Static and dynamic sorption of lignin removed Populus euramericana

TAPPI Journal ◽  
2018 ◽  
Vol 17 (02) ◽  
pp. 71-77 ◽  
Author(s):  
Haizhen Zhou ◽  
Jingyu Li ◽  
Erni Ma
Keyword(s):  
Relative Humidity ◽  
Dynamic Condition ◽  
Moisture Sorption ◽  
Adsorption And Desorption ◽  
Dynamic Conditions ◽  
Populus Euramericana ◽  
Dynamic Sorption ◽  
Initial Stage

To investigate the effect of lignin on moisture sorption behaviors of wood under static and dynamic conditions, Populus euramericana cultivars measuring 20 mm tangentially × 20 mm radially × 4 mm along the grain was divided into three groups: untreated, extractives removed, and lignin removed. All the samples were subjected to static sorption where relative humidity (RH) was controlled at 11%, 45%, and 75%, and dynamic sorption where RH changed sinusoidally between 45% and 75% for cyclic periods of 1 h and 24 h, both conditions kept at 25C°. Moisture changes were measured during the adsorption and desorption processes. Moisture of the samples varied rapidly at the initial stage during static sorption. The rate decreased gradually until equilibrium was reached. Moisture changes for dynamic condition were generally sinusoidal but lagged behind the imposed RH.

Dynamic moisture sorption and hygroexpansion of Populus euramericana Cv. under two cyclic hygrothermal conditions

Holzforschung ◽  
2016 ◽  
Vol 70 (12) ◽  
pp. 1191-1199 ◽  
Author(s):  
Tiantian Yang ◽  
Erni Ma ◽  
Jianhui Zhang
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Environmental Conditions ◽  
Moisture Sorption ◽  
Longitudinal Direction ◽  
Measured Data ◽  
Populus Euramericana ◽  
Dimensional Changes ◽  
Unit Change ◽  
Condition B

Abstract Poplar (Populus euramericana Cv.) specimens, 20 mm in radial (r) and tangential (t) directions with thicknesses of 4 mm and 10 mm along the longitudinal direction, were subjected to cyclic environmental conditions, in the course of which the relative humidity (RH) changed sinusoidally between 75% and 45% at 20°C (condition A), or the temperature (T) was changed sinusoidally within 5–35°C at 60% RH (condition B). Moisture content (MC), as well as the t- and r-dimensional changes were measured as a response to the dynamic environmental conditions. The measured data also changed sinusoidally but they lagged behind the triggering original RH or T data. This effect was much higher under condition A than under condition B. The observed equivalent RH and T changes at different ΔMCs or Δts served for comparison of the responses to RH and T, and the former were less pronounced than the latter. MC and t-dimensional changes per unit change of RH were greater than those per unit change of T but still lower than static values. In summary, the effects of dynamic RH change are larger than those of T, especially concerning MC responses compared to dimensional changes.

scholarly journals Moisture Sorption and Thermodynamic Properties of Wood under Dynamic Condition

2016 ◽  
Vol 2016 ◽  
pp. 1-8 ◽  
Author(s):  
Tiantian Yang ◽  
Erni Ma
Keyword(s):  
Thermodynamic Properties ◽  
Moisture Content ◽  
Molecular Level ◽  
Dynamic Condition ◽  
Moisture Sorption ◽  
Adsorbed Water ◽  
Specimen Thickness ◽  
Dynamic Sorption ◽  
Sorption Hysteresis ◽  
Two Temperatures

Thermodynamic approach is a useful method to study interactions between water and wood at molecular level. This work investigated the dynamic moisture sorption and thermodynamic properties for two thick poplar woods (Populus euramericanaCv.) subjected to sinusoidal relative humidity (RH) changes between 45% and 75% for cyclic period of 1, 6, and 24 h, at two temperatures of 25°C and 40°C. Moisture changes of the specimens were measured during the successive adsorption and desorption processes, giving the following results: (1) moisture content changed sinusoidally with the imposed RH and was inversely related to specimen thickness as well as temperature, but in a positive correlation with cyclic periods; (2) all ofQL,ΔG, andTΔSof the adsorbed water during dynamic sorption decreased with increasing moisture content or specimen thickness and decreasing cyclic period. However, temperature had opposite effects onΔGandTΔS. (3) Both moisture sorption hysteresis and thermodynamic sorption hysteresis could be found. The former became weak with rising temperature or thicker specimens, while the latter got clear when temperature or specimen thickness increased.

