ISRN Environmental Chemistry The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. Effect of Physical and Chemical Activation on the Removal of Hexavalent Chromium Ions Using Palm Tree Branches Wed, 02 Apr 2014 07:44:40 +0000 Nowadays the removal of heavy metals from wastewater is essential due to their high toxicity and impact on human health. In the present study, branches of palm trees were converted into activated carbon by chemical and physical activation. The prepared samples were used for the removal of Cr(VI) from their aqueous solution. Chemical activation was carried out using (20 and 50%) H3PO4 and K2CO3, and physical activation was performed using steam. Batch adsorption experiments were carried out to examine the removal process under factors such as pH and . The metal ion removal was pH dependent and reached maximum removal at pH 2. Experimental data were analyzed using Langmuir, Freundlich, and Flory-Huggins isotherms. The adsorption studies revealed that the removal of Cr(VI) ions was well fitted with Langmuir isotherm. The adsorption kinetics well fitted using a pseudo second-order kinetic model. Column studies revealed that the highest bed volume (60 BV) was observed for the sample activated with 50% H3PO4. The adsorption efficiency was enhanced with acid treatment (50% H3PO4) and reduced by steam. Soheir Khedr, Mona Shouman, Nady Fathy, and Amina Attia Copyright © 2014 Soheir Khedr et al. All rights reserved. Photosynthetic Active Pigments Changes in Norway Spruce (Picea abies) under the Different Acclimation Irradiation and Elevated CO2 Content Thu, 06 Mar 2014 20:08:28 +0000 Photosynthetic active pigments content (chlorophylls and carotenoids) in Norway spruce (Picea abies) needles was measured by absorption spectroscopy. Norway spruce was exposed to low and high photosynthetic active radiation and ambient and elevated CO2 concentration. It was investigated that combination of low photosynthetic active radiation and elevated concentration of CO2 resulted in stimulation of chlorophylls and carotenoids production. Combination of high photosynthetic active radiation and elevated CO2 concentration led to overall chlorophylls and carotenoids content decrease. Moreover, specific leaf area trend could be used as a potentially reliable indicator of plant stress response. Miroslav Kvíčala, Eva Lacková, and Lenka Urbancová Copyright © 2014 Miroslav Kvíčala et al. All rights reserved. Adsorption of Hexavalent Chromium from Aqueous Solution Using Chemically Activated Carbon Prepared from Locally Available Waste of Bamboo (Oxytenanthera abyssinica) Sun, 23 Feb 2014 09:05:48 +0000 This study reports on the adsorption of Hexavalent Chromium from aqueous solutions using activated carbon prepared from bamboo (Oxytenanthera abyssinica) waste by KOH activation heating in an electrical furnace at 1073 K for 3 hrs. Batch adsorption experiments were also carried out as a function of pH, contact time, initial concentration of the adsorbate, adsorbent dosage, and temperature of the solution. Kinetic studies of the data showed that the adsorption follows the pseudo-second-order kinetic model. Thermodynamic parameters showed that adsorption on the surface of BWAC was feasible, spontaneous in nature, and exothermic between temperatures of 298 and 318 K. The equilibrium data better fitted the Freundlich isotherm model for studying the adsorption behavior of Hexavalent Chromium by BWAC. IR spectrum for loaded and unloaded BWAC was obtained using FT-IR spectrophotometer. Adsorption efficiency and capacity of Hexavalent Chromium were found to be 98.28% at pH 2 and 59.23 mg/g at 300 K. Tamirat Dula, Khalid Siraj, and Shimeles Addisu Kitte Copyright © 2014 Tamirat Dula et al. All rights reserved. Gas Chromatography Mass Spectrometry Identification of Labile Radicals Formed during Pyrolysis of Catechool, Hydroquinone, and Phenol through Neutral Pyrolysis Product Mass Analysis Sun, 29 Dec 2013 08:39:44 +0000 Catechol, hydroquinone, and phenol are known to be environmental pollutants due to their ability to generate environmentally free radicals, which cause