Fe loading 3D micro-meso-porous carbon sphere derived from natural cellulose of sawdust activating peroxymonosulfate for degradation of enrofloxacin.

Fe loading 3D micro-meso-porous carbon sphere (Fe@3C-2N) was derived from natural cellulose of sawdust and melamine through sodium alginate and ferric chloride cross-linking followed by carbonization processes, which served as peroxymonosulfate (PMS) activators for enrofloxacin (ENR) degradation. The cellulose was produced by the delignification of sawdust with sodium chlorite. The delignification of sawdust and the addition of melamine increased the porosity and electron transport capacity of Fe@3C-2N. When the dosages of Fe@3C-2N and PMS were 0.60 g L-1 and 0.20 g L-1 respectively, the degradation rate of ENR (20 mg L-1) reached 92.17 % within 80 min, suggesting the satisfactory activation performance of PMS. The good structural stability of Fe@3C-2N makes it suitable for use as packing in continuous flow reactors for wastewater treatment. Quenching experiments and electron paramagnetic resonance (EPR) suggested that SO4•- and 1O2 were the dominant reactive oxygen species (ROSs) in Fe@3C-2N/PMS system. X-ray photoelectron spectroscopy (XPS) revealed that Fe3C, pyrrolic N and graphitic N were the potential active sites.

Starch of oat derived nanostructured Fe/Mn bimetallic carbon materials for sulfamethoxazole degradation via peroxymonosulfate activation.

Fe/Mn bimetallic carbon materials were synthesized by combining oat and urea, followed by and carbonization processes, the activity and mechanism of the obtained materials in activating peroxymonosulfate (PMS) for sulfamethoxazole (SMX) degradation were determined. Data suggested that the obtained material (CN@FeMn-10-800) showed the optimal performance for SMX degradation under the1:8:0.05:0.05 mass ratios of oat/urea/Fe/Mn. Around 91.2 % SMX (10 mg L-1) was removed under the conditions of 0.15 g L-1 CN@FeMn-10-800 and 0.20 g L-1 PMS. The CN@FeMn-10-800 showed great adaptability under different conditions, satisfactory activation repeatability and versatility. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) demonstrated that core-shell structure with rich porous of CN@FeMn-10-800 was achieved. Quenching test and electron paramagnetic resonance (EPR) indicated that surface bound oxygen and singlet oxygen (1O2) were the dominate reactive groups in this system. X-ray photoelectron spectroscopy (XPS) suggested that graphite N, Fe0, Fe3C and Mn(II) were the dominant active sites. Through the work, a simple strategy could be found to make high-value use of biomass and use it to effectively purified wastewater.

Magnetic porous carbon materials derived from metal-organic framework in-situ growth on natural cellulose of wood for sulfadiazine degradation: Role of delignification and mechanisms.

Magnetic porous carbon materials as peroxymonosulfate (PMS) activators for sulfadiazine degradation were derived from metal-organic frameworks (MOFs) grown in-situ on the cellulose of wood through the one-step pyrolysis method. The cellulose was obtained by treating wood powder with sodium chlorite to remove lignin, and Fe-MOFs (MIL-101(Fe)) nanoparticles were in-situ grown on the cellulose through hydrothermal reaction. The delignification of wood effectively enhanced the in-situ growth of MIL-101(Fe) on the wood tracheid skeleton, increased the specific surface area of magnetic porous carbon material (Fe@PC-50) after pyrolysis, and improved the performance of Fe@PC-50 as a PMS activator for the degradation of sulfadiazine. With the presence of 0.04 g L-1 Fe@PC-50 and 0.12 g L-1 PMS, the degradation percentage of sulfadiazine (20 mg L-1) could reach 100 % within 15 min, indicating excellent catalytic activity. Quenching tests and electron paramagnetic resonance (EPR) indicated that both free and non-free radicals played important roles in PMS activation. X-ray photoelectron spectroscopy (XPS) suggested that Fe0 and Fe3C were the possible important active sites for sulfadiazine degradation. This work offered an effective method to synthesize PMS activators from biomass/MOF materials for water treatment.

