IMPREGNATED RESINS CONTAINING DI-(2-ETHYLHEXYL) THIOPHOSPHORIC ACID FOR THE EXTRACTION OF PALLADIUM(II). I. PREPARATION AND STUDY OF THE RETENTION AND DISTRIBUTION OF THE EXTRACTANT ON THE RESIN.

ABSTRACT

Solvent impregnated resins containing di-(2-ethylhexyl) thiophosphoric acid(DEHTPA) were prepared by direct adsorption of the extractant onto Amberlite XAD2 using a dry impregnation method. The impregnated resins were characterized by means of potentiometnc titrations and specific surface area measurements, and a new method to determine DEHTPA content in the resin based on surface area measurements, is proposed. The distribution of DEHTPA between the aqueous phase and the resin phase was studied, and the data obtained     

乙酸预浸对玉米秸秆蒸汽爆破预处理的影响

对经乙酸预浸汽爆预处理的玉米秸秆进行了组分含量和抑制物分析,并研究了玉米秸秆预处理后的酶水解性和同步糖化发酵。与未经乙酸预浸相比,乙酸预浸玉米秸秆能在相对低温下进行汽爆预处理,在提高半纤维素水解程度的同时,并不会明显增加糠醛等发酵抑制物。酶水解实验表明,玉米秸秆经乙酸预浸,再以 200 ℃ 进行汽爆后的酶水解效果较好,每克原料可获得 284 mg 葡萄糖,提高了 10.2 %,为理论值的 76.8 %;乙酸预浸玉米秸秆经过 96 h 同步糖化发酵,获得了 22.5 g/L 的乙醇浓度,为理论值的 72 %;相比未经乙酸预浸的玉米秸秆,提高了11.9个百分点。     

Chemical Pulping of Steam‐Exploded Mixed Hardwood Chips

Abstract

We determined the pulping yields for steam‐exploded and untreated mixed hardwood chips for kraft pulping processes with and without anthraquinone and/or polysulphide. The pulp yield from steam‐exploded chips was 1–3% lower than from untreated chips under similar conditions. The benefit of kraft pulping with anthraquinone and/or polysulphide was found to be more pronounced for the exploded chips than for the untreated chips.     

Separate versus Simultaneous Saccharification and Fermentation of Two‐Step Steam Pretreated Softwood for Ethanol Production

Abstract

In two previous studies, optimal conditions were identified for two‐step steam pretreatment of SO₂‐ and H₂SO₄‐impregnated softwood. In the present study the yield of sugar and ethanol was determined in a process development unit where pretreatment was performed in a 10‐L reactor and simultaneous saccharification and fermentation (SSF) or enzymatic hydrolysis (EH) were performed in 30‐L reactors. The study showed that a steam pretreatment reactor should be larger than 2 L to yield acceptable results. Two pretreatment combinations were studied. In the H₂SO₄ case, the first pretreatment step was at 180°C for 10 min with 0.5% H₂SO₄ and the second step at 210°C for 2 min with 1% H₂SO₄. In the SO₂ case, first step was at 190°C for 2 min followed by a second step at 210°C for 5 min. The concentration of SO₂ was 3% in both steps. EH and SSF were performed on the whole slurry after the second pretreatment step to determine the yield of sugars and ethanol. The liquid after the first pretreatment step was also analyzed and fermented. When SSF and EH were performed at the same dry matter content and enzymatic activity, the ethanol yield in SSF exceeded the yield obtained with EH in both pretreatment cases, even when 100% yield in the fermentation step was assumed. Thus SSF is a better process if yield is the main priority. Comparison of the yields with the two acid catalysts showed higher yields with SO₂ in both SSF and EH. The overall ethanol yield following SSF of SO₂‐impregnated and pretreated wood reached 81% of the theoretical, that is, 357 liters per metric ton of dry raw material.     

