As the current excessive accumulation of fluoride (F⁻) in the environment can be hazardous to human health, it is essential to remove fluoride from wastewater. In this study, diatomite (DA) was used as a raw material and modified using aluminum hydroxide (Al-DA) for use in the adsorption of F⁻ from water bodies. SEM, EDS, XRD, FTIR, and Zeta potential characterization analyses were carried out; adsorption tests and kinetic fitting were performed, and the effects of pH, dosing quantity, and presence of interfering ions on the adsorption of F⁻ by the materials were investigated. The results show that the Freundlich model effectively describes the adsorption process of F⁻ on DA, which therefore involves adsorption-complexation interactions; however, the Langmuir model effectively describes the adsorption process of F⁻ on Al-DA, corresponding to unimolecular layer adsorption mainly via ion-exchange interactions, that is, adsorption is dominated by chemisorption. Aluminum hydroxide was shown to be the main species involved in F⁻ adsorption. The efficiency of F⁻ removal by DA and Al-DA was over 91% and 97% for 2 h, and the adsorption kinetics were effectively fit by the quasi-secondary model, suggesting that chemical interactions between the absorbents and F⁻ control the adsorption process. The adsorption of F⁻ was highly dependent on the pH of the system, and the maximum adsorption performance was obtained at pH 6 and 4. The optimal dosage of DA and Al-DA was 4 g/L. Even in the presence of interfering ions, the removal of F⁻ on Al-DA reached 89%, showing good selectivity. XRD and FTIR studies showed that the mechanism of F⁻ adsorption on Al-DA involved ion exchange and the formation of F–Al bonds.

This study investigated the spatial distribution, sources, and health risks of heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in agricultural topsoils in Fuxin, China. One-hundred and thirty-eight topsoil samples were collected from Fuxin in August 2017. Except for Cu, Hg, and Pb, the mean concentrations of other heavy metals surpassed their respective background values. The mean concentration of Cd was nine times that of the background value. For the majority of heavy metals, contents in the Haizhou and Xihe areas and south of Fumeng County were significantly higher than those of other areas. The results of the geoaccumulation and potential ecological risk indexes revealed that Cd demonstrated moderate contamination. The Haizhou and Xihe areas were considerable risk areas, whereas heavy metals in other areas posed low risks. Results of the health risk assessment revealed that the non-carcinogenic risks caused by heavy metals were small-beer. The carcinogenic risks caused by Ni, Cr, and As surpassed acceptable levels. Based on the results of source apportionment, which is based on positive matrix factorization, agricultural sources contributed to half of the concentration of heavy metals; industrial and traffic sources contributed 32.12% and 14.97%, respectively.

Perfluorooctanoic acid is ubiquitous in water bodies and is detrimental to the health of organisms. Effectively removing perfluorooctanoic acid (PFOA), a persistent organic pollutant, has been a hot topic around the world. With traditional physical, chemical, and biological methods, it is difficult to effectively and completely remove PFOA, the costs are high, and it is easy to cause secondary pollution. There are difficulties in applying some technologies. Therefore, more efficient and green degradation technologies have been sought. Photochemical degradation has been shown to be a low-cost, efficient, and sustainable technique for PFOA removal from water. Photocatalytic degradation technology offers great potential and prospects for the efficient degradation of PFOA. Most studies on PFOA have been conducted under ideal laboratory conditions at concentrations that are higher than those detected in real wastewater. This paper summarizes the research status of the photo-oxidative degradation of PFOA, and it summarizes the mechanism and kinetics of PFOA degradation in different systems, as well as the influence of key factors on the photo-oxidative degradation and defluoridation process, such as system pH, photocatalyst concentration, etc. PFOA photodegradation technology’s existing problems and future work directions are also presented. This review provides a useful reference for future research on PFOA pollution control technology.

