SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Minwen Jiang,Na Niu,Ligang Chen
A super-adsorbent bentonite-doped lignin hydrogel spheres (LHS-BT) were synthesized in 2 min via a simple template method to remove cationic dyes in wastewater. In this process, acrylic acid (AA) and 2-acrylamido-2-methyl-propanesulfonic acid (AMPS) are grafted onto lignosulfonate through free radical reaction to construct polymer cross-linking network and enhance the adsorption capacity of lignin. Moreover, polyethersulfone was designed as a template to protect the internal crosslinking and maintain the spherical shape. Then, the template shell was ingeniously removed through heat shrinkage. The shell separation and drying process was completed in one step, reducing the post-processing process. A series of characterization methods were used to evaluate the structural characteristics of LHS-BT. The influences of dye concentration, initial pH value, temperature and contact time on adsorption procedure were systematically studied. The adsorption kinetics and equilibrium adsorption isotherms are in accordance with the pseudo-second-order kinetic model and Langmuir isotherm model, respectively. Adsorption experiments showed that LHS-BT have ultra-high adsorption capacity (2541.76 mg/g for malachite green, 1284.46 mg/g for methylene blue and 1047.72 mg/g for rhodamine B) and faster adsorption rate within 85 min. Additionally, LHS-BT exhibited excellent recyclability without significant efficiency loss for at least five cycles. The mechanism of dyes molecular capture onto LHS-BT might be principally ascribed to electrostatic attraction, π-π interaction and hydrogen bonding. Thus, LHS-BT exhibits great potential for used in efficient, environmental, and economical wastewater remediation. Lastly, it is proved that LHS-BT is suitable for adsorption column to quickly purify wastewater containing dyes.
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高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2021
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IF 3.764
Juanhua Kong,Lixia Li,Qiang Zeng,Jinxing Long,Hongyan He,Yingying Wang,Sijie Liu,Xuehui Li
In order to meet the requirements of sustainable development, the production of aromatic compounds from renewable biomass is of great concern. Herein, a surfactant-free microemulsion (SFME) system composed of n-octane, 2-propanol, and water was explored for the depolymerization of lignin though a hydrogen transfer reaction of 2-propanol with acidic ionic liquids (ILs) as catalysts. Experimental results show that the phenol monomer yield from bagasse lignin in the SFME system is at least 4 times higher than that in its corresponding water-free binary system, together with a high selectivity for 4-ethylphenol of 67.8%. In particular, the results also reveal that the controllable polarity and large surface area of the SFME and the aggregation of lignin at the SFME surface are key factors in response to the enhanced yields of phenolic monomers through intensive characterizations. Mechanism studies imply that this system tailors mainly the esterified p-coumarate unit in lignin, and 4-ethylphenol is produced by a cascade reaction, involving hydrolysis, decarboxylation, and hydrogenation. Furthermore, this SFME system also exhibits excellent performance for the depolymerization of other herbaceous lignins, yielding 128.1 mg g–1 phenolic monomers with 59.1% 4-ethylphenol selectivity for corncob lignin. It is thus believed that the process intensification by microemulsion can significantly demonstrate unprecedented potential to accomplish highly efficient lignin conversion.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Ruixia Liu,Tingting Ding,Pingping Deng,Xiaofan Yan,Fuquan Xiong,Jienan Chen,Zhiping Wu
To expand the field of high-value utilization of lignin. The degraded deep eutectic solvent lignin-grafted poly (N-Vinyl caprolactam) (DES-lignin-g-PNVCL) was synthesized by modified DES-lignin and NVCL via the combination of activators regenerated by electron transfer-atom transfer radical polymerization (ARGET-ATRP). Fourier transform infrared spectroscopy (FT-IR), 1 H NMR, X-ray electron spectroscopy (XPS), dynamic light scattering (DLS), differential scanning calorimeter (DSC) were used to characterize the structure and performance of DES-lignin-g-PNVCL. The results indicated that the PNVCL and DES-lignin-g-PNVCL were successfully prepared by ARGET-ATRP. The lowest critical solution temperature (LCST) of PNVCL was 35.75 °C. Due to different strength of hydrogen bond , different energies were required, so the LCST of the polymer can be regulated. When the molar ratio of phenolic hydroxyl group in degraded DES-lignin to 2-bromoisobutyryl bromide (BiBB) was increased from 1:1 to 1:7, the grafting rate of DES-lignin-Br was increased from 32.87% to 60.84%, and the LCST of DES-lignin-g-PNVCL was decreased from 47.98 °C to 27.88 °C. The LCST of DES-lignin-g-PNVCL was increased from 30.98 °C to 44.64 °C when the addition amount of DES-lignin-Br was increased from 20 mg to 200 mg. The LCST of DES-lignin-g-PNVCL was increased from 27.20 °C to 39.86 °C when the ratio of DMF/water was increased from 1:4 to 4:1. The LCST of DES-lignin-g-PNVCL was decreased from 52.10 °C to 31.02 °C when the concentration of DES-lignin-g-PNVCL was increased from 0.5 mg/mL to 2.5 mg/mL. The equation represented the relationship between LCST and influencing factors was obtained, the good predictability provided a tactics for preparing desired LCST thermo-responsible polymer.
