Preparation and Swelling Properties of P(AMPS-co-AM)/ Attapulgite Clay Superabsorbent Composite by Microwave Irradiation

2012 ◽  
Vol 512-515 ◽  
pp. 2394-2398 ◽  
Author(s):  
Ji Hong Xu ◽  
De Xin Tan ◽  
Ling Yan Yan ◽  
Zhong Li
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Water Retention ◽  
Salt Water ◽  
Absorption Capacity ◽  
Water Absorbency ◽  
Swelling Properties ◽  
Superabsorbent Composite ◽  
Speed Up ◽  
Attapulgite Clay

A novel poly(2-acrylamido-2-methylpropa-nesulfonicacid-co-acrylamide) / attapulgite (P(AMPS-co-AM)/APT) high-salt superabsorbent composite was synthesized through graft polymerization in aqueous solution by microwave irradiation. The structure of the composite was characterized by infrared spectra (FTIR).The influence of the content of monomer, microwave power and the ratio of attapulgite clay on water absorbency was investigated. The swelling behaviors and the water retention of Superabsorbent resin with different APT content were also examined. The results show that the graft copolymerization took place between APT and organic monomers. Adding an appropriate amount of APT in resin can effectively improve the absorption capacity and salt-water performance. Microwave power is 390W, APT amount is 7.5% (mass fraction),The water absorbency of resin in distilled water and 0.9wt% NaCl were 1460g / g and 114 g / g. The resin has a faster absorption rate and strong water retention, the appropriate increase the amount of APT can significantly speed up the rate of the resin absorbent and improve its water retention.

scholarly journals Preparation of a low-cost and eco-friendly superabsorbent composite based on wheat bran and laterite for potential application in Chinese herbal medicine growth

2018 ◽  
Vol 5 (5) ◽  
pp. 180007 ◽  
Author(s):  
Jiande Gao ◽  
Jin Liu ◽  
Hui Peng ◽  
Yaya Wang ◽  
Sha Cheng ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Acrylic Acid ◽  
Chinese Herbal Medicine ◽  
Wheat Bran ◽  
Water Retention ◽  
Low Cost ◽  
Water Retention Capacity ◽  
Water Absorbency ◽  
Chinese Herbal ◽  
Superabsorbent Composite

A low-cost and eco-friendly superabsorbent composite is prepared through the free-radical graft co-polymerization of wheat bran (WB), acrylic acid (AA) and laterite (LA) in an aqueous solution. Elemental map, scanning electron microscopy and Fourier transform infrared spectra revealed that the LA evenly distributed in the superabsorbent composite and wheat bran-g-poly(acrylic acid)/laterite (WB-g-PAA/LA) formed successfully. Thermogravimetric analysis confirmed that the WB-g-PAA/LA had high thermal stability. Furthermore, the properties of the WB-g-PAA/LA, such as swelling in saline solutions and degradation, are also assessed. The final WB-g-PAA/LA (5 wt%) superabsorbent composite attained an optimum water absorbency of 1425 g g −1 in distilled water and 72 g g −1 in 0.9 wt% NaCl solution. The water absorbency of WB-g-PAA/LA (10 wt%) is even greater than that of the WB-g-PAA. Moreover, the water-retention capacity of WB-g-PAA/LA (5 wt%) is high, and the water-retention process followed a zero-order reaction. The reaction rate constant is 8.2428 × 10 5 exp(− E a /RT ) and the apparent activation energy ( E a ) is 35.11 kJ mol −1 . Furthermore, WB-g-PAA/LA (5 wt%) may regulate the release of urea, indicating that the superabsorbent composite could provide a promising application as a urea fertilizer carrier. Additionally, it increased the germination and growth rates of Glycyrrhiza uralensis Fisch, suggesting it could influence the growth of Chinese herbal medicine.

Preparation of Straw Superabsorbent Composite Material by Microwave Method

2013 ◽  
Vol 873 ◽  
pp. 337-343
Author(s):  
Lian Wei Yang ◽  
Rui Jie Wang
Keyword(s):  
Composite Material ◽  
Acrylic Acid ◽  
Water Retention ◽  
Salt Water ◽  
High Water ◽  
Sodium Acrylate ◽  
Microwave Method ◽  
Water Absorbency ◽  
Distilled Water ◽  
Preparation Conditions

By microwave method, a superabsorbent function composite material was prepared by grafting sodium acrylate onto straw flour using potassium persalfate (K2S2O8) and N, N'-methylene bis acrylamide as an initiator and crosslinker, respectively. The effect of various preparation conditions on its water absorbency was investigated. When the straw flour content was 6%, the acrylic acid content was 20.0g, the amount of initiator was 0.4%, the neutralization degree of monomer was 80%, the reaction temperature was 70°C and the amount of crosslinker was 0.05%, the materials absorbency was 1360 times in distilled water and 152 times in 0.9% salt-water at ambient temperature. It had also high water retention. The analyses of SEM indicate that sodium acrylate is grafted on the polysaccharides of straw flour.

