Ramie Stalk Research Articles

Bending mechanics test and parameters calibration of ramie stalks

Research and development of ramie harvesting equipment is a key link to revitalize ramie industry, problems such as the tendency of stalks to tangle and clog the machine are very problematic, seriously affect the quality and fluency of the harvester. The structure of ramie stalk is complex, and the mechanical properties of each component vary greatly, collision between stalk and machine creates complex stress relationship. By building a finite element model, it is possible to analyze the stress state of the stalk during bending from a microscopic perspective, and to analyze the complex stress–strain situation within the stalk. The purpose of this paper is to establish a standard ramie stalk bending finite element model to provide a theoretical basis for the subsequent kinematics and dynamics. Firstly, material experiments were carried out on ramie straw. The structural and mechanical parameters of the straw components were obtained through measurement and calculation tests, and the force–deformation curves for straw bending were obtained. Bending finite element simulations were carried out on the basis of mechanical tests, and the parameters such as dynamic friction coefficient, wood Poisson's ratio and bast Poisson's ratio were determined by the central combination design. Then established an accurate bending finite element simulation model of ramie stalk, the accuracy of the model was verified at the end. In this paper, the key parameters of the ramie stalk model were calibrated through a combination of material tests and simulations. All parameters of the ramie stalk model were finally obtained, and the bending mechanical properties of the ramie stalk were analysed by applying finite element analysis. This bending mechanics simulation model can be used for kinematic and dynamics simulation analysis of conveying and baling to provide a theoretical basis for the structural design of the harvester. The methods explored here can be applied to other slender straw crops.

Calibration of Ramie Stalk Contact Parameters Based on the Discrete Element Method

To obtain the physical parameters and contact parameters of ramie stalk decorticating simulation, the structural dimensions, density, moisture content, elastic modulus, and contact parameters of the ramie stalk were measured in this study based on the phloem and xylem of the ramie stalk. The physical stacking angles of the phloem and xylem were measured by the cylinder lift method and the extraction of the partition method, respectively. The contact parameters between the xylem and phloem of the ramie stalk were directly calibrated. Additionally, the contact parameters of the phloem–phloem, phloem–Q235A steel, xylem–xylem, and xylem–Q235A steel were used as calibration objects, and the simulated stacking angle was used as the evaluation index. Then, the Plackett–Burman test was designed to screen for the parameters which were significantly affecting the simulated stacking angle. Furthermore, the steepest ascent test determined the optimal range of values for two significant parameters of the phloem and three significant parameters of the xylem. Based on the central composite design, the second-order regression equations between the significant parameters of the phloem and xylem and the stacking angle were established, respectively. The physical stacking angles of 37.93° for phloem and 27.17° for xylem were the target values to obtain the optimal parameter group. The results showed that the restitution, static, and rolling friction coefficients between the xylem and phloem were 0.60, 0.53, and 0.021, respectively. The static and rolling friction coefficients between the phloem and phloem were 0.41 and 0.056, respectively. The rolling friction coefficient between the xylem and Q235A steel was 0.033, and the static and rolling friction coefficients between the xylem and xylem were 0.44 and 0.016, respectively. The verification test showed that the relative error values were less than 2.11%, which further indicated that the modeling method and parameter calibration of the ramie stalk phloem and xylem models were accurate and reliable. They can be used for the subsequent calibration simulation tests of ramie stalk bonding parameters and ramie stalk decorticating simulations.

Phosphate-functionalized ramie stalk adsorbent for efficient removal of Zn2+ from water: adsorption performance, mechanism, and fixed-bed column treatment of real wastewater.

A highly efficient adsorbent functionalized with phosphate groups made from a local agricultural waste, ramie stalk, was designed for Zn2+ removal from water. SEM, EDS, FTIR, zeta potential, and XPS tests were used to study the morphology and properties of modified ramie stalk (RS-P). The results showed that the phosphate groups were successfully grafted to the surface of the ramie stalk, which has a multilayered and porous structure and can provide large adsorption sites. Adsorption performance and mechanism were investigated in the static and dynamic adsorption experiments. The adsorption kinetics of Zn2+ by RS-P were better fitted by the pseudo-second-order model, indicating chemical adsorption. Adsorption isotherm was better described by Redlich-Peterson isotherm, which suggested heterogeneous and multi-site adsorption, with a maximum adsorption capacity of 0.558mmolg-1. The characterization of adsorbents before and after adsorption indicated that a combined action of electrostatic interaction and ion exchange was the primary mechanism of adsorption. Dynamic adsorption experiments with fixed-bed column displayed excellent water treatment capabilities. RS-P exhibited good reusability in 5 cycles without much deterioration in its adsorption performances. Complex co-existing ions impaired Zn2+ adsorption during real wastewater treatment. This research benefits agricultural waste recycling and provides safe water to ensure economic, social, and environmental sustainability.