millions of deaths worldwide. Recently, efforts have been done to precisely identify the origin and the nature of those free radicals employing EPR-LTMI technique. All the three precursors generate cyclopentadienyl radical as major pyrolysis products and phenoxyl radical as both pyrolysis and photolysis products which were obtained from phenol; ortho-semiquinone and para-semiquinone were seen, respectively, from the pyrolysis of catechol and hydroquinone. However, it has been suspected that the solely use of the EPR-LTMI did not allow the isolation of the more labile radicals that is supposedly terminated by radical-radical or radical-surface interaction. The present study reports the gas chromatography mass analysis of the pyrolysis products from catechol, hydroquinone, and phenol. Naphthalene , indene, and hydroxyindene were observed as the pyrolysis products of hydroquinone, while fluorene, 1H-indenol and its isomer 1H-inden-1-one 2,3 dihydro, acenaphthylene, benzofuran-7-methyl, and benzofuran-2-methyl were observed as pyrolysis products of catechol. Dibenzo dioxin and dibenzo furan were observed from pyrolysis of catechol and hydroquinone. Those products result from the combination of radicals such as cyclopentadienyl, para-semiquinone, ortho-semiquinone, hydroxyl-cyclohexadienyl, phenoxyl, and most importantly Hydroxycyclopentadienyl which was not identified by EPR-LTMI. Julien Adounkpe, Martin Aina, Daouda Mama, and Brice Sinsin Copyright © 2013 Julien Adounkpe et al. All rights reserved. Hydrocarbons Migration through Groundwater Convergence toward Saline Depressions: A Case Study, Sidi El Hani Discharge Playa, Tunisian Sahel Wed, 30 Oct 2013 10:59:22 +0000 This paper aims to provide proofs of hydrocarbons migration from petroleum reservoirs towards the surface of discharge playas. This is a case study of the discharge playa of Sidi El Hani, eastern Tunisia. The geochemistry of water of some hydrological drills in the Sahel area and of water from the discharge playa proves relatedness between the deep aquifer and the water of the discharge playa. Thus, the hydrology is now more than likely converging from the subsurface. This convergence may be an agent of transport of hydrocarbons. Concerning the organic matter within the discharge playa, high percentages of different fractions seem abnormal in such a saline context. This maturated organic matter should be viewed in the widest context of a multidisciplinary study taking into account the presence of petroleum potentials in the subsurface, the converging hydrogeology, and the tectonised region. The high percentage of Aromatic Polycyclic Hydrocarbon (APH) may be the result of hydrocarbons migration rather than anthropogenic pollution. As for the reinterpretation of previous works about the organic matter in playas done in sebkha Moknine, the contaminated organic matter, which was interpreted as a human induced activity, may have another origin from a reservoir located in the subsurface of the Sahel area. Elhoucine Essefi, Mohamed Ali Tagorti, Jamel Touir, and Chokri Yaich Copyright © 2013 Elhoucine Essefi et al. All rights reserved. Removal of Methyl Violet 2B from Aqueous Solution Using Casuarina equisetifolia Needle Tue, 08 Oct 2013 16:03:47 +0000 One of the major contaminants of water bodies is dye pollutants that come from textile, paper, and leather industries. In this study, Casuarina equisetifolia needle (CEN) is used to remove methyl violet 2B (MV) from aqueous solutions. Batch experiments were done to investigate the contact time, effect of pH, initial dye concentrations, and temperature. Langmuir and Freundlich isotherm models were used to describe the interaction between the adsorbate and adsorbent. The sorption mechanism was described using Lagergren 1st order, pseudo 2nd order, and Weber-Morris intraparticle diffusion models. FTIR spectroscopy was used to analyze the functional groups of CEN before and after sorption with MV. Optimal conditions were found to be at room temperature with 2 h contact time and no pH adjustment was needed. Experimental data was best fitted onto