具有染料选择吸附性的衍生于沸石咪唑酯骨架-67的NiCo-层状双氢氧化物设计与合成（英文）

以沸石咪唑类金属有机骨架(ZIF-67)为模板合成了一种新型的中空吸附剂NiCo-LDH@ZIF-67,该吸附剂对甲基橙具有良好的选择吸附性以及可循环性。通过扫描电子显微镜(SEM)、透射电子显微镜(TEM)、X射线粉末衍射仪(XRD)、红外光谱、电子能谱和氮气吸附-脱附等手段对样品进行了表征。研究了溶液的pH值、甲基橙的初始浓度以及染料与吸附剂作用时间对NiCo-LDH@ZIF-67吸附性能的影响。结果表明,该吸附剂对甲基橙的吸附动力学符合准二级动力学模型,且吸附等温线符合朗缪尔方程。当pH值等于4,吸附时间15 min,吸附剂用量为2400 mg/L时,该吸附剂对甲基橙的最大吸附量可达1766 mg/g,高于之前文献报道的类似吸附剂。此外,NiCo-LDH@ZIF-67能从甲基橙和亚甲基蓝的混合溶液中选择性吸附甲基橙。     

聚苯胺/凹凸棒石负载纳米铁降解水溶液中甲基橙

以聚苯胺/凹凸棒石(PANI/ATP)为载体,采用液相还原法合成了负载型纳米零价铁(nZVI),用扫描电子显微镜(SEM)、透射电子显微镜(TEM)及X射线光电子能谱分析仪(XPS)等技术手段对纳米复合材料进行表征,考察了反应时间和pH值对甲基橙降解性能的影响,对降解过程进行了动力学分析,探讨了nZVI/PANI/ATP复合材料对甲基橙的降解机理。 结果表明,nZVI/PANI/ATP复合材料在较大pH值范围内能有效降解水中甲基橙并具有降解长效性,当催化剂用量1.0 g/L,降解体积50 mL,甲基橙的浓度20 mg/L,降解时间30 min时,复合材料对甲基橙的降解率达到95.8%以上,对甲基橙的降解过程符合准二级动力学模型。     

高分散纳米薄水铝石和纳米氧化铝的制备及其对甲基橙的吸附性能

以硝酸铝为铝源,尿素为沉淀剂,采用无模板水热法合成纳米薄水铝石(γ-AlO(OH))。在不同温度下煅烧后,得到氧化铝产物(γ-Al2O_3和θ-Al2O_3)。利用X射线衍射(XRD)、场发射扫描电子显微镜(FESEM)、透射电子显微镜(TEM)、傅里叶变换红外光谱(FTIR)、氮气吸附-脱附法和紫外-可见分光光度计(UV-Vis)对产物进行了表征分析。并且研究了产物对甲基橙(MO)的吸附性能,系统地考察了吸附时间、溶液的pH值、甲基橙浓度及循环使用对产物吸附性能的影响。此外,还对吸附过程进行了相关吸附理论研究。结果表明:与其他方法所制备的产物相比,通过该方法获得的产物的分散性更高,形态更均匀和完整。产物为高度分散的纳米捆扎状结构。γ-AlO(OH)对甲基橙的最大吸附量达1 492.5 mg·g~(-1)。另外,产物的吸附机制包含化学作用吸附机制和静电作用吸附机制等。3种产物对甲基橙的吸附均符合Langmuir单分子层吸附模型,吸附过程均符合二级动力学特征。     

新型功能介孔吸附剂NiNb_2O_6的合成及其吸附性能研究

通过柠檬酸溶胶-凝胶反应,合成了新型功能介孔NiNb2O6吸附剂,通过X-射线粉末衍射仪(XRD)、透射电镜(TEM)和比表面积及孔径分析(BET)对其结构进行表征。通过影响因素实验、吸附动力学实验和等温吸附实验,探讨了NiNb2O6吸附剂对水溶液中亚甲基蓝的吸附性能和机理。结果表明,NiNb2O6介孔吸附剂具有正交相晶体结构,平均粒径为30~200nm,比表面积为66.3m2/g。吸附剂用量、温度和pH值均对吸附行为有一定的影响;在35℃时,亚甲基蓝在吸附剂上吸附行为符合Langmuir方程,吸附动力学符合拟二级动力学方程,初始浓度为40mg/L,pH值为7.03时,0.2g介孔吸附剂NiNb2O6对亚甲基蓝的吸附量最大,吸附过程中液膜扩散为主要速率控制步骤。     

