Applying carbon materials derived from cellulose for the removal of malathion and chlorpyrifos in food processing

The growing use of pesticides to enhance food production leads to their presence in food samples, necessitating the creation of efficient methods for their elimination. This study demonstrates that activated carbon materials derived from cellulose can effectively remove malathion and chlorpyrifos from liquid samples, even when found in complex matrices. Adsorbents were carbonized at 850 °C and activated in the temperature range between 670 and 870 °C where activation time was from 30 to 180 min and CO2 flow rate from 10 to 80 L h −1). After that, materials were characterized in terms of physical and chemical properties using SEM, EDX, BET, FTIR, Raman, and Zeta potential. The synthesized materials were tested by removing malathion and chlorpyrifos from lemon juice and mint ethanol extracts. The results showed that these materials remove these pesticides to a high degree. Furthermore, some of the developed adsorbents exhibit the ability to selectively remove chlorpyrifos in the presence of malathion. These selected materials remain unaffected by the intricate compositions of real samples. Additionally, the adsorbent can be regenerated at least five times without significant performance degradation. Our findings propose that the adsorptive elimination of contaminants from food can substantially enhance food safety and qualityTwenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

The impact of thermal treatment on spent coffee grounds for chlorpyrifos removal from water

Coffee is one of the world's most beloved beverages, with an annual production exceeding 10.5 million tons. However, the extensive generation of spent coffee grounds (SCGs) raises environmental concerns when carelessly disposed of. Also, the growing issue of pesticide contamination in water and food poses an environmental challenge. Given the hazardous nature of pesticides and their potential to inflict severe health consequences, it is important to understand how these compounds interact with biowaste materials. In this study, the spent coffee grounds are thermally treated at 400, 650, and 900 °C and named C400, C650, and C900, respectively. The synthesized materials and the initial SCG have been characterized using SEM, EDX, and FTIR. The kinetics of chlorpyrifos (CHP) adsorption on these materials has been investigated using pseudo-first-order (PFO), pseudo-second-order (PSO), Elovich, and intraparticle diffusion kinetic models. Adsorption experiments were done at three temperatures (25, 30, and 35°C), and the obtained experimental results were analyzed using non-linear Freundlich, Langmuir, Temkin, and Dubinin-Radushkevich isotherm models. Thermodynamics of the process has also been investigated. The results showed that the CHP adsorption process on all four materials fits equally well in both PFO and PSO and that the equilibrium time is 400 min. Isotherm study of adsorption on all three temperatures shows very good fitting in both Freundlich and Langmuir isotherm models. Langmuir isotherm model revealed that the maximum concentration of CHP that can be adsorbed by 1g of materials (qmax) is 2.31 mg g-1 , 19.43 mg g-1 , 4.67 mg g-1 , and 10.98 mg g-1 for SCG, C400, C650, and C900 respectfully. Thermodynamic parameters revealed that the adsorption of CHP on all investigated materials is a spontaneous process. By increasing the adsorption temperature, the qmax value increases for SCG, C650, and C900, indicating that the process is exothermic, and decreases in the case of C400, indicating that the process is endothermic.Twenty-First Young Researchers’ Conference - Materials Science and Engineering: Program and the Book of Abstracts; November 29 – December 1, 2023, Belgrade, Serbi

Chemisorption as the essential step in electrochemical energy conversion

Growing world population and energy demands have placed energy conversion and storage into the very centre of modern research. Electrochemical energy conversion systems including batteries, fuel cells, and supercapacitors, are widely considered as the next generation power sources. Even though they rely on different mechanisms of energy conversion and storage, fundamentally these are all electrochemical cells, operating through processes taking place at the solid/liquid interfaces, i.e. electrodes. Considering the interfacial nature of electrodes, it is clear that adsorption phenomena cannot be neglected when considering electrochemical systems. More than that, they are of crucial importance for electrochemical processes and represent an essential step in electrochemical energy conversion. In this contribution we give an overview of the phenomena underlying the operation of sustainable metal-ion batteries, fuel cells and supercapacitors, ranging from electrocatalytic reactions and pseudo-faradaic processes to purely adsorptive processes, emphasizing the types, roles and significance of chemisorption. We review experimental and theoretical methods which can provide information about chemisorption in the mentioned systems, stressing the importance of combining both approaches

DFT Study of Hydrogen Interaction With Nickel and Nickel Alloys

Interaction of nickel and nickel alloys with hydrogen is a topic of interest in hydrogen production and storage, and also due to the unwanted hydrogen embattlement in the nickel-containing alloys. The strength of the metal-hydrogen bond plays a crucial role in electrocatalysis or hydrogen sorption; therefore, correlating electronic structure and stability of metal hydrides is of broad interest for material design. We present a theoretical investigation of the interaction of nickel with hydrogen, concentrating on the influence of volume and chemical surroundings on the electronic structure and magnetism in the studied systems. Density functional theory calculations are done using the all-electron FPLAPW method, as included in the Wien2k program. In addition to various concentrations of hydrogen in the nickel, the influence of Hf and Pt on the structure, bulk modulus, and stability are examined. By augmenting these calculations with data from the NOMAD archive, we also search for structure-property relations and trends in numerous nickel-metal-hydride systems.TICMET23 : the 5th international conference of materials and engineering technology, November 13-16, 2023, Trabzon, Turkiy

Boron-doped graphene -- DFT study of the role of dopant concentration and oxidation on sodium and aluminium storage applications

Graphene is thought to be a promising materials for many applications. However, pristine graphene is not suitable for most electrochemical devices, where defect engineering is crucial for its performance. We demonstrate how boron doping of graphene can alter its reactivity, electrical conductivity and potential application for sodium and aluminium storage, with the emphasis on novel metal-ion batteries. Using DFT calculations, we investigate both the influence of boron concentration and the oxidation of the material, on the mentioned properties. It is demonstrated that the presence of boron in graphene increases its reactivity towards atomic hydrogen and oxygen-containing species, in other words, it makes B-doped graphene more prone to oxidation. Additionally, the presence of these surface functional groups significantly alters the type and strength of the interaction of Na and Al with the given materials. Boron-doping and oxidation of graphene is found to increase Na storage capacity of graphene by the factor of up to 4.Comment: 22 pages, 2 of which are supplementary information. 10 figures, 2 table