Synthesis and Rheological Survey of Xanthan Gum Based Terpolymeric Hydrogels

Author(s):  
Muhammad Irfan ◽  
Mansoor Khan ◽  
Tanzil ur Rehman ◽  
Ijaz Ali ◽  
Luqman Ali Shah ◽  
...  

AbstractGraft copolymerization technique was used to synthesize novel biopolymer based terpolymeric hydrogels of xanthan gum (Gx), acrylic acid and N-Isopropyl acrylamide (NIPAM) by using chemical crosslinker N,N′-methylene bisacrylamide (MBA), ammonium persulphate (APS) as a redox initiator and sodium dodecyl sulphate (SDS) for particle size stabilization. The synthesized hydrogels were characterized through FT-IR and SEM techniques, which confirmed the hydrogels formation. Detailed rheology was investigated through applying various rheological models like Bingham model, modified Bingham model and Ostwald power law model to the hydrogels which revealed that the hydrogels were appeared to have shear thinning, non-Newtonian behavior and more elastic. Modified Bingham model provided best fit understanding to our prepared materials. The maximum activation energy (Ea) 13.87 kJ/mol was obtained for composition having more Gx compared to others, showing a strong relationship with viscosity. The hydrogels has potential to find applications in food industry, cosmetics, degradation of dyes and removal of heavy metals from waste water.

2019 ◽  
Vol 8 (1) ◽  
pp. 256-271 ◽  
Author(s):  
Imran Ali ◽  
Changsheng Peng ◽  
Dichu Lin ◽  
Iffat Naz

Abstract The leaves extract of Fraxinus chinensis Roxb was used for the synthesis of the innovative phytogenic magnetic nanoparticles (PMNPs) without adding toxic surfactants. The formation, morphology, elemental composition, size, thermal stability, structure and magnetic properties of these PMNPs were examined by UV-visible spectrophotometry, FT-IR, XRD, SEM, EDX, TEM, VSM, XPS, BET and TGA. The reactivity of the obtained PMNPs against decolourising toxic dyes, namely, malachite green (MG), crystal violet (CV) and methylene blue (MB), were investigated by UV-vis spectrophotometry. Further, the factors affecting the removal of dyes, including solution pH, adsorbent dosages, initial concentration of dyes, reaction temperature and contact time, were also investigated. The results revealed the decolourisation of 99.12% of MG and 98.23% of CV within 60 min, and 97.52% of MB within 200 min by the PMNPs using dyes concentration of 25 mg/l at pH 6.5 and 298.15 K. The kinetics outcome indicated that the degradation of dyes matched well to the pseudo first-order reaction kinetics model. Furthermore, the probable degradation mechanism of dyes by the PMNPs, including the adsorption of cationic dye molecules onto the negatively charged surface of adsorbent and the oxidation of the Fe° in the solution, were discussed. Thus, the PMNPs can be produced by the bulk and have great potential to be employed for biomedical/environmental remediation.


2013 ◽  
Vol 643 ◽  
pp. 17-20
Author(s):  
Ke Feng Xiao ◽  
Zhi Hui Hao ◽  
Lei Lei Wang ◽  
Xiu Guang Feng

By orthogonal experiments, optimal formulation of 1% abamectin microcapsule suspensions was determined as follow: the proportion of abamectin microcapsule is 1%, NNO 5.0%, sodium dodecyl sulfate 3.0%, xanthan gum 0.3%, ethylene glycol 3%, and the remainder is water. The indicators of the formulation are all excellent: good dispersibility, suspension rate greater than 90%, cold storage and hot storage syneresis rates under 5%. The properties of biochemical materials were used in optimization. The optimal formulation provides an experimental basis for industrial production of abamectin microcapsule suspensions.


