壳聚糖对酸性艳橙GS的吸附平衡与动力学研究

研究了壳聚糖(CS)对水溶液中的酸性艳橙GS(ABO)染料的吸附性能,考察了温度、pH值、壳聚糖分子量对吸附性能的影响.不同温度下的动力学数据分别采用拟一级、拟二级、内扩散方程进行关联;不同温度下壳聚糖对酸性艳橙GS的吸附平衡数据分别用1angmuir、Freundlich、Tempkin模型拟合.结果表明:该吸附过程...     

正癸酸修饰磁性纳米Fe3O4对溶菌酶的吸附研究

以沉淀法制备了正癸酸修饰磁性纳米Fe3O4,采用XRD、TEM和FT-IR对修饰前后的磁性纳米粒子的形态、结构进行了表征。将修饰后的磁性纳米粒子用于对溶菌酶蛋白进行吸附分离,研究了溶液的pH、温度、时间、溶菌酶初始浓度、离子强度等因素对吸附过程的影响。结果表明:pH=10.7,吸附温度为25℃,吸附时间为2.0 h,溶菌酶初始浓度为0.30 mg·mL-1,最大吸附容量为35.0 mg·g-1。修饰后的磁性纳米粒子用于从鸡蛋清中提取溶菌酶,纯化倍数为30.9,酶活力收得率为73.0%。     

Adsorption of acid red 114 and reactive black 5 in aqueous solutions on dendrimer‐conjugated magnetic nanoparticles

The adsorption of the dyes Acid Red 114 and Reactive Black 5 in aqueous solutions on polyhydroxyl dendrimer magnetic nanoparticles (Fe₃O₄@SiO₂‐TRIS) was studied in a batch system. The Fe₃O₄@SiO₂‐TRIS NPs were characterized by Fourier transform infrared spectroscopy, X‐ray diffraction, and transmission electron microscopy. Experiments were performed under different conditions such as the initial dye concentration, adsorbent dose, and pH. The pseudo‐second‐order model provided a very good fit for the two anionic dyes. The Langmuir and Freundlich adsorption models were used to describe the equilibrium isotherms at different temperatures, and the former agreed very well with the experimental data. However, the adsorption capacity of Fe₃O₄@SiO₂‐TRIS NPs was reduced during surface modification, which could be due to the dye occupying the binding sites of the dendrimer. Thermodynamic parameters, namely the change in free energy (ΔG⁰), enthalpy (ΔH⁰), and entropy (ΔS⁰), were also determined.     

Magnetically assisted removal and separation of cationic dyes from aqueous solution by magnetic nanocomposite hydrogels

Magnetic poly(acrylic acid‐acrylamide‐butyl methacrylate) (P(AAB)) nanocomposite hydrogels were prepared and used as adsorbents for removal and separation of cationic dyes from aqueous solution. These magnetic P(AAB) nanocomposite hydrogels were characterized by scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM). It was found that these magnetic P(AAB) nanocomposite hydrogels had magnetic responsive characters. The dynamic swelling, removal, and separation of cationic dye, crystal violet (CV), and basic magenta (BM) by these magnetic nanocomposite hydrogels were studied. The adsorption capacity and isotherm studies of cationic dyes onto magnetic P(AAB) nanocomposite hydrogels have been evaluated. The magnetic P(AAB) nanocomposite hydrogels containing Fe₃O₄ particles can be easily manipulated in magnetic field for removal and separation of cationic dyes from aqueous solution. Adsorption process agreed very well with the Langmuir and Freundlich models. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of carboxyl‐functionalized magnetic nanoparticles for adsorption of malachite green from water: Kinetics and thermodynamics studies

Magnetic carboxyl‐coated silica iron oxide nanoparticles (Fe₃O₄@SiO₂‐COOH NPs) were successfully synthesized, characterized, and then applied as a nano‐adsorbent for removal of malachite green (MG) from aqueous solutions. According to the experimental results, about 97.5% of MG could be removed from aqueous solutions using an adsorbent amount of 0.5 g/L at pH = 9 in 120 min. The kinetics and equilibrium adsorptions is well‐described by the pseudo‐second‐order kinetics and Langmuir model with the maximum absorption capacity of 263.16 mg/g, respectively. Thermodynamic studies showed that the adsorption of the hazardous MG dye was spontaneous and endothermic with a random process.     