Nitrogen doped magnetic porous carbon derived from starch of oatmeal for efficient activation peroxymonosulfate to degradation sulfadiazine.

Nitrogen doped magnetic porous carbon catalyst based on starch of oatmeal was obtained by mixing and pyrolysis process, and its catalytic activity of peroxymonosulfate activation for sulfadiazine degradation was evaluated. When ratio of oatmeal/urea/iron was 1: 2: 0.1, CN@Fe-10 had the best catalytic activity to degrade sulfadiazine. Around 97.8 % removal of 20 mg L-1 sulfadiazine was achieved under incorporating of 0.05 g L-1 catalyst and 0.20 g L-1 peroxymonosulfate. Good adaptability, stability and universality of CN@Fe-10 were verified under different conditions. Electron paramagnetic resonance and radical quenching test suggested that surface-bound reactive oxides species and singlet oxygen were the main reactive oxides species in this reaction. Electrochemical analysis indicated that CN@Fe-10 had a good electrical conductivity and electron transferred did occur among CN@Fe-10 surface, peroxymonosulfate and sulfadiazine. X-ray photoelectron spectroscopy suggested that Fe0, Fe3C, pyridine nitrogen and graphite nitrogen were the potential active sites for peroxymonosulfate activation. Therefore, the work provided a practical approach for recycling biomass.

Preparation of a Montmorillonite-Modified Chitosan Film-Loaded Palladium Heterogeneous Catalyst and its Application in the Preparation of Biphenyl Compounds.

The natural polymer chitosan was modified with polyvinyl alcohol to enhance the mechanical properties of the membrane, and then, the montmorillonite-modified chitosan-loaded palladium catalyst was prepared using the excellent coordination properties of montmorillonite. The results showed that the catalyst has good tensile strength, thermal stability, catalytic activity, and recycling performance and is a green catalytic material with industrial application potential.

Iron and nitrogen co-doped porous carbon derived from natural cellulose of wood activating peroxymonosulfate for degradation of tetracycline: Role of delignification and mechanisms.

Iron and nitrogen co-doped porous carbon materials as peroxymonosulfate (PMS) activator for tetracycline (TC) degradation were prepared by pyrolyzing the mixture of iron loading cellulose and melamine under N2 flow. The cellulose obtained from balsawood through delignification with sodium chlorite. The delignification of wood obviously improved the specific surface area and enhanced the catalytic efficiency of carbon materials obtained after pyrolysis. Enhancing graphitization degree of carbon material demonstrated that delignification of wood was conducive to formation of a short-range ordered graphitic structure during pyrolysis, which facilitated to the improvement of adsorption/catalytic performance of the carbon materials. The prepared catalyst exhibited excellent catalytic stability and adaptability under the conditions of different systems. Radical quenching test and electron paramagnetic resonance measurements suggested that superoxide radical (O2·-) and singlet oxygen (1O2) played dominant roles in TC degradation. Fe0/Fe3C, pyridine N and graphite N were the dominant active sites for PMS activation. This research provides new insights for the development of biomass derived high performance carbon catalysts and their application in wastewater treatment via PMS based advanced oxidation processes.

Copper Foam as Active Catalysts for the Borylation of α, ß-Unsaturated Compounds.

The use of simple, inexpensive, and efficient methods to construct carbon-boron and carbon-oxygen bonds has been a hot research topic in organic synthesis. We demonstrated that the desired ß-boronic acid products can be obtained under mild conditions using copper foam as an efficient heterogeneous catalyst. The structure of copper foam before and after the reaction was investigated by polarized light microscopy (PM), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the results have shown that the structure of the catalyst copper foam remained unchanged before and after the reaction. The XPS test results showed that the Cu(0) content increased after the reaction, indicating that copper may be involved in the boron addition reaction. The specific optimization conditions were as follows: CH3COCH3 and H2O were used as mixed solvents, 4-methoxychalcone was used as the raw material, 8 mg of catalyst was used and the reaction was carried out at room temperature and under air for 10 h. The yield of the product obtained was up to 92%, and the catalytic efficiency of the catalytic material remained largely unchanged after five cycles of use.

