Untersuchung der Sorptionseigenschaften des Kationenaustauschers KB-2M mit Makronetzstruktur zur Abtrennung von Zinkionen aus Ab- und Spülwässern

Study of Sorptional Properties of the Cation Exchanger KB-2M with Macroreticular Structure for Recovery of Zinc Ions from Sewage and Rinsing Water Although a number of ion-exchange methods have been employed for the recovery of some transition metals from industrial effluents, knowledge about ion-exchange resins with macroreticular structure is poor. The present paper describes the mechanism of sorption on such exchangers and their application for recovery of zinc from sewage rinsing water. Ion exchanger of macroreticular structure are polymers with long-chained cross-linking agents. We have synthesized carboxylic ion-exchange resins by hydrolysis of copolymerisates of methyl acrylate with different cross-linking agents: divinylbenzene, divinyl sulfide, divinyl ester of ethylene glycol and divinyl ester of di- or triethylene glycol. The sorption process on modifications of the carboxylic resins KB-2 of various structure was studied with different methods: potentiometric titration, infrared spectroscopy, electron microscopy, X-ray structural analysis. The initial zinc concentration in rinsing water was 0.05 mol/L at pH from 3 to 6. For the sorption, 0.2…1.0 g of resin were equilibrated with 100 mL of zinc solution. After equilibrium (12 h), the resin was separated from solution. The zinc ions were determined by atomic absorption spectrometry after stripping with 100 mL of 10% sulfuric acid. The distribution ratio D was calculated (D: mmole of Zn sorbed per gram of resin divided by mmole of Zn per millilitre of solution). By means of infrared spectroscopy, the mechanism of sorption of zinc ions from rinsing water was determined. There may be a possibility of the formation of complexes in the cation-exchange resin phase. It was found out in this paper that the cation-exchanger KB-2M of macroreticular structure is the most effective for the sorption of the Zn²⁺-ions from sewage and rinsing water.     

Sorption Preconcentration and Determination of Cobalt in Industrial Solutions by Diffuse Reflection Spectroscopy Method

Cobalt and its compounds have a broad field of application in Russian industries, being essential raw materials for metallurgy, medicine, and agriculture. That is why the production of cobalt is one of the key industries in Russia. Cobalt is produced from mineral raw materials as well as from secondary raw materials (for example, after processing of spent catalysts of oil refinery). It can also be obtained as a by‐product of nickel, manganese, and some other metals processing. That is the reason why the solutions of Ni and Mn industries contain up to 50 g/L of cobalt. obalt compounds are harmful for men’s heart, bloodvessel system, and thyroid gland. This fact explains the importance of the monitoring of cobalt concentrations in natural water and sewages. This task can be effectively achieved using the analytical sorption technique. The present work is focused on the preconcentration of cobalt and its determination by means of diffuse reflection spectroscopy. The preconcentration of cobalt was carried out using the macronetwork cation exchangers KB‐2M and KB‐2‐3T synthesized on the basis of methyl acrylate and long‐chain cross‐linking agents copolymers. Based on these collectors, a cobalt determination method in industrial solutions was worked out using solid‐phase spectroscopy. The colored surface compound to be determined was obtained by a preceding cobalt sorption on the resin and by subsequent treatment of the concentrate obtained with definite amount of nitroso‐R‐salt. The Co calibration curve is linear in the concentration range of 0.05...0.50 mg/L Co (sample volume is 50.0 mL) and the detection limit is 0.02 mg/L (1 μg absolute).     

Die Entfernung von Thiocyanationen aus wäßrigen Lösungen unter Verwendung stark basischer und schwach basischer Anionenaustauscher

After treatment of the anion exchanger resins from several manufacturers with FeCl₃ or CuSO₄ their capacity to take up thiocyanate ions increases by the factor 2 … 3. By regeneration with diluted sulphuric acid or hydrochloric acid after precipitation of the ferric or cupric hydroxide a thiocyanate solution of 10 and 15 g/l, respectively, is obtained, which can be reused. The hydroxides dissolved in acid are used for the treatment of the ion exchanger. The process is proposed for the regenerating of wastewaters containing thiocyanate.     

