钙铝类水滑石的清洁制备及其对甲基橙的吸附

以氢氧化钙、氢氧化铝和碳酸钠为原料,利用清洁法制备了钙铝类水滑石,并探讨了制备方法对钙铝类水滑石吸附甲基橙(MO)性能的影响.通过X射线衍射仪(XRD)、红外光谱仪(IR)、比表面积分析仪、扫描电子显微镜(SEM)和X射线能谱仪(EDS)表征其组成与结构.结果表明,与传统共沉淀法相比,在相同吸附条件下,清洁法制备的钙铝类水滑石(Ca4Al-LDHs-1)对MO的吸附性能更优,MO的去除率(90.4％)是共沉淀法的5.5倍.此外,Ca4Al-LDHs-1对MO的吸附更符合准二级动力学模型,吸附等温线符合Langmuir等温方程,当MO初始质量浓度为600 mg/L时,Ca4Al-LDHs-1的平衡吸附容量达545 mg/g.     

Effect of pH and temperature on the ion‐exchange isotherm of Cd(II) and Pb(II) on clinoptilolite

The ion‐exchange equilibrium of Pb(II) and Cd(II) on clinoptilolite from different deposits was studied in this work. The Langmuir isotherm fitted the ion‐exchange equilibrium data of both ions better than the Freundlich isotherm. The capacity of the natural zeolite to exchange Cd(II) and Pb(II) increased, augmenting the solution pH. This behaviour was attributed to the interactions between the ions in solution and the surface charge of the zeolite. Moreover, the capacity of the natural zeolite to exchange Cd(II) and Pb(II) was increased when the temperature was raised from 15 to 35 °C. This tendency was explained by assuming that the ion exchange was an endothermic reaction. The selectivity of the zeolite for the metal cations decreased in the following order: Pb(II) > Cd(II). This order was not modified while reducing the solution pH, but the zeolite selectivity was increased. At pH 2 the selectivity of the zeolite for Pb(II) was nearly three times larger than at pH 4. Copyright © 2006 Society of Chemical Industry     

聚乙烯亚胺改性蔗渣纤维素/蒙脱土复合球的制备及对Cd(Ⅱ)的吸附

以甘蔗渣纤维素（SBC）和蒙脱土（Mt）为原料，碳酸钙为致孔剂，通过简单凝固浴法制备PEI-SBC/Mt复合小球。采用FTIR、SEM、XRD等对所制备的球形吸附剂结构进行了表征，并系统研究了该吸附剂对模拟废水中的镉离子Cd(Ⅱ)的吸附行为。结果表明，拟二级动力学模型和Langmuir模型能够准确描述吸附过程，在温度为25 ℃、pH=6、Cd(Ⅱ)初始质量浓度为600 mg/L时PEI-SBC/Mt对Cd(Ⅱ)的最大吸附量为234.3mg/L ，表明吸附过程是单分子化学吸附，PEI的加入为吸附剂吸附Cd(Ⅱ)提供了更多的活性位点。此外，吸附剂具有可重复使用性，经过5次循环吸脱附后，其吸附量只由原有的94%降至79.8%。     

炭黑/氢氧化镁协同阻燃硅橡胶的研究

研究炭黑/氢氧化镁、红磷/氢氧化镁和硼酸锌/氢氧化镁协同阻燃硅橡胶的效果。结果表明,与单独添加氢氧化镁阻燃硅橡胶相比,炭黑/氢氧化镁具有显著的协同阻燃效应,炭黑/氢氧化镁阻燃硅橡胶的氧指数增大;炭黑/氢氧化镁协同阻燃效果明显优于红磷/氢氧化镁和硼酸锌/氢氧化镁;添加炭黑有助于提高氢氧化镁阻燃硅橡胶的燃烧成炭率和质量保持率。     

Removal of Cd(II), Pb(II), Cu(II) and Ni(II) from water using modified pine bark

This paper describes the removal of Cd(II), Pb(II), Cu(II), and Ni(II) ions from aqueous solutions using chemically modified pine barks (Pinus nigra). In this article, effects of chemical modification methods on the adsorption capacity have been investigated. Changes of the surface properties were examined by the FTIR, SEM and zeta potential analyses. HCl, NaOH, Fenton reactive, polymerization, acetone, ethanol, chloroform, tetra ethylene glycol, diethyl ether and glycol were used for modification processes. Maximum adsorption capacities were obtained by modification with NaOH (13-20 mg/g), Fenton (12-17 mg/g) and polymerization (12-16.5 mg/g). These modification processes also decreased Chemical Oxygen Demand of water from 1820 mg/L for raw pine barks to 35 mg/L for NaOH modified barks. Adsorption capacities of adsorbents increased from 2 mg/g to 20 mg/g as a result of modification that accordingly increase adsorbent surface activity.     

