双层SiO2包覆Fe3O4复合材料的制备及其染料吸附性能

采用改进的Stober法合成了多孔结构的双层SiO₂包覆Fe₃O₄复合材料,利用TEM、XRD、VSM和氮吸附-脱附实验对其结构与性能进行分析,进而研究其对染料的吸附性能。研究结果表明,双层SiO₂包覆Fe₃O₄复合材料的比表面积和磁饱和强度分别为308 m²·g^-1和45.5 emu·g^-1;当罗丹明B的初始浓度从25 mg·L^-1提高到250 mg·L^-1时,复合材料对其饱和吸附量从24.0 mg·g^-1增大到112.4 mg·g^-1,而亚甲基蓝的初始浓度从25 mg·L^-1提高到500 mg·L^-1时,对其饱和吸附量从22.0 mg·g^-1增大到235.1 mg·g^-1;随着溶液pH值增大,复合材料对罗丹明B的饱和吸附量增加,而对亚甲基蓝的饱和吸附量变化不明显;温度在20~40 ℃范围内复合材料的吸附量较大。     

双层SiO2包覆Fe3O4复合材料的制备及其染料吸附性能

采用改进的Stober法合成了多孔结构的双层SiO₂包覆Fe₃O₄复合材料,利用TEM、XRD、VSM和氮吸附-脱附实验对其结构与性能进行分析,进而研究其对染料的吸附性能。研究结果表明,双层SiO₂包覆Fe₃O₄复合材料的比表面积和磁饱和强度分别为308 m²·g^-1和45.5 emu·g^-1;当罗丹明B的初始浓度从25 mg·L^-1提高到250 mg·L^-1时,复合材料对其饱和吸附量从24.0 mg·g^-1增大到112.4 mg·g^-1,而亚甲基蓝的初始浓度从25 mg·L^-1提高到500 mg·L^-1时,对其饱和吸附量从22.0 mg·g^-1增大到235.1 mg·g^-1;随着溶液pH值增大,复合材料对罗丹明B的饱和吸附量增加,而对亚甲基蓝的饱和吸附量变化不明显;温度在20~40 ℃范围内复合材料的吸附量较大。     

D301树脂吸附铼(Ⅶ)的研究

本文研究了D301树脂对铼(Ⅶ)的吸附性能,结果表明在T=298 K,pH=2.7的HAc-NaAc缓冲溶液中静态饱和吸附容量为715 mg·g^-1;0.5~5.0 mol·L^-1 HCl溶液可以不同程度地解吸树脂上的铼,其中4.0 mol·L^-1 HCl作为解吸剂时,一次解吸率可达100%。反应开始阶段的表观吸附速率常数k_{298 K}=7.2×10^-5 s^-1;等温吸附服从Freundlich经验式;吸附反应的ΔH=-4.4 kJ·mol^-1;吸附物中树脂功能基与Re(Ⅶ)的物质的量比约为1∶1。并用化学法和红外光谱探讨了吸附机理。     

铝改性赤泥吸附剂的制备及其除氟效能的研究

以铝工业废矿渣为原材料,通过铝盐改性及焙烧活化处理,制备了水中除氟吸附剂。研究考察了吸附剂吸附氟能力、反应时间、pH值以及投加量对吸附效果的影响。结果表明,铝改性赤泥吸附剂具有较好的除氟效果,未焙烧铝改性赤泥吸附剂及经过200 ℃焙烧活化赤泥吸附剂的饱和吸附量分别达到68.07和91.28 mg·g^-1,远高于原状赤泥的饱和吸附量13.46 mg·g^-1。经吸附后出水氟含量低于1 mg·L^-1的国家饮用水标准。吸附规律符合Langmuir等温方程,溶液pH值显著影响除氟效果,在溶液pH值为7~8时达到最佳去除效果。     

