Since the realization in the 1930s that elevated fluoride concentrations in drinking water can have detrimental effects on human health, new methods have been progressively developed in order to reduce fluoride to acceptable levels. In the developing world the necessity for filtration media that are both low-cost and sourced from locally available materials has resulted in the widespread use of bone char. Since the early 1990s metallic iron (Fe⁰) has received widespread use as both an adsorbent and a reducing agent for the removal of a wide range of contaminant species from water. The ion-selectivity of Fe⁰ is dictated by the positively charged surface of iron (hydr)oxides at circumneutral pH. This suggests that Fe⁰ could potentially be applied as suitable filter media for the negatively charged fluoride ion. This communication seeks to demonstrate from a theoretical basis and using empirical data from the literature the suitability of Fe⁰ filters for fluoride removal. The work concludes that Fe⁰-bearing materials, such as steel wool, hold good promise as low-cost, readily available and highly effective decentralized fluoride treatment materials.

Researchers on metallic iron (Fe⁰) for environmental remediation and water treatment are walking in a valley of confusion for 25 years. This valley is characterized by the propagation of different beliefs that have resulted from a partial analysis of the Fe⁰/H₂O system as (1) a reductive chemical reaction was considered an electrochemical one and (2) the mass balance of iron has not been really addressed. The partial analysis in turn has been undermining the scientific method while discouraging any real critical argumentation. This communication re-establishes the complex nature of the Fe⁰/H₂O system while recalling that, finally, proper system analysis and chemical thermodynamics are the most confident ways to solve any conflicting situation in Fe⁰ environmental remediation.

The high cost of advanced technology for defluoridation has, since the late 20th century, triggered the search for low-cost water defluoridation methods. One such effort involves the use of plant biomass materials. Over the past thirty years, our understanding of fluoride sorption mechanisms of non-activated plant biomass has not significantly advanced, partly due to inconsistencies and incompleteness of defluoridation studies. This research aimed at investigating how inconsistencies and incomplete selections of study parameters have impacted our understanding of key defluoridation properties of non-activated plant biomass materials, specifically fluoride sorption mechanisms. The study reviewed 37 studies that explored the application of non-activated plant biomass in water defluoridation, comparing methods and findings while identifying reasons for deficits. Findings revealed significant inconsistencies and incompleteness in the selection of study parameters, leading to unsubstantiated proposals for plausible sorption mechanisms. This has deprived the research community of a thorough understanding despite thirty years of studies in the field. This study, therefore, concludes that selection study parameters is a crucial component in enhancing our understanding of fluoride sorption properties of plant biomass materials. For an in-depth understanding of fluoride sorption mechanisms, this study identified three crucial parameters that must be included in future studies: the effect of pH variation, the point of zero charge of the adsorbent, and FT-IR spectral shifts.

Objective: The rise of bacterial resistance presents significant challenges to the pharmaceutical industry. Researchers have focused on finding ways to counteract microbial resistance, with one approach being the exploration of synergistic effects from combining drugs or natural products. This study investigates the antibacterial effect of combining ethanolic extracts of guava leaves and beetroot against Staphylococcus aureus , and potential chemical interactions between the bioactive compounds. Methods: Using disk diffusion antibiotic sensitivity testing, the study compares the antibacterial activity of individual plant extracts with the combined extract. Additionally, the UV/Vis spectra of the individual and combined extracts were compared to assess chemical interactions. Results: Findings indicate that the combination of guava leaves, and beetroot extracts has a weak synergistic effect against S. aureus , with a Fractional Inhibitory Concentration (FIC) index of 0.25. The UV/Vis spectrum showed decreased absorbance at 245–280 nm and increased absorption at 365–400, 475, and 675 nm, suggesting the conversion of compounds and chemical interactions between bioactive compounds in the combined extract. Conclusion: The study concludes that combining guava leaves and beetroot extracts results in a weak synergistic antibacterial effect against S. aureus , with bioactive compounds interacting to form derivatives that enhance activity. Further studies are, therefore, recommended to elucidate the mechanisms of these interactions and their effects against S. aureus.