Application of nano zinc oxide (nZnO) for the removal of triphenyltin chloride (TPT) from dockyard wastewater

The use of triphenyltin chloride (TPT), a persistent organic pollutant, as a biocide has led to serious contamination of the marine environment. The potential of nano zinc oxide (nZnO) for the removal of TPT from contaminated dockyard wastewater was investigated. The adsorption of TPT onto nZnO has been found to depend on the adsorbent dose, contact time, pH, stirring speed, and temperature. Equilibrium data fitted well with the Freundlich model and the experiments showed that 97.0% TPT removal was achieved by treating 0.643 mg·l-1 TPT contaminated dockyard wastewater with 0.5 g nZnO at optimal conditions. The kinetic data for the adsorption process obeyed a pseudo second-order kinetic model, suggesting that the adsorption process is chemisorption. The nZnO investigated in this study showed good potential for the removal of TPT from contaminated dockyard wastewater systems

Occurrence of PAHs in water samples of the Diep River, South Africa

Occurrence of polycyclic aromatic hydrocarbons (PAHs) in freshwater may aggravate the water crisis currently being experienced in the Western Cape Province of South Africa. However, there is dearth of data on the levels of PAHs, which is necessary for effective assessment of water quality as well as remediation strategies. This study therefore assessed levels of PAHs in the Diep River freshwater system of Western Cape Province, South Africa. A liquid-liquid extraction solid-phase extraction gas chromatography flame ionisation detection (LLE-SPEGC-FID) method was developed to simultaneously determine the 16 United States Environmental Protection Agency (USEPA) listed priority PAHs in water samples. The SPE-GC-FID method allowed an acceptable linearity (R2 > 0.999) within the calibration range of 1 to 50 μg/mL. Instrument detection limits ranged between 0.02 and 0.04 μg/mL and instrument quantification limits between 0.06 and 0.13 μg/mL. Recovery study results were also acceptable (83.69–96.44%) except for naphthalene, which had recovery of 60.05% in spiked water matrix. The seasonal averages of individual PAH detected at the studied sites ranged between not detected (nd) and 72.38 ± 9.58 μg/L in water samples.Keywords: PAHs, Diep River, GC-FID, freshwate

Determination of oxalic acid in vegetables

Oxalate is a common constituent of plants, and several species, including some crop plants, accumulate high levels of this C2 dicarboxylic acid anion. Depending upon species, oxalate accumulates primarily as soluble oxalate, insoluble calcium oxalate, or a combination of these two forms. From an agricultural point of view, oxalate is of concern because of health-related hazards due to high oxalate levels in food and animal feed (Libert and Franceschi 1987). Reviews on oxalate in plants by Oke (1969) (nutritive aspects), Hodgkinson (1977), and Franceschi and Horner (1980) (calcium oxalate in plants) have appeared. Several other works have been reported on antinutritive effects and toxicity of dietary oxalate (Grott 1942; Wittwer et al. 1947; Oke 1969; James 1970; Sing et al. 1972; Chadwick et al. 1973; Hodgkinson 1978; Swartzman et al. 1978; van Campen and Welch 1980; Gillooly et al. 1983; Kelsay 1981, 1985)

FTIR Spectroelectrochemical Studies on [Ru3(CO)12] and fac-[Re(Cl)(CO)3(4bzpy)2] (4bzpy = 4-benzoylpyridine)

Incorporation of wire mesh platinum electrodes into a standard infrared solution cell yielded an inexpensive and easy to maintain optically transparent thin layer electrochemical (OTTLE) cell, well suited for IR analysis of species with half-lives of seconds to minutes. As test bed, two reactions were investigated, which are discussed in the literature: (i) for [Ru3(CO)12] evidence was found for at least partial reversibility in the two-electron reduction process to [Ru3(CO)11]2-, and (ii) for fac-[Re(Cl)(CO)3(4bzpy)2] (4bzpy = 4-benzoylpyridine) additional information concerning the two-step electron reduction of the two benzoylpyridine ligands (again partially reversible) could be obtaine

Phthalate esters in rivers of the greater Manchester area, U.K.

Waters from the Rivers Irwell and Etherow and from the Prestwich sewage treatment plant effluent, Manchester, U.K., were analyzed for the presence of phthalate esters using computer-assisted gas chromatography-mass spectrometry (GC-MS). Extraction was with CHCl3. Liquid chromatography clean-up was used for compound separation. Several phthalate esters, i.e. diethyl (DEP), butyl-2-monopropyl (BMP), di-n-butyl (DBP), di-2-ethylhexyl (DEHP) and di-iso-octyl (DIOP), were found to be present at 0.4–33.5 μg l−1. A study on uncontaminated waters was undertaken to establish blank levels

Abatement of Cr6+ and Pb2+ from aqueous matrices using sugarcane biomass

Abatement of Cr6+ and Pb2+ from aqueous matrices using sugarcane biomass 4th International Ecosummit, Columbus, OH, 30 September-5 October 201

