超声法制备磁性分子筛及其性能研究

在制备4A分子筛的基础上,引入四氧化三铁颗粒,辅助超声波,制备磁性分子筛,用于吸附去除Pb⁽²⁺⁾。结果表明,在超声波功率100 W的条件下,晶化时间6 h,晶化温度80℃,加入导向剂制备的磁性分子筛效果良好;引入的四氧化三铁没有破坏4A分子筛的晶体结构,但对结晶度有所影响。在铅离子初始浓度200 mg/L,吸附剂加入量5.0 g/L,溶液的pH值5.0,吸附时间15 min的条件下,对铅离子的去除率达98.2%,完全符合国标废水排放标准。     

磁性瓜子壳基活性炭的制备及其吸附研究

以瓜子壳为原料,磷酸为活化剂,通过微波法制备出具有高吸附效率的活性炭,与四氧化三铁结合成磁性活性炭粒子,研究活化温度、磷酸浓度、浸渍比、微波时间对活性炭吸附性能的影响,通过XRD、红外光谱对其外貌与官能团进行分析,通过吸附等温线、吸附动力学探讨了其机理。结果表明,最佳制备活性炭的工艺条件为:活化温度120℃,浸渍比4 g/15 m L,磷酸浓度20%,微波时间25 min,测得其碘吸附值为887. 349 mg/g,亚甲基蓝吸附量70 mg/g,磁性活性炭最佳碳/四氧化三铁为60%。红外谱图显示四氧化三铁与活性炭之间通过油酸相结合,有大量的羧酸基团。吸附等温线与吸附动力学表明,磁性活性炭粒子为均匀单层化学吸附。     

超声法制备磁性分子筛及其性能研究

在制备4A分子筛的基础上,引入四氧化三铁颗粒,辅助超声波,制备磁性分子筛,用于吸附去除Pb~(2+)。结果表明,在超声波功率100 W的条件下,晶化时间6 h,晶化温度80℃,加入导向剂制备的磁性分子筛效果良好;引入的四氧化三铁没有破坏4A分子筛的晶体结构,但对结晶度有所影响。在铅离子初始浓度200 mg/L,吸附剂加入量5.0 g/L,溶液的pH值5.0,吸附时间15 min的条件下,对铅离子的去除率达98.2%,完全符合国标废水排放标准。     

磁性瓜子壳基活性炭的制备及其吸附研究

以瓜子壳为原料,磷酸为活化剂,通过微波法制备出具有高吸附效率的活性炭,与四氧化三铁结合成磁性活性炭粒子,研究活化温度、磷酸浓度、浸渍比、微波时间对活性炭吸附性能的影响,通过XRD、红外光谱对其外貌与官能团进行分析,通过吸附等温线、吸附动力学探讨了其机理。结果表明,最佳制备活性炭的工艺条件为:活化温度120℃,浸渍比4 g/15 m L,磷酸浓度20%,微波时间25 min,测得其碘吸附值为887. 349 mg/g,亚甲基蓝吸附量70 mg/g,磁性活性炭最佳碳/四氧化三铁为60%。红外谱图显示四氧化三铁与活性炭之间通过油酸相结合,有大量的羧酸基团。吸附等温线与吸附动力学表明,磁性活性炭粒子为均匀单层化学吸附。     

铝土矿除氟吸附剂制备及其性能研究

以天然铝土矿物为原料,经高温煅烧活化制备高效除氟吸附剂。XRD图谱显示,该除氟剂主要成分为水铝石脱水生成的氧化铝。采用响应曲面法,对煅烧温度和煅烧时间与除氟剂吸附容量的关系曲线进行二次多项式拟合,结果表明煅烧温度对除氟剂吸附氟离子容量的影响程度高于煅烧时间,而两者的交互作用并不明显。在煅烧温度为840.8℃,煅烧时间为316.2min的最优制备条件下,其吸附容量约达1.7mg/g,是一种高效低廉的除氟吸附剂。     

聚苯胺/四氧化三铁/氧化石墨烯核壳纳米复合材料的制备及其吸附性能的研究

采用氧化法在常温下合成聚苯胺/四氧化三铁/氧化石墨烯核壳纳米复合材料,并作为吸附剂吸附Cu2+离子。用XRD和FT-IR进行表征。研究了不同吸附时间、p H和循环使用次数等对复合物吸附容量的影响,在25℃、溶液p H为4.8时最大吸附能力为43.2 mg/g。该复合材料对Cu2+离子吸附过程符合准二级动力学模型,表明吸附过程涉及吸附物与污染物之间的物理和化学相互作用。     

