Effects of thermal treatment on the characteristics of pulp mill residue

In this study, the effects of thermal treatment at moderately low temperatures (Tmax: 525 °C) on the composition and properties of two distinct green liquor dregs (GLD) samples from two different pulp mills were investigated. This in-depth characterization was conducted with the aim of enabling the use of GLD as raw materials in cementitious applications (e.g., alkali-activated binders). The elemental composition of the GLD samples primarily comprised Ca, Mg, S, Na, and Mn. Analysis using x-ray diffractometry, an electron probe microanalyzer, and scanning electron microscopy revealed that calcite was the main crystalline phase, whereas layered double hydroxides with varying compositions constituted the primary amorphous phase. Characterization through Fourier-transform infrared spectroscopy and thermogravimetric analysis coupled with mass spectrometer analysis, indicated the loss of water and carbon during thermal treatment. Total organic carbon analysis showed that most of the removed carbon was organic, despite some remaining after thermal treatment at 525 °C. A leaching test was conducted to quantify the soluble Ca, Mg, Na, and K content, as well as pH variations. Overall, the findings suggest that thermal treatment enhances the potential of GLD samples for use in binder materials in the construction sector.

Suitable Cathode NMP Replacement for Efficient Sustainable Printed Li-Ion Batteries

N-methyl-2-pyrrolidone (NMP) is the most common solvent for manufacturing cathode electrodes in the battery industry; however, it is becoming restricted in several countries due to its negative environmental impact. Taking into account that ∼99% of the solvent used during electrode fabrication is recovered, dimethylformamide (DMF) is a considerable candidate to replace NMP. The lower boiling point and higher ignition temperature of DMF lead to a significant reduction in the energy consumption needed for drying the electrodes and improve the safety of the production process. Additionally, the lower surface tension and viscosity of DMF enable improved current collector wetting and higher concentrations of the solid material in the cathode slurry. To verify the suitability of DMF as a replacement for NMP, we utilized screen printing, a fabrication method that provides roll-to-roll compatibility while allowing controlled deposition and creation of sophisticated patterns. The battery systems utilized NMC (LiNi _x Mn _y Co _z O₂) chemistry in two configurations: NMC523 and NMC88. The first, well-established NCM523, was used as a reference, while NMC88 was used to demonstrate the potential of the proposed method with high-capacity materials. The cathodes were used to create coin and pouch cell batteries that were cycled 1000 times. The achieved results indicate that DMF can successfully replace NMP in the NMC cathode fabrication process without compromising battery performance. Specifically, both the NMP blade-coated and DMF screen-printed batteries retained 87 and 90% of their capacity after 1000 (1C/1C) cycles for NMC523 and NMC88, respectively. The modeling results of the drying process indicate that utilizing a low-boiling-point solvent (DMF) instead of NMP can reduce the drying energy consumption fourfold, resulting in a more environmentally friendly battery production process.

Antifungal and antibiofilm activities of the essential oil of leaves from Lippia gracilis Schauer against phytopathogenic fungi

AIMS

This study aimed to evaluate the antifungal and antibiofilm effects of essential oil (EO) from leaves of Lippia gracilis and its major constituents, thymol and carvacrol, against phytopathogenic fungi.

METHODS AND RESULTS

The leaves of L. gracilis were hydrodistilled to obtain the EO and the chemical composition was determined by GC/MS analysis. The antifungal activity of EO of L. gracilis was evaluated on the vegetative and mycelial growth of Colletotrichum gloeosporioides, Colletotrichum lindemuthianum, Fusarium oxysporum and Fusarium solani. In addition, the ability of the oil to inhibit fungal biofilm formation was assessed by total biomass quantification using crystal violet staining, analysis of metabolic activity, and scanning electron microscopy (SEM). Moreover the antifungal and antibiofilm activities of the monoterpenes, thymol and carvacrol, present in EO of L. gracilis were evaluated against F. oxysporum. The analysis of the chemical composition of EO extracted from L. gracilis, revealed the presence of monoterpenes (94·13%), which included carvacrol (48·57%) and thymol (7·78%), and 4 sesquiterpenes (3·74%). In general, EO showed significant antifungal activity and inhibited the formation of fungal biofilms. Furthermore, thymol and carvacrol showed significant antifungal and antibiofilm activities against F. oxysporum. SEM images showed structural changes in fungal morphology upon treatment with EO of L. gracilis.

CONCLUSION

The results presented in this study showed promising antifungal and antibiofilm effects of EO of L. gracilis and its major components, carvacrol and thymol.

SIGNIFICANCE AND IMPACT OF THE STUDY

These findings indicate that the EO extracted from L. gracilis, and the monoterpenes, carvacrol and thymol have a great potential as antifungal and antibiofilm agents. Furthermore, this is the first report of the antibiofilm activity of the EO of L. gracilis and its major components against phytopathogenic fungi.

Environmental matching used to predict range expansion of two invasive corals (Tubastraea spp.)

The scleractinian corals Tubastraea coccinea Lesson, 1829 and T. tagusensis Wells, 1982 have invaded reefs along Brazil's coastline. Over the period 2011-2017 a standard, fast, easily repeatable semi-quantitative method was used to produce maps of distribution and a site (n = 77) specific Relative Abundance Index (RAI) to determine range expansion at Cabo Frio, an upwelling region. Invaded sites doubled from six to 12 over the period (one per year) and mean abundance increased tenfold from 0.2 to 2.6 RAI and 0.22 to 1.8 RAI (T. coccinea and T. tagusensis respectively). Site specific oceanographic conditions (temperature, salinity and water transparency) and distance from currently invaded sites (a proxy for propagule pressure) were chosen and used as determinants of invasion success in order to model the expansion. Model results compared favourably with empirical measurements and the simple, regional, and spatially explicit model predicted future range expansion under 10 and 20 year scenarios.