生物吸附剂菹草干粉对Cr(Ⅵ)的吸附性能

开发了高效去除重金属Cr(Ⅵ)污染的生物吸附剂,菹草(Potamogeton crispus)干粉吸附剂,通过单因素分析考察了吸附时间、吸附剂颗粒大小、溶液初始pH值、吸附剂用量、Cr(Ⅵ)初始浓度以及离子强度等对重金属离子Cr(Ⅵ)的吸附性能。 结果表明,对吸附效果影响显著的因素有Cr(Ⅵ)初始浓度、吸附剂颗粒大小、溶液初始pH值和离子强度;其吸附行为符合准二级动力学方程,相关系数为0.9998;菹草对Cr(Ⅵ)的吸附等温线符合Langmuir方程。     

用于染料吸附的改性沸石吸附剂:机理及功能表征

以十六烷基三甲基溴化铵(CTAB)改性沸石作为吸附剂,研究了其对水溶液中甲基橙(MO)的吸附行为。用红外光谱(FT-IR)和BET方法对沸石进行了表征。研究表明,CTAB改性沸石对MO的吸附符合Langmuir模型,在pH值为7、温度为298.15K、振荡速度为160r/min时,CTAB改性沸石对MO的最大吸附量为82mg/g。动态吸附实验表明,CTAB改性沸石对MO的吸附动力学可以用准二级动力学方程描述,说明它的吸附机理是一个物理与化学吸附过程。     

氧化铟改性聚丙烯酰胺复合材料吸附水中铅的研究

环境中铅污染将威胁到生命体安全,因此去除过量的铅显得尤为重要。采用一锅法制备了复合材料吸附剂氧化铟改性的聚丙烯酰胺,通过扫描电子显微镜、N_(2)吸附-脱附仪和热重分析仪对吸附剂进行了表征。结合火焰原子吸收光谱法,研究其对水中的铅吸附性能。优化了溶液pH值及振荡时间对铅吸附的影响,并运用动力学和热力学研究了复合材料对铅的吸附行为。实验结果表明:在初始浓度为10 mg/L,溶液pH值为6.0,振荡时间为100 min时,铅的最大吸附量为9.689 mg/g;吸附行为符合拟二级动力学方程和Freundlich方程;当T=293.15 K时,ΔG=-8.38 kJ/mol,ΔH=23.90 J/mol,证明了复合材料对铅的吸附是自发进行,并且是吸热过程;经过3次吸附—解吸实验,复合材料对铅的解吸率仍大于87%,说明吸附剂的再生性能良好。     

Fe3O4@HTlc的制备及其对甲基橙的吸附研究

采用液相非稳态共沉淀法制备了磁性镁铝类水滑石(Fe3O4@HTlc),采用透射电子显微镜、粉末X射线衍射仪、傅里叶变换红外光谱仪、振动样品磁强计、比表面分析仪、微电泳仪等对样品的形貌和结构进行了表征,并比较了 Fe3O4@HTlc和HTlc对甲基橙的吸附性能。结果表明,Fe3O4@HTlc为顺磁性、具有核-壳结构和较大比表面积、带有正电荷的近球状颗粒。甲基橙在Fe3O4@HTlc和HTlc上的吸附动力学曲线均符合准一级动力学方程;吸附等温线均符合Langmuir吸附等温式;298 K时Fe3O4@HTlc和HTlc对甲基橙的饱和吸附量分别为138.89和147.06 mg/g,但Fe3O4@HTlc对甲基橙有较强吸附推动力和较短的吸附平衡时间。二者对甲基橙的吸附量均随温度的升高和pH (5~11)的增加而降低。     