Phytoremediation plants (ramie) and steel smelting wastes for calcium silicate coated-nZVI/biochar production: Environmental risk assessment and efficient As(V) removal mechanisms

Arsenic is one of the most common and harmful pollutants in environment throughout the world, especially in aqueous solutions. In this study, two kinds of industrial solid wastes (Oxide scale (OS) and Blast furnace slag (BFS)) and one kind of phytoremediation plant waste (Ramie stalk) were used to prepare an environmentally friendly, low-cost, and efficient calcium silicate coated nano zero-valent iron (nZVI)/biochar composite (BOS) for As(V) adsorption. The potential environmental risks of BOS and their effects on removal of arsenic ions from aqueous media were investigated. The adsorption mechanism was explored and discussed based on XRD, SEM-EDS, XPS, etc. The results suggested that the environmental risk and heavy metals toxicity in BOS by co-pyrolysis were significantly reduced compared to the original materials, and no additional contaminant was observed in the subsequent experiments. Simultaneously, the BOS showed excellent As(V) removal capacity (>99%) and regenerative properties. The As(V) removal mechanisms are mainly ascribed to the complexation and co-precipitation between Fe and As, and the hydrogen bond between CO functional group of BOS and As. The mechanism of enhanced nZVI activity for As(V) removal was revealed. A protective layer of Ca2SiO4 was formed on the surface of nZVI during the co-pyrolysis process to prevent the passivation of nZVI. During the reaction process, the Ca2SiO4 covering the nZVI surface would be continuously detached to expose the fresh surface of nZVI, thus providing more redox activity and adsorption sites. This study provides a new way to treat and recycle industrial steel solid wastes and phytoremediation plant wastes, and the produced calcium silicate coated-nZVI/biochar composite is proposed to be a very promising material for practical remediation of As(V)-contaminated water bodies.

Optimization and Test of Structural Parameters of Flat Hob Chopper

In order to reduce the chopping power consumption of a flat hob chopper (referred to herein as chopper) on the premise of ensuring the chopping effect of the chopper, the mathematical model of optimal design of chopper is established in this paper with the minimum chopping power as the objective. With the help of MATLAB software, the mathematical model is solved. The chopping power curves of each point on the chopper blade edge line before and after the optimization of structural parameters are generated. The results indicate that when the coordinate value of point A on the blade edge line on the Z axis is 0.7 m; the included angle between the bottom surface of the blade and the axis of the cutter roll is 6°. When the radius of the chopper is 0.11 m, the chopper can obtain the theoretical minimum chopping power. The analysis result of chopping power curve is the chopping power after structural parameter optimization is reduced by about 25.50% compared with that before optimization. The choppers before and after the optimization of structural parameters was trial manufactured and sequentially mounted on the performance test bench of the chopping system of the forage ramie harvester. The test results show the standard-length rate of ramie stalk chopped by the choppers before and after the optimization of structural parameters were 92.96% and 92.84%, respectively, which were extremely close to each other, indicating that the optimization of structural parameters has no influence on the chopping effect of the chopper. The chopping power of the chopper is reduced by 22.25% after optimization, which is close to the software analysis value (25.50%), indicating that the optimization result is accurate and reliable. This study can provide parameter foundation and an optimization method for lowering chopping power consumption of the chopper.

