柱芳烃基多孔聚合物的制备及其吸附性能

将柱[5]芳烃与1,3,5-三乙炔苯(TEB)通过Sonogashira偶联反应制备了一类新型多孔有机聚合物P[5]-TEB,进而通过脱甲基反应对其进行改性得到多羟基的多孔聚合物P[5]OH-TEB,对二者的物理化学性质和吸附性能进行研究。 氮吸附测试表明,羟基的引入使P[5]OH-TEB的比表面积变大,同时引入微孔结构。 染料吸附实验表明,两聚合物对亚甲基蓝吸附过程符合Langmuir模型,P[5]OH-TEB对亚甲基蓝有更大的吸附量;吸附动力学试验表明,吸附过程更符合拟二级动力学模型,属于化学吸附过程,改性之后P[5]OH-TEB有更快的吸附速率;选择性吸附实验表明,羟基引入聚合物后聚合物对阳离子染料的吸附性能提升,对阴离子染料的吸附效果变差。     

Synthesis and performance evaluation of chitosan/zinc oxide nanocomposite as a highly efficient adsorbent in the removal of reactive red 198 from water

In this study, Chitosan and Chitosan-zinc oxide (ZnO) nanocomposite were prepared and applied as a low-cost adsorbent with high adsorption capacity for removing reactive red 198 (RR 198) dye from contaminated water. After preparation, it was characterized using FT-IR, XRD, and SEM. The effect of pH, temperature, time, adsorbent amount, and initial dye concentration were investigated in the removal efficiency of RR 198. The maximum adsorption capacity (q_m) obtained from the Langmuir equation was 172.41 mg/g in adsorbent dose of 0.1 g/L, pH: 4, temperature of 25°C, adsorption time of 40 min. The thermodynamic parameters demonstrated the spontaneous and endothermic nature of the adsorption process. Due to the high efficiency of chitosan/ZnO nanocomposite in removal of RR 198 from water and advantages such as high adsorption capacity, simple synthesis, and easy application, it can be used as an effective method in the removal of RR 198 from water.     

Mechanisms and kinetics of trisodium 2-hydroxy-1,1'-azonaphthalene-3,4',6-trisulfonate adsorption onto chitosan

Chitosan, a naturally abundant biopolymer, has widely been studied for metal adsorption from various solutions, but the extension of chitosan as an adsorbent to remove organic substances from water and wastewater has seldom been explored. In this study, the adsorption of an azo dye, trisodium 2-hydroxy-1,1'-azonaphthalene-3,4',6-trisulfonate (1), from aqueous solution onto the various degrees of deacetylated chitosan has been investigated. Equilibrium studies have been carried out to determine the capacity of chitosan for dye. The experimental data were analyzed using two isotherm correlations, namely, Langmuir and Freundlich equations. The linear correlation coefficients were determined for each isotherm and the Langmuir provided the best fit. The experimental adsorption isotherms were perfectly reproduced in the simulated data obtained from numerical analysis on the basis of the Langmuir model and the isotherm constants. Adsorption of (1) onto the chitosan flakes was found to be strongly depending on degrees of deacetylation in chitosan and temperatures. Significant amounts of (1) were adsorbed by chitosan 8B (higher degree of deacetylated chitosan), but the adsorption capacity was reduced remarkably with increasing solution temperatures. Thermodynamic parameters such as change in free energy (DeltaG), enthalpy (DeltaH), and entropy (DeltaS) were also determined. In addition, kinetic study indicated that the adsorption process mechanisms were both transport- and attachment-limited.     