Sorption properties of wood impregnated with aqueous solution of boric acid and montan wax emulsion

Nonbiocidal techniques for wood protection have become more and more important in the last few years. One of the possible treatments to enhance wood durability is use of water repellents. In this research, the influence of one of the possible water repellents, the montan wax emulsion, on the moisturizing and the sorption characteristics of impregnated wood was investigated. To achieve a better protection against wood decay fungi, wood was impregnated with montan wax emulsion enriched with boric acid. The equilibrium moisture content (MC) was monitored during the adsorption and the desorption processes at five levels of relative air humidity (RH₁ = 20%, RH₂ = 33%, RH₃ = 65%, RH₄ = 88%, and RH₅ = 98%). Water repellence efficiency was monitored in the chamber with high RH (87%) and during dipping in the water. Impregnated samples were also exposed outdoors in a covered position for 5 months to determine MC changes according to changes in outdoor humidity and temperature. The results showed that the sorption properties of the impregnated wood are strongly related to retention of preservative solutions after impregnation and its composition. Montan wax reduced equilibrium MC of the impregnated wood up to 25% (relatively), whereas specimens impregnated with combination of montan wax and boric acid resulted in decreased MC in some cases and in increased MC in some cases. The Guggenheim–Andersen–deBoer model of sorption isotherms was fitted to experimental data to explain the sorption mechanisms. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

STEAM DRYLNG OF WOOD FUELS

ABSTRACT

The objective of this work is to investigate some of the important aspects in the design of a steam band dryer for wood fuels. For this purpose the drying of the material in a bench-scale fixed bed dryer has been studied.

Drying times and thermal efficiencies for experiments conducted under different conditions are compared. The investigated materials are soft-and hardwood chips and softwood bark.

The thermal efficiency, the part of the sensible heat which is used during one passage of the steam through the bed, increases with increasing mass load (mass of dry matter per unit area) and with decreasing steam mass flux. At a mass load of 30 kg/m the thermal efficiency is about 0.85 even at steam mass fluxes as high as 0.6 kg/m² s (1.2 m/s). The thermal efficiency proves to be almost independent of pressure and temperature of the steam.

Due to the very inhomogeneous materials the steam mass flow distribution was uneven. This causes a decreased thermal efficiency. When bark     

SO_4~(2-)/ZrO_2-CeO_2催化剂溶剂回流法合成聚乳酸

采用负载-浸渍法制备了一系列SO42-/ZrO2-CeO2固体超强酸,用于催化合成聚乳酸,考察了催化剂用量、聚合时间、聚合方法等因素对聚乳酸合成的影响。结果表明,当CeO2与ZrO2的摩尔比为1∶20,0.8 mol/L硫酸浸渍,650℃焙烧时,得到的固体超强酸酸强度最大,掺杂的CeO2处于高度分散,增强了固体超强酸的酸强度,合成的聚乳酸的分子量与固体超强酸的酸强度具有很好的相关性,当催化剂用量为乳酸质量的1%,反应时间为30 h时,得到了粘均分子量为11.6×103的聚乳酸。     

The Effect of Degree of Impregnation in Amberlite Resins with Organophosphorous Extractants for Y(III), La(III), Ce(III), Th(IV) and U(VI) Ions

Abstract

Background: The sorption of Y(III), La(III), Ce(III), U(VI) and Th(IV) ions with solvent impregnated resins using diphenylphosphate (DPP), and diphenylphosphinic acid (DPPA) as extractant and Amberlite XAD 16 and Amberlite XAD 2000 as a polymeric support has been studied. The impregnated resins containing various amounts of extractants (10/90, 20/80, 50/50, 60/40) have been prepared by a dry method. The effects of pH, types of extractant, extractant content, surface area of polymeric support and contact time have been investigated by batch method.

Results: The impregnation for DPP on XAD‐16 and XAD‐2000 was 111 and 46% at 60/40 extractant/resin mass ratio, respectively. The impregnation of DPPA at all ratios on both resins was found constant and lower than DPP. The sorption percentage of studied metal ions was within 90‐99% for DPP and DPPA on both resins after 20/80 extractant/resin mass ratio.

Conclusions: The sorption of DPP on Amberlite XAD 16 and XAD 2000 resins is rather more than DPPA. It could be seen that 20/80 extractant/resin mass ratio is generally adequate for single metal analysis where 60/40 could be suitable for multi‐metal analysis.     