EFFECT OF MOISTURE CONTENT ON VIABILITY AND INFESTATION OF HULLESS TERRA OATS IN STORAGE

1979 ◽  
Vol 59 (4) ◽  
pp. 911-916 ◽  
Author(s):  
R. N. SINHA ◽  
N. D. G. WHITE ◽  
H. A. H. WALLACE ◽  
R. I. H. McKENZIE
Keyword(s):  
Relative Humidity ◽  
Moisture Content ◽  
Mite Infestation ◽  
Tyrophagus Putrescentiae ◽  
Adsorption And Desorption ◽  
Safe Storage ◽  
Moisture Contents ◽  
Seed Moisture ◽  
Effect Of Moisture

The effects of various seed moisture contents in hulless (cv. Terra) and hulled oats (cv. Random) on susceptibility to mite infestation and on mycofloral growth and germination loss were studied at weekly intervals. Fat acidity values were determined for Terra oats only after 4 wk of storage. Moisture content-relative humidity adsorption and desorption curves were determined for Terra at 22 °C and at relative humidities of 35–100%. Terra oats, which had a higher level of Penicillium infection at 90–100% RH than Random oats, lost viability more rapidly than Random. Fat acidity values of Terra increased rapidly from 35 mg KOH/100 g of seed to 87–118 mg KOH/100 g of seed, only when seeds were stored at 90–100% RH. Terra offered a more favorable substrate for the multiplication of the mites Tyrophagus putrescentiae, Acarus farris, and Lepidoglyphus destructor than did Random. With the exception of susceptibility to mite infestation, safe storage criteria are similar for hulled and hulless oats at usual moisture contents.

scholarly journals Dynamická sorpční kapacita malých ochranných filtrů – průmyslové škodliviny

2021 ◽  
Vol 20 (1) ◽  
pp. 23-31
Author(s):  
Vlastimil Sýkora ◽  
◽  
Čestmír Hylák
Keyword(s):  
Czech Republic ◽  
Relative Humidity ◽  
Sorption Capacity ◽  
Sulphur Dioxide ◽  
Test Substance ◽  
Civil Protection ◽  
The Czech Republic ◽  
Dynamic Sorption ◽  
Input Parameters

The aim of the study was to assess the effects of input parameters on the value of dynamic sorption capacity of small protective filters used in the civil protection of the Czech Republic. Relative humidity, the concentration of the test substance/air mixture, type of filter, year of manufacture, batch and type of sorbent, were used as the monitored parameters. The measurements were performed using a gas-air mixture bas ed on cyclohexane, ammonia, sulphur dioxide, chlorine and sulfane. MOF, MOF-2, MOF-4, MOF-5 and MOF-6-M filters were used for the measurements. It has been detected that the tested filters in many cases meet the requirements of the relevant Standard for sorption capacity, namely in cases of cyclohexane, sulfane and sulphur dioxide. It has also been established that MOF-4 filters containing medium-grained sorbent SZS-1000 attained lower values of sorption capacity than filters with CHS-5 sorbent.

