Investigation of solution chemistry effects on sorption behavior of Cu(II) on ZSM-5 zeolite

The sorption of Cu(II) from an aqueous solution using ZSM-5 zeolite was investigated by batch technique under ambient conditions. Sorption was investigated as a function of pH, ionic strength, foreign ions, humic substances, and temperature. The results indicate that the sorption of Cu(II) on ZSM-5 zeolite is strongly dependent on pH. Sorption is dependent on ionic strength at low pH, but independent of ionic strength at high pH values. The presence of humic/fluvic acid (HA/FA) enhances the sorption of Cu(II) on ZSM-5 zeolite at low pH values, and reduces Cu(II) sorption at high pH values. Sorption isotherms were well simulated by the Langmuir model. Thermodynamic parameters (i.e., deltaH0, deltaS0 and deltaG0) for the sorption of Cu(II) were determined from temperature-dependent sorption isotherms at 293.15, 313.15, and 333.15 K, respectively. Results indicate that the sorption process of Cu(II) on ZSM-5 zeolite is spontaneous and endothermic.     

Inactivation of bacteria G(+)-S. aureus and G(-)-E. coli by phototoxic polythiophene incorporated in ZSM-5 zeolite

A new heterogeneous photocatalyst was prepared by oxidative polymerization of the thiophene with ferric chloride in the ZSM-5 zeolite type. The synthesized polythiophene absorbs radiation in the visible range of the electromagnetic spectrum and by illumination with visible light generates reactive oxygen species (ROS) in water medium. During illumination reactive hydroxyl radical was detected by the spin trapping EPR method. Efficiency of the photocatalyst was tested on the killing of Gram-positive bacteria Staphylococcus aureus and Gram negative bacteria Escherichia coli.     

Simultaneous extraction of Cr(VI) and Cu(II) from humic acid with new synthesized EDTA derivatives

Soil washing is one of the few permanent treatment alternatives for removing metal contaminants. Ethylenediaminetetraacetic acid and its salts (EDTA) is very effective at removing cationic metals and has been utilized globally. However it is ineffective for anionic metal contaminants or metals bound to soil organic matter. The simultaneous removal of cationic and anionic metal contaminants by soil washing is difficult due to differences in their properties. The present study evaluated the potential of a washing process using two synthesized EDTA-derivatives, C₆HEDTA (2,2′-((2-((carboxymethyl)(2-(hexanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid) and C₁₂HEDTA (2,2′-((2-((carboxymethyl) (2-(dodecanoyloxy)ethyl)amino)ethyl)azanediyl)diacetic acid), which consist of a hydrophilic polycarboxylic moiety and a hydrophobic moiety with a monoalkyl ester group. A series of equilibrium batch experiments at room temperature were conducted to investigate the efficacy of C₆HEDTA and C₁₂HEDTA as extractants for both oxyanion Cr(VI) and cationic Cu(II). Results showed that either C₆HEDTA or C₁₂HEDTA can extract both Cr(VI) and Cu(II) from humic acid simultaneously. However, C₆HEDTA was less effective for Cr(VI) probably because it has no surface activities to increase solubility of humic acid, like C₁₂HEDTA. Extraction of Cr(VI) was mainly attributed to the decreased surface tension and enhanced solubility of organic matter. Extraction of Cu(II) was attributed to both the Cu(II) chelation and enhanced solubility of humic acid. It was demonstrated that the hydrophilic polycarboxylic moiety of C₁₂HEDTA chelates cations while the monoalkyl ester group produces surface active properties that enhance the solubility of humic acid.     

