树脂填充聚醚砜纤维吸附剂对牛血清蛋白吸附性能的研究

重点研究树脂填充聚醚砜(PES)纤维吸附剂与模型蛋白质牛血清蛋白(BSA)之间的吸附与脱附行为.结果表明,蛋白质BSA在树脂填充PES纤维吸附剂中的平衡吸附过程较好地符合朗格缪尔吸附模型,树脂Lewatit CNP80ws填充PES吸附剂的最大吸附容量约为139mg BSA/g吸附剂.表面具有开孔结构的树脂填充PES纤维吸附剂的吸附速率较快,在不同结构纤维吸附剂中BSA的扩散系数在1·82×10-14~8·7×10-14m2/s范围内变化.另外,考察了BSA溶液的pH与洗脱剂等因素对吸附剂吸附与脱附性能的影响,研究结果对蛋白质的实际分离纯化具有重要的参考价值.     

An Analysis of the Interactions of BSA with an Anion-Exchange Surface Under Linear and Non-Linear Conditions

The interactions of BSA with an anion-exchange adsorbent have been studied to aid in the understanding of protein adsorption in ion-exchange chromatography. Linear chromatography, flow microcalorimetry and isotherm measurements were used to analyze adsorption energetics in the linear and overloaded regions of the equilibrium isotherm. The effects of salt type, salt and protein concentration, and temperature are reported. It was observed that under all conditions studied the adsorption process was entropically driven. This was contrary to expectations, since at the pH selected ion exchange is expected to dominate. A major driving force for the adsorption of BSA on the anion exchanger was concluded to be the increase in entropy from the release of water due to interactions between hydrophobic regions on the protein and adsorbent. The data further suggest that the conformational entropy change accompanying protein adsorption on the ion exchanger may also be significant.     

Glutaraldehyde cross-linked epoxyaminated chitosan as an adsorbent for the removal and recovery of copper(II) from aqueous media

A novel glutaraldehyde cross-linked epoxyaminated chitosan (GA-C-ENCS) prepared through chemical modification was used as an adsorbent for the removal and recovery of Cu(II) from aqueous media. The adsorbent was characterized by FTIR, SEM-EDS, ESR, TG/DTG, BET-surface area and potentiometric titration. The Cu(II) adsorption process, which was pH dependent showed maximum removal at pH 6.0. Adsorption equilibrium was achieved within 3 h. The adsorption of Cu(II) followed a reversible-first-order kinetics. The equilibrium data were evaluated using the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The best interpretation for the equilibrium data was given by the Dubinin–Radushkevich isotherm. The adsorption capacity of the adsorbent increased from 3.11 to 3.71 mmol g⁻¹ when the temperature was increased from 20 to 50 °C. The complete removal of 20.7 mg L⁻¹ Cu(II) from electroplating industry wastewater was achieved by 0.4 g L⁻¹ GA-C-ENCS. Regeneration experiments were tried for four cycles and the results indicate a capacity loss of <7.0%.     

Adsorption of Zn2+ from Synthetic Wastewater Using Dried Watermelon Rind (D-WMR): An Overview of Nonlinear and Linear Regression and Error Analysis

Sustainable wastewater treatment is one of the biggest issues of the 21st century. Metals such as Zn²⁺ have been released into the environment due to rapid industrial development. In this study, dried watermelon rind (D-WMR) is used as a low-cost adsorption material to assess natural adsorbents’ ability to remove Zn²⁺ from synthetic wastewater. D-WMR was characterized using scanning electron microscope (SEM) and X-ray fluorescence (XRF). According to the results of the analysis, the D-WMR has two colours, white and black, and a significant concentration of mesoporous silica (83.70%). Moreover, after three hours of contact time in a synthetic solution with 400 mg/L Zn²⁺ concentration at pH 8 and 30 to 40 °C, the highest adsorption capacity of Zn²⁺ onto 1.5 g D-WMR adsorbent dose with 150 μm particle size was 25 mg/g. The experimental equilibrium data of Zn²⁺ onto D-WMR was utilized to compare nonlinear and linear isotherm and kinetics models for parameter determination. The best models for fitting equilibrium data were nonlinear Langmuir and pseudo-second models with lower error functions. Consequently, the potential use of D-WMR as a natural adsorbent for Zn²⁺ removal was highlighted, and error analysis indicated that nonlinear models best explain the adsorption data.     