2015 ◽  
Vol 103 (6) ◽  
Author(s):  
Mamdoh R. Mahmoud ◽  
Mohamed A. Soliman ◽  
Karam F. Allan

AbstractAdsorption behavior of samarium(III) radionuclides from aqueous solutions onto a novel polyacrylonitrile coated with sodium dodecyl sulfate (PAN@SDS), prepared by gamma radiation-induced polymerization, was studied in this work. The developed polymeric adsorbent was characterized by FT-IR, X-ray diffraction and N


2019 ◽  
Vol 3 (1) ◽  
pp. 31 ◽  
Author(s):  
Seyed Hosseini-Kaldozakh ◽  
Ehsan Khamehchi ◽  
Bahram Dabir ◽  
Ali Alizadeh ◽  
Zohreh Mansoori

Today, the drilling operators use the Colloidal Gas Aphron (CGA) fluids as a part of drilling fluids in their operations to reduce formation damages in low-pressure, mature or depleted reservoirs. In this paper, a Taguchi design of experiment (DOE) has been designed to analyse the effect of salinity, polymer and surfactant types and concentration on the stability of CGA fluids. Poly Anionic Cellulose (PacR) and Xanthan Gum (XG) polymers are employed as viscosifier; Hexadecyl Trimethyl Ammonium Bromide (HTAB) and Sodium Dodecyl Benzene Sulphonate (SDBS) have been also utilized as aphronizer. Moreover, bubble size distributions, rheological and filtration properties of aphronized fluids are investigated. According to the results, the polymer type has the highest effect, whereas the surfactant type has the lowest effect on the stability of CGA drilling fluid. It was also observed that increasing salinity in CGA fluid reduces the stability. Finally, it should be noted that the micro-bubbles generated with HTAB surfactant in an electrolyte system, are more stable than SDBS surfactant.


Polymers ◽  
2018 ◽  
Vol 10 (12) ◽  
pp. 1318 ◽  
Author(s):  
Bo Li ◽  
Jinbo Yao ◽  
Jiarong Niu ◽  
Jianyong Liu ◽  
Le Wang ◽  
...  

Much research has focused on improvement of the structural and mechanical properties of regenerated keratin materials by physical or chemical methods in recent years. In this research, regenerated keratin materials were modified with graphene oxide (GO). The properties of modified keratin films and the mechanism of interaction between GO and keratin macromolecules were studied. The SEM and XRD test results showed that the orientation of keratin macromolecules could be effectively improved by GO, which favored improvement of the keratin material’s crystallinity and made the films more uniform and compact. The thermal stability and mechanical properties of GO-modified keratin films were also improved significantly. At the same time, the reaction mechanism between keratin and GO materials was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), FT-IR, and Raman spectroscopy. It was shown that there was no chemical reaction between GO and keratin molecules, and the interaction between them was mainly via hydrogen bonding and van der Waals forces.


Materials ◽  
2021 ◽  
Vol 14 (17) ◽  
pp. 4987
Author(s):  
Elżbieta Adamska ◽  
Karolina Niska ◽  
Anna Wcisło ◽  
Beata Grobelna

Core-shell structures are the most common type of composite material nanostructures due to their multifunctional properties. Silver nanoparticles show broad antimicrobial activity, but the safety of their utilization still remains an issue to tackle. In many applications, the silver core is coated with inorganic shell to reduce the metal toxicity. This article presents the synthesis of various materials based on silver and silica nanoparticles, including SiO2@Ag, Ag@SiO2, and sandwich nanostructures—Ag@SiO2@Ag—and the morphology of these nanomaterials based on transmission electron microscopy (TEM), UV-Vis spectroscopy, and FT-IR spectroscopy. Moreover, we conducted the angle measurements due to the strong relationship between the level of surface wettability and cell adhesion efficiency. The main aim of the study was to determine the cytotoxicity of the obtained materials against two types of human skin cells—keratinocytes (HaCaT) and fibroblasts (HDF). We found that among all the obtained structures, SiO2@Ag and Ag@SiO2 showed the lowest cell toxicity and very high half-maximal inhibitory concentration. Moreover, the measurements of the contact angle showed that Ag@SiO2 nanostructures were different from other materials due to their superhydrophilic nature. The novel approach presented here shows the promise of implementing core-shell type nanomaterials in skin-applied cosmetic or medical products.


2008 ◽  
Vol 2 (1) ◽  
pp. 141-153
Author(s):  
Jerzy Szerafin

Dispersial nature of cement grout makes many difficulties in practical applications of the injection process. It is also difficult to describe by theoretical equations. The rheological models treat cement paste as continuous material. In this paper the new flow equation was derived, which contains the factor of the friction between cement grains introduced to the Bingham model. The possibilities of the calculation of this new factor was presented. The analysis of the calculation’s results of the classical and new equations shows significant differences. The new equation allows to better predict the effects of the real injection applications.


