Sorption of heavy metal ions by glass beads-immobilized calix[4]arenes derivative

Glass beads (GB) immobilized, 5,11,17,23-tetra-tert-butyl-25,27-diethoxycarbonylmethoxy-26,28-dihydroxycalix[4]arene (CA) are prepared and used as a new sorbent in sorption study of removal heavy metal ions. A calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique for sorbent of selected heavy metal ions in aqueous. In order to absorb selected heavy metal ions in aqueous, a calixarene derivative bonded to amino-functionalized glass beads sorbent was synthesized via a self assembly technique. The sorbent which is named GB-APTS-CA was characterized using infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), elemental analysis and thermal analysis (TGA/DTG). The influences of some experimental parameters including pH of the sample solution, weight of sorbent, concentration and temperature have been investigated. The sorption data were evaluated using the Langmuir, Freundlich and Dubinin Radushkevich (D-R) isotherm. The obtained maximum sorption capacity for Cu(II), and Pb(II) is 0.06 mmol g^?1 and 0.02 mmol g^?1, respectively. Thermodynamic parameters such as the standard free energy change (ΔG○), enthalpy change (ΔH○) and entropy change (ΔS○) were calculated to determine the nature of sorption process. Thus, GB-APTS-CA is favorable and useful for the removal of Cu(II) and Pb(II) metal ions.     

重金属强化含金矿石的氰化浸出

通过分析铊、铋、汞和铅等重金属强化金氰化溶解的电化学原理,对含金氧化物矿石和难浸硫化物金精矿进行了重金属强化浸金研究.结果表明:重金属对金氰化溶解的阳极过程有显著的强化作用,但在常规供氧条件下,金的溶解速率并未显著提高;只有同时采用阴极强化措施,才能使重金属起到显著提高金溶解速率的作用;对于含金氧化物矿石,单独采用重金属强化即可明显提高浸金速率,如果在过氧化氢助浸的基础上添加重金属,金的浸出速率会有更大幅度的提高;对硫化物金精矿而言,单独采用重金属无明显强化效果,只有在添加过氧化氢作为辅助氧化剂的基础上,重金属对金的浸出才能起到强化的作用,该体系中过氧化氢起到了强化阴极过程和氧化硫化物的双重作用.     

Investigation of adsorption of heavy metal ions by natural aluminosilicate

The adsorption capacity of studied aluminosilicate samples was found to depend significantly on the sizes of grains of adsorbents. The equations for calculating the statistical exchange capacity of aluminosilicate of different fractions in relation to ions of heavy metals Ni(II), Cu(II), Zn(II), Fe(III), and Cr(III) were derived. The effective coefficients of diffusion in the adsorbent grain and in the film of solution were found. It was determined that external diffusion kinetics served as a limiting step of adsorption. The rate of the process was determined as varying from 0.16 × 10^–6 to 2.8 × 10^–6 mol/m² s.     

Sorption properties of fullerene-modified activated carbon with respect to metal ions

The prospects of modying of the activated carbon with microamounts of fullerenes, which can enhance its adsorption capacity with respect to metal cations by a factor of 2.5–5, are illustrated. The analysis of experimental data makes it possible to assume that silver ions are reduced on the carbon sorbent surface to metal silver, lead cations are sorbed due to the donor-acceptor interaction, and the copper ion sorption may lead to both the cation reduction to metal copper and the formation of complexes with different ligands preferentially with those containing an amino group. Original Russian Text ? V.V. Samonin, V.Yu. Nikonova, M.L. Podvyaznikov, 2008, published in Zashchita Metallov, 2008, Vol. 44, No. 2, pp. 204–206.     

Sorption properties of fullerene-modified polystyrene

Polystyrene is modified with fullerene, and composite films are obtained. The kinetics of sorption of heavy metal ions from aqueous electrolyte solutions on the initial and modified polystyrene films is studied. The efficiency of sorption of copper ions of the modified polymer is found to be four times higher than on the unmodified samples. The selectivity of sorption on the composite can be presented with the following order: Cu(II) ≥ Cd(II) > Ni(II) > Zn(II). The interaction between polystyrene and fullerene is studied by IR spectroscopy.     