Adsorption behaviour of microamounts of cesium on manganese dioxide

The adsorption of cesium on manganese dioxide from aqueous solutions has been studied in relation to pertinent variables such as shaking time, pH, composition of aqueous solutions, mass of adsorbent (10 mg–1 g) and concentration of adsorbate (10^–6–5·10^–3 M), using a radiotracer technique. The influence of various anions and cations on cesium adsorption was examined. The distribution coefficient of a variety of other elements was determined under similar conditions. The adsorption of cesium obeys a Freundlich-type isotherm over the entire concentration range investigated, whereas the Langmuir-type isotherm is followed only at moderate concentrations.     

Beta-Cyclodextrin-Decorated Magnetic Activated Carbon as a Sorbent for Extraction and Enrichment of Steroid Hormones (Estrone, β-Estradiol,Hydrocortisone and Progesterone) for Liquid Chromatographic Analysis

A β-cyclodextrin-decorated magnetic activated carbon adsorbent was prepared and characterized using various analytical techniques (X-ray diffraction (XRD), scanning electron microscopy–electron diffraction spectroscopy (SEM-EDS) and transmission electron microscopy (TEM)), and the adsorbent was used in the development of a magnetic solid-phase microextraction (MSPE) method for the preconcentration of estrone, β-estradiol, hydrocortisone and progesterone in wastewater and river water samples. This method was optimized using the central composite design in order to determine the experimental parameters affecting the extraction procedure. The quantification of hormones was achieved using high-performance liquid chromatography equipped with a photodiode array detector (HPLC-DAD). Under optimum conditions, the linearity ranged from 0.04 to 300 µg L⁻¹ with a correlation of determinations of 0.9969–0.9991. The limits of detection and quantification were between 0.01–0.03 and 0.033–0.1 µg L⁻¹, with intraday and interday precisions at 1.1–3.4 and 3.2–4.2. The equilibrium data were best described by the Langmuir isotherm model, and high adsorption capacities (217–294 mg g⁻¹) were obtained. The developed procedure demonstrated high potential as an effective technique for use in wastewater samples without significant interferences, and the adsorbent could be reused up to eight times.     

Biosorption of americium-241 by Saccharomyces cerevisiae

The biosorption of radionuclide ²⁴¹Am from solution by Saccharomyces cerevisiae (S. cerevisiae), and the effects of experimental conditions on the adsorption were investigated. The preliminary results showed thatS. cerevisiae is a very efficient biosorbent. An average of more than 99% of the total ²⁴¹Am could be removed by S. cerevisiae of 2.1 g/l (dry weight) from ²⁴¹Am solutions of 17.54–4386.0 mg/l (2.22 MBq/l–555 MBq/l) with adsorption capacities of 7.45–1880.0 mg/g biomass (dry weight) (0.94 MBq/g–237.9 MBq/g). The adsorption equilibrium was achieved within 1 hour and the optimum pH ranged 1–3. No significant differences on ²⁴¹Am adsorption were observed at 10–45 °C, or in solutions containing Au³⁺ or Ag⁺, even 2000 times above ²⁴¹Am concentration. The relationship between concentrations and adsorption capacities of ²⁴¹Am indicated the biosorption process should be described by the Freundlich adsorption isotherm.     

Biosorption of nickel from aqueous solutions by Acacia leucocephala bark: Kinetics and equilibrium studies

The biosorption of nickel(II) ions from aqueous solution by Acacia leucocephala bark was studied in a batch adsorption system as a function of pH, initial metal ion concentration, adsorbent dosage, contact time and temperature. The maximum Ni(II) adsorption was obtained at pH 5. Further, the biosorbents were characterized by Fourier Transformer Infrared Spectroscopy (FTIR). The experimental data were analysed using three sorption kinetic models viz., the pseudo-first- and second-order equations and the intraparticle diffusion model. Results show that the pseudo-second-order equation provides the best correlation for the biosorption process. The equilibrium nature of Ni(II) adsorption at different temperatures of 30, 40 and 50 °C have been described by the Langmuir and Freundlich isotherm models. The equilibrium data fit well Langmuir isotherm. The monolayer adsorption capacity of A. leucocephala bark as obtained from Langmuir isotherm at 30 °C was found to be 294.1 mg/g. The Chi-square (χ²) and Sum of the square errors (SSE) tests were also carried out to find the best fit adsorption isotherm and kinetic model. Isotherms have been used to determine thermodynamic parameters of the process, viz., free energy change (ΔG°), enthalpy change (ΔH°), and entropy change (ΔS°) were calculated indicating that this system was a spontaneous and endothermic process. Present investigation emphasized that A. leucocephala bark may be utilized as a low cost adsorbent for nickel removal.     

