Environmental pollution by contaminants of emerging concern, among these various pesticides, has been a concern of environmentalists and scientists around the world. Thus, efforts to mitigate the impacts of these substances have been carried out, and the use of advanced oxidation processes, such as photocatalysis, is an alternative. This work sought to synthesize a composite photocatalyst based on iron oxides and titanium dioxide to assess its applicability in degrading the herbicide bentazon (BTZ) by a lamp that simulates the solar spectrum (visible, ultraviolet A and ultraviolet B) and sunlight. Photocatalytic degradation reached 51% in 120 min with a rate constant k = 0.0058 min-1 when a UV-Vis lamp of 300 W was used. The applicability was demonstrated under sunlight radiation, reaching 38% degradation of a bentazon solution (4.1 × 10-4 mol L-1) after 320 min. TiO2 and Fe2O3 were synthesized similarly but showed no degradation under the same conditions. Thus, Fe2O3-TiO2 is an inexpensive and non-toxic material capable of efficiently conducting the photocatalytic degradation of organic compounds, such as the bentazon herbicide.

A detailed study of the production of hydrogen and high added-value liquid products from the ethanol dehydrogenation reaction in the presence of sodium hydroxide (10% m m-1) was undertaken. Experiments were carried out in a batch reactor under different reaction conditions (temperature of 240 ºC and autogenous pressure between 45 and 72 bar), with analysis of the products obtained in the gas, liquid and solid fractions. The results showed that hydrogen was the major product formed in the gaseous fraction (maximum of 86.9%), while sodium acetate was the product in the solid fraction. Studies of the reaction mechanisms confirmed formation of the products identified in the gaseous and solid fractions. Mass spectrometry analyses of the liquid fractions revealed the presence of a series of compounds with molecular masses considerably higher than that of ethanol, which could be explained by the favoring of anionic polymerization reactions, under the experimental conditions employed.

Magnetic iron oxides are of great scientific and technological relevance. Therefore, herein, we report the research on developing methodologies for their sustainable and reproducible preparation. We discuss the synthesis of iron oxides involving citrus pectin as a source of energy (42 MJ kg-1) to promote the formation of the magnetic phases. The method involved two simple steps: gelation of the pectin (80 °C, 4 h) with iron nitrate nonahydrate [Fe(NO3)3.9H2O], and calcination (600 °C, 1 h). X-ray diffraction indicated the major formation of hematite (α-Fe2O3) and ferrite phases. Microscopy images show materials with an average size below 50 nm. Textural properties indicated pore sizes of 7-30 nm while magnetic measurements indicated the formation of soft and hard oxides (coercivity between 90 and 400 Oe) and high magnetization saturation (50 emu g-1).