Preparation of Bentonite/Chitosan Composite for Bleaching of Deteriorating Transformer Oil.

A novel adsorbent containing chitosan (CS) and bentonite (BT) was developed by mixing, drying, and calcining, and used as an adsorbent for the efficient bleaching of deteriorating transformer oil. The effects of calcination temperature, dosage of CS, adsorbent content, adsorption temperature, and adsorption time on the bleaching capacity of transformer oil were investigated. The structure of the adsorbent was also investigated by Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), transmission electron microscopy (TEM), and N2 adsorption-desorption isotherm techniques. The results showed that there was only physical interaction between CS and BT; CS did transform to carbon (C) and covered the surface of BT. The specific surface area and micropore volume of the adsorbent were affected by the calcination process. The composite adsorbent offered an excellent bleaching performance. When the calcination temperature was 300 °C and dosage of CS was 5%, the composite adsorbent had the optimum bleaching properties. When the composite adsorbent content was 4%, the adsorption temperature was 50 °C and the adsorption time was 75 min, the colour number and transmittance of the deteriorating transformer oil decreased from no. 10 to no. 1 and increased from 70.1% to 99.5%, respectively.

Intermolecular Reductive Heck Reaction of Unactivated Aliphatic Alkenes with Organohalides.

A general intermolecular reductive Heck reaction of organohalides with both terminal and internal unactivated aliphatic alkenes has been first realized in high yield with complete anti-Markovnikov selectivity. The challenging vinyl bromides, aryl chlorides, and polysubstituted internal alkenes were first applied. More than 100 remote carbofunctionalized alkyl carboxylic acid derivatives were rapidly synthesized from easily accessible starting materials. The synthesis of drug molecules has further demonstrated the wide synthetic utility of this scalable strategy. Preliminary mechanistic studies are consistent with the proposed catalytic cycle.

Influence of Nano Titanium Dioxide and Clove Oil on Chitosan-Starch Film Characteristics.

The combined effects of nano titanium dioxide (TiO2-N) and clove oil (CO) on the physico-chemical, biological and structural properties of chitosan (CH)/starch (ST) films were investigated by using a solvent casting method. Results indicated that the incorporation of TiO2-N could improve the compactness of the film, increase the tensile strength (TS) and antioxidant activity, and decrease the water vapour permeability (WVP). As may be expected, the incorporation of CO into the film matrix decreased TS but increased the hydrophobicity as well as water vapour barrier antimicrobial and antioxidant properties. Fourier-transform infrared spectroscopy (FTIR) data supported intermolecular interactions between TiO2-N, CO and the film matrix. Use of a scanning electron microscope (SEM) showed that TiO2-N and CO were well dispersed and emulsified in the film network. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves demonstrated that TiO2-N and CO were well embedded in the film matrix, hence this blend film system could provide new formulation options for food packaging materials in the future.

Preparation of Modified Chitosan Microsphere-Supported Copper Catalysts for the Borylation of α,ß-Unsaturated Compounds.

Chitosan microspheres modified by 2-pyridinecarboxaldehyde were prepared and used in the construction of a heterogeneous catalyst loaded with nano-Cu prepared by a reduction reaction. The chemical structure of the catalyst was investigated by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), and X-ray Photoelectron Spectroscopy (XPS). Under mild conditions, such as no ligand at room temperature, the catalyst was successfully applied to catalyze the borylation of α,ß-unsaturated receptors in a water-methanol medium, yielding 17%-100% of the corresponding -hydroxy product. Even after repeated use five times, the catalyst still exhibited excellent catalytic activity.

Chitosan-acorn starch-eugenol edible film: Physico-chemical, barrier, antimicrobial, antioxidant and structural properties.

