Research Journal of Chemistry and Environment

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Research Journal of Chemistry and Environment

Antimicrobial Contaminant Behavior in Slow Sand Filter Schmutzdecke Mixed Cultures

Stephen J. Rooklidge, Joelle L. Bennett and Mark E. Dolan

Slow sand filtration is used in rural areas that may have source water contaminated by antimicrobials introduced from agricultural practices or wastewater effluent, and the waste biomass (schmutzdecke) is commonly applied to agricultural soils. This study investigated fluoroquinolone degradation in aerobic microcosms of bacteria cultured from schmutzdecke of a pilot slow sand filter previously exposed to antimicrobials for 60 days. Analysis of aqueous samples using a direct injection HPLC MS/MS method indicated half-lives of enrofloxacin, ciprofloxacin, and norfloxacin were 10.3, 12.3, and 23.5 days, respectively. Fluoroquinolone residues are expected to persist and accumulate in land-applied schmutzdecke in the same manner as land-applied human and animal waste. Antibacterial resistance development to seven antimicrobials was qualitatively examined by comparing zones of inhibition in a disk diffusion experiment using schmutzdecke cultures grown before and after the pilot filter injection period. Culture inhibition indicated exposure to antimicrobials may enhance resistance formation during a filtration period, and continued research investigating resistance transfer in biological filtration systems is warranted.

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Adsorption of Chromium VI from Aqueous Solution by Modified Cellulose Membranes

J. Ramírez-Flores, E. Rubio-Rosas and V. M. Castaño

Chromium VI was adsorbed by complex membranes from an aqueous solution at a concentration of 200 ppm. Three different types of supports were used for the membranes: nylon mesh, polyester membrane (as primary support) and polyester fabric, which were coated by cellulose-malic acid micro particles (with commercial fixer). The reaction between malic acid and Chromium VI was analyzed in aqueous solution with an excess of malic acid. A first order type of reaction was obtained, with a value of k´ of 0.00869 with 0.99768 correlation factor. The polyester fabric complex membrane showed 40 % higher flow rate than nylon mesh and polyester complex membranes, and a two-fold Cr VI adsorption capacity increase.

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Adsorption of Paraquat by Treated and Untreated Rice Husks Studied by Flow Injection-Analysis

I. A. Rahman, Y. Y. Sing, M. F. Bari and B. Saad

A flow injection analysis (FIA) was used for studies on the adsorption of paraquat on three types of rice husks, namely untreated- (RH), activated carbon derived from sodium hydroxide-treated (NAC) and phosphoric acid-treated (HPC) rice husks. They were studied under different experimental conditions of pH, adsorbent quantity, contact time and paraquat concentration. Equilibrium adsorption was reached within 5 minutes of contact with paraquat solution and maximum paraquat adsorption occured at pH > 6. The HPC exhibited the highest removal efficiency (~100 %) as compared to the NAC and RH adsorbent material. This high efficiency is probably due to the highly porous structure of the phosphoric acid-treated material. Modeling of the adsorption equilibrium suggested that the adsorption of paraquat fitted a Freundlich isotherm. The studies indicate that rice husks based materials can be used effectively for the removal of paraquat from water bodies.

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Thermal Properties, Environmental Deterioration and Applications of Macro-Defect-Free Cements

S. C. Mojumdar

Macro-Defect-Free (MDF) cements using the blends of sulfoaluminate ferrite belite (SAFB) clinkers and ordinary Portland cement (OPC) in mass ratio 85 : 15 and hydroxypropylmethyl cellulose (HPMC) or polyphosphates (poly-P) were subjected to various moist atmosphere to investigate their environmental deterioration. Their thermal decomposition studies were also carried out before and after moisture attack. The effect of individual relative humidity (RH) on moisture resistance of MDF cements is more intensive than the effects of composition of MDF cements or duration of the original MDF cements synthesis. There are three main temperature regions on TG curves of both series of MDF cement samples (before and after moisture attack). In the inter-phase section of MDF cements, the content of classical cement hydrates (CSH, gypsum, AFm and AFt phases) decomposing by 250 oC is increased, while the content of cross-links section and Ca(OH)2 with typical thermoanalytical traces in temperature range 250 - 550 oC remains almost identical before and after moisture attack. In the temperature range 550 - 800 oC, decomposition of CaCO3 occurred.

