CHEMICAL ENGINEERING JOURNAL
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2019
·
IF 8.355
Cong Li,Hongyang Ma,Shyam Venkateswaran,Benjamin S. Hsiao
Treatment of textile wastewater containing highly toxic dyes and heavy metal ions raises serious health concerns that need to be addressed urgently. Carboxylated cellulose fabric filters were fabricated by 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation and employed to remove heavy metal ions and dyes efficiently by adsorption from simulated wastewater. A series of characterizations including ATR, TGA, and SEM measurements were employed to investigate their structure and morphologies. The carboxylated cellulose fabrics exhibited excellent mechanical properties evidenced by tensile experiments and comparisons with other non-woven counterparts. Lead ion (Pb (II)) and methylene blue (MB) were introduced to investigate the filtration performance of carboxylated cellulose filters; high flux, high rejection ratio, and low pressure drop were achieved due to the internal micro-nanoscaled structure of the cellulose fabrics as revealed by XPS and elemental mapping characterizations. The maximum adsorption capacities for Pb (II) and MB were 81.30 and 76.92 mg/g, respectively, while the pressure drop for dynamic adsorption was as low as 0.07 kPa, indicating that the filtration performance was drivable by gravity. A spiral wound cartridge of cellulose fabrics was fabricated and a long-term filtration performance against multicomponent wastewater containing 2.0 mg/L Pb (II) and 2.0 mg/L MB , simultaneously, was demonstrated. The wastewater treatment capacities of 3.6 g of the filter were up to 21.7 L and 36.1 L, respectively, which was 10-times higher than that of the original cellulose fabrics; and the rejection ratios against MB and Pb (II) were 98.7% and 98.2%, respectively, which met the environmental criteria for wastewater disposal. The recycling and reusability of the filters were also demonstrated, indicating that the carboxylated cellulose fabrics can be considered as sustainable filters for wastewater treatment.
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高影响因子
CELLULOSE
·
2019
·Vol. 26
·期 17
·9135-9147
·
IF 3.917
Zhou Shengqiang,Yang Xiaomei,Zhang Yali,Jiang Lingyun,Zhou Lipeng,Lu Tianliang,Su Yunlai
Abstract One-pot conversion of cellulose to valued-added platform chemicals such as alkyl levulinate is a promising and challenging process of biomass utilization due to the insolubility of cellulose in alcohol. In this work, commercial heteropoly acid combined with postsynthesized Sn-Beta zeolite was employed to transform cellulose to methyl levulinate (MLE) in one pot. The synergistic catalysis of the homogeneous strong Brønsted (B) acid and the solid strong Lewis (L) acid can effectively realize the depolymerization of solid cellulose and the subsequent isomerization, dehydration and hydration steps to MLE. 55% and 62% of MLE yields were obtained from α-cellulose and microcrystalline cellulose, respectively, at 160 °C for 10 h. Various carbohydrates besides cellulose can also be efficiently converted to MLE in high yields over the bifunctional catalyst system. The effects of the amount of B acid and L acid, the reaction temperature and time and the amount of cellulose on the production of MLE were investigated in detail. Finally, the reaction pathway of cellulose to MLE was revealed. Recyclability tests indicated that the binary catalyst can be reused without decrease of catalytic activity. Graphic abstract
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FIBERS AND POLYMERS
·
2019
·Vol. 20
·期 8
·1577-1585
·
IF 1.439
Wan Yizao,Lin Zhonghong,Gan Deqiang,Cui Teng,Wan Meirong,Yao Fanglian,Zhang Quanchao,Luo Honglin
Graphene-based nanomaterials have been used as biomaterials to enhance cell adhesion, growth, and differentiation. However, the effect of graphene materials on cancer cell behavior has not been thoroughly investigated. Herein, we have incorporated graphene oxide (GO) into cellulose acetate (CA) to develop nanofibrous scaffolds for in vitro cancer cell culture, which is a crucial step for drug screening and cancer research. The Go/CA scaffolds were seeded with breast cancer cells and cell viability, proliferation, adhesion, infiltration, and morphology were assessed. Mechanical characterization demonstrated that the mechanical properties of GO/CA scaffolds were significantly better than bare CA scaffold and improved with increasing GO content. More importantly, the in vitro cell studies showed that the cancer cells on GO/CA scaffolds had significantly higher viability and better cell adhesion and growth than bare CA. Our results confirm an important role of GO in improving mechanical properties and cancer cell performance on GO/CA scaffolds. These results suggest the potential of the GO/CA scaffolds as a promising candidate for in vitro cancer models.
