Adsorption Of Rb Research Articles

Assessment and development of carbonaceous soot from wood burning process: adsorption, kinetics and thermodynamics study for Rhodamine B dye

Carbon based materials have acquired pivotal importance in the recent era for the removal of pollutants from the effluents. In this study, wooden soot (WS) obtained from wood burning has been utilized as an adsorbent for the removal of Rhodamine B dye (RB). The adsorption of RB on WS was studied as function of the contact time, concentration, and temperature. The amount of dye adsorbed onto the WS increased with the increase in the contact time, concentration and temperature. The adsorption data fitted well in Langmuir and Freundlich models with comparatively greater R2 value for the Langmuir model. Adsorption data followed the pseudo second order kinetics. The uptake of dye by the adsorbent was 238 mg/g. The various Thermodynamic parameters such as ∆Ho­, ∆So and ∆Go were studied which indicated that the adsorption of RB on WS adsorbent remained a spontaneous endothermic process. The surface morphology was studied through FESEM before and after the adsorption of RB, which indicated accumulation of dye on to the small pores. The functional group analysis was performed through FT-IR which indicated a clear change at 2360 cm-1 after the adsorption which confirmed the adsorption phenomena. The pore size, pore volume and pore diameter were 47.44 m2/g, 0.07 cm3/g and 35.23 A0 respectively. This study will highly acknowledge the use of low cost adsorbent materials for the environmental remediation.

Hydrothermal deposition of titanate on biomass carbonaceous aerogel to prepare novel biomass adsorbents for Rb+ and Cs+

Biomass adsorbents derived from pomelo peels were synthesized by modifying biomass carbonaceous aerogels (BCA) and carbonized biomass carbonaceous aerogels (CBCA) with sodium titanate and potassium titanate through a hydrothermal deposition process. The prepared adsorbents were characterized by SEM, XRD, FTIR, TG-DTG, BET isotherm, XPS, and then used for the adsorption of Rb+ and Cs+ from the aqueous solutions. The effects of ion concentration, contact time, temperature, solution pH and ionic strength on the adsorption of Rb+ and Cs+ were investigated systematically. In addition, the adsorption kinetics and isotherms were studied and the adsorption data were better fitted with pseudo-second-order kinetics and Langmuir adsorption isotherm models, respectively. The characterization and adsorption data proved that the prepared adsorbents had excellent adsorption properties for Rb+ and Cs+ from the aqueous solutions. The maximum adsorption amounts of Rb+ and Cs+ are 1.84 and 1.60 mmol/g, respectively. From the analysis of adsorption mechanism, the ion exchange reaction could occur between Na+ of sodium titanate or K+ of potassium titanate on the adsorbents and Rb+ or Cs+ in the solution which enhanced the adsorption existed on the surface of adsorbents.

Novel Biomass‐Derived Adsorbents Grafted Sodium Titanium Silicate with High Adsorption Capacity for Rb+ and Cs+ in the Brine

AbstractTwo biomass‐derived adsorbents (BCA@STS, CBCA@STS) modified with sodium titanium silicate (STS) were synthesized through a hydrothermal deposition method and tested to adsorb Rb+ and Cs+ from aqueous solution and brine. The BET characterization results showed that the adsorbents had mesoporous structures and excellent adsorption capacity for Rb+ and Cs+ with the maximum adsorption amounts as high as 2.07 mmol g−1 and 1.47 mmol g−1, respectively. XRD and XPS analyses of the adsorbents before and after adsorption revealed that the high adsorption capacity is attributed to the Na+ located in the adsorbents and ion exchange between Na+ and Rb+ or Cs+ is the key mechanism. The chemical composition of functional substance is the mixture of (HNa)O⋅SiO2⋅2TiO2⋅2H2O and Na2Ti3O7. The adsorption amounts increase with increasing of pH, and decrease with the increase of NaCl concentration due to the competitive adsorption between H+/Na+ and Rb+/Cs+. The adsorption kinetics of both these two adsorbents were well fitted to the pseudo‐second order kinetic model indicating that the chemisorption was dominant throughout the adsorption process. Apart from the excellent adsorption properties of Rb+ and Cs+ from aqueous solution, both BCA@STS and CBCA@STS can be used for the adsorption of Rb+ and Cs+ from the brine, and the maximum adsorption rate is up to almost 100%, showing promising application for extracting of Rb+ and Cs+.

