Comparison of dynamics and monotonic titrations as methods for determination of anionic surfactants in effluents

Tenzidi su organski spojevi koji na jednom kraju molekule imaju hidrofobnu ili lipofilnu grupu, a na drugom kraju molekule imaju hidrofilnu ili lipofobnu grupu. To su tvari koje snižavaju površinsku napetost, a pri određenim koncentracijama u otopini, kada se postigne kritična micelarna koncentracija (CMC) formiraju se u micele. Dijele se na kationske, neionske, anionske i amfolitske, a zbog njihove široke primjene u raznim područjima potrebno je vrlo brzo i točno odrediti njihovu koncentraciju u proizvodima i otpadnim vodama. Najčešće korištena metoda za određivanje njihove koncentracije je potenciometrijska titracija. U eksperimentalnom dijelu rada određene su koncentracije anionskih tenzida u standardnoj otopini anionskog tenzida te u tri različita uzorka otpadnih voda, koristeći dvije metode potenciometrijske titracije: dinamičku i monotonu titraciju. Rezultati su uspoređeni kako bi se ispitalo postoji li razlika u mjerenjima pri određivanju točke ekvivalencije te koja metoda je preciznija i zašto.Surfactants are organic compounds that have a hydrophobic or lipophobic group on one end of the molecule and a hydrophilic or lipophilic group at the other. They are substances that reduce surface tension and at certain concentration in the solution, when the critical micellar concentration (CMC) is achieved, they form micelles. They are divided into cationic, nonionic, anionic and ampholitic. Due to their wide application in different areas, it is necessary to determine their concentration in products and effluents fast and accurate. The most commonly used method for determining their concentration is potentiometric titration. In the experimental part, anionic surfactant concentrations were determined in the standard anionic surfactant solution and in three different wastewater samples using two potentiometric titration methods: dynamic and monotonic titration. The results were compared to see if there is a difference between the measurements in equivalence point determination and which method is more precise and why

Comparison of dynamics and monotonic titrations as methods for determination of anionic surfactants in effluents

Tenzidi su organski spojevi koji na jednom kraju molekule imaju hidrofobnu ili lipofilnu grupu, a na drugom kraju molekule imaju hidrofilnu ili lipofobnu grupu. To su tvari koje snižavaju površinsku napetost, a pri određenim koncentracijama u otopini, kada se postigne kritična micelarna koncentracija (CMC) formiraju se u micele. Dijele se na kationske, neionske, anionske i amfolitske, a zbog njihove široke primjene u raznim područjima potrebno je vrlo brzo i točno odrediti njihovu koncentraciju u proizvodima i otpadnim vodama. Najčešće korištena metoda za određivanje njihove koncentracije je potenciometrijska titracija. U eksperimentalnom dijelu rada određene su koncentracije anionskih tenzida u standardnoj otopini anionskog tenzida te u tri različita uzorka otpadnih voda, koristeći dvije metode potenciometrijske titracije: dinamičku i monotonu titraciju. Rezultati su uspoređeni kako bi se ispitalo postoji li razlika u mjerenjima pri određivanju točke ekvivalencije te koja metoda je preciznija i zašto.Surfactants are organic compounds that have a hydrophobic or lipophobic group on one end of the molecule and a hydrophilic or lipophilic group at the other. They are substances that reduce surface tension and at certain concentration in the solution, when the critical micellar concentration (CMC) is achieved, they form micelles. They are divided into cationic, nonionic, anionic and ampholitic. Due to their wide application in different areas, it is necessary to determine their concentration in products and effluents fast and accurate. The most commonly used method for determining their concentration is potentiometric titration. In the experimental part, anionic surfactant concentrations were determined in the standard anionic surfactant solution and in three different wastewater samples using two potentiometric titration methods: dynamic and monotonic titration. The results were compared to see if there is a difference between the measurements in equivalence point determination and which method is more precise and why

Preparation and Analysis of Neutral Complexes of Cooper(ll) with Chromone-2,3-Carboxylic Acides

Kompleksni spojevi su spojevi koji sadrže centralni atom metala okruženog određenim brojem iona ili skupina, koje se nazivaju ligandi. Cilj ovoga rada bio je sintetizirati spoj s potencijalnim antikancerogenim svojstvima i/ili drugim terapeutskim svojstvima. Kao ligandi korišteni su derivati benzopirona, a kao izvor centralnog metala bakra(II) poslužile su soli tog metala (acetat, sulfat, nitrat i klorid). Kompleksi su pripravljeni te identificirani elementnom analizom kako bi im se odredila empirijska formula. Nakon provedenih analiza utvrđeno je da vjerojatna kemijska formula odgovara formuli $\left [ CuL_{2}\cdot 2H_{2}O \right ]$ .Complexes are compounds which consists of the central metal atom surrounded by a number of ions or groups, called ligands. The aim of this work was synthesis of the compounds with potential anticancer and/or other therapeutic properties. Benzopyrone derivatives were used as ligands, and copper(II) salts (acetate, sulfate, nitrate, and chloride) as the source of the metal copper(II). The complexes were prepared and identified by elemental analysis in order to determine the empirical formula. After analysis it was revealed that chemical formula of the newly synthesized compound is $\left [ CuL_{2}\cdot 2H_{2}O \right ]$

Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions

Preparation and Analysis of Neutral Complexes of Cooper(ll) with Chromone-2,3-Carboxylic Acides

Kompleksni spojevi su spojevi koji sadrže centralni atom metala okruženog određenim brojem iona ili skupina, koje se nazivaju ligandi. Cilj ovoga rada bio je sintetizirati spoj s potencijalnim antikancerogenim svojstvima i/ili drugim terapeutskim svojstvima. Kao ligandi korišteni su derivati benzopirona, a kao izvor centralnog metala bakra(II) poslužile su soli tog metala (acetat, sulfat, nitrat i klorid). Kompleksi su pripravljeni te identificirani elementnom analizom kako bi im se odredila empirijska formula. Nakon provedenih analiza utvrđeno je da vjerojatna kemijska formula odgovara formuli $\left [ CuL_{2}\cdot 2H_{2}O \right ]$ .Complexes are compounds which consists of the central metal atom surrounded by a number of ions or groups, called ligands. The aim of this work was synthesis of the compounds with potential anticancer and/or other therapeutic properties. Benzopyrone derivatives were used as ligands, and copper(II) salts (acetate, sulfate, nitrate, and chloride) as the source of the metal copper(II). The complexes were prepared and identified by elemental analysis in order to determine the empirical formula. After analysis it was revealed that chemical formula of the newly synthesized compound is $\left [ CuL_{2}\cdot 2H_{2}O \right ]$

Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions

Resolving a structural issue in cerium-nickel-based oxide

CeNiO3 has been reported in the literature in the last few years as a novel LnNiO3 compound with promising applications in different catalytic fields, but its structure has not been correctly reported so far. In this research, CeNiO3 (RB1), CeO2 and NiO have been synthesized in a nanocrystalline form using a modified citrate aqueous sol-gel route. A direct comparison between the equimolar physical mixture (n(CeO2) : n(NiO) = 1:1) and a compound RB1 was made. Their structural differences were investigated by laboratory powder X-ray diffraction (PXRD), selected area electron diffraction (SAED), transmission electron microscopy (TEM) with energy-dispersive X-ray spectroscopy detector (EDS), and Raman spectroscopy. The surface of the compounds was analyzed by X-ray photoelectron spectroscopy (XPS), while the thermal behaviour was explored by thermogravimetric analysis (TGA). Their magnetic properties were also investigated with the aim of exploring the differences between these two compounds. There were clear differences between the physical mixture of CeO2 + NiO and RB1 presented by all of these employed methods. Synchrotron methods, such as atomic pair distribution function analysis (PDF), X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) were used to explore the structure of RB1 in more detail. Three different models for the structural solution of RB1 were proposed. One structural solution proposes that RB1 is a single-phase pyrochlore compound (Ce2Ni2O7) while the other two solutions suggest that RB1 is a two-phase system of either CeO2 + NiO or Ce1–xNixO2 and NiO

B = W, Te) with ferromagnetic and dielectric properties for triboelectric energy harvesting

Four iron-based triple tungstate and tellurate perovskites have been synthesized in the nanocrystalline form using a simple sol–gel citrate route: Sr3Fe2WO9 (SFWO), Ba3Fe2WO9 (BFWO), Sr3Fe2TeO9 (SFTO), and Ba3Fe2TeO9 (BFTO). Strontium-based compounds crystallize in the tetragonal space group I4/m, while barium-based compounds crystallize in the hexagonal space group P63/mmc. All compounds possess a ferromagnetic order with high values for room-temperature magnetization. The magnetic state as traced by Mo¨ssbauer spectroscopy is heterogeneously related to disorder. The compounds also possess relatively high dielectric constants (20–199.16) measured at 1 MHz and a moderate loss factor. The synthesized triple perovskite compounds were utilized in the fabrication of vertical contact mode triboelectric nanogenerators (TENGs). The working mechanism and the electrical response of the TENGs were extensively studied. The TENG device based on BFTO/Kapton triboelectric layers produces the highest output of 88 V/2.69 mA. For the first time, the surface polarity of the triple perovskite was shown using a Kelvin probe force microscopy technique (KPFM), which elucidates the positive polarity of the triboelectric layer. Furthermore, the TENG device was used to charge several capacitors and to carry out the powering of electronics that make it an excellent choice for various self-powered applications

Sol-Gel Synthesis of Ceria-Zirconia-Based High-Entropy Oxides as High-Promotion Catalysts for the Synthesis of 1,2-Diketones from Aldehyde

Efficient Lewis-acid-catalyzed direct conversion of aldehydes to 1,2-diketones in the liquid phase was enabled by using newly designed and developed ceria–zirconia-based high-entropy oxides (HEOs) as the actual catalysts. The synergistic effect of various cations incorporated in the same oxide structure (framework) was partially responsible for the efficiency of multicationic materials compared to the corresponding single-cation oxide forms. Furthermore, a clear, linear relationship between the Lewis acidity and the catalytic activity of the HEOs was observed. Due to the developed strategy, exclusively diketone-selective, recyclable, versatile heterogeneous catalytic transformation of aldehydes can be realized under mild reaction conditions