBZA glass should not be greater than 2.0%, too much BBZA glass will lead to the semiconducting of BaTiO3.
2023, 39(3): 492-500
doi: 10.11862/CJIC.2023.019
Abstract:
Nitrogen-containing mesoporous carbon with different specific surface areas and pore volumes were prepared by using colloidal silica spheres as the hard template, chitosan as a carbon precursor, and ZnCl2 as activation agent. The morphology, surface area, and pore structure of the prepared carbons were characterized by different techniques. The influence of the ratio of silica to chitosan and the use of ZnCl2 on the pore volume and surface area of porous carbon materials were explored. It was found that the nitrogen-doped mesoporous carbon (CSi-1.75) without using activation agent showed lowest surface area but the pore volume can reach up to 4.53 cm3·g-1. The carbon (CSi-1.75-Zn) prepared by using ZnCl2 as activation agent, had the larger surface area (1 032 m2·g -1) and the pore volume decreased to 1.99 cm3·g-1 and had more pyridine-nitrogen and pyrrole-nitrogen. In the three electrodes with 6.0 mol·L-1 KOH as the electrolyte, when the current density was 0.5 A·g-1, the specific capacitance of CSi-1.75-Zn can reach 344 F·g -1, while the specific capacitance of CSi-1.75 was only 255 F·g-1. This indicates that the surface area of the carbon material had the greatest impact on the supercapacitive performance. The capacitance contribution analysis results showed that both the double-layer capacitance and pseudo capacitance of CSi-1.75-Zn were improved compared with CSi-1.75, indicating that larger specific surface area and more pyridine-nitrogen and pyrrole-nitrogen are conducive to improving the capacitance of carbon materials.
Nitrogen-containing mesoporous carbon with different specific surface areas and pore volumes were prepared by using colloidal silica spheres as the hard template, chitosan as a carbon precursor, and ZnCl2 as activation agent. The morphology, surface area, and pore structure of the prepared carbons were characterized by different techniques. The influence of the ratio of silica to chitosan and the use of ZnCl2 on the pore volume and surface area of porous carbon materials were explored. It was found that the nitrogen-doped mesoporous carbon (CSi-1.75) without using activation agent showed lowest surface area but the pore volume can reach up to 4.53 cm3·g-1. The carbon (CSi-1.75-Zn) prepared by using ZnCl2 as activation agent, had the larger surface area (1 032 m2·g -1) and the pore volume decreased to 1.99 cm3·g-1 and had more pyridine-nitrogen and pyrrole-nitrogen. In the three electrodes with 6.0 mol·L-1 KOH as the electrolyte, when the current density was 0.5 A·g-1, the specific capacitance of CSi-1.75-Zn can reach 344 F·g -1, while the specific capacitance of CSi-1.75 was only 255 F·g-1. This indicates that the surface area of the carbon material had the greatest impact on the supercapacitive performance. The capacitance contribution analysis results showed that both the double-layer capacitance and pseudo capacitance of CSi-1.75-Zn were improved compared with CSi-1.75, indicating that larger specific surface area and more pyridine-nitrogen and pyrrole-nitrogen are conducive to improving the capacitance of carbon materials.
2023, 39(3): 501-509
doi: 10.11862/CJIC.2023.008
Abstract:
A series of quasi-2D perovskites with both electroluminescence and optical gain properties were designed and synthesized in this work. The 4-FPEA+ (4-FPEAB=4-fluorophenylethylamine hydrobromide) was introduced into CsPbBr3 to prepared quasi-2D perovskites thin films with different n-value quantum wells distribution by using simple solution coating method. The UV-Vis absorption and photoluminescence spectra were adopted to suggest that quantum wells distribution can be modulated effectively by controlling the proportion of precursors in solution precisely. These samples were characterized by scanning electron microscopy and atomic force microscopy. The result suggested that 4-FPEA+ can reduce surface roughness efficiently. When the molar ratio of 4-FPEA+ and CsPbBr3 reached 0.6, as-prepared perovskite films were demonstrated with the highest brightness. Using additive defect passivation strategy with crown ether, more uniform quantum well distribution achieved which further promoted the efficient energy transfer. The light emitting diodes (LED) devices realized the external quantum efficiencies (EQE) as 0.98%. In terms of laser performance, amplified spontaneous emissions (ASEs) with a low threshold of 17.42 μJ· cm-2 and gain coefficients as 35 cm-1 in room temperature were realized.