Plant-mediated synthesis of Cu0.5Zn0.5Fe2O4 nanoparticles using Minidium leavigatum and their applications as an adsorbent for removal of reactive blue 222 dye

Cu0.5Zn0.5Fe2O4 magnetic nanoparticles were synthesized using Minidium leavigatum extract and required metal salts by a green method. This method has some benefits such as nontoxic, economic viability, ease to scale up, less time consuming and environmental friendly approach for the synthesis of Cu0.5Zn0.5Fe2O4 magnetic nanoparticles without using any hazardous organic chemicals. The sample was characterized by powder x-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), energy dispersive x-ray analysis (EDX), and Brunauer–Emmett–Teller (BET) surface area analysis. The environmentally friendly synthesized nanoparticles were used as adsorbent for removal of reactive blue 222 (RB 222) dye from aqueous solutions. The effects of initial dye concentration and nanoparticle dosage on dye adsorption were assessed. Adsorption equilibrium studies were investigated to determine the adsorption capacity of the adsorbents by using the Langmuir and Freundlich isotherm models. The Langmuir model yielded more suitable than the Freundlich model for the adsorption of RB 222 on Cu0.5Zn0.5Fe2O4 magnetic nanoparticles. Adsorption kinetics obeyed a pseudo second-order kinetic model.

Tunable superporous magnetic adsorbent prepared via eco-friendly Pickering MIPEs for high-efficiency adsorption of Rb+ and Sr2+

Until recently, high organic phase volume and the addition of a large amount of surfactants have been two major disadvantages of conventional high internal phase emulsions (HIPEs) templates in the construction of porous adsorbents. Herein, a facile and novel tunable superporous magnetic adsorbent (MSPA) was synthesized by the polymerization of the green surfactant-free (soybean oil)-in-water Pickering medium internal phase emulsion (O/W Pickering MIPEs), which was stabilized synergically by the magnetic yeast (MY) and chitosan (CTS). It is interesting that the extremely stable surfactant-free Pickering-MIPEs can be obtained through the fine synergistic effect between MY and CTS at the oil-water interface, and the pore structure of the magnetic adsorbent can be easily adjusted by changing the ratio of MY to CTS, as well as the external pH. The obtained MSPA with abundant COO− and NH2 functional groups had a fast capture rate and high adsorption capacities for radioactive Rb+ and Sr2+ ions, respectively. The saturation adsorption capacities of 168.98 and 151.91 mg/g for Rb+ and Sr2+ can be achieved within 25 or 10 min, respectively. Moreover, the MSPA had excellent regeneration ability and reusability. This work provided a feasible and environmentally friendly pathway for preparation of the superporous magnetic adsorbent with tunable porous structure for adsorption and separation application.

Simultaneous adsorption of Li(I) and Rb(I) by dual crown ethers modified magnetic ion imprinting polymers

With the gradual exhaustion of land mineral resources, oceans and lakes have attracted world attention because they are abundant in inorganic mineral resources including lithium, potassium, rubidium and cesium. Lithium is becoming the key material in manufacturing of primary and secondary batteries used in various portable devices and hybrid/electric vehicles. Rubidium has been widely applied inglobal positioning satellites, magneto‐optic modulators, solid‐state lasers, phosphors, and glass manufacturing. In this work, a novel dual‐functional magnetic ion imprinting polymer (Fe3O4@SiO2@IIPs) powder was prepared using 12‐crown‐4 (12C4) and 18‐crown‐6 (18C6) as functional monomer, and characterized by FT‐IR, elemental analysis, XRD, TGA, SEM and TEM. The adsorption performance of Fe3O4@SiO2@IIPs for simultaneous adsorption of lithium and rubidium from simulative salt lakes was evaluated by batches of experiments at various pH values, contact time, and initial concentrations. Kinetic experiments show that the adsorption process followed the pseudo second order kinetic model. Langmuir adsorption isotherm model and Freundlich adsorption equilibrium data were fitted; the results show that Langmuir isotherm model is more suitable for the adsorption process. Additionally, Fe3O4@SiO2@IIPs exhibit specificity towards Li(I) and Rb(I) and low competitive behavior with Na(I), K(I) and Mg (II). Additionally, the selectivity properties, reusability and adsorption thermodynamic were also investigated. The obtained results show that the prepared Fe3O4@SiO2@IIPs material remains high adsorption capacities after five cycles, exhibits excellent abilities to simultaneously and selectively recover Li+ and Rb+ and have a promising application in the simultaneous adsorption of lithium and rubidium ions.