scholarly journals Effects of microwave irradiation on the moisture content of various wood chip fractions obtained from different tree species

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Monika Aniszewska ◽  
Krzysztof Słowiński ◽  
Ewa Tulska ◽  
Witold Zychowicz
Keyword(s):  
Moisture Content ◽  
Microwave Irradiation ◽  
Microwave Power ◽  
Irradiation Time ◽  
Initial Moisture Content ◽  
Radiant Energy ◽  
Wood Chip ◽  
Wood Chips ◽  
Chip Size ◽  
Drying Rates

AbstractThe paper proposes the use of microwave irradiation to lower the initial moisture content of wood chips. The study involved willow and fir chips fractionated by means of a sieve separator and unfractionated ash chips. The wood chips were exposed to a constant microwave power of 800 W for 30 s, 60 s, 120 s and 180 s. The chips were weighed before and after irradiation to measure loss of moisture. It was found that the decline in moisture content increased with wood chip size for a given irradiation time and microwave power. The initial moisture content of wood chips was not found to significantly affect loss of moisture as the drying rates of wood chips with higher and lower moisture content exposed to microwaves were not statistically different. The results showed that irradiation intensity increased with the time of exposure to microwaves and unit radiant energy per unit of evaporated moisture decreased with increasing wood chip size in the 3.15–31.50 mm range.

Preparation and Water Absorbency of Superabsorbent Kaolin/PAA-AM Composite

2013 ◽  
Vol 634-638 ◽  
pp. 1968-1976 ◽  
Author(s):  
Shi Han Shen ◽  
Yu Yu Zhang ◽  
Tian Bin Li ◽  
Qing Le Zeng
Keyword(s):  
Composite Material ◽  
Complex Structure ◽  
Water Absorbency ◽  
Solution Polymerization ◽  
Mass Ratio ◽  
Reaction Conditions ◽  
Superabsorbent Composite ◽  
Optimum Reaction ◽  
The Fourier Transform ◽  
Composite Variables

In this paper, a novel superabsorbent composite material based on acrylic acid (AA), acrylic amide (AM) and inorganic kaolin was synthesized via solution polymerization in aqueous medium with N,N’-methylene bisacrylamide (MBA) as crosslinker and potassium persulfate (KPS) as initiator. The effects of water absorbency of the composite variables, such as neutralization, kaolin concentration and MBA concentration, on the water absorbency were systematically optimized. Evidence of compositing was obtained by a comparison of the Fourier transform infrared spectra of the initial reactants with that of the superabsorbent composites, and its complex structure was confirmed with scanning electron microscope. The water absorbing mechanism was also discussed. The results indicated that the superabsorbent composite material was successfully synthesized and the optimum reaction conditions were as follows: the neutralization degree was 80%, the dosage of kaolin, crosslinker and initiator were 4%, 0.11%, and 0.9% respectively and the mass ratio of AA and AM was 3∶2. The optimum absorbency of the superabsorbent composite material in distilled water could reach 815.6g/g.

Microwave Assisted Synthesis of Schiff Bases: A Green Approach

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Mousumi Chakraborty ◽  
Sanjay Baweja ◽  
Sunita Bhagat ◽  
TejpalSingh Chundawat
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Mass Spectra ◽  
Molar Ratio ◽  
Microwave Assisted Synthesis ◽  
Schiff’S Bases ◽  
Microwave Assisted ◽  
Green Approach ◽  
Schiff's Bases ◽  
Effects Of Temperature

Abstract In the present study Schiff’s bases are synthesized by the conventional as well as by microwave irradiation. Excellent yield within short reaction time is obtained using microwave irradiation along with other advantages like mild reaction condition, non-hazardous and safer environmental conditions. The effects of temperature, reactant molar ratio, and microwave power variation on yield are observed. Mathematical model has been developed using matlab software to obtain the yield as a function of microwave power. Kinetic study of the reaction has also been attempted. Schiff’s bases structures are confirmed by IR, 1HNMR, Mass Spectra and elemental analysis.

Meso-mechanics simulation analysis of microwave-assisted mineral liberation

2015 ◽  
Author(s):  
Qin Like ◽  
Dai Jun ◽  
Yuan Liqun
Keyword(s):  
Energy Consumption ◽  
Microwave Irradiation ◽  
Power Density ◽  
Microwave Power ◽  
Mineral Content ◽  
Crystal Size ◽  
Irradiation Time ◽  
Mineral Crystal ◽  
Microwave Assisted ◽  
Time And Energy

Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value.

