乙二胺丙酰化交联壳聚糖微球对甲基橙的吸附性能

通过丙烯酰化交联壳聚糖微球（AGCS）上的丙烯酰基团与乙二胺的Michael加成反应，制备乙二胺丙酰化交联壳聚糖微球（EAGCS）。分别采用傅里叶变换红外光谱（FT-IR）、X射线光电子能谱（XPS）和X射线衍射（XRD）表征了EAGCS的结构，利用激光粒度分析仪进行了粒径分布分析，考察了甲基橙（MO）溶液pH、温度、浓度和EAGCS用量对EAGCS吸附性能的影响。结果表明：EAGCS为球形，微球的体积平均粒径为57.4 μm，粒径分布系数1.53；在最佳条件下，EAGCS的吸附去除率为99.6%，吸附容量可达545.40 mg·g^-1，吸附过程属于自发放热过程，吸附动力学符合二级动力学，吸附过程可采用Langmuir和Freundlich等温吸附模型来描述。     

不同修饰剂对β-环糊精微球吸附性能的影响

以β-环糊精为原料,通过传统的反相乳液聚合法合成β-环糊精微球,选择壳聚糖和四甲基氢氧化铵分别对其进行修饰,考察溶液的搅拌时间、吸附体系的温度、pH等条件对β-环糊精微球及其衍生物吸附甲基橙的影响。结果显示,β-环糊精微球对甲基橙吸附效果较好,修饰改性后,吸附效果增强,四甲基氢氧化铵修饰的β-环糊精微球吸附效果优于壳聚糖修饰后β-环糊精微球。     

Facile preparation of EDTA‐functionalized chitosan magnetic adsorbent for removal of Pb(II)

A novel magnetic adsorbent (EDTA /chitosan/ PMMS) was facilely prepared by reacting chitosan with EDTA anhydride in presence of PEI ‐ coated magnetic microspheres. The as‐synthesized EDTA/ chitosan /PMMS was characterized by XRD, SEM, TGA, FT‐IR , and VSM, and then employed in removal of heavy metals of Pb(II) from aqueous solution. The results of the batch adsorption experiments revealed that the adsorbents had extremely high uptake capacities for Pb(II) in the pH range of 2 to 5.5, and the adsorption kinetics for EDTA/ chitosan /PMMS was consistent with the pseudo – second ‐ order kinetic model. Moreover, its equilibrium data were fitted with the Langmuir isothermal model well, which indicated that the adsorption mechanism was a homogeneous monolayer chemisorptions process. The maximum adsorption capacity of EDTA/ chitosan /PMMS for Pb(II) was found to be 210 mg g ^{? 1} at pH 4 (30 ° C), and further reuse experiments results suggested that EDTA /chitosan/ PMMS could be a potential recyclable magnetic adsorbent in the practical wastewater treatment. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42384.     

Human serum albumin (HSA) adsorption with chitosan microspheres

In this study, chitosan microspheres were prepared and characterized for adsorption of human serum albumin (HSA) as affinity sorbent. The chitosan microspheres were obtained with a “suspension crosslinking technique” in the size range of 30–700 μm by using a crosslinker, i.e., glutaraldehyde. The chitosan microspheres used in HSA adsorption studies were having the average size of 170 ± 81 μm. Adsorption medium pH and the initial HSA concentration in the adsorption medium were changed as 4.0–7.0 and 0.5–2.0 mg HSA/mL, respectively, to investigate the HSA adsorption capacity of chitosan microspheres. Maximum HSA adsorption (i.e., 11.35 mg HSA/g chitosan microspheres) was obtained at pH 5.0 and 1.5 mg HSA/mL of the initial HSA concentration in the adsorption medium was obtained as the saturation value for HSA adsorption. A very common dye ligand, i.e., Cibacron Blue F3GA was attached to the chitosan microspheres to increase the HSA adsorption capacity. Actually, the HSA adsorption capacity was increased up to 15.35 mg HSA/g chitosan microspheres in the case of Cibacron Blue F3GA attached to chitosan microspheres used. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 86: 3035–3039, 2002     

