By-products from the wax production process from carnauba palm (leaves), from the extraction of oil from macauba seeds (endocarp) and from pine nut production (shell) have been assessed for activated carbon production, using H3PO4 or CaCl2 for their chemical activation. The resulting activated charcoals have been thoroughly characterized by elemental and thermal analysis, X-ray diffraction, infrared spectroscopy, electron scanning microscopy and N2 adsorption behavior. Subsequently, their adsorption capacity for the removal of rhodamine B (RhB) from aqueous solutions has been evaluated by studying different parameters: contact time, pH, adsorbent dose, initial dye concentration and solution temperature. The adsorption of RhB followed Freundlich's model in all cases. Kinetic studies indicate that the pseudo-second order model can be used for describing the dynamics of the adsorption process. Thermodynamic parameters have also been evaluated, indicating its endothermic and spontaneous nature. Finally, a preliminary analysis of the impact of cellulose content in the carbon precursor materials has been conducted, by using a mixture of native cellulose with one of the lignocellulosic materials.

The synthesis and characterization of composites of oligomeric chitosan with propolis extract which allow the incorporation of a third component (silver nanoparticles) are reported, together with their application in aqueous or hydroalcoholic solutions with a view to the formation of adhesive substances or nanofilms for the protection of vineyards against harmful xylophagous fungi. The antimicrobial properties of the association of the two biological products or those resulting from the incorporation of silver nanoparticles (NPs) are studied and discussed. The efficacy of the chitosan oligomers/propolis/silver NPs ternary system is assessedin vitroforDiplodiafungi. A preliminary study on the convenience of replacing propolis with gentisic acid is also presented.

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Ammonia losses from manure pose serious problems for ecosystems and human and animal health. Gas-permeable membranes (GPMs) constitute a promising approach to address the challenge of reducing farm ammonia emissions and to attain the EU’s Clean Air Package goals. In this study, the effect of NH3-N concentration, membrane surface area, acid flux, and type of capture solution on ammonia recovery was investigated for a suspended GPM system through three experiments, in which ammonia was released from a synthetic solution (NH4Cl + NaHCO3 + allylthiourea). The effect of two surface areas (81.7 and 163.4 cm2) was first evaluated using three different synthetic N emitting concentrations (3000, 6000, and 12,000 mg NH3-N∙L−1) and keeping the flow of acidic solution (1N H2SO4) constant (0.8 L·h−1). A direct relationship was found between the amount of NH3 captured and the NH3-N concentration in the N-emitting solution, and between the amount of NH3 captured and the membrane surface area at the two lowest concentrations. Nonetheless, the use of a larger membrane surface barely improved ammonia capture at the highest concentration, pointing to the existence of other limiting factors. Hence, ammonia capture was then studied using different acid flow rates (0.8, 1.3, 1.6, and 2.1 L∙h−1) at a fixed N emitting concentration of 6000 mg NH3-N∙L−1 and a surface area of 122.5 cm2. A higher acid flow rate (0.8–2.1 L∙h−1) resulted in a substantial increase in ammonia absorption, from 165 to 262 mg of NH3∙d−1 over a 14-day period. Taking the parameters that led to the best results in experiments 1 and 2, different types of ammonia capture solutions (H2SO4, water and carbonated water) were finally compared under refrigeration conditions (at 2 °C). A high NH3 recovery (81% in 7 days), comparable to that obtained with the H2SO4 solution (88%), was attained when chilled water was used as the capture solution. The presented results point to the need to carefully optimize the emitter concentration, flow rate, and type of capture solution to maximize the effectiveness of suspended GPM systems, and suggest that chilled water may be used as an alternative to conventional acidic solutions, with associated savings.

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Nitrate vulnerable zones (NVZs) are areas considered to be at high risk of water pollution due to an excess of nitrates and, according to European regulations, codes of good agricultural practice are to be implemented by farmers, such as reducing doses of the applied fertilizers, or the use of fertilizers that minimize nitrate leaching. In this work, the influence of organic fertilization with dried pig manure (DPM) as compared to mineral fertilization with ammonium sulfate nitrate with 3,4-dimethylpyrazole phosphate nitrification inhibitor was studied in a barley crop planted in a NVZ in Fompedraza (Valladolid, Spain). Organic and mineral fertilizers were applied at different rates (85, 133 and 170 kg N·ha −1 ·year −1 vs. 90 and 108 kg N·ha −1 ·year −1 , respectively) over a three-year period, in a randomized complete block design with six treatments and four blocks. DPM-based fertilization resulted in a 65% increase in crop yield as compared to the control soil, reaching 1800 kg·ha −1 for an application rate of 85 kg N·ha −1 ·year −1 . Higher DPM rates were found to increase the electrical conductivity and assimilable phosphorus, potassium, magnesium and organic matter contents, but did not lead to yield enhancements. Final nitrate and ammonium concentrations were lower than 10 mg·kg −1 and 20 mg·kg −1 , respectively, and no increase in soil salinity or heavy metal pollution was observed. DPM fertilization should be supplemented with small doses of inorganic fertilizers to obtain crop yields similar to those attained with mineral fertilization.

Gas-permeable membrane (GPM) technology is a possible solution to reduce ammonia (NH3) emissions from livestock housing. This paper presents the results obtained with an NH3-capture prototype based on the use of expanded polytetrafluoroethylene (ePTFE) membranes in real conditions in a gestating sow house and a free-range laying hen house, comparing them with the results obtained in controlled laboratory conditions for the same type of waste. The NH3 present in the air of the livestock housing was captured by reaction with an acidic solution flowing inside the membranes. The periods of continuous operation of the pilot plant were 232 days at the pig farm and 256 days at the poultry farm. The NH3 recovery rate at the end of those periods was 2.3 and 0.4 g TAN·m−2·d−1 in the pig and the poultry farms, respectively. The limiting factor for the capture process was the NH3 concentration in the air, with the highest recovery occurring in the most concentrated atmosphere. Differences in NH3 capture were observed between seasons and farms, with capture efficiencies of 1.62 and 0.33 g·m−2·d−1 in summer and 3.85 and 1.20 g·m−2·d−1 in winter for pig and poultry farms, respectively. The observed differences were mainly due to the higher ventilation frequency in the summer months, which resulted in a lower NH3 concentration inside the houses compared to the winter months. This is especially important when considering the real applicability of this technology. The results obtained suggest that GPM technology holds promise for limiting NH3 emissions from livestock housing with NH3 ambient concentrations close to 20 ppm or as part of manure storage facilities, given that it allows for recovery of nitrogen in a stable and concentrated solution, which can be used as a fertilizer.

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