Strontium residual salt analyses (SrRSA) and geochemistry of Bakken Formation core samples from Fleckton 1-20, North Dakota

Samples of Bakken Formation core from the Fleckton 1-20 well in Ward County, North Dakota, were analyzed using the Strontium Residual Salt Analysis (SrRSA) method to assess pore-water communication among the upper, middle, and lower sections of the unit by analyzing 87Sr/86Sr in pore-water salts leached from the core. Major and trace element analyses were also conducted on bulk-rock samples and leachates (Elemental Residual Salt Analysis or ERSA). The middle part of the Bakken Formation, a calcareous and dolomitic siltstone to fine sandstone, is encased between two black shales—the upper and lower sections of the formation. These units are informal and herein named the upper, middle, and lower Bakken members. Strontium isotope measurements and concentration of some solutes in leachates indicate that pore water in the black shale of the upper Bakken member has remained isolated from pore water in the middle Bakken member except for within a few feet immediately near the contact where elemental profiles indicate diffusive mixing. The SrRSA 87Sr/86Sr values from the middle Bakken member are consistent with produced water collected from 28 wells in Montana and North Dakota. In contrast to the similarity in 87Sr/86Sr values, ratios of concentrations such as K/Rb, Ca/Sr, Ca/Mg, and Na/Cl are slightly different between the pore-water leachates and produced water values. The differences in K/Rb and Ca/Sr are probably due to selective adsorption of Rb leading to larger K/Rb ratios and minor dissolution of carbonate minerals leading to larger Ca/Sr ratios in the leachates.

Interconnected superporous adsorbent prepared via yeast-based Pickering HIPEs for high-efficiency adsorption of Rb+, Cs+ and Sr2+

High internal phase emulsions (HIPEs) template method is an emerging effective method of fabricating high-efficiency, orderly porous polymer adsorbents, but the conventional HIPEs template requires harmful surfactants, so the development of surfactant-free green emulsion templates become the subject of great significance. Herein, we prepared a green surfactant-free oil-in-water (O/W) Pickering HIPEs stabilized solely with non-toxic caustic-pretreated yeast (P-Yeast), and used it as template to prepare a novel adsorbent (P-Yeast-PAA) with interconnected superporous structure by a one-step solution polymerization of acrylic acid (AA) monomers in the emulsion. Interestingly, the surfactant-free Pickering-HIPEs exhibited superior stability due to the fine affinity between P-Yeast and AA monomer, and the pore structure of the adsorbent can be easily regulated by changing the contents of the monomer or the particles used for stabilizing the emulsion. In addition, the adsorbents prepared from P-Yeast based emulsion template have interconnected pore structure, which are significantly superior to other Pickering-HIPEs templates which are hard to form a similar pore structure. The open-cell superporous adsorbent containing a large number of COO− functional group has a fast capture rate and strong adsorption capability for radioactive Rb+, Cs+ and Sr2+ ions, and the saturated adsorption capacities are 179.69 mg/g (2.10 mmol/g), 229.52 mg/g (1.73 mmol/g) and 166.81 mg/g (1.90 mmol/g), and the equilibrium adsorption time are 30, 40 and 20 min, respectively. The porous adsorbent also has excellent regeneration ability and reusability, and maintains a high adsorption capacity after repeated use of five adsorption-desorption cycles. This study provides an environmentally-friendly and promising strategy for fabricating the interconnected superporous adsorbent for adsorption removal of radioactive metal ions.

Description of heterogeneity of the sorbent surface on the basis of adsorption kinetic data

The kinetics of adsorption of Rb+ and Cs+ ions on different non-polarized and polarized active carbons at temperatures of 25, 35, 45, and 65 °C was investigated. The obtained results were processed using the equations of the pseudo-first- and pseudo-second-order models. The pseudo-second-order model better describes the adsorption of alkaline metal ions on the carbons studied. The kinetic dependences of three types reflecting heterogeneity of the sorbent surface were revealed on the basis of the theoretical analysis of sorption systems.

Enhancement of Rb+ and Cs+ removal in 3D carbon aerogel-supported Na2Ti3O7

In this paper, three-dimensional carbon aerogel (CA) combined sodium titanate (CA/Na2Ti3O7) was synthesized via a facile hydrothermal method, which was applied to remove Rb+ and Cs+ from aqueous solution. It is found the CA/Na2Ti3O7 composites have larger adsorption capacity and faster adsorption equilibrium time than that of pure Na2Ti3O7, which is ascribed to the enhanced effect of CA on Na2Ti3O7. The adsorption isotherms can be fitted by the Langmuir model well. The adsorption mechanism at pH < 8.0 is attributed to the ion exchange process, while inner-sphere surface complexation is predominant at pH > 8.0. The adsorption kinetics follows the pseudo-second-order model and the major mechanism is identified by Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy analyses. The adsorption of Rb+ and Cs+ on CA/Na2Ti3O7 can be explained by the ion exchange between Rb+/Cs+ and Na+ in the interlayer of Na2Ti3O7 and the complexation of Rb+/Cs+ with the –OH functional groups of CA/Na2Ti3O7. These results show potential application of CA/Na2Ti3O7 in the elimination of radionuclides from wastewater.