Adsorption of methyl orange from aqueous solution by composite magnetic microspheres of chitosan and quaternary ammonium chitosan derivative

Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative (CHMMs) were prepared by inverse suspension method, and used for the methyl orange (MO) removal from aqueous solutions. The CHMMs were characterized by a scanning electron microscope, a transmission electron microscope, and Fourier transform infrared spectroscopy, respectively. Compared with the chitosan beads, the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size. The MO adsorption by CHMMs was investigated by batch adsorption experiments. The adsorption kinetics was conformed to the pseudo second-order kinetics equation. The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K. Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change (ΔH°) of 99.44 kJ·mol^-1. The CHMMs had a stable performance for MO adsorption in the pH range of 4-10, but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction. A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs. The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.     

甲基橙印迹磁性壳聚糖聚合物的制备及吸附特性

以通过溶胶-凝胶法自制的Fe₃O₄@壳聚糖（CTS）微球为载体,甲基橙（MO）为模板分子,采用水溶液聚合法制得磁性壳聚糖表面分子印迹聚合物（MMIPs）。通过SEM、XRD、FT-IR和VSM表征了MMIPs的结构和性能,并探究了其对MO的识别与选择性吸附特性。研究表明：与非印迹聚合物（NIMPs,饱和吸附量为20.56 mg/g）相比,在相同条件（pH值6.5、25℃）下,MMIPs对MO具有明显的特异性吸附能力,在60 min左右吸附饱和,饱和吸附量（Q_e）可达113.16 mg/g;MMIPs对MO的吸附符合Langmuir等温吸附模型和准二级吸附动力学模型;在其他干扰染料的存在下,MMIPs的选择性系数（K）最高可达2.85,对MO具有选择识别性;此外,吸附完成后MMIPs可在磁场作用下快速分离,解吸附后循环使用5次,吸附率均在90%以上。     

Zeolite X/chitosan hybrid microspheres and their adsorption properties for Cu(II) ions in aqueous solutions

The preparation of zeolite X/chitosan (CS) hybrid microspheres for efficient removal of Cu(II) ions by an impregnation-gelation-hydrothermal synthesis technique is reported here. Characterizations by various techniques indicate that the microspheres show porous structures and intimate interaction between zeolite and CS. The adsorption experiments are performed to evaluate the adsorption capacity of zeolite X/CS hybrid microspheres and comparisons are made with binderless zeolite X microspheres, pure CS microspheres and mechanical mixed zeolite X/CS microspheres. The effects of Cu(II) solution concentration and the pH are investigated. The results indicate that zeolite X/CS hybrid microspheres with the zeolite content of 60 wt% show the highest adsorption capacity, which is 90 mg/g at the initial Cu(II) concentration of 10 mg/L and 150.4 mg/g at Cu(II) concentration of 500 mg/L. The adsorption capacity increases with increasing initial pH and reaches a maximum at pH 5.5 in the range of 0–6.0. The equilibrium adsorption data are well described by the Langmuir isotherm model, exhibiting a maximum adsorption capacity of 152.0 mg/g, and the kinetic data are well fitted with the pseudo-second-order equation. Complete removal of Cu(II) ions can be obtained even at very low concentrations. The microspheres show high adsorption capacity and efficiency for Cu(II) ions, exhibiting potential practical application in the treatment of water pollution of heavy metal ions.     

Effect of heparin coating on epichlorohydrin cross-linked chitosan microspheres on the adsorption of copper (II) ions