Langmuir model with maximum adsorption capacity of 164.99 mg/g, while pseudo 2nd order best described the experimental data for the kinetics study. Thermodynamic parameters such as change in Gibbs free energy (), enthalpy (), and entropy () were also investigated. Muhammad Khairud Dahri, Muhammad Raziq Rahimi Kooh, and Linda B. L. Lim Copyright © 2013 Muhammad Khairud Dahri et al. All rights reserved. Assessment of Heavy Metals Concentration in Arsenic Contaminated Groundwater of the Chaco Plain, Argentina Tue, 17 Sep 2013 13:20:37 +0000 The occurrence and distribution of arsenic and 23 other trace elements have been investigated in groundwater from Comandante Fernández Department in the Central region of Chaco Province, Northern Argentine. The arsenic concentrations samples ranged between 0.7 to 1990 µg L−1; 91% () exceeds the 10 µg L−1 World Health Organization (WHO) provisional standard limits for drinking water. Fluorine was detected in 31% of groundwater samples. Furthermore, there was found a significant correlation between As and F (), indicating an association in the prevalence of both elements. In addition, about 78%, 31%, 16%, 13%, and 4.5% of groundwater samples had, respectively, B, Fe, Al, Mn, and Sb exceeding Código Alimentario Argentino (CAA) guideline values. In contrast of the previously values descript, the corresponding to Cr, Be, Ni, Pb, Ag, Se, and Zn were found below the quantification limit. The presence of As and trace elements in groundwater represents an important issue because it can cause a public health problem. M. Cecilia Giménez, Patricia S. Blanes, Edgar E. Buchhamer, Rosa M. Osicka, Yamila Morisio, and Silvia S. Farías Copyright © 2013 M. Cecilia Giménez et al. All rights reserved. Evaluation of Preoxidized SUS304 as a Catalyst for Hydrocarbon Reforming Sun, 01 Sep 2013 08:45:42 +0000 The feasibility of oxidation pretreated SUS304 alloy tube as a hydrocarbon reforming catalyst was investigated. It was hypothesized that preoxidation resulted in the dispersion of the active component and the formation of mixed metal oxides on the surface of the alloy which consequently rendered the alloy tube catalytically active towards reforming reaction. Oxidation pretreatment was done in O2 at 1000°C for 2 hours followed by a catalytic evaluation at 730°C for 2 hours. Tetradecane was used as a model compound for steam, partial oxidation, and CO2 reforming experiments. According to the collected XRD pattern, α-Fe2O3 and Cr2O3 were formed after oxidation pretreatment. In addition, SEM-EDX analysis showed a very rough surface composed of oxygen, chromium, iron, and nickel. Catalytic evaluation of the sample displayed activity towards partial oxidation and CO2 reforming which led to the conclusion that oxidation pretreated SUS304 alloy tube has a potential as a catalyst for partial oxidation and CO2 reforming of hydrocarbons. However, the varying activity observed suggested that each reforming reaction requires a specific formulation and morphology. S. R. de la Rama, S. Kawai, H. Yamada, and T. Tagawa Copyright © 2013 S. R. de la Rama et al. All rights reserved. Batch Adsorption of Maxilon Red GRL from Aqueous Solution by Natural Sugarcane Stalks Powder Thu, 01 Aug 2013 11:01:38 +0000 Sugarcane stalks powder was tested for its efficiency of removing a textile dye Maxilon Red GRL from aqueous solution. Different parameters affecting dye removal efficiency were studied. These parameters include contact time, initial dye concentration, adsorbent dose, ionic strength, pH, and temperature. Langmuir and Freundlich isotherm models were applied to the equilibrium data. The data fitted well with the Langmuir isotherm (). The maximum monolayer adsorption capacity () was found to be 20.96 mg/g at an initial pH of 7.2. The temperature variation study showed that dye adsorption is exothermic and spontaneous with increased randomness at the solid solution interface. The results indicated that sugarcane stalks could be an alternative for more costly adsorbents used for dye removal. The kinetic of the adsorption process followed the pseudo second-order