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Iron-oxide nanoadsorbents are attractive for wastewater treatment for two important reasons. First, nanoadsorbents can remove contaminants from wastewater rapidly. Second, iron oxide nanoadsorbents can be employed as catalysts for the decomposition of contaminants and thus eliminate sludge formation. This article investigates the use of iron-oxide nanoadsorbents to remove contaminants from wastewater. A later paper considers their use as catalysts for decomposition.In this study, goethite (a type of iron oxide) nanoparticles was employed for the removal of methylene blue from an aqueous solution, using a batch-adsorption technique. Effects of contact time, initial concentration of methylene blue, temperature, and solution pH on the adsorbed amount of methylene blue were investigated. Adsorption was rapid, as equilibrium was achieved within 20 minutes. An external mass transfer model fit adsorption kinetic results well and provided reasonable overall volumetric mass transfer coefficients. Increases in initial concentration, temperature, and pH favored the adsorption of methylene blue. Adsorption data fit both the Langmuir and Freundlich isotherm models well, with the better fit to the Langmuir model. Thermodynamic studies confirmed that the adsorption reaction was spontaneous and endothermic in nature.

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Several methods are currently used to track the bio-component of co-processed fuels including energy/mass balance, yield methods and radiocarbon techniques. The methods used to track or estimate the bio-component of fuels produced when bio and fossil feedstocks are processed together (co-processed) in oil refineries were analysed in detail, together with their advantages and disadvantages. Some methods, such as radiocarbon methods that allow the direct measurement of the bio-content in a fuel, have been criticised due to low accuracy at low blends. However, these reservations have tended to misinterpret the options available for carbon dating and to discount recent improvements in these tests. As much higher co-pressing mixtures are anticipated if published national decarbonisation targets are to be achieved, any challenges at very low co-processing ratios affecting the accuracy of the radiocarbon methods should not be an issue. Energy/mass balance and yield methods might be supplemented with carbon-tracking to determine the real the biogenic content.

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