Epichlorohydrin cross-linked chitosan microspheres (CS) and chitosan–heparin polyelectrolyte complex microspheres (CSH) were used in the adsorption of copper (II) ions in aqueous solution. The chitosan microspheres were prepared by the phase inversion method. The use of a cross-linking agent improved the resistance to acidic medium. Polyelectrolyte complex microspheres were prepared by impregnating heparin in cross-linked chitosan microspheres. The microspheres were characterized by IR, TGA and DSC. A study on the effect of the pH on the adsorption of copper (II) ions showed that the optimum pH for both CS and CSH microspheres was 6.0. From a kinetic evaluation, it could be established that the adsorption equilibrium was achieved after 8 h for CS and 25 h for CSH microspheres. The adsorption isotherms were interpreted using Langmuir and Freundlich mathematical models. The results revealed that experimental data of CS was best adjusted by Langmuir model, with maximum capacity of surface saturation equal to 39.31 mg g⁻¹. On the other hand, Langmuir and Freundlich models provided a good fit for adsorption by CSH and the adsorption capacity was 81.04 mg g⁻¹. The interactions between copper (II) ions and both CS and CSH were confirmed by electron paramagnetic resonance spectroscopy, which revealed the formation of a square-planar complex with tetrahedral distortion on the surface of the adsorbents.     

羧甲基壳聚糖微球对曙红Y的吸附研究

以壳聚糖粉末为原料,戊二醛进行交联、羧甲基化,制得羧甲基壳聚糖微球。采用SEM对壳聚糖微球的形貌、大小进行了表征,研究羧甲基壳聚糖微球对曙红Y的吸附性能。探讨吸附剂用量、吸附时间、曙红Y的初始浓度、pH、温度对脱色率的影响,研究吸附等温曲线和动力学方程。实验结果表明,曙红Y初始浓度增加时,吸附量也增加,直到吸附饱和,羧甲基壳聚糖的饱和吸附量为75 mg/g;相同条件下,吸附剂用量增加时,平衡吸附量减小,去除率增加。298 K,吸附剂投加量为1 g,pH=7.0,吸附时间为40 min时,初始浓度为560 mg/L的曙红Y染料的去除率可以达到90%以上。符合Langmuir等温方程和二级吸附动力学方程。     

Preparation,characterization, and adsorption properties of chitosan microspheres crosslinked by formaldehyde for copper (II) from aqueous solution

The chitosan microspheres crosslinked by formaldehyde were prepared by spray drying method and used as an adsorbent for copper (II) from aqueous solution. A batch adsorption system was applied to study the adsorption of copper (II) from aqueous solution by chitosan microspheres. The maximum adsorption capacity of the chitosan microspheres for copper (II) was 144.928 mg/g at pH 6.0. Langmuir adsorption model was found to be applicable in interpreting the adsorption process. To elucidate the adsorption mechanism, the chitosan microspheres before and after copper (II) adsorption were further characterized by Fourier transform infrared spectra, zeta potential analysis, and scanning electron microscope. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation of polyethersulfone/sulfonated polyethersulfonephenylethane microspheres and its application for the adsorption of bisphenol A

A novel kind of sulfonated polyethersulfonephenylethane (SPESPE) was successfully synthesized firstly in this work. Then the SPESPE was introduced in polyethersulfone (PES) microspheres prepared by the electrospraying technique. The microspheres were applied to adsorbing bisphenol A (BPA) from its aqueous solution. Compared with the PES microspheres, the adsorption capacity of PES/SPESPE microspheres for BPA was increased significantly. Furthermore, the adsorption capacity of PES/SPESPE microspheres was enhanced by increasing the amounts of SPESPE in the microspheres. The pH of solution had influence on the adsorption capacity of PES/SPESPE microspheres. The kinetic data of adsorption were found to follow pseudo‐second‐order model. The Freundlich isotherm model was suitable to describe the equilibrium adsorption data. The microspheres also showed excellent regeneration and reuse ability. These results indicated that the PES/SPESPE microspheres have the potential to be used in environmental application. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43066.     

Adsorption of Methylene Blue on Poly (Methacrylic Acid) Modified Chitosan and Photocatalytic Regeneration of the Adsorbent

The preparation of poly(methacrylic acid) modified chitosan microspheres (PMAA-GLA-CTS) and its application for the removal of cationic dye, methylene blue (MB), in aqueous solution in a batch system were described. The modified chitosan was characterized using FTIR and XPS analysis. The effects of the pH of the solution, contact time, and initial dye concentration were studied. The adsorption capacity of the microspheres for MB increased significantly after the modification as a large number of carboxyl groups were introduced. The equilibrium process was better described by the Langmuir rather than the Freundlich isotherm. According to the Langmuir equation, the maximum adsorption capacity was 1 g · g^?1 for MB. Kinetic studies showed better correlation coefficients for a pseudo-second-order kinetic model, confirming that the sorption rate was controlled by a chemisorption process. Photocatalytic regeneration of spent PMAA-GLA-CTS using UV/TiO₂ is effective. Further, the regenerated PMAA-GLA-CTS exhibits 90% efficiency for a subsequent adsorption cycle with MB aqueous solutions.     