Facile synthesis of triazole and carboxyl-functionalized cellulose-based adsorbent via click chemistry strategy for efficient Gd(III) removal

Gd(III) containing wastewater has toxic effects on both public health and aquatic life. However, few literature is available using wastes biomass containing cellulose with enough high adsorption capacity to remove Gd(III). Herein, we described a facile synthesis of triazole and carboxyl- functionalized magnetic cellulose-based material from ramie stalk (TCM-RS) through click chemistry strategy for the first time. The synthesized sample (TCM-RS) was used as an efficient adsorbent for the removal of Gd(III) from aqueous solution. The obtained materials were well characterized. Batch adsorption experiments showed that the combination of bifunctional chelating ligand, sufficient specific surface area, and magnetic response endowed the adsorbent with excellent adsorption selectivity, high adsorption capacity and easy separation of adsorbent from solutions, respectively. The maximum Gd(III) uptake of TCM-RS (62.8 mg/g) was reached within 40 min. Adsorption isotherms and kinetics revealed that the Langmuir model and the pseudo-second-order kinetics model could well describe the adsorption process of Gd(III) onto TCM-RS. Moreover, the sorbent can be regenerated and reused for five cycles without significant loss in adsorption capacity. Our study not only provides new insights into the fabrication of TCM-RS through click chemistry strategy, but also reveal that TCM-RS has great potential application for the removal of Gd(III) from wastewater.

An amino-functionalized ramie stalk-based adsorbent for highly effective Cu2+ removal from water: Adsorption performance and mechanism

Abstract This study reports a potential application of a local agricultural waste, ramie stalk, as a raw material to design a highly effective adsorbent by chemical modification with tetraethylenepentamine for Cu2+ removal from water. Surface morphology and chemical structure, elements components and physicochemical properties of the adsorbent were characterized by using SEM, EDX, FTIR, Zeta potential Meter and XPS. After modification, the amine groups were successfully grafted onto the surface of ramie stalk, which have multilayered and porous structures. A batch and fixed-bed column method were used to investigate the adsorption performance and mechanism of Cu2+. The optimum pH for Cu2+ adsorption was found to be 5. In the batch adsorption experiment, the data of the kinetic experiment were better fitted by the pseudo-second-order model (R2 = 0.9917), indicating that the adsorption of Cu2+ by modified Ramie stalk was mainly controlled by chemical adsorption. The adsorption equilibrium isotherm could be better described by Langmuir model (R2 = 0.9929) which suggested a monolayer sorption and the maximum adsorption capacity was 0.587 mmol g−1. In the dynamic adsorption experiment, the operation conditions, such as flow rate, initial concentration, and bed height were evaluated. The experiments results showed that with the higher initial concentration and the lower bed height, the adsorption capacity of the adsorbent increased and the fixed-bed column displayed good capacity for treating water under dynamic condition. The coordination bonding between Cu2+ and amine groups on the modified ramie stalk is the main adsorption mechanism. The new type adsorbent exhibited good reusability for 5 cycles without deterioration in its adsorption performances. Ramie stalk could be utilized effectively as an efficient adsorbent for treatment of the copper contaminated water environment.

Test and Analysis on Axial Compressive Mechanics of Ramie Stalk

Test and Analysis on Axial Compressive Mechanics of Ramie Stalk

Biodegradation of ramie stalk by Flammulina velutipes: mushroom production and substrate utilization

In the textile industry, ramie stalk is byproducts with a low economic value. The potential use of this leftover as a substrate ingredient for Flammulina velutipes (F. velutipe) cultivation was evaluated. The degradation and utilization of ramie stalk by F. velutipes was evaluated through mushroom production, lignocelluloses degradation and lignocellulolytic enzymes activity. The best substrate mixture for F. velutipes cultivation comprised 50% ramie stalk, 20% cottonseed hulls, 25% wheat bran, 4% cornstarch and 2% CaCO3. The highest biological efficiency of fruiting bodies was reached 119.7%. F. velutipes appears to degrade 12.7–32.0% lignin, 14.4–30.2% cellulose and 9.3–25.7% hemicellulose during cultivation on the different substrates. The results of enzymes activities showed that laccase and peroxidase were higher before fruiting; while cellulase and hemicellulase showed higher activities after fruiting. The biological efficiency of fruiting bodies was positively correlated with the activities of cellulase, hemicellulase and ligninolytic enzyme. The results of this study demonstrate that ramie stalk can be used as an effective supplement for increasing mushroom yield in F. velutipes.

Secretome analysis of Pleurotus eryngii reveals enzymatic composition for ramie stalk degradation.

