Bentonite–Acrylamide Hydrogels Prepared by the Nonmixing Method: Characterization and Properties
7
Citation
27
Reference
10
Related Paper
Citation Trend
Abstract:
A significant amount of research has been conducted on bentonite–acrylamide hydrogels. These gels are usually prepared by uniformly mixing bentonite with reactive monomers. Herein, a new preparation method of bentonite–acrylamide hydrogels has been proposed to cater to one novel application of bentonite–acrylamide hydrogels. In this method, bentonite–acrylamide hydrogel was obtained by pressing bentonite into a thin mud cake and extruding a mixed liquor of acrylamide, a cross-linking agent, an initiator, and water into the thin mud cake and then subjecting the system to water-bath curing. The effects of extrusion pressure, extrusion time, and acrylamide concentration on the tensile strength and elemental composition of bentonite–acrylamide hydrogel were investigated. The results show that the tensile strength of the bentonite–acrylamide hydrogel first increased and then tended to be stable with the further increase in extrusion pressure and extrusion time. As the concentration of acrylamide increased, the tensile strength of the bentonite–acrylamide hydrogel increased first and then decreased slightly. With the increase in extrusion pressure, extrusion time, and acrylamide concentration, the contents of C and N elements in the thin mud cake gradually increased and then tended to be stable, which reflects the state of the monomer entering the thin mud cake. In addition, the elemental composition of the bentonite–acrylamide hydrogel was analyzed via the scanning electron microscopy–energy dispersive X-ray spectrometry method, and it was found that the composition of the hydrogel was relatively uniform in the direction of mixed liquor extrusion.Keywords:
Bentonite
Difference of sodium dodecyl benzene sulfonate(SDBS) was degradated by 0.5% TiO2-bentonite and 0.5% reused TiO2-bentonite separately under 6 w ultraviolet lamp within 6h was compared.Original concentration of SDBS was 20 mg/L and the cause of difference was discussed.The results showed that:(1) Reduction of SDBS in solution which was treated by the TiO2-bentonite and by the reused TiO2-bentonite was 86.3% and 46.2% separately.Although the efficiency of reduction of SDBS treated by reused TiO2-bentonite was lower,the result showed that TiO2-bentonite can be reused.(2) Compared with the lattice structure of TiO2-bentonite,the lattice structure of reused TiO2-bentonite was not changed obviously.(3)Compare with the efficiency of SDBS reduced by TiO2-bentonite,its inefficient t reduced by reused TiO2-bentonite was that some of Ti in reused TiO2-bentonite was washed out when TiO2-bentonite was first used.(4) Contents of organic matter of reused TiO2-bentonite were higher remarkably than those of TiO2-bentonite.The longer time ultraviolet lamp shine,the lower contents of organic matter of reused TiO2-bentonite.SDBS was absorbed by TiO2-bentonite first,and then was degradated.(5) Concentration of SO42-in solution was higher when TiO2-bentonite was reused than that when TiO2-bentonite was first used.SO42-came mainly from degradation of SDBS.
Bentonite
Ultraviolet
Cite
Citations (0)
The relatively weak mechanical properties of hydrogels remain a major drawback for their application as load-bearing tissue scaffolds. Previously, we developed cell-laden double-network (DN) hydrogels that were composed of photocrosslinkable gellan gum (GG) and gelatin. Further research into the materials as tissue scaffolds determined that the strength of the DN hydrogels decreased when they were prepared at cell-compatible conditions, and the encapsulated cells in the DN hydrogels did not function as well as they did in gelatin hydrogels. In this work, we developed microgel-reinforced (MR) hydrogels from the same two polymers, which have better mechanical strength and biological properties in comparison to the DN hydrogels. The MR hydrogels were prepared by incorporating stiff GG microgels into soft and ductile gelatin hydrogels. The MR hydrogels prepared at cell-compatible conditions exhibited higher strength than the DN hydrogels and the gelatin hydrogels, the highest strength being 2.8 times that of the gelatin hydrogels. MC3T3-E1 preosteoblasts encapsulated in MR hydrogels exhibited as high metabolic activity as in gelatin hydrogels, which is significantly higher than that in the DN hydrogels. The measurement of alkaline phosphatase (ALP) activity and the amount of mineralization showed that osteogenic behavior of MC3T3-E1 cells was as much facilitated in the MR hydrogels as in the gelatin hydrogels, while it was not as much facilitated in the DN hydrogels. These results suggest that the MR hydrogels could be a better alternative to the DN hydrogels and have great potential as load-bearing tissue scaffolds.
Gelatin
Gellan gum
Cite
Citations (52)
Health problems caused by aluminium salts have been recently reported. Various reports have mentioned the direct and indirect toxic effects of metals in the form of tumours, cancers, and allergies. In order to replace aluminium salts as adsorbents and coagulants, the capability of bentonite and combination of bentonite used as coagulants in wastewater treatment via adsorption, ion exchange, and coagulation-flocculation processes were investigated. The optimum conditions (pH and coagulants dosage) were identified for bentonite, the combinations of bentonite-zeolite, bentonite-alum, and bentonite-limestone. The investigation conducted found that bentonite can be a good coagulant which can absorb Chemical Oxygen Demand (COD) for 90.5% of removal. Based on the optimum dosage of the combinations of bentonite, bentonite-zeolite mixture gave high efficiency removal of iron (98%) and turbidity (95%) from others. Meanwhile, the bentonite-limestone mixture produced less sludge volume index and showed lowest zeta potential values. The zeta potential of treated bentonite and bentonite mixed were -26.7 mV for bentonite-alum, -20.7 mV for raw bentonite, -19.9 mV for bentonite-zeolite, and -17.6 mV for bentonite-limestone which demonstrated the coagulation and adsorption process occurred. On the other hand, the effects of contact time indicated that the adsorption capacity of combination bentonite was higher than raw bentonite.