制备条件对掺镁羟基磷灰石结构及除氟性能的影响

为了提高羟基磷灰石(HAP)滤料的除氟能力,以磷酸、四水硝酸钙和六水硝酸镁为原料,采用化学沉淀法制备一种Mg掺杂羟基磷灰石(Mg-HAP)除氟滤料,研究了制备条件对滤料除氟性能的影响,探究了Mg-HAP滤料的结构与除氟性能之间的关系。结果表明:掺镁量和陈化时间主要影响晶体结构;钙、镁与磷的摩尔比和反应温度主要影响Mg-HAP的纯度;在滤料晶体结构相对保持完整时,滤料的羟基含量越多,滤料的除氟容量越高。在n(Mg)/n(Ca+Mg)为0.10,n(Ca+Mg)/n(P)为1.50,反应温度30℃,搅拌1 h,90℃陈化60 min的优化制备工艺条件下,制备的Mg-HAP滤料样品,Mg在HAP的内部分布均匀;Mg取代羟基磷灰石晶格中的少部分Ca,导致晶面结构发生畸变,晶格缺陷增加,表面吸附能力增强;同时滤料的羟基含量提高,滤料的除氟容量提高。与HAP相比,Mg-HAP除氟容量提高了近4倍。     

羟基磷灰石去除水中氟离子的效能研究

羟基磷灰石(HAP)是一种新型的氟离子吸附剂。以模拟含氟水样为处理对象,采用静态吸附实验研究了温度、p H值、吸附时间等因素对HAP除氟性能的影响。探讨了HAP吸附剂的等温吸附过程。结果表明:HAP的最大吸附量为5.32mg/g;50min之内吸附速率较快,在60min时吸附过程趋于平衡;酸性环境下吸附效果较好;升高温度有利于吸附的进行且吸附过程符合Langmuir模型。该研究可为HAP工业应用提供可靠的理论基础和科学依据。     

双甘膦修饰磁性四氧化三铁纳米微球吸附DNA的研究

用双甘膦(PMIDA)修饰磁性四氧化三铁纳米微球(MNP)并负载Zn2+制得了PMIDA-Zn2+修饰磁性微球吸附剂。考察了吸附溶液的pH值、离子强度、吸附时间、吸附温度等因素对DNA吸附的影响。结果表明,当吸附剂用量为10mg、pH值为5.0、离子强度(NaCl浓度)为2.0mol.L-1、吸附时间为20min、吸附温度为35℃时,吸附率可达80%,吸附容量为21mg.g-1。被吸附的DNA用3.5%的氨水能完全洗脱。将PMIDA-Zn2+修饰磁性微球用于玉米DNA的提取,所得DNA纯度较高,效果令人满意。     

石墨烯/Fe_3O_4复合物的制备及其对镁离子的吸附

先以膨胀石墨为原料,通过改进的Hummers法制备得到氧化石墨烯,再以硫酸亚铁、三氯化铁和制备得到的氧化石墨烯为原料,通过水浴加热的方法制备得到氧化石墨烯/四氧化三铁复合物。最后,以镁离子为吸附对象,研究工艺条件对氧化石墨烯/四氧化三铁复合物吸附率的影响。研究结果表明:吸附时间为6 min、吸附剂用量为10 mg和吸附温度为25℃时,制备得到的复合物对给定条件下的镁离子具有较好的吸附率。     

Effect of cation doping on the structure of hydroxyapatite and the mechanism of defluoridation

The structure of three cation-doped hydroxyapatite filter materials with different cation radii and valence states, aluminum-doped hydroxyapatite (Al-HA), magnesium-doped hydroxyapatite (Mg-HA) and lanthanum-doped hydroxyapatite (La-HA), were studied to explore the performance and possible mechanism of defluoridation by means of Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM)/Energy-dispersive X-ray spectroscopy (EDS), BET and Zeta potential analysis. The results demonstrated that cation doping with different radii could weaken lattice structure of hydroxyapatite, increase content of hydroxyl group and improve exchange ability with fluoride ions. However, the decisive factor affecting the capacity of fluoride removal was valence state of doped ion, because defluoridation capacity of Al-HA and La-HA with trivalent cations were larger than Mg-HA with bivalent cation. In addition, other studies related to the process of defluorination were carried out. The mechanism of defluoridation mainly included physical adsorption and chemical adsorption. First, F^- was deposited on the surface of the filter material by physical adsorption. After F^- diffused into the voids of the filter interval, and underwent ion exchange and complexation with -OH functional group in the lattice. Cation-doped hydroxyapatite structure and mechanism of fluoride removal were of great significance in the field of environmental governance.     