Impact of impregnation with boron compounds on the surface hardness of varnished wood

This study was performed to determine the impact of impregnation with boron compounds on the surface hardness of varnished wood materials. For this purpose, test specimens prepared from Oriental beech (Fagus orientalis Lipsky) and oak (Quercus petreae Lipsky), which met the requirements of ASTM D 358, were impregnated according to ASTM D 1413 with boric acid and borax by a vacuum technique. After impregnation, the surfaces were coated by cellulosic, synthetic, polyurethane, waterborne, acrylic, and acid hardening varnishes in accordance with ASTM D 3023. The surface hardness of the specimens after the varnishing process was determined in accordance with ASTM D 4366. According to the wood type, impregnation material, and varnish type, the surface hardness was highest for the oak impregnated with borax and acrylic varnish and lowest for the oak impregnated with borax and synthetic varnish. Therefore, impregnation with boron compounds showed an increasing impact on the surface hardness of the varnished wood. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

ENERGY QUANTIFICATION AND MECHANO-SORPTIVE BEHAVIOR IN THE KILN DRYING OF 2.5 cm THICK RED OAK LUMBER

ABSTRACT

Energy consumption was quantified in the drying of 2.5 cm thick red oak lumber in a 1.2 m³ steam heated experimental dry kiln. The aluminum pre-fab kiln is located indoors and was wrapped with 5 cm thick extruded polystyrene (R=10) for the experimental drying. Transmission loss accounted for about 80% of the energy/kilogram of water removed from the wood. The maximum value was for the 60°C DBT due to comparatively high transmission loss combined with maximum venting loss. Batch venting reduced average energy consumption per kiln run by over 6% compared to the conventional kiln schedule.

Average board shrinkage was over 2% less for drying with a low temperature schedule compared to drying by the conventional schedule for red oak. This was due to less compression set developing in the board interior at low wood temperatures, accompanied by more tension set in the surface layers. The mechano-sorptive results were in full agreement with McMillen's conclusions from his research on red oak.     

改性桑树枝焦对模拟烟气中汞的吸附性能

采用固定床热解、蒸汽活化和改性剂(H₂O₂、ZnCl₂和NaCl)浸渍等方法制得不同的桑树枝焦。在固定床吸附实验台上,研究了蒸汽活化、改性剂、吸附温度和烟气组分等对改性桑树枝焦汞吸附性能的影响。结果表明:蒸汽活化显著提高了桑树枝热解焦的比表面积,H₂O₂改性可进一步提高桑树枝蒸汽活化焦比表面积并改善其孔隙结构参数,ZnCl₂和NaCl改性则降低了桑树枝蒸汽活化焦的比表面积、D-R微孔容积和总孔容。10%H₂O₂和30%H₂O₂浸渍改性桑树枝焦的单位汞吸附量分别是蒸汽活化焦的2.02倍和1.77倍;相同改性剂浓度下,ZnCl₂改性焦的单位汞吸附量比NaCl改性焦稍好;随着ZnCl₂浓度增大,改性桑树枝焦的汞吸附性能增强,MT600-A-ZnCl₂(5%)桑树枝焦的单位汞吸附量达到29.55 μg·g^-1,是蒸汽活化焦的3.37倍。在吸附温度为60～120℃范围内,H₂O₂改性焦的汞吸附效率及单位汞吸附量随着吸附温度的升高而下降,而ZnCl₂改性焦的单位汞吸附量则随着吸附温度提高呈现先增大后减小的趋势,最佳吸附温度为90℃。烟气中SO₂和NO组分对汞吸附性能有一定的抑制作用,随着SO₂和NO浓度的增加,汞吸附效率和单位汞吸附量均稍有下降。     

Surface characterization of wood treated with boron compounds combined with water repellents

Longer weathering exposure periods are more reliable for end‐use performance evaluations of wood surfaces. This study aimed to investigate the effect of boron impregnation on the surface composition and color of Scots pine (Pinus sylvestris L.) wood exposed to 18 months of natural weathering in the West Black Sea Region of Turkey. All measurements were performed at 6 month intervals. Samples were first impregnated with boron compounds and then for a second time using five different water‐repellent materials. Polyethylene glycol and aluminum sulfate were introduced with the boric acid as single impregnations. With increased weathering time, the samples darkened, while sodium silicate kept the color change to a minimum. Nano boron‐impregnated samples exhibited more effective results than those impregnated with boric acid. The FTIR analysis results demonstrated that the impregnation process had caused significant changes in the chemical structure of the samples. The changes in the chemical structure of the wood resulting from the impregnation process were partially maintained during the weathering.     

