Removal of Pharmaceutical Residues from Wastewater using Activated Carbon from Rice Husks

The presence of pharmaceutical residues in discharges that end up in rivers is a growing concern for the disruption of aquatic ecosystems and human health. The risk of exposure to these medical wastes becomes greater because they are not biodegradable even after sewage treatment. This study aimed to remove trimethoprim (antibiotic), paracetamol (painkiller), and nevirapine (anti-retroviral) from wastewater using activated carbon made from rice husks, an agricultural waste that was investigated as a potential adsorbent. The instrument used for analysis was a liquid chromatography-tandem mass spectrometer (LC-MS/MS). The powdered carbon of rice husks was carbonated at a temperature of 500oC and then activated by phosphoric acid to increase its porosity. After activation, it was successfully characterized by the use of Scanning electron microscopy which showed irregular cavities with open fine pores. Fourier transform infrared showed different functional groups which determined adsorbent- adsorbate interactions while X-ray diffraction revealed amorphous particle arrangement. The effects of the adsorbent dose, contact time, pH, and initial drug concentration were studied. Freundlich and Langmuir's isotherms were used in the evaluation of adsorption phenomena. Thus, obtained results showed that rice husks activated carbon is an effective adsorbent.

Application of different powdered forms of carbon for reinforcement of aluminum matrix composite materials by carbon and titanium carbide. А review

The paper considers the use of both traditional powdered carbon materials (graphite, soot, charcoal, shungite) and new carbon nanomaterials (nanodiamonds, fullerene, nanotubes, graphene) as a dispersed reinforcing phase in aluminum matrix composites (AMCs), and as reagents for the synthesis of titanium carbide (TiC) reinforcing particles in AMCs. It is observed that the key area of AMC development for significant improvement of their mechanical properties is the transition from micron-sized reinforcing particles to nanoparticles, and that the use of new carbon nanomaterials can play a decisive role in this. The technologies for producing such AMCs must provide the appropriate parameters of nanoparticles, their uniform distribution in the matrix and a strong adhesive interfacial bond with the matrix. However, it is highly difficult to meet these process requirements since carbon and titanium carbide nanoparticles are not wetted with aluminum at temperatures below 1000 °C and are prone to nanoparticle agglomeration due to interparticle adhesive forces that increase dramatically with the decreasing particle size. The paper provides an overview of advancements and unresolved issues in the use of powdered carbon forms in various solid-phase and liquid-phase methods of AMC production using various techniques to address these process challenges. It is shown that there is still a potential for using traditional carbon materials as well. Considerable attention is paid to the self-propagating high-temperature synthesis (SHS) of titanium carbide reinforcing particles with various carbon materials used to obtain aluminum matrix composites.

Investigation of the stability of polymer composites based on epoxy matrix and astralenes under exposure to high temperatures

Introduction. The paper considers one of the ways to improve performance characteristics of products based on polymer composites with epoxy matrix by improving their thermal stability and durability by introducing modifiers. Problem Statement. The objective of this study is to compare the heat resistance indicators of epoxy matrices of classical design with compositions improved by modification with carbon nanostructures. Theoretical Part. For basic information, the selection of modifying materials, the selection of the optimal composition of the binder based on epoxy resin, low-molecular hardener, plasticizer and filler was carried out. The technology of introducing modifiers into the structure of the epoxy matrix was developed. Thermogravimetric and differential thermal studies were used to analyze changes in the temperature of the beginning and the end of the thermal effect, the temperature of the maximum thermal effect, the amplitude value and width of the peak effect, the index of its shape, and the mass loss of heated samples depending on their formulation. Conclusion. The results of the study indicate the possibility of using epoxy resins filled with powdered carbon nanostructures in various areas of production due to the positive effect of additives on thermal stability indicators.

Influence of the ultrafine iron aluminide additive on the structure and properties of iron and copper powder materials

The results on the effect of introduction of iron aluminide of various chemical and phase compositions on the structure and mechanical properties of powdered carbon steel and tin bronze are presented. It is shown that the introduction of 0.5 % single-phase iron aluminide Fe3Al leads to an increase in the strength of powdered carbon steel by 30–40 MPa, of biphase Fe2Al5 –FeAl3 – by 80–90 MPa, 1 % – to an insignificant decrease in strength. When a single-phase iron aluminide in the powder steel structure is introduced, a decrease in cementite, differentiation is observed, aluminum diffusion into the substrate occurs, and when two-phase aluminide is introduced, the structure griding occurs as well. It is established that the introduction of 0.5 % single-phase iron aluminide into powder bronzes makes it possible to increase its strength by 80– 100 MPa, two-phase – leads to a reduction in strength by 40–50 MPa. Introduction of 1 % single-phase iron aluminide and 0.2–1 % biphasic aluminide causes a change in the morphology of the structure of the powder bronze due to alloying the copper with aluminum and iron.