Enhanced adsorption performance of a novel Fe‐Mn‐Zr metal oxide nanocomposite adsorbent for anionic dyes from binary dye mix: Response surface optimization and neural network modeling

A novel adsorbent, Fe‐Mn‐Zr metal oxide nanocomposite was synthesized and investigated for removal of methyl orange (MO) and eosin yellow (EY) dyes from binary dye solution. The magnetic nanocomposite has shown surface area of 143.01 m²/g and saturation magnetization of 15.29 emu/g. Optimization was carried out via response surface methodology (RSM) for optimizing process variables, and optimum dye removal of 99.26% and 99.55% were obtained for MO and EY dye, respectively with contact time 62 min, adsorbent dose 0.45 g/l, initial MO concentration 11.0 mg/l, and initial EY concentration 25.0 mg/l. A feed forward back propagation neural network model has shown better prediction ability than RSM model for predicting MO and EY dye removal (%). Adsorption process strictly follows Langmuir isotherm model, and enhanced adsorption capacities of 196.07 and 175.43 mg/g were observed for MO and EY dye, respectively due to synergistic effects of physicochemical properties of trimetal oxides. Surface adsorption and pore diffusions are the mechanisms involved in the adsorption as revealed from kinetic studies.     

Synthesis,characterization and dyeing assessment of novel acid azo dyes and mordent acid azo dyes based on 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid on wool and silk fabrics

Novel acid mono azo and mordent acid mono azo dyes were synthesized by the coupling of diazonium salt solution of different aromatic amines with 2-hydroxy-4-methoxybenzophenone-5-sulfonic acid. The resulting dyes were characterized by spectral techniques like elemental analysis, IR, ¹H-NMR and UV visible spectroscopy. The dyeing performance of all the dyes was evaluated on wool and silk fabrics. The dyeing of chrome pre-treated wool and silk fabrics showed better hues on mordented fabrics. Dyeing of wool and silk fabrics resulted in pinkish blue to red shades with very good depth and levelness. The dyed fabrics showed excellent to very good light, washing, perspiration, sublimation and rubbing fastness.     

Green synthesis of silver nanoparticles using Eucalyptus comadulensis leaves extract and its immobilization on magnetic nanocomposite (GO-Fe3O4/PAA/Ag) as a recoverable catalyst for degradation of organic dyes in water

The magnetically recyclable graphene oxide-Fe₃O₄/polyallylamine (PAA)/Ag nanocatalyst was prepared via a green route using Eucalyptus comadulensis leaves extract as both reducing and stabilizing agent. The catalytic activity of this nanocatalyst was investigated for the reduction reaction of methylene blue and methyl orange in the presence of NaBH₄ in aqueous medium at room temperature. The prepared nanocatalyst was characterized by different methods such as Fourier transformed infrared spectroscopy, X-ray diffraction, scanning electron microscopy–energy dispersive X–ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometer, transmission electron microscopy, and UV–visible spectroscopy. The results show that graphene oxide/PAA/Ag nanocatalyst has good activity and recyclability, and can be reused several times without major loss of activity in the reduction process. The apparent rate constants of the methyl orange (MO) and methylene blue (MB) were calculated to be 0.077 s⁻¹ (3 mg of catalyst) and 0.15 s⁻¹ (2 mg of catalyst), respectively.     

Preparation and characterization of magnetic chitosan nanocomposites for removal of Cu2+ from aqueous solution

In this article, highly efficient magnetic chitosan nanoparticles were prepared by the glutaraldehyde cross-linking method and then chemically-modified with amino groups through reaction between triethylenetramine and glycidyl methacrylate. The adsorption kinetics and isotherms of these novel adsorbents fit the pseudo-second-order model and the Langmuir model. The maximum adsorption capacities were 293?mg/g at pH?=?4.3 and t?=?1.4 hours. The rate-limiting step was the chemical adsorption. Further recycling experiments showed that the adsorbent provided the potential regeneration and reuse after adsorbing Cu²⁺. All the experimental results demonstrated that the adsorbent had a potential application in Cu²⁺ removal from wastewater.     