氧化石墨烯改性粘胶纤维复合材料的制备及对水中甲基橙的吸附性能研究

以粘胶纤维(VF)为原料，氢氧化钠为催化剂，氯乙酸钠为改性剂，对粘胶纤维进行羧甲基改性，制备了改性阴离子粘胶纤维(AVF)。以阴离子粘胶纤维为原料，聚乙烯亚胺为交联剂，氧化石墨烯(GO)为改性剂，采用高压反应釜在高温条件下制备了氧化石墨烯改性粘胶纤维复合材料(VF-g-GO),并通过IR、SEM、XPS对产品进行表征，证明VF-g-GO制备成功。三因素三水平正交实验结果表明：VF-g-GO的最佳合成条件是反应温度140℃、聚乙烯亚胺添加量3g、氧化石墨烯添加量0.25g。吸附实验结果表明：VF-g-GO对甲基橙的吸附量随溶液浓度的增加而增大，VF-g-GO在2.0×10^-4mol/L的甲基橙溶液中达到饱和吸附量87mg/g。同时VF-g-GO具有pH敏感性，经过pH=5盐酸溶液酸化处理的VF-g-GO对甲基橙的吸附量明显高于未经盐酸处理的VF-g-GO的吸附量。吸附动力学和吸附等温线实验表明：VF-g-GO对甲基橙的吸附符合准二级动力学方程，Freundlich吸附模型更能解释VF-g-GO对甲基橙的吸附作用。     

海藻酸钠固定化桔青霉微球对铀的吸附研究

以桔青霉(PC)作为对照,研究了铀溶液的pH值、吸附时间对海藻酸钠固定化微球(SAIPC)吸附性能的影响,吸附铀的最佳pH为6,7h基本达到吸附平衡。在308K,铀浓度为50μg/mL,pH值为6.0,SAIPC和PC分别在7h,5h达到吸附平衡,它们的吸附容量分别达256和116mg/g。对吸附动力学模型和吸附等温模型进行了分析,SAIPC对铀离子的吸附动力学模型较好地符合了准二级动力学方程,吸附等温线符合Freundlich和Langmuir吸附模型。结果表明:SAIPC是一种具有良好应用前景的,可望在工业中应用的生物吸附剂。     

三聚氰胺功能化多孔有机聚合物的合成及其对甲基橙的吸附性能

首先以对三联苯(TP)和对苯二甲酰氯(TC)为单体合成了酮基聚合物前体(TP-TC),而后基于席夫碱反应将三聚氰胺(MA)与之交联得到胺功能化的多孔有机聚合物TP-TC-MA。通过扫描电镜(SEM)、透射电镜(TEM)、傅里叶变换红外光谱(FT-IR)、X射线衍射(XRD)、氮气吸附-脱附(BET)以及零电荷点(pH_pzc)的测定等手段对合成的多孔有机聚合物进行表征。以染料废水中典型的阴离子染料甲基橙为研究对象,研究了TP-TC-MA对其吸附行为,并探讨了吸附机制。利用紫外-可见分光光度计(UV-Vis)得出目标污染物的紫外吸收光谱标准曲线,标准曲线拟合相关系数(R²)为0.999。结果表明,TP-TC-MA由于具有高比表面积(708.5 m²/g)和总孔体积(0.556 cm³/g)以及丰富的含氮基团,对阴离子染料甲基橙表现出优异的吸附性能。TP-TC-MA对水中甲基橙的吸附动力学符合准二级动力学方程,吸附平衡数据可以采用Langmuir等温吸附模型描述。经由Langmuir等温吸附模型计算得到的理论最大吸附容量为156.3 mg/g。选择性实验结果表明,TP-TC-MA对阴离子染料甲基橙具有更强的吸附作用,吸附作用机理可归结为静电相互作用、氢键和π-π相互作用等。在重复使用5次之后,TP-TC-MA对甲基橙仍保持90%以上的去除率,表明材料具有良好的稳定性和重复利用性,在染料废水处理中具有很好的应用前景。     

Thermodynamic study of Iron (III) removing by the synthesized α-Alumina powder and evaluating the corresponding adsorption isotherm models using Response Surface Method