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ACS Applied Materials & Interfaces
·
2020
·
IF 8.758
Bing Zhou,Zhen Zhang,Yanli Li,Gaojie Han,Yuezhan Feng,Bo Wang,Dianbo Zhang,Jianmin Ma,Chuntai Liu
Flexible, lightweight, robust, and multifunctional characteristics are greatly desirable for next-generation wearable electromagnetic interference (EMI) shielding materials. In this work, an alternating multilayered structure with robust polymer frame layers and directly contacted conducting layers was designed to prepare high-performance EMI films. Especially, the multilayered films containing alternating cellulose nanofiber (CNF) layers and MXene layers are fabricated via a facile and efficient alternating vacuum filtration approach. Deriving from the mechanical frame effect acted by CNF layers in, which is capable of preventing the nanosized “zigzag” crack in MXene layers from growing to the whole film, the alternating multilayered film (CNF@MXene) revealed the improved mechanical strength (112.5 MPa) and toughness (2.7 MJ m–3) compared to both freestanding MXene film and homogeneous CNF/MXene film. Meanwhile, the directly contacted MXene layers resulted in the increased electrical conductivity from 2 (homogeneous CNF/MXene film) to 621–82 S m–1 (CNF@MXene films). In conjunction with the extra “reflection-absorption-zigzag reflection” mechanism among the alternating multilayers, CNF@MXene films demonstrated an exceptional EMI shielding effectiveness of ∼40 dB in the X-band and K-band and high specific shielding effectiveness up to 7029 dB cm2 g–1 at a thickness of only 0.035 mm. Besides, the excellent mechanical flexibility ensured the stable EMI shielding and electrical properties, which can withstand the folding test more than 1000 times without obvious reduction. Moreover, the excellent electrical conductivity endows the alternating multilayered film with an outstanding and steady Joule heating performance, which could reach more than 100 °C at only 6 V impressed voltage to within 10 s. As a result, our alternating multilayered film with reinforced EMI shielding and Joule heating performance is promising in the next-generation intelligent protection devices applying in cold and complex practical environments.
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PubMed
高影响因子
ACS Applied Polymer Materials
·
2019
·
IF 0
Arun Saini,Chandravati Yadav,Bai-Liang Xue,Nan Wang,Lei Dai,Xinping Li
In this study, a mixed-acid-assisted system utilizing a combination of a weak acid (citric acid, CA) and strong acid (H2SO4, SA) under hydrothermal reaction conditions was proposed for simultaneous preparation and modification (carboxylation) of cellulose nanocrystals (CNCs). Bleached bamboo pulp was used as the cellulose source, and the optimized reaction conditions were further used to produce carboxylated CNCs (cCNCs) from microcrystalline cellulose and Whatman 1 filter paper. Different concentrations of CA and SA (namely, 40 wt % CA (optimized concentration) and 5, 10, 20, and 30 wt % SA) were used for the hydrolytic processing of raw cellulosic material under hydrothermal conditions. The effect of various concentrations of CA and SA on the yield, carboxylate content, microstructure, crystallinity, thermal, and rheological characteristics of cCNCs were methodically investigated and contrasted. The optimized hydrothermal reaction conditions performed for 4 h at 100 °C using a mixture of 40 wt % CA and only 20 wt % SA yielded needle-shaped cCNCs with a yield higher than 70%. The carboxyl functionalization of CNCs was affirmed through Fourier transform infrared spectroscopy and conductometric titrimetric method. The results revealed the carboxylate content of 1.18 mmol/g corresponding to an average degree of oxidation of ∼0.20. The length of nanocrystals lies in the range of 280–420 nm with diameter ranging from 10 to 20 nm, as was perceived through microstructural analytical tools like field emission scanning electron microscopy, transmission electron microscopy, and atomic force microscopy. Dynamic light scattering analysis gives an average size of ∼200 nm. The visual inspection revealed high colloidal stability of cCNCs dispersions, which was further supported through its appreciable Zeta potential value of ca. −49.5 mV. Further, the rheological characterizations revealed typical features reminiscent of critical gels showing elastic behavior of cCNCs. Nanocomposite films of hydroxypropyl methylcellulose (HPMC) with different loadings of cCNCs were fabricated using a simple solvent casting method. The incorporation of very small amounts of cCNCs (0.1 wt %) in HPMC resulted in ∼58% increment in tensile strength, ∼10% increment in modulus, and ∼82% increment in elongation. Moreover, the composite films exhibited high transparency and appreciable water barrier properties that allow their potential application as barrier and transparent films for various applications.