Fabrication and characterization of CMC‐based magnetic superabsorbent hydrogel nanocomposites for crystal violet removal

In this research work, novel magnetic superabsorbent hydrogel nanocomposites (MSHNs) based on carboxymethyl cellulose were prepared via a facile “one‐pot” two step approach. Magnetic iron oxide nanoparticles were in situ synthesized and incorporated into carboxymethyl cellulose/poly(acrylic acid) polymer hydrogel. The morphology and chemical composition of MSHNs as well as the presence of magnetic iron oxide nanoparticles were evaluated by using Fourier transform infrared, scanning electron microscopy, transmission electron microscopy, X‐Ray diffraction, ultraviolet–visible spectroscopy, thermogravimetric analysis, and vibrating sample magnetometer. The effect of different reaction parameters on the swelling capacity of MSHNs was investigated. Furthermore, batch adsorption experiments of crystal violet dye onto MSHNs were studied by varying solution pH, initial dye concentration, and temperature. Evaluation of thermodynamic parameters of crystal violet adsorption confirmed that the adsorption was spontaneous and endothermic process in nature. The equilibrium study revealed that the dye adsorption behavior of MHSNs followed the Redlich‐Peterson isotherm model. Finally, the dye adsorption experiment data was well fitted by the pseudo‐second‐order kinetic model with the regression coefficient (R²) of 0.9979. Our results suggest that the MHSNs with facile preparation method, high swelling capacity, and high dye adsorption capacity may be used as promising adsorbents for fast removal of various dyes from aqueous solutions. Copyright © 2016 John Wiley & Sons, Ltd.     

Adsorption of cinnabarinic acid from culture fluid with magnetic microbeads

In this study, antimicrobial pigment cinnabarinic acid (CA) was produced from Pycnoporus cinnabarinus in laboratory‐scale batch cultures. Magnetic poly(ethylene glycol dimethacrylate‐N‐methacryloyl‐l‐tryptophan methyl ester) [m‐poly(EGDMA‐MATrp)] beads (average diameter = 53–103 µm) were synthesized by copolymerizing of N‐methacryloyl‐l‐tryptophan methyl ester (MATrp) with ethylene glycol dimethacrylate (EGDMA) in the presence of magnetite (Fe₃O₄) and used for the adsorption of CA. The m‐poly(EGDMA‐MATrp) beads were characterized by N₂ adsorption/desorption isotherms (Brunauer Emmet Teller), X‐ray photoelecron spectroscopy, scanning electron microscopy, infrared spectroscopy, thermal gravimetric analysis, electron spin resonance and swelling studies. The efficiency of m‐poly(EGDMA‐MATrp) beads for separation of CA from culture fluid was evaluated. The effects of pH, initial concentration, contact time and temperature on adsorption were analyzed. The maximum CA adsorption capacity of the m‐poly(EGDMA‐MATrp) beads was 272.9 mg g⁻¹ at pH 7.0, 25 °C. All the isotherm data can be fitted with the Langmuir, Freundlich and Dubinin–Radushkevich isotherm models. The adsorption process obeyed pseudo‐second‐order kinetic model. Thermodynamic parameters ΔH = 5.056 kJ mol⁻¹, ΔS = 52.44 J K⁻¹ mol⁻¹ and ΔG = −9.424 kJ mol−¹ to ‐11.27 kJ mol−¹ with the rise in temperature from 4 to 40 °C indicated that the adsorption process was endothermic and spontaneous. Copyright © 2015 John Wiley & Sons, Ltd.     

新型交联壳聚糖树脂的制备及其对苯甲酸的吸附行为研究

以壳聚糖为原料,甲醛为预交联剂,环氧氯丙烷为交联剂,通过反相悬浮交联法制备出新型壳聚糖树脂,并用红外光谱和扫描电镜对其结构进行表征.测定了不同温度下新制备树脂自水中吸附苯甲酸的等温线,计算了吸附过程的热力学参数.并用Freundlich方程对实验数据进行拟合,发现该方程适用于所研究的吸附体系.体系的热力学与吸附机理密切相关,当苯甲酸浓度较低时,吸附为放热过程,体系熵减少,降温有利于吸附;当苯甲酸浓度较高时,吸附为吸热过程,体系熵增加,升温有利于吸附.     

