This study investigates the potential of using the mixture of titaniferous sand and attapulgite as adsorbents in a fixed bed adsorption process to remove a synthetic dye such as methylene blue in aqueous media. The different adsorbents were characterised by X-ray fluorescence spectroscopy and infrared spectroscopy. The different physico-chemical parameters such as pH, zero charge potential, bulk and absolute density, porosity and specific surface area were determined. The sizing algorithm used resulted in a number of transfer units (NUT) equal to 20.109, a height of transfer unit (HUT) equal to 0.515, a material transfer coefficient (Kya) equal to 3.159 and a height of the column (Z) equal to 1.05m. The influence of different experimental parameters such as initial dye concentration, adsorbent bed height and feed rate on the breakthrough curve was investigated. Various simple mathematical models such as Adams-Bohart and Thomas were applied in order to study the dynamic behaviour of the column and to estimate some kinetic coefficients through the experimental data obtained from the dynamic studies performed on the fixed bed. The results showed that the Thomas and Adams-Bohart models perfectly describe the behaviour of the breakthrough curves with values of coefficients of determination R2 that are higher than 0.90 except for the concentration of the dye equal to 50mg/L which has a coefficient R2 equal to 0.88.

The presence of toxic cyanobacteria in water bodies is a growing concern due to their potential adverse effects on public health and the environment. Microcystis aeruginosa and M. wesenbergii are known to be key microcystin producers in Bulgarian waterbodies. In this study, water samples were collected from various Bulgarian waterbodies during the summer months of 2021, and the presence and abundance of Microcystis species were analyzed using microscopy and PCR-based methods. The microcystin concentration in the water samples was measured using high-performance liquid chromatography (HPLC). The results showed that Microcystis aeruginosa and M. wesenbergii were the dominant species of cyanobacteria in the waterbodies sampled, with high microcystin concentration above the recommended safe limit for human consumption.

This study aimed to isolate and characterize fungal species from spoilt fruits in India and evaluate their implications for food safety and management. A total of 100 spoilt fruit samples were collected from local markets and analyzed using standard microbiological methods. The results revealed the presence of various fungal species, including Aspergillus, Penicillium, Fusarium, and Alternaria. The study highlights the need for effective food safety measures to prevent the growth and spread of fungal species in fruits. Spoilage of fruits is a common problem in the food industry, causing economic losses and health hazards. In this study, we aimed to isolate and characterize the fungal species responsible for spoilage of fruits in India and assess their potential risk to human health. Fungal species were isolated from spoilt fruits collected from different markets in India and identified using standard molecular and biochemical techniques. Our results revealed a high diversity of fungal species, including Aspergillus, Penicillium, Fusarium, and Alternaria, among others. These species are known to produce mycotoxins, which can cause serious health problems in humans, such as liver damage, cancer, and death. Thus, it is crucial to implement effective food safety and management strategies to prevent and control fungal spoilage of fruits and minimize the risk to human health. The findings of this study provide important insights for developing such strategies and promoting food safety in India.

Geogrid reinforcement is a commonly used technique to improve the stability of soil structures. In this study, we investigate the effect of geogrid reinforcement on the pullout parameters of sand through experimental methods. Pullout tests were conducted on sand samples with and without geogrid reinforcement using a custom-built pullout apparatus. The results showed that the geogrid reinforcement significantly increased the pullout force and displacement of the sand, and the pullout parameters, such as the interface friction angle, peak shear stress, and ultimate tensile strength, were also found to be higher for the geogrid-reinforced sand. The findings of this study can provide useful information for designing and constructing geogrid-reinforced soil structures.