At the intersection of technological evolution and escalating computational demand, the role of optics is reemerging as a transformative force in the field of computing. This article examines the evolving landscape surrounding optical advantages in computing, focusing on current trends and prospects. Optical computing finds applications across various domains, such as parallel processing, high-speed signal processing, energy efficiency, quantum computing, machine learning, secure communication, and signal/image processing. This review synthesizes insights from scholarly articles, peer-reviewed journals, and academic papers to analyze the potential and challenges of leveraging optics for computational tasks. The literature review also critically examines the challenges of adopting optical computing solutions. The recommended multidimensional approach to overcoming adoption challenges involves holistically addressing integration challenges, manufacturing complexities, and infrastructure needs where collaboration will catapult optical computing into an era of computational power. Through a multidimensional exploration, this article provides a comprehensive understanding of the opportunities and challenges in harnessing optical advantages in computing, positioning optical computing as a revolutionary force with far-reaching consequences. Consequently, this review offers insight and guides researchers, industry professionals, and policymakers toward a computational future that maximizes the advantages of optical computing in specific and pivotal application areas, transcending existing boundaries.

Contamination and adverse effects from various pollutants often appear in abandoned industrial regions. Thus, nine groundwater samples were collected from the vicinity of the fluorochemical industry in Fuxin City, Liaoning Province, to determine concentrations of the ten heavy metals arsenic (As), chromium (Cr), cadmium (Cd), lead (Pb), nickel (Ni), copper (Cu), manganese (Mn), zinc (Zn), iron (Fe) and mercury(Hg), as well as those of fluorine (F⁻) and eighteen poly- and perfluorinated substances (PFASs), analyse correlation relationships, and assess the health risks for different age groups. The results showed that the levels of fluorine (F⁻) (0.92–4.42 mg·L⁻¹), Mn (0.0005–4.91 mg·L⁻¹) and Fe (1.45–5.61 mg·L⁻¹) exceeded the standard limits for drinking water. Short chain perfluorobutanoic acid (PFBA) (4.14–2501.42 ng·L⁻¹), perfluorobutane sulfonate (PFBS) (17.07–51,818.61 ng·L⁻¹) and perfluorohexanoic acid (PFHxA) (0.47–936.32 ng·L⁻¹) were the predominant substances from the PFASs group. No individual PFASs levels had significant relationships with F⁻ or heavy metal contents. There was a positive relationship between short chain PFASs concentrations and water depth and a negative relationship between long chain PFASs concentration and water depth. The hazard quotient (HQ) decreased in the order F⁻ > heavy metals > PFASs and also decreased for older age groups. In addition, As, Fe, Mn and perfluorooctanoic acid (PFOA) were the main sources of risk from the heavy metal and PFASs groups, respectively.

Water containing high concentrations of fluoride is widely distributed and seriously harmful, largely because long-term exposure to fluoride exceeding the recommended level will lead to fluorosis of teeth and bones. Therefore, it is imperative to develop cost-effective and environmentally friendly adsorbents to remove fluoride from polluted water sources. In this study, diatomite (DA), calcium bentonite (CB), bamboo charcoal (BC), and rice husk biochar (RHB) were tested as adsorbents to adsorb fluoride (F^‐) from water, and this process was characterized by scanning electron microscopy (FEI-SEM), X-ray diffraction (XRD), and Fourier-transform infrared spectroscopy (FT-IR). The effects of pH, dosage, and the initial mass concentration of each treatment solution upon adsorption of F^‐ were determined. Kinetic and thermodynamic models were applied to reveal the mechanism of defluoridation, and an orthogonal experiment was designed to obtain the optimal combination of conditions. The results show that the surfaces of CB, BC, and RHB have an irregular pore structure and rough surface, whereas DA has a rich pore structure, clear pores, large specific surface area, and high silica content. With regard to the adsorption process for F^‐, DA has an adsorption complex electron interaction; that of CB, BC, and RHB occur mainly via ion exchange with positive and negative charges; and CB on F^‐ relies on chemical electron bonding adsorption. The maximum adsorption capacity of DA can reach 32.20 mg/g. When the mass concentration of fluoride is 100 mg/L, the pH value is 6.0 and the dosage is 4.0 g/L; the adsorption rate of F^‐ by DA can reach 91.8%. Therefore, we conclude that DA soil could be used as an efficient, inexpensive, and environmentally friendly adsorbent for fluoride removal, perhaps providing an empirical basis for improving the treatment of fluorine-containing water in the future.