Adsorption Elution Research Articles

Adsorption of Copper (Ii) Ion by Leucaena Leucocephala Pods

In this work, the efficiency of Leucaena leucocephala pods, an agricultural waste, to remove copper (Cu) ions in aqueous solution by adsorption. Batch mode experiments were carried out at 30 ◦C to study the influence of pH, contact time (t) and dosage on the adsorption of Cu by Leucaena leucocephala pods. The surface behaviour and the composition of the Leucaena leucocephala pods was characterized using pH of point of zero charge (pHPZC), Fourier transform infrared spectroscopy (FTIR). It is shown that Leucaena leucocephala pods adsorbent can effectively remove Cu from aqueous solutions. The best sorption results were obtained at pH 8.0 , 0.75 g dosage and within time 80 min. The FTIR studies indicated was existence of surface hydroxyl, carboxyl and carbonyl groups. Adsorption method was used to successfully execute post adsorption elution of the loaded metal.

Improving cesium removal to clean-up the contaminated water using modified conjugate material

Crown ether based conjugate material was enabling the high functionality for stable complexation mechanism with cesium (Cs) and attracted the scientific community for potential real radioactive contaminated water treatment. This study was focused on ligand anchored conjugate material for radioactive Cs disposal based on adsorption techniques from nuclear liquid waste in Fukushima with high selectivity. A macrocyclic ligand of acetyl dibenzo-20-crown-6-ethers (AcDB20C6) was synthesized and directly embedded onto mesoporous inorganic silica. The Cs adsorption behavior was carried out with batch equilibrium techniques. The affecting experimental parameters such as solution pH, contact time, initial Cs concentration and competitive adsorption of Na and K ion concentrations were measured and optimized systematically. The sensitive pH range for high Cs removal was with broad range of 5.5–9.0, and the maximum adsorption capacity was 65.06 mg/g by the material at pH 7.0. The results clarified that conjugate material was high selectivity towards Cs even in the presence of a high level of Na and K ions rather than inorganic adsorbent because of the possible Cs-π interaction of the benzene ring from the crown ether ligand. The material was successfully investigated for radioactive Cs disposal for the potential treatment in Fukushima in the connection of in nuclear contaminated water treatment. The adsorbed Cs was desorbed with the eluent of 0.20 M HCl and then simultaneously regenerated at the same into the initial form for the next disposal operation after washing with water. The conjugate material was kept high functionality even in several cycles during adsorption–elution–regeneration processes. Then the proposed material could be used as promising material for selective radioactive Cs disposal from contaminated water in Fukushima, Japan.

Removal of Pb (II) from aqueous solution using nanoadsorbent of Oryza sativa husk: Isotherm, kinetic and thermodynamic studies

This research focus on the removal of Pb (II) ions from aqueous solution by adsorption process using nanoadsorbent developed from agricultural waste Oryza sativa husk (OSH). Surface morphology of nanoadsorbent was analyzed by FE-SEM, elemental composition by EDX and size by AFM. Attachment of functional groups on nanoadsorbent was determined by FTIR. The effect of pH, dose, contact time, initial concentration and temperature were investigated. Optimum adsorption of lead at pH 8, contact time 70 min at 60 °C temperature with 0.6 g/50 mL nanoadsorbent dose obeyed pseudo second order kinetic model with R2 0.996. Pb (II) adsorption was analyzed by Freundlich, Langmuir and Temkin models. Freundlich isotherm model with correlation coefficient R2 0.999 was best fitted. Thermodynamic parameters anticipated the adsorption process to be endothermic and spontaneous. Post adsorption elution was carried out successfully. Results demonstrate that OSH is a low cost and eco-friendly choice for Pb (II) remediation.

