Removal and recycling of copper from aqueous solutions using treated Indian barks

Removal of copper from aqueous solutions containing 100–1000 ppm, using different Indian bark species, was performed on laboratory scale. The percentage removal of metal ions depends on the solution pH, bark species and time. The efficiency of copper removal by the used raw barks increases with a rise of solution pH and reaches a maximum of about 65–78% around pH 4–5. However, the decontaminated aqueous solutions were colored due to the dissolution of soluble organic compounds contained in the raw bark. This increases the biological and chemical oxygen demand (BOD and COD) of the solutions as well as the total organic carbon content (TOC). For this reason, raw bark should be treated either by chemical or biological means. Such treatment will allow the extraction of the soluble organic compounds and increase the chelating capacity and efficiency of the treated bark. Depending on the pH value, the chelating efficiency of treated barks is about 1.2–2.2 times that of the raw ones. Moreover, the retention capacity of the Indian treated bark varies from about 42–51 mg/g of dry bark. It is equal to or higher than that of common European species. About 1.8 mols of H₃O⁺ are released, by the treated barks, for every mol of chelated copper ions. Moreover, scanning electron microscopy (SEM) observations show uniform distribution of metal ions throughout the copper saturated bark. Infra red (IR) spectra suggest that the copper ions are chelated to hydroxyl and/or carboxyl functional groups of organic compounds contained in the treated bark. It seems that the interaction of the copper ions with the bark follows a cation exchange mechanism. This hypothesis is supported by elution experiments that allow recovery of about 99% of the contained copper. The retention capacity of the treated bark is almost constant after five cycles of chelation–elution, suggesting that the ‘life time cycle' is sufficiently long for continuous industrial application. The spent copper loaded barks can either be incinerated or pyrolysed. It generates solids containing either ≈80% of CuO or ≈14% of Cu°, respectively. Such materials can be used either in the secondary or primary copper production, thus offering a friendly environmental solution of effluents' treatment. The suggested process can be used as an alternative to the classical technologies for effluent decontamination. It is also efficient for polishing effluents treated by other methods.     

Paramagnetic effects on solid state carbon-13 nuclear magnetic resonance spectra of soil organic matter

The effects of paramagnetic species on solid state 13C nuclear magnetic resonance (NMR) spectra were quantified in a series of doping experiments. The degree of signal loss caused by paramagnetic metals was shown to depend not only on the quantity, but also on the nature of the paramagnetic species, as well as the intimacy of contact with the organic substrate and the type of NMR experiment. Two mechanisms of signal loss were distinguished--signal loss via loss of magnetic field homogeneity, which affects all 13C nuclei in a sample, and signal loss via interaction between electronic and nuclear spins, the effects of which were localized to the close environment of the paramagnetic species. Loss of field homogeneity is important for manganese species, but not for copper species, and is equally important for both cross polarization and Bloch decay experiments. The interaction between electronic and nuclear spins is highly dependent on the spin-lattice relaxation rate constant of the free electron (T1e), as cations with very short T1e values (e.g., Pr3+) cause less signal loss than cations with longer T1e values (e.g., Cu2+, Mn2+). Cross polarization spectra are shown to be more susceptible than Bloch decay spectra to this mechanism of signal loss. Signal loss and increased relaxation rates brought about by paramagnetic species can be used to provide information on soil organic matter (SOM) heterogeneity in the submicron range. This is demonstrated for SOM doped with paramagnetic cations where selective signal loss and increased relaxation rates are used to determine the nature of cation exchange sites.     

液相光催化降解有机污染物的研究与进展

光催化技术是一种处理液相有毒有机污染物的新型技术。对有机废水的光催化降解进行了研究,综合论述了影响光催化效率的各种因素,如晶粒尺寸、pH值、光照强度、外加氧化剂等。同时,对提高光催化效率的途径以及光催化反应器的设计因素进行了讨论。     