Adsorption mechanism of synthetic reactive dye wastewater by chitosan

Chitosan was able to remove the color from synthetic reactive dye wastewater (SRDW) under acidic and caustic conditions. The effect of the initial pH on SRDW indicated that electrostatic interaction occurred between the effective functional groups (amino groups) and the dye under acidic conditions. Moreover, SRDW adsorption under caustic conditions was also affected by the covalent bonding of dye and hydroxyl groups of chitosan. In addition, elution tests confirmed that chemical adsorption occurred under acidic conditions, while both physical and chemical adsorption appeared under caustic conditions. The spectra of attenuated total reflectance Fourier transform infrared spectrometry confirmed the functional groups of chitosan that affected the SRDW adsorption. However, the maximum adsorption capacities of chitosan increased when the temperature increased. The maximum adsorption capacity of chitosan obtained from the Langmuir model was 68, 110, and 156 mg g(-1) under a system pH of 11.0 at 20, 40, and 60 degrees C, respectively. The negative values of enthalpy change (DeltaH), free energy change (DeltaG), and entropy change (DeltaS) indicated an exothermic, spontaneous process and decreasing disorder of the system, respectively. Therefore, the mechanism of SRDW adsorption by chitosan was probably by chemical adsorption for a wide range of pH's and at high temperatures.     

壳聚糖亲和磁性毫微粒的制备及其对蛋白质的吸附性能研究

以壳聚糖为包裹材料包埋自制的磁流体 ,制备了具有核 壳结构的磁性毫微粒 ,并偶联色素配基CibacronBlue 3GA(偶联量 1 4 .5μmol/mL)得到了一种新型亲和磁性毫微粒 .结果表明 ,所得亲和磁性微球具有较窄的粒径分布、形状规整 .以牛血清白蛋白 (BSA)和溶菌酶 (Lys)为目标蛋白 ,考察了该亲和磁性毫微粒的吸附性能 ,发现其对BSA和Lys的吸附量分别为 4和 2 8mg/g,吸附行为满足Langmuir吸附等温式 ,且对时间依赖性小而对溶液离子强度敏感 .     

Removal of malachite green from dye wastewater using mesoporous carbon adsorbent

Mesoporous carbon was synthesized for the removal of a cationic dye malachite green (MG) from aqueous solution. The studies were carried out under various experimental conditions such as contact time, dye concentration, adsorption dose and pH to assess the potentiality of mesoporous carbon for the removal of malachite green dye from wastewater. The sorption equilibrium was reached within 30 min. In order to determine the adsorption capacity, the sorption data were analyzed using linear form of Langmuir and Freundlich equation. Langmuir equation showed higher conformity than Freundlich equation. More than 99% removal of MG was reached at the optimum pH value of 8.5. From kinetic experiments, it was concluded that the sorption process followed the pseudo-first-order kinetic model. This study showed that mesoporous carbon can be recommended as an excellent adsorbent at high pH values.     

Cellulose nanocrystals as promising adsorbents for the removal of cationic dyes

Cellulose nanocrystals (CNCs) prepared from cellulose fibre via sulfuric acid hydrolysis was used as an adsorbent for the removal of methylene blue (MB) from aqueous solution. The effects of pH, adsorbent dosage, temperature, ionic strength, initial dye concentration were studied to optimize the conditions for the maximum adsorption of dye. Adsorption equilibrium data was fitted to both Langmuir and Freundlich isotherm models, where the Langmuir model better described the adsorption process. The maximum adsorption capacity was 118 mg dye/g CNC at 25 °C and pH 9. Calculated thermodynamic parameters, such as free energy change (ΔG = ?20.8 kJ/mol), enthalpy change (ΔH = ?3.45 kJ/mol), and entropy change (ΔS = 0.58 kJ/mol K) indicates that MB adsorption on CNCs is a spontaneous exothermic process. Tunability of the adsorption capacity by surface modification of CNCs was shown by oxidizing the primary hydroxyl groups on the CNC surface with TEMPO reagent and the adsorption capacity was increased from 118 to 769 mg dye/g CNC.     