Exposure to sublethal concentrations of Zn(II) and Cu(II) changes biochemical parameters in Leporinus obtusidens

The aim of the present study was to assess the effect of the exposure of Leporinus obtusidens (Piava) to zinc and copper on catalase activity in the liver, delta-aminolevulinate dehidratase (delta-ALA-D) activity in liver, muscle, brain and kidney, and thiobarbituric reactive species (TBARS) in brain, muscle and liver. In addition, hematological parameters were measured in blood. The fish were exposed to 10% and 20% of the derived LC(50) values, 2.3 and 4.6 mg Zn l(-1) and 0.02 and 0.04 mg Cu l(-1), and sampled on days 30 and 45. Exposure to Zn(II) and Cu(II) decreased hematological parameters and also delta-ALA-D activity mainly in liver and kidney at all concentrations tested. Liver catalase activity increased after zinc or copper exposure at all concentrations and exposure times tested. Thiobarbituric reactive substances (TBARS) increased in the brain and liver of the fish exposed to zinc(II) for 45 days at both metal concentrations. In muscle, zinc(II) increased TBARS production at both exposure times and concentrations tested. Copper(II) exposure reduced the TBARS levels in liver at both concentrations and times tested. In brain, there was a decrease in TBARS levels only after 45 days of exposure. In muscle, this decrease was observed after 30 days of exposure at both concentrations. Although zinc and copper are required as microelements in the cells, our results showed that the sublethal concentrations of these metals can change biochemical parameters which may alter normal cellular function. These results pointed out the differential sensitivity of fish tissues to essential, but also toxic and environmentally relevant metals. The alterations of distinct biochemical parameters in fish tissues certainly contribute to the toxicity of Zn and Cu, and are of importance for an area that has been growing and has still been poorly explored in the literature.     

Impacts of pH and ammonia on the leaching of Cu(II) and Cd(II) from coal fly ash

Many coal-fired power plants are implementing ammonia-based technologies to reduce NO(x) emissions. Excess ammonia in the flue gas often deposits on the coal fly ash. Ammonia can form complexes with many heavy metals and change the leaching characteristics of these metals. This research tends to develop a fundamental understanding of the ammonia impact on the leaching of some heavy metals, exemplified by Cu(II) and Cd(II), under different pH conditions. Batch results indicated that the adsorption is the main mechanism controlling Cu(II) and Cd(II) leaching, and high concentrations of ammonia (>5,000 mg/l) can increase the release of Cu(II) and Cd(II) in the alkaline pH range. Based on the chemical reactions among fly ash, ammonia, and heavy metal ion, a mathematical model was developed to quantify effects of pH and ammonia on metal adsorption. The adsorption constants (logK) of Cu(2+), Cu(OH)(+), Cu(OH)(2), and Cu(NH(3))(m)(2+) for the fly ash under investigation were respectively 6.0, 7.7, 9.6, and 2.9. For Cd(II), these constants were respectively 4.3, 6.9, 8.8, and 2.6. Metal speciation calculations indicated that the formation of less adsorbable metal-ammonia complexes decreased metal adsorption, therefore enhanced metal leaching.     

麦秆黄原酸酯对水中Cu(II)的吸附

采用农业废弃物麦秆为原料制备黄原酸酯,通过傅立叶变换红外光谱FT-IR、扫描电子显微镜SEM等技术对麦秆黄原酸酯物理化学性质进行表征,并对水中Cu2+进行吸附特性研究,考察了不同条件对Cu2+吸附效果的影响,并将其应用于跌水式吸附法对含重金属沼液进行处理,为麦秆黄原酸酯应用于实际污水处理提供理论参考。结果表明,麦秆黄原酸酯对Cu2+的吸附行为符合伪二级动力学吸附模型与Langmuir等温吸附方程,298 K时,Cu2+的饱和吸附量为28.33 mg/g,溶出率为4.97%,对Cu2+的固持能力较强;黄原酸酯跌水吸附法对于含量为50 mg/L以下的Cu2+废水去除率达到80%以上,对实际沼液中Pb、Zn、Cd、Cu的去除率为44.42%~90.16%,去除顺序为Cd>Pb>Cu>Zn。     

Removal of Pb(II), Cd(II), Cu(II), and Zn(II) by hematite nanoparticles: effect of sorbent concentration, pH, temperature, and exhaustion