A series of quasi-2D perovskites with both electroluminescence and optical gain properties were designed and synthesized in this work. The 4-FPEA+ (4-FPEAB=4-fluorophenylethylamine hydrobromide) was introduced into CsPbBr3 to prepared quasi-2D perovskites thin films with different n-value quantum wells distribution by using simple solution coating method. The UV-Vis absorption and photoluminescence spectra were adopted to suggest that quantum wells distribution can be modulated effectively by controlling the proportion of precursors in solution precisely. These samples were characterized by scanning electron microscopy and atomic force microscopy. The result suggested that 4-FPEA+ can reduce surface roughness efficiently. When the molar ratio of 4-FPEA+ and CsPbBr3 reached 0.6, as-prepared perovskite films were demonstrated with the highest brightness. Using additive defect passivation strategy with crown ether, more uniform quantum well distribution achieved which further promoted the efficient energy transfer. The light emitting diodes (LED) devices realized the external quantum efficiencies (EQE) as 0.98%. In terms of laser performance, amplified spontaneous emissions (ASEs) with a low threshold of 17.42 μJ· cm-2 and gain coefficients as 35 cm-1 in room temperature were realized.
2023, 39(3): 510-520
doi: 10.11862/CJIC.2023.017
Abstract:
A novel and interesting Yb8 cluster, namely [Yb8(acac)4(HL)4(L)2(μ3-O)4(C2H5O)4]·2C2H5OH·2CH2Cl2 (1) (H2L=2-hydroxy-benzoic acid (5-hydroxymethyl-furan-2-ylmethylene)-hydrazide, and Hacac=acetylacetone), has been constructed by using a polydentate Schiff base ligand (H2L). X-ray diffraction analysis indicates that cluster 1 shows a central symmetric octanuclear structure. The eight-coordinated Yb1(Ⅲ) ion possesses a distorted bi-augmented trigonal prism geometrical configuration; while the three seven-coordinated Yb(Ⅲ) ions (Yb2, Yb3, and Yb4) possess capped trigonal prism, pentagonal bipyramid, and capped octahedron geometrical configuration, respectively. Cluster 1 possesses excellent solvent stability. Moreover, the photoluminescence property study shows that 1 displayed typical near-infrared luminescence of Yb(Ⅲ) at room temperature. Interestingly, cluster 1 exhibited high catalytic activity and can effectively catalyze the cycloaddition reaction of CO2 with various epoxides. As a heterogeneous catalyst, cluster 1 showed good cycling performance.
A novel and interesting Yb8 cluster, namely [Yb8(acac)4(HL)4(L)2(μ3-O)4(C2H5O)4]·2C2H5OH·2CH2Cl2 (1) (H2L=2-hydroxy-benzoic acid (5-hydroxymethyl-furan-2-ylmethylene)-hydrazide, and Hacac=acetylacetone), has been constructed by using a polydentate Schiff base ligand (H2L). X-ray diffraction analysis indicates that cluster 1 shows a central symmetric octanuclear structure. The eight-coordinated Yb1(Ⅲ) ion possesses a distorted bi-augmented trigonal prism geometrical configuration; while the three seven-coordinated Yb(Ⅲ) ions (Yb2, Yb3, and Yb4) possess capped trigonal prism, pentagonal bipyramid, and capped octahedron geometrical configuration, respectively. Cluster 1 possesses excellent solvent stability. Moreover, the photoluminescence property study shows that 1 displayed typical near-infrared luminescence of Yb(Ⅲ) at room temperature. Interestingly, cluster 1 exhibited high catalytic activity and can effectively catalyze the cycloaddition reaction of CO2 with various epoxides. As a heterogeneous catalyst, cluster 1 showed good cycling performance.
