Toxicity of Nitroaromatic Compounds to Pseudokirchneriella subcapitata

Yang Chao Fen and Chen Chung Yuan

Nitroanilines and nitrotoluenes are semi-volatile compounds used in many industrial processes. However, there are insufficient data for assessing the risks of these compounds to phytoplankton. Furthermore, conventional algal toxicity tests (protocols) are inadequate for testing volatile and semi-volatile organic compounds considering the open test environment applied by these test methods. The present study evaluates the toxic effects of 25 nitroaromatic compounds using a closed-system algal toxicity test. The toxicity of various nitroaromatic compounds to green alga (Pseudokirchneriella subcapitata) was expressed in terms of median effective concentration and no-observed-effect concentration. Fourteen out of a total of 25 test chemicals were found to be either highly toxic (0.1 mg/L – 1.0 mg/L) or moderately toxic (> 1.0 mg/L – 10 mg/L), according to the USEPA descriptive categories of chemical. The modes of action of various nitroaromatic compounds were analyzed using HCA and PCA analyses, based on chemical’s toxicity and certain physical-chemical descriptors (i.e. hydrophobicity and the lowest unoccupied molecular orbital energy). The analysis indicates that compounds with nitro- substituent on the meta-site to an amine group on the benzene ring are polar narcotic or reactive in nature.

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Determination of total selenium in Helianthus Annuus L. in Turkey during 2 years by Graphite Furnace Atomic Absorption Spectrometry (GFAAS)

Karasakal A., Seren G. and Kalebasi Y.

The purpose of this study was to estimate total selenium concentration in Helianthus Annuus L. collected from different regions in Turkey by graphite furnace atomic absorption spectrometry (GFAAS), prior to microwave digestion. The accuracy of the techniques was evaluated by using certified reference material NIM-GBW07404 (GSS-4) and WEPAL-IPE-168 for soil and sunflower plant . The precision of the techniques, expressed as relative standard deviation, was observed under 8 % for GFAAS measurements. The concentrations of total selenium in plant , seed and soil collected from different regions were found in the range of 0.10–1.76 mg/kg for Helianthus Annuus L. in Turkey during 2 years.

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An environmentally friendly process to recover zinc from flue dusts of secondary copper industry

Li Q. and Zhao Y. C.

A clean route was developed to convert flue dusts of secondary copper smelters into value-added products. The process consists of microwave-assisted alkaline leaching and electrolysis. Initially, ~ 83 % Zn was dissolved in 5 M NaOH under microwave radiation (4 cycles of 30 s), whereas most of Cu was left in the residue. The rates of zinc recovery were significantly higher under microwave conditions as compared to those observed with conventional leaching. Furthermore, a better zinc selectivity and lower NaOH consumption were obtained. Then, the cementation by adding zinc powders was carried out to reduce the Pb and Cu to low levels (< 100 mg/L). Subsequently, ultrafine zinc powders were produced by electrolysis and the best performance occurred at T = 35oC, current density = 1000-1500 A/m2 with a solution composition of 30-40 g/L Zn and 180-220 g/L NaOH. The products were characterized by SEM, XRD and Malvern Laser Particle Size Analyzer. This clean method also promises to treat other industrial wastes containing Zn due to its low cost and simple design.

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Process research on recovering germanium from germanium waste through NaOH-H2O2 dissolve-hydrochloric acid distillation

Pu S. K., Lan Y. Z. and Li Y. J.

As to the regenerated germanium material derived from the infrared monocry stalline germanium process, due to the fact that lubricant, cooling agent are employed during the process, it is hard to extract germanium. So this study proposes that sodium hydroxide is used to decompose organics, metal state germanium is put into oxidizing dissolution process to become Ge (II) ion by hydrogen peroxide, as a result, forming sodium germanium, after being distilled the additional moisture, taking the over-dose sodium hydroxide of hydrochloric acid, the sodium germinate will become Ge4+ and germanium tetrachloride will be produced by employing the hydrochloric acid distillation separation method. Finally, through purification and hydrolysis, germanium dioxide of high purity will come into being. Compared with the other method of extracting germanium from regenerated germanium material, this process enjoys the following quality: germanium recovery rate is as high as 99.6%, less time used during the process without using any chlorine, avoiding the potential pollution chlorine put on the environment, high purity germanium tetrachloride produced, less consumption of material and lower cost involved in it.