Fast and highly selective separation of His-tagged proteins by Ni2+-carrying magnetic core–shell nanoparticles

In this study, core–shell Fe3O4@Au nanoparticles with good chemical stability and tunable particle size were synthesized via Au–S bonding, which overcomes the challenges encountered for the reported preparation of Fe3O4@Au. The surface of nanoparticles was investigated by TEM, XRD, XPS, FT-IR, VSM and DLS which characterized the size, morphology, chemical lattice, elemental analysis, functional groups, magnetic strength, and size distribution. The results showed that Fe3O4@Au/NTA-Ni2+ magnetic nanocomposites were spherical with an average diameter of 469.5 nm, and superparamagnetic with saturation magnetization of 7 emu/g. The magnetic nanocomposites were directly utilized for one-step purification of His-tagged proteins from Description Escherichia coli lysate. The as-separated proteins were qualitatively validated by gel analysis and quantitatively measured by UV–visible spectroscopy. The binding capacity of Fe3O4@Au/NTA-Ni2+ towards His-tagged proteins was 48.3 mg/g. The target proteins were separated with high purity and separation efficiency up to 96.6%. Their specificity and enrichment ability were maintained during six cycles of adsorption–elution operations. The advantages of this novel nanoparticle can open a window for the multifunction of nanomaterials and their biological application.

Modeling of the static batch desorption and dynamic column elution of geniposidic acid from a porous anion-exchanger

For several decades, plenty of iridoid glycosides including geniposide (GS) and geniposidic acid (GSA) in the gardenia yellow pigment extraction waste water was not recovered effectively. This study is aimed to supply an efficient GSA recycling route. In this study, a model incorporating a superficial desorption rate constant was applied to the batch GSA desorption process, i.e., recycling, for verification. Then, the model was further developed to research the feasibility in dynamic column elutions simulation through porous uniform media. The simulation approach was done by coupling velocity field and mass transfer equations using COMSOL Multiphysics™ Finite element method, with appropriate mesh refinement was employed to solve the equation system. The HCl solutions ranging from 0.03 mol/L to 0.06 mol/L were used to desorb/elute the GSA from a presaturated polymeric porous anionic resin D08. Good results were accomplished in terms of ion exchange desorption rate and GSA recovery. The pore diffusion model (PDM) considering counter ion was established to describe the desorption/elution kinetics in the batch/column experiment. By the least square fitting method, the superficial desorption rate constant Kd of GSA/HCl reaction on the ion-exchange sites of porous resin was fitted to 0.116 L/(mol s). Subsequently, this value was sequentially applied in the simulation of the dynamic elution process. The individual pore diffusion coefficients for GSA and Cl− were estimated to be 5.07 × 10−10 and 1.77 × 10−9 m2/s, respectively. In order to validate the simulation feasibility of this pore diffusion model to a dynamic column elution process, the effects of HCl concentration, flow rate and column's height/diameter ratio on the column performance were investigated systematically. The results from this work should serve as motivation for further experimental and theoretical study in the scaling-up of GSA purification process. Finally, repeated adsorption–elution column cycles were simulated by the PDM model well.

Recovery of Platinum and Palladium from Spent Automobile Catalyst by Solvent-Impregnated Resins

ABSTRACTSeparation of platinum and palladium, using solvent-impregnated resin (SIR) impregnating di-hexylamine (DHA), di-n-octylamine (DOA), or di-hexyl sulfide (DHS), coated by polyvinyl alcohol crosslinked by glutaraldehyde, was investigated. Coating of the SIR successfully suppressed leakage of the extractant during adsorption. The coated SIR was applied to chromatographic recovery of the two metals and quantitative adsorption–elution was performed via the frontal analysis mode. The adsorption of Pt and Pd was achieved, while adsorption of the co-existing metals in the leaching solution was suppressed. Separation of Pt and Pd was achieved by employing sequential chromatography system together with the quantitative elution of Pt from DHA-SIR with the mixture of 0.5 mol/L thiourea and 0.5 mol/L HCl and that of Pd from DHS-SIR with the mixture of 0.1 mol/L thiourea and 0.5 mol/L HCl solution. Finally, elementary Pt was then obtained from the eluent of sequential chromatography system by simultaneous precipitation and reduction of Pt with sodium borohydride with 99.2% purity.