CuSO4 treatment of nuisance algal blooms in drinking water reservoirs

Since the turn of the century, copper sulfate has been used extensively as an algicide to control nuisance algal blooms in drinking water reservoirs Recent experimental results have shown that the toxicity of copper to algae is determined by the activity of ionic copper, and not the total copper concentration The sensitivity of algae to ionic copper has been found to vary considerably for different algal species Chemical processes such as precipitation, complexation by dissolved organic substances, and adsorption by suspended material can be important in controlling the chemical speciation of copper added to drinking water reservoirs The copper sulfate dosage required for effective treatment of a reservoir is shown to depend on water chemistry and the copper sensitivity of nuisance algal species By evaluating copper chemistry and copper sensitivity of nuisance algal species it may be possible to obtain effective treatment with lower copper sulfate dosages in some reservoirs     

Enhanced transformation of lead speciation in rhizosphere soils using phosphorus amendments and phytostabilization: an x-ray absorption fine structure spectroscopy investigation

To formulate successful phytostabilization strategies in a shooting range soil, understanding how heavy metals are immobilized at the molecular level in the rhizosphere soil is critical. Lead (Pb) speciation and solubility in rhizosphere soils of five different plant species were investigated using extended X-ray absorption fine structure (EXAFS) spectroscopy and chemical extraction. The EXAFS analysis indicated that Pb occurred as PbCO (37%), Pb sorbed to organic matter (Pb-org: 15%), and Pb sorbed to pedogenic birnessite and/or ferrihydrite (Pb-ox: 36%) in the bulk soil. Comparison of the EXAFS spectra between bulk and rhizosphere soils demonstrated notable differences in fine structure, indicating that Pb species had been modified by rhizosphere processes. The estimated proportion of PbCO (25%) in the buckwheat soil was smaller than the other rhizosphere soils (35-39%). The addition of P significantly reduced Pb solubility in the bulk and rhizosphere soil except in the rhizosphere of buckwheat, for which the Pb solubility was 10-fold greater than in the other P-amended soils. This larger solubility in the buckwheat rhizosphere could not be explained by the total Pb speciation in the soil but was presumably related to the acidifying effect of buckwheat, resulting in a decrease of the soil pH by 0.4 units. The reduced Pb solubility by P amendment resulted from the transformation of preexisting PbCO (37%) into Pb(PO)Cl (26-32%) in the bulk and rhizosphere soils. In the P-amended rhizosphere soils, Pb-org species were no longer detected, and the Pb-ox pool increased (51-57%). The present study demonstrated that rhizosphere processes modify Pb solubility and speciation in P-amended soils and that some plant species, like buckwheat, may impair the efficiency of Pb immobilization by P amendments.     

In situ speciation studies of copper-humic substances in a contaminated soil during electrokinetic remediation

Speciation of copper-humic substances (HS) in the electrokinetic remediation (EKR) of a contaminated soil was studied by in situ extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge structure (XANES) spectroscopies. The least-square fits of the XANES spectra suggested that the main Cu species in the contaminated soil were Cu-HS (50%), CuCO(3) (28%), Cu(2)O (11%), and CuO (11%). The Cu-HS in the contaminated soil possessed equatorial and axial Cu-O bond distances of 1.94 and 2.17 A with coordination numbers (CNs) of 3.6 and 1.4, respectively. In the EKR process, the axial Cu-O bond distance in the Cu-HS complexes was increased by 0.15 A, which might be due to a ligand exchange of the Cu-HS with H(2)O molecules in the electrolyte. After 180 min of EKR, about 50% of the Cu-HS complexes (or 24% of total Cu) in the soil were dissolved and formed [Cu(H(2)O)(6)](2+) in the electrolyte, 71% (or 17% of total Cu in the soil) of which were migrated to the cathode under the electric field (5 V/cm). This work exemplifies the use of in situ EXAFS and XANES spectroscopies for speciation studies of Cu chelated with HS in the contaminated soil during EKR.     

