Hybrid particles of polystyrene and carboxymethyl cellulose as substrates for copper ions

The synthesis of hybrid particles was carried out by emulsion polymerization of styrene in complexes formed by carboxymethyl cellulose (CMC), a polyanion, and a cationic surfactant, cetyltrimethylammonium bromide (CTAB). CMC chains with variable molecular weights and degrees of substitution were tested. The polymerization condition chosen was that corresponding to CMC chains fully saturated with CTAB and to the onset of pure surfactant micelle formation, namely, at the critical aggregation concentration. The hybrid particles were characterized by zeta potential and light scattering measurements. The period of colloidal stability in the ionic strength of 2.0 mol L(-)(1) NaCl was observed visually. Upon increasing the CMC chain length, the particle characteristics remained practically unchanged, but the colloid stability was increased. The increase in the CMC degree of substitution led to particles with more negative zeta potential values. The adsorption of copper ions (Cu(2+)) on the surface of hybrid particles could be described by the Langmuir model, as determined by potentiometric measurements. The increase in the mean zeta potential values and X-ray absorption near-edge spectra evidenced the immobilization of Cu(2+) ions on the hybrid particles.     

Removal of Toxic As (V) Ions by Adsorption onto Alginate and Carboxymethyl Cellulose Beads

The removal of arsenic ions from dilute aqueous solutions using biopolymeric beads of crosslinked sodium alginate and carboxymethyl cellulose (CMC) as the adsorbent is reported in this paper. The biopolymeric alginate and carboxymethyl cellulose beads were prepared and characterized by FTIR spectra. On the surfaces of the prepared beads were performed static and dynamic adsorption studies of arsenic ions at fixed pH and ionic strength of the aqueous metal ion solutions. The adsorption data were applied to Langmuir and Freundlich isotherm equations and various static parameters were calculated. The dynamic nature of adsorption was quantified in terms of several kinetic constants such as rate constant for adsorption (k₁) and Lagergreen rate constant (K_ad). The influence of various experimental parameters such as solid to liquid ratio, pH, temperature, presence of salts and chemical composition of biopolymeric beads were investigated on the adsorption of arsenic ions.     

Metal adsorption of carboxymethyl cellulose/carboxymethyl chitosan blend hydrogels prepared by Gamma irradiation

Blend hydrogels based on the carboxymethyl cellulose (CMC) and carboxymethyl chitosan (CMCts) were prepared by γ-irradiation of a high concentrated CMC/CMCts aqueous solution. Properties of the hydrogels, such as gel fraction, swelling ratio, gel strength, and metal adsorption for Pb and Au were investigated. The gel fraction increased with increasing dose, while the swelling ratio decreased with increasing it. The obtained blend hydrogels had high adsorption performance which was controlled by adjusting the composition of CMC/CMCts.     

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films

Patterns of the adsorption of bovine serum albumin on carboxymethyl dextran and carboxymethyl cellulose films are studied by means of microcontact printing, atomic force microscopy, and quartz crystal microbalance. It is shown that both the charge of polysaccharide macromolecules and the technique for deposition of their films onto the surface (via adsorption from a solution or covalent cross-linking) are factors that determine the degree of nonspecific adsorption of the protein on such films.     

Synthesis and characterization of <Emphasis Type="Italic">β</Emphasis>-cyclodextrin–carboxymethyl cellulose–graphene oxide composite materials and its application for removal of basic fuchsin

A novel β-cyclodextrin–carboxymethyl cellulose–graphene oxide composite material (β-CD–CMC–GO) was synthesized, and its application as excellent adsorbents was carried out for removal basic fuchsin (BF) in aqueous solution. The structure and morphology of β-CD–CMC–GO composite material were characterized by using FTIR, SEM, TEM, XRD, TG and DSC methods. The composites could remove basic fuchsin from aqueous solution efficiently. The adsorption experiment was carried out and the optimum experimental conditions were ascertained. The highest adsorption efficiency was obtained 97.3% at 0.015 g/mL dosage of β-CD–CMC–GO, the temperature of 25 °C and time of 2.5 h. Adsorption kinetics, adsorption isotherm and adsorption thermodynamic were used to analyze the adsorption system. The experimental data of adsorption kinetics of system were well followed by pseudo-second-order equation. The adsorption isotherm data were fitted using Langmuir isotherm model and Freundlich isotherm model. The maximum adsorption capacity of basic fuchsin reached 58.65 mg/g. The thermodynamic parameters indicated that the adsorption process was spontaneous and exothermic. The adsorbent has excellent regeneration ability and reproducibility. The proposed method shows that the β-CD–CMC–GO could be applied to removal of basic fuchsin in wastewater with satisfactory result.     