Preparation of single-chain antibody against VP3 protein of duck hepatitis virus type 1 by phage display technology

To construct phage antibody library for VP3 protein of duck hepatitis virus type 1(DHAV-1) and pan the specific single-chain variable fragment antibody (scFv), total RNA was extracted from the protein VP3- immunized mice spleen., vp3 gene encoding VP3 protein was amplified from the genome of DHAV-1 by RT-PCR method for the following recombinant pET-VP3 construction, immunogenic VP3 expression and purification, and combined with SOE-PCR method to complete the assembly of scFv. The scFv gene was cloned into pCANTAB5E vector for phage antibody library construction. Finally, the library for anti-VP3 scFv was screened by four rounds of adsorption–elution–enrichment with the purified VP3 protein. The characters of binding ability, specificity and neutralization of soluble antibodies expressed were evaluated by ELISA. The results showed 7 VP3-specific scFvs have been screened and identified with high both sensitivity and specificity for binding DHAV-1. To our knowledge, this is the first report for VP3-specific scFv of DHAV-1 and potentially promising application used in prevention and treatment of duck viral hepatitis.

Facile Design of Green Engineered Cellulose/Metal Hybrid Macrogels for Efficient Trace Phosphate Removal

Cellulose/metal hybrid macrogels were prepared by immobilizing uniformly dispersed thiolate-modified Fe2O3 nanoparticles into a cellulose matrix. The structure and properties of the hybrid macrogels were characterized using SEM, EDS, water contact angle, XRD, FTIR, XPS, and adsorption tests. The hybrid macrogels exhibited good stability, convenient operation, and high selectivity for trace phosphate removal, with a remaining phosphorus concentration of only 0.15 mg L–1 in 200 min (5 mg L–1 initial concentration). The influences of pH, ionic strength, and competitive anions were also investigated. The hybrid macrogels could be recovered by simple and rapid magnetic separation and regenerated in NaOH solution. During 5 cycles of the adsorption–elution–regeneration stability test, the hybrid macrogels still retained 80% adsorption capacity of trace phosphate. In this work, utilization of natural polymer was combined with green and sustainable technology to develop economically sustainable, eco-friendly, and ...

Cellulose-based virus-retentive filters: a review.

Viral filtration is a critical step in the purification of biologics and in the monitoring of microbiological water quality. Viral filters are also essential protection elements against airborne viral particles. The present review first focuses on cellulose-based filter media currently used for size-exclusion and/or adsorptive filtration of viruses from biopharmaceutical and environmental water samples. Data from spiking studies quantifying the viral filtration performance of cellulosic filters are detailed, i.e., first, the virus reduction capacity of regenerated cellulose hollow fiber filters in the manufacturing process of blood products and, second, the efficiency of virus recovery/concentration from water samples by the viradel (virus adsorption–elution) method using charge modified, electropositive cellulosic filters or conventional electronegative cellulose ester microfilters. Viral analysis of field water samples by the viradel technique is also surveyed. This review then describes cellulose-based filter media used in individual protection equipment against airborne viral pathogens, presenting innovative filtration media with virucidal properties. Some pros and cons of cellulosic viral filters and perspectives for cellulose-based materials in viral filtration are underlined in the review.

Silica-based solvent impregnated adsorbents for separation of rare earth metals

ABSTRACTSilica-based solvent impregnated adsorbents are prepared, employing 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester as an extractant. Two kinds of silica particles are used as supports; (i) those whose surface is coated by a styrene/divinylbenzene copolymer and (ii) those whose hydroxyl-terminated pentadimethyl siloxane group is immobilized on the surface. The adsorbent based on silica particles coated by styrene/divinylbenzene can be repeatedly used for adsorption–elution processing, while the adsorption capacity of the adsorbent based on silica particles modified by the siloxane group is decreased by repeated cycles. The adsorbent is applicable to chromatographic operation for Dy/Nd, and quantitative adsorption–elution is achieved.