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Chemical and Pharmacological Characterization of Fire Coral from Eastern Red Sea

Sultan S. Al–Lihaibi

Two species of the fire coral, Millepora dichotoma and Millepora platytphylla, were found along the Eastern Red Sea Coast and collected. The chemical constituents as well as pharmacological screeing of the crude extracts were studied. Plant pigments content (chlorophyll a,b,c and phaeopigments) in the two species of fire coral were having more or less the same level (6.3 mgg-1 and 4.5 mgg-1) respectively. It was observed that the content of carbohydrate in both species was lower than lipid content, whereas protein was the highest component in the two species (3.5 mgg-1 and 3.4 mgg-1 respectively). The fatty acid methyl esters were analyzed by gas chromatography mass spectrometry (GC-MS), and it was observed that in both species, the saturated fatty acids were abundant (63.5% in M. dichotoma and 68.9% in M. platyphylla). Saturated fatty acids are indicative of dominant mode of action of autotrophic feeding. The residual material (mostly calcite in nature) in the two species was 57% and 53% respectively. The chemical composition of the M. dichotoma and M. platyphylla was compared with the obtained composition from the corals (other than fire corals) from the same area. It has been found that the fire coral have lower protein, lipid and carbohydrate contents compared to other corals. The preliminary screening; bactericidal and fungicidal activities of the crude extracts of M. dichotoma and M. platyphylla were tested. The bactericidal activity of the M. platyphylla was moderately active compared to the crude extracts of the M. dichotoma. Whereas no significance was observed on the phytotoxic bioassay tests of the crude extracts of the M. dichotoma and M. platyphylla.

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Comparison of Quantitative Methods in X-ray Analysis System (QXAS) Software Using IAEA Reference Materials (IAEA-359, Cabbage and IAEA-336, Lichen)

O.K. Owoade and F.S. Olise

For the comparison of quantitative methods in X-ray analysis system (QXAS) software and to determine under which conditions a particular quantitative method is applicable, samples of plant-based reference materials (IAEA-359, Cabbage and IAEA-336, Lichen) were analyzed by energy dispersive X-ray fluorescence (EDXRF) technique. Three methods, viz: Simple Quantitative (SQ), Emission-Transmission (ET) and Full-Fundamental Parameter (FFP) were used for the elemental quantifica-tion of the samples and the concentrations compared with the reference. The concentrations of trace elements measured in both samples were in good agreement with the certified values when correct dark matrix information was supplied for each sample analyzed. Significant deviations were observed for wrong dark matrix information inputs as well as total absence of dark matrix data. The FFP method was observed to give the best quantification results and is therefore recommended for application when dark matrix information of samples is known

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Particle Monitoring via an Ultrasonic Technique in Three-Phase Dense Silicon Slurries at Elevated Temperatures

Yee Soong and Isaac K. Gamwo

The objective of this investigation was to conduct a feasibility study into the use of an ultrasonic technique to monitor the concentration of silicon, up to 50 wt%, dispersed in a hydrocarbon solvent (Therminol 59) and nitrogen bubbles at elevated temperatures up to 250°C. We found that, as the solid concentration increases beyond 30 wt%, the trend of the amplitude signal reverses itself and exhibits a minimum. In addition, our data show that the transit time is nearly constant as the solid concentration increases up to 30 wt%, then decreases. This is probably due to the change of the dominant regime from viscous to inertia. These new findings are consistent at various temperatures and stirring speeds. The effects of particle size on the ultrasonic spectrum were significant and may be used to correlate the sizes of silicon metal at a given solids concentration. The results suggest possibilities for measuring the concentration of silicon metal and particle size distribution during operation of a three-phase slurry reactor at elevated reaction temperature and with Therminol.

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Activity of Amla or Phyllanthus Emblica as Coagulant and Coagulant aid for Water Purification

Parag Sadgir, S.L. Gargh, A.N. Patel, Ranu Bhandari and Kavita Sharma

Water is the most abundant compound on the surface of earth. Without it life on earth would cease to exist. In the process of developing a plant based substitute for water purification, many plants were screened for evaluation of their efficiency for turbidity removal. After literature review, Amla was tested as coagulant and coagulant aid in the water purification system and it was found effective.

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Agricultural Solid Waste for the Removal of Inorganics: Adsorption of Mercury (II) from Aqueous Solution by Tamarind Nut Carbon

A. Ramadevi and K.Srinivasan

Activated carbon prepared from bicarbonate- treated tamarind nut

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