Swelling Pretreatment Research Articles

Theoretical Calculation of Different Side-Chain Lengths [Cnmim]FeCl4 and Factors Influencing Coal Pyrolysis Swelling Modification.

With the increasing requirements for clean and effective utilization, coal swelling pretreatment provides a good theoretical basis for coal molecular structure, application in coal pyrolysis, and liquefaction. Ionic liquids containing magnetic anionic groups were designed, synthesized, and used as solvents to study the effect on swelling pyrolysis performance. Studies have shown magnetism enhancement with the growth of alkyl chains. The growth of the MIL alkyl side chain made the modification effect of coal more obvious, and the swelling degree showed a trend of first increasing and then decreasing with the increase of temperature and time, and at the temperature of 35 °C, the swelling degree is the largest when the modification time is 8 h. Pyrolysis experiments show that magnetic ionic liquid (MIL) pretreatment can significantly reduce the temperature at the maximum weight loss of coal and increase the tar content of pyrolysis, indicating that MIL plays a catalytic cracking role in coal pyrolysis.

Adjusting effects of pyrolytic volatiles interaction in char to upgrade oil by swelling waste nylon-tire

Waste nylon-tire (WNT) is a typical solid municipal waste, pyrolysis efficiently disposes WNT to produce oil containing high-value chemicals. Upgrading the quality of oil is the key to improve WNT pyrolysis economy. Herein, swelling was applied to pretreat WNT, and swelled waste nylon-tire (SWNT) was pyrolyzed at different temperatures (400 °C–600 °C). Lower than 500 °C, swelling pretreatment realized the number of compounds in oil by GC–MS decreased 59.57% at 400 °C (60.78% at 450 °C, 67.97% at 500 °C) compared to Waste nylon-tire pyrolytic oil (TPO). Over 500 °C, this phenomenon weakened, decreased 47.67% at 550 °C (11.48% at 600 °C). At 400 °C and 450 °C, long chain methyl esters yield was over 30 A.% instead of short chain alkanes in TPO. D-limonene yield was over 20 A.% in oil of swelled waste nylon-tire (STPO). From 500 °C to 600 °C, swelling pretreatment affected the relative content of BTX and PAHs. At 500 °C and 550 °C, the relative content of BTX in STPO was more than twice of TPO, and BTX reached 28.75 A.% at 600 °C. PAHs in STPO appeared at 500 °C higher than TPO (450 °C), and PAHs was 0.73 A.% at 500 °C. Swelling pretreatment could produce more larger pores in particle during pyrolysis, which sharply inhibited the interaction of volatiles inside tire, so the number of compounds in oil sharply decreased at lower temperatures. Over 550 °C, temperature became the dominant role for generating oil, and components tended to be similar for STPO and TPO. CS2 with high-volatility released quickly from WNT during pyrolysis, it could be recycled to reduce final cost and environment impacts.

Exfoliation of coarse printed circuit boards using dimethylacetamide: Production of copper concentrates

Conventional hydrometallurgy-based e-waste value recovery technique employs milled printed circuit boards (PCBs) to facilitate the reaction between the metal fraction and leaching reagents. The current work investigates value recovery using coarse PCBs (1 cm × 1 cm). Thus, organic swelling pre-treatment using dimethylacetamide is employed to produce swollen and delaminated PCBs. The adopted experimental conditions were 160 °C, solid: liquid ratio of 1:10, 150 rpm and organic swelling time (15-75 min). The field emission scanning electron microscope (FESEM) images explicitly illustrated the noticeable cracks propagation over time at different sites within the multi-layered structure of PCBs. This resulted in various delaminated PCB components (i.e. halved PCBs, compound unit, copper-glass fibre cloth laminate, copper foil and glass fibre cloth), though the delamination extent varies with time. Copper (Cu) content analysis performed on the delaminated PCB components indicated that a copper concentrate with high Cu contents could be obtained (inner Cu foil: 83.39 %; outer Cu: 88.57 %) by performing organic swelling for coarse PCBs. The swollen particles can be subjected to a less energy-intensive mechanical method to yield embedded copper foils, and it is feasible due to the pre-weakened PCBs after undergoing organic swelling. Since the removal of the electronic components is a prerequisite in organic swelling, hindrances that occurred during delamination were also identified in this work. The presence of the through-hole pins in PCBs in one such condition potentially slows down the organic swelling. The results of this work could be employed to develop alternative PCBs-based value recovery flowsheets to extract the encapsulated inner copper avoiding comminution, which is energy intensive.