钴镍双金属氢氧化物/石墨烯电控分离膜排异性回收废水中低浓度磷酸盐

采用滴涂结合电化学沉积两步法制备了一种具有优良电活性的三维花状钴镍双金属氢氧化物/石墨烯(CoNi-LDH/G)杂化膜,用于电控离子交换过程(electrically switched ion exchange,ESIX)吸附水溶液中低浓度的磷酸根(PO₄^3-)离子。结合 X射线衍射(XRD)、X射线光电子能谱(XPS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等对CoNi-LDH/G杂化膜进行形貌、组成及结构表征。采用电化学方法考察了该杂化膜在不同吸附电压、不同初始浓度、共存离子及不同pH值条件下对PO₄^3-吸附性能的影响。实验结果表明：通过调节氧化还原电位,即使在低浓度下,杂化膜对 PO₄^3-也具有良好的吸附性能,且可以在较宽的pH 值(4~10)范围内使用,同时受共存离子及其浓度变化影响甚小。此外,G 对 PO₄^3-的吸附容量为 1.10 mg·g^-1,CoNi-LDH 对PO₄^3-的吸附容量为11.74 mg·g^-1,二者吸附容量之和小于CoNi-LDH/G对PO₄^3-的吸附容量(16.25 mg·g^-1)。同时,结合O1s的XPS数据分析发现,CoNi-LDH/G杂化膜对PO₄^3-的吸附过程除了层间阴离子交换、PO₄^3-与层板金属离子配位的配体交换外,还存在G与CoNi-LDH之间的协同效应。     

磁性壳聚糖/Fe3O4/氧化石墨烯吸附剂的制备及其多染料吸附性能

为了提高壳聚糖的多染料吸附性能并使其便于固液分离,采用共沉淀法制备了壳聚糖、磁铁矿纳米颗粒、氧化石墨烯复合磁性吸附剂(CS/Fe₃O₄/GO)。系统的结构表征显示,CS包覆的Fe₃O₄磁性纳米颗粒均匀地分布在GO的表面。CS/Fe₃O₄/GO具有高达42.5 emu·g^-1的室温铁磁性,因此可在外加磁场中实现高效固液分离。研究表明,CS/Fe₃O₄/GO对亚甲基蓝(MB)、甲基橙(MO)和刚果红(CR)等多种染料具有良好的吸附性能,溶液的pH、初始浓度和吸附时间对其多染料吸附性能具有显著影响。在最佳条件下,CS/Fe₃O₄/GO对MB、MO和CR的吸附量分别达到210.6、258.6和308.9 mg·g^-1。CS/Fe₃O₄/GO具有优异的循环利用性能,经5次循环后仍能保留90%以上的原始吸附量。采用吸附等温线和吸附动力学对CS/Fe₃O₄/GO的多染料吸附性能进行了拟合分析,并详细讨论了其吸附机理。     

纳米羟基磷灰石稳定悬浮体系的制备及其钴吸附性能

为改善纳米羟基磷灰石(HAP)作为重金属离子吸附剂的吸附性能,模拟了人体中聚合物诱导的类液体前驱体矿化过程,利用聚丙烯酸(PAA)作调控剂通过水热法制备出了稳定悬浮的纳米HAP体系,探究了PAA的COOH与Ca的物质的量之比(R)、反应 pH、水热温度对制备的纳米 HAP的影响。在优化出的合成条件(R=1、pH=9.00、180 ℃)下制备的纳米 HAP是由细小颗粒组成的梭形结构,能够在保持几十纳米粒径尺寸的同时稳定悬浮。继而探究了吸附时间、初始金属离子浓度、吸附环境的pH、悬浮性对纳米HAP的Co²⁺吸附性能的影响。吸附结果表明吸附动力学符合准二级动力学模型,吸附过程包括表面吸附与粒子内扩散。Freundlich、Langmuir模型线性方程拟合结果与实验结果均具有较高契合度,对应的Langmuir模型线性拟合最大吸附量为 229.358 mg·g^-1。对 Co²⁺去除率随吸附环境 pH(6.48~9.00)的升高而增大,主要吸附机制为表面配位反应。制备的纳米HAP悬浮液吸附量明显优于非悬浮的对照纳米HAP。     

银纳米颗粒掺杂的活性微孔炭球：一种高效吸附/催化去除刚果红的双功能材料

以载银纳米颗粒壳聚糖溶液为前驱体,联合喷雾干燥法、高温碳化法和KOH活化法制备出银纳米颗粒掺杂的活性微孔炭球(Ag/AMCSs)。基于一系列表征和性能研究发现,银纳米颗粒均匀分布于Ag/AMCSs结构中,Ag/AMCSs不仅表现出优异的染料吸附性能,而且可以有效催化NaBH₄还原刚果红(CR)的反应。此外,通过研究pH值、接触时间和染料初始浓度对Ag/AMCSs吸附性能的影响,发现Ag/AMCSs对CR的吸附过程符合准二级动力学模型和Langmuir模型,最大吸附量(q_e)可达445mg·g^-1。Ag/AMCSs催化NaBH₄还原CR,反应速率常数k可达0.311min^-1,5次循环利用后,染料催化转化率仍可高达95%。     