Fabrication and optimization calix[8]arene-PbS nanoadsorbents for the adsorption of methylene blue: Isotherms,kinetics and thermodynamics studies

The present study aims to determine the adsorption behaviour of methylene blue (MB) dye based on calix[8]arene-modified lead sulphide (PbS) nanoadsorbents under optimal conditions. Response surface methodology (RSM) was executed to evaluate the interactive effect of three factors (adsorbent dosage, contact time, and pH) on the adsorption of MB dye using a central composite design (CCD). The optimised values for adsorbent dosage, contact time, and pH solution were found to be 45.00 mg of calix[8]arene-modified PbS, contact time of 180 min, and pH 6. This study reports the results of batch adsorption experiments, which include the adsorption capacity, kinetics, and isotherm of the MB adsorption process. Pseudo-first order and pseudo-second order were demonstrated for their quality to fit the data. Pseudo-second order was the best in fitting the adsorption data with the higher R² values (R² > 0.928), indicating chemisorption to be the mechanism of adsorption. The Langmuir and Freundlich equilibrium models were employed to determine the isotherm parameters. The equilibrium assessment illustrated that the Langmuir isotherm model fitted well with the adsorption data, and a maximum MB adsorption capacity of 11.90 mg/g was achieved. The characterisation studies with EDX, FESEM, and FTIR indicated a successful synthesis of calix[8]arene-modified PbS.     

Protein Attachment Mechanism for Improved Functionalization of Affinity Monolith Chromatography (AMC)

This work aims at understanding the attachment mechanisms and stability of proteins on a chromatography medium to develop more efficient functionalization methodologies, which can be exploited in affinity chromatography. In particular, the study was focused on the understanding of the attachment mechanisms of bovine serum albumin (BSA), used as a ligand model, and protein G on novel amine-modified alumina monoliths as a stationary phase. Protein G was used to develop a column for antibody purification. The results showed that, at lower protein concentrations (i.e., 0.5 to 1.0 mg·mL⁻¹), protein attachment follows a 1st-order kinetics compatible with the presence of covalent binding between the monolith and the protein. At higher protein concentrations (i.e., up to 10 mg·mL⁻¹), the data preferably fit a 2nd-order kinetics. Such a change reflects a different mechanism in the protein attachment which, at higher concentrations, seems to be governed by physical adsorption resulting in a multilayered protein formation, due to the presence of ligand aggregates. The threshold condition for the prevalence of physical adsorption of BSA was found at a concentration higher than 1.0 mg·mL⁻¹. Based on this result, protein concentrations of 0.7 and 1.0 mg·mL⁻¹ were used for the functionalization of monoliths with protein G, allowing a maximum attachment of 1.43 mg of protein G/g of monolith. This column was then used for IgG binding–elution experiments, which resulted in an antibody attachment of 73.5% and, subsequently, elution of 86%, in acidic conditions. This proved the potential of the amine-functionalized monoliths for application in affinity chromatography.     

Single-Step Hydrothermal Synthesis of Biochar from H3PO4-Activated Lettuce Waste for Efficient Adsorption of Cd(II) in Aqueous Solution

Developing an ideal and cheap adsorbent for adsorbing heavy metals from aqueous solution has been urgently need. In this study, a novel, effective and low-cost method was developed to prepare the biochar from lettuce waste with H₃PO₄ as an acidic activation agent at a low-temperature (circa 200 °C) hydrothermal carbonization process. A batch adsorption experiment demonstrated that the biochar reaches the adsorption equilibrium within 30 min, and the optimal adsorption capacity of Cd(II) is 195.8 mg∙g⁻¹ at solution pH 6.0, which is significantly improved from circa 20.5 mg∙g⁻¹ of the original biochar without activator. The fitting results of the prepared biochar adsorption data conform to the pseudo-second-order kinetic model (PSO) and the Sips isotherm model, and the Cd(II) adsorption is a spontaneous and exothermic process. The hypothetical adsorption mechanism is mainly composed of ion exchange, electrostatic attraction, and surface complexation. This work offers a novel and low-temperature strategy to produce cheap and promising carbon-based adsorbents from organic vegetation wastes for removing heavy metals in aquatic environment efficiently.     