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1-Butyl-3-Methylimidazolium Ionic Liquids -Environmentally Green Solvents for Extraction of Sulfur from Liquid Fuel

Dharaskar Swapnil, Varma Mahesh, Shende Diwakar, Yoo Chang Kyoo and Wasewar Kailas

A new class of green solvent, known as ionic liquids, has recently been the subject of intensive research on the extractive desulfurization of liquid fuels because of the limitation of the traditional hydrode- sulfurization method for removing thiophenic sulfur compounds catalytically. Aim of study is to investigate the possible application of ionic liquids as environmentally green solvent because of their unique physical and chemical properties. In this work, eight imidazolium ionic liquids were screened as green extractant for desulfurization of liquid fuel. The effects of reaction time, reaction temperature, sulphur compounds and recycling of best IL without regeneration on dibenzothiphene removal of liquid fuel were studied. Also, desulfurization of real fuels and multistage extraction with IL was studied. The results of this work provide meaningful insights in the understanding of the use of IL for deep desulfurization of liquid fuels.

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Equilibrium and kinetic modeling of chromium(VI) removal from aqueous solution by a novel biosorbent

Rangabhashiyam S., Anu N. and Selvaraju N.

The potential of a novel biosorbent Swietenia mahagoni fruit shell (SMFS) has been investigated for the confiscation of Cr(VI) from aqueous solution. The significant biosorption process parameters like pH, Cr(VI) concentrations and contact time were analyzed. Langmuir, Freundlich and Elovich isotherm models were used to model the adsorption equilibrium data. The Langmuir isotherm model better fitted the equilibrium data and the maximum adsorption capacity has been found as 2.309 mg g-1 .The kinetics studies demonstrated the pseudo first order rate lagergren model and pseudo second order. The biosorption process obeyed the pseudo second-order mode more than the pseudo first-order rate lagergren model. The biosorbent has been characterized through FTIR, SEM and EDAX respectively. The present studies revealed that SMFS could be subjected as an efficient biosorbent for the removal of Cr(VI) from aqueous solution.

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Evaluation of bioavailability of heavy metals and nutrients during agitated pile composting of green Phumdi

Singh W. Roshan, Pankaj Sashi, Singh Jiwan and Kalamdhad Ajay S.

The Loktak Lake of Manipur, India is being devastated due to high proliferation of phumdi (combination of different plant species). Composting of phumdi biomass is one of the best alternatives for protecting this lake from higher growth of unwanted weeds. Presence of heavy metals in final compost hinders its use as a soil conditioner but toxicity of heavy metals depends on bioavailability of heavy metals rather than the total concentration. The studies were carried out on physico-chemical parameters, bioavailability and leachability of heavy metals during agitated pile composting of harvested green phumdi biomass with rice husk and cattle manure in different combinations (Trials 1, 2, 3, 4 and 5). Results of present study showed that the maximum temperature about 46.8 ºC was monitored in trial 4 in comparison to other trials. Higher reduction of volatile solid (VS) was observed about 20.4% in trial 4 during the composting process. Total concentration of heavy metals and nutrients was enhanced during the process. Water solubility of nutrients (Na, K, Ca and Mg) was increased. The total Cu concentration was much less than total Zn content but water solubility of Cu (7.37-22.88% of total Cu) was more than Zn (2.95-4.48% of total Zn) which indicates Cu is more toxic than Zn even having very low concentration. Leaching test indicated that the heavy metals concentration in all trials was within the threshold limits for compost use for agriculture application. Present study concluded that composting of phumdi biomass with appropriate proportion of cattle manure is best substitute for reduction of bioavailability and leachability of heavy metals.