二氧化钛柱撑膨润土对染料甲基橙的吸附行为

以sol-gel法制备TiO2溶胶和钇掺杂TiO2溶胶为柱化剂,制备出了TiO2柱撑膨润土和钇掺杂TiO2柱撑膨润土.X射线衍射分析表明经柱撑后的膨润土层间距明显增大,达1.9 nm以上,经500℃煅烧后其层间距稳定在1.8 nm以上.研究了甲基橙在4种TiO2柱撑膨润土上的吸附行为,结果表明4种TiO2柱撑膨润土吸附染料甲基橙的速率和吸附量均较大,其吸附动力学行为均遵循Bangham方程和Langmuir方程所描述的规律.平衡吸附量qe与平衡浓度ρe之间的关系符合Freundlich和Langmuir等温吸附方程.其吸附均为吸热过程,吸附热值在12～17kJ/mol,吸附表现为表面物理吸附和离子交换作用.     

ACFs吸附溶液中甲基橙的性能研究

利用扫描电子显微镜(SEM)、比表面分析仪和FTIR对活性炭纤维(ACFs)进行表征,并研究了ACFs对溶液中甲基橙的吸附性能。考察了吸附动力学、pH值、吸附温度及甲基橙溶液初始浓度对吸附性能的影响。实验结果表明,平衡吸附时间选取150 min,在溶液为中性条件下,溶液中甲基橙的去除率最高,溶液pH值为6时去除率达到最大值为93.45%;溶液温度为25℃时,ACFs的吸附效果最好;甲基橙的去除率随着甲基橙初始浓度增加而增大。等温吸附数据符合Freundlich吸附等温模型,吸附反应过程符合Langergren准一级动力学方程。     

聚氯化铝残渣制备CaFeAl-LDO及其对甲基橙的吸附

采用聚氯化铝生产中的压滤残渣（PACR）制备CaFeAl-LDO吸附剂,对吸附剂的结构、形貌等进行表征,并考察该吸附剂对甲基橙的吸附效果。结果表明,制备的吸附剂焙烧前具有类水滑石的结构,焙烧后其表面变得疏松多孔,有明显的断层及裂痕。BET分析数据显示,CaFeAl-LDO较PACR比表面积增大近1.5倍,FTIR分析也表明CaFeAl-LDO有效融合了Ca-Al和Ca-Fe型吸附剂的特征峰。吸附实验效果表明,CaFeAl-LDO吸附剂最佳焙烧温度为750 ℃,对甲基橙的吸附符合二级吸附动力学模型,吸附后的LDO经高温焙烧后可以循环使用至少5次。     

Hydrophobic magnesium hydroxide nanoparticles via oleic acid and poly(methyl methacrylate)-grafting surface modification

Hydrophobic magnesium hydroxide nanoparticles were obtained by means of grafting poly(methyl methacrylate) (PMMA) onto the surface of nanoparticles after oleic acid (OA) modification. The introduction of functional double bonds was firstly conducted on the surface of nanoparticles by OA modification, followed by dispersion polymerization on the particles surface in ethanol solution using methyl methacrylate (MMA) as monomer, azoisobutyronitrile (AIBN) as initiator and polyvinylpyrrolidone (PVP) as stabilizer to graft PMMA on the surface of OA-modified magnesium hydroxide. The obtained composite particles were characterized by XRD, FTIR, TGA, FESEM-EDS, and the compatibility with organic solution was determined by sedimentation test. The results show that the organic macromolecule PMMA could be successfully grafted on the surface of OA-modified magnesium hydroxide nanoparticles, with the dispersibility and the compatibility of nanoparticles greatly improved in organic phase.     

