scholarly journals Characterization of Bio-Adsorbents Produced by Hydrothermal Carbonization of Corn Stover: Application on the Adsorption of Acetic Acid from Aqueous Solutions

Energies ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 8154
Author(s):  
Maria Elizabeth Gemaque Costa ◽  
Fernanda Paula da Costa Assunção ◽  
Tiago Teribele ◽  
Lia Martins Pereira ◽  
Douglas Alberto Rocha de Castro ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Acetic Acid ◽  
Aqueous Solutions ◽  
Carbon Content ◽  
Corn Stover ◽  
Elemental Analysis ◽  
Hydrothermal Carbonization ◽  
Process Temperature ◽  
Sem Images

In this work, the influence of temperature on textural, morphological, and crystalline characterization of bio-adsorbents produced by hydrothermal carbonization (HTC) of corn stover was systematically investigated. HTC was conducted at 175, 200, 225, and 250 °C, 240 min, heating rate of 2.0 °C/min, and biomass-to-H2O proportion of 1:10, using a reactor of 18.927 L. The textural, morphological, crystalline, and elemental characterization of hydro-chars was analyzed by TG/DTG/DTA, SEM, EDX, XRD, BET, and elemental analysis. With increasing process temperature, the carbon content increased and that of oxygen and hydrogen diminished, as indicated by elemental analysis (C, N, H, and S). TG/DTG analysis showed that higher temperatures favor the thermal stability of hydro-chars. The hydro-char obtained at 250 °C presented the highest thermal stability. SEM images of hydro-chars obtained at 175 and 200 °C indicated a rigid and well-organized fiber structure, demonstrating that temperature had almost no effect on the biomass structure. On the other hand, SEM images of hydro-chars obtained at 225 and 250 °C indicated that hydro-char structure consists of agglomerated micro-spheres and heterogeneous structures with nonuniform geometry (fragmentation), indicating that cellulose and hemi-cellulose were decomposed. EDX analysis showed that carbon content of hydro-chars increases and that of oxygen diminish, as process temperature increases. The diffractograms (XRD) identified the occurrence of peaks of higher intensity of graphite (C) as the temperature increased, as well as a decrease of peaks intensity for crystalline cellulose, demonstrating that higher temperatures favor the formation of crystalline-phase graphite (C). The BET analysis showed 4.35 m2/g surface area, pore volume of 0.0186 cm3/g, and average pore width of 17.08 μm. The solid phase product (bio-adsorbent) obtained by hydrothermal processing of corn stover at 250 °C, 240 min, and biomass/H2O proportion of 1:10, was activated chemically with 2.0 M NaOH and 2.0 M HCl solutions to investigate the adsorption of CH3COOH. The influence of initial acetic acid concentrations (1.0, 2.0, 3.0, and 4.0 mg/mL) was investigated. The kinetics of adsorption were investigated at different times (30, 60, 120, 240, 480, and 960 s). The adsorption isotherms showed that chemically activated hydro-chars were able to recover acetic acid from aqueous solutions. In addition, activation of hydro-char with NaOH was more effective than that with HCl.

Effect of L-Arginine on the Carbon Microsphere Forming under Hydrothermal Carbonization

2019 ◽  
Vol 41 (1) ◽  
pp. 72-72
Author(s):  
Jilei Liang Jilei Liang ◽  
Mengmeng Wu Mengmeng Wu ◽  
Hongmei Cai Hongmei Cai ◽  
Hao Wang Hao Wang ◽  
Hua Huang Hua Huang ◽  
...  
Keyword(s):  
Acetic Acid ◽  
Adsorption Capacity ◽  
Surface Property ◽  
Condensation Reaction ◽  
Hydrothermal Carbonization ◽  
Carbon Microspheres ◽  
N2 Adsorption ◽  
Sem Images ◽  
Ft Ir ◽  
Adsorption Desorption

Carbon microspheres (CMs) with a diameter of 5-10 μm have been synthesized by hydrothermal carbonization of starch and L-arginine. The surface property and structure of CMs were examined by FT-IR spectra, N2 adsorption-desorption isotherms and SEM images. These characterizations indicated that the L-arginine does not connect into the CMs but it promotes the starch hydrolysis and polymerization-condensation reaction of intermediate, which accelerates the formation of CMs and improves the yield in shorter time. The surface property of CMs determines adsorption capacity for acetic acid. By contrast, the porosity resulted from the carbonization at 500 and#176;C dominates the adsorption capacity for acetic acid.

scholarly journals Synthesis and Characterization of Hollow-Sphered Poly(N-methyaniline) for Enhanced Electrical Conductivity Based on the Anionic Surfactant Templates and Doping

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1023
Author(s):  
Chatrawee Direksilp ◽  
Anuvat Sirivat
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Doping Level ◽  
Anionic Surfactants ◽  
Sodium Dodecylsulfate ◽  
Sem Images ◽  
Dioctyl Sodium Sulfosuccinate ◽  
Surfactant Templates ◽  
Particle Shapes