Eliminierung von Schwermetallen aus komplexbildnerhaltigen Abwässern durch Kalk-/Kreide-Fällung

A report is given on laboratory investigations into model waters containing Cu²⁺-, Ni²⁺- or Zn²⁺-ions and tartrate, citrate, NTA or EDTA as complexing agents. There were determined residual concentrations of the metal ions at different shares of complexing agents, which are achieved by the precipitation with lime and chalk. Chalk is added in order to secure the required exess of calcium ions without causing an overalkalinization of the water. In the range of pH = 8…9, however, residual concentrations lower than 1 mg/1 are achieved only for copper ions in the presence of tartrate.     

Sorption Behaviour of Phenols on Natural Sandy Aquifer Material during Flow‐through Column Experiments: The Effect of pH

Flow‐through column experiments were carried out to investigate the influence of pH on the sorption of three phenols (2‐methyl‐4, 6‐dinitrophenol, 2, 4, 6‐trichlorophenol, pentachlorophenol) onto a natural sandy aquifer material collected from a bank filtration site of River Elbe, Germany. For the phenols investigated, an increase in sorption (retardation) with decreasing pH is observed indicating a stronger sorption of the neutral species in comparison to that of the anions formed by dissociation. The anions of 2‐methyl‐4, 6‐dinitrophenol and 2, 4, 6‐trichlorophenol do not show significant sorption. On the contrary, pentachlorophenol showed sorption not only in neutral form but also in ionic form significantly which should be taken into account while assessing the fate and transport of such compound. A linear model based on the degree of protonation (calculated from pH and pK_a) can be used to resolve the apparent (observed) sorption coefficient (K_{d, app}) into its neutral (K_{d, n}) and ionised (K_{d, i}) components. Knowing pK_a, K_{d, n}, and K_{d, i} the apparent sorption coefficient for pH values other than experimentally investigated can be predicted.     

Laboratory Testing of Sulfamethoxazole and its Metabolite Acetyl‐Sulfamethoxazole in Soil

The fate of ¹⁴C‐labeled sulfamethoxazole and acetyl‐sulfamethoxazole in soil has been investigated with special respect to possible entry routes of human and veterinary pharmaceuticals into soil environments. Therefore, the stability of the test substances was monitored first in sewage sludge and bovine manure. Within the incubation period of 72 d, 1% at maximum of the initially applied radiotracers was released as ¹⁴C‐carbon dioxide while ?75% was transferred to non‐extractable residues that were operationally defined by the ethyl acetate extraction. Test‐sludge and test‐manure samples with defined aged residues were prepared and, supplementary to standard solutions, applied to silty‐clay soil samples. After standard and test‐sludge application, soil/water distribution coefficients of K_d < 5 L kg^–1 were determined revealing both test substances as potential leachers. In contrast, the sorption of sulfamethoxazole increased after test‐manure application (K_d > 10 L kg^–1). In the long‐term degradability tests, the metabolic fate of both test substances was characterized by the continuous decrease of extractable residues, resulting in disappearance times of DT₉₀ ? 33 d, and the increase of non‐extractable residues. Mineralization reached 11% at maximum. Thereby, the dynamics of these processes differed whether the test substances were applied via standard, test‐sludge or test‐manure application. This fact emphasized the relevance of entry route specific matrix effects on the fate of both test substances in soil.     

Der Einfluß der Komplexierung auf die Kupfertoxizität bei Blaualgen

Some aspects of the influence of copper speciation on toxicity for blue-green algae are reviewed. The experimental part concentrates on Oscillatoria redekei and Aphanizomenon gracile. The two investigated species produce strong extracellular copper complexing ligands: Oscillatoria redekei in the exponential and stationary growth phase, and Aphanizomenon gracile has a distinct detoxification capacity. The detoxification of copper by synthetic agents was investigated using ethylene-diamine-tetraacetic acid. Simultaneous addition of Cu²⁺ and Na₂EDTA gives evidence for a slow complexation reaction. Hence an excess of Na₂EDTA is necessary for a fast and complete detoxification of copper. Model calculations are reported to show that the precipitation of copper compounds is not probable under the conditions used.     

