Well-developed Porous Structure Research Articles

Effect of Surface Area, Particle Size and Acid Washing on the Quality of Activated Carbon Derived from Lower Rank Coal by KOH Activation

The use of coal-derived activated carbon (AC) for water treatment applications demands more sustainable production methods, with chemical activation emerging as a promising alternative to thermal activation due to its higher AC quality, lower carbon burn-off, and higher yield. The study explored the effect of surface area, particle size and acid washing on the quality of AC derived from three seams of lower-rank Collie coal under the same activation conditions with potassium hydroxide (KOH). The quality of AC was determined by surface area and iodine number. The study demonstrates that Collie coal, suitable for AC production via KOH activation, yielded iodine numbers of 640 and 900 mg/g, with yields of 53 and 57 wt.%. Particle size influenced AC yield, with finer particle sizes yielding AC at 57–59 wt.%, whereas coarser ones yielded around 58–65 wt.%. SEM analysis shows the well-developed porous structure in Collie coal-derived activated carbons, with cleaner particles after acid washing. A positive correlation exists between coal surface area and AC iodine numbers, with higher values in coal samples correlating to increased iodine numbers in resulting AC. The regression model’s predicted values yield a coefficient of determination (R²) of 0.99.

Oxygen-vacancies-rich TinO2n-1 quantum dots embedded Ti3CNTx/CNTs foam by HCl induced self-assembly and spontaneous oxidation towards strong and multiband microwave absorption

Ti3CNTx/TinO2n-1 foam and Ti3CNTx/CNTs/TinO2n-1 foam were prepared by hydrochloric acid (HCl) induced self-assembly and freeze-drying, during which oxygen-vacancies-rich TinO2n-1 quantum dots in situ grown on Ti3CNTx nanoflakes as a result of their slight and spontaneous oxidation. The well-developed pore structure, abundant interfaces, unique dangling bonds, defects and terminated groups on highly conductive Ti3CNTxnanoflakes, as well as the oxygen vacancies in TinO2n-1 quantum dots render the foams with superior impedance matching, intensive multiple reflection and dielectric loss. By immersing the foams into molten paraffin (absorber content: 4.2wt%), excellent microwave absorption (MA) properties were achieved: an effective absorption band width (EAB) of 5.2 GHz (1.55 mm) and a reflection loss (RL) of -81.3 dB (1.85 mm) for Ti3CNTx/TinO2n-1foam, and an EAB of 6.4 GHz and a RL of -54.3 dB (1.85 mm) for Ti3CNTx/CNTs/TinO2n-1 foam (15wt% CNTs). Moderate addition of CNTs enhanced the conduction loss and polarization loss, leading to a larger EAB. When adjusting the thickness (1.2-5 mm), the EAB of Ti3CNTx/TinO2n-1 foam (14.7 GHz) and Ti3CNTx/CNTs/TinO2n-1 foam (15.3 GHz) both covered the C, X and Ku band. This work offers a simple and facile method for constructing Ti3CNTx-based foams as excellent MA materials.

ZIF-67 and Biomass-Derived N, S-Codoped Activated Carbon Composite Derivative for High-Effective Removal of Hydroquinone from Water.

Hydroquinone (HQ) in wastewater is of great concern, as it is harmful to human health and threatens the ecological environment. However, the existing adsorbents have low adsorption capacity for HQ. To improve the removal of HQ, N,S-codoped activated carbon-ZIF-67 (NSAC-ZIF-67@C) was synthesized in this study by in situ growth of ZIF-67 on N,S-codoped activated carbon (NSAC) and carbonization. The influence of pH, contact time, and initial concentration on the adsorption behaviors of NSAC-ZIF-67@C on HQ were investigated. Owing to the synergistic effect of abundant active sites and well-developed pore structure, the NSAC-ZIF-67@C achieved a prominent adsorption capacity of 962 mg·g-1 and can still retain high adsorption performance after 5 cycles for HQ, which is superior to that of reported other adsorbents. HQ adsorption follows the pseudo-second-order kinetics model (R2 = 0.99999) and the Freundlich isotherm model. X-ray photoelectron spectroscopy (XPS) analysis before and after adsorption as well as density functional theory (DFT) calculation results showed that pyridinic-N-termini were conducive to the π-π interactions and hydrogen-bonding interactions. Therefore, the adsorption mechanisms of NSAC-ZIF-67@C on HQ involve pore filling, electrostatic attraction, π-π interaction, and hydrogen bonding. This study is expected to provide a reference for designing highly effective adsorbents for wastewater treatment.