In this study, α-Alumina as an adsorbent was initially synthesized by combustion method and characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), EDAX and Brunauer–Emmett–Teller (BET) techniques. Then the efficiency of the synthetized adsorbent for iron (III) removal was investigated and the effect of corresponding parameters such as adsorbent dose, contact time, initial concentration, temperature and solution pH on the adsorption capacity were examined and the optimums values of these parameters were concluded upon the surfaces response method. By using response surface methodology (RSM), the adsorption experimental design was performed and the statistical analysis showed that the quadratic model as well as the model terms were significant. In addition, the experimental results were examined with some suitable models, such as Langmuir, Freundlich isotherm models, where Freundlich model fitted better our experimental results. Finally, the thermodynamic behavior of the studied adsorption process was considered and the thermodynamic functions of the process were evaluated. The results showed that the Fe (III) ion adsorption onto the synthesized adsorbent is exothermic and spontaneous at the experimental conditions.     

Removal of Rhodamine B,a Cationic Dye From Aqueous Solution Using Poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) Nanotubes

Poly(cyclotriphosphazene-co-4,4′-sulfonyldiphenol) (PZS) nanotubes were evaluated as an efficient adsorbent for the removal of Rhodamine B (RhB), a cationic dye from aqueous solution. The as-synthesized adsorbent (PZS nanotubes) were characterized by scanning electron microscopy (SEM), transmission electron microscope (TEM), Fourier transform infrared spectroscopy (FTIR) and N₂ adsorption/desorption isotherms. The factors influencing the adsorption efficiency and capacity had been systematically studied. Results showed that the adsorption was highly dependent on temperature, initial RhB concentration and adsorbent dose. Effects of initial solution pH indicate that the adsorption can proceed in both basic and acidic environment. The equilibrium absorption capacity at 25°C can reach up to 35.58 mg/g within 60 min implying the adsorption procedure was highly rapid. The kinetic data was better described by the pseudo-second-order model with the correlation coefficient (R² = 0.9981), and the adsorption process followed Weber's intraparticle model, indicating the adsorption process could be divided into two stages. Results also showed that the adsorption equilibrium obeyed the Langmuir isotherm, and the value of equilibrium parameter R_L suggested that the PZS nanotubes were an efficient adsorbent for the removal of RhB from aqueous solution.     

Ultrasound-aided rapid and enhanced adsorption of anionic dyes from binary dye matrix onto novel hematite/polyaniline nanocomposite: Response surface methodology optimization

In recent times, polyaniline (PANI), a conducting polymer, has been studied widely for environmental remediation application due to its controllable electric conductivity with high surface area, which makes it a suitable adsorbent material. But lower mechanical stability of PANI is considered to be a serious drawback for its large-scale industrial application. To improve the mechanical strength of PANI, in this study, hematite nanoparticles were impregnated onto PANI by oxidative polymerization method in order to fabricate a novel organometallic nanocomposite (hematite-PANI-NC). The hematite-PANI-NC was used as adsorbent for removal of methyl orange (MO) and eosin yellow (EY) dye from binary dye matrix under ultrasonic-assisted adsorption. Excellent MO and EY dye removal (more than 98%) was observed from binary matrix at a wide solution pH from 2.0 to 6.0, and under ultrasound wave the adsorption equilibrium was achieved within 15 min only. Both MO and EY dyes adsorption experimental data strictly followed Langmuir isotherm, and maximum monolayer adsorption capacity of 126.58 mg/g and 112.36 mg/g was observed for MO and EY dye, respectively. The uptake mechanism of MO and EY dyes onto hematite-PANI-NC is governed by electrostatic interaction, π-π bonding and hydrogen bonding between dye molecules and nanocomposite. Response surface methodology analysis reveals maximum MO and EY removal of 98.43% and 99.35% at optimum experimental conditions. This study implies that the hybrid organometallic material hematite-PANI-NC has high potential for quick and enhanced sono-assisted uptake of anionic dyes from water near neutral solution pH.     

