Flotation separation of quartz from magnesite using carboxymethyl cellulose as depressant

Carboxymethyl cellulose(CMC)was introduced as a depressant in reverse flotation separation of quartz from magnesite.The flotation behavior and surface properties of magnesite and quartz exposed to CMC were studied by zeta potential tests,atomic force microscopy imaging and contact angle measurements.The addition of CMC as the depressant in reverse flotation using dodecylamine(DDA)as the collector exhibited a selectively depressive performance towards magnesite and achieved an improved recovery of magnesite.The study of surface properties demonstrated that CMC and DDA exhibited different adsorption strengths on the surface of magnesite and quartz.It was found that the adsorption of CMC on magnesite surface was stronger than that of DDA,which hindered the subsequent adsorption of DDA on magnesite surface.On the contrary,the quartz surface was strongly adsorbed by DDA instead of CMC,which proved that the addition of CMC did not influence the flotation of quartz.

A Comparative Assessment of the Efficacy of Carbomer Gel and Carboxymethyl Cellulose Containing Artificial Tears in Dry Eyes

The present study aimed to compare the clinical efficacy of a 0.4% carbomer gel and 1% carboxymethyl cellulose （CMC） containing artificial tears in treatment of dry eye patients. Sixty subjects with mean age of 45.89 years who had symptoms and signs of dry eye were enrolled in this prospective, investigator-masked and stratified random sampling study. The subjects were divided into two parallel groups with 30 subjects （60 eyes） in each group. One group received carbomer gel, and the other group received 1% CMC containing artificial tears. Subjects received the drops 3 to 4 times or more per day for 3 months. At the first visit time, the precorneal residence time of these two drops was measured. The efficacy was assessed by comparing the subjective symptoms （ocular dry- ness, foreign body sensation, burning sensation and pain）, and the objective test results of tears breakup time, Schirmer＇s test and corneal fluorescein staining prior to the study and after the treat- ment. As a result, the ocular residence time of carbomer gel was significantly longer than that of 1% CMC （P〈0.001）. Most of the primary subjective symptoms and objective test results were improved after treatment in both carbomer gel group and 1% CMC group. As to the improvement of each symptom and objective test result, carbomer gel was more effective than 1% CMC group （P〈0.01）. In conclusion, carbomer gel had longer precorneal residence time and was more effective than 1% CMC in the treatment of patients with dry eyes.

Water-Resistant and Stretchable Conductive Ionic Hydrogel Fibers Reinforced by Carboxymethyl Cellulose

Conductive ionic hydrogels(CIH)have been widely studied for the development of stretchable electronic devices,such as sensors,electrodes,and actuators.Most of these CIH are made into 3D or 2D shape,while 1D CIH(hydrogel fibers)is often difficult to make because of the low mechanical robustness of common CIH.Herein,we use gel spinning method to prepare a robust CIH fiber with high strength,large stretchability,and good conductivity.The robust CIH fiber is drawn from the composite gel of sodium polyacrylate(PAAS)and sodium carboxymethyl cellulose(CMC).In the composite CIH fiber,the soft PAAS presents good conductivity and stretchability,while the rigid CMC significantly enhances the strength and toughness of the PAAS/CMC fiber.To protect the conductive PAAS/CMC fiber from damage by water,a thin layer of hydrophobic polymethyl acrylate(PMA)or polybutyl acrylate(PBA)is coated on the PAAS/CMC fiber as a water-resistant and insulating cover.The obtained PAAS/CMC-PMA and PAAS/CMC-PBA CIH fibers present high tensile strength(up to 28 MPa),high tensile toughness(up to 43 MJ/m~3),and good electrical conductivity(up to 0.35 S/m),which are useful for textile-based stretchable electronic devices.

