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The present work investigates the thermochemical valorization of camelina straw, which is a waste generated during the harvesting of Camelina sativa, an oilseed crop for the production of biodiesel or hydrotreated vegetable oil (HVO). In particular, it is focused on obtaining bio-oil via thermal or catalytic fast pyrolysis, which would be the first stage on a sequence of chemical processes for biofuel production. The catalytic interference of the inorganic matter present in the biomass was studied by preparing a batch of de-ashed camelina straw by washing with diluted nitric acid. Chemical analysis revealed this treatment effectively removed alkaline (K and Na) and alkaline earth (Ca and Mg) metals. Pyrolysis of de-ashed camelina straw led to higher mass and energy yields of bio-oil in water-free basis (bio-oil*), but with higher oxygen concentration. Catalytic pyrolysis over HZSM-5 was also studied in both raw and de-ashed feedstocks. This catalyst promoted mainly decarbonylation and decarboxylation reactions of the pyrolysis vapors, leading to much higher gas yields and lower of bio-oil*, but with better quality. Catalytic pyrolysis of untreated camelina straw exhibited a synergetic effect between both the inorganic matter and the external HZSM-5 catalyst, so that bio-oil* yield was the lowest (20 wt%) due to an extensive deoxygenation (18 wt% oxygen content), which resulted in the highest HHV obtained (37.3 MJ/kgdb). Significant differences were also found on the molecular composition of the bio-oils* with larger proportion of anhydro sugars when the biomass was de-ashed, while HZSM-5 strongly promoted the formation of oxygenated aromatics and aromatic hydrocarbons.

Dilute Pb(II) aqueous solutions were nanofiltered through a tubular membrane with good rejections. Retention was modeled using the Modified Spiegler–Kedem theory. The true retention, evaluated from concentration-polarization measurements, was similar to the observed value. The three characteristic parameters of the model: reflection coefficient $$\sigma$$ , solute permeability $$P$$ , and mass transfer coefficient $$K_{\text{m}}$$ were evaluated simultaneously. The reflection coefficient decreased with an increase in concentration until a plateau was reached at a concentration of 30 ppm. At low concentrations, the solute permeability increased with an increase in concentration, reaching a maximum at a concentration of 30 ppm. Subsequently, the permeability decreased with further increase in concentration, until at concentrations ≥ 100 ppm, it reached values close to those observed for very dilute solutions (< 10 ppm). Industrial scale nanofiltration of dilute solutions of Pb(II) is viable with high retentions. High pressures and tangential speeds and low temperatures increase retention. Moreover, moderately high concentrations of aqueous Pb(II) solutions can be reduced to totally sure levels in less than four nanofiltration steps. This makes nanofiltration a suitable tool to decrease Pb(II) levels below those recommended by the world health organization.