Interaction of indigo carmine dye with chitosan evaluated by adsorption and thermochemical data

Chitosan can use its protonated amine groups to adsorb strongly anionic species from diluted solutions. In this work, adsorption and thermochemical data on the interaction of the dye indigo carmine with chitosan in aqueous medium were found, in order to obtain new adsorption data on this relatively unexplored chitosan field. The studies were carried out by the batch method from 35 to 50 degrees C. The adsorption results were well fitted to both Langmuir and Freundlich adsorption models. The increase in the temperature decreased the adsorption of the dye. The enthalpy of interaction, when a monolayer of the dye was formed on the chitosan surface, delta(int)H, of -23.2 kJ mol(-1) was encountered for all temperature ranges studied. The spontaneity of the interaction is indicated by the delta(int)G values from -9.1 to -8.2 kJ mol(-1). Other thermodynamic quantities were also calculated and are discussed.     

Investigation of the factors affecting organic cation adsorption on some silicate minerals

In this study, the effects of some factors on the adsorption of a basic dye (methylene blue) on bentonite and sepiolite samples were studied. These factors are cation (Na(+) and Ca(2+)) saturation of the samples and pH and ionic strength of the dye solution. The adsorption data were found to conform to the Langmuir equation within the concentration range studied and Langmuir constants were determined for each of the samples. The adsorption capacities of the samples were found to increase with cation saturation. Changes in the pH of the dye solution had no significant influence on the adsorption capacity and adsorption capacities were found to decrease with increasing ionic strength. The maximum sorption capacity of methylene blue exceeded the cation exchange capacity of bentonite and sepiolite.     

Equilibrium studies of the sorption of Cu(II) ions onto chitosan

Chitosan is a polymer that can be obtained from the shells of seafood such as prawns, crabs, and lobsters. Chitosan has free amino groups, which can attract metal ions, and has been used as an adsorbent for the removal of metal ions from effluents. In this research, the sorption of copper ions from solution onto chitosan at two pHs has been investigated. DSC, TGA, surface area, SEM, and NMR studies have been used to report the pure physical states of chitosan and the chitosan-copper complex. The experimental isotherm data were analyzed using the Langmuir, Freundlich, and Redlich-Peterson equations. Correlation coefficients were determined for each isotherm analysis. Error functions have been used to determine the alternative single component parameters by nonlinear regression due to the inherent bias in using the correlation coefficient resulting from linearization. The error function method provided the best parameters for the isotherm equations in this system and is demonstrated for error comparison purposes.     

Effect of temperature,particle size and percentage deacetylation on the adsorption of acid dyes on chitosan

The adsorption of five acidic dyes on chitosan—a by-product from waste crustacean shell—has been studied. The equilibrium data have been studied using Langmuir, Freundlich and Redlich-Peterson equations. The best correlations are obtained using the Langmuir isotherm suggesting the mechanism involves one process step of dyes complexing with the free amino group. The effect of chitosan particle size was investigated and showed an increase in adsorption capacity with decreasing particle size indicating that the available external surface was an important factor. Increasing solution temperature resulted in an increase in adsorption capacity indicating an exothermic process with a negative ΔH. Finally, the effect of varying the percentage degree of deacetylation showed that from 52% to 97% resulted in decrease in the dye adsorption capacity suggesting that more amorphisation may cause changes in the internal structure of chitosan and reduce the capacity.     

溶菌酶分子印迹聚合物膜的制备及其吸附性能

以溶菌酶为模板蛋白质，结合分子印迹技术在硅烷化的基质玻片上制备了溶菌酶分子印迹聚合物膜。实验优化了溶菌酶聚合物膜的印迹体系，考察了溶菌酶分子印迹聚合物膜的吸附平衡时间、最大吸附量、特异识别能力、重复使用性以及对实际样品中溶菌酶的分离情况。结果表明，在最优条件下，制备的分子印迹聚合物膜对溶菌酶具有特异吸附能力，印迹因子为3.0，吸附平衡时间为5 min，吸附行为符合Langmuir吸附模型，理论最大吸附量为42.5 mg/g，实际样品中的吸附量为30 mg/g。且此印迹聚合物膜在重复使用5次后，最大吸附量仅下降了5%，具有良好的重复使用性。该方法为复杂生物样品中目标蛋白质的分离富集提供了一种快速、高效的手段。     