Calibration of an Aerosol Composition Mass Spectrometer with Sulfuric Acid Water Aerosol

The first quantitative chemical analysis of polar stratospheric cloud particles has recently been performed using a balloon-borne aerosol composition mass spectrometer (ACMS). A similar spectrometer is presently used in a large cryo-chamber experiment to study low temperature aerosols. All experiments require prior to their employment an accurate calibration to convert mass spectrometer signals into molecular species contained in the aerosols. For the calibration, pure H 2 SO 4 /H 2 O droplets are generated having known composition and diameters between 0.4 w m and 1 w m. The size distribution and the number concentration can be controlled. A flow reactor with a rotating inner glass cylinder placed in a H 2 SO 4 /H 2 O bath solution of known concentration is used to condition the droplets. The residence time of the particles in the flow reactor is long enough that the droplets adopt the composition of the bath solution before entering the ACMS. The result is a linear relationship between the mole ratio of the H 2 SO 4 /H 2 O droplets and the mass spectrometer count rate ratio of water to sulfuric acid. The evaluation takes the dissociation of H 2 SO 4 inside the ACMS into account. The calibration error varies between 3 and 4 wt. % H 2 SO 4 for stratospheric particles with a composition of 30-70 wt. % H 2 SO 4 . Besides the calibration of the instrument, the analysis of the aerosols is a valuable diagnostic tool to investigate impurities in the particles.     

TCF BLEACHED PULPS FROM MISCANTHUS SINENSIS BY THE IMPREGNATION RAPID STEAM PULPING (IRSP) PROCESS

ABSTRACT

The production of bleached cellulose pulps from elephant grass (Miscanthus sinensis) via a two-stage soda pulping process and a TCF bleaching sequence is evaluated in this work. The impregnation rapid steam pulping process (IRSP) involves impregnating of the lignocellulosic material with the pulping liquor, withdrawing the excess liquor and rapidly steaming the impregnated material at 180–200°C for a short time. In this paper the process variables and their effect on the kappa number, yield and viscosity of the unbleached pulps are discussed. Bleaching by an ozone-based TCF sequence was tested, and the papermaking properties of the bleached pulp were determined. A kappa number of 19 was obtained by impregnating at an alkali charge of 30 + 0.1% anthraquinone carboxylic acid (AQCA) and pulping at 180°C for only 15 min. Kappa was reduced to 16 by extending pulping time to 26 min. The alkali consumption during impregnation and pulping was 10.2 g NaOH/100 g of dry Miscanthus. Screened pulp yield, viscosity and brightness for this pulp were 54.6%, 913 mL/g and 37.3%, respectively. After bleaching, the pulp had an ISO brightness of 87.4% and a viscosity of 700 mL/g. Refining in a PFI mill provided optimal strength properties of the bleached pulp at 4500 revolutions (71°SR): breaking length 7.2 km, tensile index 72 N m/g, and burst index 4.3 kN/g. Tear index was 7.9 mN m²/g at this degree of refining.     

Improvement of white pinewood properties by impregnation with thiourea–formaldehyde resin and orthophosphoric acid

White pinewood was impregnated with thiourea–formaldehyde (TUF) resin and orthophosphoric acid (OPA) as a crosslinking agent. The best weight gains (55–138%) were obtained after impregnation with an aqueous solution of TUF resin for 1 h and impregnation with aqueous solutions of OPA at different concentrations for 1 h. Water uptake of treated wood was found to be 23% after a water‐soaking test of 168 h, and a maximum antiswell efficiency was found to be 18% for a 85% OPA solution. Compression strength of the treated wood also improved with the highest value 62 KN/m² for wood treated with a 70% OPA solution versus a value of 40 KN/m² for untreated samples. Fire retardancy of the treated wood samples was also improved based on concentration of OPA. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 390–397, 2000     