Nanoparticles offer the potential to improve environmental treatment technologies due to their unique properties. Adsorption of metal ions (Pb(II), Cd(II), Cu(II), Zn(II)) to nanohematite was examined as a function of sorbent concentration, pH, temperature, and exhaustion. Adsorption experiments were conducted with 0.05, 0.1, and 0.5 g/L nanoparticles in a pH 8 solution and in spiked San Antonio tap water. The adsorption data showed the ability of nanohematite to remove Pb, Cd, Cu, and Zn species from solution with adsorption increasing as the nanoparticle concentration increased. At 0.5 g/L nanohematite, 100 % Pb species adsorbed, 94 % Cd species adsorbed, 89 % Cu species adsorbed and 100 % Zn species adsorbed. Adsorption kinetics for all metals tested was described by a pseudo second-order rate equation with lead having the fastest rate of adsorption. The effect of temperature on adsorption showed that Pb(II), Cu(II), and Cd(II) underwent an endothermic reaction, while Zn(II) underwent an exothermic reaction. The nanoparticles were able to simultaneously remove multiple metals species (Zn, Cd, Pb, and Cu) from both a pH 8 solution and spiked San Antonio tap water. Exhaustion experiments showed that at pH 8, exhaustion did not occur for the nanoparticles but adsorption does decrease for Cd, Cu, and Zn species but not Pb species. The strong adsorption coupled with the ability to simultaneously remove multiple metal ions offers a potential remediation method for the removal of metals from water.     

Regeneration of spent TiO2 nanoparticles for Pb (II), Cu (II), and Zn (II) removal

Spent sorbents in water treatment processes have potential risks to the environment if released without proper treatment. The aim of this work was to investigate the potential regeneration of commercially prepared nano-TiO₂ (anatase) for the removal of Pb (II), Cu (II), and Zn (II) by pH 2 and ethylenediaminetetraacetic acid (EDTA) solutions. The percent of metal adsorption/desorption decreased with the increasing number of regeneration cycles, and the extent of decrease varied for each metal. Competitive effects were observed for the adsorption/desorption of different metals when the nano-TiO₂ was regenerated by EDTA solutions. Nano-TiO₂ was able to treat simulated metal polluted water with greater than 94 % adsorption and greater than 92 % desorption after four cycles of regeneration using pH 2 solution. These results demonstrated that nano-TiO₂ can be regenerated and reused using pH 2 solution compared to an EDTA solution for aquatic metal removal, which makes nanosorbents promising and economically and environmentally more attractive in the application of water purification.     

The effect of triethylene tetramine upon the selective removal of nickel (II), iron (II), manganese (II) and tin (II) in rats

The distribution of Nickel-63, Iron-59, Manganese-54 and Tin-113 in plasma was studied in rats which received single intravenous (i.v.) injection of aqueous solutions of their salts alone, and in rats which also received single intramuscular (im) injection of triethylene tetramine (TETA). TETA was extremely effective in reducing the plasma concentration of Nickel-63 followed by that of Iron-59, Manganese-54 and Tin-113.     

Precipitation of Zn(II), Cu(II) and Pb(II) at bench-scale using biogenic hydrogen sulfide from the utilization of volatile fatty acids

Biological production of hydrogen sulfide (H(2)S) using sulfate-reducing bacteria (SRB) has important potential within environmental biotechnology. The aim of this work was to study the possibility of using SRB for the treatment of an acid mine drainage (AMD) at bench-scale. This process involved three stages: the optimization of H(2)S production through the utilization of total volatile fatty acids (TVFAs) by SRB, the establishment of a biofilm reactor for sulfide production, and the precipitation of metals by using the biologically produced H(2)S. The substrates used for TVFAs production consisted of papaya, apple and banana. The H(2)S produced from the degradation of TVFAs was utilized for the precipitation of a metal-contaminated effluent collected from Bolivar mine (Oruro, Bolivia). The maximum concentration of H(2)S obtained was approximately 16mM. Removal efficiencies of ca. 100% for copper, above 94% for zinc, and above 92% for lead were achieved.     