Single and Binary Dye Adsorption of Methylene Blue and Methyl Orange in Alcohol Aqueous Solution via Rice Husk Based Activated Carbon: Kinetics and Equilibrium Studies

The present work was mainly focused on the single and binary adsorption of methylene blue(MB) and methyl orange(MO) from alcohol aqueous solution over rice husk based activated carbon(RHAC). The study of single dye adsorption equilibrium experiments found that the Langmuir adsorption model was consistent with the adsorption behavior of RHAC on MB and MO, indicating that it was a single layer adsorption. The adsorption behavior conformed to the pseudo-second-order kinetic model. The binary dye adsorption experiments showed that the Langmuir-Freundlich model could be applied to describe the adsorption behavior of RHAC on MB and MO. Comparation with the single dye system, the adsorption capacity on the binary dye system was larger, and there was "competitive adsorption" and "synergistic adsorption" effects existed. Meanwhile, the pseudo-second-order kinetic model also fit for the binary dye adsorption behavior.     

Adsorption of anionic methyl orange dye by polyaniline,poly(o-methylaniline) and poly(o-methoxyaniline)

This study reports the effect of substituents in the ortho position of polyaniline on the adsorption capacity to remove the anionic dye methyl orange (MO) from an aqueous solution. The aim of this study is the synthesis of polyaniline (PANI) and its derivatives, poly-o-methylaniline (poly-o-toluidine, POT) and poly-o-methoxyaniline (poly-o-anisidine, POA) for the adsorption removal of MO dye. All polymers were obtained by oxidative polymerization of the corresponding monomers and characterized by scanning electron microscopy (SEM) and infrared spectroscopy (IR). The average particle size of the polymer was about 200 nm. The effect of various parameters such as pH, temperature, adsorption time and initial concentration was analyzed. It was found that the adsorption capacity for dye removal increases from 50.68 to 222.56 mg g⁻¹ for PANI, from 16.89 to 66.57 mg g⁻¹ for POT, and from 97.26 to 532.54 mg g⁻¹ for POA with an increase in the initial dye concentration from 5 up to 50 mg L⁻¹. For all polymers, the equilibrium state of MO adsorption was reached in 50 min. The results showed that MO adsorption on PANI, POT, and POA is well described by a pseudo second order kinetic model. Isothermal studies have shown that adsorption is in good agreement with the Langmuir isotherm model, as evidenced by higher values of correlation coefficients. Based on the data of thermodynamic studies, it was concluded that MO adsorption on PANI, POT, and POA is spontaneous and endothermic.     

壳聚糖插层蒙脱土复合材料吸附酸性染料的动力学和热力学研究

通过离子交换的方法将天然大分子壳聚糖引入蒙脱土的层间,利用XRD和TG对得到的复合材料进行表征。将该复合材料用于酸性黑10B的吸附,考查了pH值、染料起始浓度、吸附时间以及温度对吸附性能的影响。结果表明,吸附动力学实验数据符合准二级动力学模型。应用Langmuir和Freundlich两种模型描述吸附等温线,结果显示Langmuir模型的拟合效果更好。计算得到吸附过程的热力学参数△Go、△Ho和△So的值分别为-27.16kJ/mol(20℃)、-14.18kJ/mol和44.0J/mol.K,说明复合材料对酸性染料的吸附是一个自发进行的放热过程。     