γ⁃Fe2O3@carboxymethyl Cellulose as Potential Oral Nanomedicine for Iron Deficiency Anemia Treatment on Rats

Oral iron supplements such as ferrous iron salts are major treatment agents for iron deficiency anemia(IDA)due to the convenience of large dose administration and good patient compliance.However,the gastrointestinal adverse impact caused by Fe2+stimulus and low bioavailability severely impedes its therapeutic effects.In recent years,it has been found that nano iron⁃based nanoparticles with high surface⁃to⁃volume ratio and low iron ion leakage can alleviate the toxic effect and improve the gastrointestinal absorbance.For further clinical development,nano materials need to meet the pharmaceutical quality demand.Carboxymethyl cellulose(CMC)is a significant pharmaceutical ingredient applied in approved drug formulations,and polyglucosorbitol carboxymethylether(PSC)has been utilized in iron⁃based nanomedicine ferumoxytol synthesis,both of which can be firmly anchored on iron oxide by carboxyl chelation.In this work,iron oxide nanoparticles(NPs)modified with CMC were designed and synthesized,and the structure composition and physicochemical properties were distinctly characterized.Oral supplement effects on rat IDA were investigated and compared with other recently reported iron supplements including NPs modified with PSC.Results show that the oral nano iron supplement achieved the recovery of hemoglobin and serum iron level in only two weeks with high safety.The nano iron oxide modified with pharmaceutical excipients provides new potential approach for oral iron supplement available in clinics.

Preparation of urea-formaldehyde paraffin microcapsules modified by carboxymethyl cellulose as a potential phase change material

We prepared spherical microcapsules modified by carboxymethyl cellulose（CMC） with urea-formaldehyde（UF） resin as a shell material with a two-step process by in situ polymerization, and characterized the microcosmic features, chemical structure, and thermal performance of the microcapsules by SEM, FTIR, DSC, and TGA. We studied the effects of different experimental parameters of curing p H, the amounts of the emulsifier and emulsion speed. The CMC-UF microcapsules had good heat resistance and stability. The enthalpy of CMC-UF microcapsules reached 50.33 J g-1. Therefore, CMC-UF resin can be used as a potential wall material of phase change materials.

Absorption Capability Comparison of Two Kinds of Super Absorbent Resins from Carboxymethyl Cellulose

The two kinds of super absorbent resins from carboxymethyl cellulose were synthesized with the potassium persulphate and methylenebisacrylamide as initiator and cross linker respectively by radical polymerization in aqueous solution. Thestructures of the two resins were characterized with Fourier transform infrared spectroscopy FTIR, scanning electron miscroscopy （SEM）, and environment scanning electron miscroscopy （ESEM）, the results indicate that the fibriform of the carboxymethyl cellulose （CMC） is disappeared and the crusslink networks in eopolymer of carboxymethyl cellulose-graft-polyacrylic acid（CMC-g-PAA） are denser than that of eopolymer of carboxymethyl cellulose-graft-poly （acrylic acid-co-N-vinyl Pyrrolidone） （CMC-g- PAA-co-PVP）. The comparison between the two resins in absorption capacities is that CMC-g-PAA is better in the water-keep capability being heated, while CMC-g-PAA-co-PVP is better in the water absorbency and salt resistance.

Synthesis and characterization of carboxymethyl cellulose/organic montmorillonite nanocomposites and its adsorption behavior for Congo Red dye

A series of carboxymethyl cellulose/organic montmorillonite （CMC/OMMT） nanocomposites with different weight ratios of carboxymethyl cellulose （CMC） to organic montmorillonite （OMMT） were synthesized under different conditions. The nanocomposites were characterized by the Fourier transform infrared （FT-IR） spectrophotometer, X-ray diffraction （XRD） method, transmission electron microscope （TEM）, scanning electron microscope （SEM）, and thermal gravimetric （TG） analysis. The results showed that the introduction of CMC may have different influences on the physico-chemical properties of OMMT and intercalated-exfoliated nanostructures were formed in the nanocomposites. The effects of different reaction conditions on the adsorption capacity of samples for Congo Red （CR） dye were investigated by controlling the amount ofhexadecyl trimethyl ammonium bromide （CTAB）, the weight ratio of CMC to OMMT, the reaction time, and the reaction temperature. Results from the adsorption experiment showed that the adsorption capacity of the nanocomposites can reach 171.37 rag/g, with the amount of CTAB being 1.0 cation exchange capacity （CEC） of MMT, the weight ratio of CMC to OMMT being l：l, the reaction time being 6 h, and the reaction temperature being 60~C. The CMC/OMMT nanocomposite can be used as a potential adsorbent to remove CR dye from an aqueous solution.