2023, 39(3): 521-532
doi: 10.11862/CJIC.2023.010
Abstract:
The anhydrous lactate complex (NH4)2[Sr(C3H5O3)4] was synthesized. The crystal structure was characterized by an X-ray single crystal diffractometer, and its composition, spatial structure, and coordination mode were determined. The Hirshfeld surface and 2D fingerprint plot of the complex were drawn, which provided reliable support for revealing the intermolecular interaction and revealed that the complex has many coordination sites and strong coordination activity. The crystal data were used to calculate the complex's lattice energy and its common anion's molar volume. The lattice energy of the complex was calculated to be 2742.9 kJ·mol-1. The enthalpy of dissolution of the complex in ultra-pure water as solvent at 298 K was measured by an isoperibol solution-reaction calorimeter. According to Pitzer's electrolyte solution theory, the infinite dilution molar dissolution enthalpy and Pitzer's parameters of the complex were obtained at 298 K. The complex's infinite dilution molar enthalpy of dissolution (ΔsHm∞) was determined to be (114.01±0.04) kJ·mol-1. The apparent relative molar enthalpy ΦL of the complex and the relative partial molar enthalpies (L1 and L2) of solute and solvent at different concentrations were calculated. Finally, the thermochemical cycle was designed according to the lattice potential energy and the infinite dilution molar dissolution enthalpy of the complex, and the hydration enthalpies of the complex and its D/L-lactate ion were calculated. Thermogravimetry and derivative thermogravimetry curves further revealed the structure of the complex. CCDC: 2099796.
The anhydrous lactate complex (NH4)2[Sr(C3H5O3)4] was synthesized. The crystal structure was characterized by an X-ray single crystal diffractometer, and its composition, spatial structure, and coordination mode were determined. The Hirshfeld surface and 2D fingerprint plot of the complex were drawn, which provided reliable support for revealing the intermolecular interaction and revealed that the complex has many coordination sites and strong coordination activity. The crystal data were used to calculate the complex's lattice energy and its common anion's molar volume. The lattice energy of the complex was calculated to be 2742.9 kJ·mol-1. The enthalpy of dissolution of the complex in ultra-pure water as solvent at 298 K was measured by an isoperibol solution-reaction calorimeter. According to Pitzer's electrolyte solution theory, the infinite dilution molar dissolution enthalpy and Pitzer's parameters of the complex were obtained at 298 K. The complex's infinite dilution molar enthalpy of dissolution (ΔsHm∞) was determined to be (114.01±0.04) kJ·mol-1. The apparent relative molar enthalpy ΦL of the complex and the relative partial molar enthalpies (L1 and L2) of solute and solvent at different concentrations were calculated. Finally, the thermochemical cycle was designed according to the lattice potential energy and the infinite dilution molar dissolution enthalpy of the complex, and the hydration enthalpies of the complex and its D/L-lactate ion were calculated. Thermogravimetry and derivative thermogravimetry curves further revealed the structure of the complex. CCDC: 2099796.
2023, 39(3): 533-544
doi: 10.11862/CJIC.2023.007
Abstract:
The Vis-NIR light-responsive direct Z-scheme LaNiO3/CdS nanohybrid was synthesized via a refluxing method, fully characterized, and used in photocatalytic H2 evolution. The H2 evolved over LaNiO3/CdS photocatalyst in 5 h was 737 μmol under visible light irradiation, which was 4.3 times that over CdS (172 μmol) ascribed to the formed heterojunction between LaNiO3 and CdS. Moreover, the introduced LaNiO3 extended the light absorption to the NIR region and the H2 evolution increased to 996 μmol under Vis-NIR light irradiation. LaNiO3 exhibited upconversion luminescence at 406 and 628 nm when excited at 808 nm, which means that LaNiO3 can generate charge carriers under NIR light irradiation, thereby further improving the efficiency of its photocatalytic H2 evolution.
The Vis-NIR light-responsive direct Z-scheme LaNiO3/CdS nanohybrid was synthesized via a refluxing method, fully characterized, and used in photocatalytic H2 evolution. The H2 evolved over LaNiO3/CdS photocatalyst in 5 h was 737 μmol under visible light irradiation, which was 4.3 times that over CdS (172 μmol) ascribed to the formed heterojunction between LaNiO3 and CdS. Moreover, the introduced LaNiO3 extended the light absorption to the NIR region and the H2 evolution increased to 996 μmol under Vis-NIR light irradiation. LaNiO3 exhibited upconversion luminescence at 406 and 628 nm when excited at 808 nm, which means that LaNiO3 can generate charge carriers under NIR light irradiation, thereby further improving the efficiency of its photocatalytic H2 evolution.
