Biosorption of Cr(VI) from wastewater using Sorghastrum Nutans L. Nash

Sorghastrum Nutans L. Nash is used as an adsorbent for the removal of Cr(VI) from wastewater. Adsorption coupled reduction i.e. indirect reduction is the mechanism of Cr(VI) removal by the biomaterial. The adsorbent surface became highly positively charged at lower pH, adsorption rate of Cr(VI) is faster and reduction reaction also accelerates at lower pH since the binding of negatively charged Cr(VI) ion species to the cationic groups is enhanced and protons take part in this reaction. The adsorbent is characterised by using XRD, FTIR, SEM and EDAX analysis. OH bending, CN stretching/bending and NH stretching play a major role in Chromium adsorption. Experimental values follow pseudo-second order reaction and Langmuir adsorption isotherm. Surface diffusion is the rate controlling mechanism for the process. The maximum percentage of Cr(VI) removal obtained is 75.5% with 7?g/L dosage at pH 1.3 and adsorbate concentration was 100?mg/L. From the normal probability, residual, contour, 3D surface, main effect and interaction plot along with t-test, ANOVA, and F-test, it is observed that pH has the most significant effect on the percentage removal followed by adsorbent dosage and time. The adsorbate concentration has the least effects and interaction effects are found to be significant.     

Organic acid profile and phenolic and sugar content in Salix purpurea × viminalis L. cultivated with different spent mushroom substrate and copper additions

The aim of the study was to determine the response of Salix purpurea?×?viminalis L. growing on Pleurotus ostreatus spent mushroom substrate (SMS) with different copper (Cu) addition. The content of Cu in roots, leaves and shoots was reduced by SMS addition. A decrease of biomass was observed with simultaneous Cu concentration increase. SMS induced leaf and root elongation of Cu-treated plants. Variation in the profile of low molecular weight organic acids with the domination of oxalic and acetic acids was observed. The total phenolic content significantly increased for plants cultivated with SMS, while the biosynthesis of salicylic acid was considerably weakened. The content of sugars was generally reduced by SMS. Alteration in the level of the stress-related molecules suggests mitigation of the harmful effect of Cu on Salix hybrid metabolism by SMS addition. This pointed to the possibility of using SMS in contaminated soil to reduce the toxic effect of metals on plants used in phytoextraction.     

Potentiometric studies of mixed complexes of cobalt(II) and copper(II) with l‐Asparagine and adenine

A potentiometric titration technique has been used to determine the stability constants for the various complexes of Co(II) and Cu(II) with L‐asparagine and from DNA base, e.g. adenine. Stability constants of ternary systems have been evaluated by the method suggested by Irwing‐Rossotti. In addition, the conditional constants were calculated as a function of pH. The maximum values of the conditional formation constants were found to be in accordance with the mixed‐ligand complex formation constants in a determined pH region. Furthermore, the molar fractions of different species from mixed complexes were calculated by means of formation constants. The values of stability constants of mixed‐ligand complexes at 25°C are as follows: log K= 5.25 for Co(II)‐L‐asparagine‐adenine; log K= 9.30 for Cu(II)‐L‐asparagine‐adenine. The ionic strength was kept constant at I = 0.20 with NaClO₄.     

Voltammetric study on the interaction of the heavy metals Cd(II) and Mn(II) with transfer‐RNA,DNA and other polynucleotides

Small amounts of bivalent cations, usually provided by Mg²⁺, are in the living cell necessary for the biological activity of t‐RNA as these bivalent cations influence the tertiary and secondary structure of this globular polynucleotide.

In context with the discussed possibility of carcinogenic actions of ingested Cd it is of particular interest to check whether there exist specific strong interactions of this toxic heavy metal with nucleic acids.

Therefore, the binding of the toxic heavy metal ion Cd²⁺ and the essential heavy metal ion Mn²⁺ to t‐RNA and for comparison to DNA and the polynucleotides poly‐U, poly‐A and poly‐A‐poly‐U has been studied. Free metal ion concentrations have been determined by differential pulse polararography. Association constants and the number of binding sites have been evaluated by the Scatchard method and alternatively according to a simple electrostatic model of the polyelectrolytes. With the Scatchard method for t‐RNA and all polynucleotides with helical structure two different binding sites of different strength are observed. Those with higher association constants are assigned to the helical parts of t‐RNA. Interaction sites with low association constants correspond to the parts with no ordered tertiary structure, as their exclusive occurrence for poly‐U, having a completely stochastic coil structure, reflects. The values of the association constants for the stronger and weaker association sites are in the respective polynucleotides for both investigated bivalent metal ions of comparable magnitude. This emphasizes that the interaction is essentially of electrostatic nature and depends primarily on the charge of the interacting species.