Adsorption of Lead on Cucumber Peel

The competency of cucumber peel (CP) was explored for adsorption of lead. Optimum adsorption occurred at pH 5.0 and at incubation temperature of 30 °C. The process of adsorption was quite fast to be completed within a time frame of 60 min obeying pseudo second order rate kinetics. 1.0 g sorbent was capable enough to adsorb 133.60 mg lead (qmax) with Langmuir isotherm model categorically illustrating the adsorption process. The magnitude of hindrance exerted by cadmium in binary system as a consequence of co-ion effect was found to be rather insignificant. Functional group modification study confirmed principal role of carboxyl group in metal binding. The biomass was characterized by different instrumental analyses like TGA, SEM, EDAX, XRD, FTIR and zeta potential measurement which additionally authenticated the sorption phenomenon. Post adsorption elution of the loaded metal was successfully executed using HCl as eluant.

Ligand field effect for Dysprosium(III) and Lutetium(III) adsorption and EXAFS coordination with novel composite nanomaterials

The separation of lanthanide (Ln(III)) elements from various waste materials is a significant issue facing developed countries. However, the chemical behaviour of Ln(III) are very similar and complex, and it is an important to understand clearly to optimize the separation processes under various conditions based on the ion-selective ligands and ligand field effect for specific Ln(III) separation with semi-cavity and high flexibility for competitiveness of industries and continuous economic growth. The study developed the hybrid Lewis base ligand functionalized alumina-silica based composite nanomaterials for heavier Ln(III) of Dy(III) and Ly(III) separation and recovery. The alumina-silica fabrication, intra-series separation, solution acidity, ion-selective and coordination mechanism by EXAFS were carried out systematically. The Dy(III) and Lu(III) adsorption was high in acidic region as the high pH area is avoided due to the hydroxyl precipitation. The adsorption data were fitted well with the Langmuir adsorption model for the both elements and the calculated maximum adsorption capacity was 125.44 and 129.77mg/g for Dy(III) and Lu(III) ions, respectively. The ion selectivity was also performed in the presence of divers ions and Dy(III) or Lu(IIII) ions was preferentially adsorbed in a competitive environment. In the coordination mechanism by EXAFS, the Dy(III) and Lu(III) ions were strongly coordinated with the O and N atoms of the hybrid Lewis base ligand in the composite nanomaterial. Moreover, adsorption–elution cyclic results demonstrated that Dy(III) and Lu(III) ions adsorbed composite nanomaterial could be effectively desorbed HNO3 acid, and the regenerated nanomaterial was able to repeated use without significant deterioration in its original performances. All these characteristics make the nanomaterial an ideal solid-phase materials for effective Dy(III) and Lu(III) ions adsorption in complicated matrix samples.

A handy chart for the interpretation of sequential differential adsorption-elution procedure.

A handy chart for the interpretation of sequential differential adsorption-elution procedure.

Evaluation of the effectiveness of carbonaceous adsorbents on simultaneous extraction of heavy metals: a comparative study

A solid-phase extraction procedure was described for the quantitative extraction of a mixture of lead, cadmium, copper and bismuth ions on modified multiwalled carbon nanotubes, graphene oxide nanosheets, activated carbon and carbon black, individually. Then, the adsorbed analytes were eluted with HCl and introduced directly to electrothermal atomic absorption spectrometry. The surface morphology of the adsorbents was investigated by field-emission scanning electron microscopy. The parameters affecting the adsorption–elution process such as pH and flow rate of the sample solution—type, concentration, volume and flow rate of eluent were optimized in detail. Adsorption capacities, breakthrough volumes and enrichment factors were also studied. Wide calibration curves with good correlation coefficients, low detection limits and acceptable relative standard deviations were obtained for all analytes on different adsorbents. The results showed, when nanoadsorbents were used, higher adsorption and recoveries were obtained for all of the studied metal ions. The proposed method has been applied to the determination of Pb(II), Cd(II), Cu(II) and Bi(III) in water, wastewaters, human urine and human hair samples. The spiked recoveries were in the range 93.0–106%. Also, the accuracy of the method was validated by analyzing a certified reference material.

How do we approach dilemmas in red cell testing?