2023, 39(3): 545-553
doi: 10.11862/CJIC.2023.020
Abstract:
Two new coordination polymers [Co(L)0.5(1, 4-bib)(H2O)3]n (1) and [Ni(L)0.5(1, 4-bib)(H2O)3]n (2) (H4L=1, 4-bis (2, 6-dimethyl-3, 5-dicarboxypyridyl) benzene, 1, 4-bib=1, 4-bis(1-imidazolyl) benzene) were synthesized by hydrothermal method. Their structures were characterized by single crystal and powder X-ray diffraction, elemental analysis, infrared spectroscopic analysis, and thermogravimetric analysis. Structural analysis shows that complexes 1 and 2 are heterogeneous isomorphisms and 1D structures. The antiferromagnetic interaction between Co(Ⅱ)/Ni(Ⅱ) ions in complexes 1 and 2 was found by variable temperature magnetic susceptibility measurement. In addition, complex 1 can be used to detect cefixime (CEF) by fluorescence quenching method, and complex 2 can be used to detect tetra-cycline (TET). This method had high sensitivity and good selectivity, and their detection limits were 0.86 μmol·L-1 (CEF) and 0.49 μmol·L-1 (TET), respectively.
Two new coordination polymers [Co(L)0.5(1, 4-bib)(H2O)3]n (1) and [Ni(L)0.5(1, 4-bib)(H2O)3]n (2) (H4L=1, 4-bis (2, 6-dimethyl-3, 5-dicarboxypyridyl) benzene, 1, 4-bib=1, 4-bis(1-imidazolyl) benzene) were synthesized by hydrothermal method. Their structures were characterized by single crystal and powder X-ray diffraction, elemental analysis, infrared spectroscopic analysis, and thermogravimetric analysis. Structural analysis shows that complexes 1 and 2 are heterogeneous isomorphisms and 1D structures. The antiferromagnetic interaction between Co(Ⅱ)/Ni(Ⅱ) ions in complexes 1 and 2 was found by variable temperature magnetic susceptibility measurement. In addition, complex 1 can be used to detect cefixime (CEF) by fluorescence quenching method, and complex 2 can be used to detect tetra-cycline (TET). This method had high sensitivity and good selectivity, and their detection limits were 0.86 μmol·L-1 (CEF) and 0.49 μmol·L-1 (TET), respectively.
2023, 39(3): 554-562
doi: 10.11862/CJIC.2023.024
Abstract:
Three cobalt(Ⅱ)), copper(Ⅱ), and cadmium(Ⅱ) coordination polymers, namely [Co2(μ4-dia)(phen)2(H2O)2]n (1), [Cu2(μ6-dia)(bipy)2]n (2), and {[Cd2(μ5-dia)(μ-bpa)2(H2O)]·H2O}n (3) have been constructed hydrothermally using H4dia (5-(2, 5-dicarboxyphenoxy)isophthalic acid), phen (phen=1, 10-phenanthroline), bipy (2, 2'-bipyridine), bpa (bis(4-pyridyl)amine), and cobalt, copper and cadmium chlorides at 160 ℃. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses, and singlecrystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses reveal that three compounds crystallize in the monoclinic or triclinic systems, space groups P21/n, P21/c, or P1. Compound 1 discloses a 1D double-chain structure. Compounds 2 and 3 show 3D frameworks. The catalytic activity in the Knoevenagel condensation reaction of these compounds was investigated. Compound 2 exhibited excellent catalytic activity in the Knoevenagel conden-sation reaction at 50 ℃.
Three cobalt(Ⅱ)), copper(Ⅱ), and cadmium(Ⅱ) coordination polymers, namely [Co2(μ4-dia)(phen)2(H2O)2]n (1), [Cu2(μ6-dia)(bipy)2]n (2), and {[Cd2(μ5-dia)(μ-bpa)2(H2O)]·H2O}n (3) have been constructed hydrothermally using H4dia (5-(2, 5-dicarboxyphenoxy)isophthalic acid), phen (phen=1, 10-phenanthroline), bipy (2, 2'-bipyridine), bpa (bis(4-pyridyl)amine), and cobalt, copper and cadmium chlorides at 160 ℃. The products were isolated as stable crystalline solids and were characterized by IR spectra, elemental analyses, thermogravimetric analyses, and singlecrystal X-ray diffraction analyses. Single-crystal X-ray diffraction analyses reveal that three compounds crystallize in the monoclinic or triclinic systems, space groups P21/n, P21/c, or P1. Compound 1 discloses a 1D double-chain structure. Compounds 2 and 3 show 3D frameworks. The catalytic activity in the Knoevenagel condensation reaction of these compounds was investigated. Compound 2 exhibited excellent catalytic activity in the Knoevenagel conden-sation reaction at 50 ℃.