Cu2+和Cu+对原代培养的小鼠成骨细胞增殖、分化和钙化的影响

利用噻唑蓝(MTT)法、碱性磷酸酶(ALP)比活性测定、油红O染色和矿化结节染色及定量分析,研究了Cu²⁺和Cu⁺对原代培养的成骨细胞增殖、分化及钙化的影响。结果显示：Cu²⁺(1×10^-9~1×10^-6 mol·L^-1)促进成骨细胞增殖,随时间延长,促进作用变弱。Cu⁺(1×10^-7~1×10^-5 mol·L^-1)抑制成骨细胞增殖,随时间延长,浓度为1×10^-6 mol·L^-1的Cu⁺为促进作用,其余浓度则没有影响。对于成骨细胞分化,Cu²⁺和Cu⁺表现出相似的影响,浓度为1×10^-9和1×10^-6 mol·L^-1时均促进成骨细胞分化,而当浓度为1×10^-7和1×10^-5 mol·L^-1时,则抑制成骨细胞分化,随作用时间延长,大多数浓度均表现为促进作用。测试浓度下的Cu²⁺和Cu⁺均对成骨细胞向脂肪细胞的横向分化表现为促进效应。对矿化功能的影响,1×10^-5 mol·L^-1的Cu²⁺和Cu⁺表现出显著的抑制效应,但随浓度降低,抑制效应变弱。1×10^-7 mol·L^-1的Cu²⁺ 促进成骨细胞矿化结节的形成。结果提示：作用浓度、作用时间及铜离子的价态都是影响Cu²⁺和Cu⁺生物效应转变(从毒性到活性,从损伤到保护,从下调到上调)的关键因素。     

三维Cu-MOF对亚甲蓝的吸附和光催化降解及其机理

本文报道了[Cu₃(ppda)₃(tib)₂(H₂O)₄]·6H₂O (Cu-MOF)的合成、结构、吸附和光催化降解性能。在Cu-MOF中，1，4-苯二乙酸(H₂ppda)和1，3，5-三(1-咪唑基)苯(tib)配体交替连接Cu离子形成二维层，层与层之间通过trans-ppda^2-相互穿插形成稳定的三维结构。Cu-MOF对亚甲蓝(MB)的催化效率为97%，最高反应速率常数为0.019 7 min^-1。光催化降解机理：在光的激发下，催化剂表面的光生电子和空穴对发生分离，并与O₂、H₂O、H₂O₂反应生成活性物质，将染料降解为CO₂和H₂O。在MB溶液中加入NaCl (200 g·L^-1)后，Cu-MOF的吸附量有所提升(87.23 mg·g^-1)，准二级动力学模型和Langmuir等温线模型的实验数据拟合程度较好，该吸附的主要过程为单层化学吸附。     

Adsorption study for removal of Congo red anionic dye using organo-attapulgite

The organo-attapulgite was prepared using hexadecyltrimethylammonium bromide (HTMAB) with equation equivalent ratio of HTMAB to CEC of attapulgite added and then used as adsorbent for the removal of Congo red (CR) anionic dye from aqueous solution. Adsorbent characterizations were investigated using infrared spectroscopy and X-ray diffraction. The effects of contact time, temperature, pH and initial dye concentration on organo-attapulgite adsorption for CR were investigated. The results show that the amount adsorbed of CR on the organo-attapulgite increase with increasing dye concentration, temperature, and by decreasing pH. The adsorption kinetics was studied with the pseudo-first-order, pseudo-second-order and intraparticle diffusion models, and the rate constants were evaluated. It was found that the adsorption mechanisms in the dye/organo-attapulgite system follow pseudo-second-order kinetics with a significant contribution of film diffusion. Equilibrium data fitted perfectly with Langmuir isotherm model compared to Freundlich isotherm model, and the maximum adsorption capacity was 189.39 mg g⁻¹ for the adsorbent. Kinetic and desorption studies both suggest that chemisorption should be the major mode of CR removal by the organo-attapulgite. The results indicate that HTMAB-modified attapulgite could be employed as low-cost material for the removal of Congo red anionic dye from wastewater.     

Quartzite an efficient adsorbent for the removal of anionic and cationic dyes from aqueous solutions

Quartzite obtained from local source was investigated for the removal of anionic dye congo red (CR) and cationic dye malachite green (MG) as an adsorbent from aqueous solution in batch experiment. The adsorption process was studied as a function of dye concentration, contact time, pH and temperature. Adsorption process was described well by Langmuir and Freundlich isotherms. The adsorption capacity remained 666.7 mg/g for CR dye and 348.125 mg/g for MG dye. Data was analyzed thermodynamically, ΔH⁰ and ΔG⁰ values proved that adsorption of CR and MG is an endothermic and spontaneous process. Adsorption data fitted best in the pseudo-first order kinetic model. The adsorption data proved that quartzite exhibits the best adsorption capacity and can be utilized for the removal of anionic and cationic dyes.     