Influence of coal structure change caused by different pretreatment methods on Shengli lignite pyrolysis

Coal pyrolysis is one of the methods of clean and efficient utilization of coal. Coal has a complex structure, which has an important influence on its pyrolysis characteristics. In order to further explore the structure–activity relationship between the structure and pyrolysis characteristics of coal, the structure of coal can be artificially changed to investigate the influence of structural changes on its pyrolysis characteristics. In this study, hydrothermal pretreatment (HTP) and solvent swelling pretreatment (SSP) were used to artificially change the structure of Shengli (SL) lignite. The influence of each pretreatment on the physicochemical structure was analysed by Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The evolution of functional groups and the pyrolysis characteristics of the SL/pretreated coal were investigated by using an in-situ FT-IR device and a fluidised bed reactor, respectively. The results showed: HTP could remove some oxygen-containing functional groups and aliphatic side chains, hydrolyze ether bonds and generate phenolic hydroxyl groups, thus destroying the cross-linking structure, promote the release of aromatic CC, the yield of pyrolysis tar increased from 9.4% to 10.6%, and the content of light tar increases from 43.1% to 49.1%. SSP mainly weakening the cross-linking structure by destroying hydrogen bonds and dissolving part of oxygen-containing functional groups, which reduces the pyrolysis activation energy of oxygen-containing functional groups and aliphatic groups, promotes the generation of tar. Accordingly, the yield of tar increases from 9.4% to 11.1%, and the content of light tar increases from 43.1 % to 49.8%. In particular, this research work reveals the structure–activity relationship between the structural changes of coal and the pyrolysis characteristics, which provides a theoretical basis for the directional pyrolysis of lignite.

Research on the relationship between the structure and pyrolysis characteristics of pretreated Shendong coal

Studying the relationship between the structure and pyrolysis of coal is useful for understanding the coal pyrolysis mechanism. In this study, three typical pretreatment methods (viz. hydrothermal pretreatment, tetrahydrofuran swelling pretreatment, and methane thermal pretreatment) were selected to artificially change the structure and composition of Shendong coal. Subsequently, the physicochemical structure and pyrolysis characteristics of the pretreated coals were systematically investigated. The results indicate that the three pretreatment methods had different influences on the pore modification and evolution of the functional groups in coal, thereby destroying the cross-linking structure in different ways. Correspondingly, these changes eventually altered the distribution and composition of the pyrolysis products. Based on these findings, the different mechanisms underlying the pyrolysis behavior, involving alteration of the structure and composition, were analyzed, and the structure–activity relationship between the coal structure and the pyrolysis characteristics was explored.

Synthesis of Polyaniline-Cellulose Conductive Composites with Modified Initial Treatment of Cellulose

Conductive polymers are polymers that can conduct electric current because they have conjugated double bonds. Polyaniline is one example of conductive polymers with advantages such as high conductivity, excellent environmental stability, and easy to be synthesized. Nevertheless, polyaniline still has disadvantages such as rigid physical properties that can limit its usage application. Some studies state that stiffness can be overcome by forming composites. Cellulose has been used as a matrix in making polyaniline composites because of its flexible nature. In this study, the synthesis of PANI-cellulose composites was carried out with five different treatment variations, including swelling pretreatment and without swelling pretreatment, reaction through sonication, and without sonication. This treatment difference aims to examine the effect of swelling and sonication processes on composite properties analyzed through peaks appear in Fourier Transformation Infrared spectrometry, conductivity using Electrochemical Impedance Spectroscopy, as well as differences in the diffractogram of X-Ray Diffraction. In addition to the variations in the initial treatment, variations in the mass of the aniline were also used. The aim is to determine the optimum amount of aniline used to obtain a composite with the highest conductivity value. Inserting aniline to cellulose to synthesis PANI-cellulose composites affected the absorption peaks at wave numbers that identify C-N bonds in PANI-cellulose composites. Also, there are typical peaks of C-N indicated the formation of hydrogen bonds in the composite between PANI and cellulose. Analysis with EIS shows that composite C with an aniline concentration of 2.0 g/L has the highest conductivity, which is 4.77 x 10-6 S/cm. The diffractograms show the formation of organic compounds on PANI-cellulose composites, marked by the peak intensity and widen diffraction patterns.

Effect of Swelling Pretreatment on Properties of Cellulose-Based Hydrochar

Hydrothermal carbonization (HTC) has been demonstrated as an effective method for preparing hydrochar to realize efficient utilization of biomass resources. In this study, both trifluoroacetic acid...