Adsorption of Li by a lithium ion-sieve using a buffer system and application for the recovery of Li from a spent lithium-ion battery

A lithium ion-sieve manganese oxide (MO) derived from Li-enriched MO was prepared by the glycolic acid complexation method. The Li adsorption performance in a LiCl–NH₃·H₂O–NH₄Cl buffer solution, simulated a spent lithium-ion battery (LIB) processing solution, and actual spent LIB processing solution were studied. An adsorption capacity of 27.4 mg/g was observed in the LiCl–NH₃·H₂O–NH₄Cl buffer solution (Li concentration of 0.2 mol/L, pH?=?9), and the adsorption behavior conformed to the Langmuir adsorption isotherm equation with a linear correlation coefficient (R²) of 0.9996. An adsorption capacity of 19 mg/g was observed in the simulated buffer spent battery solution (Li concentration of 0.15 mol/L, pH?=?7), and an adsorption capacity of 17.8 mg/g was observed in the actual spent battery solution (Li concentration of 0.15 mol/L, pH?=?7). X-ray diffraction, scanning electron microscope, and infrared spectrum results revealed that the structure and morphology of MO are stable before and after adsorption, and the adsorption of MO in all of the abovementioned buffer systems conforms to the Li⁺–H⁺ ion-exchange reaction mechanism. The lithium ion-sieve MO demonstrates promise for the recovery of lithium from spent LIBs.     

Preparation and characterization of nanocomposite,silica aerogel,activated carbon and its adsorption properties for Cd (II) ions from aqueous solution

A novel composite adsorbent, silica aerogel activated carbon was synthesized by sol-gel process at ambient pressure drying method. The composite was characterized by Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and Nitrogen adsorption/desorption isotherms (BET).In the present study, the mentioned adsorbent was used moderately for the removal of cadmium ions from aqueous solutions and was compared with two other adsorbents of cadmium, activated carbon and silica aerogel. The experiments of Cd adsorption by adsorbents were performed at different initial ion concentrations, pH of the solution, adsorption temperature, adsorbent dosage and contact time. Moreover, the optimum pH for the adsorption was found to be 6.0 with the corresponding adsorbent dosage level of 0.1 g at 60 °C temperature. Subsequently, the equilibrium was achieved for Cd with 120 min of contact time.Consequently, the results show that using this composite adsorbent could remove more than 60% of Cd under optimum experimental conditions. Langmuir and Freundlich isotherm model was applied to analyze the data, in which the adsorption equilibrium data were correlated well with the Freundlich isotherm model and the equilibrium adsorption capacity (q_e) was found to be 0.384 mg/g in the 3 mg/L solution of cadmium.     

新型芳香三嗪超交联多孔聚合物去除水溶液中甲基橙

Organic dyes, especially the harmful cationic dye methyl orange (MO), are emerging pollutants. The development of new materials for their efficient adsorption and removal is thus of great significance. Porous organic polymers (POPs) such as hyper-cross-linked polymers, covalent organic frameworks, conjugated microporous polymers, and polymers with intrinsic microporosity are a new class of materials constructed from organic molecular building blocks. To design POPs both with good porosity and task-specific functionalization is still a critical challenge. In this study, we have demonstrated a simple one-step method for the synthesis of the hyper-cross-linked aromatic triazine porous polymer (HAPP) via the Friedel-Crafts reaction. The resultant porous polymer was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, elemental analysis (EA), thermo-gravimetric analysis (TGA), solid-state ¹³C nuclear magnetic resonance (¹³C NMR), and nitrogen adsorption-desorption isotherms. The results show that HAPP is a rough, irregular morphology, porous organic polymer that is amorphous in nature. The novel polymer showed high Brunauer-Emmett-Teller surface area (of up to 104.36 m²∙g⁻¹), porosity, and physicochemical stability. Owing to the presence of N heteroatom pore surfaces in the network, the material exhibited a maximum adsorption capacity of 249.3 mg∙g⁻¹ for MO from aqueous solutions at room temperature. This is higher than that of some reported porous materials under the same conditions. To explain this phenomenon more clearly, theoretical quantum calculations were performed via the DFT method using Gaussian 09 software and Multiwfn version 3.4.1. It is performed to analyze the properties and electrostatic potential (ESP) of the HAPP monomer and MO. The results indicated that the N heteroatom of HAPP can easily develop strong interactions with MO, supporting the efficient adsorption of MO. The parameters studied include the physical and chemical properties of adsorption, pH, contact time, and initial concentrations. The percentage of MO removal increased as the pH was increased from 2 to 4. The optimum pH required for maximum adsorption was found to be 5.6. Adsorption kinetics data were modeled using the pseudo-first-order and pseudo-second-order models. The results indicate that the second-order model best describes the kinetic adsorption data. The adsorption isotherms revealed a good fit with the Langmuir model. More importantly, the HAPP can be regenerated effectively and recycled at least five times without significant loss of adsorption capacity. Therefore, it is believed that HAPPs with hierarchical porous structures, high surface areas, and physicochemical stability are promising candidates for the purification and treatment of dyes in solution.     