Characterization and Mechanism Elucidation of Dye Adsorption Using Cuprous Selenide Nanoparticles from Aqueous Solutions

The removal of cationic dyes, methylene blue(MB) and rhodamine B(RB), and anionic dyes, methyl or-ange(MO) and eosin Y(EY), from aqueous solutions by adsorption using Cu₂Se nanoparticles(Cu₂SeNPs) was studied. The effects of the initial pH values, adsorbent doses, contact time, initial dye concentrations, salt concentrations, and operation temperatures on the adsorption capacities were investigated. The adsorption process was better fitted the Langmuir equation and pseudo-second-order kinetic model, and was spontaneous and endothermic as well. The adsorption mechanism was probably based on the electrostatic interactions and π-π interactions between Cu₂SeNPs and dyes. For an adsorbent of 0.4 g/L of Cu₂SeNPs, the adsorption capacities of 23.1(MB), 22.9(RB) and 23.9(EY) mg/g were achieved, respectively, with an initial dye concentration of 10 mg/g(pH=8 for MB and pH=4 for RB and EY) and a contact time of 120 min. The removal rate of MB was still 70.4% for Cu₂SeNPs being reused in the 5th cycle. Furthermore, the recycled Cu₂SeNPs produced from selenium nanoparticles adsorbing copper were also an effective adsorbent for the removal of dyes. Cu₂SeNPs showed great potential as a new adsorbent for dyes removal due to its good stability, functionalization and reusability.     

Adsorption of Hazardous Azorhodanine Dye from an Aqueous Solution Using Rice Straw Fly Ash

The potential of using rice straw fly ash (RSFA) as low-cost adsorbents for the removal of hazardous azorhodanine (AR) dye from aqueous solution was investigated. The effects of different variables in the batch method as a function of solution pH, contact time, concentration of adsorbate, adsorbent dosage, and temperature were investigated, and optimal experimental conditions were ascertained: 0.05 g for initial dye concentration of 20–100 mg/L at pH 2. The experimental equilibrium data were tested by the isotherm models, namely the Langmuir and Freundlich adsorption and the isotherm constants were determined. The kinetic models, pseudo-first-order and pseudo-second-order, were employed to analyze the kinetic data. The activation energy of adsorption was also evaluated and found to be +10.89 kJ.mol^?1, indicating that the adsorption is physisorption. Various thermodynamic parameters, such as Gibbs free energy, entropy, and enthalpy of the ongoing adsorption process, have been calculated and found to be spontaneous and exothermic, respectively.     

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.     

Adsorption studies on the removal of Vertigo Blue 49 and Orange DNA13 from aqueous solutions using carbon slurry developed from a waste material

Waste material (carbon slurry), from fuel oil-based generators, was used as adsorbent for the removal of two reactive dyes from synthetic textile wastewater. The study describes the results of batch experiments on removal of Vertigo Blue 49 and Orange DNA13 from synthetic textile wastewater onto activated carbon slurry. The utility of waste material in adsorbing reactive dyes from aqueous solutions has been studied as a function of contact time, temperature, pH, and initial dye concentrations by batch experiments. pH 7.0 was found suitable for maximum removal of Vertigo Blue 49 and Orange DNA13. Dye adsorption capacities of carbon slurry for the Vertigo Blue 49 and the Orange DNA13 were 11.57 and 4.54 mg g(-1) adsorbent, respectively. The adsorption isotherms for both dyes were better described by the Langmuir isotherm. Thermodynamic treatment of adsorption data showed an exothermic nature of adsorption with both dyes. The dye uptake process was found to follow second-order kinetics.     

Fast and highly efficient removal of anionic organic dyes with a new Cu modified nanoclinoptilolite

Adsorption of anionic dyes onto most of zeolites with net negative charge may be restricted. In this article, a natural nanoclinoptilolite was modified with Cu and the obtained nanomaterial was used as an effective adsorbent for removal of methyl red as an anionic model azo dye up to 90% in 20 min.This new adsorbent was characterized utilizing X-ray diffraction, Fourier transform infrared spectroscopy, field emission scanning electron microscopy and energy-dispersive X-ray spectroscopy. Also, effects of methyl red concentration, mass of sorbent and pH on the removal percent were examined. Moreover, the adsorption mechanism was investigated by plotting the Langmuir and Freundlich adsorption isotherms. The results showed that the data can be fitted with both models. The most adsorption capacity obtained from Langmuir isotherm was about 200 mg/g. Moreover, the Cu modified nanoclinoptilolite was successfully employed for adsorption of another anionic dye, bromothymol blue. The results confirmed that this new adsorbent can be effectively applied for removing of anionic dyes from waste waters.     