Spectroscopic properties of Yb and Er ions in heavy metal glasses

Selected heavy metal glasses containing Yb³⁺ and Er³⁺ ions have been studied. Near-infrared luminescence spectra at 1.53 μm and up-conversion spectra of Er³⁺ ions were registered under excitation of Yb³⁺ ions by 975 nm diode laser line. The luminescence bands correspond to ⁴I_13/2-⁴I_15/2 (NIR), ⁴S_3/2-⁴I_15/2 (green) and ⁴F_9/2-⁴I_15/2 (red) transitions of Er³⁺, respectively. The optical transitions of rare earth ions have been examined as a function of glass host. The unusual large spectral linewidth nearly close to 110 nm for ⁴I_13/2-⁴I_15/2 transition of Er³⁺ ions in Yb-Er co-doped lead borate glass was obtained, whereas long-lived NIR luminescence at 1.53 μm was detected in lead germanate glass. The NIR luminescence and up-conversion phenomena strongly depend on stretching vibrations of glass host, which was confirmed by FT-IR spectroscopy.     

MgCl_2改性柑橘皮对水溶液中重金属离子的吸附性能

以柑橘皮(OP)为原料,通过MgCl2进行改性制备新型柑橘皮生物吸附剂MgOP。考察溶液pH值、温度、固液比、吸附时间和金属离子浓度对MgOP从单组分溶液中吸附Cu2+、Cd2+、Pb2+、Zn2+和Ni2+的吸附性能的影响。结果表明,pH值和固液比对吸附率的影响较明显;温度对吸附率的影响较小;所有吸附过程可在20 min内达到吸附平衡,对5种金属离子的吸附动力学均符合准二级动力学方程;与原始柑橘皮相比,MgOP对5种金属离子的最大吸附量显著提高;MgOP可重复使用10次以上;共存金属离子对吸附率影响很小。     

A mechanism of sorption of heavy metal ions from aqueous solutions by chemically modified cellulose

The effect of chemical modification on sorption properties of cotton cellulose with respect to Cu(II), Ni(II), and Fe(II) ions is studied. Modification was carried out through oxidation of cellulose with formation of dialdehyde cellulose, its further conversion to dialdoxime cellulose, and further to a sorbent with hydroxame acidic groups. The optimum conditions for cellulose modification were determined. The sorption capacitance of the modified sorbent is approximately twice as high as that of native cellulose; herewith, the time of establishment of equilibrium is reduced. The mechanism of chemisorption by modified cellulose is due to the presence of new sorption centers??hydroxame acidic groups??in the sorbent structure, alongside with ??-hydroxycarboxyl ones. The former, as opposed to the latter, form colored chelate complexes with heavy metal ions on the sorbent surface. Sorption isotherms are well described by the Langmuir model. The limiting sorption capacitance agrees with the amount of acidic groups of sorbents. This allows attributing such a sorbent to cationites and to interpret the mechanism of metal ion sorption from aqueous media by modified cellulose as ion exchange with the presence of -CHOHCOOH and -CONHOH functional groups.     

Removal of SO4, uranium and other heavy metal ions from simulated solution by sulfate reducing bacteria

In the case of in-situ leaching of uranium, the primitive geochemical environment for groundwater is changed since leachant is injected into the water bearing uranium deposit. This increases the concentration of SO4^2-, uranium and other heavy metal ions and results in the groundwater contamination. The effects of pH values of the simulated solution on the reduction of SO4^2- and the removal of uranium and other heavy metal ions by sulfate reducing bacteria（SRB） were studied. The results show that, when the pH value of the simulated solution is about 8, the reduction rate of SO4^2- by SRB and the removal rate of uranium, Mn^2＋, Zn^2＋, Pb〉 and Fe^2＋ will reach their highest values. A bioremediation technique for remediation of groundwater in in-situ leaching uranium mine can be developed.     