Seeking the adsorption of tetracycline in water by Fe-modified sludge biochar at different pyrolysis temperatures.

The composite material SBC-Fe-x with sludge and Fe3+ was developed by different calcination temperatures (600, 700, and 800 °C) for the removal of tetracycline (TC). The adsorption rates of SBC-Fe-600, SBC-Fe-700, and SBC-Fe-800 were 77.5%, 89%, and 91%, respectively. Furthermore, the Langmuir model indicated that the maximum adsorption capacity of SBC-Fe-700 (157.93 mg/g) was three times greater than that of SBC-Fe-600. The conclusions were confirmed by a series of characterizations that SBC-Fe-700 showed a larger specific surface area, well-developed pore structure, rich oxygen-containing functional groups and a high degree of graphitization. The results of pH experiments indicated the broad applicability of SBC-Fe-700 for TC adsorption. In addition, SBC-Fe-700 suggested outstanding performance in different water environments. This work produced a feasible adsorbent for the removal of TC, and a new direction for sludge resource utilization was proposed.

F, O co-doped porous hard carbon from conjugated microporous polymer for efficient lithium storage

Hard carbon is a promising alternative to conventional graphite due to its adjustable chemical composition and amorphous structure. Herein, F, O co-doped hard carbon (FOPHC) is constructed from F-containing conjugated microporous polymers, which is synthesized from 1,3,5-triethynylbenzene and 1,4-dibromotetrafluorobenzene. BET, XPS, and EDS analyses demonstrate that FOPHC is a nanoparticle with a hierarchical pore structure and F, O co-doping. When evaluated as an anode for LIBs, the FOPHC delivers an impressive 781 mA h g−1 at 0.1 A/g and 420 mA h g−1 at 0.6 A/g after 300 cycles. Kinetic calculation reveals that the dominated pseudocapacitance contribution of Li-storage in FOPHC (67.5 %, at 1.0 mV/s), attributed to the well-developed hierarchical pore structure and abundant defect sites. This work provides original insights for the microstructure regulation and design of hard carbon.

Layered double oxide (CoAl-LDO) catalysis for enhanced ozonation of methyl orange: Performance assessment and mechanistic insights

In this study, we report the successful synthesis of a novel layered double oxide (CoAl-LDO) ozone catalyst through co-precipitation and high-temperature calcination method, utilizing layered double hydroxide (CoAl-LDH) as an uncalcined intermediate product. The synthesized CoAl-LDO exhibits a thinner and more curved plate-like morphology with well-developed porous structures, demonstrating richer content of active oxygen species and enhanced oxygen migration ability. Notably, the CoAl-LDO catalyst demonstrates superior catalytic performance compared to conventional catalysts and ozone alone systems. Utilizing methyl orange (MO) as the target pollutant, CoAl-LDO catalyzed ozonation achieved an impressive removal rate of 88.27 % within 10 min, surpassing the performance of CoAl-LDH (61.84 %), Co3O4 (57.71 %), and O3 alone systems (47.71 %). Moreover, the CoAl-LDO catalyst exhibited excellent stability and reusability, maintaining a removal rate above 72.13 % over four consecutive cycles. In addition, we propose a novel reaction mechanism for the catalytic ozonation based on the interconversion of Co2+ and Co3+ during the reaction process to generate oxygen vacancies (OV), which in turn react with water molecules and ozone molecules to produce ROS (especially O2−). These findings provide unique perspectives for the precise design and rational application of ozone catalysts.

Efficient production of activated carbon with well-developed pore structure based on fast pyrolysis-physical activation

As the most commonly used method for industrial activated carbon preparation, physical activation is usually accompanied by significant loss of raw materials, especially when the pore structure of activated carbon is well developed. This not only reduces yields, but also increases costs. To enhance both yield and pore structure of activated carbon, we proposed a facile and scalable method called "fast pyrolysis-physical activation". After fast pyrolysis, although the initial pore volume of the semi-coke decreases, the rapid release of volatiles promotes the increase of mesopore and macropore volumes and the development of micron-scale cracks, which is beneficial for CO2 mass transfer and reduces diffusion resistance. Therefore, compared to slow pyrolysis, the activated carbon produced through this method has a higher pore volume (increased by 25.9 %–30.0 %) and a larger SBET (increased by 26.7 %–38.3 %), while the yield remains almost unchanged. Consequently, due to the increase in pore volume and high yield of the activated carbon, the CO2 adsorption capacity (25 °C, 1 bar) of ACB-K700 increases from 2.02 mmol/g to 2.37 mmol/g compared to ACB-M700, and the total CO2 adsorption capacity of activated carbon prepared from the same mass of raw coal (1 g) increases from 1.07 mmol to 1.16 mmol. Due to the pre-formed pores inside the semi-coke, the gas activator molecules are able to penetrate deep into the particles, which not only reduces the ineffective etching that occurs on the surface, but also promotes the development of pore structure. In conclusion, this study provides a new pore development model for physical activation, and also provides a new method to produce activated carbon rapidly and massively, while the pore structure is well developed.