Despite the large number of serologically identified red cell antigens to date, it is reassuring to note that in the common clinical scenario, the transfusion laboratory would only likely deal with a narrow range of clinically significant antibodies to specific antigens of blood group systems. Accurate ABO and RhD typing still remains the most crucial step in pretransfusion testing followed by the antibody screen. The correct identification of single antibodies or multiple antibodies and whether they are alloantibodies or autoantibodies is necessary so that corresponding antigen‐negative red cells can be supplied. Clinically insignificant antibodies or what some would denote as ‘nuisance’ antibodies would need to be differentiated from clinically significant antibodies.When discrepancies occur between forward and reverse ABO typing, it is crucial that laboratories resolve the discrepancy before a specific ABO blood group is assigned. The inclusion of O cells in reverse grouping, anti‐H and anti‐A1 lectins in the forward, performing the typing on a range of temperatures using washed red cells and careful interpretation of agglutination patterns, would usually provide an answer. On occasions, a saliva test may be necessary and rarely molecular typing. With regard to RhD typing, test systems should identify RhD‐negative and D‐variant individuals so that D‐negative units can be issued to them. Testing with antisera from different clones, the use of adsorption–elution techniques and RhD.CcEe typing aids in coming to a conclusion, before molecular testing becomes necessary. Extended red cell phenotyping is indicated if the patient is at risk for developing a red cell antibody.

Solid phase sensitive palladium(II) ions detection and recovery using ligand based efficient conjugate nanomaterials

In this work, ligand based colorimetric conjugate nanomaterials was designed for highly selective and sensitive detection and removal of palladium (Pd(II)) ions. The proposed nanomaterials was exhibited the relatively rapid response and high selectivity toward Pd(II) ions without using additional reagents. Upon the addition of Pd(II) ions solution to the conjugate nanomaterials, the nanomaterials gave an absorption spectral intensity at around 425nm and displayed a selective chromogenic behavior toward Pd(II) ions from colorless to light brown, which could be easily observed by the naked eye without using high-tech instruments. In addition, the solid-state nanomaterials showed great selectivity to Pd(II) ions at optimum conditions compared with diverse common ions as verified using UV–Vis–NIR analysis. Then the limit of detection by the nanomaterials was calculated to be 1.17μg/L for Pd(II) ions. The pH of aqueous mediums was optimized through batch adsorption studies. The experimental data showed an interesting affinity between nanomaterials and Pd(II) ions at pH 2.0. The Pd(II) adsorption kinetic was fast, and the equilibrium data were represented well by the Langmuir adsorption isotherm equation with a monolayer adsorption capacity of 157.23mg/g. Moreover, the conjugate nanomaterials was able to adsorbed the Pd(II) ions even in the presence of a high amount of foreign competing cations. More than 99% of Pd(II) ions was eluted in single contact using 0.10M HCl–0.20 M thiourea and nanomaterials were reused several cycles of adsorption–elution–regeneration. Then the proposed solid design conjugate nanomaterials could be used as efficient and cost-effective material for selective Pd(II) ions detection and removal at optimum conditions.

Molecular mechanisms underlying DEL phenotype among ethnic Han individuals from Jiangsu

To explore the molecular mechanism underlying the DEL phenotype among RhD negative ethnic Han individuals from Jiangsu, China. The DEL phenotype was determined by an adsorption elution test among 57 RhD negative blood donors. The Rh C, c, E, and e phenotypes were detected by a tube method. PCR with sequence-specific primering (PCR-SSP) assay was used to determine the RHCE genotypes. The RHD gene of the DEL individuals were amplified with polymerase chain reaction and subjected to Sanger sequencing analysis. Among the 57 RhD negative donors, 10 (17.54%) were determined as having the DEL phenotype. The major RhCE phenotypes for DEL and RhD negative cases were RhCcee (80.0%) and Rhccee (61.7%), respectively. All RHD gene sequences of the 10 individuals have harbored a G>A mutation at position 1227 of exon 9. A proportion of RhD negative individuals determined by routine serological method are actually DEL with RHD gene mutations. RHD *1227A is the most prevalent DEL genotype among ethnic Han Chinese from Jiangsu. Further research on the phenotype and underlying molecular mechanism of DEL is important for blood transfusion.