Poly(N-methylaniline) (PNMA) is a polyaniline derivative with a methyl substituent on the nitrogen atom. PNMA is of interest owing to its higher solubility in organic solvents when compared to the unsubstituted polyaniline. However, the electrical conductivity of polyaniline derivatives suffers from chemical substitution. PNMA was synthesized via emulsion polymerization using three different anionic surfactants, namely sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and dioctyl sodium sulfosuccinate (AOT). The effects of surfactant structures and concentrations on electrical conductivity, doping level, crystallinity, morphology, and thermal stability were investigated. The re-doping step using perchloric acid (HClO4) as a dopant was sequentially proceeded to enhance electrical conductivity. PNMA synthesized in SDBS at five times its critical micelle concentration (CMC) demonstrated the highest electrical conductivity, doping level, and thermal stability among all surfactants at identical concentrations. Scanning electron microscopy (SEM) images revealed that the PNMA particle shapes and sizes critically depended on the surfactant types and concentrations, and the doping mole ratios in the re-doping step. The highest electrical conductivity of 109.84 ± 20.44 S cm−1 and a doping level of 52.45% were attained at the doping mole ratio of 50:1.

AN EXPERIMENTAL STUDY ON MICROSTRUCTURE OF TUNGSTEN ALLOYS

2019 ◽  
Vol 27 (07) ◽  
pp. 1950169 ◽  
Author(s):  
E. DEMIR ◽  
M. N. MIRZAYEV ◽  
A. B. TUĞRUL ◽  
B. A. ABDURAKHIMOV ◽  
S. İ. KARAASLAN
Keyword(s):  
Thermal Stability ◽  
Weight Loss ◽  
High Temperatures ◽  
Microstructural Characterization ◽  
Sem Images ◽  
Argon Gas ◽  
Gas Desorption ◽  
Gas Atmosphere ◽  
Thermal Stability Of

The aim of this study is to provide information about microstructural and thermal properties of tungsten-based composites. Phase composition and microstructural characterization of tungsten composites were performed using X-ray diffractometer (XRD), Scanning Electron Microscopy (SEM), and Raman Spectroscopy. SEM images revealed the distribution of tungsten (W), vanadium carbide (VC) and graphite (C) powders in the tungsten matrix. The Raman spectra showed two major peaks, which are recorded at 1331 (vs) cm−1, and 1583 (vs) cm−1. These bands can be attributed to disorder graphite (D) and graphite (G). Thermogravimetric analysis (TGA) measurements were performed to determine the weight loss and thermal stability of the tungsten-based composites under argon gas atmosphere and at high temperatures. TGA measurements were performed to determine weight loss and thermal stability of tungsten-based composites under argon gas atmosphere and at high temperatures. The TG curve showed a slight weight loss in this temperature range. Mass loss is thought to be due to oxidation and gas desorption of materials.

Preparation and characterization of natural and synthetic humic acids by thermogravimetry analysis

2020 ◽  
Vol 11 (5) ◽  
pp. 12-20
Author(s):  
Nelson Consolin Filho ◽  
Marcilene Ferrari Barriquello Consolin ◽  
Patrícia Valderrama ◽  
Elisângela Corradini ◽  
Edvani Curti Muniz
Keyword(s):  
Thermal Stability ◽  
Humic Acid ◽  
Alkaline Medium ◽  
Elemental Analysis ◽  
Oxidative Polymerization ◽  
Metallic Ions ◽  
Element Analysis ◽  
Metal Type ◽  
Nitrogen Contents

In this study, a polymer with characteristics analogous to that of the humic acid was obtained through oxidative polymerization in alkaline medium using para-benzoquinone as precursor, and compared to natural humic acid (HA) extracted from a soil. Complexes of as-prepared synthetic humic acid (SHA) with the Cu2+, Fe3+ and Mn2+ ions were also prepared. Elemental analysis and thermogravimetry were used for comparing the SHA characteristics with those of HA and for evaluating the effect of the metal-type for complexing with SH and SHA. Element analysis showed that SHA presented almost the same atomic constitution of HA, except for or sulfur and nitrogen contents, fact that is expected due to the precursor compounds. TGA curves of HA and SHA are quite similar in spite the thermogravimetic index (TGI) indicates higher aromatic portion in SHA. SHA-metallic ions (SHA-Cu2+, SHA-Fe3+ and SHA-Mn2+) complexes presented different thermal stability as compared among them and with the precursor SHA. The data indicate that the complexation is dependent of metallic ion-type and provokes different rearrangements in the SHA matrix.

scholarly journals Physical properties characterization of Natural Protein Fibre Peacock Feather Barbs

2017 ◽  
Author(s):  
Sekhar Das ◽  
Seiko Jose ◽  
Pintu Pandit
Keyword(s):  
Thermal Stability ◽  
Vertical Structure ◽  
Average Length ◽  
X Ray Diffraction ◽  
Colour Intensity ◽  
Sem Images ◽  
X Ray ◽  
Natural Protein ◽  
Mechanical Characterisation

AbstractIn the present study, the barbs of peacock feather were subjected to its physio-mechanical characterisation. Various properties of barbs viz., bundle strength, diameter, moisture regain, thermal stability, X-ray diffraction, colour intensity and FTIR was studied according standard analytical methods. The surface morphology of the barbs was examined using SEM images. The results indicate that the barb is a hollow vertical structure made up of protein. The average length and diameter of the barb was found to be 45 mm and 82 μm respectively. The FTIR study confirms the presence of characteristic peaks for protein, related to the keratinous material. The barbs seem to be semi-crystalline in nature, as indicated by X-ray study.

