A comparison study of cleanup techniques for oil spill treatment using magnetic nanomaterials.

Magnetic nanoparticles have been successfully used to recovery oil from oil spilled on water. Two different methods, floating and vortex, were employed to promote the interaction of four oil samples with different API (e.g., 10, 20, 28 and 45) spilled on seawater and deionized water with three magnetic materials, namely: magnetite nanoparticles (N); magnetic nanocomposites of yeast biomass provided by ethanol industry (Y); and magnetic nanocomposites of cork powder (C). The magnetic nanomaterials exposed to oil on water were taking out by a neodymium magnet, and the oil recoveries were determined by gravimetric analysis before and after lyophilization. The lyophilization was determinant to guarantee the accuracy of the experiments, and without this step, the masses of oil recovered would be overestimated due to the drag of water during the oil and magnetic material removal process. Three main factors, API, contact method and magnetic material, and two interactions (i.e., API × contact method, and contact method × magnetic material) presented a statistically significant effect on oil recovery. It was observed that oil recovery increases as API decreases, and it was possible to establish a model to predict the amount of recovered oil according to this effect. Higher oil recoveries were also obtained by magnetic nanocomposites of yeast biomass (Y), regardless of the contact method and type of water, recoveries of 23% and 100% for 45 and 10 API, respectively, employing around 20 mg of Y on 300 mg of spilled oil. These percentages correspond to 0.29 ±â€¯0.01 kg/kg and 15.98 kg/kg of recovering oil by the magnetic procedure. The increase of mass of magnetic material improved the recovery of oils with higher APIs. The reusability of the spent materials presents potential for its application in oil spill cleaning technologies.

Correction of iron interface in the spectrophotometric flow injection catalytic determination of molybdenum in plants.

Iron interference in the spectrophotometric catalytic determination of molybdenum based on the iodide-hydrogen peroxide reaction can be corrected by using sulphosalicylic acid as masking and color-forming reagent. The catalytic influence of iron ions is circumvented to the extent of about 90% and correction of any remaining iron ions is possible by monitoring the colored iron(III)-salicylate complex at 490 nm. In this way, iron is also determined. With the proposed system, molybdenum can be determined in plant and food digests within the 0-100 mug Mo 1(-1) range in the presence of up to 25 mg Fe 1(-1), at a sampling rate of about 50 determinations h(-1). The relative standard deviation of 10 consecutive measurements was estimated as < 2%. Results for samples were comparable with those obtained by graphite furnace atomic absorption spectrometry. In addition, recoveries within the range 94-100% were calculated.

Assessing metal sorption on the marine alga Pilayella littoralis.

Increasing interest in the development of biological materials for metal sorption led us to investigate the brown marine alga, Pilayella littoralis, as a biological sorbent. This work focuses on the harvest, preparation and evaluation of P. littoralis from Nahant beaches for use as a metal biosorbent. This biomass was used in batch tests with synthetic solutions. Its metal uptake properties, including metal binding capacity, the pH dependence of metal uptake and the kinetics of metal sorption, were investigated. Most metal sorption occurred within the first 5 min of exposure and the metals were optimally bound to the algae at pH 5.5. The algal binding capacities for Al(III), Cd(II), Co(II), Cr(VI), Cu(II), Fe(III), Ni(II) and Zn(II), were 2,000, 430, 560, 90, 850, 700, 390 and 450 micromol g(-1) of dried biomass, respectively. Metals were desorbed with 0.12 mol l(-1) HCl and determined by inductively coupled plasma atomic emission spectrometry (ICP-AES).

An attempt to correlate fat and protein content of biological samples with residual carbon after microwave-assisted digestion.

The residual carbon content of a variety of bovine-derived samples and forage was determined by inductively coupled plasma optical emission spectrometry with radial view configuration (ICP-OES) after microwave-assisted digestion under high pressure in a closed vessel. The original carbon concentration in the samples was determined by elemental analysis. The highest amount of original carbon content (64%) was found in viscera. After digestion, up to 75% of it was destroyed. Viscera presented the highest ether extract and blood exhibited a high crude protein content of up to 99%. The efficiency in destroying the organic matter in biological materials seemed to be related to their fat content and showed no significant difficulty for protein-rich samples. The correlation coefficient between the fat content of the samples and the residual carbon after acid decomposition was 0.9173 indicating a fair fit. However, no correlation was observed between % RC and the protein content.