Natural Clay Pyrophyllite Activation with Silver and Composite Characterization

In this work, a hybrid pyrophyllite/AgNPs system was designed by mechanochemical activation of pyrophyllite, Al2Si4O 10(OH) 2. Tuning this system’s properties is especially important in terms of possible biomedical applications. The reaction was triggered by adding 2, 5, and 10wt% of silver in the form of AgNO3, indicating green synthesis of AgNPs. Thereby, the grinding time was adjusted from 20 to 320 minutes. The collected samples were analyzed by FTIR, XRD, SEM with EDX, TGA, DTA and PSD. The FTIR spectra of the pyrophyllite/AgNPs system showed the disappearance of some bands characteristic of pyrophyllite itself due to breaking of some bonds during the grinding, and the appearance of some new bands. SEM-EDS analysis confirmed that pyrophyllite structure changed during the mechanochemical treatment, indicating a homogeneous distribution of silver along the analyzed surface. PSD analysis showed that the average particle size distribution is approximately the same for all samples, despite the different wt% of silver. While XRD patterns of samples with 2 and 5 wt% of AgNO 3 did not show reflections originating from silver, the peak at 38.16˚ of the pyrophyllite sample milled for 20 minutes with 10 wt% of silver could be assigned to silver in the metal form. DTA curves of pyrophyllite/AgNO 3 samples milled for 20, 80 or 320 min had similar shapes for different silver content added. TGA curves of pyrophyllite/AgNO 3 samples milled for 20 min with 2, 5, and 10 wt% of silver showed a total weight loss of about 10% while for samples milled for 320 min reduced weight loss was observed due to the agglomeration of particles.Published in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Application of a Pyrophyllite Modified Carbon Paste Electrode for the Detection of Carbendazim Fungicide in Water

This work aims to design an electrochemical sensor for pesticide detection in food and water based on modified pyrophyllite. Pyrophyllite is a phyllosilicate mineral of the chemical formula Al2Si4O 10(OH) 2. Modification of the carbon paste electrode was made by the addition of mechanochemically modified pyrophyllite. This type of modification is an environmentally friendly green chemistry method because it avoids using solvents. It was found that the best physicochemical characteristics for constructing the electrochemical sensor were shown by the sample that was milled for 15 minutes. Due to the delamination and bending of the layers, the size of the particles and crystallites decreases, and the electrocatalytic activity of the modified electrode is improved. Electrochemical measurements were performed by cyclic voltammetry in 0.5 mol/L H 2SO 4 and 1 mmol/L K 4Fe(CN) 6 in 0.1 mol/L KCl. The results showed that the electrode made of 50 % carbon paste and 50 % mechanochemically ground pyrophyllite for 15 minutes had the best properties. Quantitative detection of carbendazim was done by differential pulse stripping voltammetry at different pH in the Britton Robinson buffer. The developed method shows the linearity at pH 4 in the range of (1–10) mg/kg, with r = 0.999 and a detection limit of 0.3 mg/kg. In contrast to earlier works, in which carbendazim was determined electrochemically with different types of electrodes, the detection limits obtained with the carbon paste electrode modified with pyrophyllite, which was ground for 15 minutes in this work, are significantly lowerPublished in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Enhancing Pyrophyllite Adsorption Capabilities Via Sonic Treatment

Adsorption, a highly efficient water purification method and tool for pollution control, utilizes materials like clay. Compared to other commercial adsorbents, clay offers notable advantages including affordability, large specific surface area, accessibility, high ion exchange capacity, excellent adsorption properties, and non-toxicity. Pyrophyllite, among abundant natural clays, stands out due to its layered structure without interlayer cations or water molecules, offering favorable physical and chemical attributes. This study specifically examines the characterization of natural pyrophyllite ore treated with ultrasonic waves for 30 minutes and 6h. Analysis of samples using X-ray diffraction (XRD) technique indicates the removal of hard phases such as quartz and calcite from both treated samples in comparison to the raw ore. Energy dispersive X-ray spectroscopy (EDS) analysis, conducted as part of SEM-EDS analysis, revealed a significant reduction in the weight % of silicon. Specifically, the Si content decreased from 35.1 weight % in the raw ore to 28.7 after half an hour of treatment. Subsequently, after 6 hours, the most effective purification was achieved, with the Si content reaching only 18.6 weight %. Furthermore, UV-VIS analysis testing the sorption of a methylene blue solution in water reveals that ultrasonically treated pyrophyllite for 30 minutes achieves 97% efficiency after 24 hours, surpassing the 89% efficiency of the raw ore. Notably, after 6 hours of ultrasonic treatment, efficiency reaches nearly 98% after just 1 hour, confirming high efficacy of ultrasonic treatment on adsorption ability of pyrophyllite.Published in Bulletin of the Chemists and Technologistsof Bosnia and Herzegovina as Special Issue (2024)

Development of modified pyrophyllite carbon paste electrode for carbendazim detection

This study aims to design the pyrophyllite-adapted carbon paste electrode (pCPE) and test it for potential use in wastewater purification systems. Structural characterization of pure pyrophyllite ore and mechanically modified pyrophyllite in mortar and pestle has been followed by XRD, SEM, PSA, and FTIR. Electrochemical characteristics were studied by cyclic voltammetry of pyrophyllite CPE in sulfuric acid and potassium ferrocyanide, as redox model compounds. Delamination, gliding, and folding of the layers and a decrease in particle and crystallite size have been observed, leading to the excellent electrocatalytic activity of pCPE. The developed pCPE has numerous benefits such as a simple preparation method, rapid response, and good sensitivity. The oxidation peak of carbendazim appears in Britton-Robinson buffer solutions (pH 4) at +0.9 V vs. Ag/AgCl. The developed method is linear in the concentration range of 3.2–29.2 ng cm−3, with r = 0.999 and the limit of detection of 1.9 ng cm−3

Examination of the Sorption Properties of Ultrasonically Treated Pyrophyllite

Adsorption has proven to be the best water purification process and is considered a very effective method for pollution control in general. Clay is a natural material that occurs on the earth's surface and consists of hydrated aluminosilicates and other metal oxides such as Fe2O3, MgO and K2O. The use of clay as an adsorbent has considerable advantages over many other commercially available adsorbents. Low price, high specific surface area, availability, high ion exchange potential, excellent adsorption properties and non-toxicity are just some of its advantages. One of the most abundant natural clay materials is pyrophyllite. Pyrophyllite (Al2[Si4O10](OH)2) has a 2:1 layered structure whose layers are electroneutral, so pyrophyllite contains no cations or water molecules in its interlayers. As a result, it has good physical and chemical properties, making pyrophyllite one of the potential materials for the production of membranes for efficient water filtration. This study focuses on the characterization of natural pyrophyllite ore subjected to ultrasonic treatment at different time intervals. The purpose of ultrasonic treatment is to remove hard phases such as quartz and calcite from the ore and thereby improve its sorption capacity. The treated samples were thoroughly analysed using SEM and XRD techniques. It was found that increasing the duration of the ultrasonic treatment was associated with a reduction in the proportion of hard phases in the sample. The results of the UV-VIS analysis were also presented, in which the sorption properties of pyrophyllite ultrasonically treated for 30 minutes were investigated in comparison to the sorption properties of the raw ore. The sorption of a methylene blue solution after 24 hours in water was investigated and the UV-VIS analysis showed that the efficiency of the ultrasonically treated pyrophyllite was 97%, while the efficiency of the raw ore was 89% over the same period. These results indicate that the pyrophyllite has good sorption properties and could be a potential material for the production of membranes.Third DIFENEW International Student Conference : 5th December 2023, Novi Sad