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In-depth understanding of transport behavior of sulfided nano zerovalent iron/reduced graphene oxide@guar gum slurry: Stability and mobility

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Journal of Environmental Sciences 2024年第10期144卷 1-14页

作者： Yuheng Ma Wenhui You Zijiang Yang Zhongyu Ren Qi Jing Faculty of Architecture Civil and Transportation EngineeringBeijing University of TechnologyBeijing 100124China

Nanoscale zero-valent iron(NZVI),which has the advantages of small particle size,large specific surface area,and high reactivity,is often injected into contaminated aquifers in the form of ***,the prone to passivation and agglomeration as well as poor stability andmobility of NZVI limit the further application of this technology in ***,sulfided NZVI loaded on reduced graphene oxide(S-NZVI/rGO)and guar gum(GG)with shearthinning properties as stabilizers were used to synthesize S-NZVI/rGO@GG ***,TEM,and FT-IR confirmed that the dispersion and anti-passivation of NZVI were optimized in the coupled *** stability and mobility of the slurry were improved by increasing the GG concentration,enhancing the pH,and decreasing the ionic strength and the presence of Ca^(2+)ions,respectively.A modified advection-dispersion equation(ADE)was used to simulate the transport experiments considering the strain and physicochemical deposition/***,colloidal filtration theory(CFT)demonstrated that Brownian motion plays a dominant role in themigration of S-NZVI/rGO@GG slurry,and the maximummigration distance can be increased by appropriately increasing the injection ***-Derjaguin-Landau-Verwey-Overbeek(XDLVO)theory showed that the excellent stability and migration of S-NZVI/rGO@GG slurry mainly came from the GG spatial *** study has important implications for the field injection of S-NZVI/rGO@GG *** to the injection parameters,the injection range of S-NZVI/rGO@GG slurry is effectively controlled,which lays the foundation for the promotion of application in actual fields.

关键词： S-NZVI rGO guar gum Transport Stability

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Novel succinoylated carboxymethyl guar gum nanocarriers of glimepiride for controlling type-2 diabetes

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Medicine in Novel Technology and Devices 2024年第2期22卷 133-139页

作者： Harsh Yadav Biswajit Maji Sabyasachi Maiti Department of Pharmacy Indira Gandhi National Tribal UniversityAmarkantakMadhya PradeshIndia Department of Chemistry Indira Gandhi National Tribal UniversityAmarkantakMadhya PradeshIndia

In this study,guar gum(GG)was chemically modified to its carboxymethyl derivative,which was then esterified with octenyl succinic anhydride(OSA)using a nucleophilic catalyst 4-dimethylaminopyridine(DMAP)to render the derivative amphiphilic *** carboxymethyl guar gum(CMGG)and succinoylated CMGG was characterized using Fourier transform infrared spectroscopy(FTIR)*** amphiphilic CMGG synthesized using DMAP/OSA ratio of 0.5:1(CMGGOSA-I),was found to be *** amphiphilic guar gum self-assembled in water to form nanocarriers with mean diameter of 430 nm and zeta potential of19.0 *** electron microscope(TEM)image showed spherical nature of the developed CMGGOSA-I nano*** presence of amphiphilic CMGG,the aqueous solubility of glimepiride was enhanced by about *** nanocarriers released glimepiride in simulated gastrointestinal fluids for a period of more than 24 h,following Higuchi's ***-Peppas modeling of the drug release data revealed that a combination of swelling and diffusion mechanism was operative in the event of drug *** streptozotocin-induced diabetic rat model,the nanocarriers outperformed pure drug suspensions in terms of anti-diabetic activity,which lasted up to 24 ***;the newly synthesized amphiphilic CMGG nanocarriers demonstrated controlled drug release properties and showed promise for controlling type-2 diabetes.

关键词： guar gum Glimepiride Octenyl succinic anhydride Anti-diabetic efficacy

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INTERMOLECULAR AND INTRAMOLECULAR INTERACTIONS OF POLYMER guar gum IN SOLUTIONS

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Chinese Journal of Polymer Science 2005年第5期23卷 557-559页

作者： Yun-fei Yan Hai-yang Yang Wen-yong Liu Ping-ping Zhu Ping-sheng He Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 China Structure Research Laboratory University of Science and Technology of China Hefei 230026 China

The tetrahedral borate ion can crosslink with polymer guar gum in aqueous solutions. If the concentration of guar gum is less than 0.045 g/dL, the intramolecular interaction between guar gum and borate ion increases due to the formation of crosslinks. As a result, the polymer chains of guar gum in solution shrink in size and the reduced viscosity of polymer solution decreases accordingly. On the other hand, if the concentration of guar gum is greater than 0.045 g/dL, the intermolecular interaction becomes apparent due to the same reason. The polymer chains, therefore, associate together and the reduced viscosity of polymer solution increases considerably. According to this technique, the critical concentration c^＊, presented by de-Gennes, is determined successfully.