Adsorption of reactive dyes on titania-silica mesoporous materials

This paper presents a study on the adsorption of two basic dyes, methylene blue (MB) and rhodamine B (RhB), from aqueous solution onto mesoporous silica-titania materials. The effect of dye structure, adsorbent particle size, TiO(2) presence, and temperature on adsorption was investigated. Adsorption data obtained at different solution temperatures (25, 35, and 45 degrees C) revealed an irreversible adsorption that decreased with the increment of T. The presence of TiO(2) augmented the adsorption capacity (q(e)). This would be due to possible degradation of the dye molecule in contact with the TiO(2) particles in the adsorbent interior. The adsorption enthalpy was relatively high, indicating that interaction between the sorbent and the adsorbate molecules was not only physical but chemical. Both Langmuir and Freundlich isotherm equations were applied to the experimental data. The obtained parameters and correlation coefficients showed that the adsorption of the two reactive dyes (MB and RhB) on the adsorbent systems at the three work temperatures was best predicted by the Langmuir isotherm, but not in all cases. The kinetic adsorption data were processed by the application of two simplified kinetic models, first and second order, to investigate the adsorption mechanism. It was found that the adsorption kinetics of methylene blue and rhodamine B onto the mesoporous silica-titania materials surface under different operating conditions was best described by the first-order model.     

Selective Removal of the Emerging Dye Basic Blue 3 via Molecularly Imprinting Technique

A molecularly imprinting polymer (MIP) was synthesized for Basic Blue 3 dye and applied to wastewater for the adsorption of a target template. The MIPs were synthesized by bulk polymerization using methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA). Basic Blue 3 dye (BB-3), 2,2′-azobisisobutyronitrile (AIBN) and methanol were used as a functional monomer, cross linker, template, initiator and porogenic solvent, respectively, while non-imprinting polymers (NIP) were synthesized by the same procedure but without template molecules. The contact time was 25 min for the adsorption of BB-3 dye from 10 mL of spiked solution using 25 mg polymer. The adsorption of dye (BB-3) on the MIP followed the pseudo-second order kinetic (k₂ = 0.0079 mg·g⁻¹·min⁻¹), and it was according to the Langmuir isotherm, with maximum adsorption capacities of 78.13, 85.4 and 99.0 mg·g⁻¹ of the MIP at 283 K, 298 K and 313 K, respectively and 7 mg·g⁻¹ for the NIP. The negative values of ΔG° indicate that the removal of dye by the molecularly imprinting polymer and non-imprinting polymer is spontaneous, and the positive values of ΔH° and ΔS° indicate that the process is endothermic and occurred with the increase of randomness. The selectivity of the MIP for BB-3 dye was investigated in the presence of structurally similar as well as different dyes, but the MIP showed higher selectivity than the NIP. The imprinted polymer showed 96% rebinding capacity at 313 K towards the template, and the calculated imprinted factor and Kd value were 10.73 and 2.62, respectively. In this work, the MIP showed a greater potential of selectivity for the template from wastewater relative to the closely similar compounds.     

Cationic dye adsorption by poly(N-isopropylacrylamide/maleic acid) copolymeric hydrogels prepared by gamma rays

N-isopropylacrylamide/maleic acid hydrogels containing different quantities of maleic acid have been synthesized with γ-radiation. The hydrogels were used in experiments on swelling, diffusion and adsorption of a cationic dye methylene blue. The diffusion of MB into the hydrogels was found to be the non-Fickian type. The factors influencing adsorption capacity of the hydrogel such as gel composition, and irradiation dose were systematically investigated. The equilibrium data for dye adsorption was better described by the Freundlich isotherm than Langmuir isotherm model. The kinetic studies showed that the pseudo-second-order kinetic model fits better than the data obtained from pseudo-first-order model.     

3-氨基苯硼酸为功能单体在壳聚糖上印迹牛血清白蛋白的研究

以壳聚糖为载体, 3-氨基苯硼酸为功能单体对牛血清白蛋白进行了分子印迹的研究, 并对吸附过程进行Langmuir等温吸附模型的数据处理. 结果表明, 印迹聚合物上形成了对于模板分子有较高的吸附容量和选择性的识别位点, Langmuir等温吸附平衡常数为49.5 mL/mg, 结合位点的最大表观结合量为16.3 mg/g, 证明了该印迹聚合物对于牛血红蛋白和溶菌酶这些非模板蛋白的吸附不具有选择性.