KOREAN JOURNAL OF CHEMICAL ENGINEERING
·
2020
·Vol. 37
·期 5
·776-783
·
IF 2.69
Liu Xinghao,Hu Shuheng,Xu Di,Shao Dadong
Uranium (VI), as a toxic contaminant, is a potential detriment to human health and environmental safety. In this experiment, carboxymethyl cellulose/Ca-rectorite composite material (Ca-REC/CMC) was prepared by crosslinking reaction to remove U(VI) from the liquid. The crystal structure was detected by X-ray diffraction (XRD) and surface structure and morphology of the materials were investigated by scanning electron microscopy (SEM). The surface functional groups of prepared materials were detected by Fourier transform infrared spectroscopy (FT-IR). The adsorption capacity of Ca-REC/CMC improved obviously after being modified by CMC. The adsorption capacity of Ca-REC/CMC was closely related to ionic strength and pH. According to thermodynamic parameter calculation, the adsorption process was endothermic and spontaneous. Adsorption isotherms could be depicted perfectly by the Langmuir model. Ca-REC/CMC maintained stability and regeneration after recycling six times. The adsorption mechanism, including electrostatic interactions and ionic interaction, was investigated by the X-ray photoelectron spectroscopy (XPS). Ca-REC/CMC is considered as remarkable potential material for removing U(VI) from the water environment.
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高影响因子
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
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
CELLULOSE
·
2019
·Vol. 27
·期 4
·2161-2172
·
IF 3.917
Song Wenqi,Zhu Min,Zhu Yanfang,Zhao Yuzhen,Yang Miaoxiu,Miao Zongcheng,Ren Huaping,Ma Qiang,Qian Liwei
An eco-friendly, low-cost, and highly efficient adsorbent based on biomass material, cellulose matrix-supported metal-organic-framework (MOF) hybrid aerogel (ZIF-67@CA), was designed and prepared by in situ growth of ZIF-67 nanoparticles on pre-synthesized chemically crosslinked cellulose aerogel. The chemical structure and surface morphology of as-prepared ZIF-67@CA were characterized by various methods. Analysis results confirmed the successful formation of a densely coated layer of ZIF-67 on the surface of the cellulosic aerogel. Owing to its large specific surface area and electrostatic attraction of ZIF-67 with methyl orange (MO), ZIF-67@CA exhibited high adsorption capacity of up to 617 mg g −1 for MO, which was more than four times higher than that of the pristine cellulose aerogel. Additionally, ZIF-67@CA could selectively separate anionic dye from the dye mixture and maintain 90% adsorptivity even after five cycles of repeated usage. Hence, this work provided a feasible solution and scalable platform for the functional design and rational manufacture of MOF-based cellulose aerogel. Moreover, the versatility of its structural design makes it a promising adsorbent material for wide application range of wastewater treatment.
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ACS Sustainable Chemistry & Engineering
·
2019
·
IF 6.97
Na Li,Jing Ming,Ruchao Yuan,Shuo Fan,Liu Liu,Faxue Li,Xueli Wang,Jianyong Yu,Dequn Wu
A novel schiff base (BD) containing nitrogen and silicone was prepared, and a phosphorus–nitrogen silicone flame retardant (BDD) was synthesized based on BD and 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO). It was found that the structure of BD changed continuously during the heating process and formed a self-cross-linking network structure at about 400 °C, while the porous fluffy shape was formed by BDD as an intumescent flame retardant. The char yields of BD and BDD at 700 °C were 62% and 38% in nitrogen, respectively. The obtained BD and BDD were blended to enhance the flame retardancy of cellulose membranes via a cooperative effect, and the properties were significantly achieved, which can be proved by the limit oxygen index (LOI), cone calorimeter test, and thermogravimetric results. The results showed that the incorporation of 25 wt % BD brought a 29% LOI, and the peak heat release rate (PHRR) was reduced to 732.2 kW/m2, in contrast with an LOI of 18% and PHRR of 1050.1 kW/m2 for pure cellulose. The addition of 25% BDD increased the LOI to 27% and decreased the PHRR to 644.9 kW/m2. The improved flame-retardant performance for cellulose membranes was primarily assigned to the synergistic effect from the physical barriers of self-cross-linking properties in the condensed phase and capturing or dilution of combustible gases by free radicals. This suggested that wielding BD as a self-crossing monomer and applying BDD as an intumescent flame retardant to achieve effective results on fire suppression had great potential for fire-safe cellulose.
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高影响因子
CHEMICAL ENGINEERING JOURNAL
·
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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COMPOSITES SCIENCE AND TECHNOLOGY
·
2020
·
IF 7.094
Yunxiao Liu,Lijuan Zhou,Li Wang,Xiaolong Pan,Kuntao Wang,Jie Shu,Lehuan Liu,Hui Zhang,Leyu Lin,Xinyan Shi,Alois K. Schlarb,Jianming Zhang
Owing to the advantages in storage, transportation and melt-processing, the powder form of cellulose nanocrystals (CNCs) as an attractive biomass filler is highly desired for the industrial application. Herein, by systematically tailoring the reaction conditions, we prepared the air-dried porous powder of CNCs modified with PMMA (CNCs-g-PMMA) via a green synthesis route, that is, using ceric ammonium nitrate (CAN) as an initiator in aqueous medium . Our results show that the porous powder of air-dried CNCs-g-PMMA can be easily obtained when the grafting ratio of PMMA was higher than 70 wt%. CNCs-g-PMMA porous powder demonstrates high specific surface area (47.8 m 2 /g), excellent hydrophobicity and oleophilicity properties. It therefore can be used as a filter for oil/water separation or as a highly efficient absorbing material. Moreover, benefiting from the improved thermal stability of CNCs and melt-processing character of PMMA, the porous powder of CNCs-g-PMMA has been converted to a transparent film by a simple compression molding . The as-prepared film demonstrates extraordinary UV shielding and mechanical stability upon heating. Particularly, there is an extraordinary increase in glass transition temperature of PMMA from 112.6 to 138.6 °C. This research provides a facile and green strategy to fabricate CNCs-g-PMMA porous powder, which shows industrial applications from different perspectives.
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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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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
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
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Jianzhen Wu,Xiuzhicheng Wu,Fujian Yang,Xiaonan Liu,Fanjun Meng,Qinglin Ma,Yuju Che
Building multiple chemical crosslinks is an effective strategy to improve mechanical properties and to diversify final application of polysaccharide nanoparticles reinforced poly(vinyl alcohol) (PVA) physical hydrogels. In this work, PVA/cellulose nanofibers (CNFs) were used as composite substrate to fabricate ionic conductive hydrogels for strain sensor. Three types of characteristic crosslinks, including chemical crosslinking via boronic ester covalent bonds only, and with additional metal coordination bonding, as well as coexistence of physical crosslinks via PVA crystallites and aforementioned two kinds of chemical crosslinks, were constructed. The sample with triple crosslinks has superior mechanical strength and resistance to fatigue, and the polydopamine/Fe 3+ ratio act as key to tune final performance because double-network structure prefers to form as Fe 3+ is superfluous, while dual-crosslink one forms in the case of insufficient Fe 3+ . As-optimized ionic conductive hydrogel is suitable as strain sensor for probing human motions. This work provides an interesting insight into the network structure and property regulation for PVA/CNF composite hydrogels with multiple crosslinks.
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PubMed
高影响因子
危险品化学品经营许可证（带存储）