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Eutrophication of water reservoirs under anthropogenic, agricultural and industrial impacts (example of Southern Poland)

Rzetala Martyna A., Solarski Maksymilian, Pradela Alicja and Rzetala Mariusz

The purpose of the study was to identify the trophic level in retention water bodies located in Southern Poland (Central Europe). Thirty nine different water bodies were selected for study. In order to achieve the objectives of the study, the chlorophyll concentration was measured in the epilimnion layer of these reservoirs throughout the 2012 hydrological year. The water transparency during the summer season was also measured using the Secchi disc method. Based on the chlorophyll content and Secchi disc visibility, the Trophic State Index (TSI) values were calculated for chlorophyll α and Secchi disc visibility (Carlson method) and for chlorophyll α alone (Walker method). Additional measurements included the pH, dissolved oxygen, oxygenation and conductivity of the water. As demonstrated by the analyses conducted in the experiment, the annual average chlorophyll α content varied from approximately 2.5 ug/L in oligotrophic reservoirs (such as for example Pogoria III and Kuźnica Warężyńska), up to more than 70 ug/L in retention reservoirs holding strongly eutrophicated water (i.e. Rozlewisko Bytomki and Żabie Doły N). Water transparency ranged from over 5 m in oligotrophic reservoirs (5.1 m in Pogoria III and 5.5 m in Kuźnica Warężyńska), down to less than 0.5 m in hypertrophic reservoirs (Kamieniec – 0.35 m and Rozlewisko Bytomki - 0.45 m ). Based on the calculated TSI indicators and the classifications found in bibliographic sources covering chlorophyll content, the reservoirs covered by the study were classified according to their specific trophic type. There were three reservoirs classified as oligotrophic and eight as mesotrophic water bodies. There were 28 reservoirs at various stages of eutrophication, ranging from mesoeutrophic (3 reservoirs), eutrophic (18), to water bodies demonstrating seasonal or permanent signs of hypertrophy (7).

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Pollution characteristics and treatment effect of heavy metals in sediments from the Dianchi lake and inflowing rivers

Huang K., Jin Z. J., Li J. H., Yang F. L. and Zhou B. X.

This study provides the comprehensive analysis of pollution characteristics and treatment effect of heavy metals(Cu, Zn, Pb, Cd) in sediments from the Dianchi lake and inflowing rivers. The results revealed that the predominant chemical forms of Zn, Pb, Cd in the Dianchi lake sediments were Fe/Mn oxides and organic matter and sulfides; the concentrations of Cu, Pb, Zn and Cd in Caohai area were higher than the background concentrations. Potential ecological risk was used to assess heavy metals accumulation. The results indicated that Cu, Pb and Zn denoted low risk and Cd posed very high risk to local environment. In order to control heavy metal pollution, sediment dredging was conducted since 1998. The concentrations and ecological risk factors of heavy metals in dredging areas were lower than in reference points. Thus, dredging engineering and its post-processing technology and phytoremediation should be adopted, providing useful information for heavy metals pollution control in sediments from the Dianchi lake and its inflowing rivers.

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Studies on Arsenic (III) biosorption from aqueous solution by glutaraldehyde cross-linked chitosan beads

Madala Suguna and Nadavala Siva Kumar

In the present work, the ability of glutaraldehyde cross-linked chitosan beads (GCC beads) as synthetic adsorbent for adsorptive removal of As(III) from aqueous solutions is reported. GCC beads are synthesized by homogenous reaction of medium molecular weight chitosan in aqueous acetic acid solution with glutaraldehyde as cross linking agent. The biosorbent has been characterized by BET and FTIR techniques. The effects of experimental variable parameters such as pH, concentration of metal ion, amount of adsorbent, contact time and temperature on adsorption have been investigated. The optimum solution pH for adsorption of As(III) from aqueous solutions has been found to be pH 7.0. Based on R2 and error function values, it is observed that the kinetic data are better fitted to pseudo-second-order kinetic and chemisorption models. The experimental data have been analyzed using Langmuir and Freundlich adsorption isotherm models. The monolayer biosorption capacity of GCC beads as obtained from Langmuir isotherm at 350C is found to be 68.5 mg/g. The thermodynamic process is endothermic in nature and spontaneous. These studies consider the possibility of using GCC beads as cost effective adsorbent for the removal of As(III) from aqueous medium. So GCC beads could be an alternative for more costly adsorbents used for As(III) removal.