槲皮素磁性分子印记聚合物的制备及其吸附性能

以槲皮素(Qu)为模板分子、N-乙烯基吡咯烷酮(NVP)和丙烯酸(AA)为功能单体、N,N′-亚甲基双丙烯酰胺(MBA)为交联剂、H2O2-Vc为引发剂、KH570修饰的Fe3O4纳米颗粒为磁性载体,借助表面分子印迹技术制备了能够对Qu进行特异性识别的槲皮素磁性分子印迹聚合物(Qu-MMIPs)。利用X射线衍射仪(XRD)、透射电子显微镜(TEM)、傅里叶变换红外光谱仪(FT-IR)、振动样品磁强计(VSM)和紫外-可见分光光度计(UV-Vis)对样品进行了结构和性能表征。结果表明:Fe3O4磁性载体表面已成功包覆了分子印迹聚合物。与化学组成相同的磁性非印迹聚合物(Qu-MNIPs)相比,Qu-MMIPs对Qu有较高的吸附选择性。静态吸附平衡实验和Scatchard分析结果表明,Qu-MMIPs中存在两类不同的结合位点,平衡解离常数分别为1.646×10-6 mol/L和6.387×10-6 mol/L,最大吸附量分别为23.041mg/g和29.923mg/g。     

One-Step Preparation of Chitosan-Based Magnetic Adsorbent and Its Application to the Adsorption of Inorganic Arsenic in Water

Chitosan is a kind of biodegradable natural polysaccharide, and it is a very promising adsorber material for removing metal ions from aqueous solutions. In this study, chitosan-based magnetic adsorbent CMC@Fe₃O₄ was synthesized by a one-step method using carboxymethyl chitosan (CMC) and ferric salts under relatively mild conditions. The Fe₃O₄ microspheres were formed and the core–shell structure of CMC@Fe₃O₄ was synthesized in the meantime, which was well characterized via SEM/TEM, XRD, VSM, FT-IR, thermo gravimetric analysis (TGA), XPS, size distribution, and zeta potential. The effects of initial arsenic concentration, pH, temperature, contact time, and ionic strength on adsorption quantity of inorganic arsenic was studied through batch adsorption experiments. The magnetic adsorbent CMC@Fe₃O₄ displayed satisfactory adsorption performance for arsenic in water samples, up to 20.1 mg/g. The optimal conditions of the adsorption process were pH 3.0, 30−50 °C, and a reaction time of 15 min. The adsorption process can be well described by pseudo-second-order kinetic model, suggesting that chemisorption was main rate-controlling step. The Langmuir adsorption model provided much higher correlation coefficient than that of Freundlich adsorption model, indicating that the adsorption behavior is monolayer adsorption on the surface of the magnetic adsorbents. The above results have demonstrated that chitosan-based magnetic adsorbent CMC@Fe₃O₄ is suitable for the removal of inorganic arsenic in water.     

Adsorption behavior of three-dimensional magnetic hollow porous Ni-ferrites microsphere for dyes removal

In this study, the three-dimensional magnetic hollow porous Ni-ferrites (3D-MHP-NiFe₂O₄) microsphere has been synthesized. As-prepared 3D-MHP-NiFe₂O₄ exhibits superior adsorption capacities for brilliant green (BG) (147.93?mg?g^?1) and acid carmoisine (AC) (44.07?mg?g^?1). Compared with NiFe₂O₄ nanoparticles (NiFe₂O₄-NPs), the enhancement has been ascribed to relatively high specific surface area and unique hollow porous structure, which are favorable for transfer of adsorbates. The Langmuir isotherm model conforms well to the experimental data. The adsorption process obeys the pseudo-second-order kinetic model. The overall rate process has been mainly controlled by intraparticle diffusion. In addition, 3D-MHP-NiFe₂O₄ exhibits a high stability and good reusability.     