kinetics model. Gamal Owes El-Sayed, Talaat Younis Mohammed, and Ashraf Abd-Allah Salama Copyright © 2013 Gamal Owes El-Sayed et al. All rights reserved. Closed Anaerobic Biotransformation Products of Organoarsenic Compounds in Fucus distichus Sun, 14 Jul 2013 08:06:54 +0000 The closed anaerobic decomposition extracts of Fucus distichus incubated with seawater and sediment, and without sediment as control, were subjected to extractions and isolation on Sephadex LH 20 and Cellulose Thin Layer Chromatography. The decomposition extracts and isolates were analyzed by using both the Hydride Generation Gas Chromatography Atomic Absorption Spectrometry (HG-GC-AAS) and High Performance Liquid Chromatography Inductively Coupled Plasma Mass Spectrometry (HPLC-ICPMS) to identify the arsenic species in the equilibrium mixtures of the seaweed and filtrates separately. In the methanol seaweed extract, equilibrium mixture of arsenosugars (AS) AS1 and AS2 and their biotransformation products of dimethylarsinoylethanol (DMAE) and dimethylarsinic acid (DMAA) were identified. In the methanol filtrate extract of the mixture, only DMAE and DMAA were identified. However, in the control methanol filtrate extract five organoarsenic species, AS1 and AS2, one unidentified hidden organoarsenic species, DMAE and DMAA were identified in the equilibrium mixture. This result confirmed that the hidden organoarsenic species in Fucus distichus, AS1 and AS2, and an unidentified organoarsenic compounds are biotransformed to only DMAE and DMAA under an anaerobic condition. This also suggests that DMAE and DMAA are strong intermediate candidates for the generation of arsenobetaine, from arsenoribosides in the marine food webs. Abiodun A. Ojo and Amos Onasanya Copyright © 2013 Abiodun A. Ojo and Amos Onasanya. All rights reserved. Electrochemical Oxidation of Ethinylestradiol on a Commercial Ti/Ru0.3 Ti0.7O2 DSA Electrode Tue, 02 Jul 2013 10:24:23 +0000 The electrochemical oxidation of the hormone ethinylestradiol in an aqueous-methanolic medium by the application of a constant current of 40 mA cm−2 in a flow cell with a commercial Ti/Ru0.3 Ti0.7O2 electrode was evaluated. The effect caused by the use of NaCl as a support electrolyte was also investigated. Hence, HPLC-UV analyses revealed that ethinylestradiol was almost totally consumed after a 60 min reaction time in the presence of NaCl. Conversely, much lower degradation rates were obtained when NaCl was not employed. Moreover, direct infusion ESI-MS and GC-MS analysis revealed that apparently no degradation products had been formed under these conditions. Hence, this study clearly demonstrated that such electrochemical treatment can be efficiently used to promote the complete degradation (and probably mineralization) of the hormone ethinylestradiol. Karla M. Vieira, Clésia C. Nascentes, Artur J. Motheo, and Rodinei Augusti Copyright © 2013 Karla M. Vieira et al. All rights reserved. Uptake Capacity of Pb2+ by Sulphonated Biomass of Cicer arietinum: Batch Studies Mon, 17 Jun 2013 08:38:56 +0000 Fundamental investigation on the removal of heavy metal Pb2+ from aqueous solutions by sulphonated biomass (S-III) of Cicer arietinum is conducted in batch mode. The effect of different parameters such as contact time, sorbent dose, pH and temperature has been studied. Adsorption kinetic modeling data were found. The kinetics of biosorption results shows that sorption process is well explained by pseudo-second-order model with determination coefficients 0.998 for S-III under all experimental conditions. The sorption mechanism was determined by Weber and Morris intraparticle diffusion model. Thermodynamic parameters, namely, and G,have also been calculated to determine the spontaneity of the process. A. A. Kale Copyright © 2013 A. A. Kale. All rights reserved. Emissions of SO3 from a Coal-Fired Fluidized Bed under Normal and Staged Combustion Sun, 12 May 2013 15:06:49 +0000 This paper reports the measurements of SO3 emissions with and without limestone under unstaged and staged fluidized-bed combustion, carried out on a  m2 and 2 m high