Study on the spectral and Cu (II) binding characteristics of DOM leached from soils and lake sediments in the Hetao region

Introduction

Dissolved organic matter (DOM) is the most active component in environmental system and its chemical and structural characteristics most likely influence its biodegradation. Four surface soil (0?C20?cm) and three core sediment samples (0?C10?cm) were collected from Wuliangsuhai Lake. The objectives of this study were to investigate the spectral properties and humification degree of DOM and to determine and discuss comparatively the complexing capacities and stability constants of DOM by Cu (II) in the Hetao region.

Materials and methods

In this study, fluorescence spectra and fluorescence quenching methods were used to evaluate the humification degree of DOM and calculate the complexing capacities and the stability constants between DOM and Cu (II).

Results and discussion

Two defined peaks, at wavelengths of 260??300?nm (peak I) and 300??350?nm (peak II), could be identified for soil DOM at a ???? value of 30?nm. In sediment DOM extracts, a third peak (III) was observed near 364?nm. The results show that there is a significant difference in the structure of DOM because of different sources. The humification degree is significantly higher for soil samples than those of sediment samples. The FT-IR spectra of DOM show that structure in sediment DOM is more functional groups than those in soil DOM. DOM has a stronger Cu binding affinity in soils than in sediment in the Hetao region, which may lead to potentially significant influence on the migration and transformation of Cu (II).     

Batch and continuous adsorption of Cu(II) and Zn(II) ions from aqueous solution on bi-functionalized sugarcane-based biosorbent

Environmental Science and Pollution Research - A new one-pot synthesis method optimized by a 23 experimental design was developed to prepare a biosorbent, sugarcane bagasse cellulose succinate...     

Effect of biochars on adsorption of Cu(II), Pb(II) and Cd(II) by three variable charge soils from southern China

The purpose of this study is to compare the relative contribution of different mechanisms to the enhanced adsorption of Cu(II), Pb(II) and Cd(II) by variable charge soils due to incorporation of biochars derived from crop straws. The biochars were prepared from the straws of canola and peanut using an oxygen-limited pyrolysis method at 350 °C. The effect of biochars on adsorption and desorption of Cu(II), Pb(II) and Cd(II) by and from three variable charge soils from southern China was investigated with batch experiments. Based on the desorption of pre-adsorbed heavy metals, the electrostatic and non-electrostatic adsorptions were separated. EDTA was used to replace the heavy metals complexed with biochars and to evaluate the complexing ability of the biochars with the metals. The incorporation of biochars increased the adsorption of Cu(II), Pb(II) and Cd(II) by the soil; peanut straw char induced a greater increase in the adsorption of the three metals. The increased percentage of Cd(II) adsorption induced by biochars was much greater than that for the adsorption of Cu(II) and Pb(II). Cu(II) adsorption on three variable charge soils was enhanced by the two biochars mainly through a non-electrostatic mechanism, while both electrostatic and non-electrostatic mechanisms contributed to the enhanced adsorption of Pb(II) and Cd(II) due to the biochars. Peanut straw char had a greater specific adsorption capacity than canola straw char and thus induced more non-electrostatic adsorption of Cu(II), Pb(II) and Cd(II) by the soils than did the canola straw char. The complexing ability of the biochars with Cu(II) and Pb(II) was much stronger than that with Cd(II) and thus induced more specific adsorption of Cu(II) and Pb(II) by the soils than that of Cd(II). Biochars increased heavy metal adsorption by the variable charge soils through electrostatic and non-electrostatic mechanisms, and the relative contribution of the two mechanisms varied with metals and biochars.     