Expanded Bed Chromatography as a Tool for Nanoparticulate Separation: Kinetic Study and Adsorption of Protein Nanoparticles

Expanded bed adsorption was investigated together with its suitability for the practical recovery of nanoparticulate mimics of products such as plasmid DNA and viruses as putative gene therapy vectors. The study assessed the binding of protein nanoparticles fabricated from bovine serum albumin (BSA) with average size of 80 nm as a model system and viral size/charge mimic to the streamline DEAE adsorbent in the expanded bed column chromatography. The adsorption kinetics and adsorption mechanism for the BSA nanoparticles on the adsorbent were studied. In batch adsorption studies, the factors nanoparticle concentration, contact time and adsorbent amount, affecting adsorption isotherms were investigated. Subsequently the data were regressed against the Lagergren equation, which represents a first-order kinetics equation and also against a pseudo-second-order kinetics equation. The results demonstrated that the adsorption process followed a Langmuir isotherm equation. The kinetics of the adsorption process followed a pseudo-second-order kinetics model with a rate constant value of 0.025 g mg^?1 min^?1. The dynamic binding capacity of the BSA nanoparticles on an expanded bed was calculated. The recovery of the nanoparticles was more than 85%.     

Synthesis and characterization of antibacterial chromium iron oxide nanoparticle‐loaded activated carbon for ultrasound‐assisted wastewater treatment

The aim of this study was to evaluate the surface adsorption capacity of CrFeO₃ nanoparticle‐loaded activated carbon (CrFeO₃‐NPs–AC) for the removal of a cationic dye (methyl violet, MV). CrFeO₃‐NPs were hydrothermally synthesized and loaded on AC followed by characterization using X‐ray diffraction, field‐emission scanning electron microscopy and energy‐dispersive and Fourier transform infrared spectroscopies. The CrFeO₃‐NPs were tested for in vitro antibacterial activities against Gram‐positive (Staphylococcus aureus) and Gram‐negative (Pseudomonas aeruginosa) bacteria. Minimum inhibitory and minimum bactericidal concentrations of CrFeO₃‐NPs–AC were obtained to be 50 and 100 μg ml^?1, respectively, against S. aureus and 25 and 50 μg ml^?1 against P. aeruginosa. These results indicated the antibacterial properties of CrFeO₃‐NPs–AC. To investigate the adsorption process, several systematic experiments were designed by varying parameters such as adsorbent mass, pH, initial MV concentration and sonication time. The adsorption process was modelled and the optimal conditions were determined to be 0.013 g, 7.4, 15 mg l^?1 and 8 min for adsorbent mass, pH, MV concentration and sonication time, respectively. The real experimental data were found to be efficiently explained by response surface methodology and genetic algorithm model. Kinetic studies for MV adsorption showed rapid sorption dynamics described by a second‐order kinetic model, suggesting a chemisorption mechanism. Then, the experimental equilibrium data obtained at various concentrations of MV and adsorbent masses were fitted to conventional Langmuir, Freundlich, Temkin and Dubinin–Radushkevich isotherm models. Dye adsorption equilibrium data were fitted well to the Langmuir isotherm. From the Langmuir model, the maximum monolayer capacity was calculated to be 65.67 mg g^?1 at optimum adsorbent mass.     