Fabrication of porous adsorbent via eco-friendly Pickering-MIPEs polymerization for rapid removal of Rb+ and Cs+

A novel carboxymethylcellulose-g-poly(acrylamide)/montmorillonite (CMC-g-PAM/MMT) hybrid adsorbent with sufficient interconnected pores was prepared via the Pickering medium internal phase emulsions (MIPEs) polymerization using eco-friendly inolenic acid oil (IAO) as the disperse phase and MMT as the stabilized particles. The effects of the dosages of MMT and Pluronic F68 on the pore structures were studied. It was found that the well-defined pore structure was obtained when the amounts of MMT and Pluronic F68 were 2% and 6%, respectively. The FTIR spectra analysis showed that MMT participates in the polymerization reaction. The porous adsorbent can rapidly reach adsorption equilibrium within 30 min, with the maximum adsorption capacities of 177.90 mg/g for Rb+ and 265.93 mg/g for Cs+. The fitting results confirmed that chemisorptions play a crutial role in the adsorption process, and the complexation of COO− and Rb+ or Cs+ was the main driving force for adsorption. Cyclic adsorption experiment results in static and fixed bed column show that the porous adsorbent can be recycled for the adsorption of Rb+ and Cs+ ions. The new porous adsorbent has the potential for rapid adsorption and removal of metal ions such as radioactive Rb+ and Cs+.

Effects of impurity adsorption on topological surface states of Bi2Te3

Electronic structures of Bi2Te3 with adsorption of Rb, In, Ga and Au atoms are studied by using the first-principle method, focusing on the effect of non-magnetic impurities on the topologically protected surface states. Upon monolayer formation, the bulk conduction band is moved down to the Fermi level with a significant Rashba splitting due to n-doping behavior with band modification details depending on the adatom chemistry. Our study shows the robustness of the intrinsic spin-momentum coupled surface band and emergence of a new similar one, which could provide helpful insight for developing novel spintronic devices.

Fabrication of a magnetic porous hydrogel sphere for efficient enrichment of Rb+ and Cs+ from aqueous solution

A series of magnetic porous hydrogel spheres were prepared from the oil in water (O/W) Pickering emulsion stabilized with silicone-modified magnetic attapulgite (MAPT), using hydroxypropyl cellulose (HPC) as the grafting backbone and acrylic acid (AA) as the monomer. The structure, morphologies and physico-chemical features of the Pickering emulsions and the hydrogel spheres were characterized by TEM, SEM, XRD and TGA techniques. The results revealed that the Fe3O4 was attached on the surface of APT with good dispersion, and the magnetic APT (MAPT) was modified successfully with silane. The emulsion with HPC, AA, initiator and crosslinker inside can be directly dropped into hot liquid paraffin to form hydrogel sphere. The rod-like APT as the stabilizer facilitated to form open pore and interconnected pores. The magnetic porous hydrogel sphere can rapidly adsorb the rare elements Rb+ and Cs+, with the maximum adsorption capacities of 232.46 and 239.88mg/g, respectively. The adsorbed Rb+ and Cs+ ions can be recovered by a simple desorption process, and the hydrogel sphere also showed excellent reusability after five consecutive adsorption–desorption cycles. This porous sphere with excellent adsorption capability and rate is potential adsorbent for the adsorption and enrichment of rare metals Rb+ and Cs+.