Adsorption and Desorption of Cu / Zn Ions with Triethylenetetramine-Functionalized Adsorbents: Kinetics Study

2012 ◽  
Vol 209-211 ◽  
pp. 1999-2004
Author(s):  
Chang Kun Liu ◽  
Xu Xin Zhao ◽  
Hong Zhu ◽  
Xiao Fang Yue
Keyword(s):  
Adsorption Kinetics ◽  
Metal Ion ◽  
Single Species ◽  
Desorption Kinetics ◽  
Adsorption And Desorption ◽  
Diffusion Controlled ◽  
Initial Stage ◽  
And Performance ◽  
Two Stages ◽  
Zn Ions

Adsorption and desorption kinetics is critical in the efficiency and performance evaluation of the adsorbents. In this study, the adsorption and desorption kinetics of copper and/or zinc ions was investigated with the polyamine-functionalized adsorbents (P-TETA). The adsorption kinetics was studied in both single species system (when only one metal ion was present) and binary species system (when both metal ions were present). The adsorption kinetics in single species system was well fitted with two models at two stages for both Cu and Zn ions, indicating that the adsorption was diffusion-controlled at the initial stage and attachment-controlled at later stage. The adsorption kinetics in binary species system revealed the stronger coordination affinity of Cu ion with P-TETA than Zn ion. The desorption kinetics was well fitted with Elovich model for Cu ion desorption only, in both single and binary species system, with a higher desorption rate in single species system.

Dynamic moisture sorption and dimensional stability of furfurylated wood with low lignin content

Holzforschung ◽  
2019 ◽  
Vol 74 (1) ◽  
pp. 68-76
Author(s):  
Tiantian Yang ◽  
Erni Ma ◽  
Jinzhen Cao
Keyword(s):  
Relative Humidity ◽  
Dimensional Stability ◽  
Furfuryl Alcohol ◽  
Lignin Content ◽  
Moisture Sorption ◽  
Dimensional Change ◽  
Poplar Wood ◽  
Sorption Coefficient ◽  
Dimensional Changes ◽  
Sinusoidal Shape

AbstractDegradation of lignin occurs naturally in wood due to the influence of microorganisms or photic radiation. To improve the properties of wood with low lignin content, furfuryl alcohol (FA) at the concentration of 25% was used to modify poplar wood (Populus euramericana Cv.) after partial delignification. Moisture sorption and dimensional stability of the samples were investigated under dynamic conditions where the relative humidity (RH) was changed sinusoidally between 45% and 75% at 25°C. Both the moisture content (MC) and the tangential dimensional change varied with a sinusoidal shape similar to the RH. Hygroscopicity and hygroexpansion increased after delignification, while furfurylation led to an inverse impact by reducing MC, dimensional changes, amplitudes of MC and dimensional changes, moisture sorption coefficient (MSC), and humidity expansion coefficient (HEC). After delignification and further furfurylation, the MC and the dimensional changes were reduced by about 20%, and the maximum drop in amplitudes of MC and dimensional changes was about 30%, while the MSC and the HEC decreased by over 15%. In addition, the furfurylated wood with low lignin content exhibited lower sorption hysteresis and swelling hysteresis.

scholarly journals Moisture sorption isotherms of castor beans. Part 1: Mathematical modeling and hysteresis

2016 ◽  
Vol 20 (8) ◽  
pp. 751-756 ◽  
Author(s):  
André L. D. Goneli ◽  
Paulo C. Corrêa ◽  
Gabriel H. H. de Oliveira ◽  
Osvaldo Resende ◽  
Munir Mauad
Keyword(s):  
Moisture Content ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Environmental Condition ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherms ◽  
Different Temperatures ◽  
The Difference ◽  
The Stability ◽  
And Storage

ABSTRACT Sorption isotherms are of great importance in post-harvest procedures, especially for predicting drying and storage, which help to establish the final moisture content of the product under certain environmental condition. Hysteresis is a phenomenon that occurs due to the difference between adsorption and desorption curves, which aids the evaluation of chemical and microbiological deteriorations, indicating the stability of stored products. Moisture sorption isotherms of castor beans were determined and hysteresis was analyzed. Static gravimetric technique at different temperatures (25, 35, 45 and 55 ± 1 °C) was used. Saturated salt solutions in the range of 37-87% ± 2% were utilized to create the required controlled relative humidity environment. Equilibrium moisture content data were correlated by different mathematical models and the Modified Halsey model presented good adjustment for the data, according to statistical procedures. Hysteresis between adsorption and desorption isotherms is present over the range of 0.2-0.9 of water activity, regardless of the temperature. This phenomenon decreases with temperature increase.