Calcium lignosulfonate adsorption and desorption on Berea sandstone

This paper describes adsorption and desorption studies carried out with calcium lignosulfonate (CLS) on Berea sandstone. Circulation experiments were performed to determine CLS adsorption isotherms and the effects of CLS concentration, temperature, salinity, brine hardness, and injection rate on adsorption density. Flow-through experiments were performed to assess the reversibility of CLS adsorption and the influence of postflush rate, brine concentration, brine hardness, brine pH, and temperature on the desorption process. Results indicate that CLS adsorption isotherms on Berea sandstone follow the Freundlich isotherm law. The results presented in this paper on the effects of CLS adsorption and desorption on Berea sandstone show that: (1) increasing CLS concentration and salinity increases CLS adsorption density; (2) increasing temperature will decrease adsorption density; (3) increasing injection rate of CLS solution will slightly decrease CLS adsorption density; (4) postflush rate and salinity of brine have a large impact on the CLS desorption process; (5) the adsorption and desorption process are not completely reversible; and (5) temperature and pH of the postflush brine have little effect on desorption.     

Integrated approaches for reducing sample size for measurements of trace elemental impurities in plutonium by ICP-OES and ICP-MS

A novel microsphere adsorbent based upon carboxymethyl cellulose sodium/prussian blue composite loaded with Lanthanum(III) (CMC/PB-La) was successfully synthesized via electrostatic ejection device for removal of cesium from contaminated water, and characterized by FT-IR, SEM, EDX and XPS. Influencing factors to adsorption cesium were investigated, including solution pH, adsorbent dosage, contact time, initial concentration, temperature and competing ions. Linear Freundlich isotherm was fitted satisfactorily to the adsorption data, and the adsorption kinetic data was fitted well with pseudo-second-order model. Moreover, the results of γ-irradiation experiments indicate that CMC/PB-La has good radiation stability.     

Magnetic chitosan functionalized with β‐cyclodextrin as ultrasound‐assisted extraction adsorbents for the removal of methyl orange in wastewater coupled with high‐performance liquid chromatography

Three types of choline chloride based deep eutectic solvents were prepared and used to modify magnetic chitosan. The adsorption capacity of the three deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin for removing methyl orange from wastewater was examined. The different deep eutectic solvents were used to strengthen the adsorption capacity of magnetic chitosan. Deep‐eutectic‐solvent‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin materials were characterized by Fourier transform infrared spectroscopy and Brunauer–Emmett–Teller surface area measurements. Among the three deep eutectic solvents, choline chloride/glycerol (1:2) modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin showed the highest adsorption capacity to methyl orange. Therefore, choline chloride/glycerol (1:3, 1:4, 1:5, 1:6) deep eutectic solvents were prepared for the assay, and choline chloride/glycerol‐modified magnetic chitosan/carboxymethyl‐β‐cyclodextrin prepared with choline chloride/glycerol (1:3) (volume: 40 μg, contact time: 30 min, and pH: 6) had the best adsorption capacity over the concentration range of 10–200 μg/mL.     

Adsorption and electrochemical studies on surfactant modified cellulose acetate membranes

The possibility of the modification of a cellulose acetate membrane upon adsorption of ionic surfactants, cetyl pyridinium chloride and sodium dodecyl sulphate has been investigated on the basis of membrane potential studies. For the estimation of the extent of adsorption, surface tension measurements were carried out in the presence and absence of cellulose acetate membrane using surfactant solutions of variable compositions. The results have also been used for the characterization of the thermodynamic equilibrium, which the membrane surfactant system attains upon surfactant adsorption, in terms of the immobilization constant. The text was submitted by the authors in English.     