Study of the Interaction Mechanism in the Biosorption of Copper(II) Ions onto Posidonia oceanica and Peat

A systematic approach was used to characterize the biosorption of copper(II) onto two biosorbents, Posidonia oceanica and peat, focusing on the interaction mechanisms, the copper(II) sorption–desorption process and the thermal behavior of the biosorbents. Sorption isotherms at pH 4–6 were obtained and the experimental data were fitted to the Langmuir model with a maximum uptake (q_max) at pH 6 of 85.78 and 49.69 mg g^?1, for P. oceanica and peat, respectively. A sequential desorption (SD) with water, Ca(NO₃)₂, and EDTA was applied to copper‐saturated biosorbents. Around 65–70% copper(II) were desorbed with EDTA, indicating that this heavy metal was strongly bound. The reversibility of copper(II) sorption was obtained by desorption with HCl and SD. Fourier transform IR spectroscopy (FTIR) analysis detected the presence of peaks associated with OH groups in aromatic and aliphatic structures, CH, CH₂, and CH₃ in aliphatic structures, COO^? and COOH groups and unsaturated aromatic structures on the surface of both biosorbents, as well as peaks corresponding to Si? O groups on the surface of peat. The results of SEM‐EDX and FTIR analysis of copper‐saturated samples demonstrated that ion exchange was one of the mechanisms involved in copper(II) retention. Thermal analysis of biosorbent samples showed that copper(II) sorption–desorption processes affected the thermal stability of the biosorbents.     

Die Entfernung von Cadmiumionen aus Spülwässern der galvanischen Industrie mittels Ionenaustausch

In laboratory investigations with model waters, the behaviour of selected cation-exchange resins (Amberlite 200 C, Duolite C-25, Lewatit S-100, Wofatit KPS and Wofatit KS-10) is tested. The usable volume capacity of the resins in the forms of H, Na and NH₄ as well as the water content and the total volume capacity after 25 cycles of loading/regeneration are determined. It is recommended to use Amberlite 200 C and Wofatit KS-10.     

Determination of Copper in Water Samples after Solid‐phase Extraction Using Dimethylglyoxime‐modified Silica

This work describes the modification of silica gel with dimethylglyoxime, in order to prepare an effective sorbent for the preconcentration and determination of copper. The sorption capacity of dimethylglyoxime‐modified silica‐gel (DMGMS) was 71.37 mg g^–1 and the optimum pH for the quantitative recovery of copper was found to be 5.0. The optimum flow rate, sorbent amount, and sample volume were 1 mL min^–1, 300 mg, and 50 mL, respectively. 10 mL of 0.1 mol L^–1 HCl was the most suitable eluent. The detection limit of copper was 6.0 ng mL^–1. The recommended method, for the determination of copper, is simple and reliable, without any notable matrix effect and can be successfully applied to environmental water samples. Copper recovery in the range from 99–100% was obtained from seawater and thermal spring water using this method. The method was applied to standard reference materials, NIST‐1515 (apple leaves) and NIST‐1643e (simulated fresh water), for the determination of copper and the results were in good agreement with certified values.     

Effect of Complexing Agents on the Acute Toxicity of Copper to Common Guppy Lebistes reticulatus (PETERS)

The acute toxicity of copper and copper plus complexing agents to common guppy Lebistes reticulatus was studied for 96 h by a static bioassay technique. The addition of complexing agents viz. disodium salt of EDTA, citric acid, sodium thiosulphate and glycine in Cu²⁺ solutions caused a great decrease in the per-cent mortality as compared to that of Cu²⁺ test solutions alone. 10 mg/l of complexing agent was added in each copper concentration in all the test series. The 96 h LC₅₀ values and 95% confidence limits in mg/l of Cu²⁺ plus were 1.23 (0.95…1.65) for Cu²⁺ alone; 4.30 (4.04 … 4.55) for Cu²⁺ plus EDTA; 1.94 (1.69 … 2.18) for Cu²⁺ plus citric acid; 3.44 (2.96 … 3.74) for Cu²⁺ sodium thiosulphate and 2.29 (2.22 … 3.02) for Cu²⁺ plus glycine.     