Biosorption of chromium (III) by orange (Citrus cinensis) waste: Batch and continuous studies

The present study explores the ability of orange waste biomass to remove Cr (III) from aqueous solutions. Batch kinetic and isotherm studies were carried out on a laboratory scale to evaluate the adsorption capacity of orange waste. The effects of particle size, adsorbent dose and solution pH on Cr (III) removal were also studied. The results showed that the higher the adsorbent dosage and the pH, the higher the percentage of metal removal. No significant influence of particle size on sorption capacity was observed in the experimental conditions studied. A kinetic study revealed that the adsorption of Cr (III) onto orange waste was a gradual process and equilibrium was reached within 3 days. A pseudo-second order model was the most appropriate to describe the kinetic experimental data. Equilibrium assays displayed a maximum sorption capacity ranging from 0.57 mmol/g to 1.44 mmol/g when the pH increased from 3 to 5, according to the Sips model, which along with the Redlich–Peterson equation, is very suitable for correlating equilibrium data. The use of the studied adsorbent in the removal of chromium in continuous mode was successful and the breakthrough curves were adequately represented by BDST model. Due to the slow kinetics of chromium sorption onto orange waste, the sorption capacity in batch assays was higher than that in continuous assays.     

Removal of copper(II) from an aqueous solution with copper(II)‐imprinted chitosan microspheres

Ion‐imprinted chitosan (CS) microspheres (MIPs) were prepared with Cu(II) as a template and epichlorohydrin as a crosslinker for the selective separation of Cu(II) from aqueous solution. The microspheres showed a higher adsorption capacity and selectivity for the Cu(II) ions than nonimprinted chitosan microspheres (NMIPs) without a template. The results show that the adsorption of Cu(II) on the CS microspheres was affected by the initial pH value, initial Cu(II) concentration, and temperature. The kinetic parameters of the adsorption process indicated that the adsorption followed a second‐order adsorption process. Equilibrium experiments showed very good fits with the Langmuir isotherm equation for the monolayer adsorption process. The maximum sorption capacity calculated from the Langmuir isotherm was 201.66 mg/g for the Cu–MIPs and 189.51 mg/g for the NMIPs; these values were close to the experimental ones. The selectivity coefficients of Cu(II) and other metal ions on the NMIPs indicated a preference for Cu(II). © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

壳聚糖固化单宁微球的制备及其吸附性能

5 g单宁酸与10 g壳聚糖微球在100 mL pH=7的溶液中反应6 h,再用0.06 mol/L环氧氯丙烷在pH=10,50℃反应4 h制得壳聚糖固化单宁微球,每克壳聚糖微球固载单宁量为0.27 g。采用扫描电镜和红外光谱对微球进行了表征,考察了微球的溶胀性能及对金属离子的吸附性能。研究表明,通过此法制得的壳聚糖固化单宁微球具有表面粗糙,内部疏松多孔的结构。与壳聚糖微球相比,壳聚糖固化单宁微球在溶液中的溶胀性减小,在pH=5及9时,分别减小了63%和50%。对金属离子的吸附容量增大,对Cd2+的吸附容量从0.6 mmol/g提高到2.2 mmol/g,提高了2.66倍。     

交联壳聚糖复合微球对F-的吸附性能研究

以壳聚糖(CTS)包合氧化铝经戊二醛交联反应制备了复合微球作为氟离子吸附剂。主要研究了复合微球对F-的吸附模型和吸附动力学,并考察了再生次数对吸附容量的影响。结果表明复合微球对F-有很强的吸附作用和较快的吸附速率;吸附行为符合Freundlich模型,为吸热过程,吸附表观活化能△E=53.71kJ/mol;复合微球经碱液洗脱再生后能够多次使用。     