Edible films from chitosan (CH) containing various amount of acorn starch (AS) and eugenol (Eu) were developed by casting and solvent-evaporation method, and their physico-chemical, barrier, antimicrobial, antioxidant and structural properties were also investigated. The experimental data showed that an appropriate proportion of AS could improve the mechanical and barrier properties of the film, and the incorporation of Eu in the film significantly improved the flexibility, barrier, hydrophobicity, antimicrobial and antioxidant properties. The results showed that the optimum comprehensive properties of the film were obtained when the mass ratio of AS to CH was 0.9 and the content of Eu was 9%. Possible intermolecular interactions between CH, AS and Eu were confirmed by Fourier-transform infrared spectroscopy (FTIR). SEM indicated that a good compatibility was present between CH and AS, and Eu was well emulsified and dispersed in the film matrix network. TG and DTG curves further confirmed Eu present in the film matrix network. Such edible films can provide new ways for packaging industries in developing active packaging materials.

Preparation and characterisation of carboxymethyl-chitosan/sodium phytate composite membranes for adsorption in transformer oil.

Adsorption of metal impurities from transformer oil was studied using a novel porous membrane. A solution of N, O­carboxymethyl­chitosan (CMC) and sodium phytate (SP) was blended to prepare a novel porous membrane for the metal impurities adsorption from transformer oil. The chemical structure of the membranes was characterised by their FTIR spectra, scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and video camera observations. The effects of the SP content of the membrane, contact time, and contact temperature on adsorption of copper, iron, and aluminium impurities were studied. The FTIR spectra and thermogravimetric curves of the membranes indicated good compatibility between CMC and SP. The SEM and video camera observations suggested that CMC-SP composite membranes had a mature, porous structure. The experimental results showed that the SP content significantly affected the adsorption capacity of a CMC membrane. The maximum adsorption percentages of elemental copper, iron, and aluminium were 88.12%, 82.35%, and 80.36% when the SP ratio was 80% at 60 °C.

Physical, antibacterial and antioxidant properties of chitosan films containing hardleaf oatchestnut starch and Litsea cubeba oil.

More and more attention was attached to food safety, it is necessary to endow food packaging films with good antibacterial and antioxidant properties Edible films based on chitosan (CH), hardleaf oatchestnut starch (HOS) and Litsea cubeba oil (LEO) were prepared by solution casting. The properties and structures of the blend film with different proportion (xCH/yHOS) were evaluated. The CH-HOS films were firstly prepared by blending CH solution with HOS paste. The tensile strength (TS) and DPPH radical scavenging ability of CH-HOS films increased from 27.33 MPa to 33.54 MPa and 20.67% to 52.34%, respectively, and water vapor permeability (WVP) decreased from 1.531 × 10-11 g m-1 pa-1 s-1 to 1.491 × 10-11 g m-1 pa-1 s-1, with the HOS content increased from the ratio of 1:0 to 1:1. Then, the LEO was added to 1CH-1HOS films. Tensile strength (TS), water vapor permeability, moisture absorption and total soluble matter (TSM) of the 1CH-1HOS film were remarkably decreased with 16%LEO. Meanwhile, the static contact angle and antimicrobial activity of 1CH-1HOS-16LEO film increased significantly. Hence, this blend film system has great potential for food packaging in the future.

Carbohydrate-conjugated 4-(1,3,2-dithiarsolan-2-yl)aniline as a cytotoxic agent against colorectal cancer.

Arsenic trioxide (As2O3) has been approved for the treatment of acute promyelocytic leukemia (APL); however, its use in the treatment of solid tumors is limited due to its pharmacokinetic properties. Organic arsenic compounds provide better options for pharmaceutical optimization. p-Aminophenyl arsenoxide (p-APAO), an organic arsenic compound, was found to interact with the promyelocytic leukemia-retinoic acid receptor alpha (PML-RARα) fusion protein in a similar manner to arsenic trioxide. Analogs of p-APAO such as 4-(1,3,2-dithiarsolan-2-yl)aniline (p-APDTAs) were recently found to show improved cytotoxicity toward several solid tumor cell lines with lower toxicity to normal cells. Here, we synthesized a carbohydrate-conjugated 4-(1,3,2-dithiarsolan-2-yl)aniline (p-APDTAs) and showed that it exhibited reduced cytotoxicity to normal cells, suggesting a feasible approach to improve the therapeutic index of arsenic-containing compounds as chemotherapeutic agents.