关键词： guar gum Crosslink reaction Critical concentration c^*.

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EFFECT OF ANIONIC SURFACTANT UPON THE VISCOSITY OF POLYMER guar gum SOLUTIONS

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Chinese Journal of Polymer Science 2006年第4期24卷 437-440页

作者：杨海洋 Department of Polymer Science and Engineering University of Science and Technology of China Hefei 230026 China

The reduced viscosity of polymer guar gum solutions containing a certain concentration of sodium dodecyl benzene sulfonate （SDBS） was measured. It has been found that the Huggins coefficient kH of polymer solutions is very sensitive to the concentration of the surfactant, CSDBS, in solutions. If CSDBS is lower than CMC, the critical micelle concentration of SDBS, kH increases rapidly with CSDBS. On the other hand, if CSDBS is larger than CMC, kH decreases rapidly with CSDBS. Comparatively, the intrinsic viscosity of polymer solution does not show a notable change with CSDBS. The experimental results indicate that the interchain association of polymer guar gum in solution is greatly associated with SDBS interacted with polymer chains through hydrogen bonds. However, the effect of SDBS upon the intrachain association of polymer guar gum solution is negligible, presumably due to the fact that guar gum is a slightly stiffened random-coil chain polymer.

关键词： guar gum Surfactant Huggins coefficient Critical micelle concentration.

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Strength properties of xanthan gum and guar gum treated kaolin at different water contents

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Journal of Rock Mechanics and Geotechnical Engineering 2021年第5期13卷 1160-1172页

作者： Irem Bozyigit Akbar Javadi Selim Altun Department of Civil Engineering Ege UniversityBornova-IzmirTurkey College of Engineering Mathematics and Physical SciencesUniversity of ExeterExeterUK

Nowadays,using biopolymer as a ground improvement method has become very ***,since biopolymers are organic and degradable,their long-term effect is not fully *** this study,the effects of biopolymers on the mechanical behavior of kaolin clay were investigated through a comprehensive program of *** types of biopolymer,*** gum and guar gum were chosen to investigate the effect of biopolymer *** this purpose,specimens were prepared using standard Proctor energy at four different water contents(25%,30%35%and 40%)with 0.5%,1%,1.5%and 2%biopolymer *** specimens were cured for 1 d,7 d,28 d and 90 ***,some of the specimens were kept in the curing room for 3 years to observe the long-term effect of the *** the end of the curing periods,the specimens were subjected to unconfined compression test,and scanning electron microscopy(SEM)analysis was performed to observe the mechanism of strength *** results revealed that the unconfined compressive strength(UCS)of the specimens treated with biopolymers increased in all biopolymer inclusion levels and water contents up to a 90-d curing *** specimens containing xanthan gum,the maximum strength increase was observed at 25%water content and 2%xanthan gum with 90-d *** strength increased 5.23 times induced by xanthan gum addition when compared to the pure ***,the increase in strength reached 8.53 times in specimens treated with guar ***,increasing water content caused more ductile behavior,thus increasing the axial deformation.

关键词： Biopolymer Clay Unconfined compressive strength(UCS) Xanthan gum guar gum Strength properties

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High molecular weight guar gum assisted settling of fine solids in diluted bitumen:Effect of solvents

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Petroleum Science 2021年第6期18卷 1877-1886页

作者： Camila Santander Jing Liu Xiao-Li Tan Qi Liu Hong-Bo Zeng Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 1H9Canada

As water-based extraction technologies for producing bitumen from oil sands have received increasing environmental concerns,developing non-aqueous extraction(NAE)technique is of both fundamental and practical ***,the relatively high concentration of fine solids trapped in the extracted bitumen presents an obstacle for pipeline transport as well as upgrading and refining *** research attempts to provide a solution to fine solids removal without using synthetic additives or affecting bitumen recovery from NAE ***,naturally hydrophilic additives(i.e.,water and high molecular weight guar gum(HGG)produced from Cyamopsiste tragonolobuosr ***.)were introduced to promote the settling of fine solids suspended in bitumen-solvent solution,and the effects of solvents(i.e.,toluene,cyclohexane and their mixtures)were systematically *** size distribution analyzed by the focused beam reflectance measurements confirmed that the addition of water and HGG could promote the agglomeration and settling of fine solids in all solvents ***,the size range and quantity of the agglomerates vary significantly with the solvent's aromatic *** mixtures demonstrate a superior performance on removing fine solids from bitumen over single ***,in a 3:2 toluene/cyclohexane mixture,the solid content was lowered from 0.66 wt%to 0.09 wt%.

