Mineral and essential element measurements in dolphin bones using two analytical approaches

We explored the potential of using energy-dispersive X-ray analysis (EDX), a non-destructive technique, to assess elemental contents in dolphin bones. Specimens were deposited in museum collections, and prepared by different methodologies. Fifty eight Commerson’s dolphins (Cephalorhynchus c. commersonii) chevron bones and 24 Franciscana dolphins (Pontoporia blainvillei) were analysed. The EDX allowed us to detect the following elements: Ca, P, Na, Mg, Fe, K, Zn, S, Cl and Al; and quantify their proportion (weight percent of element). Principal components analysis differentiates two groups according to the cleaning procedures applied, supporting that cleaning methods could influence the chemical integrity of bone. No significant age-dependent increase was found for elements analysed in species, and no significant differences were found between sex and physical maturity stages. Alternative assessment was made through atomic absorption spectrophotometry, providing quantitative information on the principal elements in bones (Ca, P, Mg, Na, Fe and Zn) and allowing comparisons with other studies. A standard protocol for bone cleaning and conditioning is needed to exclude any effect on the mineral integrity of calcified tissue. This would enable future comparative studies on the bone mineral matrix over time housed in natural history museums or other scientific collections.     

Use of fluff in a coking coal blend in a pilot scale

Journal of Material Cycles and Waste Management - Fluff is a shredder waste made up mostly of polymeric material generated in semi-integrated steel manufacturing plants, which is usually disposed...     

Macro-fungal (Agaricus bisporus) wastes as an adsorbent in the removal of the acid red 97 and crystal violet dyes from ideal colored effluents

The wastes from the macro-fungus Agaricus bisporus were used as an eco-friendly and low-cost adsorbent for the treatment of colored effluents containing the recalcitrant dyes, acid red 97 (AR97) and crystal violet (CV). The macro-fungal waste presented an amorphous structure, composed of particles with different sizes and shapes. Also, it presents typical functional chemical groups of proteins and carbohydrates with a point of zero charge of 4.6. The optimum conditions for the dosage were found to be as follows: 0.5 g L⁻¹ with an initial pH at 2.0 for the AR97 and 8.0 for the CV. From the kinetic test, it was found that it took 210 min and an adsorption capacity of 165 mg g⁻¹ for the AR97. Concerning the CV kinetics, it took 120 min to reach the equilibrium and it achieved an adsorption capacity of 165.9 mg g⁻¹. The Elovich model was the most proper model for describing the experimental data, achieving an R² ≥ 0.997 and MSE ≤ 36.98 (mg g⁻¹)². The isotherm curves were best represented by the Langmuir model, predicting maximum adsorption capacity of 372.69 and 228.74 mg g⁻¹ for the AR97 and CV, respectively. The process was spontaneous and favorable for both dyes. The ∆H⁰ values were 9.53 and 10.69 kJ mol⁻¹ for AR97 and CV, respectively, indicating physical and endothermic adsorption. Overall, the wastes from Agaricus bisporus have the potential to adsorb cationic and anionic dyes, thus solving environmental problems related to water quality and residue disposal.

     

Photodegradation of Diquat and Paraquat in aqueous solutions by titanium dioxide: evolution of degradation reactions and characterisation of intermediates

The titanium dioxide assisted photodegradation of Diquat and Paraquat herbicides solutions has been the subject of the present investigation, considering its direct application in the treatment of contaminated waters and soils. To have a better understanding of the photodegradation process, different types of TiO2, commercial and 'home prepared' Ti(1-x)FexO2 (x = 0% and 4%), were used as catalysts, using an UV light as radiation source. The degradation reactions were followed by UV spectroscopy and the intermediates and reaction products were characterised by electrospray ionisation mass spectrometry (ESIMS) combined with collision-induced dissociation (CID) and tandem mass spectrometry (MS/MS). The present study shows that, for photocatalytic degradation of Diquat and Paraquat solutions, a basic pH can be determinant, as well as the type of catalyst. The type of catalyst can also strongly influence the degradation pattern of the herbicide. Regarding complete degradation, we were able to show that Diquat is more persistent than Paraquat. During the photocatalytic processes, several intermediate and reaction products are sequentially formed, to which structures are proposed.