Coupling Swelling and Water Retention Processes in Compacted Bentonite

2011 ◽  
Vol 6 (1) ◽  
Author(s):  
Antti Lempinen
Keyword(s):  
Water Retention ◽  
Spent Nuclear Fuel ◽  
Effective Strain ◽  
Swelling Pressure ◽  
Model Parameters ◽  
Confined Water ◽  
Swelling Properties ◽  
Compacted Bentonite ◽  
Buffer Material ◽  
Swelling Factor

Compacted bentonite is the main candidate for buffer material in several plans for spent nuclear fuel repositories. One of its important properties is high swelling capacity, which is caused by interaction between water molecules and exchangeable cations. This interaction makes bentonite behave differently from capillary materials. In this article, a model for thermo-hydro-mechanical state of partially water saturated bentonite is presented. It couples the water retention and swelling properties with introduction of the swelling factor in effective strain. The Helmholz energy density determines the state with a relatively small set of independent parameters: swelling pressure, swelling factor, maximum confined water content and the reference state. The model parameters are determined from experimental data for FEBEX bentonite, and as a simple consistency check, confined suction curves are calculated and compared to test results. Consistency of the model with observations on nano- and microscale of bentonite is also discussed.

scholarly journals Uncatalysed Polycondensation of Lactic Acid to Polylactic Acid Under Microwave Irradiation: Effect of Microwave Power

2020 ◽  
Vol 1551 ◽  
pp. 012001
Author(s):  
S. M. Shahrul Nizan Shikh Zahari ◽  
Muhammad Humaidi Mansor ◽  
Hazeeq Hazwan Azman ◽  
Dzulfadli Rosli
Keyword(s):  
Lactic Acid ◽  
Microwave Irradiation ◽  
Polylactic Acid ◽  
Microwave Power ◽  
Irradiation Effect

Preparation, Characterization and Swelling Behaviours of a Novel Multifunctional Superabsorbent Composite Based on Ca-Montmorillonite and Sodium Humate

e-Polymers ◽  
2007 ◽  
Vol 7 (1) ◽  
Author(s):  
Yian Zheng ◽  
Aiqin Wang
Keyword(s):  
Graft Copolymerization ◽  
Water Absorbency ◽  
Optimal Conditions ◽  
Nacl Solution ◽  
Inorganic Component ◽  
X Ray Diffraction ◽  
Salt Solutions ◽  
X Ray ◽  
Sodium Humate ◽  
Superabsorbent Composite

AbstractIn this work, a novel water-managing superabsorbent composite was prepared by graft copolymerization reaction using acrylic acid (AA) and acrylamide (AM) as the monomers, calcium montmorillonite (Ca-MMT) as an inorganic component and sodium humate (SH) as fertilizer, and well characterized by means of Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA). The effects of the reaction temperature, neutralization degree of AA, amount of crosslinker, initiator, Ca-MMT and SH on water absorbencies were systematically investigated. The water absorbencies of the superabsorbent composite synthesized under optimal conditions with a Ca-MMT content of 20 wt% and an SH content of 30 wt% are 615 g g-1 and 45 g g-1 in distilled water and in 0.9 wt% NaCl solution, respectively. The swelling behaviours of the superabsorbent composite in various cationic salt solutions (NaCl, CaCl2 and FeCl3) were also investigated and it was found that at the same saline concentration (> 0.1 mmol L-1), the effect of three cationic salt solutions on the swelling capability has the following order: NaCl < CaCl2 < FeCl3. Here, it is worthy to point out that the water absorbency and swelling behaviours of the developed composite were improved by introducing simultaneously Ca-MMT and SH into PAA-AM network in comparison with that of incorporated single with Ca-MMT or SH.

Treatment of Acidic Wastewater by Microwave Irradiation Fenton’s Reagent

2013 ◽  
Vol 864-867 ◽  
pp. 1680-1683
Author(s):  
Xiao Tong Guan ◽  
Da Wei Yu
Keyword(s):  
Microwave Irradiation ◽  
Microwave Power ◽  
Irradiation Time ◽  
Removal Rate ◽  
Fenton’S Reagent ◽  
Optimal Conditions ◽  
Fenton's Reagent ◽  
Secondary Pollution ◽  
Cod Removal Rate ◽  
Acidic Wastewater

Acidic wastewater was treated by microwave irradiation Fenton’s reagent, the effect factors: initial concentration of wastewater, dosage of H2O2, microwave irradiation time, microwave power and pH on Acidic wastewater were investigated. The optimal conditions of operation are determined as follows: microwave power is 480W, microwave irradiation time is 5min, H2O2 is 2.0mL and FeSO4 is 0.07g, pH=1. Under these conditions, the COD removal rate is 90.15% for 50mL Acidic wastewater（be diluted ten times）.The result of wastewater treated by microwave irradiation Fenton’s reagent is obvious, and without secondary pollution to environment.

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