Fabrication and characterization of CMC‐based magnetic superabsorbent hydrogel nanocomposites for crystal violet removal

In this research work, novel magnetic superabsorbent hydrogel nanocomposites (MSHNs) based on carboxymethyl cellulose were prepared via a facile “one‐pot” two step approach. Magnetic iron oxide nanoparticles were in situ synthesized and incorporated into carboxymethyl cellulose/poly(acrylic acid) polymer hydrogel. The morphology and chemical composition of MSHNs as well as the presence of magnetic iron oxide nanoparticles were evaluated by using Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X‐Ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of different reaction parameters on the swelling capacity of MSHNs was investigated. Furthermore, batch adsorption experiments of crystal violet dye onto MSHNs were studied by varying solution pH, initial dye concentration, and temperature. Evaluation of thermodynamic parameters of crystal violet adsorption confirmed that the adsorption was spontaneous and endothermic process in nature. The equilibrium study revealed that the dye adsorption behavior of MHSNs followed the Redlich‐Peterson isotherm model. Finally, the dye adsorption experiment data was well fitted by the pseudo‐second‐order kinetic model with the regression coefficient (R²) of 0.9979. Our results suggest that the MHSNs with facile preparation method, high swelling capacity, and high dye adsorption capacity may be used as promising adsorbents for fast removal of various dyes from aqueous solutions. Copyright © 2016 John Wiley & Sons, Ltd.     

羧甲基纤维素钠和甲基纤维素在ZrO_2微粉上的吸附作用及其对悬浮体稳定性的影响

研究了ZrO2微粉自水中对羧甲基纤维素钠（CMC）和甲基纤维素（MC）的吸附作用及对ZrO2水悬浮作稳定性的影响．结果表明：（1）CMC的吸附等温线为Langmuir型,CMC可能以较为舒展的方式单层吸附于ZrO2。表面,由于有电性吸引作用在pH3．4时的极限吸附量较pH7．0时的略大;（2）MC的极限吸附量远大于CMC的,MC分子可能以线团状吸附,吸附层厚度可达14～56nm;（3）难较大浓度时MC比CMC更易于使ZrO2悬浮作稳定．     

Processing of magnesium carbonate fines by dissolved-air flotation

Dissolved-air flotation of natural magnesite and dolomite fine particles (at the sub-sieve size range) was undertaken for their selective recovery. A commercial fatty acid was used as anionic collector in a batch cell, at different pH values. The application of modifiers, such as carboxymethyl cellulose, sodium hexametaphosphate and sodium pyrophosphate, was examined together with zeta-potential measurements. After the laboratory separation experiments with the pure salt-type minerals, the differential separation of artificial mixtures was carried out in the presence of modifiers, at the optimum conditions, to give promising results especially in reverse flotation of magnesite.     

Quartz crystal microbalance with dissipation monitoring and surface plasmon resonance studies of carboxymethyl cellulose adsorption onto regenerated cellulose surfaces

Adsorption of anionic polyelectrolytes, sodium salts of carboxymethyl celluloses (CMCs) with different degrees of substitution (DS = 0.9 and 1.2), from aqueous electrolyte solutions onto regenerated cellulose surfaces was studied using quartz crystal microbalance with dissipation monitoring (QCM-D) and surface plasmon resonance (SPR) experiments. The influence of both calcium chloride (CaCl(2)) and sodium chloride (NaCl) on CMC adsorption was examined. The QCM-D results demonstrated that CaCl(2) (divalent cation) caused significantly greater CMC adsorption onto regenerated cellulose surfaces than NaCl (monovalent cation) at the same ionic strength. The CMC layers adsorbed onto regenerated cellulose surfaces from CaCl(2) solutions exhibited greater stability upon exposure to flowing water than layers adsorbed from NaCl solutions. Both QCM-D and SPR results showed that CMC adsorption onto regenerated cellulose surfaces from CaCl(2) solutions increased with increasing CaCl(2) concentration up to the solubility limit (10 mM). Voigt-based viscoelastic modeling of the QCM-D data indicated that the CMC layers adsorbed onto regenerated cellulose surfaces had shear viscosities of η(f) ≈ 10(-3) N·s·m(-2) and elastic shear moduli of μ(f) ≈ 10(5) N·m(-2). Furthermore, the combination of SPR spectroscopy and QCM-D showed that the CMC layers contained 90-95% water. Adsorption isotherms for CMCs in CaCl(2) solutions were also obtained from QCM-D and were fit by Freundlich isotherms. This study demonstrated that CMC adsorption from CaCl(2) solutions is useful for the modification of cellulose surfaces.     