表面修饰聚乙烯亚胺的壳聚糖微球对十二烷基苯磺酸钠的吸附特性

采用乳化交联法制备交联壳聚糖微球(CCS),在其表面接枝聚乙烯亚胺(PEI),得到系列具有不同离子交换容量(IEC)的PEI修饰交联壳聚糖微球(PEI-CCS),对其进行表征,考察了其对十二烷基苯磺酸钠(SDBS)的静态吸附特性. 结果表明,PEI-CCS平均粒径为85 mm,IEC最高达1275 mmol/g,远高于CCS的418 mmol/g. 酸性条件下,PEI-CCS的胺基质子化,带正电荷,能与溶液中的阴离子吸附结合,对SDBS有良好的吸附能力. 吸附过程自发放热,可用准二级动力学模型和Langmuir吸附等温模型描述. PEI-CCS对SDBS的最大吸附量随IEC增加而增大,IEC=1275 mmol/g的PEI-CCS的最大吸附量为1487.61 mg/g,是CCS最大吸附量(510.20 mg/g)的2.92倍,吸附-脱附7次循环后,吸附量下降17.8%. PEI-CCS具有良好的重复使用性.     

Radiation-initiated chitosan-based double network hydrogel: Synthesis,characterization, and adsorption of methylene blue

A novel chitosan (CTS)-based double network Poly(2-acrylaMido-2-Methyl-1-propanesulfonic acid)/Polyacrylamide/CTS hydrogel was synthesized by irradiation initiated. Laponite RD (RD) was used as both dopant and the cross-linking agent. Then the fabricated hydrogel was applied as an efficient adsorbent to remove the methylene blue (MB) in an aqueous solution. This hydrogel has both high strength and good adsorption properties for MB. The results from Brunauer–Emmett–Teller method confirmed that the hydrogel has a large specific surface area (96 m²/g) and developed pore structure, which is available for the contact between the adsorbent and dye molecules. In the adsorption process, the RD provides plenty of negative charges as adsorption sites for MB molecules. The influence of pH, temperature, and adsorbent dose on the adsorption performance was investigated in detail. The experimental data fit well with the pseudo-second-order kinetic model and Langmuir isotherm. Besides, the mechanical strength of the hydrogel was also investigated in this work.     

空心壳聚糖微球对二甲酚橙的吸附性能研究

采用反相悬浮交联法制备了具有空壳结构的壳聚糖微球。利用静电引力对二甲酚橙的进行吸附研究。通过分光光度法探讨了溶液初始DH值、吸附时间、二甲酚橙的初始质量浓度、吸附剂的用量及其粒径大小对二甲酚橙的吸附率的影响。结果表明：在DH值为4．90及常温下,二甲酚橙溶液的初始质量浓度为32mg／L时,可达到吸附平衡,此时的吸附剂用量为0．03g／100mL,吸附平衡时间约为2h,吸附率可高达93．6％。结果表明,此微球具有很强的吸附能力,而且平衡时间快,并且具有一定的重复利用的性能,是一类很值得开发的新型吸附分离材料。     

静电纺壳聚糖/PVA纳米纤维膜对甲基橙的吸附特性

以静电纺丝制备的壳聚糖(CS)/聚乙烯醇(PVA)纳米纤维膜为吸附剂,研究了反应时间、甲基橙初始质量浓度、膜吸附剂用量和pH值对吸附甲基橙染料的影响,并通过吸附动力学行为和吸附等温线研究了其吸附机制。结果表明:当pH值在5～9之间、甲基橙初始质量浓度为100 mg/L、吸附剂用量为30 mg、反应时间为60～120 min之间时,吸附效果最佳且吸附平衡时间为3 h;CS/PVA膜对甲基橙的吸附既有物理吸附也有化学吸附,化学吸附占主导作用,CS/PVA膜对甲基橙的吸附符合Langmuir等温线和拟二级动力学模型。