Pyromellitic dianhydride‐modified β‐cyclodextrin microspheres for Pb(II) and Cd(II) adsorption

In this work, the pyromellitic dianhydride (PMDA)‐grafted β‐cyclodextrin (β‐CD) microspheres have been prepared for the removal of lead and cadmium metal ions in aqueous solution by a batch‐equilibration technique. The effects of the pH of the solution, contact time, and initial metal concentration were studied. The adsorption capacities for the two metal ions increase significantly as a large number of carboxyl groups are present on the microspheres surface. The equilibrium process is better described by the Langmuir isotherm than the Freundlich isotherm. The maximum adsorption capacities are 135.69 and 92.85 mg g^?1 for Pb(II) and Cd(II), respectively. Kinetic studies show good correlation coefficients for a pseudosecond‐order kinetic model, confirming that the sorption rate is controlled by chemical adsorption. The regeneration of the adsorbent can be carried out by treating the loaded microspheres with 0.2 (mol L^?1) HCl obtaining high desorption rate for the two metal ions. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Structural characterization of three organically modified Cd(II) compounds

Based on a strategy of introducing the inorganic SCN⁻ group into CdX₂-organoamine system, three organically modified Cd(II) compounds as 1-D [H₂dmpip][CdCl₃(SCN)] (dmpip = N,N´-Dimethylpiperazine) 1, 2-D [Cd(SCN)₂(dach)] (dach = 1,4-Diazacycloheptane) 2 and mononuclear [CdI₃(Hdach)] 3 were obtained in H₂O/C₂H₅OH solutions under ambient conditions. X-ray single-crystal diffraction analysis revealed that compound 1 is diprotonated dmpip-templated chained cadmium-chloro thiocyanate, compound 2 is the first example of dach-extended layered cadmium-thiocyanato coordination polymer, and compound 3 is monoprotonated dach-coordinated mononuclear cadmium iodide. The photoluminescence analysis indicates that the title three compounds are the potential fluorescence materials.     

The adsorption behavior of Cu(II), Pb(II), and Co(II) of ethylene vinyl acetate‐clinoptilolite nanocomposites

In this study, ethylene vinyl acetate (EVA) was mixed with clinoptilolite (C), a natural zeolite, to prepare EVA‐C nanocomposites. The films were characterized by SEM‐EDS, XRD, and FT‐IR, and heavy metal removal was studied using the batch technique. The effects of the initial pH value and concentration of solutions, contact time, and filler dosage on the adsorption capacity of the composites were investigated. To study the influence of pretreatment on the filler, clinoptilolite was activated using KCl, NaCl, and HCl. Adsorption results show that equilibrium was reached after 24 h, and that sorption reached its maximum at pH values between 5 and 7. The selectivity trend was observed to be Pb > Cu > Co, which was consistent for both single and mixed metal‐ion solutions. Pretreatment significantly increased adsorption capacity of the composite, but was dependent on the conditioning reagent. Nanocomposites filled with HCl‐activated particles demonstrated a high adsorption capacity of between 70 and 80% for all three metals, while KCl‐activated particles were the least efficient with a maximum adsorption capacity of 69% for Pb(II), 54% for Cu(II) and 48% for Co(II). The adsorption data were then fitted to both Langmuir and Freundlich isotherms over the entire concentration range, and the Langmuir isotherm showed a better fit of the experimental sorption data than the Freundlich isotherm. The results obtained show that this simple methodology which can be up‐scaled has great potential for the preparation of a wide variety of similar particle‐filled adsorbent nanocomposites in other environmental remediation applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Sorption studies for Cd(II) sequestration from aqueous solution on chemically modified Albizia lebbeck

In the present work, a new sorbent was successfully prepared by chemically modifying pods of Albizia lebbeck (AL) by Fenton’s reagent, followed by sodium silicate. Sorption studies were carried out by batch process. The optimum pH was found to be 6. Equilibrium isotherm data were analysed by non-linear curve fitting analysis, to fit Langmuir, Freundlich and Temkin isotherm models. Based on the Langmuir isotherm model, maximum monolayer sorption capacity (qm) was found to be 21.22 mg.g^?1 at 50°C. Breakthrough and exhaustive capacities were found to be 10 and 50 mg.g^?1, respectively. Desorption study showed 95% recovery of Cd(II) ions.     