Bentonite
Alum
Zeta potential
Cite
Citations (30)
The high quality Na-bentonite were prepared from low grade Ca-bentonite.The expanded times was 3.6 times of raw bentonite,the galotinous times was 2.2 times of raw bentonite.Main technical conditions effected on the quality of product were studied systematically.
Bentonite
Cite
Citations (0)
Under the reaction condition that/=2.4,polymerized hydroxyl Al ion prepared by Al3+ and alkali liquor and thereby inorgano pillared bentonite,organo pillared bentonite and inorgano-organo pillared bentonite prepared by acetyl trim ethylamine bromide(CTMAB).XRD result indicates that the interlayer spacing of bentonite is increased obviously and reaches to 1.9 nm or more.IR also indicated that Na-bentonite after polarization,pillaring species enter into the interlayer of bentonites.After studying the removing effect of inorgano-pillared bentonite,organo-pillared bentonite and inorgano-organo-pillared bentonite on the above four kinds of organism,the experimental result showed that the adsorption behavior of 3 kinds of pillared bentonites on organism is much better than raw bentonite.When dropping 0.2g,86.77%、97.26%、90.81% of nitrophenol was adsorbed.
Bentonite
Hectorite
Ethylamine
Cite
Citations (0)
On the basis of introducing the new progress in the studying on purified bentonite,activated bentonite,modified bentonite by cation-exchang reaction,preparation of organo-bentonite and inorgano-organo-bentonite.We summarized the problem of modifying bentonite and forsee the prospect of the modified-bentonite.
Bentonite
Cite
Citations (0)
The relatively weak mechanical properties of hydrogels remain a major drawback for their application as load-bearing tissue scaffolds. Previously, we developed cell-laden double-network (DN) hydrogels that were composed of photocrosslinkable gellan gum (GG) and gelatin. Further research into the materials as tissue scaffolds determined that the strength of the DN hydrogels decreased when they were prepared at cell-compatible conditions, and the encapsulated cells in the DN hydrogels did not function as well as they did in gelatin hydrogels. In this work, we developed microgel-reinforced (MR) hydrogels from the same two polymers, which have better mechanical strength and biological properties in comparison to the DN hydrogels. The MR hydrogels were prepared by incorporating stiff GG microgels into soft and ductile gelatin hydrogels. The MR hydrogels prepared at cell-compatible conditions exhibited higher strength than the DN hydrogels and the gelatin hydrogels, the highest strength being 2.8 times that of the gelatin hydrogels. MC3T3-E1 preosteoblasts encapsulated in MR hydrogels exhibited as high metabolic activity as in gelatin hydrogels, which is significantly higher than that in the DN hydrogels. The measurement of alkaline phosphatase (ALP) activity and the amount of mineralization showed that osteogenic behavior of MC3T3-E1 cells was as much facilitated in the MR hydrogels as in the gelatin hydrogels, while it was not as much facilitated in the DN hydrogels. These results suggest that the MR hydrogels could be a better alternative to the DN hydrogels and have great potential as load-bearing tissue scaffolds.
Gelatin
Gellan gum
Cite
Citations (0)
Bentonite has been widely used in industry, agriculture and other fields as a kind of nonmetallic materials. In recent years, the continuous study and the application on bentonite have been further extended. This paper analyses the thermal effects of bentonite and organo-bentonite by thermal analysis method. The influence of organic compound on bentonite is studied via the reaction of bentonite with organic compound solution of different concentration.
Bentonite
Cite
Citations (0)
Fe3+ modified bentonite was firstly prepared by ion change method and Fe2+ modified bentonite was then synthesized by reduction of Fe3+-bentonite. The modified bentonites were characterized with XRD and SEM. The adsorption ability of Tetracycline (TC) of Fe3+-bentonite and Fe2+-bentonite was compared with raw bentonite. The catalytic activity of two Fe-bentonites used as heterogeneous Fenton catalyst are also examined. The resulted shows that both of Fe3+-bentonite and Fe2+-bentonite exhibited superior removal performance of TC. The removal capacities of Fe3+-bentonite and Fe2+-bentonite in the 400 mg/L TC solution reached 98.15% and 96.55%, respectively. The Fe3+-bentonite and Fe2+-bentonite remains 75% removal abilities after 3 rounds under Fenton condition. The mechanisms of adsorption and Fenton degradation of Fe modified bentonite were also discussed.
Bentonite
Degradation
Cite
Citations (1)
Radiation initiated grafting is a very promising area in the field of polymers. To make a backbone hydrohilic different vinyl monomers have been grafted onto the polymeric backbone. Here acrylamide, methyl acrylamide and N, N-dimethyl acrylamide were grafted on the cellulose acetate backbone using y-radiation from 60 Co source. Different parameters like total dose, concentration, temperature and time were varied during grafting of N, N-dimethyl acrylamide. Extent of grafting followed the order AM> Me AM > N, N-dimethyl A M and for N, N-dimethyl acrylamide highest grafting was obtained at 40% monomer concentration, at 60°C with 1.37 M rad dose. Probable reasons for difference in grafting percentage for different monomers are discussed.
Vinyl acetate
Cite
Citations (13)