Fast and high-capacity adsorption of Rb+ and Cs+ onto recyclable magnetic porous spheres

A novel recyclable magnetic porous sphere adsorbent is prepared by grafting acrylic acid (AA) onto hydroxypropyl cellulose (HPC) through a Pickering emulsion integrated precipitation polymerization and used for the enrichment of scattered strategic metals Rb+ and Cs+. The modified Fe3O4 nanoparticles can not only stabilize the Pickering emulsion template for forming pores, but also make the adsorbent easy to be separated from solution by magnetic field. The adsorption results indicate that the adsorption of Rb+ and Cs+ by the sphere adsorbent rapidly reaches equilibrium within 15 and 30min, respectively. The saturated adsorption capacities reach 310 and 448mg/g for Rb+ and Cs+, respectively, which are better than that reported in most of literatures. Fourier transform infrared spectra (FTIR) and X-ray photoelectron spectroscopy (XPS) analyses confirm that the chemical complexation of –COO− and –OH with Rb+ and Cs+ contribute mainly to the adsorption. In addition, the adsorbent is very easy to be recovered and regenerated, and the adsorption capacity does not decrease significantly even after five consecutive adsorption–desorption cycles, as compared with the initial adsorption capacity. The results of dynamic adsorption experiments show that the flow rate, initial ion concentration and column height have an effect on the adsorption capacities of Rb+ or Cs+. In a word, this recyclable sphere adsorbent is promising to be used for the efficient adsorption and enrichment of rare metals.

Sorption of Congo red and reactive blue on biomass and activated carbon derived from biomass modified by ionic liquid

Ionic liquid modified sorbent materials derived from peanut shell were prepared and used in the sorption of Congo red (CR) and reactive blue 4 (RB) dyes from aqueous solution. 1-methyl-3-decahexyl imidazolium ionic liquid (IL) was used to modify peanut shell (NS) and activated carbon (AC) from NS, to produce IL modified peanut shell (ILNS) and IL modified AC (ILAC), respectively. The adsorbents were characterised by fourier transform infrared (FTIR), Brunauer−Emmett−Teller (BET), x-ray diffraction (XRD), thermal gravimetric analysis (TGA) and scanning electron microscopy (SEM). The effects of sorbent dosage, initial solution pH and contact time (min) were evaluated. Adsorption was pH dependent, the modified materials (ILNS and ILAC) showed improved adsorption capacities of 136.4 and 150.0mgg−1 for CR and 290.0 and 364.4mgg−1 for RB respectively. Adsorption followed pseudo-second order. Also, adsorption of CR and RB onto ILAC followed the Freundlich isotherm, while ILNS was described by Freundlich and Langmuir.

Mineralogy and biogeochemistry of potassium in the Skogaby experimental forest, southwest Sweden: pools, fluxes and K/Rb ratios in soil and biomass

Clay minerals and K feldspars were evaluated as sources of K in a Norway spruce stand (Picea abies (L.) Karst.) from the Skogaby experimental forest in southwest Sweden. The soil, developed in a Quaternary glacial till, has only 3–5% clay, and more than 95% of its K resides in feldspars. Ratios of K/Rb were assessed in interlayers of 2:1 clay minerals (extracted with hot (100 °C) 2 M HCl), biomass and the forest floor. These compartments had similarly low K/Rb ratios, whereas K feldspars were significantly poorer in Rb. A fractionation model indicated preferential retention of Rb in the biomass and forest floor, due to stronger adsorption of Rb than K in the humus, as well as preferential uptake of K from the exchange complex in the mineral soil. Preferential uptake of K may result from weaker adsorption of K by the cation exchanger, or preference for dissolved K over Rb by the roots. A quantitative mineralogical analysis revealed that loss from micas may account for half of the Holocene loss of K from the soil, which was approximately 22 Mg ha−1. Exceptionally low K/Rb ratios in HCl extracts of the upper 60 cm of the profile indicated extensive loss of K from mica in the parent material and re-fixation of K and Rb at lower ratios. The results indicate that fixation in and release from clay minerals may be prominent in the cycling of K, even in a soil that is poor in clay minerals.

Surface Charge of the Calcite (104) Terrace Measured by Rb+ Adsorption in Aqueous Solutions Using Resonant Anomalous X-ray Reflectivity

Adsorption of Rb+ on the (104) plane of single crystal calcite was investigated to estimate the charge of the ionic crystal calcite–water interface. The adsorbed Rb+ coverage was quantified as a function of Rb concentration (1–100 mM) in calcite-saturated solutions at pH 8.3 by using in situ resonant anomalous X-ray reflectivity in transmission cell geometry. The Rb+ coverages for all solution conditions were small with the maximum ion coverage (Γmax) of 0.12(4) Rb+/nm2 estimated by the best-fit Langmuir isotherm model. This result provides an estimate of the upper limit to the effective surface charge density of about −0.02 C/m2 considering that any Rb+ adsorption to the terrace plane is likely induced by electrostatic attraction. This charge density is significantly lower (by a factor of ≥10) than those estimated from macroscopic measurements, implying that any excess charge likely originates from surface defects.

