Pedro Sergio Fadini

Using the Response Surface Methodology (RSM) and Rotational Central Composite Design (RCCD), this study evaluated the removal of DCF under denitrifying conditions, with ethanol as cosubstrate, in batch reactors, being 1 L Erlenmeyer flasks (330 mL of reactional volume) containing Dofing medium and kept under agitation at 130 rpm and incubated at mesophilic temperature (30 °C). It considered the individual and multiple effects of the variables: nitrate (130 - 230 mg NO₃^- L^-1), DCF (60 - 100 µg DCF L^-1) and ethanol (130 - 230 mg EtOH L^-1). The highest drug removal efficiency (17.5%) and total nitrate removal were obtained at 176.6 ± 4.3 mg NO₃^- L^-1, 76.8 ± 3.7 µg DCF L^-1, and 180.0 ± 2.5 mg EtOH L^-1. Under such conditions, the addition of ethanol and nitrate was significant for the additional removal of diclofenac (p > 0.05). The prevalence of Rhodanobacter, Haliangium and Terrimonas in the inoculum biomass (activated sludge systems) was identified through the 16S rRNA gene sequencing. The potential of these genera to remove nitrate and degrade diclofenac was inferred, and the main enzymes potentially involved in this process were α-methylacyl-CoA racemase, long-chain fatty acid-CoA ligase, catalases and pseudoperoxidases. GRAPHICAL ABSTRACT

SUSTAINABILITY IN PHOSPHORUS USE: A BIBLIOGRAPHIC REVIEW FOCUSING ON THE CURRENT SITUATION IN THE STATE OF SÃO PAULO, BRAZIL. Phosphorus is a non-renewable element essential for the existence of life and also for food security. This resource has the property of limiting plant growth, becoming a fundamental part of agricultural production. On the other hand, when this element is present in high concentrations in aquatic environments, it can start a phenomenon called eutrophication, which causes a series of changes in biological succession processes and strongly negative impacts on species’ biodiversity and wealth. In this context, this work aimed, from an extensive bibliographical review, to gather strategic and essential information related to phosphorus sustainability, provoking a reflection regarding scenarios that involve this indispensable nutrient, focusing on the current situation of the State of São Paulo, Brazil, an important case study, both for the Brazilian and international scenario, by a gathering of data on the current situation of two of the main watersheds in the corresponding region. Relevant technologies used for phosphorus removal in eutrophicated environments are also addressed. Finally, the possibility of reusing the nutrients present in eutrophicated water bodies as an alternative source of phosphate fertilizer for agriculture is demonstrated.

A simple and reproducible method was developed and validated for simultaneous quantification of the pesticide fipronil and its intermediates fipronil desulfinyl, fipronil sulfone and fipronil sulfide, in soil. The analytes were extracted by ultrasonic bath and the ratio of solvents (hexane/acetone), number and time of cycles were optimized by Box–Behnken design with a triplicate central point. The optimal extraction conditions were achieved through a response surface analysis. The clean-up step was conducted by cartridges of solid phase extraction (SPE) containing silica (Florisil®) and aluminum oxide. Gas chromatography with electron capture detection (GC-ECD) was employed for separating fipronil and its intermediates with a suitable resolution and runtime of 20 minutes. The best quantification was achieved with 1 : 1 (v/v) acetone/hexane and 2 ultrasound cycles of 15 minutes each. The recovery values were between 81 to 108%, with relative standard deviation (RSD) lower than 6%, with no effect of the used matrix. Analytical curves presented regression coefficients values above 0.9908 for a concentration range from 0.005 to 0.6 μg g⁻¹. Limits of detection (LOD) from 0.002 to 0.006 μg g⁻¹ and limits of quantification (LOQ) from 0.006 to 0.020 μg g⁻¹ were reached for all analytes. This method can be used to monitor and quantify fipronil and its intermediates in soil.

The present work reports the degradation of 4-nitrophenol using BiVO₄/CuO hybrid material synthesized by the precipitation of BiVO₄ in the presence of CuO. Morphological and structural characterizations were performed using X-ray diffraction and scanning electronic microscopy coupled to energy dispersive X-ray spectroscopy. Through the calculation of the Kubelka–Munk function applied to diffuse reflectance spectrophotometry data, the hybrid material presented absorption edge of 1.85 eV. The formation of p-n heterojunction between BiVO₄ and CuO renders the hybrid material suitable for the construction of a photoanode employed in hydroxyl radical generation. UV–vis spectrophotometry and high-performance liquid chromatography experiments were performed in order to monitor the degradation of 4-nitrophenol and the formation of secondary products. Additional information regarding the hybrid material was obtained through ion chromatography and total organic carbon analyses. The application of BiVO₄/CuO-based photocatalyzer led to a 50.2% decrease in total organic carbon after the degradation of 4-nitrophenol. Based on the results obtained in the study, BiVO₄/CuO has proved to be a promising material suitable for the removal of recalcitrant compounds in water treatment plants.

A wide range of anthropogenic activities have caused various problems to the aquatic environment, leading to economic, social and environmental losses. The use of materials for the recovery of water quality is very important due to the water scarcity scenario present in different parts of the world. The use of sawdust as an organic adsorbent for phosphorus removal in eutrophic environments attempts to address both water quality preservation and possible application of the organic adsorbent as fertilizer for agricultural practices. This will result in important contributions to the water and food security. In this work, we performed laboratory experiments to study phosphorus adsorption and to evaluate possible adsorption of metals and emerging contaminants by sawdust. The experiments were carried out in 36 microcosms (glass jars), using 50% of the flasks as treatments (containing bags with sawdust) and the rest of the flasks as control (water and sediment without sawdust). For future application of sawdust as a fertilizer it is important to be aware of the presence of possible pathogenic microorganisms, thus the presence of helminth eggs was determined in the sawdust. The results showed the tendency of phosphorus adsorption by the biosorbent; maximum adsorption occurred at 214 days (41 μg P g^‐1), after the phosphorus desorption occurred. Helminth eggs were not detected in any of the sawdust samples and the proposed biosorbent did not adsorb metal and emerging contaminants, this result is important for future use for fertilization purposes.