Moisture Sorption Isotherms and Isosteric Heats of Sorption of High-Pressure Treated Paulownia Wood under Different Storage Conditions

2019 ◽  
Vol 62 (1) ◽  
pp. 105-114
Author(s):  
Xiuping Jiang ◽  
Xiuping Jiang ◽  
Huanhuan Li ◽  
Hosahalli S. Ramaswamy ◽  
Songming Zhu ◽  
...  
Keyword(s):  
High Pressure ◽  
Gravimetric Method ◽  
Sorption Isotherms ◽  
Moisture Sorption ◽  
Storage Conditions ◽  
Sorption Behavior ◽  
Adsorption And Desorption ◽  
Moisture Sorption Isotherm ◽  
Moisture Sorption Isotherms ◽  
Paulownia Wood

Abstract. Understanding of moisture sorption isotherms (MSI) is critical for predicting the stability of wood during handling, transport, and storage. The aim of this study was to evaluate the adsorption and desorption isotherm characteristics of high-pressure (HP) treated paulownia wood and to identify the best-fitting model to describe its sorption behavior. The equilibrium moisture contents (EMCs) of HP-treated paulownia wood were obtained using a static gravimetric method under different storage conditions: three temperatures (20°C, 30°C, and 40°C) and five water activity (aw) levels (0.32 to 0.95). Results showed that HP parameters did not significantly affect the MSI trend of treated groups. Eight modified models (modified Chung-Pfost, modified Henderson, modified Oswin, modified Halsey, Chen-Clayton, Guggenheim-Anderson-de Boer (GAB), simply modified GAB, and Peleg) were fitted to the experimental data. The Chen-Clayton model (temperature-dependent) produced randomized residuals and the best prediction performance for both adsorption and desorption among all models. Net isosteric heat of adsorption and desorption decreased from 7.55 to 4.84 kJ mol-1 and from 18.1 to 12.2 kJ mol-1, respectively, with an increase in EMC from 7.5% to 10%. The isosteric temperature (Tß) was 352 K for adsorption and 335 K for desorption, between which all the adsorption and desorption reactions proceeded at the same rate. All thermodynamic functions were adequately characterized by a power law model. Keywords: Equilibrium moisture content, High-pressure treatment, Modeling, Moisture sorption isotherm, Paulownia wood, Temperature, Thermodynamic analysis.

Resorcinol-Formaldehyde Resins for Cesium Removal from Solutions Produced after Processing Spent Ion-Exchangers

2020 ◽  
Vol 842 ◽  
pp. 107-114
Author(s):  
Eduard Tokar' ◽  
Marina Palamarchuk ◽  
Mikhail Tutov ◽  
Anna Matskevich ◽  
Andrei Egorin
Keyword(s):  
Chemical Stability ◽  
Contact Time ◽  
Sorption Properties ◽  
Molar Ratio ◽  
Ion Exchangers ◽  
Resorcinol Formaldehyde ◽  
Dynamic Conditions ◽  
Cesium Removal ◽  
Dynamic Sorption ◽  
Short Contact Time

A series of resorcinol-formaldehyde resins (RFR) has been prepared and studied in terms of Cs-137 uptake efficiency from solutions (0.75М NaOH-2.25M NaNO3) intended for processing spent ion-exchangers. Sample synthesized at molar ratio of resorcinol to formaldehyde of 1.8:2.2 and solidified at 210 °C (sample RFR-3-1-210) has shown the best sorption-selective performance and chemical stability. Implementing RFR in dynamic sorption scheme enables to reduce its decay due to short contact time. In dynamic conditions, after feeding 1000 bed volumes of the solution, RFR 3-1-210 maintains its sorption properties after 6 sorption-desorption cycles.

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