Thus the specific strong interaction of Cd by the intercalation into the tertiary structure of nucleic acids or by chelation of their base units can be ruled out as one possibility for carcinogenity of Cd.

Moreover, under physiological conditions the high excess of competitive Mg²⁺ will suppress the interaction of Cd based on electrostatic forces.     

Mutagenic activity of transition‐metal complexes: Relation structure‐mutagenic and antibacterial activity for some Pd(II), Pt(II) and Rh(I) complexes†

The inhibitory and mutagenic action of some Pd(II), Pt(II) and Rh(I) complexes towards various bacterial strains has been evaluated, and some correlations have been found between the chemical behaviour of the complexes and their selective biological activity: most of the complexes cause only a DNA damage repaired by the excision repair system. Particularly, the Rh(I) complexes used in this work show selective antibacterial effects on defective but no effect on wild‐type strains.     

Territory and group sizes in Eurasian beavers (Castor fiber): echoes of settlement and reproduction?

According to current theories of territoriality, an animal is expected to defend the smallest area that can provide resources for maximisation of reproduction, known as the economically defendable area. In group territorial species however, the strategies behind resource defence are likely to be more complex with corporate territoriality, cooperative breeding, delayed dispersal and intra-group competition all potentially playing a role. Here we examined group territoriality in a social herbivorous rodent, the Eurasian beaver Castor fiber. Beavers in our study do not inhabit economically defendable territories. Instead the sequence of arrival of pairs into unoccupied areas seems to play a more important role in determining the size of the territory, whereas group size is determined by past reproductive success. We argue that the settlement pattern and reproductive history have a lasting impact in the territorial system of beavers due to a combination of the low adult mortality, high dispersal costs, and avoidance of resource depletion.R.D. Campbell and F. Rosell contributed equally to this work     

PCB and PCT levels in cultivated and free‐living mussels of galicia (North west Spain)

PCB and PCT residues were measured in free‐living (FM) and cultivated mussels (CM) from ten sites in Galicia by gas chromatography with electron capture detector and capillary column. The level of PCB₁₂₆₀ and PCT₅₄₆₀ in FMs increases going from Muros‐Noya to Vigo estuarine bay. There was a trend of increase from north to south.     

Approaching the binding between Cu(II) and aerobic granules by a modified titration and µ-XRF

Interactions between metals and activated sludge can substantially affect the fate and transport of heavy metals in wastewater treatment plants. Therefore, it is important to develop a simple, fast and efficient method to elucidate the interaction. In this study, a modified titration method with a dynamic mode was developed to investigate the binding of Cu(II), a typical heavy metal, onto aerobic granules. The titration results indicated that pH and ionic strength both had a positive effect on the biosorption capacity of the granular sludge. The µ-XRF results demonstrated that the distribution of metals on the granular surface was heterogeneous, and Cu showed strong correlations and had the same “hot spots” positions with other metal ions (e.g., Ca, Mg, Fe etc.). Ion exchange and complexing were the main mechanisms for the biosorption of Cu(II) by aerobic granules. These results would be beneficial for better understanding of Cu(II) migration and its fate in wastewater treatment plants.     

Hydrochemical and radiometric evaluation of fresh and thermal waters from Araxá city (Minas Gerais,Brazil)

Environmental Geochemistry and Health - This paper reports the hydrochemistry and activity concentration of the natural radionuclides 238U, 234U, and 210Po for three compartments of the...     