Rice husk waste-derived super-biochar with the max surface area and Philic-CO2 textural structure: Boosting effect and mechanism of post-desilication

A super-carbon material as adsorbents of CO2 were prepared with rice husk waste by a new two-step process, pyrolysis-activation and HF post-desilication process. This paper was focused on investigating the boosting effect and mechanism of post-desilication. It was found that the function of the post-desilication was considerably different from that of the reported pre-desilication. It could not only effectively remove Si element from rice husk biochar (RHC) but also significantly improve its performance, producing a super-biocarbon with a well-developed pore structure, rich C-F groups, and a 4230-m2 g−1 surface area, which is the max surface area of known biocarbon. It could adsorb 341.5 mg g−1 CO2, a max CO2 adsorption capacity of reported biocarbon, and its CO2/N2 and CO2/H2O adsorption selectivity index reached as high as 22.2 and 2.1, respectively. The large surface area was mainly originated from the expansion effect of SiF4 gas from the post-desilication, generating numerous ultra-microspores, while these C-F groups were generated by the co-reactions of the post-desilication. The ultra-high adsorption capacity was mainly from the fill-adsorption driven by the size effect of these ultra-micropores and the strong CO2-affinity of C-F groups, and the adsorption selectivity was confirmed to depend on water-resistant and CO2-philic characteristics of its C-F groups by theoretical calculations and experimental observations. These findings presented not only an advanced CO2-capture material but also a facile way to tailor textural structure of other biochars.

Recent Advances in Preparation and Structure of Polyurethane Porous Materials for Sound Absorbing Application.

Various acoustic materials are developed to resolve noise pollution problem in many industries. Especially, materials with porous structure are broadly used to absorb sound energy in civil construction and transportation area. Polyurethane (PU) porous materials possess excellent damping properties, good toughness, and well-developed pore structures, which have a broad application prospect in sound absorption field. This work aims to summarize the recent progress of fabrication and structure for PU porous materials in sound absorption application. The sound absorption mechanisms of porous materials are introduced. Different kinds of structure for typical PU porous materials in sound absorption application are covered and highlighted, which include PU foam, modified PU porous materials, aerogel, templated PU, and special PU porous materials. Finally, the development direction and existing problems of PU material in sound absorption application are briefly prospected. It can be expected that porous PU with high sound absorption coefficient can be obtained by using some facile methods. The design and accurate regulation of porous structures or construction of multilayer sound absorption structure is favorably recommended to fulfill the high demand of industrial and commercial applications in the future work.

Engineered Multi-Shelled hollow mesoporous organosilica for efficient Pb(II) and Cr(VI) removal

Adsorbents with fast kinetics and high capacity have always been attractive for wastewater treatment. Herein, multi-shelled hollow mesoporous organosilica functionalized by hydroxyphosphatoethyl groups on dual-pore surfaces (P-HMO) is prepared by general one-pot co-condensation. The resulting P-HMO exhibits high hydrophilicity, large surface area and well-developed pore structure, providing P-HMO fast adsorption kinetics (C0 = 320 mg·L-1, equilibrium within 5 min) and ultrahigh adsorption efficiency for Pb(II) and Cr(VI), the adsorption capacity reaches 1056.53 and 869.56 mg·g−1, respectively. Furthermore, P-HMO displays outstanding reusability over 10 adsorption–desorption cycles thanks to the stable framework structure that can resist wear and tear during water treatment. The advantages of long service life, high efficiency and broad pH range make P-HMO promising in industrial water purification.