Macroscopic and molecular investigations of copper sorption by a steam-activated biochar

Excessive Cu concentrations in water systems can negatively affect biological systems. Because Cu can form strong associations with organic functional groups, we examined the ability of biochar (an O-C-enriched organic bioenergy by-product) to sorb Cu from solution. In a batch experiment, KOH steam-activated pecan shell biochar was shaken for 24 h in pH 6, 7, 8, or 9 buffered solutions containing various Cu concentrations to identify the effect of pH on biochar Cu sorption. Afterward, all biochar solids from the 24-h shaking period were air-dried and analyzed using X-ray absorption fine structure (XAFS) spectroscopy to determine solid-phase Cu speciation. In a separate batch experiment, biochar was shaken for 30 d in pH 6 buffered solution containing increasing Cu concentrations; the Cu sorption maximum was calculated based on the exponential rise to a maximum equation. Biochar sorbed increasing amounts of Cu as the solution pH decreased from 9 to 6. The XAFS spectroscopy revealed that Cu was predominantly sorbed onto a biochar organic phase at pH 6 in a molecular structure similar to Cu adsorbed on model humic acid (Cu-humic acid [HA]). The XAFS spectra at pH 7, 8, and 9 suggested that Cu was associated with the biochar as three phases: (i) a complex adsorbed on organic ligands similar to Cu-HA, (ii) carbonate phases similar to azurite (Cu(CO)(OH)), and (iii) a Cu oxide phase like tenorite (CuO). The exponential rise equation fit to the incubated samples predicted a Cu sorption maximum of 42,300 mg Cu kg. The results showed that KOH steam-activated pecan shell biochar could be used as a material for sorbing excess Cu from water systems, potentially reducing the negative effects of Cu in the environment.     

Phosphorus speciation of sequential extracts of organic amendments using nuclear magnetic resonance and X-ray absorption near-edge structure spectroscopies

The chemical forms of phosphorus in organic amendments are essential variables for proper management of these amendments for agro-environmental purposes. This study was performed to elucidate the forms of phosphorus in various organic amendments using state-of-the-art spectroscopic techniques. Anaerobically digested biosolids (BIO), hog (HOG), dairy (DAIRY), beef (BEEF), and poultry (POULTRY) manures were subjected to sequential extraction. The extracts and residues after extraction were analyzed by solution (31)P nuclear magnetic resonance (NMR) and synchrotron-based P 1s X-ray absorption near-edge structure (XANES) spectroscopies, respectively. Most of the total P analyzed by inductively coupled plasma- optical emission spectroscopy in the sequential extracts of organic amendments was orthophosphate, except POULTRY, which was dominated by organic P. The labile P fraction in all the organic amendments, excluding POULTRY, was mainly orthophosphate from readily soluble calcium and some aluminum phosphates. In the poultry litter, Ca phytate was the main P species controlling P solubility. The recalcitrant fraction of BIO was mainly associated with Al and Fe. Those of HOG, DAIRY, and POULTRY were calcium phytate, which were identified only as organic species in the XANES spectra. The combination of the three techniques-sequential chemical extraction, solution (31)P NMR spectroscopy, and P 1s XANES-provided molecular characterization of P in organic amendments that would not have been possible with just one or a combination of any two of these techniques. Therefore, P speciation of organic amendments should use solid-phase and aqueous speciation techniques as deemed feasible.     

Nitrogen removal in laboratory model leachfields with organic-rich layers

Septic system leachfields can release dissolved nitrogen in the form of nitrate into ground water, presenting a significant source of pollution. Low cost, passive modifications, which increase N removal in traditional leachfields, could substantially reduce the overall impact on ground water resources. Bench-scale laboratory models were constructed to evaluate the effect of placing an organic layer below the leachfield on total N removal. The organic layer provides a carbon source for denitrification. Column units representing septic leachfields were constructed with sawdust-native soil organic layers placed 0.45 m below the influent line and with thicknesses of 0.0, 0.3, 0.6, and 0.9 m. Using a synthetic septic tank effluent, NO(3)-N concentrations at 3.8 m below the influent line were consistently below 1 mg L(-1) during 10 months of operation compared with a NO(3)-N concentration of nearly 12 mg L(-1) in the control column. The average total N removal increased from 31% without the organic layer to 67% with the organic layer. Total N removal appeared limited by the extent of organic N oxidation and nitrification in the 0.45-m aerobic zone. Design modifications targeted at improving nitrification above the organic layer may further increase total N removal. Increased organic layer thicknesses from 0.3 m to 0.9 m did not significantly improve average total N removal, but caused a shift in residual nitrogen from organic N to ammonia N. Results indicate that addition of a layer of carbon source material at least 0.3 m thick below a standard leachfield substantially improves total N removal.     

