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TiO(2) nanorods and ZrO(2)-modified TiO(2) nanocomposites have been prepared by hydrothermal synthesis and the deposition-precipitation method. Their sulfated products were tested as solid superacid catalysts for the esterification of levulinic acid which was used as a model bio-oil molecule. SEM and TEM characterization showed that TiO(2) nanorods with diameters ranging from 20 to 200 nm and with lengths of up to 5 μm were synthesized by a hydrothermal method at 180 °C. ZrO(2) nanoparticles with the diameters ranging from 10 to 20 nm were evenly deposited on TiO(2) nanorods. IR and XPS results suggested that sulfated ZrO(2)/TiO(2) nanocomposite has higher content of sulfate groups on the surface with a S/(Zr+Ti) ratio of 13.6% than sulfated TiO(2) nanorods with a S/Ti ratio of 4.9%. The HPLC results showed that sulfated ZrO(2)/TiO(2) nanocomposite have enhanced catalytic activity for esterification reaction between levulinic acid and ethanol compared to sulfated TiO(2) nanorods. The conversion of levulinic acid to ethyl levulinate can reach to 90.4% at the reaction temperature of 105 °C after 180 min.

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BACKGROUND: The adsorption of Cr(III) ions on various pig manure biochar (BC) samples was investigated to determine the effect of operating conditions (initial pH, sorbate and sorbent concentrations) on sorptive capacity. The BC samples with higher sorption capacity showed high surface area and were rich in alkaline metals whose concentration was measured by ICP-OES. RESULTS: For BCs from anaerobically and chemically pretreated feedstock greater pH changes and higher maximum capacitywere noted during Cr(III) adsorption than for BC from mechanically pretreated samples, due to a higher ion exchange capacity. The maximum Cr(III) uptake of 102 mg g -1 for the BC sample was achieved at c 0 = 300 mg dm -3 and pH = 5. It was also observed that the high ash content effectively lowered the surface area of BCs; however all BCs investigated contained a low level of toxic metals. CONCLUSIONS:The data indicate that both the technology used for separation of the manure and pyrolysis temperature had a significant influence on the physical and chemical properties of the BC and affected its sorption capacity. In addition, compared with other sorbents pig manure BC has one of the best Cr(III) sorption capacities.

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