Effect of carboxymethyl cellulose on dissolution kinetics of carboxymethyl cellulose-sodium carbonate two-component tablet

Sodium carbonate and carboxymethyl cellulose powders are compressed into two-component tablets with three mass ratios,97%:3%,95%:5% and 93%:7%.The dissolution tests for two-component tablets and reference pure sodium carbonate tablets are carried out at various temperatures.The dissolution process of each tablet is measured by electrical conductivity tracking method and the concentration of dissolved sodium carbonate is quanti fied with calibrated conductivity-concentration converting equation of sodium carbonate.The quanti fied dissolution data is fitted with both surface reaction model and diffusion layer model and the results clearly show that surface reaction model is suggested as the appropriate dissolution model for all measured tablets.Therefore,it is determined that carboxymethyl cellulose is a stable element to remain the dissolution mechanism of tablet unchanged.The dissolution rate constant quanti fied with surface reaction model presents that carboxymethyl cellulose-sodium carbonate two-component tablets obtain signi ficant higher dissolution rate constant than pure sodium carbonate tablet and higher proportion of carboxymethyl cellulose leads to apparent higher dissolution rate constant.The results prove for the usage of carboxymethyl cellulose in most practical applications at a relative low-level,the effect of carboxymethyl cellulose is effective and positive for two-component tablet to enhance the dissolution process and improve dissolution rate constant and this effect is speculated coming from its dynamic physical transforming process in water including dilation and conglutination.

Characterization of Carboxymethyl Cellulose Made from Bamboo Harvesting Residues

Bamboo harvesting residues are wastes by-products of bamboo industries that contain holocellulose for about 63.14%to 70.71%,which often be discarded,incinerated or buried.In this study,carboxymethyl cellulose was prepared from bamboo harvesting residues(bamboo-branch and bamboo-tip)as raw materials.The chemical composition of bamboo harvesting residues,the viscosity and degree of substitution of carboxymethyl cellulose were determined.Carboxymethyl cellulose obtained was further characterized and compared by means of FTIR,SEM,XRD and TG.Results showed that under the optimized identical conditions,the viscosity and degree of substitution of carboxymethyl cellulose from bamboo-branch and bamboo-tip were 6.0 and 78.9 mPa·s,0.75 and 0.89,respectively.Carboxymethyl cellulose obtained from bamboo-tip displayed a lower crystallinity and a better thermal stability as compared to synthetic carboxymethyl cellulose obtained from bamboo-branch and bamboo-culm.

EFFECT OF METAL IONIC SPECIES AT MINERAL SURFACES ON THE ADSORPTION OF CARBOXYMETHYL CELLULOSE

In this research it was shown that mineral surface metal-lic sites played a decisive role in carboxymethyl cellulose (CMC) adsorp-tion, and surface hydrophobicity alone did not have significant effects. Both the carboxymethyl groups and the hydroxyl groups of the CMC par-ticipated in the interaction with mineral surface, with the carboxymethyl groups interacting with metal and metal hydroxyl species, and hydroxyl groups interacting with metal hydroxide species, respectively.