罐采样-GC/MS法测定环境空气中挥发性有机物

采用SUMMA罐采样,空气预浓缩与气相色谱/质谱联用技术,建立了39种常见挥发性有机物的分析方法。选取攀枝花市不同功能区的5个测点,采集了4个季度的环境空气样品220个,定性检出挥发性有机物54种,其中烃类占24%,卤代烃类占52%,含氧化合物占22%,其它化合物占2%。苯系物的检出率最高。定量的挥发性有机物最大浓度和平均浓度最高的项目均为苯,平均浓度4.59μg/m3,最大浓度29.8μg/m3。苯系物时间分布呈现出旱季高,雨季低的特点;日变化特征为早晨最高,整体呈下降趋势。     

A COLORIMETRIC METHOD FOR THE DETERMINATION OF TRACE COPPER CONCENTRATIONS IN WATER1

Trace quantities of copper (II) ion can be found in natural water as waste products from industrial, mining, and agricultural operations. Because low concentrations of copper can be toxic to plant life, many workers have devised methods of analysis for this metal in water. These methods require expensive equipment and skilled technicians. The described study illustrates a simple method in which copper (II) ion is concentrated by a batch ion exchange technique and estimated colorimetrically after formation of the blue triethylenetetramine complex. Using the visible absorption peak of the complex at 600 nm it was possible to obtain accurate estimations of original copper concentrations in the range 0.5-3 ppm. Using the complex absorption peak at 260 nm in the ultra-violet region of the spectrum increased the sensitivity by a factor of twenty. Because of the dependence of the complex formation reaction on solution acidity it is possible to optimize conditions for the detection of copper (II) in the presence of other metal ions. This type of method, which could be extended to the analysis of other metal ions, could be performed by a relatively unskilled technician under field conditions.     

应急修复耦合资源回收的实践-以一起化工企业突发环境事件为例

通过东莞市一起铜氨蚀刻液泄漏引致突发环境事件的应急处理过程,介绍了污染控制和应急修复技术的应用情况,通过将高浓含氨污水蒸发制取NH4Cl产品,以及将污水处理至优于《地表水环境质量标准》（GB3838-2002）之Ⅰ类水质要求,作为我国首例应急修复耦合资源回收制取化工产品的成功案例,为化工类企业突发环境事件的应急处理提供决策参考.     

Catalytic degradation of toxic organic dye using an aluminum-doped Cu0.4Zn0.6-xAlxFe2O4 (x = 0.0, 0.2, 0.4, 0.6) spinel ferrite in a photo-Fenton system

Catalytic activity of spinel ferrite in breaking down toxic dye materials are promising due to their uniqueness. In this study, aluminum-doped copper zinc ferrite, Cu_0.4Zn_0.6-xAl_xFe₂O₄ (x = 0.0, 0.2, 0.4, 0.6), a catalyst for toxic dye degradation is synthesized through chemical co-precipitation route. The formation of the spinel ferrite catalyst is initially confirmed by Fourier transform infrared spectra, which shows the frequency of metal-oxygen bond vibration at 539 and 427 cm⁻¹ attributed to the tetrahedral and octahedral sites respectively. Higher intensity sharp peak of X-ray diffraction for (311) plane is the evidence for the phase purity and the formation of spinel ferrite. The crystallite size is found to decrease with the increase of Al³⁺ ion. The surface structure of the obtained particles is investigated using a scanning electron microscope. Analyses of the material's magnetic characteristics using a vibrating sample magnetometer (VSM) revealed that it is, in fact, a soft magnet, as evidenced by the loop of its hysteresis, which is narrow. The catalytic degradation of methylene blue dye under the mechanism of the photo-Fenton process is studied with the obtained spinel ferrites and the result is found to be as high as 96.5%. The process follows pseudo-second order kinetics and the Langmuir isotherm.     