Fabrication of optically transparent cotton fiber composite

In this study, we fabricated optically transparent cotton fibers composite by resin impregnation without having to prepare cellulose nanofibers. Although the surface acetylation of the cotton microfibrils aided the resin impregnation process, excess acetylation resulted in the gradual breakdown of the cellulose crystal structure, with the resulting composite showing a high coefficient of thermal expansion (CTE). To prevent this, a swelling pretreatment, namely surface carboxylation by TEMPO-mediated oxidation, was performed to facilitate the surface acetylation of the microfibrils and hence the resin impregnation process. After the swelling pretreatment and the subsequent surface acetylation process, an optically transparent cotton fiber composite with a high regular light transmittance (83.23% at 600 nm) and a low CTE (19.5 ppm/K) was obtained. Finally, when this technique was used with a commercial cotton cloth, a transparent composite with a high total transmittance (88.5% at 600 nm) could be obtained.

Effects of Alkali-Cosolvent Swelling Pretreatment on Grinding Properties of BKP

Effects of Alkali-Cosolvent Swelling Pretreatment on Grinding Properties of BKP

Aqueous pretreatment for reactive ball milling of cellulose

Aqueous swelling pretreatment of cellulose was found highly effective for reactive ball milling to prepare surface-esterified cellulose nanofibers. Compared with starting from dry cellulose, water- or 2 % NaOH-pre-swollen materials were esterified and dispersed in significantly shorter milling time. Especially commercial kraft pulp was difficult to disperse even with water pretreatment, but 2 % NaOH treatment gave full surface esterification with a bulk degree of substitution of 0.69 by 12-h ball milling, presumably because of removal of non-cellulosic components.

Leaching studies for tin recovery from waste e-scrap

Printed circuit boards (PCBs) are the most essential components of all electrical and electronic equipments, which contain noteworthy quantity of metals, some of which are toxic to life and all of which are valuable resources. Therefore, recycling of PCBs is necessary for the safe disposal/utilization of these metals. Present paper is a part of developing Indo-Korean recycling technique consists of organic swelling pre-treatment technique for the liberation of thin layer of metallic sheet and the treatment of epoxy resin to remove/recover toxic soldering material. To optimize the parameters required for recovery of tin from waste PCBs, initially the bench scale studies were carried out using fresh solder (containing 52.6% Sn and 47.3% Pb) varying the acid concentration, temperature, mixing time and pulp density. The experimental data indicate that 95.79% of tin was leached out from solder material using 5.5M HCl at fixed pulp density 50g/L and temperature 90°C in mixing time 165min. Kinetic studies followed the chemical reaction controlled dense constant size cylindrical particles with activation energy of 117.68kJ/mol. However, 97.79% of tin was found to be leached out from solder materials of liberated swelled epoxy resin using 4.5M HCl at 90°C, mixing time 60min and pulp density 50g/L. From the leach liquor of solder materials of epoxy resin, the precipitate of sodium stannate as value added product was obtained at pH 1.9. The Pb from the leach residue was removed by using 0.1M nitric acid at 90°C in mixing time 45min and pulp density 10g/L. The metal free epoxy resin could be disposed-of safely/used as filling material without affecting the environment.

The Effect of Swelling Pretreatment on the Coal Liquefaction in Tetralin with Microwave Energy

Three Turkish coals, a Zonguldak coal and Tunçbilek and Beypazari lignites were used to examine the effect of solvent swelling pretreatment on the solubilization and dissolution behavior. Methanol, THF (tetrahydrofuran) and TBAH (tetrabutylammonium hydroxide) were used as swelling agents. For the investigation of dissolution behavior of coals, the microwave heating period was changed from 10 to 30 min at 5 min intervals. While solvent pretreatment enhanced the THF solubles yields for the Zonguldak coal, solvent treatment decreased the THF solubles yields for the Tunçbilek and Beypazari lignites. The data obtained in this study indicated that the formation mechanism of AS (asphaltenes), PAS (preasphaltenes) and oils depend on the coal and swelling agent type.

98/00979 Swelling pretreatment of coal for improved liquefaction at less severe conditions: Hu, H. et al. DGMK Tagungsber., 1997, 9704 (Proceedings ICCS '97, volume 3), 1465–1468

Tests were performed to study the effect of solvent swelling pretreatment of a subbituminous coal on the liquefaction at different conditions. Methanol, THF and pyridine were used as swelling agent, and the liquefaction of swollen coals and untreated coal was carried out in an autoclave apparatus. The results indicated that swelling pretreatment of coal can effectively increase the THF conversion of coal liquefaction at below 400 C. It is necessary to use some catalyst to obtain high conversion at low temperature. The FT-i.r. and SEM analyses indicated that by solvent swelling pretreatment, the coal structure becomes much more uniform while the main structure no changed. (orig.)

