Molecules

Valorizing coconut shell waste as a renewable lignocellulosic precursor offers a sustainable route to produce high-performance activated carbons for wastewater treatment. In this study, coconut shells were transformed into activated carbons through physical activation (air, CO₂, steam) and chemical activation (H₃PO₄, ZnCl₂, KOH), allowing direct comparison of how each method influences porosity and surface chemistry. Among the physically activated samples, steam activation produced the best material, A-ST, with S_BET = 738 m² g⁻¹, V_mi = 0.38 cm³ g⁻¹ and V_me = 0.07 cm³ g⁻¹. KOH activation yielded the top-performing carbon, A-KOH, achieving S_BET = 1600 m² g⁻¹, V_mi = 0.74 cm³ g⁻¹, and V_me = 0.22 cm³ g⁻¹. Adsorption tests with methylene blue, methyl orange, and orange G showed a clear link between physicochemical features and dye uptake. A-ST and A-KOH exhibited the highest capacities due to their wide micro–mesoporosity and favorable surface charge at the adsorption pH. In both cases, methylene blue was most strongly retained, confirming that large aromatic cations benefit from π–π interactions with graphene-like layers and easy micropore access. Overall, the results demonstrate that coconut-shell valorization is maximized when activation enhances both porosity and surface chemistry, enabling the production of tailored sorbents for the efficient removal of organic contaminants.

Deep Eutectic Solvents (DESs), particularly Naturally Available Deep Eutectic Solvents (NADESs), are increasingly regarded as green solvents due to their low vapor pressure, non-flammability, thermal stability, strong solvent power, and low toxicity. In line with Green Chemistry principles, the use of renewable and biocompatible components such as amino acids, lipids, and naturally derived acids enables the development of more sustainable solvent systems. This study addresses the need for environmentally safer NADESs by evaluating their physico-chemical suitability and environmental impact. Fifteen NADESs were prepared using naturally derived components and assessed for environmental safety. Biodegradability was evaluated using the OECD 301D Closed Bottle Test (CBT), while toxicity toward Raphidocelis subcapitata was examined to characterize ecotoxicological behavior. The results demonstrated that the synthesized NADESs exhibit high biodegradability levels and low toxicity toward microalgae. Toxicity control indicated no significant inhibition of microbial activity during biodegradation, suggesting favorable environmental compatibility. Overall, the findings indicate that the NADESs represent more sustainable solvent alternatives with low toxicological profiles. However, the potential role of these compounds in enhancing eutrophication processes cannot be excluded and warrants further investigation.

Berries are a valuable source of health-promoting substances, including vitamins, microelements, and polyphenols. Optimising the extraction efficiency of these compounds during processing is crucial to minimise their loss into the waste stream. Ultrasound technology is recognised as a sustainable and promising tool for improving extraction; however, previous literature has not sufficiently addressed the optimal point of its application in fruit puree processing, and its impact on the sensory properties of the final product has only occasionally been explored. As one of the first reports, this study aimed to determine the optimal moment for ultrasound application within a puree production scheme. In the second stage of the experiment, four recipes based on strawberry and haskap berry were tested. The results demonstrated the potential for enhancing sensory quality of puree by using an ultrasound treatment. It was found that the ultrasound-treated purees showed significantly higher pectin levels and improved rheological properties, while the content of anthocyanins and L-ascorbic acid remained mainly unchanged. This indicates that the non-thermal nature of ultrasound treatment can induce positive changes from a sensory and rheological point of view without causing the degradation of health-promoting compounds, offering a viable strategy for improving berry puree quality.