Preparation,Characterization and Adsorption Mechanism of Cu(II) onto Protonated Rubber Leaf Powder

The adsorption of Cu(II) onto HCl treated rubber leaf powder (HHBL) was investigated in batch and column studies. The adsorbent was characterized by spectroscopic and quantitative analyses in order to understand the mechanism of copper adsorption. HHBL is mesoporous in nature as indicated by Bruneuer, Emmett and Teller (BET) analysis, and has various kinds of functional groups such as Si‐OH, ROH, RCOOH, RCOO^–, RNH₂, C‐O‐C and aromatic rings as detected by Fourier transform infrared (FTIR) spectroscopy. Copper adsorption was confirmed by scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy (EDS). The equilibrium process was described well by the Langmuir isotherm model, and a maximum adsorption capacity of 8.39 mg/g was recorded for the smallest adsorbent size (<180 μm). The two main adsorption mechanisms involved were ion exchange and complexation. The fixed bed column study demonstrated satisfactory applicability of HHBL in removing Cu(II) from aqueous solutions.     

Eliminierung und Rückgewinnung von Metallionen aus Abwässern — eine Übersicht

The present state and the trends of the recovery of heavy metals from wastewaters are presented. The classical precipitation techniques are insatisfactory due to increases of solubility in the presence of impurity ions and/or complexing agents. At present, ion-exchange processes constitute the most frequently used method of metal recycling with an effective enrichment of metal ions. For the effective separation of metals from solutions of a low concentration the electrolytic reduction demands large electrode surface areas. In cells with fixed-bed or fluidized cathodes one can obtain specific electrode surface areas of some 10³ m²/m^m3. For the future, processes of extraction and especially membrane separation will gain in importance. In the past few years, a large number of highly selective metal extracting agents as well as the liquid membrane permeation with suitable carriers were developed. Combinations of membrane separation processes with chemical reactions may attain the same importance, as e.g. ultrafiltration in connection with the fixation of metal ions to watersoluble polymers. In the long run, especially techniques will prevail which will not only result in metal enrichment but also in the recovery of the raw material water.     

Removal of Organic Pollutants from Wastewater Using Wood Fly Ash as a Low‐Cost Sorbent

In this study, untreated and treated wood fly ash (WA) was used as a low‐cost sorbent in batch sorption tests to investigate the removal of organic pollutants from a real wastewater generated by cleaning/washing of machinery in a wood‐laminate floor industry in Sweden. The experiments focused on the effect of the WA dosage and particle size on the removal efficiency for organic compounds. With a WA dosage of 160 g L^?1 and a particle size less than 1 mm, the reductions of chemical oxygen demand (COD), biologic oxygen demand, and total organic carbon were 37 ± 0.4, 24 ± 0.4, and 30 ± 0.3%, respectively. Pre‐treatment of WA with hot water improved the COD removal efficiency by absorption from 37 ± 0.4 to 42 ± 1.6% when the same dosage (160 g L^?1) was applied. Sorption isotherm and sorption kinetics for COD using untreated WA can be explained by Freundlich isotherm and pseudo‐second‐order kinetic models. Intra‐particle diffusion model indicates that pore diffusion is not the rate‐limiting step for COD removal. Based on the experimental data, WA could be used as an alternative low‐cost sorption media/filter for removal of organic compounds from real industrial wastewater.     

Sorptive Potential of Beach Sand to Remove Ni(II) Ions: An Equilibrium Isotherm Study

The potential to remove Ni(II) ions from aqueous solutions using sea beach sand, a carbonate‐quartz mineral, was thoroughly investigated. The effects of relevant parameters such as solution pH, adsorbent dose, metal ions concentration, and temperature on Ni(II) sorption onto beach sand were examined. The sorption data followed the Langmuir, Freundlich and Dubinin‐Radushkevich (D‐R) isotherms. The adsorption was endothermic in nature at ambient temperature and the computation of the parameters, ΔH, ΔS and ΔG indicated the interactions between sorbate and sorbent to be thermodynamically favorable. Equilibrium was achieved very quickly within 30 min of shaking. A pseudo‐first order Lagergren equation was used to test the adsorption kinetics. Other kinetic models, e. g., the Morris‐Weber and Reichenberg equations, were used to calculate the rate constant of intraparticle diffusion and the fate of the diffusion process, respectively. The influence of some of the common cations and anions were also a subject of this study.     