Swelling pretreatment of coals for improved catalytic temperature-staged liquefaction

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSwelling pretreatment of coals for improved catalytic temperature-staged liquefactionLevent Artok, Alan Davis, Gareth D. Mitchell, and Harold H. SchobertCite this: Energy Fuels 1993, 7, 1, 67–77Publication Date (Print):January 1, 1993Publication History Published online1 May 2002Published inissue 1 January 1993https://doi.org/10.1021/ef00037a012RIGHTS & PERMISSIONSArticle Views128Altmetric-Citations29LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (1 MB) Get e-Alerts Get e-Alerts

Swelling pretreatment of coals for improved catalytic liquefaction

Two coals, a Texas lignite and a Utah high volatile C bituminous, were used to examine the effects of solvent swelling pretreatment and catalyst impregnation on conversion behaviour at 275 °C, representative of the first, low-temperature stage in a temperature-staged liquefaction reaction. Iron(II) sulphate, iron pentacarbonyl, ammonium tetrathiomolybdate, and molybdenum hexacarbonyl were used as catalyst precursors. Without swelling pretreatment, impregnation of both coals increased conversion, mainly through increased yields of preasphaltenes. Methanol, tetrahydrofuran, tetrabutylammonium hydroxide, and pyridine were used as swelling agents. In the absence of catalyst, swelling the lignite before reaction improves conversion by enhancing oil and gas yields; the effectiveness of the solvents in enhancing conversion is in the same order as their swelling ratios. Swelling with methanol or pyridine has little effect on reaction of the bituminous coal, but both tetrahydrofuran and tetrabutylammonium hydroxide treatments increase conversion as a result of higher preasphaltene yields. The combined effect of catalyst addition and swelling enhances conversion, as much as two-fold, of the lignite and increases yields of all products. On the other hand, little benefit was obtained by combining catalyst addition and swelling for the bituminous coal, though it is possible to effect changes in the relative amounts of the various products. Tetrabutylammonium hydroxide not removed from the coal after pretreatment appears to decompose to the good solvent tributylamine, suggesting the possibility of using swelling agents as ‘solvent precursors’, first swelling the coal and then thermally decomposing to a strong solvent that is emplaced inside the coal. The action of iron pentacarbonyl is sensitive to the reactive gas atmosphere used; in hydrogen it decomposes to an oxide that mainly facilitates hydrogenation of the heavy products to lighter oils, whereas in hydrogen sulphide/hydrogen mixtures the iron pentacarbonyl is sulphided and mainly facilitates depolymerization of the coal to heavy products. This finding suggests the possibility of tailoring the behaviour of the catalyst by appropriate selection of catalyst precursor and reactive atmosphere.

ANIONIC TRANSITION GRAFT-POLYMERIZATION OF ACRYLAMIDE ONTO RAYON

Rayon fibers were metallated with Li, Na and K methoxides in pure methanol or a mixed solvent consisting of CH3OH and dimethyl sulfoxide (DMSO) (1:1v/v) and the metallated fibers were allowed to react with acrylamide (AAm) in various solvents by the anionic mechanism to give graft copolymer with poly-β-alanine branches as well as polyacrylamide branches.Effects of a swelling pretreatment in water or DMSO, Na metallation time and medium, and methoxide concentration upon the degree of the metallation were investigated. The degree of Na metallation increased with CH3ONa concentration for the water- or DMSO-swollen rayon and the degree of metallation was higher for the latter. The higher degree of Na metallation was obtained on the exchange reaction with CH3ONa in the mixed solvent (1:1 CH3OH•DMSO) than in pure methanol at lower concentration of CH3ONa, and the degree of Na metallation of the DMSO-swollen rayon increased with the DMSO content in the mixed solvent.Effects of the AAm concentration, degree of metallation and reaction temperature upon the total graft-on and the graft-on via transition polymerization were investigated in various solvents. The total graft-on increased with the AAm concentration in the reaction solution for the Na metallated rayon. The graft-on via transition polymerization which was determined by the analysis of prim. amide nitrogen increased with the AAm concentration and was 8_??_34% of total graft-on. The graft-on was scarcely influenced by the addition of an inhibitor of radical polymerization into the reaction solution. Apparent activation energies of the graft-polymerization were 8_??_11kcal/mol for the Na metallated rayon fibers treated in various solvents. Both curves of the total graft-on and the graft-on via transition polymerization vs. the degree of metallation with Li, Na and K had maxima at 0.22_??_0.32mol/AGU (AGU: glucose unit) and their maximum values increased with an increase in the degree of swelling of the preswollen rayon, with a decrease in the dielectric constant of the solvent in the reaction solution and with an increase in the electropositivity of the alkali metal used.