Synthesis of a cellulose derivative for enhanced sorption and selectivity of uranium from phosphate rocks prior to its fluorometric determination

In this research work, the separation of Uranium from phosphate medium via adsorption prior to its fluorometric determination was carried out onto a newly synthesised adsorbent made via impregnation of urea onto cellulose (UIC). The full characterisation of the synthetic extractant (UIC) was carried out by various instrumental techniques such as elemental analysis, FTIR, TGA, XRD and SEM analysis. Various factors that may affect the quality of adsorbing U (VI) ions using synthesised Urea-impregnated cellulose had been investigated. The maximum adsorption capacity (82 mg/g) for U (VI) has been verified by the Langmuir isotherm model. The thermodynamics and kinetics of the adsorption process indicated that the uranium sorption onto synthesised Urea-impregnated cellulose was an exothermic and pseudo-second-order process. The tolerance limits for the common cations which are actually found with uranium in the phosphate solutions and may show sorption behaviour on the synthesised UIC resin were calculated and gave a high tolerance limit. Contrary to previously reported studies, several ameliorations have resulted including an elevated selectivity and adsorption capacity of uranium from phosphate medium. The optimised method was applied with good accuracy results for determination of uranium in reference and different phosphate rock types bearing uranium.     

Comparison of hydroxypropyl and carboxymethyl guar for the preparation of nanocellulose composite films

The gas barrier and mechanical properties are crucial parameters for packaging materials, and they are highly correlated to the molecular interactions in the polymer matrix. To improve these properties of TEMPO-oxidized cellulose nanofibers (TOCNs) composite films, we studied the effect using hydroxypropyl guar (HPG) or carboxymethyl guar (CMG) in the preparation of TOCN composite films, which were made by following the solution-casting method. The subsequent film characterizations were carried out by UV–Vis spectra, scanning electron microscopy, oxygen and water vapor permeability measurements, tensile and thermogravimetric analyses. SEM results showed that CMG-based films had denser structures than their HPG counterparts. Moreover, the improved hydrogen bonding of the CMG-based films was partially responsible for the improved gas barrier performance, tensile strength and thermal stability. These results support the conclusion that CMG had advantages over HPG when used in the preparation of TOCNs packaging composite films.     

交联羧甲基红薯淀粉降低水中Ca~(2+)含量的研究

以环氧氯丙烷为交联剂,氯乙酸为羧甲基化试剂,合成交联羧甲基红薯淀粉并且研究其降低水中的Ca2+含量的效果.结果显示,交联羧甲基红薯淀粉吸附ca2+的适宜条件为,淀粉取代度0.721、2%淀粉用量、pH 8,吸附时间30min、吸附温度70℃下,交联羧甲基红薯淀粉对水中Ca2+的吸附量可达4.53mmol/L,Ca2+清除率为75.33%.交联羧甲基红薯淀粉吸附Ca2+的行为遵从Langmuir等温吸附方程.     

Direct filature of bacterial cellulose from culture medium

The continuous Filature of bacterial cellulose has been achieved directly from culture medium using shallow culture pan newly designed. A remarkable progress of fiber properties was observed comparing with regenerated cellulosic filaments on the filament of bacterial cellulose dependently on the rinsing process with water or ethylene glycol. The progress of fiber properties was also shown on the filament of N-acetylglucosamine(GlcNAc) incorporated bacterial cellulose probably due to enforcement of fiber interactions. A copolymer of carboxymethylglucose (CM-Glc) and glucose has been achieved successfully to increase the adsorption capacity for lead ion comparing with original carboxymethyl cellulose (CMC).     