Synthesis and antifungal property of N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane and its derivatives

N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane and its derivatives were designed and synthesized. Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (¹H-NMR) techniques were applied to characterize chemical structures, and the filter paper disk method was used to test for antifungal effect of the products against Aspergillus niger, Paecilomyces variotii, and Paecilomyces lilacinus. Chemical structure charaterization showed that the products are target compounds. Antimicrobial experiment results indicated that N,N′-bis(trans-cinnamaldehyde)-1,2-diiminoethane displayed reliable antifungal effects against three fungi, and its antifungal effect is close to that of cinnamaldehyde. N,N′-bis(p-methoxy cinnamaldehyde)-1,2-diiminoethane and N,N′-bis(p-chlorocinnamaldehyde)-1,2-diiminoethane also showed antifungal effects at a low concentration. Of the two, N,N′-bis(p-methoxy cinnamaldehyde)-1,2-diiminoethane appeared to be more suitable as it was more effective at higher concentrations against Paecilomyces.     

Absorption and retention of polydimethylsiloxanes (silicones) in fish: Preliminary experiments†

Hydrophobicity and bioaccumulation potential of linear and cyclic polydimethylsiloxane (PDMS) oligomers were estimated by reversed‐phase liquid chromatography and feeding experiments with guppies (Poecilia reticulata). PDMS concentrations in fish were determined by capillary column gas chromatography and gas chromatography‐mass spectrometry. In contrast to polychlorinated biphenyls (PCBs), only very small amounts of PDMS were retained by the fish after six weeks feeding.     

Phenology and population radiation of the nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae) in Hawai’i

The nettle caterpillar, Darna pallivitta (Moore) (Lepidoptera: Limacodidae), is an invasive pest with established populations on three Hawai’ian islands. Indigenous to Southeast Asia, D. pallivitta caterpillars cause defoliation of ornamental nursery stock and pose a human health hazard due to their urticating hairs that can cause painful skin reactions. Identification of the pheromone component n-butyl (E)-7,9-decadienoate (E7,9-10:COOnBu) from D. pallivitta has made it possible to investigate the phenology and population dynamics using baited traps. Male captures in Jackson traps baited with E7,9-10:COOnBu showed a vegetation preference for tall-grass fields and forest/grass interfaces over forest areas. Microlocation preferences were also found for trap height, with over 65% of males being caught in traps suspended at 1 m, compared with the traps at 3 and 5 m. Captures of male moths in traps baited with live females, and direct observations of female calling behavior, showed peak activities 6–7 h after the onset of scotophase. This is a much later communication period than for D. bradleyi and D. trima and may provide a mechanism by which D. pallivitta maintains reproductive isolation in areas where all three species are present. Coastal and inland transects established in eastern Hawai’i measured aspects of population fluctuations and radiation into new areas with relation to elevation and microclimate. Population expansion was measured by comparing moth population means and 80% population boundaries over time. Both population measures showed a higher expansion for the coastal transect. Differences in population expansion may be attributed in part to temperature and elevation, while precipitation does not seem to have a strong effect. Both the behavioral and ecological data collected can be used to optimize deployment of detection/control strategies and to predict population expansion/risk assessment for establishing quarantine protocols for the nettle caterpillar.     

Antimutagenic and bacteriostatic activities of Schiff‐base compounds derived from aminoguanidine,semicarbazone and thiosemicarbazone and a copper(II)‐coordination complex

The Schiff‐base aminoguanidine compounds including a resorcylidene aminoguanidine copper(II) complex that were synthesized at our laboratory posses non‐mutagenic properties when tested with Ames test using Salmonella typhimurium TA97, TA100 and TA102 bacterial strains. These compounds were tested as possible pharmacological agents in preventing a wide array of illnesses. Additionally, some of these compounds exhibit strong antimutagenic and bacteriostatic activity. Nitrovin, a known mutagen, was used in the antimutagenicity tests as the inducer. A three‐dimensional projection of the copper(II) complex was derived by the semi‐empirical method ZINDO/1 to obtain additional information about its structure, and to help elucidate a possible mechanism of action.     

Input and fate of anthropogenic estrogens and gadolinium in surface water and␣sewage plants in the hydrological basin of Prague (Czech Republic)

The concentration of the estrogens 17β-estradiol, estriol, estrone, 17α-ethinylestradiol, mestranol and norethisterone and of the anthropogenic gadolinium (Gd_ant) has been determined in the creeks and rivers, sewage treatment plants and water works of the city of Prague. The rapid degradation of estrogens in surface water allows the estrogen concentration gradient to be used as a very precise and sensitive guideline by which to pin-point sewage leaks into surface run-off water. The rather conservative behavior of Gd_ant in surface and ground water documents in the present case the presence of sewage water in the surface water cycle.     