Pleurotus eryngii (P. eryngii) can secrete large amount of hydrolytic and oxidative enzymes to degrade lignocellulosic biomass. In spite of several researches on the individual lignolytic enzymes, a direct deconstruction of lignocellulose by enzyme mixture is not yet possible. Identifying more high-performance enzymes or enzyme complexes will lead to efficient in vitro lignocelluloses degradation. In this report, secretomic analysis was used to search for the new or interesting enzymes for lignocellulose degradation. Besides, the utilization ability of P. eryngii to ramie stalk substrate was evaluated from the degradation of cellulose, hemicellulose, and lignin in medium and six extracellular enzymes activities during different growth stages were discussed. The results showed that a high biological efficiency of 71% was obtained; cellulose, hemicelluloses, and lignin decomposition rates of P. eryngii were 29.2, 26.0, and 51.2%, respectively. Enzyme activity showed that carboxymethyl cellulase, xylanase, laccase, and peroxidase activity peaks appeared at the primordial initiation stage. In addition, we profiled a global view of the secretome of P. eryngii cultivated in ramie stalk media to understand the mechanism behind lignocellulosic biomass hydrolysis. Eighty-seven nonredundant proteins were identified and a diverse group of enzymes, including cellulases, hemicellulases, pectinase, ligninase, protease, peptidases, and phosphatase implicated in lignocellulose degradation were found. In conclusion, the information in this report will be helpful to better understand the lignocelluloses degradation mechanisms of P. eryngii.

Mechanism of the Adsorption Process: Cu2+ Adsorpted by Ramie Stalk

AbstractAgriculture wastes, ramie stalk, was used to adsorb Cu2+ ion from the aqueous solutions. Adsorption behaviors and mechanism involved in were systematically explored and discussed. A better fitting result of adsorption isotherms of Cu2+ to ramie stalk was obtained from the Langmuir model. This suggested the surface of ramie stalk is rather homogeneous, which is supported by a better fitting result of the adsorption kinetic by using a pseudo‐first‐order kinetic model. Following surface complexation modeling suggested Cu2+ uptake is driven by water‐associated adsorption along with the precipitated CuO species. This is attributed to the low dissociation constant of ramie stalk and thus there was only around one quarter of sur‐ face adsorption sites participating Cu2+ uptake at acidic environment.

Nitrogen removal of ramie stalk treated by acid wastewater combined with Clostridium thermocellum and the kinetic study of pyrolysis

A pretreatment was developed to remove nitrogen from ramie residue and cotton stalk to eliminate potential nitrogen pollutants in biomass energy production. In the pretreatment, straw was treated with acid wastewater from bioleaching for 3h followed by Clostridium thermocellum incubation for 2h. Most nitrogen was removed from biomass waste and the major was that in protein. Pyrolysis process revealed most hemicellulose was removed and the kinetics fitted the first-order equation well. Apparent activation energy of ramie residue increased a little and mass loss became concentrated. Ultimate analysis and pyrolysis analysis revealed the treatment did not weaken the application value of biomass in energy production. Replacing acid wastewater with sulphuric acid, a higher nitrogen removal could be achieved; however, activation energy increased sharply.

Composição química das folhas e dimensões das fibras lenhosas em rami

Objetivando avaliar o potencial de aproveitamento das plantas de rami (Boehmeria nivea Gaud.), após a extração das fibras liberianas (têxteis), determinou-se a composição química das folhas, visando a seu aproveitamento na alimentação animal, e as dimensões das fibras lenhosas do caule, como matéria-prima celulósica. As folhas apresentaram na matéria seca 19,59% de proteína bruta, 12,98% de fibras, 43,10% de carboidratos, 5,23% de extrato etéreo, 19,10% de cinzas, 0,17% de fósforo, 0,038% de ferro, 6,24% de cálcio e 0,59% de magnésio. Esses dados qualificam as folhas para use na alimentação animal como parte de rações balanceadas. As fibras lenhosas do caule apresentaram comprimento de 0,57mm, diâmetro do lúmen de 11,85µm, espessura da parede celular de 5,92µm e largura de 23,7µm. São fibras extremamente curtas, com baixo potencial de utilização para produção de matéria-prima celulósica, podendo ser empregadas em mistura com fibras mais longas ou na produção de raiom, onde essas dimensões não são importantes.

Variação de algumas características de diversas regiões do caule de rami

Com o propósito de encontrar um método mais fácil de determinar algumas características do caule de rami, como peso de caule verde e seco, peso de fibra seca, teor de fibra sobre peso de caule verde e seco, fineza e comprimento de fibra, foram estudadas seis regiões de igual comprimento do caule da variedade "murakami" (Boehmeria nivea Gaud.). As regiões do caule apresentaram valores diferentes com relação às características estudadas. Algumas delas tiveram médias que podem representar as do caule tomado por inteiro.