Encapsulation of cesium from contaminated water with highly selective facial organic–inorganic mesoporous hybrid adsorbent

The present work was developed an efficient mesoporous hybrid adsorbent (MHA) for selective cesium (Cs) removal from contaminated water. A novel macrocyclic ligand of di-o-benzo-p-xylyl-28-crown-8-ether (DOBPX28C8) was prepared and successfully anchored onto the mesoporous silica for the fabrication of MHA using direct immobilization approach and serving as an efficient adsorbent for Cs removal. The Cs adsorption onto the MHA was evaluated under the different experimental conditions, including initial pH solution, contact times, initial Cs concentrations, presence of high amount of potassium (K) and sodium (Na). The applicable pH range for high Cs removal was evaluated at 5.50. The Cs adsorption data were well fitted to the Langmuir adsorption model and was a monolayer adsorption with the maximum adsorption capacity of 97.63mg/g. In the presence of a high amount of K (7.69mM), the Cs adsorption was slightly affected because the hydration radius of K (3.3Å) is close to the Cs (3.25Å) than that of the other cation of Na (3.6Å). Also the Cs adsorption efficiency was more than 75% and 89% even in the presence of 1025-fold K and 1739-fold Na, respectively. The functional group of DOBPX28C8 ligand embedded onto the mesoporous silica exhibited more conformational freedom, and the benzene ring in para position was consolidated for π-electron orientation with expanding the ring size of DOBPX28C8 for easy capturing with high selectivity and adsorption ability towards the Cs. The regeneration study indicated that the adsorption process was relatively stable even after six consecutive adsorption–elution cycles. The fastest mass transports, high selectivity, adsorption capacity and reusability are to make promising of the MHA in the contaminated water remediation in Fukushima, Japan.

Prevalence of weak D phenotype among D negative C/E+ blood donors in Morocco

Aims: Determination of D variants is important for selection of blood products and to prevent anti-D-related hemolytic disease of the fetus and newborn. The prevalence of weak D phenotypes varies significantly among different ethnic populations. In Morocco, D variants have not been fully characterized. The purpose of this study was to determine prevalence of weak D among D negative and C/E+ blood donors and distribution of Rhesus blood group antigens using serologic methods. Methods: A total of 15,865 blood samples from Moroccan blood donors were tested for D, C, c, E, e antigens by routine serologic methods. Among blood donors serologically D negative C+ and/or E+, 63 samples were tested for weak D by indirect antiglobuline test, enzymatic treated cells test and adsorption elution technique. Results: Among 63 samples tested, 10 were positive by serologic methods (15.87%). Six samples identified as weak D by enzymatic test and four samples identified as Del by adsorption elution. Rhesus blood group antigens are distributed as DCcee: 38.85% and dccee :8.77%. Conclusion: The prevalence of D variants must be considered in transfusional and obstetrical strategy for RhD typing to ensure blood transfusion safety by optimizing the management of D-negative RBC units and Rh immune globulins.

Efficient purification of lysozyme from egg white by 2-mercapto-5-benzimidazolesulfonic acid modified Fe3O4/Au nanoparticles

2-Mercapto-5-benzimidazolesulfonic acid (MBISA) modified Fe3O4/Au nanoparticles were synthesized in aqueous solution and characterized by photo correlation spectroscopy (PCS) and vibrating sample magnetometer (VSM). The so-obtained Fe3O4/Au-MBISA nanoparticles were capable of specific adsorbing lysozyme. The maximum amount of lysozyme adsorbed on 1.0mg Fe3O4/Au-MBISA nanoparticles was 346μg. The lysozyme desorption behavior was studied and the lysozyme recovery from Fe3O4/Au-MBISA nanoparticles approached 100% under optimal conditions, and the reusability studies showed that the nanoparticles could maintain about 91% of the initial lysozyme adsorption capacity after 7 repeated adsorption–elution cycles. The Fe3O4/Au-MBISA nanoparticles were used in the purification of lysozyme from chicken egg white, which was verified by a single SDS-PAGE band. Therefore, the obtained Fe3O4/Au-MBISA nanoparticles exhibited excellent performance in the direct purification of lysozyme from egg white.