2023, 39(3): 563-574
doi: 10.11862/CJIC.2023.011
Abstract:
Herein, hydrothermally treated red phosphorus (HRP) was combined with bismuth bromide oxide (BiOBr) to construct BiOBr/HRP heterostructure composite. Regulating and optimizing the composition ratio, 7%BiOBr/HRP (The mass fraction of BiOBr in the composite was 7%) exhibited the highest photocatalytic activity, the rate constant for visible light reduction of Cr(Ⅵ) was 0.188 min-1, which was five times higher than that of pure HRP (0.037 6 min-1). The heterojunction composite constructed by introducing wide band gap BiOBr into narrow band gap HRP expanded the visible spectral absorption range, enhanced the light absorption, and accelerated the separation of photo-generated electrons and holes.
Herein, hydrothermally treated red phosphorus (HRP) was combined with bismuth bromide oxide (BiOBr) to construct BiOBr/HRP heterostructure composite. Regulating and optimizing the composition ratio, 7%BiOBr/HRP (The mass fraction of BiOBr in the composite was 7%) exhibited the highest photocatalytic activity, the rate constant for visible light reduction of Cr(Ⅵ) was 0.188 min-1, which was five times higher than that of pure HRP (0.037 6 min-1). The heterojunction composite constructed by introducing wide band gap BiOBr into narrow band gap HRP expanded the visible spectral absorption range, enhanced the light absorption, and accelerated the separation of photo-generated electrons and holes.
2023, 39(3): 575-584
doi: 10.11862/CJIC.2023.025
Abstract:
Activated magnetic porous carbon microspheres (A‐Fe3O4/C) based on chitosan (CS) were prepared using a two‐step synthesis method. The prepared A‐Fe3O4/C was employed as an adsorbent to remove the methylene blue (MB) from water. First, magnetic microspheres Fe3O4/CS were prepared through electrostatic spraying with CS and FeCl2/FeCl3 as the precursor. Subsequently, Fe3O4/CS was converted into A‐Fe3O4/C using a combination method of high‐temperature carbonization and alkali activation. The obtained magnetic microspheres were systematically characterized by scanning electron microscopy, Fourier transform infrared, and specific surface area analyzer, and several major factors of the adsorption‐based removal were studied (e.g., pH of the solution, adsorbent dosage, temperature, contact time, as well as alkali activator). The removal efficiency was significantly dependent on the pH of the solution, and high pH values facilitated the removal of MB from water. The adsorption to MB was consistent with the pseudo ‐ second ‐ order kinetic equation, and the adsorption process was expressed using the Langmuir isotherm model. The maximum adsorption capacity of MB was examined as 300.6 mg·g-1. Notably, the synthesized adsorbent could be effectively regenerated and repeatedly used without significant capacity loss after six cycles.
Activated magnetic porous carbon microspheres (A‐Fe3O4/C) based on chitosan (CS) were prepared using a two‐step synthesis method. The prepared A‐Fe3O4/C was employed as an adsorbent to remove the methylene blue (MB) from water. First, magnetic microspheres Fe3O4/CS were prepared through electrostatic spraying with CS and FeCl2/FeCl3 as the precursor. Subsequently, Fe3O4/CS was converted into A‐Fe3O4/C using a combination method of high‐temperature carbonization and alkali activation. The obtained magnetic microspheres were systematically characterized by scanning electron microscopy, Fourier transform infrared, and specific surface area analyzer, and several major factors of the adsorption‐based removal were studied (e.g., pH of the solution, adsorbent dosage, temperature, contact time, as well as alkali activator). The removal efficiency was significantly dependent on the pH of the solution, and high pH values facilitated the removal of MB from water. The adsorption to MB was consistent with the pseudo ‐ second ‐ order kinetic equation, and the adsorption process was expressed using the Langmuir isotherm model. The maximum adsorption capacity of MB was examined as 300.6 mg·g-1. Notably, the synthesized adsorbent could be effectively regenerated and repeatedly used without significant capacity loss after six cycles.