Cationic dyes adsorption onto high surface area ‘almond shell’ activated carbon: Kinetics,equilibrium isotherms and surface statistical modeling

Almond shell agricultural biomass was used to prepare high surface area activated carbon using potassium hydroxide as activating agent. The activated carbon (AC) was characterized using X-Ray photoelectron spectroscopy, X-Ray diffraction, Thermogravimetric and differential thermal analyses, Scanning electron microscopy, Fourier transform infrared, Brunauer–Emmett–Teller surface area and Raman spectroscopy. The AC was found to have a high surface area of 2054 m² g^?1. The influence of various key parameters was evaluated on the adsorption process including contact time, adsorbent dose and solution pH. Isotherm data were modeled using Langmuir and Freundlich models. Langmuir isotherm model presented the best fit to experimental data suggesting homogeneous distribution of adsorption sites. The adsorbent demonstrated high monolayer adsorption capacity of 833.33 and 625.0 mg/g for Methylene Blue and Crystal Violet, respectively. The efficiency of the adsorption process was linked to the micro-mesoporous structure and to the availability of the surface adsorption sites. Response surface methodology was used to optimize the removal efficiency from aqueous solution.     

Pb (II) removal from aqueous media by EDTA-modified mesoporous silica SBA-15

An organic-inorganic hybrid mesoporous silica material was synthesized by two-step post-grafting method of SBA-15 with 3-aminopropyltrimethoxy-silane (APTES) and thionyl dichloride (SOCl(2)) activated ethylenediaminetetraacetic acid (EDTA) in sequence and measured by means of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), elemental analysis (EA), transmission electron microscopy (TEM), nitrogen (N(2)) adsorption-desorption analysis and back titration. The material was found having the beneficial properties of mesoporous silica SBA-15 and EDTA. Adsorption potential of the material for Pb (II) removal from aqueous solution was investigated by varying experimental conditions such as pH, contact time and initial metal concentration. The removal efficiency of Pb(2+) was high under studied experimental conditions. The adsorption equilibrium could be reached within 20min and the kinetic data were fitted well by pseudo-second-order and intraparticle diffusion model. The adsorbent exhibited a favorable performance and its maximum adsorption capacity calculated by the Langmuir model was 273.2mgg(-1). Recycling experiments showed the adsorbent could be regenerated by acid treatment without altering its properties. The chemical states of the elements involved in the adsorption were analyzed by X-ray photoelectron spectroscopy (XPS). The results demonstrated that the adsorption mechanism of the material involved Na Pb ion-exchange and carboxyl group dominated surface complexation.     

Adsorptive Removal of Hg(II) from Synthetic and Real Aqueous Solutions Using Modified Papaya Seed

The performance of chemically modified papaya seed (CMPS) adsorbent with carboxyl and amino groups has been studied. Adsorption experiments were performed with respect to the changes in initial pH of the solution, contact time, initial Hg(II) concentration, and CMPS dosage. Kinetic data were fitted to the pseudo-second-order model. The maximum adsorption capacity calculated by Langmuir model was 18.34 mg/g. CMPS was characterized by elemental analysis, Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy. The results indicate that adsorption mechanism of CMPS involves ion exchange (2Na⁺/Hg²⁺) and carboxylic-group-dominated surface complexation. Regeneration study revealed that CMPS can be used successfully for four cycles with a small adsorption capacity loss (6.8%).