Zinc abatement from simulated and industrial wastewaters using sugarcane biomass

The use of heavy metals and their compounds in industrial applications has resulted in their occurrence in various environmental media including water bodies. Conventional methods of heavy metal removal from wastewaters are very expensive, when available, especially in developing countries. This study therefore assessed the potential of sugarcane biomass to remove zinc from standard solutions and industrial (paint and textile) wastewaters. Parameters studied include contact time, biomass weight, metal concentration, pH, agitation, temperature and particle size. Physico-chemical characteristics of biomass were also studied. Adsorption of zinc increased with increases in contact time, biomass weight, pH and agitation speed, while adsorption decreased with increasing particle size and for temperatures above 50o C. Sugarcane biomass was responsible for over 90% adsorption of Zn2+ in both effluents. Under conditions of agitation, 100% adsorption was achieved. Percentage ash, particle density, cation exchange capacity (CEC) and porosity are important physico-chemical properties which influenced Zn2+ adsorption. Percentage ash and CEC are positively correlated to percentage adsorption while particle density and porosity are negatively correlated. Percentage desorption was over 90 for both effluents. Sugarcane biomass is therefore a potential alternative to expensive synthetic resins. Its biodegradability makes disposal environmentally friendly. However, there is the need to further study the biomass in flow-through systems for industrial applicability.International Foundation for Science (IFS), Sweden, through Research Grant No. W/4264-

Pollution assessment in the Keiskamma River and in the impoundment downstream

The Keiskamma River and the impoundment, downstream were characterised over a one-year period by using standard physicochemical methods to assess their present qualities. The pH levels are normal in the river and in the impoundment but turbidity values and the levels of electrical conductivity are high in both water systems. Also, the nutrient levels in both systems are eutrophic. The DO and BOD levels exceeded EU guideline values for the protection of the aquatic ecosystem. The Keiskammahoek Sewage Treatment Plant (KSTP) was identified as a pollution point source into the receiving river and the impoundment. Its treatment performance was investigated. Significant pollution of the river and the impoundment from the KSTP was indicated for electrical conductivity, nutrients and oxygen-demanding substances.NR

Physicochemical properties of some underexploited and nonconventional oilseeds

Six nonconventional oilseeds, Bauhinia monandra, Bauhinia refescens, Caesalpinia pulcherrima, Cyperus esculentus, Hildergadia bateri, and Garcenia kola, were analyzed for their proximate composition, minerals, fatty acids, iodine values, acid values, saponification values, viscosities, refractive indexes, and specific gravity values. Their moisture content ranged from 3.8 to 9.8%. The crude protein values varied between 0.2% in G. kola and 26.6% in C. pulcherrima. The crude oil content ranged from 0.2% in G. kola to 30.8% in C. rufescense. The oilseeds were generally high in potassium (265 f 2.1 to 1050 f 4.2%) and sodium (100 f 1.4 to 260 f 1.4%). The fatty acid composition ranged from to Clg, including unsaturated Clg:~, C~W, and c18:3. The unsaturated fatty acids were predominant. Iodine values varied between 82.4 f 3.04 in H. bateri and 123.0 f 3.55 in C. pulcherrima. The saponification values ranged from 165.8 f 0.05 in H. bateri to 246.8 k 0.47 in C. pulcherrima. Acid values varied between 2.3 f 0.01 and 6.5 f 0.02 in the oilseeds. The viscosity values were low and, at 30 "C, values ranged from 13.18 f 0.03 cSt in B. monandra to 27.54 f 0.04 cSt in B. rufescens. The refractive indices and specific gravity values show littlevariation in the samples

Polycyclic aromatic hydrocarbons (pahs) in food and environmental samples: an overview

Polycyclic aromatic hydrocarbons (PAHs) have been widely reported as a class of ubiquitous chemicals in different matrices. Health implications of these pollutants include carcinogenicity and mutagenicity amongst others. The need for effective measurement techniques of these compounds therefore becomes imperative. This paper reviews sources of PAHs into the environment, exposure routes and effects on humans. Furthermore, an overview of different measurement techniques in environmental and food samples is also presented. Extraction methods that have been applied for PAHs quantification include solidphase extraction (SPE), solid-phase microextraction (SPME), stir bar sorptive extraction (SBSE), liquid-phase microextraction (LPME), liquid-liquid extraction (LLE), accelerated solvent extraction (ASE) and solid-liquid extraction. Most commonly used analytical methods are gas chromatography-mass spectrometry (GC/MS), gas chromatography- flame ionization detection (GC/FID), high performance liquid chromatography-fluorescence detection (HPLC/FD) and high performance liquid chromatography- ultra violet detection (HPLC/UV). Levels reported in different media suggest global need for PAHs monitoring in foods and environmental samples. KEYWORDS: Extraction, analysis, polycyclic aromatic hydrocarbons, food, soil and water