关键词： Non-aquoues extraction Fine solids guar gum Agglomeration Settling

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Synthesis of Hydroxypropyl guar gum by Phase Transfer Catalysis

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Chinese Chemical Letters 2005年第4期16卷 545-546页

作者： RongChunXIONG MingZhuCHANC JianMingCHEN NanZHOU GangWEI BeijingUniversityofChemicalTechnology Beijing100029

HGG (Hydroxypropyl guar gum) was synthesized by phase transfer catalysis for the first time. The effects of alkalinity, phase transfer catalyst, etherification, pH value, temperature, reaction time and stirring speed were investigated. An optimal synthetic reaction technology was established, namely, dose of guar gum is 100 g, propylene oxide 40-50 g, HTAC (hexadecyl trimethyl ammonium chloride ) 1.3-1.7 g, pH value 10-10.5, temperature 45-50℃, and reaction time 3-4 hours. The result shows that the improved HGG has high viscosity. Its dissolution speed, content of insoluble residue, colloid light transparency and stability are apparently superior to guar flour.

关键词： guar gum hydroxypropyl guar gum chemical modification phase transfer catalysis.

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Effect of wettability of ceramic proppant surface in guar gum solution on the oil flow efficiency in fractures

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Petroleum 2019年第4期5卷 388-396页

作者： Kanjicai Dong Ming Wang Chi Zhang University of Louisiana at Lafayette-Petroleum Engineering Department USA

guar gum and its derivatives have been the most commonly used polymers to increase the viscosity of fracture *** proppants are vital products for enhancing oil and gas well productivity in low-permeability *** the last several decades,abundant studies have been found in the investigation of proppant size,shape,compositions on the fracture ***,few types of research can be found to study the proppant wettability effect on the oil and gas flow *** our research,eight experiments were conducted using traditional guar gum fracturing *** of this work indicated that ceramic proppant promotes oil flow efficiency from sandstone core samples to proppant packs and thus should promote oil well *** mechanism behind this phenomenon is believed to be the formation of oil flow channels across the fracture face due to the imbibition of oil in the core onto the oil-wet surface of the proppant,promoting oil flow from the core to the *** guar gum was added the results inverted,this phenomenon for water-wet proppant is believed to be increased by the viscosity of fracture fluids which increased the viscosity of water,promoting oil flow from the core to the ***,the stimulation effect of oil-wet proppant on oil flow efficiency can be reduced by the presence of guar gum *** the proppant matrix filled with guar gum fracturing fluid,oil can be blocked inside the proppant matrix as a discontinuous phase while the aqueous phase can be easily mixed with the guar gum fluid and then be transferred out.

关键词： Fracturing Proppant Surface wettability Oil flow efficiency guar gum

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Synthesis of Novel Nanocomposites of Silica and guar gum:Efficient Zinc Ion Binder

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复旦学报（自然科学版） 2007年第5期46卷 721-722页

作者： Vandana Singh Sadanand Pandey Somit kumar Singh Rashmi Sanghi Department of Chemistry University of Allahabad 302 Southern Laboratories Facility for Ecological and Analytical TestingIndian Institute of Technology

1 Results Adsorption using commercial activated carbon (CAC)[1] can remove heavy metals from wastewater[2-4].However,CAC remains an expensive material for heavy metal *** exchange techniques are also used but it generates volumetric sludge and increases the cost[5].Using naturally occurring seed polysaccharides can solve these problems but their solubility in water limits its application as an *** gum is a commercially available,industrially important[6-7] polysaccharide material havi...

关键词： nanocomposite silica guar gum zinc ion binder

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Microwave Assisted Synthesis of guar gum Grafted Acrylic Acid/Nanoclay Superabsorbent Composites and Its Use in Crystal Violet Dye Absorption

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Green and Sustainable Chemistry 2016年第1期6卷 11-25页

作者： S. B. Shruthi Chandan Bhat S. P. Bhaskar G. Preethi R. R. N. Sailaja Chemical Engineering Department Dayananda Sagar College of Engineering Kumaraswamy Layout Bengaluru India Resource Efficient Process Technology Application The Energy and Resources Institute Bengaluru India

Natural gums can be tailored and used for the removal of toxic dyes like crystal violet via grafting techniques. However, grafting via microwave irradiation showed both higher yield and fast reaction kinetics as compared to conventional grafting. Silane modified nanoclay has been used to prepare acrylic acid grafted guar gum nanocomposites via microwave irradiation technique. The grafting was confirmed via infrared spectroscopy while XRD diffractograms suggested exfoliation of modified nanoclay in guar gum grafted acrylic acid. The reaction kinetic parameters have been optimized. The effect of nanoclay on swelling characteristics has been examined. The sensitivity of pH on swelling capabilities has also been assessed. The efficiency of the superabsorbent nanocomposite on the absorption of crystal violet dye has been studied. The superabsorbent nanocomposite loaded with 1.75% modified nanocaly was found to be optimal concentration for the removal of crystal violet dye.

关键词： Microwave guar gum Superabsorbent Nanocomposites Dye Absorption

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