Preparation and characterization of novel dumbbell-like [60]fullerene polystyrene derivatives

The novel dumbbell-like [60]fullerene polystyrene derivatives were prepared by reaction of the “living” dianionic polystyrene with the fullerene core in C₆H₆/THF mixed solvents. The products were characterized by UV–VIS, FTIR, GPC and elemental analysis and it was proved that the products obtained under certain experimental conditions were linear dumbbell macromolecular structures. The GPC analysis showed that C₆₀-styrene copolymers and the pure polystyrene have nearly the same molecular weights. The TGA and EA results indicated that all of the copolymers have approximately the same C₆₀ contents.     

Thermodynamics and kinetics of adsorption for heavy metal ions from aqueous solutions onto surface amino-bacterial cellulose

Amino-bacterial cellulose (amino-BC) was prepared by chemical modification of bacterial cellulose(BC). The adsorption characteristics and mechanism of amino-BC were studied. The results show that adsorption data can be fitted well by Langmuir equation and the pseudo-second order kinetics, indicating that the adsorption of amino-BC would obey monolayer molecule adsorption and the main action was chemisorption. Meanwhile, the adsorption process was studied by the Elovich equation and the intra-particle diffusion model, indicating that the absorption characteristics of metal ions on amino-BC is controlled by both film diffusion and particle diffusion. The increase of reaction temperature will accelerate the adsorbing rate because of endothermic reaction.     

Photocurrent generation properties of electrochemically polymerized terthiophene-linked fullerene film

Terthiophene derivative of C₆₀ fullerene was synthesized. The polymerized film of this fullerene analog was prepared on an indium–tin-oxide electrode by electrochemical polymerization at +1.4 V versus a Ag wire. The absorbance of the polymerized film was increased by increasing the electrochemical polymerization time. The polymerized film generated stable photocurrents in the presence of triethanolamine. Optimization of the amount of adsorbed polymerized film for improving the photoelectric conversion performance was achieved by controlling the polymerization time.     

The use of cement kiln dust for the removal of heavy metal ions from aqueous solutions

Abstract

The possibility of removal and utilisation of heavy metal (HM) ions from aqueous solutions by cement kiln dust (CKD) has been studied. The experiments have shown that CKD may be used for industrial wastewater decontamination. They revealed that CKD may be used for neutralisation of acidic wastewaters (alkalinity 12–16 meq g^?1) and for removal of HM ions such as Cu(II), Ni(II), Pb(II), Cd(II) and Co(II). CKD acts as an alkaline agent and sorbent. The main crystalline components of CKD are: calcite, CaCO₃ (80% by mass), 10–15% SiO₂ and the remainder is basic calcium silicate, Ca₅(SiO₄)₂(OH)₂. The maximal capacity of CKD to remove Cu(II) is 0·29 g g^?1 CKD (9·1 meq g?1); Ni(II), 0·14 g g^?1 CKD (4·7 meq g^?1); Pb(II), 2·0 g g^?1 CKD (19 meq g^?1); Cd(II), 0·42 g g^?1 CKD (7·4 meq g^?1); and Co(II), 0·20 g g^?1 CKD (6·8 meq g^?1). Interaction of CKD with Cu(II) ions produces devillite Cu₄(CaSO₄)₂(OH)₆·3H₂O, with Pb(II) – basic carbonate Pb₃(CO₃)₂(OH)₂ and with Cd(II) ions – Cd(OH)Cl. The products of interaction of CKD with Ni(II) and Co(II) ions are amorphous: apparently hydrated Ni(OH)₂ and Co(OH)₂.     

Removal of SO_4~(2-),uranium and other heavy metal ions from simulated solution by sulfate reducing bacteria

In the case of in-situ leaching of uranium,the primitive geochemical environment for groundwater is changed since leachant is injected into the water bearing uranium deposit.This increases the concentration of SO_4~(2-),uranium and other heavy metal ions and results in the groundwater contamination.The effects of pH values of the simulated solution on the reduction of SO_4~(2-)and the removal of uranium and other heavy metal ions by sulfate reducing bacteria(SRB)were studied.The results show that,when th...     