Application of chemically modified orange peels for removal of copper(II) from aqueous solutions

The present study concerns the process of chemical activation of agricultural waste, namely orange peels, to remove copper ions from aqueous solutions. In fact the use of orange peels without any pretreatment leads at the most a copper retention percentage of the order of 75%, whereas percentages over 99% could be achieved by means of chemical activations with sulphuric acid, caustic soda, methanol and acetic anhydride. A parametric study was also included, investigating the influence of the pH, initial concentrations of metal and the type of activation on the copper retention onto the orange peels. The results showed that saturation was reached after 10 and 5 min, for the cases of no pretreatment and the chemical activation of the orange peels, respectively. The pH study indicated that a value between 4 and 6 seemed to be the most adequate. The results did also show that the copper initial concentration value did have an influence on the retention capacity for the natural solid support. The sorption kinetic study showed that the process could be considered of a pseudo-second order, whereas the obtained equilibrium data were best fitted to the Freundlich model.     

Investigation of adsorption behaviors of Cu(II), Pb(II), and Cd(II) from water onto the high molecular weight poly (arylene ether sulfone) with pendant carboxyl groups

Three types of high molecular weight polyarylether adsorbents with different molar ratios of carboxyl and phenylene were designed and synthesized through direct polycondensation in mixture solvents. The as‐prepared polymers were characterized by FTIR, ¹H‐NMR, TGA, DSC, SEM, EDS, and GPC in order to study the regularity of polymeric adsorption/thermostability performances. Because of the highest molar ratio of carboxyl and phenylene, PAES‐C‐Na presented the highest adsorption capacity of Cu²⁺ compared to PAESK‐C‐Na and PAES; therefore, PAES‐C‐Na was opted to study the impacts of adsorbent dosage, pH, contact time, and initial concentration on the adsorption of Pb²⁺ and Cd²⁺. Moreover, a kinetic analysis revealed that the adsorption process followed pseudo‐second‐order model, while the thermodynamic experimental data properly fitted with the Freundlich model. The multi‐component competitive adsorption capacity followed the order Pb²⁺ > Cu²⁺ > Cd²⁺. Additionally, the regeneration tests indicated that PAES‐C‐Na still possessed the excellent adsorption capacity after several recycles. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41984.     

Grafting of acrylonitrile and methyl methacrylate from their binary mixtures on cellulose using ceric ions

Ceric ion‐initiated grafting on cellulose from a binary mixture of acrylonitrile and methyl methacrylate was carried out in heterogeneous and acidic conditions at 30 ± 0.1°C in a nitrogen atmosphere. To avoid the complexation of water molecules with Ce(IV) ions, the concentration of the nitric acid was taken to be more than the concentration of ceric ions. The effect of the feed concentration, reaction time, and ceric ions concentration on grafting were investigated at a fixed composition. To investigate the effect of monomer–monomer interactions on grafting, the graft copolymerization was also studied, using different feed compositions (f_AN) ranging from 0.25 to 0.80. In this range of feed composition, the synergistic effect of methyl methacrylate molecules has shown an important effect on acrylonitrile monomer and facilitate the incorporation of the acrylonitrile monomer into the grafted chains. The reactivity ratios of acrylonitrile and methyl methacrylate were calculated using the Mayo and Lewis method and were found to be 0.74 and 1.03, respectively. The average sequence lengths of the monomers (m̄M) were found to be dependent on the feed compositions and found to be arranged in alternate fashion in the grafted chains. The probability of the addition of a monomer (P_1,1) to the growing radicals on cellulose ended with its own type of monomer was found to be dependent on the feed composition. The composition of the grafted copolymers, homocopolymers, was determined by IR and elemental analysis for nitrogen. None of the grafted chain on cellulose was found to be made of a single type of monomer. The ceric ion consumption during grafting was found to be independent of the molarity of the feed but shown an appreciable change in the initial few hours of grafting. The variation in the values of the grafting parameters as a function of the reaction conditions is suitably explained. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 79: 767–778, 2001     

Synthesis,adsorption and selectivity of inverse emulsion Cd(Ⅱ) imprinted polymers