Preparation and Characterization of Eco-friendly Carboxymethyl Cellulose Antimicrobial Nanocomposite Hydrogels

Carboxymethyl cellulose hydrogels were developed through crosslinking process using eco-friendly crosslinkers such as maleic,succinic,and citric acids.Carboxymethyl cellulose was prepared from the cellulosic fraction of olive industry residues.A series of hydrogels with varying crosslinker acid concentrations,reaction times,and reaction temperatures was produced to study the swelling capacities and gel fraction of the obtained hydrogels.Additional study pertains to the preparation of antimicrobial nanocomposite hydrogels through in-situ incorporation of the silver nanoparticles during the crosslinking reaction.Silver nanoparticles were prepared by reduction of AgNO3 with leaves of Ricinus communis.The particle size of prepared silver nanoparticles was detected by transmission electron microscopy(TEM).Chemical structure and morphological characterizations of the prepared hydrogels were performed using Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),and energy-dispersive X-ray spectroscopy(EDX).Finally,the antimicrobial activity of the loaded silver hydrogels against Gram negative(G-ve),Gram positive(G+ve),and Candida albicans yeast was demonstrated.

Preparation of Waterborne Nanoscale Carbon Black Dispersion with Sodium Carboxymethyl Cellulose

Waterborne nanoscale carbon black dispersion （NCBD） was widely used in inkjet printing, spun.dyeing fibers and coloration fabrics. In this paper, NCBD was prepared using sodium carboxymethyl cellulose （CMC） as dispersant. Effects of CMC viscosity, ultrasonic time and oxidation with hydrogen peroxide on carbon black （CB） particle size were discussed. The results showed that CB particle size decreased by mechanical agitation while it Increased by ultrasonic with the increase of CMC viscosity. Uitrasonk is a more effective method to disperse CB particles than that of mechanical agitation. CB particle size lbviously decreased with itcreasing ultrasonic time and arrived at about 160 nm for 60min.In addition,oxidation with 2 mol/L of H2O2 and 0.2wt% of CMC300 reduced CB particle size to 160nm at 90℃ for 2.5h.

Preparation of Carboxymethyl Cellulose Fibers

Carboxymethyl cellulose(CMC) fibers were produced by extruding the CMC solution into the metal salt coagulation bath and collected with a winding machine.It was found that copper chloride,ferric chloride,cerium chloride,lanthanum chloride and aluminum nitrate solution could be used as coagulation bath to prepare CMC fibers,whereas the metal salt solutions,such as nickel chloride,zinc chloride,calcium chloride and magnesium chloride,could not.The fiber formation is due to the coordination between the carboxylates of CMC and metal ion.Fourier transform infrared spectroscopy(FTIR) was applied to studying the coordination mode of CMC and metal ion.The metal salt concentration,pH value and temperature of the coagulation bath affect the tenacity and elongation of the fiber.CMC fibers show good water uptake ability and can adsorb water more than 200% of its own weight.The mechanical behaviors of CMC fiber show dependence on environment humidity.

Effect of mistletoe combined with carboxymethyl cellulose on dry eye in postmenopausal women

AIM： To investigate the protective effect of mistletoe combined with carboxymethyl cellulose eye drops on dry eye in postmenopausal women.METHODS： Sixty postmenopause female patients diagnosed of dry eye were assigned randomly to mistletoe combined with carboxymethyl cellulose eye drops treatment group（n=30） and control group treated with normal saline eye drops（n=30）. The subjective symptoms of ocular surface, Ocular Surface Disease Index（OSDI）, tear film function tests, tear protein and corneal morphology by confocal scanning microscopy were analyzed before treatment and at 1, 2, 4 and 8 wk after treatment respectively. To ensure the safety of the trial, all patients were examined with systolic pressure, diastolic pressure, glutamic-pyruvic transaminase, glutamic oxaloacetic transaminase, urine creatinine, and blood urea nitrogen at 8 wk after treatment.RESULTS： There were no obvious differences between two groups before the treatment（P〉0.05）. In two months after the treatment, the symptoms of ocular surface, OSDI, tear protein, and tear film function were only slightly changed in normal saline eye drops group. However, all indices were improved after the treatment of mistletoe combined with carboxymethyl cellulose eye drops group（P〈0.05）. In addition, the average amount of corneal epithelium basal cells and inflammatory cells of mistletoe treated group were 3174±379 and 38±25 cells/mm2, significantly decreased as compared to the control group with 4309±612 and 158± 61 cells/mm2, respectively. In the control group, althoughnerves still maintained straight under corneal epithelium, the number of nerves were significantly decreased, as compared with normal female. In the mistletoe treated group, the number of nerves was only slightly reduced, compared with normal female.CONCLUSION： Mistletoe combined with carboxymethyl cellulose eye drops can alleviate the symptoms and signs of dry eye symptoms.