stainless-steel combustor at atmospheric pressure. The secondary air was injected 100 cm above the distributor. SO3 emissions were monitored for staging levels of 85 : 15, 70 : 30, and 60 : 40, equivalent to a primary air/coal ratio (PACR) of ~0.86, 0.75, and 0.67. Experiments were carried out at 0%–60% excess air level, 1-2 m/s fluidizing velocity, 800–850°C bed temperature, and 20–30 cm bed height. During unstaged combustion runs, SO3 emissions were monitored for a wide range of Ca/S ratios from 0.5 to 13. However, for the staged combustion runs, the Ca/S ratio was fixed at 3. SO3 was retained to a lesser extent than SO2, suggesting that SO2 reacts preferentially with CaO and that SO3 is involved in the sulphation process to a lesser degree. The SO3 emissions were found to be affected by excess air, whereas the fluidizing velocity and bed temperature had little effect. SO3 was depressed on the addition of limestone during both the staged and unstaged operations, and the extent of the reduction was higher under staged combustion. Wasi Z. Khan, Bernard M. Gibbs, and Assem Ayaganova Copyright © 2013 Wasi Z. Khan et al. All rights reserved. Photocatalysis of the Organophosphorus Fenamiphos: Insight into the Degradation Mechanism Thu, 02 May 2013 16:03:00 +0000 The photocatalytic degradation of the organophosphorus fenamiphos (FN) was studied using titanium dioxide as a photocatalyst and 365 nm as an excitation wavelength. Under our experimental conditions and in aerated solutions, the irradiation in the presence of TiO2 P25 (1.0 g L−1) permitted the evaluation of the half lifetime to 9.5 minutes. Laser flash photolysis experiments showed the formation of an initial species owing to the attack of the hydroxyl radical on FN. It was identified as the adduct -FN. The second order rate constant for its formation was evaluated to  moL−1 L s−1. All the products are formed via the formation of such transient intermediate. They were identified by means of HPLC/MS using electrospray in positive mode (). Two main processes are responsible for FN photocatalytic transformation: (i) hydroxylation on the aromatic structure and (ii) the scission of the C–O bond. A mechanistic scheme was proposed for the photocatalytic process of FN using titanium dioxide. An efficient mineralization was observed within 24 hours by using a suntest setup. H. Mountacer, S. M. Nemmaoui, S. Rafqah, G. Voyard, and M. Sarakha Copyright © 2013 H. Mountacer et al. All rights reserved. Sorption of Tetracycline, Oxytetracycline, and Chlortetracycline in Illite and Kaolinite Suspensions Mon, 15 Apr 2013 09:05:18 +0000 The sorption interaction of three widely used tetracycline antibiotics, namely, tetracycline, chlortetracycline, and oxytetracycline, under various conditions of time, pH, temperature, ionic strength, and exchangeable cations on illites and kaolinites was examined. First-order reaction indicated diffusion-controlled adsorption, maximum adsorption occurring at pH values of 3.5, 3, and 4 for tetracycline, oxytetracycline, and chlortetracycline, respectively. Adsorption isotherms of “L” type showed that the adsorption of antibiotics was in the order of chlortetracycline > oxytetracycline > tetracycline. Adsorption was maximum for Al-saturated complexes and followed the order of Al- > Na- > K- Ca. The adsorption varied inversely with changes in temperature and ionic strength up to 0.6 after which it became constant. Free energy changes (ΔG) were negative signifying a spontaneous reaction; the values of ΔG suggest a partial physical adsorption. Enthalpy changes showed that the process is exothermic. The positive values of entropy change suggest that adsorption of tetracyclines molecules is in disordered arrangement on clay surfaces. The data of these parameters with IR and X-ray studies revealed the existence of protonation and/or coordination between exchangeable cation and oxygen of >C=O group of antibiotics. The amount of cations desorbed indicated that cation exchange phenomena played an important role during adsorption. O. P. Bansal Copyright © 2013 O. P. Bansal. All rights reserved.