磁性橡胶的制备与性能研究

以聚乙二醇(PEG)6000表面改性的四氧化三铁为磁性填料制备改性四氧化三铁/NR/EPDM磁性橡胶,并对其微观结构、耐老化性能、耐酸碱性能、耐油性能和低温脆性进行研究.结果表明:以NR/EPDM并用胶为基体制备的磁性橡胶耐热老化性能、耐臭氧老化性能、耐酸碱性能和耐油性能均高于以NR为基体的磁性橡胶;基体橡胶种类对磁性橡胶的低温脆性影响不大.     

Defluoridation of drinking water using chemically modified bentonite clay

Adsorption potential of metal oxide (lanthanum, magnesium and manganese) incorporated bentonite clay was investigated for defluoridation of drinking water using batch equilibrium experiments to gain insight of adsorption behavior, kinetics and mechanisms of adsorption of fluoride ion. The effect of various physico-chemical parameters such as pH, adsorbent dose, initial fluoride concentration and the presence of interfering co-ions on adsorption of fluoride has been investigated. The 10%La-bentonite shows higher fluoride uptake capacity for defluoridation of drinking water as compared to Mg-bentonite, Mn-bentonite and bare bentonite clay. The uptake of fluoride in acidic pH was higher as compared to alkaline pH. The equilibrium adsorption data fitted reasonably well in both Langmuir and Freundlich isotherm models. It was also observed that in the presence of certain co-existing ions can have positive effect on removal of fluoride, while carbonate and bicarbonate anions show deleterious effect. The rate of adsorption was reasonably rapid and maximum fluoride uptake was attained within 30 min. The modified adsorbent material shows better fluoride removal properties for actual field water, which could be due to the positive effect of other co-ions present in the field water.     

Defluoridation of Water by Graphene Oxide Supported Needle-Like Complex Adsorbents

The dicarboxylic acids like oxalic acid, malonic acid and succinic acid mediated graphene oxide–zirconium needle like complexes were synthesized and used to remove fluoride from simulated fluoride contaminated water. The adsorption of fluoride by dicarboxylic acids mediated graphene oxide–zirconium complexes were by both electrostatic interaction at acidic pH and ion-exchange mechanism at neutral pH. The maximum defluoridation capacity observed was 9.70 mg/g at the minimum contact time of 18 min at room temperature. Various batch equilibrium parameters like pH studies, contact time, common ion interference and temperature studies were optimized. The synthesized graphene oxide and graphene oxide supported complexes were characterized using UV–vis, FTIR, XRD and SEM with EDAX analysis to establish the mechanism of fluoride adsorption. The removal of fluoride was described by the pseudo-second-order reaction kinetics, Freundlich isotherm model and thermodynamic studies which indicates the nature of adsorption was endothermic and spontaneous. Regeneration studies depict that the dicarboxylic acid mediated graphene oxide–zirconium complex can be used as an effective adsorbent for the removal of fluoride ions from wastewater. Also, the field applicability of the material has been verified with field samples collected from nearby fluoride endemic villages.     

磁化Fe3O4吸附溶液中铬（VI）的研究

不同磁场强度下，Ｆｅ３Ｏ４磁性介质对含铬（ＶＩ）溶液的静态吸附实验结果表明：磁化的Ｆｅ３Ｏ４对铬（ＶＩ）的吸附能力比不磁化时强，磁化的Ｆｅ３Ｏ４的吸附平衡关系式可用同Ｌａｎｇｍｕｉｒ等温式类似的等温方程描述。磁场强度越大，吸附等温方程与实验值的相关性越好，磁性Ｆｅ３Ｏ４的吸附量随磁场强度增大而增大，它们之间的函数关系可用类似于Ｆｒｅｕｎｄｌｉｃｈ吸附数学模型描述。     

Preparation and characterization of red mud sintered porous materials for water defluoridation

This research was undertaken to characterize a porous material prepared from red mud and to investigate the capacity of zirconium hydroxide-modified red mud porous materials (Zr-modified RMPMs) for the removal of fluoride from aqueous solutions. An organic foam template was used for the preparation. After sintering, the RMPM had a porosity up to 80 % with the pore size controlled between 50 and 100 μm. Batch experiments were performed to study the defluoridation of water using Zr-modified RMPM under various experimental conditions. Kinetic data revealed that the equilibrium for fluoride removal was achieved within 60 min. The fluoride sorption process was well fitted to the pseudo-second-order rate kinetics and pore diffusion models. The optimum fluoride removal was observed between pH range 3 and 4 and the adsorption capacity for fluoride by Zr-modified RMPM was 0.6 mg/g. Results from this study demonstrated potential use of Zr-modified RMPM in defluoridation of drinking water.     