Treatment of methyl orange by calcined layered double hydroxides in aqueous solution: adsorption property and kinetic studies

Adsorption of a weak acid dye, methyl orange (MO) by calcined layered double hydroxides (LDO) with Zn/Al molar ratio of 3:1 was investigated. In the light of so called "memory effect," LDO was found to recover their original layered structure in the presence of appropriate anions, after adsorption part of MO(-) and CO(2-)(3) (come from air) intercalated into the interlayer of LDH which had been supported by XRD and ICP. The results of adsorption experiments indicate that the maximum capacity of MO at equilibrium (Q(e)) and percentage of adsorption (eta%) with a fixed adsorbent dose of 0.5 g L(-1) were found to be 181.9 mg g(-1) and 90.95%, respectively, when MO concentration, temperature, pH and equilibrium time were 100 mg L(-1), 298 K, 6.0 and 120 min, respectively. The isotherms showed that the adsorption of MO by Zn/Al-LDO was both consistent with Langmuir and Freundlich equations. The adsorption process was spontaneous and endothermic in nature and followed pseudo-second-order kinetic model. The calculated value of E(a) was found to be 77.1 kJ mol(-1), which suggests that the process of adsorption of methyl orange is controlled by the rate of reaction rather than diffusion. The possible mechanism for MO adsorption has also been presumed. In addition, the competitive anions on adsorption and the regeneration of Zn/Al-LDO have also been investigated.     

Low-temperature synthesis of nanoparticle-assembled, transparent, and low-crystallized hydroxyapatite blocks

The mesoporous carbon CMK-3 adsorbent was prepared, characterized, and used for the removal of anionic methyl orange dye from aqueous solution. Adsorption experiments were carried out as batch studies at different contact time, pH, initial dye concentration, and salt concentration. The dye adsorption equilibrium was rapidly attained after 60 min of contact time. Removal of dye in acidic solutions was better than in basic solutions. The adsorption of dye increased with increasing initial dye concentration and salt concentration. The equilibrium data were analyzed by the Langmuir and Freundlich models, which revealed that Langmuir model was more suitable to describe the methyl orange adsorption than Freundlich model. Experimental data were analyzed using pseudo-first-order and pseudo-second-order kinetic models. It was found that kinetics followed a pseudo-second-order equation. Thermodynamic study showed that the adsorption was a spontaneous and exothermic process.     

荞麦皮生物吸附去除水中Cr(Ⅵ)的吸附特性和机理

农业废弃物荞麦皮作为生物吸附剂去除水中Cr(Ⅵ),研究了荞麦皮对Cr(Ⅵ)的去除动力学以及溶液pH、吸附剂用量和Cr(Ⅵ)初始浓度对去除效率的影响;通过FT-IR,XPS,SEM-EDX对荞麦皮表面组成和结构进行表征,探索荞麦皮去除Cr(Ⅵ)的机理.结果显示:荞麦皮对Cr(Ⅵ)有很高的去除效率.常温下5.0 g·L-1的荞麦皮在pH=2.0下对100 mg·L-1 Cr(Ⅵ)溶液的去除率可达99.87%.荞麦皮对Cr(Ⅵ)的去除率随溶液pH降低而升高,在pH=2.0时达到最大;随吸附剂用量增加而增大;随Cr(Ⅵ)初始浓度增加而减小.单位质量荞麦皮对Cr(Ⅵ)的去除量随吸附剂用量增加而减小;随Cr(Ⅵ)初始浓度增加而增加,最后趋于稳定.在20℃,pH=2.0,吸附用量为5.0 g·L-1时,荞麦皮对Cr(Ⅵ)的最大去除容量约为36.4 mg·g-1.荞麦皮吸附去除Cr(Ⅵ)的过程符合准二级吸附动力学.FT-IR,XPS和SEM-EDX分析结果表明:荞麦皮是一个多孔材料,表面存在羧基、氨基、羟基等活性基团;荞麦皮对Cr(Ⅵ)的去除是一个吸附-还原耦合的过程,包括Cr(Ⅵ)在荞麦皮表面上的静电吸附,以及此后的固相还原和对还原态的Cr(Ⅲ)再吸附;Cr(Ⅲ)的吸附主要是通过与荞麦皮表面的羧基、氨基的配位,以及与其中的阳离子发生离子交换作用实现的.