WATER RESOURCES AND HUMAN HEALTH: THE VIEWPOINT OF MEDICAL GEOGRAPHY1

ABSTRACT: Medical geography studies both areal patterns of human health and disease and the environmental and cultural factors that contribute to such conditions. In such studies water resources are of major importance, not only because they are essential for life and their scenic beauty is of inspirational value, but also because they are involved, directly or indirectly, in more than 80 percent of all disease. The direct involvements result from various disease causing agents sometimes found in surface or ground water organic ones such as bacteria, worms, etc., which are known as pathogens, and inorganic ones such as trace elements and synthetic toxic chemicals. Surface waters may have indirect effects also, for they may serve as habitats or breeding places for organisms that do not themselves cause human disease but that serve as vectors or hosts for such pathogens. This paper will discuss these various roles of water resources in both endemic and epidemic disease occurrences and ways in which various human activities domestic, economic, recreational, or religious — increase or reduce our exposure to such diseases.     

XANES spectroscopic analysis of phosphorus speciation in alum-amended poultry litter

Aluminum sulfate (alum; Al(2)(SO(4))(3).14H(2)O) is used as a chemical treatment of poultry litter to reduce the solubility and release of phosphate, thereby minimizing the impacts on adjacent aquatic ecosystems when poultry litter is land applied as a crop fertilizer. The objective of this study was to determine, through the use of X-ray absorption near edge structure (XANES) spectroscopy and sequential extraction, how alum amendments alter P distribution and solid-state speciation within the poultry litter system. Our results indicate that traditional sequential fractionation procedures may not account for variability in P speciation in heterogeneous animal manures. Analysis shows that NaOH-extracted P in alum amended litters is predominantly organic ( approximately 80%), whereas in the control samples, >60% of NaOH-extracted P was inorganic P. Linear least squares fitting (LLSF) analysis of spectra collected of sequentially extracted litters showed that the P is present in inorganic (P sorbed on Al oxides, calcium phosphates) and organic forms (phytic acid, polyphosphates, and monoesters) in alum- and non-alum-amended poultry litter. When determining land application rates of poultry litter, all of these compounds must be considered, especially organic P. Results of the sequential extractions in conjunction with LLSF suggest that no P species is completely removed by a single extractant. Rather, there is a continuum of removal as extractant strength increases. Overall, alum-amended litters exhibited higher proportions of Al-bound P species and phytic acid, whereas untreated samples contained Ca-P minerals and organic P compounds. This study provides in situ information about P speciation in the poultry litter solid and about P availability in alum- and non-alum-treated poultry litter that will dictate P losses to ground and surface water systems.     

Spectroscopic and wet chemical characterization of solid waste organic matter of different age in landfill sites, southern Germany

Landfill sites are potential sources of hazardous emissions by degradation and transformation processes of waste organic matter. Its chemical composition and microbial degradability are key factors for risk management, after-care, and estimation of potential emissions. The aim of the study is to provide information about composition and extent of transformation of waste organic matter in four landfill sites in Bavaria, Southern Germany by means of (13)C NMR spectroscopy, acid-hydrolyzable carbohydrates, chloroform-methanol extractable lipids, acid-hydrolyzable proteins, and lignin compounds after CuO oxidation. Ten samples of about 20 to 25 yr, 15 to 20 yr, and 5 to 10 yr of deposition each were taken at 2 m depth intervals by grab drilling till 10-m depth. Increasing temperatures from about 15 degrees C at 2-m depth to >40 degrees C at 10-m depth are found at some of the sites, representing optimum conditions for mesophile methane bacteria. Moisture contents of 160 to 310 g kg(-1) (oven dry), however, provide limiting conditions for anaerobic biodecay. Spectroscopic and chemical variables generally indicate a low extent of biodegradation and transformation at all sites despite a considerable heterogeneity of the samples. Independent of the time and depth of deposition more than 50% of the carbohydrate fraction of the waste organic matter provide a high potential for methane emissions and on-site energy production. There was no significant accumulation of long-chain organic and aromatic compounds, and of lignin degradation products even after more than 25 yr of rotting indicating higher extent of decomposition or stabilization of the waste organic matter. Installation of seepage water cleaning and recirculation systems are recommended to increase suboptimal moisture contents with respect to microbial methanogenesis, energy production, and long-term stabilization of municipal solid waste.     