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高影响因子
Reaction Kinetics Mechanisms and Catalysis
·
2021
·Vol. 133
·期 1
·371-382
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IF 2.081
Song Wenjing,Song Mengxue,Jiang Xingmao,Yi Xiaodong,Lai Weikun
Hydrolytic cleavage of C–O bond was systematically studied in acidic/alkaline aqueous solution. For phenethoxybenzene (PEB) hydrolysis, 2-phenylethanol and phenol were formed as main products in AlCl 3 solutions, whereas styrene was preferred with Na 2 CO 3 . After a quantitative evaluation of the kinetics of elementary steps, it was concluded that both AlCl 3 and Na 2 CO 3 promoted protons assisted C–O bond scission in H 2 O, whereas alkaline enhanced the dehydration of produced 2-phenylethanol. Kinetic and isotope labeling experiments demonstrated that the hydrolytic rates of PEB were first order with respect to substrate concentrations, hydrolytic cleavage of C–O bond was rate-determining step. The study shed light on the promotional effects and hydrolytic mechanism over acid/base-catalyzed lignin depolymerization in water. Graphic abstract
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Xiaoxiao Wei,Yi Liu,Yadan Luo,Zheng Shen,Shuangfei Wang,Mingfu Li,Liming Zhang
In this study, three lignin fractions F1, F2, and F3 were obtained from eucalyptus kraft lignin (EKL) by solvent extraction with ethyl acetate, acetone, and acetone/water. The antioxidant activity of these lignin fractions were measured and evaluated by using the DPPH radical scavenging activity, ABTS radical cation scavenging activity and ferric reducing antioxidant power analysis. These lignin fractions were also characterized by applying Gel permeation chromatography , Fourier transform infrared, 31 P NMR and 2D HSQC NMR techniques. The three different lignin fractions had rather different average molecular sizes, as well as different phenolic and methoxy functional contents. The ethyl acetate fraction (F1) with the lowest average molecular weight (2342 g/mol) and the highest phenolic hydroxyl content (4.2457 mmol/g) and methoxy groups (6.2714 mmol/g) showed high homogeneity and the highest antioxidant activity. Its DPPH scavenging activity, ABTS + scavenging activity, and ferric reducing the antioxidant power were 68.67%, 75.57%, and 91.89 μmol/g, respectively. Moreover, the antioxidant activity of F1 and F2 was found to be higher than that of butylated hydroxytoluene. Therefore, solvent extraction was shown to be an effective way to separate lignin fractions with high homogeneity, high antioxidant activity, which could lead to application of lignin with higher value.