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BIORESOURCE TECHNOLOGY
·
2019
·
IF 6.669
Jianyun Gan,Ya Peng,Qin Chen,Gang Hu,Qinqin Xu,Longming Jin,Haibo Xie
To overcoming the natural recalcitrance of cellulose for glucose production via enzymatic hydrolysis, a new strategy of destroying hydrogen bond donor to reconstruct cellulose’s hydrogen bonding network was developed via a mild reversible reaction of cellulose with CO 2 catalyzed by organic bases. The reaction dynamics of cellulose with CO 2 in the presence of organic bases was studied by using in situ IR. Investigation also included how the organic bases in pretreatment media and pretreatment parameters including CO 2 pressure, pretreatment temperature and time affected the physical-chemical structure of cellulose by Fourier Transform Infrared Spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and Atomic force microscopy (AFM) and subsequent enzymatic scarification of cellulose. The findings showed that dissolution activation efficiency significantly correlated to various parameters, that can be optimized to be the tetramethyl guanidine (TMG)/CO 2 /DMSO solvent system at 50 °C, 2 MPa of CO 2 for 2 h, by which a complete transformation the cellulose crystalline structure from I to II, and 100% glucose yield were achieved. The recyclability and usability are also investigated.
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PubMed
高影响因子
Coatings
·
2019
·Vol. 9
·期 10
·618
·
IF 2.33
Hailong Zhang,Junlei Tang,Hongchang Han,Shengwei Zhang,Hu Wang,Yingying Wang,Tian Li,Bing Lin
In this paper, ethyl cellulose, thermoplastic polyurethane, and mineral oil were used as the main raw materials to synthesize a recyclable thermoplastic gel for anticorrosion coatings by a hot melt method. In addition, the effect of thermoplastic polyurethane on the properties of the coating was discussed. The structure and corrosion protection properties of the coating were characterized and analyzed by a scanning electron microscope, transmission electron microscope, X-Ray diffraction, infrared spectroscopy, dynamic mechanical analysis, salt spray test, and electrochemical measurements. The results show that the ethyl cellulose and oil in the coating can form a stable organic-gel structure by hydrogen bonding, and the mineral oil and castor oil are uniformly dispersed in the coating. The surface of the coating does not change after 3000 h of a salt spray test. During the repeated hot melting spraying and immersion in 3.5 wt.% NaCl solution for five times, the electrochemical impedance modulus of the coating was always above 109Ω⋅cm2, the water absorption rate was always less than 1.5 wt.%, and the mechanical properties of the coating did not decrease. This novel coating could be used for the corrosion protection of flange and valve connections in pipeline and bolting connections in different industries. The disassembly and assembly operation of these connection structures during the regular maintenance will destroy the ordinary anticorrosion coating, and the irregular geometric shape of such places also make difficulties for the preparation of ordinary coatings onsite.Keywords:thermoplastic;ethyl cellulose;anticorrosion coating;recyclable gel;corrosion resistance
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2020
·
IF 10.652
Huiqiang Wang,Jiachen Li,Ning Ding,Xianhai Zeng,Xing Tang,Yong Sun,Tingzhou Lei,Lu Lin
The eco-friendly sodium carboxymethylcellulose (CMC-Na)/polyvinyl alcohol (PVA) hydrogel reinforced with cellulose nanocrystal (CNC) and graphitic-like carbon nitride (g-C 3 N 4 ) was firstly prepared as smart adsorption hydrogel with mechanical, thermal and swelling response. Encouragingly, the mechanical properties of the g-C 3 N 4 /CNCs-H hydrogel were enhanced with simply changing the content of g-C 3 N 4 . The 1.0% g-C 3 N 4 /CNCs-H hydrogel had outstanding tensile strength (up to 648 KPa), excellent elongation (1169%) and satisfactory toughness (340 KJ/m 3 ). These enhancements were due to the inherently superior properties of the prepared CMC-Na/PVA and the synergistic effect of strong hydrogen bonding interactions between g-C 3 N 4 , CNCs and CMC-Na/PVA chains. The as-prepared g-C 3 N 4 /CNCs-H hydrogel has high equilibrium swelling capacity (90.47–117.3 g/g), which greatly improved the adsorption capacity of methylene blue (MB, q e > 198.6 mg/g). The adsorption properties of MB on the as-prepared hydrogel fitted well with the pseudo-second-order kinetic model and the Langmuir isotherm model. It was showed that the interaction of π-π stacking and hydrogen bonds resulted in the high adsorption capacity of the hydrogels. This study presented a basis and demonstration for the application of hydrogels in contaminants removal in poisonous waterbodies.