The Adsorption Effect of Quaternized Chitosan Derivatives on Bile Acid

Chitosan, which is easily derived from chitin by N-deacetylation. It is well known that hypercholesterolemia has been identified as a major risk factor in the development of atherosclerosis and its clinical sequelae like coronary heart disease and myocard…     

Mixed phase Fe2O3/Mn3O4 magnetic nanocomposite for enhanced adsorption of methyl orange dye: Neural network modeling and response surface methodology optimization

In this research, a novel magnetic mesoporous adsorbent with mixed phase of Fe₂O₃/Mn₃O₄ nanocomposite was prepared by a facile precipitating method and characterized extensively. The prepared nanocomposite was used as adsorbent for toxic methyl orange (MO) dye removal from aqua matrix considering its high surface area (178.27 m²/g) with high saturation magnetization (23.07 emu/g). Maximum dye adsorption occurs at solution pH 2.0 and the electrostatic attraction between anionic form of MO dye molecules and the positively charged nanocomposite surface is the main driving force behind this adsorption. Response surface methodology (RSM) was used for optimizing the process variables and maximum MO removal of 97.67% is obtained at optimum experimental condition with contact time, adsorbent dose and initial MO dye concentration of 45 min, 0.87 g/l and 116 mg/l, respectively. Artificial neural network (ANN) model with optimum topology of 3–5–1 was developed for predicting the MO removal (%), which has shown higher predictive ability than RSM model. Maximum adsorption capacity of this nanocomposite was found to be 322.58 mg/g from Langmuir isotherm model. Kinetic studies reveal the applicability of second‐order kinetic model with contribution of intra‐particle diffusion in this process.     

谷胱甘肽磁性分子印迹聚合物的制备及吸附性能研究

采用表面分子印迹技术,以谷胱甘肽（GSH）为模板分子,N-乙烯基吡咯烷酮（NVP）和丙烯酰胺（AM）为功能单体,N,N’-亚甲基双丙烯酰胺（MBA）为交联剂,γ-（甲基丙烯酰氧）丙基三甲氧基硅烷（KH570）改性的Fe₃O₄纳米颗粒为磁性载体,制备了对GSH有特异识别性的磁性分子印迹聚合物（GSH-MMIPs）. 利用X射线衍射仪（XRD）、透射电子显微镜（TEM）、红外光谱（FT-IR）和振动样品磁强计（VSM）对聚合物进行了表征,结果表明磁性载体表面成功地包覆了分子印迹聚合物薄层. 静态吸附平衡实验和Scatchard分析结果表明,GSH-MMIPs中存在两类不同的结合位点,平衡解离常数分别为8.786×10^-4 mol/L和5.424×10^-3 mol/L,最大吸附量分别为49.195 mg/g和155.003 mg/g. 与化学组成相同的磁性非印迹聚合物（GSH-MNIPs）相比,GSH-MMIPs对谷胱甘肽有较高的选择吸附性能.     

乳酸直接聚合的热力学、动力学研究

以乳酸单体为原料，在无催化剂存在和常压下直接缩聚合成聚乳酸，并研究了乳酸直接聚合的动力学，结合其热力学的分析，指出提高真空度脱除水分、控制合适的温度、选择合适的催化剂是获得高分子量聚乳酸的关键，为乳酸地接聚合工艺提供了理论参考。     

Adsorption equilibria of CO/H2 with a magnetic suspension balance: Purely gravimetric measurement

Adsorption equilibria of pure gases and binary gas mixtures can be measured with a new magnetic suspension balance. For this measurement no additional concentration measurement is required, neither for the gas phase nor for the adsorbed phase. The new instrument allows gravimetric adsorption measurements in a wide range of pressure (UHV...50 MPa) and temperature (210 K...570 K) to be performed. The experimental procedure and the instrument set up is fairly easy and can be compared to pure gas adsorption experiments. The new instrument and experimental procedure have been tested by performing coadsorption measurements with CO/H₂ mixtures on a commercial 5A zeolite.This revised version was published online in November 2005 with corrections to the Cover Date.