Effect of Carboxymethyl Cellulose(CMC) Functionalization on Dispersion, Mechanical, and Corrosion Properties of CNT/Epoxy Nanocomposites

Carbon nanotube(CNT)/epoxy nanocomposites have a great potential of possessing many advanced properties.However,the homogenization of CNT dispersion is still a great challenge in the research field of nanocomposites.This study applied a novel dispersion agent,carboxymethyl cellulose(CMC),to functionalize CNTs and improve CNT dispersion in epoxy.The effectiveness of the CMC functionalization was compared with mechanical mixing and a commonly used surfactant,sodium dodecylbenzene sulfonate(Na DDBS),regarding dispersion,mechanical and corrosion properties of CNT/epoxy nanocomposites with three different CNT concentrations(0.1%,0.3%and 0.5%).The experimental results of Raman spectroscopy,particle size analysis and transmission electron microscopy showed that CMC functionalized CNTs reduced CNT cluster sizes more efficiently than Na DDBS functionalized and mechanically mixed CNTs,indicating a better CNT dispersion.The peak particle size of CMC functionalized CNTs reduced as much as 54%(0.1%CNT concentration)and 16%(0.3%CNT concentration),compared to mechanical mixed and Na DDBS functionalized CNTs.Because of the better dispersion,it was found by compressive tests that CNT/epoxy nanocomposites with CMC functionalization resulted in 189%and 66%higher compressive strength,224%and 50%higher modulus of elasticity than those with mechanical mixing and Na DDBS functionalization respectively(0.1%CNT cencentration).In addition,electrochemical corrosion tests also showed that CNT/epoxy nanocomposites with CMC functionalization achieved lowest corrosion rate(0.214 mpy),the highest corrosion resistance(201.031Ω·cm^(2)),and the lowest porosity density(0.011%).

Controllable Synthesis of Carboxymethyl Cellulose and Its Application in Tobacco Sheets

Carboxymethyl cellulose(CMC)with different degree of substitution(DS)was prepared by controlling feed ratio and times of alkalization and etherification.CMC with different molecular weight was prepared by degradation of hydrochloric acid solution.Orthogonal experiments were designed to study the effects of addition amount,molecular weight and DS of CMC on the tensile strength of tobacco sheets.The effects of CMC on the thermal properties and aerosol release of tobacco sheets were also studied.The results showed that the addition amount and the molecular weight of CMC had obvious effect on the tensile strength of tobacco sheets.The DS of CMC had no significant effect on the tensile strength of tobacco sheets.The addition of CMC improved the thermal stability of tobacco sheets to a certain extent,and had certain influence on the content of nicotine in aerosol.

Dyes adsorption using a synthetic carboxymethyl cellulose-acrylic acid adsorbent

Removal of noxious dyes is gaining public and technological attention. Herein grafting polymerization was employed to produce a novel adsorbent using acrylic acid and carboxymethyl cellulose for dye removal. Scanning electron microscopy and Fourier-transform infrared spectroscopy verified the adsorbent formed under optimized reaction conditions. The removal ratio of adsorbent to Methyl Orange, Disperse Blue 2BLN and malachite green chloride reached to 84.2%, 79.6% and 99.9%, respectively. The greater agreement between the calculated and experimental results suggested that pseudo second-order kinetic model better represents the kinetic adsorption data. Equilibrium adsorptions of dyes were better explained by the Temkin isotherm. The results implied that this new cellulose-based absorbent had the universaiity for removal of dyes through the chemical adsorption mechanism.