Removal of Cu(II) from aqueous solution in a fluidized-bed reactor

In this study, a fluidized-bed reactor (FBR) was employed to treat copper-containing wastewater by mean of copper precipitation on the surface of sand grains. The conditions for optimum copper removal efficiency were also investigated. This technology was controlled so as to keep supersaturation low to induce the nucleated precipitation of copper coating on the sand surface in an FBR. The effects of relevant parameters, such as the pH value, the molar ratio of [C(T)] to [Cu(2+)], hydraulic loading and the types of chemical reagents used, were examined. The experimental results indicated that 96% copper removal efficiency could be achieved when the influent copper concentration was 10mg l(-1). The optimum chemical reagent was Na(2)CO(3); the molar ratio of [C(T)]/[Cu(2+)] was 2, and the optimal hydraulic loading was not be more than 25m h(-1). In addition, preventing homogeneous nucleation in the FBR was an important operation parameter. Homogeneous nucleation and molecular growth would lead to undesirable microparticle formation in the effluent. A good mixture of carbonate and copper in the presence of sand grains could reduce the level of homogeneous nucleation in the bottom of the reactor. Energy dispersive analysis (EDS) of X-rays provided insight into the copper coating on the sand surface, and element analysis indicated the weight percentages of CuCO(3) and Cu(OH)(2) in precipitate.     

Reduction of Ag(I), Au(III), Cu(II), and Hg(II) by Fe(II)/Fe(III) hydroxysulfate green rust

Green rusts are mixed Fe(II)/Fe(III) hydroxides that are found in many suboxic environments where they are believed to play a central role in the biogeochemical cycling of iron. X-ray absorption fine structure analysis of hydroxysulfate green rust suspensions spiked with aqueous solutions of AgCH(3)COO, AuCl(n)(OH)(4-n), CuCl(2), or HgCl(2) showed that Ag(I), Au(III), Cu(II), and Hg(II) were readily reduced to Ag(0), Au(0), Cu(0), and Hg(0). Imaging of the resulting solids from the Ag(I)-, Au(III)-, and Cu(II)-amended green rust suspensions by transmission electron microscopy indicated the formation of submicron-sized particles of Ag(0), Au(0), and Cu(0). The facile reduction of Ag(I), Au(III), Cu(II), and Hg(II) to Ag(0), Au(0), Cu(0), and Hg(0), respectively, by green rust suggests that the presence of green rusts in suboxic soils and sediments can have a significant impact on the biogeochemistry of silver, gold, copper, and mercury, particularly with respect to their mobility.     

Removal and mechanism of Cu (II) and Cd (II) from aqueous single-metal solutions by a novel biosorbent from waste-activated sludge

The removal and mechanism of Cu²⁺ and Cd²⁺ from aqueous single-metal solutions were investigated by using a novel biosorbent from waste-activated sludge. A series of adsorption experiments was designed to disclose the effects of the key factors on the adsorption capacity of the biosorbent for the metal ions. The mass ratio of the biosorbent to metal ion was optimized as 2 to balance the adsorption capacity and the removal efficiency. A right shaking speed (150 r/min) not only ensured enough contact frequency between the sorbent and the adsorbate but also reduced the mass transfer resistance. The natural pH value (about 5.5) of the metal solutions benefited a high adsorption capacity of the biosorbent and avoided the consumption of acid or base for pH adjustment. The adsorption reactions belonged to the endothermic process between 15 and 45 °C. As the scanning electron microscopy (SEM) images showed, the meshy structure with long chains and many branches was ideal for the biosorbent to quickly capture the metal ions. The energy-dispersive X-ray (EDX) spectra confirmed that the adsorbed metal ions lay in the precipitates of the adsorption reactions. According to the FTIR analyses, the functional groups responsible for Cu²⁺ adsorption majorly consisted of O–H, N–H, COOH, CONH₂, and the groups containing sulfur and phosphorus, while those for Cd²⁺ adsorption contained O–H, N–H, COOH, and CONH₂. The differences in the responsible functional groups explained the phenomenon that the adsorption capacity of the biosorbent for Cu²⁺ was higher than that for Cd²⁺.     