氢化物-无色散原子荧光法测定河水和废水中砷(Ⅲ)、砷(Ⅴ)、锑(Ⅲ)、锑(Ⅴ)、硒(Ⅳ)和硒(Ⅵ)

基于As (Ⅲ)、As(Ⅴ)、Sb(Ⅲ)、Sb(Ⅴ)、Sc(Ⅳ)、和Sc(Ⅵ)立不同酸度下,与硼氢化钾反应形成氢化物的行为,提出了测定水样中不同价态As、Sb和Se的原子荧光法:用HAC—NaAC缓冲液控制水样pH=5.5和PH=5.0分别测定As(Ⅲ)和Sb(Ⅲ)含量,水样加HCl至2N直接测定Se(Ⅳ);另取相同量的水样,经KI和抗坏血酸还原后分别测定总As和总Sb量,水样加HCl至6N煮沸后可测总Se量。用差减法求得相应的As(Ⅴ),Sb(Ⅴ)和Se (Ⅵ)含量,方法用于实际样品测定均得到满意结果。     

Growth pattern andβ-dimethylsulphoniopropionate (DMSP) content of green macroalgae at different irradiances

Growth rates and intracellular-dimethylsulphoniopropionate (DMSP) concentrations of five green algal species collected from different geographic regions in 1986 and 1989 were determined under four photon flux rates. InUlothrix implexa, U. subflaccida andAcrosiphonia arcta from Antarctica, growth was light-saturated at lower irradiances than in temperateUlva rigida from Southern Chile andBlidingia minima from Germany. The DMSP content ofUlothrix implexa, A. arcta andUlva rigida was directly correlated with the light factor: with increasing irradiance, algal DMSP level increased. In contrast, inUlothrix subflaccida andB. minima DMSP concentrations gradually decreased up to a photon flux rate of 30µmol m^–2 s^–1, then increased markedly under the highest photon flux rate tested. In non-growing, dark-incubatedA. arcta DMSP content was reduced by 35%, while the DMSP pool of all other species remained unchanged, at the level of pre-culture conditions. Under full darkness all plants exhibited a significantly higher DMSP concentration compared with algae grown at low photon flux rates of 2 to 30µmol m^–2 s^–1. These data show a correlation between growth pattern and DMSP biosynthesis, and may point to a species-specific minimum amount of light energy necessary for DMSP accumulation.Contribution no. 302 of the Alfred Wegener Institute of Polar and Marine Research     

Preparation and characterization of β-FeOOH-coated sand and its adsorption of Cr(VI) from aqueous solutions

Batch adsorption experiments were conducted to explore the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand. We investigated the key factors which affected the adsorption process such as adsorbent dosage, initial pH, initial Cr(VI) ion concentration, contact time and temperature. The uptake of Cr(VI) was very rapid and 44.3%, 51.6%, 58.9% of the adsorption happened during the first 180 minutes at 293K, 303K and 313K, respectively. The pseudo-second-order rate equation successfully described the adsorption kinetics. To study the adsorption isotherm, two equilibrium models, the Langmuir and Freundlich isotherms, were adopted. At 293K, 303K and 313K, the adsorption capacities obtained from the Langmuir isotherm were 0.060, 0.070 and 0.076 mg Cr(VI) per gram of the adsorbent, respectively. Thermodynamic parameters such as the change of energy, enthalpy and entropy were calculated using the equilibrium constants. The negative value of ΔG0 and the positive value of ΔH0 showed that the adsorption of Cr(VI) in aqueous solutions by β-FeOOH-coated sand was spontaneous, endothermic and occurred by physisorption.     

用松香共沉淀浮选河水中的痕量Cd~(2 )、Cu~(2 )、Mn~(2 )、Pb~(2 )、Zn~(2 )离子

本文用油酸钠作起泡剂,用松香共沉淀剂富集废水中的Cd~(2 )、Cu~(2 )、Mn~(2 )、Pb~(2 )、Zn~(2 )离子,火焰原子吸收分光光度法进行测定,精密度与回收率均较满意。