电工电子产品燃烧产物的中毒危险评估

当电工电子产品陷入火灾后会产生含有毒性物质的燃烧产物,受害者吸入后会导致窒息或使感官或上呼吸道受到刺激,从而降低或失去逃生的能力,造成伤害或死亡。中毒危险评估是以毒物学、燃烧试验、化学分析等方法所获得的数据资料为依据,评估电工电子产品燃烧时使人体产生中毒危险的可能性。     

Reclamation of wastes contaminated by copper,lead, and zinc

Waste materials containing toxic levels of copper, lead, and zinc, such as mine and smelter wastes, present difficult conditions for the establishment of vegetation. This article reviews the many attempts which have been made to reclaim these wastes. Inert wastes from mining and quarrying operations, such as slate quarry waste and certain colliery shales, seem to be good materials for reclaiming wastes contaminated by copper, lead, and zinc. Organic wastes, such as sewage sludge and domestic refuse, may provide only a temporary visual improvement and stabilization of the toxic materials.Nontolerant plant materials may often be planted directly on modern waste materials, which are less toxic than they were in the past. However, tolerant plant materials are needed for revegetating waste materials produced by early and more primitive extraction methods.     

Copper cycle in China and its entropy analysis

Copper cycle analysis approaches have been broadly investigated for sustainable development of copper industry in China. There are four stages in the life cycle of copper products, including mining & processing, fabrication & manufacture, use and reclamation. The 2005 copper cycle in China, analyzed by copper-flow diagram of the copper products life cycle with time factor, indicates that the copper ore index and copper scrap index were 0.78 t/t and 0.063 t/t, respectively; and copper resource efficiency was 1.3 t/t. To ascertain the degree of both aggregating and dispersing of the copper in the life cycle of copper products, the substance flow analysis with the index of entropy and the calculating method of entropy was presented. The variation of entropy along copper cycle was calculated based on the analysis of the life cycle of copper products in China in 2005. The entropies at the five nodes along copper cycle were 0.26, 0.046, 0.24, 0.60 and 0.25, respectively. The variation ratio of relative entropy in the whole system was −2.9%, which showed the copper-contained materials were congregated after the whole products life cycle. The same method was also applied to the variation of entropy along copper products life cycle in China in 2002. The discussion was focused on the results of these two years. The values of entropy at the five nodes along copper cycle in 2005 were all lower than those in 2002. The entropy at the five nodes along copper products life cycle in 2005 was extracted through two scenes under different technical indices, including scene one: 0.26, 0.032, 0.23, 0.60 and 0.17, respectively; and scene two: 0.26, 0.023, 0.23, 0.60 and 0.096, respectively. The values of entropy are effectively reduced, especially from the fourth to the fifth node, which is the obsolete copper products reclaiming stage.     

Determination of phosphorus speciation in dairy manure using XRD and XANES spectroscopy

Intensive manure application is an important source of diffuse phosphorus (P) pollution. Phosphorus availability from animal manure is influenced by its chemical speciation. The major objective of this study was to investigate the P speciation in raw and anaerobically digested dairy manure with an emphasis on the calcium (Ca) and magnesium (Mg) phosphate phases. Influent and effluent from an on-farm digester in Wisconsin were sampled and sieved, and the 25 to 53 microm size fraction was dried for X-ray powder diffraction (XRD) and P K-edge X-ray absorption near edge structure (XANES) analyses. Struvite (MgNH4PO4.6H2O) was identified in both the raw (influent) and anaerobically digested (effluent) manure using XRD. Qualitative analysis of P K-edge XANES spectra indicated that the Ca orthophosphate phases, except dicalcium phosphate anhydrous (DCPA) or monetite (CaHPO4), were not abundant in dairy manure. Linear combination fitting (LCF) of the P standard compounds showed that 57.0 and 43.0% of P was associated with DCPA and struvite, respectively, in the raw manure. In the anaerobically digested sample, 78.2% of P was present as struvite and 21.8% of P was associated with hydroxylapatite (HAp). The P speciation shifted toward Mg orthophosphates and least soluble Ca orthophosphates following anaerobic digestion. Similarity between the aqueous orthophosphate (aq-PO4), newberyite (MgHPO4.3H2O), and struvite spectra can cause inaccurate P speciation determination when dairy manure is analyzed solely using P K-edge XANES spectroscopy; however, XANES can be used in conjunction with XRD to quantify the distribution of inorganic P species in animal manure.