Adsorption of Chromium (VI) on <Emphasis Type="Italic">Azadirachta Indica</Emphasis> (Neem) Leaf Powder

A novel adsorbent was developed from mature leaves of the Neem tree (Azadirachta Indica) for removing metal ions from water. The adsorbent, in the form of fine powder, was found to be very effective in removing chromium (VI) from aqueous solution. The adsorption was carried out in a batch process taking different concentrations of the metal ion in aqueous solution with variation in adsorbent amount, pH, agitation time and temperature. The suitability of the adsorbent was tested with Langmuir and Freundlich isotherms and with various equilibrium kinetic data. A small amount of the Neem Leaf Powder (NLP) (1.6 g dm^–3) could remove as much as 87% of Cr (VI) in 300 min from a solution of concentration 14.1 mg dm^–3 at 300 K. The optimum range of pH for the adsorption process was 4.5–7.5 and since the natural pH of the Cr (VI) solution was 5.5, no addition of acid or alkali was necessary for achieving maximum adsorption. The adsorption coefficients indicated a high potentiality for the NLP to be used as an adsorbent for removing Cr (VI) from water.     

Microcalorimetric study of adsorption of glycomacropeptide on anion-exchange chromatography adsorbent

The adsorption of glycomacropeptide (GMP) from cheese whey on an anion-exchange adsorbent was investigated using isothermal titration microcalorimetry to measure thermodynamic information regarding such processes. Isotherms data were measured at temperatures of 25 and 45 °C, pH 8.2 and various ionic strengths (0–0.08 mol L⁻¹ NaCl). The equilibrium data were fit using the Langmuir model and the process was observed to be reversible. Temperature was observed to positively affect the interaction of the protein and adsorbent. Microcalorimetric studies indicated endothermic adsorption enthalpy in all cases, except at 45 °C and 0.0 mol L⁻¹ NaCl. The adsorption process was observed to be entropically driven at all conditions studied. It was concluded that the increase in entropy, attributed to the release of hydration waters as well as bounded ions from the adsorbent and protein surface due to interactions of the protein and adsorbent, was a major driving force for the adsorption of GMP on the anion-exchange adsorbent. These results could allow for design of more effective ion-exchange separation processes for proteins.     

Antibiotic Removal from the Aquatic Environment with Activated Carbon Produced from Pumpkin Seeds

Antibiotics are among the most critical environmental pollutant drug groups. Adsorption is one of the methods used to eliminate these pollutants. In this study, activated carbon was produced from pumpkin seed shells and subsequently modified with KOH. The adsorbent obtained through this procedure was used to remove ciprofloxacin from aqueous systems. Fourier Transform-Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), elemental, X-ray Photoelectron Spectroscopy (XPS), Brunauer–Emmett–Teller (BET) and Zeta analyses were used to characterize the adsorbent. The surface area, in particular, was found to be a very remarkable value of 2730 m²/g. The conditions of the adsorption experiments were optimized based on interaction time, adsorbent amount, pH and temperature. Over 99% success was achieved in removal operations carried out under the most optimal conditions, with an absorption capacity of 884.9 mg·g⁻¹. In addition, the Langmuir isotherm was determined to be the most suitable model for the adsorption interaction.     

Optimum isotherm equation and thermodynamic interpretation for aqueous 1,1,2-trichloroethene adsorption isotherms on three adsorbents

Aqueous 1,1,2-trichloroethene (TCE) adsorption isotherms were obtained on Ambersorb^1® 563 and 572 adsorbents and Filtrasorb^2® 400 granular activated carbon (GAC). The data for Ambersorb 563 adsorbent covers TCE concentrations from 0.0009 to 600 mg/L. The data for each adsorbent was fit to 15 isotherm equations to determine an optimum equation.The best equation for the TCE adsorption isotherms is the Dubinin-Astakov (DA) isotherm. The DA isotherm coefficients were used to estimate the TCE micropore volume and the adsorption potential distribution. For each adsorbent, the TCE micropore volume is equivalent to the N₂ porosimetry micropore volume. The mean adsorption potential is 18.8, 13.0, and 8.9 kJ/mol, with coefficients of variation of 0.37, 0.53, and 0.67, for Ambersorb 563 and 572 adsorbents and Filtrasorb 400 GAC, respectively. Thus, Ambersorb 563 adsorbent has the most energetic and most homogeneous adsorption volume, while Filtrasorb 400 GAC has the least energetic and most heterogeneous adsorption volume. For these reasons, Ambersorb 563 adsorbent has the highest TCE capacity at low concentrations, whereas Filtrasorb 400 GAC has the highest TCE capacity at high concentrations. The performance of Ambersorb 572 adsorbent is generally intermediate to the other two adsorbents.     