Präzipitation von Aluminium und Phosphat in Gewässern unter dem Einfluss von Versauerung

Precipitation of Aluminium and Phosphate Affected by Acidification Acidified waters often show elevated concentrations of Al (with up to 6 mg L^–1 being not unusual). A pH increase resulting e.g. from mixing with non‐acidified water or from biological activities may be linked with Al precipitation. Up to now, this phenomenon was described for acid mine drainages. This investigation focuses on a whitish precipitate naturally formed in a brook of an atmospherically acidified catchment in the Ore Mountains, Germany. Based on infrared spectra the precipitate was identified as an Al‐hydroxosulfate with crystal water. A simulation of natural conditions in the laboratory showed that Al precipitated only if sulfate or phosphate ions were added to the solution. In the case of sulfate being added, the infrared spectrum of the precipitate was similar to the natural precipitate. ²⁷Al NMR spectroscopy revealed tetrahedrally coordinated Al in some precipitates which evidences the participation of the tridecameric [Al₁₃O₄(OH)₂₄(H₂O)₁₂]⁷⁺ cation beside other polymeric Al cations. Precipitation experiments subjected to the given conditions showed that the phosphate elimination from solution with Al was much higher than with Fe. With Al and Fe added together, the P elimination rate was likewise high, and phosphate was bound onto Al in the precipitate. This was demonstrated by SEM‐EDX spectroscopy. Based on these results we present a possible reaction mechanism. The precipitation of Al together with P allows a significant retention of both elements in sediments because in contrast to Fe, Al immobilizes phosphate even under anoxic conditions.     

Biosorption of Heavy Metals in Leachate Derived from Gold Mine Tailings Using Aspergillus fumigatus

Leachate derived from bioleaching process contains high amount of metals that must be removed before discharging the water. Aspergillus fumigatus was isolated from a gold mine tailings and its ability to remove of As, Fe, Mn, Pb, and Zn from aqueous solutions and leachate of bioleaching processes was assessed. Batch sorption experiments were carried out to characterize the capability of fungal biomass (FB) and iron coated fungal biomass (ICFB) to remove metal ions in single and multi‐solute systems. The maximum sorption capacity of FB for As(III), As(V), Fe, Mn, Pb, and Zn were 11.2, 8.57, 94.33, 53.47, 43.66, and 70.4 mg/g, respectively, at pH 6. For ICFB, these values were 88.5, 81.3, 98.03, 66.2, 50.25, and 74.07 mg/g. Results showed that only ICFB was found to be more effective in removing metal ions from the leachate. The amount of adsorbed metals from the leachate was 2.88, 21.20, 1.91, 0.1, and 0.08 mg/g for As, Fe, Mn, Zn, and Pb, respectively. The FT‐IR analysis showed involvement of the functional groups of the FB in the metal ions sorption. Scanning electron microscopy revealed that surface morphological changed following metal ions adsorption. The study showed that the indigenous fungus A. fumigatus was able to remove As, Fe, Mn, Pb, and Zn from the leachate of gold mine tailings and therefore the potential for removing metal ions from metal‐bearing leachate.     

Hydrogeochemical balance of forest umbrisol profiles (‘Sierra de Gata’, central western Spain)

Three techniques for obtaining soil water solutions (gravitational and matrical waters extracted using both in situ tension lysimeters and in vitro pressure chambers) and their later chemical analysis were performed in order to know the evolution of the soil‐solution composition when water moves down through the soil, from the Ah soil horizon to the BwC‐ or C‐horizons of forest soils located in western Spain. Additionally, ion concentrations and water volumes of input waters to soil (canopy washout) and exported waters (drainage solutions from C‐horizons) were determined to establish the net balance of solutes in order to determine the rates of leaching or retention of ions. A generalized process of sorption or retention of most components (even Cl^?) was observed, from the soil surface to the C‐horizon, in both gravitational and matrical waters, with H₄SiO₄, Mn²⁺, Na⁺, and SO₄^2? being the net exported components from the soil through the groundwater. These results enhance the role of the recycling effect in these forest soils. The net percentages of elements retained in these forest soils, considering the inputs and the outputs balance, were 68% K⁺, 85% Ca²⁺, 58% Mg²⁺, 7% Al³⁺, 5% Fe³⁺, 34% Zn²⁺, 57% Cl^?, and 20% NO₃^?, and about 75% of dissolved organic carbon was mineralized. Copyright © 2007 John Wiley & Sons, Ltd.