Crosslinked carboxymethyl cellulose-sodium borate hybrid binder for advanced silicon anodes in lithium-ion batteries

Silicon anodes have drawn ever-increasing attention in lithium-ion batteries(LIBs) owing to their extremely high theoretical capacity and abundance in the earth. Despite promising advantages, the wide use of silicon anodes in LIBs is highly hindered by their fast capacity fading and low Coulombic efficiency arising from their substantial volumetric variation(>300%). Herein, we report a novel aqueous hybrid gel binder for silicon anodes via crosslinking sodium carboxymethyl cellulose(NaCMC) by an inorganic crosslinker-sodium borate. Not only this gel polymer binder can chemically bond to silicon nanoparticle, but also the deformable framework of this crosslinked binder is capable of maintaining electrode integrity, thus buffering dramatic volume change of silicon. Consequently, the silicon anode with this gel binder exhibits good cycle life(1211.5 mAh/g after 600 cycles) and high initial Coulombic efficiency(88.95%).

Effects of molecular weight and concentration of carboxymethyl cellulose on morphology of hydroxyapatite nanoparticles as prepared with one-step wet chemical method

Nano-sized apatite particles （nAP） synthesized with carboxymethyl cellulose （CMC） have shown great application potentials in in situ heavy metal remediation. However, differences in CMC＇s properties effects on the size of nAP produced are not well understood. In this paper, two types of CMC, with respective molecular weights （MW） of-120000 and -240000 Dalton or respective polymerization degrees of 500 （CMC-500） and 1050 （CMC-1050）, were studied in a concentration range of 0.05%-0.5% （w/w） for nAP synthesis. Morphology of the particles was characterized with transmission electron microscopy （TEM）. Results showed that 0.05% CMC- 500 solution gave an average particle size o f 148.7 -4-134.9 rim, 0.25% CMC-500 solution produced particles of 21.8~20.4nm, and, 0.5% CMC-500 solution contained particles of 15.8-4-7.7nm. In comparison, 0.05% CMC- 1050 solution produced nanoparticles of 6.8~3.2 rim, 0.25% CMC-1050 produced smaller nAP of 4.3-1-3.2 nm, and 0.5% CMC-1050 synthesized the smallest nanoparti- cles in this study, with an average diameter of 3.0~2.1 nm. Chemical composition of the products was identified with X-ray diffraction （XRD） as pure hydroxyapatite. Interac- tions between nAP and CMC were discussed with help of attenuated total reflection Fourier transform infrared （ATR- FTIR） spectroscopic data. This study showed that CMC at higher concentration as well as higher MW facilitated to produce finer nanoparticles, showing that nAP size could be manipulated by selecting appropriate CMC MW and/or applying appropriate CMC concentration.

SYNTHESIS AND CHARACTERIZATION OF A SILICA-SUPPORTED CARBOXYMETHYLCELLULOSE PLATINUM COMPLEX AND ITS CATALYTIC BEHAVIORS FOR HYDROGENATI0N OF AR0MATICS

A silica-supported carboxymethylcellulose platinum complex (abbreviated as SiO_2-CMC-Pt) has been prepared and characterized by XPS. Its catalytic properties for hydro-genation of aromatic compounds were studied. The results showed that this catalystcould catalyze the hydrogenation of phenol, anisol, p-cresol, benzene and toluene to cyclo-hexanol, cyclohexyl methyl ether, p-methyl cyclohexanol, cyclohexane and methylcyclo-hexane, respectively in 100% yield at 30℃ and 1 atm. In the hydrogenation of phenol,COO/Pt ratio in SiO_2-CMC-Pt has much influence on the initial hydrogenation rate andthe selectivity for the intermediate product, cyclohexanone. The highest initial rate andthe highest yield of cyclohexanone both occur at COO/Pt ratio of 6. The complex is stableduring the reaction and can be used repeatedly.