This study investigates the effect of mechanically activated recycled concrete powder (RCP) on Portland cement mixtures with an RCP content of 20 % is investigated. The setting time tests showed that the inclusion of RCP increased the setting time in almost all cases. However, better results were achieved with the mechanically activated RCP than with the RCP raw material additive. In addition, the final setting time was reduced by almost one hour overall (from 380 min to 325 min) when the 3 minute grind was used, which had a similar setting time to Portland cement. The mixtures showed similar behavior in the rheological tests, with the initial shear stress decreasing slightly after the addition of the RCP. Overall, the compressive strength of the RCP-containing mixtures decreased compared to the cement-containing samples. However, a positive effect of milling was observed, as the lowest compressive strength reduction of 29.34 % was achieved by the RCP ground for 3 minutes.
This research article on the disposal of microplastics in wastewater treatment plants provides a comprehensive overview of current research and technologies for the management of microplastic pollution in water. The study highlights the effectiveness of tertiary chemical treatments, especially disk filter membranes with large-pore fiber membranes (10-20 μm) to improve the removal of microplastics, with a rejection rate of about 41 % means Coagulation, membrane separation. Various other processes such as adsorption, magnetic separation and biodegradation are investigated and challenges such as membrane fouling and secondary pollution. It emphasizes the importance of interdisciplinary collaboration between stakeholders, researchers and the public in system design and industry to effectively address microplastic pollution. The study highlights the need for further studies to evaluate the performance of microplastic removal technologies under different conditions and to fill existing knowledge gaps in order to develop effective pollution control strategies. The article emphasizes the crucial role of advanced medical technology and collaborative efforts.
The repurposing of treated effluent for agricultural use and to augment potable water supplies is increasingly recognized as a reliable water source. This study investigates the ecological consequences of untreated or insufficiently treated wastewater. The quality of wastewater adversely affects the condition of receiving water bodies. Wastewater is a primary contributor to many water contamination issues. The substandard quality of discharged wastewater leads to the deterioration of the receiving water body. Microorganisms present in wastewater serve numerous advantageous roles within the systems; yet, many are considered significant contributors to different waterborne diseases. Additionally, wastewater must be comprehensively treated before release to mitigate pathophysiological hazards to users and aquatic ecosystems. The release of untreated and insufficiently processed wastewater into water bodies has both immediate and enduring effects on the ecology and human health. The sole approach to mitigate the effects of wastewater on the environment, human health, and public welfare is to rigorously implement water and environmental rules that safeguard both rural and urban regions, while ensuring sufficient wastewater treatment before release. This can be achieved by employing appropriate treatment methods that mitigate risks to public health and the environment. Attaining pristine wastewater discharge into receiving waters necessitates meticulous planning, sufficient and appropriate treatment, regular monitoring, and adherence to regulations.
In order to ensure self-sufficiency and a stable supply of essential mineral raw materials within the EU, the European Raw Materials Alliance (ERMA) was established. One of its key objectives is to secure access to sustainable raw materials and support the exploration and mining of these materials within the EU. Metallic magnesium has been included on the list of critical minerals for EU countries since 2011. The most suitable raw materials for Mg production by the silicothermic reduction method are dolomite or magnesite, and the Slovak Republic has considerable resources of these carbonate raw materials. For technological research, six samples of dolomite from different deposits were selected. The samples were annealed at selected temperatures and characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), and chemical analyses. Results published in the conference paper by Danková et al. (2025) showed that for the silicothermic reduction of magnesium, it is necessary to verify the calcination conditions for each sample individually and determine the influence of hydration activity or active sites in their structure to increase magnesium reduction. The selected calcined dolomite samples were subjected to repeated DTA/TG analysis after a two-month interval to determine their hydration. Based on these results, the dolomite sample designated as ST-1, calcined under specified conditions, was used for the laboratory experiment of silicothermic reduction of magnesium. The resulting product was analyzed by SEM/EDX, which detected a high ratio of metallic magnesium (in at. %).
Recycling provides environmental benefits, including energy savings, reduced waste volumes, and reduced emissions associated with energy use. Cell (mobile) phones are widely used throughout much of the world. However, less than one percent of the millions of cell phones retired and discarded annually are recycled. Almost all materials used in cell phone manufacturing - metals, plastics, batteries, and packaging - can be recovered and recycled into new products. This study summarizes recycling technologies for waste cell phones and, as a case study, examines the potential for recovering valuable metals from waste cell phones using acidic leaching. The process steps include dismantling waste mobile phones, preprocessing to separate materials, and directing them to final treatment processes. In the leaching experiments, sulfuric, nitric, and hydrochloric acids were used. In the sulfuric acid leaching experiment, the effects of acid concentration, temperature, peroxide addition, and leaching time on metal dissolution efficiencies were investigated. Leaching efficiencies achieved were 97.9 % Fe in 8 mol H2SO4, 88 % Pb, 100 % Ni, 90.4 % Co, and 4.1 % Cu in 1 mol HNO3 solutions, 100 % Pb, and 100 % Al in 4 mol HCl, all within one hour. Therefore, for effective leaching of all metals, a sequential leaching process using different acids is recommended.