Simultaneous determination of Cd(II), Cu(II), Pb(II) and Zn(II) by derivative stripping chronopotentiometry in Pittosporum tobira leaves: a measurement of local atmospheric pollution in Messina (Sicily, Italy)

The purpose of this study is to investigate the bio-accumulation of Cd(II), Cu(II), Pb(II) and Zn(II) in Pittosporum tobira (Thunb.) Aiton leaves sampled in different zones of Messina, in order to assess the level of atmospheric metal deposition in correlation with the traffic volume. Derivative stripping chronopotentiometry was used as a practical, precise and sensitive technique to determine simultaneously Cd, Cu, Pb and Zn levels in Pittosporum leaves. In the optimised electro-chemical conditions, detection limits lower than 0.05 microg kg(-1) were achieved, whereas the accuracy, expressed as obtained recoveries from certified materials, was in the range 93.5-102.7%. The obtained data provided evidence that Cd and Pb levels significantly decreased from high to low traffic density zones (p < 0.005, ANOVA), whereas Cu and Zn are accumulated by plants particularly from the soil and their contents is not related to the traffic volume.     

EXAFS study of adsorbed Cu(II) on fly ashes with different residual carbon contents.

This work studied the speciation of copper species adsorbed onto the surface of fly ash using X-ray absorption spectroscopy (XAS). Experimental results verified that the chemical bond between Cu(II) and the surface of the fly ash was Cu-O. The data set was optimally fitted into the two atomic shells: the first shell containing O atoms and the second shell containing Cu atoms. The extended X-ray absorption fine structure (EXAFS) data also show that, in the first shell, about 2.03-2.41 nearest oxygen atoms surround the center Cu atom with a Cu-O bond distance of 1.96-1.99 A. The results further demonstrated that the bond distance slightly increased with an increasing carbon content of the fly ash.     

Cu(II)-Glyphosate system: A study by anodic stripping voltammetry and the influence on Cu adsorption by montmorillonite

The influence of the pesticide glyphosate (GPS) on the adsorption of Cu (II) on montmorillonite has been examined. The complexation of Cu(II) with GPS was studied using anodic stripping voltammetry in differential pulse mode (DPASV). It has been concluded that the complexes present a labile behaviour and GPS shows a low but noticeable degree of heterogeneity, probably due to complexation of Cu bv more than one GPS species. Cu(II) adsorption on montmorillonite is drastically decreased in the presence of GPS, due to several reasons: decrease in free Cu concentration due to formation of Cu-GPS complexes; surface loading of GPS on montmorillonite, obstructing interlamellar Cu²⁺ adsorption and competitive effect between protons and Cu²⁺ for interlamellar positions.     

Removal of Ni(II) and Cu(II) ions using native and acid treated Ni-hyperaccumulator plant Alyssum discolor from Turkish serpentine soil

Alyssum discolor biomass was collected from serpentine soil and was used for removal of metal ions. The plant species grown on serpentine soils are known to be rich with metals ions and thus have more capability for accumulating heavy metals. Native and acid-treated biomass of A. discolor (A. discolor) were utilized for the removal of Ni(II) and Cu(II) ions from aqueous solutions. The effects of contact time, initial concentration, and pH on the biosorption of Ni(II) and Cu(II) ions were investigated. Biosorption equilibrium was established in about 60 min. The surface properties of the biomass preparations were varied with pH, and the maximum amounts of Ni(II) and Cu(II) ions on both A. discolor biomass preparations were adsorbed at pH 5.0. The maximum biosorption capacities of the native, and acid-treated biomass preparations for Ni(II) were 13.1 and 34.7 mg g⁻¹ and for Cu(II) 6.15 and 17.8 mg g⁻¹ dry biomass, respectively. The biosorption of Ni(II) and Cu(II) ions from single and binary component systems can be successfully described by Langmuir and Freundlich isotherms. When the heavy metal ions were in competition, the amounts of biosorbed metal ions on the acid treated plant biomass were found to be 0.542 mmol g⁻¹ for Ni(II) and 0.162 mmol g⁻¹ for Cu(II), the A. discolor biomass was significantly selective for Ni(II) ions. The information gained from these studies was expected to indicate whether the native, and acid-treated forms can have the potential to be used for the removal and recovery of Ni(II) ions from wastewaters.