High-performance electrosorption of lanthanum ion by Mn3O4-loaded phosphorus-doped porous carbon electrodes via capacitive deionization

Transition-metal-oxide@heteroatom doped porous carbon composites have attracted considerable research interest because of their large theoretical adsorption capacity, excellent electrical conductivity and well-developed pore structure. Herein, Mn3O4-loaded phosphorus-doped porous carbon composites (Mn3O4@PC-900) were designed and fabricated for the electrosorption of La3+ in aqueous solutions. Due to the synergistic effect between Mn3O4 and PC-900, and the active sites provided by Mn–O–Mn, C/PO, C–P–O and Mn–OH, Mn3O4@PC-900 exhibits high electrosorption performance. The electrosorption value of Mn3O4@PC-900 was 45.34% higher than that of PC-900, reaching 93.02 mg g−1. Moreover, the adsorption selectivity reached 87.93% and 89.27% in La3+/Ca2+ and La3+/Na+ coexistence system, respectively. After 15 adsorption-desorption cycles, its adsorption capacity and retention rate were 50.34 mg g−1 and 54.12%, respectively. The electrosorption process is that La3+ first accesses the pores of Mn3O4@PC-900 to generate an electric double layer (EDL), and then undergoes further Faradaic reaction with Mn3O4 and phosphorus-containing functional groups through intercalation, surface adsorption and complexation. This work is hoped to offer a new idea for exploring transition-metal-oxide @ heteroatom doped porous carbon composites for separation and recovery of rare earth elements (REEs) by capacitive deionization.

Dual-function highly oxidative potassium salts empowering high-performance transition metal oxide/activated carbon for hybrid aqueous supercapacitors

In this work, a novel strategy of high-temperature oxidation-activation followed by rapid low-temperature aqueous-reflux treatment is developed to prepare transition metal oxide-activated carbon (TMO-AC) composites for supercapacitor applications. The super-absorbent polymer is selected as the carbon source, and the highly oxidative potassium salts K2FeO4/KMnO4 serve as both precursors for TMO and activators for AC. AC possesses a well-developed porous structure. Moreover, TMO grows uniformly in-situ on AC surface and displays a small size below 10 nm. The prepared Fe2O3-ACFe and MnO2-ACMn composites exhibit remarkable specific capacitance of 645.0 and 548.0 F g−1, respectively. Hybrid aqueous supercapacitors are assembled with Fe2O3-ACFe and MnO2-ACMn as negative and positive electrodes, respectively. A stable operating voltage of 1.2 V is achieved in the KOH electrolyte, resulting in a remarkable 90.2% capacitance retention over 10,000 cycles. Furthermore, in the Na2SO4 electrolyte, a wide 1.6 V voltage window is obtained, contributing to a substantial energy density of 49.35 Wh kg−1. This work provides an interesting approach for the fabrication of high-performance TMO-carbon composite electrodes.

Construction of novel coaxial electrospun polyetherimide@polyaniline core-shell fibrous membranes as free-standing flexible electrodes for supercapacitors

Designing porous and flexible electrodes with excellent electrochemical properties is crucial to fabricate high-performance flexible supercapacitors. Conductive polymer-based electrospun fibers are expected to be an ideal material for constructing flexible electrodes due to the enormous specific surface area, unique pore structure and inherent flexibility. However, the exploration of such electrospun fibers with facile preparation methods and high areal capacitance remains challenging. Herein, a novel polyetherimide@polyaniline core-shell fibrous membranes (PEI@PANI CFMs) is fabricated via simply coaxial electrospinning and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPS) secondary doping. With the aid of polyetherimide, highly concentrated emeraldine base polyaniline (EB-PANI) can be perfectly wrapped on the surface of fibers without any spinning assistants, ensuring the well-developed pore structures, superior hydrophilicity, good electrical conductivity and outstanding mechanical flexibility. Benefiting from the synergistic effect of structure and constituents, such flexible PEI@PANI CFMs as electrode materials can provide more accessible electrochemical active sites and decrease the ion diffusion resistance. Therefore, the PEI@PANI CFMs present outstanding areal capacitance of 1159.9 mF cm−2 and remarkable energy density of 46.91 μW h cm−2 in the electrodes and symmetric supercapacitors, demonstrating great potential for applications in flexible energy storage field. This fabrication strategy provides a simple and practicable way to manufacture polyaniline-based fibrous membranes for high-performance flexible electrode materials.