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高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2021
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IF 6.953
Haixu Wang,Dongjie Yang,Wenlong Xiong,Weifeng Liu,Xueqing Qiu
Nano silica (SiO 2 ) is usually used as a common reinforcing agent in polymer materials, in which the interfacial interaction greatly affects the mechanical properties of the composites. The reinforcement effect of silica on non-polar polymer is restricted due to their poor compatibility. In this work, amphipathic lignin modified by quaternization and alkylation was used as a modifier for silica to prepare hydrophobic lignin/SiO 2 nanoparticles by in-situ one-pot co-precipitation method. In alkaline solution, hydrophobic lignin and SiO 2 (from Na 2 SiO 3 ) were self-assembled to form nanospheres through electrostatic and hydrophobic interactions. The results showed that the lignin/SiO 2 nanoparticles were highly hydrophobic nanospheres with macropores in the surface. When the lignin/SiO 2 nanoparticles (10 wt%) were added to reinforce high-density polyethylene (HDPE), the mechanical properties of HDPE were improved with the strength of 24.5 MPa and the elongation of 1096%, which were increased by 10.4% and 14.3% compared with the control HDPE, because of the good compatibility and large bonding area. This work puts forward a new solution for the application of lignin in reinforcement of non-polar polymers.
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高影响因子
LANGMUIR
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2021
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IF 3.882
Yingying Chai,Yuefei Wang,Bingqi Li,Wei Qi,Rongxin Su,Zhimin He
In this work, lignin/chitosan nanoparticles (Lig/Chi NPs) with controlled structures were synthesized in a simple and scalable microfluidic system. When the positively charged chitosan and the negatively charged lignin solution were blended in a microreactor, Lig/Chi NPs were rapidly formed via the electrostatic coassembly between the amino groups of chitosan and the carboxyl groups of lignin. The ζ potential changes from negative (−13 mV) to positive (+54.5 mV) for Lig NPs and Lig/Chi NPs, respectively. The scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results demonstrated that Lig/Chi NPs have an average particle size of about 180 nm, which can be used as nanocarriers for drug delivery. The anticancer drug nanoparticles with docetaxel (DTX) and curcumin (CCM) were prepared by coassembly with Lig/Chi NPs in a microreactor, which had good drug loading efficiency, biocompatibility, and can release drugs in response to pH in the weakly acidic environment of the tumor. The drug release amounts in acidic solutions that simulated the tumor microenvironment were 51% (DTX@Lig/Chi NPs) and 50% (CCM@Lig/Chi NPs), respectively, which were better than the release amounts at pH 7.4, and have an obvious killing effect on HeLa cells.
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高影响因子
ACS Sustainable Chemistry & Engineering
·
2020
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IF 7.632
Xiaoqi Wang,Mo Qiu,Richard Lee Smith Jr.,Jirui Yang,Feng Shen,Xinhua Qi
Ferromagnetic Ni-doped lignin-derived ordered mesoporous carbon (Ni@OMC) was synthesized in one pot by evaporation-induced self-assembly (EISA) for use as catalysts. Lignin was used to partially replace phloroglucinol (up to 80%) as the carbon precursor under conditions that allowed ordered mesoporous structures to be perfectly retained and Ni particles to be uniformly dispersed within the material. The as-synthesized Ni@OMC catalysts promoted hydrogenation of furfural, affording furfuryl alcohol (FAL) yields and selectivities as high as 91.0 and 98.6% at 180 °C for a 12 h reaction time in the presence of H2 gas. The Ni@OMC catalyst could be simply separated through application of a magnetic field and was recyclable for at least five cycles. The stability of the Ni@OMC catalyst is attributed to space confinement effects of the carbon skeleton on the doped Ni particles through coordinated interactions between lignin and metal ions (Ni2+). The proposed method allows the synthesis of metal-doped ordered porous carbons from lignin and is green and sustainable.