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高影响因子
Materials Research Express
·
2019
·Vol. 6
·期 11
·1150b7
·
IF 1.449
Tariq Aziz,Hong Fan,Xiangwei Zhang,Farman Ullah Khan
In this study we have explored the adhesive properties of the modified epoxy resin. The modified epoxy resin was prepared by mixing cellulose nano-crystals (CNCs) and calcium sulfate fillers (CaSO4 fillers) with epoxy resin via sonication technique. The successful synthesis of the modified epoxy resin was characterized by infra-red transformed (FT-IR) spectroscopy. The characteristics peaks appeared at 880 cm−1 and 1052 cm−1 were assigned to –CH bending and –Si–O–C bending vibration. The appearance of these peaks confirmed the successful synthesis of the modified epoxy resin. The surface morphology, size and shape of CNCs, CaSO4 fillers and modified epoxy resin were examined by atomic force microscope (AFM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The thermal stability of the CNCs, CaSO4 fillers and modified epoxy resin was investigated by thermal gravimetric analysis (TGA). The thermal decomposition for the modified epoxy resin was occurred at 370 °C. The adhesive properties including tensile modulus, strength and elongation at break of CNCs, CaSO4 fillers and modified epoxy resin were determined by using universal material testing machine. The obtained results showed remarkable improvement in the adhesive properties of the modified epoxy resin.
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高影响因子
CARBOHYDRATE POLYMERS
·
2019
·
IF 6.044
Tao Hu,Qiang Liu,Qinze Liu,Yang Wu,Congde Qiao,Jinshui Yao
Green composite adsorbent with low cost and high efficiency towards toxic Cr(VI) removal from the polluted water has a broad application prospect. In this work, a mussel-inspired Cr-adsorbent namely poly(catechol tetraethylenepentamine-p-phenylenediamine)@as-prepared cellulose (PAC@AC) is successful fabricated via catechol-amine copolymer adhering onto as-prepared cellulose (AC). The detailed characterizations of product are run with SEM, FT-IR, TGA , XRD, EDS and XPS analysis. Many factors are investigated to affect the adsorption of Cr(VI) by PCA@AC, including ratio of AC to PCA, adsorbent dosage, contact time, initial Cr(VI) concentration, pH, temperature and exterior ions. The maximum adsorption capacity of PCA@AC for Cr (VI) is obtained by 507.61 mg/g at 30°C using Langmuir model, which is very higher than the pure AC. The removal ability of PCA@AC is ascribed to the electrostatic interaction and reduction reaction of Cr(VI) to Cr(III) during the adsorption process. In addition, the adsorption process is spontaneous and endothermic, not require any external energy. The composite adsorbent (PCA@AC) has great potential for Cr(VI)-wastewater purification with an excellent chelating ability.
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高影响因子
Journal of Materials Chemistry A
·
2019
·Vol. 7
·期 19
·11742-11755
·
IF 10.733
Zhiming Li,Hua Tian,Yanyan Yuan,Xueqiong Yin,Xin Wei,Liwen Tang,Suying Wei
In this study, a novel gradient heating procedure was developed to fabricate the targeted metal-ion-imprinted thermo-responsive material, i.e. ion-imprinted thermo-responsive BC derivative (ITB), from bacterial cellulose using Cu2+ as a template and N-isopropylacrylamide (NIPAM) as a monomer; moreover, the structure and properties of ITB were analysed via various analytical techniques including FTIR spectroscopy, DSC, SEM, and Raman spectroscopy. The lower critical solution temperature (LCST) of ITB was 38.57 °C in the heating procedure, whereas it was 30.81 °C in the cooling procedure. The adsorption capacity of ITB for Cu2+ reached 95.20 mg g−1 at 45 °C (>LCST), the desorption rate was 98.81%, and desorption could be simply achieved by washing the adsorbents with water at 20 °C (
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2019
·
IF 4.784
Hafiz Muhammad Ahsan,Xingzhong Zhang,Yan Li,Bin Li,Shilin Liu
The phenomenon of polymer adsorption was applied to modify the surface of microcrystalline cellulose (MCC). The active polymer sodium carboxymethyl cellulose (CMCNa), having different molecular weight was used to produce modified MCCs. The average particle size of unmodified MCC was about 14.208 ± 0.064 μm, and it was increased to 19.576 ± 0.26 μm after modification. The modified MCCs exhibited a typical shear thinning behavior. It suggested that the molecular weight of active polymer had an amenable and significant influence on the physicochemical properties and stability of MCCs. The composites prepared from CMCNa with high molecular weight were more stable than others. Moreover, dried MCCs could be re-dispersed in water and could be used as a stabilizer for Pickering emulsions. The obtained emulsions (CMCNa-c) showed higher stability against pH changes, ionic strength and coalescence during storage. It suggested that the re-dispersible MCCs played a significant role in stabilization of emulsions. Furthermore, the re-dispersible MCCs preserved the original properties of un-dried composites and could also be used in other food allied sectors.
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高影响因子
危险品化学品经营许可证（带存储）