Co-pyrolysis and activation of microalgae and waste polypropylene in the synthesis of nitrogen doped and porous carbon for pollutant adsorption

Algae and waste plastics are two promising raw materials for the preparation of carbon-based adsorbents, which are regarded as the promising adsorbent to remove pollutants in wastewater. To obtain an activated carbon with well-developed porous structure and abundant functional groups, the mixture of H-rich disposable waste polypropylene (WP) and N-rich Chlorella vulgaris (CV) were selected as precursors through co-pyrolysis and KOH activation. The optimum mass ratio of WP and CV for preparing co-pyrolysis carbon (CPC) was 1:3, while the optimum mass ratio of CPC and KOH for preparing co-pyrolysis activated carbon (CAC) was 1:5 at the activation temperature of 800 °C. The morphologies, mean pore diameter, material surface element and degree of graphitization of CAC were analyzed by SEM, BET, XRD, XPS and Raman spectroscopy, respectively. The adsorption kinetics and thermodynamics of tetracycline (TC) onto CPC were investigated. And the sustainability of algal-based activated carbon in adsorption of pollutants has been tested. This study provides a synthesis method of CAC by using algal-based biomass and waste plastics for the absorption of organic pollutants in wastewaters.

Optimization of hydrothermal synthesis conditions of Bidens pilosa-derived NiFe2O4@AC for dye adsorption using response surface methodology and Box-Behnken design.

The presence of stable and hazardous organic dyes in industrial effluents poses significant risks to both public health and the environment. Activated carbons and biochars are widely used adsorbents for removal of these pollutants, but they often have several disadvantages such as poor recoverability and inseparability from water in the post-adsorption process. Incorporating a magnetic component into activated carbons can address these drawbacks. This study aims to optimizing the production of NiFe2O4-loaded activated carbon (NiFe2O4@AC) derived from a Bidens pilosa biomass source through a hydrothermal method for the adsorption of Rhodamine B (RhB), methyl orange (MO), and methyl red (MR) dyes. Response surface methodology (RSM) and Box-Behnken design (BBD) were applied to analyze the key synthesis factors such as NiFe2O4 loading percentage (10-50%), hydrothermal temperature (120-180 °C), and reaction time (6-18 h). The optimized condition was found at a NiFe2O4 loading of 19.93%, a temperature of 135.55 °C, and a reaction time of 16.54 h. The optimum NiFe2O4@AC demonstrated excellent sorption efficiencies of higher than 92.98-97.10% against all three dyes. This adsorbent was characterized, exhibiting a well-developed porous structure with a high surface area of 973.5 m2 g-1. Kinetic and isotherm were studied with the best fit of pseudo-second-order, and Freundlich or Temkin. Qmax values were determined to be 204.07, 266.16, and 177.70 mg g-1 for RhB, MO, and MR, respectively. By selecting HCl as an elution, NiFe2O4@AC could be efficiently reused for at least 4 cycles. Thus, the Bidens pilosa-derived NiFe2O4@AC can be a promising material for effective and recyclable removal of dye pollutants from wastewater.

Fabrication of metal oxides-based adsorbents for SO2 capture with equimolar adsorption

A series of novel porous metal oxides (MO, M = Mg, Ca, Ba, Mn and Zn) adsorbents were synthesized through simple thermal treatment of the corresponding metal sulfite for the remotion of sulfur dioxide (SO2). The obtained MO adsorbents were characterized by various techniques including scanning electron microscopy (SEM), thermal gravimetric analyzer (TGA), X-ray diffraction (XRD) and nitrogen adsorption studies. The results show that the SO2 adsorption capacity of manganese oxide (MnO) is much higher than that of other MO. And due to its highly dispersed and large specific surface area, especially its well-developed pore structure, equimolar adsorption of SO2 can be achieved for the first time among similar SO2 adsorbents. In addition, different sources of MnO were explored and it was found that the MnO obtained from the decomposition of MnSO3 had the highest SO2 adsorption capacity. Adsorption kinetic studies show that the reaction between MnO and SO2 conforms to the pseudo-second-order kinetic equation. Furthermore, it was found through seven-cycle experiments that the adsorption amount tended to stabilize in each of the following cycles, except for the first high temperature, which led to changes in the adsorbent and a decrease in cycling performance. This strategy has three advantages: one-step preparation at low temperatures, equimolar adsorption of SO2 as well as good reusability and selectivity.