氨基功能化CoFe2O4-SiO2 磁性复合材料的制备及其在去除水中重金属离子的吸附性能

钴-铁氧体纳米粒子(CoFe₂O₄ NPs)通过改良的共沉淀法制备,CoFe₂O₄-SiO₂磁性复合材料通过st?ber法合成,为了吸附重金属离子CoFe₂O₄-SiO₂进行了氨基功能化。这种吸附剂的晶体结构、形貌、颗粒尺寸、化学组成和分子结构采用X射线衍射图谱(XRD)、扫描电子显微镜(SEM)以及傅里叶变换红外光谱(FTIR)进行表征。此复合材料具有优良的磁性能,由于其高的饱和磁化强度,磁铁可以将其在30秒内快速分离。同时,CoFe₂O₄ NPs的磁性能可以通过烧结温度进行调节,随烧结温度提高,磁性能增强。溶液的pH及反应时间对重金属离子吸附的影响进行了研究,此外此吸附剂对Cu (II)、Cd (II)、Mn (II) 和Zn (II)具有较高的吸附容量和去除率,这一结果使此复合材料可以潜在应用于废水中重金属离子的吸附上。     

Surface deformation on azobenzene polymer film induced by optical near-field around polystyrene microspheres

The surface deformations of a urethane–urea copolymer containing azobenzene derivatives under the influence of the electric fields around polystyrene microspheres irradiated with polarized light were investigated. Monolayers of 500 and 100 nm diameter microspheres were formed on the copolymer surface and were irradiated with linearly polarized laser beam. After removing the microspheres, the copolymer surfaces were observed by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The dents were formed on the copolymer surface where the microsphere had been located. The 500 nm microsphere caused the dent with sides heaped up along the polarization of the incident light; the dent was similar to the one induced by Gaussian beam, indicating that the surface deformation had relation to the electric field around the microsphere. On the contrary, the dent induced by the 100 nm microsphere showed weak dependence on the polarization in shape. This is ascribed to the interaction between the optical near-field of the microsphere and the substrate surface.     

花球状Mg(OH)2的制备及其对重金属离子的快速高效去除(英文)

由MgSO₄废液制备球形花状Mg(OH)₂,并评估其对重金属离子的吸附性能。合适的制备条件为Mg²⁺浓度2 mol/L、Mg²⁺/NH₄OH摩尔比1:0.5、温度120℃和时间1h。由超薄片组成的球形花状Mg(OH)2对重金属离子具有良好的吸附能力,6min即可达到吸附平衡。20℃时Mg(OH)₂对Ni²⁺、Cu²⁺、Zn²⁺、Pb²⁺、Fe³⁺和Co²⁺的最大吸附量分别为58.55、85.84、44.94、485.44、625.00和27.86 mg/g。吸附过程符合Langmuir模型,为单分子层吸附。吸附动力学符合准二级动力学模型,化学吸附是其作用机制。球形花状Mg(OH)₂是合格的重金属离子吸附材料。     

Control of ultrafine microstructure by single-pass heavy deformation and cold forging of metal

A hot extrusion system with controlled cooling is investigated in this study. This system is used with the aim of manufacturing steel and other metal products with ultrafine microstructures by single-pass heavy deformation followed by controlled cooling. The continuous formation of bulk materials with the desired geometry and microstructure could be realized using the proposed system or by adding hot rolling stands after processing using the proposed system. Microstructure evolution during and after heavy single-pass deformation is examined through a series of experiments involving the hot extrusion of plain carbon steel followed by controlled cooling. The effects of severe plastic deformation on grain refinement and the mechanical properties of the formed products are discussed. It is clear that the use of the proposed system is helpful for the grain refinement of a cast microstructure. Also, ultrafine-grain steel with a grain diameter of 3 μm can be formed using the proposed system. Finally, the formability of the ultrafine-grain steel manufactured using the proposed system is examined by a cold-forging experiment.