Equilibrium and Kinetic Study of Anionic and Cationic Pollutants Remediation by Limestone–Chitosan–Alginate Nanocomposite from Aqueous Solution

In this work, low-cost and readily available limestone was converted into nanolimestone chitosan and mixed with alginate powder and precipitate to form a triple nanocomposite, namely limestone—chitosan–alginate (NLS/Cs/Alg.), which was used as an adsorbent for the removal of brilliant green (BG) and Congo red (CR) dyes in aqueous solutions. The adsorption studies were conducted under varying parameters, including contact time, temperature, concentration, and pH. The NLS/Cs/Alg. was characterized by SEM, FTIR, BET, and TEM techniques. The SEM images revealed that the NLS/Cs/Alg. surface structure had interconnected pores, which could easily trap the pollutants. The BET analysis established the surface area to be 20.45 m²/g. The recorded maximum experimental adsorption capacities were 2250 and 2020 mg/g for CR and BG, respectively. The adsorption processes had a good fit to the kinetic pseudo second order, which suggests that the removal mechanism was controlled by physical adsorption. The CR and BG equilibrium data had a good fit for the Freundlich isotherm, suggesting that adsorption processes occurred on the heterogeneous surface with a multilayer formation on the NLS/Cs/Alg. at equilibrium. The enthalpy change (ΔH⁰) was 37.7 KJ mol⁻¹ for CR and 8.71 KJ mol⁻¹ for BG, while the entropy change (ΔS⁰) was 89.1 J K⁻¹ mol⁻¹ for CR and 79.1 J K⁻¹ mol⁻¹ BG, indicating that the adsorption process was endothermic and spontaneous in nature.     

Differential heats of adsorption of water vapors on the lithium form of clinoptilolite

The maximum possible lithium form of clinoptilolite (K1) with an ion-exchange capacity of 2.3 mEq/g, corresponding to 85% Kl in nature, was prepared. The isotherm of adsorption of water vapors on LiKl at 25°C in the region of maximally low equilibrium pressures (10^–10 torr) was calculated by the adsorption-isostere method and permits determining the complete thermodynamic functions of the system. The adsorption isotherm is completely described by the two-term equation from the theory of volume filling of micropores (TVFM). The wavy-stepwise shape of the curve of the heat of adsorption permitted establishing the stoichiometric correlation between the adsorption values and concentration of Li⁺ in LiKl. The energy of the Li⁺-OH₂ adsorption complex is 97 kJ/mole for a zero degree of filling. The integral average molar entropy of adsorption is 20 J/(mole·K) less than the entropy of a normal liquid. The state of the H₂O molecules in LiKl is ice-like.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 10, pp. 2186–2188, October, 1989.     

Strongly Basic Anion Exchange Resin Based on a Cross-Linked Polyacrylate for Simultaneous C.I. Acid Green 16, Zn(II), Cu(II), Ni(II) and Phenol Removal

The adsorption ability of Lewatit S5528 (S5528) resin for C.I. Acid Green 16 (AG16), heavy metals (Zn(II), Cu(II) and Ni(II)) and phenol removal from single-component aqueous solutions is presented in this study to assess its suitability for wastewater treatment. Kinetic and equilibrium studies were carried out in order to determine adsorption capacities, taking into account phase contact time, adsorbates’ initial concentration, and auxiliary presence (NaCl, Na₂SO₄, anionic (SDS) and non-ionic (Triton X100) surfactants). The pseudo-second-order kinetic model described experimental data better than pseudo-first-order or intraparticle diffusion models. The adsorption of AG16 (538 mg/g), phenol (14.5 mg/g) and Cu(II) (5.8 mg/g) followed the Langmuir isotherm equation, while the uptake of Zn(II) (0.179 mg^1−1/nL^1/n/g) and Ni(II) (0.048 mg^1−1/nL^1/n/g) was better described by the Freundlich model. The auxiliary’s presence significantly reduced AG16 removal efficiency, whereas in the case of heavy metals the changes were negligible. The column studies proved the good adsorption ability of Lewatit S5528 towards AG16 and Zn(II). The desorption was the most effective for AG16 (>90% of dye was eluted using 1 mol/L HCl + 50% v/v MeOH and 1 mol/L NaCl + 50% v/v MeOH solutions).