Novel synthesis and characterization of magnesium-doped CoFe2O4 nanoparticles –SiO2 –3-aminopropylethoxysilane– gallic acid magnetic nanocomposite for effective removal of cationic dyes

Magnesium-doped CoFe2O4 nanoparticles (MgCF)@SiO2-NH-COOH were prepared through a step-wise procedure for the removal of two cationic dyes from real wastewater. MgCF was successfully synthesized through the co-precipitation technique. Subsequently, these nanoparticles were coated within a silica (SiO2) shell and functionalized with amino groups utilizing 3-Aminopropylethoxysilane (APTES). To assess its adsorption capabilities, the nanocomposite underwent further modification with Gallic acid (GA). MgCF@SiO2-NH-COOH has a well-developed pore structure with a BET surface area of 31.655m2/g, which also has a crystalline structure. Adsorption tests revealed the excellent performance of MgCF@SiO2-NH-COOH in removing Methylene Blue (MB) and Rhodamine B (RhB) dyes. Kinetic studies demonstrated that the adsorption of MB and RhB followed the Boyd kinetic model. The Langmuir isotherm model provided the best fit for the experimental data, with a maximum adsorption capacity of 103 mg/g and 89 mg/g for MB and RhB, respectively. Moreover, recycling tests established the high stability and reusability of MgCF-SiO2-APTES-GA nanocomposites, with consistent adsorption performance over at least five cycles. At the first stage, the adsorption was 98.6 % for MB and 95.3 % for RhB, and after five regenerations, the adsorption was 82.5 % for MB and 79.6 % for RhB. This research offers a cost-effective compound that addresses pressing environmental concerns related to the removal of organic dyes from wastewater.

Composition, structural, physicochemical and functional properties of dietary fiber from different milling fractions of black rice bran

Black rice bran is a superior dietary fiber (DF) resource. However, the lack of specific distribution and functionality of DF in black rice bran has constrained its refined processing. This study divided black rice bran into five equal bran fractions (BF) by stepwise milling to obtain BF1(outermost layer) to BF5 (the innermost layer). The contents, structure, physicochemical and functional properties of DF in each bran fractions were investigated. The results revealed that the insoluble, soluble and total dietary fiber (IDF, SDF and TDF) contents were 17.52 ± 0.48 to 31.14 ± 0.96, 2.03 ± 0.20 to 3.86 ± 0.01 and 19.57 ± 0.28 to 34.61 ± 1.10 g/100 g dry basis, respectively. Compared to BF1, the TDF content of BF2–BF5 was reduced by 3.90, 3.20, 21.74 and 43.46%, respectively. The main monosaccharides in both IDF and SDF were xylose, glucose, arabinose and galactose. The molecular weight of SDF samples ranged from 17.19 ± 1.95 to 36.32 ± 0.80 kDa. The outer bran fractions (BF1–BF3) IDF exhibited higher water swelling, water retention, oil adsorption capacity, together with cholesterol and sodium nitrite adsorption capacity than those of inner bran fractions (BF4–BF5), owing to their lower crystallinity and well-developed porous structure. These results provide essential data for the development of black rice DF-based food processing with enhanced functional benefits.

Molecular sieve-like wood achieves efficient chiral catalysis

Molecular sieve catalysts have been adopted in chiral catalytic reactions due to their high specific surface area, nano-scaled pores and effective separation, however, the problems like low utilization ratio of channels, difficult modification, long period and complex preparation, and no economic benefits reduce its widely application. In this paper, natural wood was employed as raw material to preserve the cellulose skeleton rich in poly‑hydroxyl and the multistage porous channels of nanometer, micron and millimeter by simple treatment. A low-cost, high-yield and high-selectivity chiral catalyst could be obtained from wood with chiral catalytic sites. The in situ grafting method retains the well-developed multistage pore structure of wood, enhances the mass transfer and possesses universal applicability to different aldol condensation reactions. The asymmetric reaction of cyclohexanone and p-nitrobenzaldehyde is catalyzed by grafting readily available amino acids such as threonine, with a yield of 82% and selectivity of 57%. Molecular sieve-like wood possesses the advantages of low economic cost and good catalytic performance, which provides a potential possibility to replace traditional molecular sieve catalyst.

Preparation and characterization of polyvinyl chloride based carbon materials with high specific surface area

Using PVC as raw material and KOH as activator, the carbon adsorption material with ultra-high specific surface area up to 5677.2 m2/g was prepared by chemical activation method, and its structure was characterized to study its adsorption performance on methylene blue solution; the activated mixture was analyzed for chlorine element and the recovery of chlorine element was calculated. The results show that the surface of the obtained activated carbon material is in the shape of smooth lotus root flakes with well-developed pore structure; the adsorption value of methylene blue adsorption can reach 765.0 mg/g, which can adsorb methylene blue solution quickly and efficiently; the elemental chlorine can be recovered efficiently with a recovery rate of 95.33 %, which can effectively reduce the toxic hydrogen chloride gas produced in the process of PVC pyrolysis. Excellent adsorption capacity of H2, CO2 and CH4. This experiment can provide an effective method for the harmless treatment of PVC.