Inverse emulsion polymerization was employed to synthesize inverse emulsion Cd(II) imprinted polymers(IEII P). The morphology and functional groups of IEIIP were characterized by SEM,FTIR and TG. Static adsorption experiments and competitive adsorption test were used to evaluate the adsorption ability of IEIIP. The adsorption capacity of polymers could reach 86.7 mg·g~(-1) under the optimal adsorption conditions. The pseudo second order kinetic model and Langmuir isotherm model could be used to analyze the experimental data well. The adsorption process of IEIIP was chemical adsorption process and monomolecular type. Thermodynamic parameters showed that the adsorption process was endothermic and could occur spontaneously. The selectivity coefficients k of Cd~(2+)/Pb~(2+), Cd~(2+)/Zn~(2+) and Cd~(2+)/Cu~(2+) were 2.4998, 1.2437 and 4.6882, respectively. The proposed method provides a new thought for removing Cd(II) in water samples.     

含氮大分子吸附剂的制备及其对Cd(II)的吸附

利用三聚氯氰的温度梯度反应活性,在较低温度下,用多乙烯多胺与三聚氯氰进行亲核取代反应,合成出一种以三嗪环为连接点的不溶含氮大分子颗粒吸附剂(N-MGA),并将其用于去除水体中的Cd(Ⅱ).通过元素分析、FTIR和SEM对N-MGA进行表征,同时对Cd(Ⅱ)的吸附进行吸附动力学、等温吸附模型拟合和吸附机理进行研究,考察了溶液pH对Cd(Ⅱ)吸附性能的影响、吸附剂的吸附-解吸再生循环性能及结构稳定性.结果表明,该吸附剂对Cd(Ⅱ)的吸附机理是利用吸附剂氨基上氮的孤对电子与Cd(Ⅱ)的配位络合作用进行吸附,且吸附过程符合准二级动力学模型和Langmuir吸附等温线模型,最大吸附量可达539.1 mg/g,且对Cd(Ⅱ)的吸附较为容易,吸附能力较强;在Cd(Ⅱ)初始质量浓度为3636.5和70.0 mg/L时,对Cd(Ⅱ)的吸附率分别可达97.5％和99.9％,且10次吸附-解吸再生循环中吸附率维持在97.0％～98.2％,解吸率均在97.6％以上,吸附剂回收率均在92.0％以上.     

Removal of Fe(III) ion from aqueous solution by adsorption on raw and treated clinoptilolite samples

Iron (III) adsorption from aqueous solutions onto raw and pretreated clinoptilolite was investigated here. Various parameters for iron removal; initial solution pH, contact time and metal ion concentration were optimized. The equilibrium data were modeled by both the Langmuir and Freundlich adsorption isotherms at optimal conditions. Adsorption capacities of raw samples and those pretreated with Na₂S₂O₈ at 20 °C , 70 °C and with HNO₃ at 20 °C were all similar but samples pretreated with HNO₃ at 70 °C were significantly different; iron (III) removal from samples pretreated with HNO₃ decreased with increasing pretreatment temperature. Tests with Fe⁺³ solutions containing phenol, CsCl or KCl, indicated the continued presence of these ions in zeolite which either promoted or retarded the adsorption of iron. The Fe⁺³ adsorption capacity of clinoptilolite pretreated with HNO₃ at 70 °C was about two times greater with, than without, CsCl and KCl. The kinetics of iron adsorption from aqueous solution were also investigated using the first-order Lagergren equation and a pseudo-second-order model.     

水合氧化铁的制备过程对其吸附甲基橙的影响

以硝酸铁为原料,Na OH溶液为沉淀剂,通过恒p H沉淀法在p H为3~9范围内制得4种水合氧化铁(Fh),通过XRD、表面零电荷时p H(p Hpzc)测定、N2吸附-脱附法对其进行表征,以甲基橙(MO)为模拟污染物比较其吸附性能。结果表明,p H为5时制备的Fh(Fh5)对MO的去除率为92.8%,明显优于Fh3(34.1%)、Fh7(67.4%)和Fh9(53.7%)。4种Fh对MO的吸附规律符合Langmuir方程,为单分子层吸附。另外考察了沉淀剂类型(Na OH、NH3·H2O)和Fe(Ⅲ)浓度对Fh5吸附MO的影响。结果表明,以Na OH溶液为沉淀剂、Fe(Ⅲ)浓度为0.2 mol/L时制备的Fh5具有最佳的吸附性能。