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Metachromatic Interactions of Orange (Citrus sinensis) Peel Polysaccharide with Cationic Dyes

Saha Amitabha and Bhaumik Samhita

Aqueous extract of the waste orange (Citrus sinensis) peel furnishes a polysaccharide material (OP1) which on saponification gives polysaccharide material (OP2) having equivalent weight 237±3. The saponified polysaccharide induces metachromasia in more aggregating thiazine dye 1,9-dimethylmethylene blue (DMMB, 1x10-5M) but fails to do so in potentially less metachromatic dye toluidine blue (TB, 2x10-5M) and methylene blue (MB, 2x10-5M).OP2 also induces strong metachromasy (blue shift ~110nm) in dye pinacyanol chloride(PCYN, 1x10-5M). Spectrum of aqueous solution of pseudoisocyanine chloride (PIC, 2x10-5M) has been found to remain unperturbed by OP2. Half plateau values signifying destruction of metachromatic compounds to the extent of 50% correspond to 12% and 21% ethanol for DMMB-OP2 and PCYN-OP2 systems respectively. The stoichiometry determination by isolation technique revels that DMMB and PCYN bind with OP2 in the molar ratio 1:1. Thermodynamic parameters obtained from spectral data indicate chromotropic character of the polysaccharide in interacting with the cationic dye molecule in solution.

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Simultaneous Quantification of Aspirin and Fluindione in a Tablet Formulation

Saravanan D. and Satheesh B

Simultaneous quantification of aspirin and fluindione in solid dosage form has been achieved by reversed-phase high-performance liquid chromatography on a Thermo Hypersil BDS C18 column (150 x 4.6 mm, 5 µm) with water and acetonitrile with 1% TFA as mobile phase and UV detection at 236 nm. The retention time of aspirin and fluindione were 1.4 and 3.1 min respectively with mean recoveries 100.1 and 100.3 %. The method was validated in accordance with ICH guidelines. Because of its simplicity with high precision and accuracy, the method can be used for the quantification of aspirin and fluindione in pharmaceutical preparations.

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Adsorption of Direct Red 28 from Aqueous Solution by Walnut Wood Shavings: : A Fixed Bed Column Study

Ertugay Nese

Walnut wood shavings used in experiments is an industrial waste which is relatively abundant. Inexpensive materials have been extensively investigated as adsorbent for removing contaminants from wastewater. In this study, the walnut wood shavings was tested for its ability to remove Direct Red 28 from aqueous solution by column experiments. All experiments were conducted in fixed-bed columns. Experiments were carried out as a function of liquid flow rate, initial dye concentration and bed height. The total adsorbed quantities and equilibrium uptakes of dye related to the effluent volumes were determined by evaluating the breakthrough curves obtained at different flow rates, inlet dye concentrations and bed height. The adsorption capacity increased with increasing bed height while decreased with increasing the inlet dye concentration and flow rate. The number of bed volumes (BV), the empty bed residence time (EBRT) and the adsorbent exhaustion rate (AER) were calculated at different flow rates, inlet dye concentrations and bed height. An increase in flow rate and inlet dye concentration resulted in a decrease in the bed volumes at the breakthrough. The column sorption process was found to perform better at lower inlet dye concentration, lower flow rate and higher bed depth. Column performance has been modeled by Adams–Bohart, Yoon-Nelson, Thomas and BDST models. The results obtained from the mathematical model were in good agreement with the experimental data which proved the success of the model in predicting the process.

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Adsorption process of heavy metals by low-cost adsorbent: A review

Aeisyah A., Ismail M. H. S., Lias K. and Izhar S.

In this study, the potential of various low-cost adsorbents for the removal of heavy metals from contaminated water has been reviewed. Various conventional methods for heavy metal removal such as precipitation, evaporation, electroplating and also ion exchange have been applied since previous years. However, these methods have several disadvantages: only limited to certain concentrations of metals ions, generation of large amount of toxic sludge. Capital costs are too high to be economical. Hence, adsorption using low-cost adsorbents is found to be more environmentally friendly. Adsorption is the alternative process for heavy metal removal due to the wide number of natural materials or agricultural wastes gathering in abundance from our environment. High adsorption capacities, cost effectiveness and their abundance in nature are the important parameters which explain why the adsorbent is economical for heavy metal removal. In this review, a list of adsorbents has been compiled to provide a summary of available information on a wide range of low cost adsorbents for removing heavy metals from contaminated water. The application of available adsorption models such as the isotherm, kinetics and thermodynamics as well as the influence of parameters on metal adsorption by low cost adsorbent shall be reviewed to understand the adsorption mechanism of low-cost adsorbents.

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