Efficient removal of Reactive Black from aqueous solution using polyaniline coated ligno-cellulose composite as a potential adsorbent

Polyaniline coated ligno-cellulose composite (PLC) was synthesised via in-situ polymerisation of aniline monomer and used for the removal of Reactive Black 5 (RB-5) from aqueous solutions. The adsorbent was characterised before and after adsorption to verify that the dye was indeed adsorbed. The removal occurred through the surface adsorption of RB 5 onto the PLC as identified from the Fourier transform infrared spectra, X-ray diffraction spectra and SEM image. Sorption kinetics were very fast and equilibrium was reached within 60 and 120min of interaction for initial concentrations of 50mg/L and 100mg/L, respectively. Kinetic studies revealed that the pseudo-second-order model described the sorption process better than the pseudo-first-order model and intra-particle diffusion was identified as the rate-limiting step. The equilibrium adsorption isotherm studies also revealed that the Langmuir isotherm provided the best fit with monolayer adsorption capacity of 312mg/g. The adsorption process was spontaneous and endothermic. Up to 98% desorption of the dye was also achieved using a 1:1 water:acetone mixture and this desorption efficiency could be achieved over four adsorption–desorption cycles. Single-stage batch adsorber studies confirmed that the maximum quantity of adsorbent required to achieve 95% removal of the dye was 20.41kg.

Rb+ Adsorption at the Quartz(101)–Aqueous Interface: Comparison of Resonant Anomalous X-ray Reflectivity with ab Initio Calculations

Adsorption of Rb+ to the quartz(101)–aqueous interface at room temperature was studied with specular X-ray reflectivity, resonant anomalous X-ray reflectivity, and density functional theory. The interfacial water structures observed in deionized water and 10 mM RbCl solution at pH 9.8 were similar, having a first water layer at height of 1.7 ± 0.1 Å above the quartz surface and a second layer at 4.8 ± 0.1 Å and 3.9 ± 0.8 Å for the water and RbCl solutions, respectively. The adsorbed Rb+ distribution is broad and consists of presumed inner-sphere (IS) and outer-sphere (OS) complexes at heights of 1.8 ± 0.1 and 6.4 ± 1.0 Å, respectively. Projector-augmented planewave density functional theory (DFT) calculations of potential configurations for neutral and negatively charged quartz(101) surfaces at pH 7 and 12, respectively, reveal a water structure in agreement with experimental results. These DFT calculations also show differences in adsorbed speciation of Rb+ between these two conditions. At pH 7, the lowest energy structure shows that Rb+ adsorbs dominantly as an IS complex, whereas at pH 12 IS and OS complexes have equivalent energies. The DFT results at pH 12 are generally consistent with the two site Rb distribution observed from the X-ray data at pH 9.8, albeit with some differences that are discussed. The surface charge estimated on the basis of the measured total Rb+ coverage was −0.11 C/m2, in good agreement with the range of the surface charge magnitudes reported in the literature.

Study on adsorption properties of QCS/PS-G8-2-8 anion exchange membrane for Rhodamine B

A series of novel anion exchange composite membrane (QCS/PS-G8-2-8) were synthesized based on the quaternized chitosan (QCS, DQ=89.20 (±3.50)%) blended with block polymer of polystyrene (PS) and G8-2-8 (maleic acid diethyl brace base pairs [octyl dimethyl chloride/ammonium bromide]). Then the QCS was cross-linked by glutaraldehyde (GA). The parameters including adsorption time (t), pH, and initial concentration of Rhodamine B (C0), temperature (T), the mass fraction of G8-2-8 and GA (WGA) on the adsorption were investigated to determine the optimum condition for the removal of RB. The kinetic and thermodynamic properties of the adsorption process were also discussed. The optimum adsorption condition was that the adsorption time was 100min, pH was 4, the initial concentration of RB was 100mgL−1, the mass fraction of G8-2-8 was 5.0wt%, the mass fraction of GA was 2.0wt%, the temperature was 40°C. Thus, RB optimum adsorption capacity (q) of the composite membrane QCS/PS-G8-2-8 (5.0%) (G8-2-8 mass content (wt.%) was 5.0%) was 17.04mgg−1. The adsorption isotherm of the RB on the composite membrane can be well fitted with the Temkin equation. The adsorption kinetics can be well described by the pseudo-second-order kinetics model. The values of ΔG, ΔH and ΔS indicated that the adsorption of RB onto QCS/PS-G8-2-8 was spontaneous and exothermic.