Supercritical wood impregnation

The use of supercritical fluids for delivering biocides into wood and wood composites is an attractive technique because of the high penetration capacity of these solvents compared to the liquids used in conventional treatment methods. During the past two decades supercritical wood impregnation has moved from lab scale to commercial scale.This review presents an overview of the main research efforts that has been carried out within the field of supercritical wood impregnation. Results and conclusions of research within four main categories, i.e. (1) effects of impregnation on physical properties of samples, (2) retention and distribution of biocide in impregnated samples, (3) biological performance of impregnated samples, and (4) mathematical modeling of supercritical impregnation are reviewed and discussed.     

Supercritical wood impregnation

The use of supercritical fluids for delivering biocides into wood and wood composites is an attractive technique because of the high penetration capacity of these solvents compared to the liquids used in conventional treatment methods. During the past two decades supercritical wood impregnation has moved from lab scale to commercial scale.This review presents an overview of the main research efforts that has been carried out within the field of supercritical wood impregnation. Results and conclusions of research within four main categories, i.e. (1) effects of impregnation on physical properties of samples, (2) retention and distribution of biocide in impregnated samples, (3) biological performance of impregnated samples, and (4) mathematical modeling of supercritical impregnation are reviewed and discussed.     

Sorption Properties of Wood Impregnated with Boron Compounds,Sodium Chloride and Glucose

Chemical protection is one of the possible treatment processes that influence the sorption characteristics of wood. In the present research we have investigated the influence of biocides (boric acid, borax) and their concentrations on the sorption characteristic of impregnated wood. For comparison, two other chemicals were included in the research as well (NaCl and glucose). The equilibrium moisture content during the adsorption and desorption process at five levels of relative humidity (?₁ = 20%, ?₂ = 33%, ?₃ = 65%, ?₄ = 88%, and ?₅ = 98%) was monitored. The results showed that impregnation does not influence the wood moisture content of specimens conditioned at low relative air humidity. In the upper hygroscopic region, moisture content is significantly influenced by the concentration and properties of impregnation chemicals. The Guggenheim-Andersen-deBoer (GAB) and Dent models of sorption isotherms was fitted to experimental data to explain the sorption mechanisms in detail.     

Thin-Layer Chromatography of Metal Ions in Formic Acid Medium on Impregnated and Unimpregnated Silica Gel G: Semiquantitative Determination of Fe3+, Cd2+, Th4+, Al3+, Zn2+, UO2+ 2, VO2+, Ce4+, and Ni2+

Abstract

The adsorption behavior of metal ions in the formic acid-sodium formate system using unimpregnated as well as impregnated silica gel G as thin layers has been studied. A remarkable result of this study is the dramatic selectivity of impregnated silica gel G thin layers when compared to the corresponding unimpregnated silica gel G thin layers. This impregnation effect provides us with a new adsorbent phase which is sufficiently stable in the formic acid-sodium formate medium. Some important ternary separations have been achieved on silica gel G thin layers. Al³⁺, Ni²⁺, Fe³⁺, and Pb²⁺ have been qualitatively separated from mixtures of other ions. Cu²⁺ has been selectively separated on impregnated silica gel G thin layers. The semi-quantitative determination of nine metal ions on impregnated silica gel G layers has also been attempted.     

螺杆挤压连续汽爆装置预处理秸秆试验研究

以玉米秸秆为原料,用螺杆挤压连续汽爆装置进行9组试验,考察了浸渍条件、温度和停留时间对汽爆物组分含量的影响。试验结果表明:从半纤维素水解程度以及汽爆物pH,考察不同浸渍条件的浸渍效果排序为预浸渍>预喷淋浸渍>直接喷淋;采用螺杆挤压连续汽爆装置处理玉米秸秆,在直接喷淋3%稀H2SO4溶液、温度170℃、停留时间25 min的预处理条件下,半纤维素水解成戊糖的效果最好,戊糖得率最高为7.75%。