Homogenous Carboxymethylation of Cellulose in the New Alkaline Solvent LiOH/Urea Aqueous Solution

In this work, the carboxymethylation of cellulose in a new alkaline cellulose solvent, LiOH/urea aqueous solution, was investigated. Carboxymethyl cellulose (CMC) samples were characterized with FT-IR, NMR, HPLC, and viscosity measurements. Water-soluble CMC with DS = 0.36∼0.65 was prepared, from both Avicel cellulose and cotton linters in the LiOH/urea system. The total DS of CMC could be controlled by varying the molar ratio of reagents and the reaction temperature. The results from structure analysis by HPLC after complete depolymerization showed that the mole fractions of the different carboxymethylated repeating units as well as those of unmodified glucose follow a simple statistic pattern. A distribution of the carboxymethyl groups of the AGU was determined to be in the order O-6 > O-2 > O-3 position at the level.     

微波辅助细菌纤维素酯的制备及对Pb(Ⅱ)的高效去除

以细菌纤维素(BC)为原料,通过微波辅助酯化改性的方法制得了两种改性细菌纤维素,细菌纤维素黄原酸酯(XMBC)和细菌纤维素硫酸酯(SMBC)。对所制备的样品进行X射线衍射(XRD)、扫描电镜-电子能谱(SEM-EDS)、傅里叶变换红外(FT-IR)光谱和BET比表面积分析,通过续批式实验考察其对Pb(Ⅱ)的去除效果。研究了pH值、反应时间、温度、污染物初始浓度、离子强度对其吸附能力的影响以及材料再生性能。结果表明,改性细菌纤维素的比表面积和孔容均有上升,其对Pb(Ⅱ)的吸附量随反应温度和离子强度的增加而降低,最优pH值为5.0。巯基的引入增强了细菌纤维素对Pb(Ⅱ)的吸附能力,改性后的吸附剂显示出比原始BC更优异的吸附性能,其中XMBC和SMBC的最大吸附量分别为144.93和126.58 mg·g^-1,该吸附过程符合准二级速率方程和Langmuir等温吸附模型。材料对Pb(Ⅱ)的吸附是自发的放热过程,且吸附剂易于再生和重复回收。因此, SMBC和XMBC作为从水中富集分离重金属的新型材料具有及大应用前景。     

Investigation of micro-immobilised enzyme reactors containing endoglucanases for efficient hydrolysis of cellodextrins and cellulose derivatives

Cellulases hydrolysing the interior parts of cellulose, also called endoglucanases, were immobilised in micro-immobilised enzyme reactors (μIMER) made of porous silicon with the purpose of investigating the use of such μIMERs for hydrolysis of cellodextrins and soluble cellulose derivatives. The endoglucanases Trichoderma reesei Cel 12A (TrCel 12A) and Bacillus agaradhaerens Cel 5A (BaCel 5A) were covalently coupled to the surface of a silicon microchip through Schiff base formation. For characterisation cellohexaose was used as substrate for the immobilised enzymes. The characteristics of the μIMER were investigated by studying the product formation when varying the concentration, flow-rate, temperature and pH of the substrate solution. Hydrolysis was performed in the μIMER connected on-line to a chromatographic system, where the products were separated and detected using high-performance anion exchange chromatography (HPAEC) coupled to pulsed amperometric detection (PAD). A comparison of the hydrolytic pattern between BaCel 5A and TrCel 12A was carried out and the results show that the two investigated endoglucanases give specific hydrolytic patterns in the products formed that provide important information about the enzymes. The μIMERs are robust and can be employed continuously over a period of at least several days. Moreover, on appropriate storage, no activity loss is seen after 60 days. The ability of the BaCel 5A containing μIMER to perform hydrolysis of derivatised cellulose was also investigated using carboxymethyl cellulose (CMC) as substrate. Separation and detection were carried out using size exclusion chromatography (SEC) with refractive index detection (RI). The results show that the μIMERs are robust and can be employed for on-line hydrolysis of both cellodextrins and derivatised cellulose of high molecular weight.