Adsorption capacity of bone char for removing fluoride from water solution. Role of hydroxyapatite content,adsorption mechanism and competing anions

The adsorption of fluoride from water on bone char (BC) was investigated in this work, and the fluoride adsorption capacity of BC was compared to that of hydroxyapatite (HAP). The adsorption capacity of BC and HAP drastically increased while decreasing the pH from 7.0 to 5.0. Furthermore, the fluoride adsorption on BC was due to its HAP content and was not considerably affected by the presence of the anions Cl⁻, HCO₃⁻, CO₃²⁻, SO₄²⁻, NO₃⁻ and NO₂⁻. The mechanism of fluoride adsorption on BC was attributed to electrostatic interactions between surface charge of BC and fluoride ions in solution.     

Preparation and property of porous hydroxyapatite as an inorganic dispersant used in suspension polymerization

The porous hydroxyapatite (HAP) for suspension polymerization dispersant was prepared using calcium carbonate and phosphoric acid as raw materials. The samples were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and BET nitrogen adsorption. The results show that the prepared HAP has a porous structure, low particle density, large specific surface area, uniform particle size and does not agglomerate easily between the particles. The preparation conditions for the HAP were optimized as follows: solid content of calcium carbonate aqueous suspension 90 g/L, concentration of phosphoric acid 1.0 mol/L, reaction/aging temperature 50°C, and aging time 3 h. The HAP prepared under optimal preparation conditions has 106.8 m²·g^-1 of specific surface area, which is about 1.5–1.8 times as much as that of Japanese HAP or commercial HAP. Its application result in the suspension polymerization of styrene show that the porous HAP dispersant has high surface activity, excellent suspension dispersibility and stability and can markedly improve the quality of polystyrene beads.     

Adsorption of fluoride from aqueous solution by magnesia‐amended silicon dioxide granules

BACKGROUND: A new kind of adsorbent, magnesia‐amended silicon dioxide granules (MAS), has been prepared by wet impregnation of silicon dioxide with magnesium chloride solution. The physicochemical properties were characterized using X‐ray diffraction (XRD), Fourier transform infrared (FT‐IR) and Brunauer, Emmett, Teller (BET) studies. The porous structure and high surface area of these granules make them suitable for sorption. The aim of this study was to show the possibility of defluoridation of water using MAS and to demonstrate the advantage of its use compared with silicon dioxide. RESULTS: XRD and FT‐IR analysis showed that amorphous magnesia was loaded on silicon dioxide after treating with magnesium chloride solution and calcining at 500 °C. Batch sorption experiments indicated that MAS is more effective than silicon dioxide for fluoride adsorption. The sorption capacities of MAS decreased as the solution pH rose. At pH 3, the maximum defluoridation capacity of MAS was 12.6 mg g^?1. The adsorption process fitted the Dubinin–Radushkevich isotherm and kinetic studies revealed that the adsorption followed second‐order rate kinetics. CONCLUSION: The results indicate that it is feasible to modify both the physical and chemical properties of silicon dioxide with magnesia so that it can be used as a potential adsorbent to adsorb fluoride from aqueous solution. Copyright © 2009 Society of Chemical Industry     

超声辅助合成磁性四氧化三铁/氧化石墨烯复合物及其在染料去除中的应用（英文）

A simple ultrasound-assisted co-precipitation method was developed to prepare ferroferric oxide/graphene oxide magnetic nanoparticles (Fe3O4/GO MNPs). The hysteresis loop of Fe3O4/GO MNPs demonstrated that the sample was typical of superparamagnetic material. The samples were characterized by transmission electron microscope, and it is found that the particles are of small size. The Fe3O4/GO MNPs were further used as an adsorbent to remove Rhodamine B. The effects of initial pH of the solution, the dosage of adsorbent, temperature, contact time and the presence of interfering dyes on adsorption performance were investigated as well. The adsorption equilibrium and kinetics data were fitted well with the Freundlich isotherm and the pseudo-second-order kinetic model respectively. The adsorption process followed intra-particle diffusion model with more than one process affecting the adsorption of Rhodamine B. And the adsorption process was endothermic in nature. Furthermore, the magnetic composite with a high adsorption capacity of Rhodamine B could be effectively and simply separated using an external magnetic field. And the used particles could be regenerated and recycled easily. The magnetic composite could find potential applications for the removal of dye pollutants.