Synthesıs and Characterızatıon of New Trıazole and Coumarın-Derived Heterocyclıc Compounds Part I

2019 ◽  
Vol 41 (6) ◽  
pp. 1097-1097
Author(s):  
Nurhan G mr k o lu Nurhan G mr k o lu ◽  
Muhammad Imran and Inam Iqbal Muhammad Imran and Inam Iqbal
Keyword(s):  
Acetic Acid ◽  
Elemental Analysis ◽  
13C Nmr ◽  
Heterocyclic Compounds ◽  
Acid Hydrazide ◽  
Triazole Ring ◽  
Basic Medium ◽  
Synthesis And Characterization ◽  
Ethyl Bromoacetate

Synthesis of ethyl ester of acetic acid containing 5-oxo-[1,2,4] triazole ring (2) was achieved by the condensation of 3-substituted-4-amino-1H-1,2,4-triazol-5(4H)-one (1) with ethyl bromoacetate in basic medium. Compound 2, was then further reacted with hydrazine hydrate to form acid hydrazide, which is 2-(4-amino-3-substituted-5-oxo-4,5-dihydro-1H-1,2,4-triazol-1-yl)acetohydrazide (3). Compound 3 was later treated with three different diverse coumarin aldehydes (6, 12, 18) resulted in the formation of arylidene hydrazides as cis–trans conformers (7, 8, 13, 14, 19, 20). In conclusion, we synthesized 1,2,4-triazole Schiff bases derived from the condensation of 3-substituted-4-amino-1,2,4-triazole-5-on and formylhydroxy-4-methylcoumarin derivatives, which have been characterized by, spectroscopic measurements (IR, 1H-NMR, 13C-NMR and elemental analysis).

scholarly journals Synthesis and Characterization of Novel Biginelli Dihydropyrimidinone Derivatives Containing Imidazole Moiety

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Mashooq Ahmad Bhat ◽  
Mohamed A. Al-Omar ◽  
Ahmed M. Naglah ◽  
Atef Kalmouch ◽  
Abdullah Al-Dhfyan
Keyword(s):  
Acetic Acid ◽  
Elemental Analysis ◽  
Efficient Method ◽  
Glacial Acetic Acid ◽  
Solvent Free ◽  
Synthesis And Characterization ◽  
Spectroscopic Methods ◽  
Free Condition ◽  
Solvent Free Condition

Enaminone, (2E)-1-[4-(1H-imidazol-1-yl) phenyl]-4-methylpent-2-en-1-one (II) was synthesized by refluxing 1-[4-(1H-imidazol-1-yl) phenyl] ethan-1-one (I) with dimethylforamide dimethylacetal (DMF–DMA) under solvent-free condition for 12 hours. Finally, the dihydropyrimidinone derivatives containing imidazole moiety (1–15) were obtained by reacting enaminone, (2E)-1-[4-(1H-imidazol-1-yl) phenyl]-4-methylpent-2-en-1-one (II) with urea and different substituted benzaldehydes in the presence of glacial acetic acid. Dihydropyrimidinone derivatives containing imidazole moiety were synthesized in excellent yield by means of a simple and efficient method. All the compounds were confirmed by elemental analysis. The structures of all the compounds were confirmed by modern spectroscopic methods.

scholarly journals Acid hydrolysis of corn stover using hydrochloric acid: Kinetic modeling and statistical optimization

2014 ◽  
Vol 20 (4) ◽  
pp. 531-539 ◽  
Author(s):  
Yong Sun ◽  
Gang Yang ◽  
Zhi-Hua Jia ◽  
Chao Wen ◽  
Lian Zhang
Keyword(s):  
Acetic Acid ◽  
Hydrochloric Acid ◽  
Corn Stover ◽  
Acid Concentration ◽  
Effective Removal ◽  
Pretreatment Temperature ◽  
Predicted Values ◽  
Hydrolysis Of ◽  
Good Agreement

The hydrolysis of corn stover using hydrochloric acid was studied. The kinetic parameters of the mathematical models for predicting the yields of xylose, glucose, furfural and acetic acid were obtained, and the corresponding xylose generation activation energy of 100 kJ/mol was determined. The characterization of corn stover using with different techniques during hydrolysis indicated an effective removal of xylan and the slightly alteration on the structures of cellulose and lignin. A 23five levels Central Composite Design (CCD) was used to develop a statistical model for the optimization of process variables including acid concentration, pretreatment temperature and time. The optimum conditions determined by this model were found to be 108?C for 80 minutes with acid concentration of 5.8%. Under these conditions, the maximised results are the following: xylose 19.93 g/L, glucose 1.2 g/L, furfural 1.5 g/L, acetic acid 1.3 g/L. The validation of the model indicates a good agreement between the experimental results and the predicted values.

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