2021 ◽  
Author(s):  
Chengchen Liu ◽  
Jiaxin Lin ◽  
Haojia Chen ◽  
Wanjun Wang ◽  
Yan Yang

Abstract The potential application of biochar in water treatment is attracting interest due to its sustainability and low production cost. In the present study, H3PO4-modified biochar (H-PBC), ethylenediaminetetraacetic acid-modified biochar (E-PBC), and NaOH-modified biochar (O-PBC) were prepared for Ni(II) and Pb(II) adsorption in an aqueous solution. Scanning electron microscopy (SEM), X-ray diffraction analysis, Brunauer–Emmett–Teller analysis, and Fourier transform infrared (FT-IR) spectroscopy were employed to characterize the as-obtained samples, and their capacities for Ni(II) and Pb(II) adsorption were determined. SEM showed that H-PBC retained the hierarchical porous structure of pristine biochar, and projections were observed on its surface. FT-IR showed that H-PBC possessed abundant oxygen-containing and phosphorus-containing functional groups on the surface. H-PBC, E-PBC, and O-PBC all exhibited excellent performance at Ni(II) and Pb(II) adsorption with qmax values of 64.94 mg/g, 47.17 mg/g, and 60.24 mg/g, and 243.90 mg/g, 156.25 mg/g, and 192.31 mg/g, respectively, which were significantly higher than the adsorption capacity (19.80 mg/g and 38.31 mg/g) of pristine biochar. Pseudo-second order models suggested that the adsorption process was controlled by chemical adsorption. Regeneration analysis showed that H-PBC had superior reusability characteristics. H-PBC had a greater adsorption capacity than other adsorbents due to its large specific surface area, and abundant oxygen-containing and phosphorus-containing functional groups. The results obtained in this study suggest that H-PBC is a promising adsorbent for the removal of heavy metals from aqueous solutions.


2021 ◽  
Vol 19 (2) ◽  
pp. 31-37
Author(s):  
Layth S. Jasim ◽  
Aseel M. Aljeboree

In this Study, hydrogel P(CH/AA-co-AM) was prepared, identification and utilized as an efficient absorbent to eliminate Cr (III) and Cd (II) ions from the aqueous solution. The adsorption of these ions follows Freundlich isotherms. Due to greater activity surface of the hydrogel in adsorption of the contaminants, they can be utilized for elimination of the mentioned ions from water. Therefore, we characterized structural, surface and thermal properties of the prepared materials with technique: TGA, FE-SEM and FT-IR. Moreover, we implemented the kinetics of sorption with regard to the amounts of the metal sorbet at distinct time intervals and thus examined the modeling of the isotherm and kinetic curves. Finally, we computed the reaction order as well as rate constant.


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Asif A. Qaiser ◽  
Rabia Nazar ◽  
Mehroz Anjum ◽  
Anem Saeed ◽  
Muhmmad Zeeshan ◽  
...  

Abstract This study elucidates the effects of composition and temperature on the rheological behavior of chocolate milk formulation. The fat [0.5, 1 and 1.5 g] and xanthan gum contents [0.05, 0.1 and 0.15 g] varied and shear stress-strain rate data were recorded at varying temperature [21.4, 65 and 80 °C]. All compositions showed predominantly a pseudoplastic behavior [i.e., pseudoplasticity index, n < 1] with a strong influence on composition and temperature. Three semi-empirical rheological models, i.e. Power-law, Herschel–Bulkely, and Casson models were fitted on the data using an in-house developed computer program for the best statistical fit. The pseudoplasticity index [n] varied with the composition that initially decreased with temperature and subsequently increased. The other model parameters such as consistency index [k], Casson and Herschel–Bulkely yield stress, and Casson viscosity [at a specified rate i.e., 34.7 s−1] were computed through model fitting and correlated to the microstructural changes inside the fluid keeping in view the composition and temperature. This study helps in correlating chocolate milk processing and quality control based on complex microstructure to the rheological parameters measured at simulated temperatures and shear rates.


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