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MOLECULES
·
2021
·Vol. 26
·期 1
·218
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IF 4.412
Tong Luo,Chao Wang,Xingxiang Ji,Guihua Yang,Jiachuan Chen,Srinivas Janaswamy,Gaojin Lyu
Lignin nanomaterials have wide application prospects in the fields of cosmetics delivery, energy storage, and environmental governance. In this study, we developed a simple and sustainable synthesis approach to produce uniform lignin nanoparticles (LNPs) by dissolving industrial lignin in deep eutectic solvents (DESs) followed by a self-assembling process. LNPs with high yield could be obtained through nanoprecipitation. The LNPs were characterized by dynamic light scattering (DLS), transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and gel permeation chromatography (GPC). Distinct LNPs could be produced by changing the type of DES, lignin sources, pre-dropping lignin concentration, and the pH of the system. Their diameter is in the range of 20–200 nm and they show excellent dispersibility and superior long-term stability. The method of preparing LNPs from lignin–DES with water as an anti-solvent is simple, rapid, and environmentally friendly. The outcome aids to further the advancement of lignin-based nanotechnology.Keywords:lignin;nanoparticles;deep eutectic solvents;nanoprecipitation;size-controlled
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高影响因子
RENEWABLE ENERGY
·
2021
·
IF 8.001
Feng Lin,Yulong Ma,Yonggang Sun,Kanghe Zhao,Tingting Gao,Yingbo Zhu
Due to the inertness and structural complexity of lignin, upgrading lignin to biofuels and fine chemicals still faces great challenges. In this paper, a one-pot method was used to catalyze straw lignin with H-ZSM-5 supported by Ni and Ru bimetals, and the lignin conversion rate reached 88.1%. The yield of monophenol was 19.5%, of which the yield of 4-ethylphenol and 4-ethylguaiacol was 4.9% and 3.8%, respectively. The 2D HSQC NMR analysis confirmed that the Ni–Ru/H-ZSM-5 catalyst had an obvious activity of breaking C β -O bonds before and after the reaction. The result showed that after loading metal Ni and Ru, the Lewis acid of the catalytic system was greatly increased, which caused electron transfer between Ni and Ru. 3Ni-1.5Ru/H-ZSM-5 had the strongest activity due to the largest synergy among Ni, Ru and H-ZSM-5. The synergy was the key factor leading to the cleavage of C–C and C–O bonds in straw lignin and the high-performance catalytic degradation of lignin. Besides, the effect of reaction solvent and hydrogen resource on upgrading lignin to fine chemicals over 3Ni-1.5Ru/HZSM-5 catalyst was also intensively investigated. This research developed a method for the direct conversion of lignin into valuable monophenols.
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INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2020
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IF 3.573
Liangfeng Xiao,Weifeng Liu,Jinhao Huang,Hongming Lou,Xueqing Qiu
The technical enzymatic hydrolysis lignin (EHL) and alkali lignin (AKL) were pretreated via alkaline depolymerization and organic solvent extraction process, respectively. The molecular weight of lignin was lowered and the molecular weight distribution was narrowed, while the content of phenolic hydroxyl group increased after the pretreatment of alkaline depolymerization or solvent extraction. The lignin extracted with ethyl acetate got the lowest molecular weight and highest phenolic hydroxyl group content, showing even better free radical scavenging ability than the commercial Irganox1010. Lignin/SBS elastomer composites were prepared with even dispersion of lignin in the SBS matrix with an average particle size close to 40 nm. It was demonstrated that the alkali lignin extracted with ethyl acetate showed the best improvement on the antioxidant performance of SBS and was comparable to that of Irganox1010 in the SBS elastomer, showing great application potential.
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高影响因子
CARBON
·
2020
·
IF 8.821
Binpeng Zhang,Dongjie Yang,Xueqing Qiu,Yong Qian,Huan Wang,Conghua Yi,Dongqiao Zhang
The application of ZnO nanoparticles as photocatalyst is significantly hampered by limited absorption range for solar spectrum, fast recombination of photogenerated carriers and poor recyclability . The modification with carbon structures has attracted attention as their advantageous performance in photocatalysis . Herein, we first report a lignin-derived flower-like carbon (LFC), which is used to modify ZnO. The resulting composite (ZnO/LFC) is composed of ZnO nanoparticles (∼10 nm) embedded on a flower-like carbon consisting of two-dimensional corrugated nanosheets . Especially, LFC exhibits stable three-dimensional structure and rich oxygen-containing functional groups. So ZnO can be uniformly anchored on the LFC. Composite presents an extended optical absorption and enhanced separation of photogenerated carriers due to the interface electronic interaction between ZnO and LFC. The hierarchical flower-like structure facilitates fast substance transfer and high light-harvesting efficiency. Therefore, ZnO/LFC presented an excellent photocatalytic activity toward degradation of sulfamethazine and hydrogen evolution , which were about 3.0 and 2.1 times that of pure ZnO, respectively. Moreover, the recyclability of composite photocatalyst was also significantly better than pure ZnO. This work not only provides a facile, low-cost and scalable strategy to promote practical application of photocatalyst but also opens new path toward the high-value utilization of industrial lignin.
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