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1

Comparison of hydrogel- and xerogel-based sorbent from Empty Fruit Bunch (EFB)

Alias A.B., Qarizada D., Malik N.S.A., Noraini N.M.R., Rashid Z.A.

Archives of Materials Science and Engineering

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2022

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Vol. 118, nr 2

49--60

EN

Purpose: This paper focuses on the synthesis and comparison of hydrogel- and xerogel-based sorbents from EFB. Design/methodology/approach: Hydrogels were synthesised by polymerisation of EFB biochar with acrylamide (AAm) as a monomer, N, N'-Methylenebisacrylamide (MBA) as cross-linker and ammonium persulfate (APS) as initiator, as well as by internal gelation method of sodium alginate, empty fruit bunch (EFB), calcium carbonate (CaCO3), and glucono delta-lactone (GDL). From the alginate hydrogels obtained, xerogels were synthesised via the oven-drying method. Then, EFB-based hydrogel and xerogel sorbents were analysed and compared based on characterisation analysis by using scanning electron microscopy (SEM), Brunauer− Emmett−Teller (BET), Fourier-Transform Infrared Spectroscopy (FTIR), and thermogravimetric analysis (TGA). Findings: The xerogel-based EFB is a better adsorbent than the hydrogel-based EFB because it has a larger pore volume (0.001449 cm3/g), larger pore size (63.7987 nm), higher moisture content (7.97%), lower ash content (12.55%), and is more thermally stable. Research limitations/implications: The research is to compare two new adsorbents, namely Hydrogel and Xerogel, from EFB in terms of their characteristics. Practical implications: Both adsorbents show a highly toxic material uptake, especially EFB xerogel. This adsorbent is comparable with the other commercialised adsorbent. Thus, this product can be a highly potential adsorbent for gas and wastewater adsorption. Originality/value: The authenticity results of this article were found to be 15% similar. The novelty of this paper is to compare the two adsorbents, namely hydrogel and xerogel, that originated from EFB.

2

Mesoporous magnesium oxide xerogels : synthesis and structural characteristics

Malinowski Janusz, Pudło Wojciech

Prace Naukowe Instytutu Inżynierii Chemicznej Polskiej Akademii Nauk

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2021

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nr 25

33--43

EN

The paper presents the results of a study on the synthesis of magnesium oxide xerogels. In the synthesis, the sol-gel method was used, in which magnesium methoxide was applied as a magnesium precursor. The obtained magnesium hydroxide was subjected to the thermal dehydration process to obtain magnesium oxide particles. The influence of xylene addition during magnesium methoxide hydrolysis on the structure of the magnesium hydroxide and oxide was investigated.

PL

W pracy przedstawiono wyniki badań nad syntezą cząstek kserożeli tlenku magnezu. W procesie syntezy zastosowano metodę zol-żel, w której wykorzystano metanolan magnezu jako prekursor tlenku magnezu. Otrzymany wodorotlenek magnezu poddano procesowi termicznej dehydratacji w celu otrzymania tlenku magnezu. Zbadano wpływ dodatku ksylenu na strukturę wodorotlenku i tlenku magnezu.

3

Nanocoat Finishing of Polyester/Cotton Fabrics by the Sol-Gel Method to Improve their Wear Resistance

Brzeziński S., Kowalczyk D., Borak B., Jasiorski M., Tracz A.

Fibres & Textiles in Eastern Europe

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2011

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Vol. 19, no. 6 (89)

83--88

EN

A serious drawback of the commonly used textiles of polyester/cotton fibres blends (PET/CO), especially those containing worse cotton brands, is their great susceptibility to form pilling, which adversely affects their performance durability and aesthetic values. Among the many methods of preventing this phenomenon, the thin-coating finishing performed by sol-gel methods provides interesting possibilities in this field. By a proper selection of precursors and synthesis method as well as the deposition of sols, it is possible to form xerogel coats on the fibre surface characterised by considerable hardness and abrasion resistance, thus reducing the formation of pilling, without any deterioration in the aesthetic values of textiles. Moreover, these coatings are strongly combined with the fibre surface and are resistant to the conditions of use and care, including multiple washing processes. The thin-coat finishing of this type also increases the abrasion resistance of textiles with a dominating content of polyester fibres, and thus it positively influences the performance value of textile fabrics. This paper presents the test results of using the hybrid modified SiO2/Al2O3 sol developed, synthesised with the use of two precursors: (3-glycidoxypropyl) trimethoxysilane (GPTMS) and aluminium isopropoxide (ALIPO), and the conditions of its application to the thin-coat finishing of PET/CO (67:33) woven fabrics were selected to increase their abrasion resistance and prevent the formation of pilling. Consequently, the fabric susceptibility to form pilling was practically completely eliminated (assessment at level 5 according to the Martindale test), and the fabric abrasion resistance was increased by 38%, with the effects obtained being resistant to prolonged laundering.

PL

Istotną wadą tekstyliów z mieszanek włókien poliestrowych i bawełnianych jest ich duża skłonność do tworzenia pillingu, co negatywnie wpływa na trwałość użytkową oraz cechy estetyczne wyrobów. Wśród wielu sposobów przeciwdziałania tej skłonności, duże możliwości stwarza wykończenia nanopowłokowe metodą zol-żel. W rezultacie prowadzonych badań ustalono, że w wyniku odpowiedniego doboru prekursorów i addytywów oraz opracowanych metod syntezy, a następnie włókienniczej aplikacji zoli, można wytwarzać na powierzchniach włókien cienkie powłoki kserożelowe, które nie powodując pogorszenia cech estetycznych tekstyliów, jednocześnie istotnie zwiększają odporność tkanin na ścieranie, a więc i mechacenie, a w rezultacie na tworzenie pillingu. Powłoki takie są silnie związane z powierzchniami włókien i odporne na warunki użytkowania i konserwacji wyrobów, w tym wielokrotne prani

4

Structure studies on nanocrystalline powder of MgO xerogel prepared by the sol-gel method

Dercz G., Prusik K., Pajak L., Pielaszek R., Jmalinowski J. J., Pudlo W.

Materials Science Poland

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2009

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Vol. 27, No. 1

201--207

EN

Structure studies were performed on nanocrystalline powder of MgO xerogel prepared by the sol-gel technique, producing high purity, chemically homogeneous materials of relatively high specific surface area. Magnesium methoxide was used as an MgO precursor. The wet gel was dried under conventional conditions, yielding xerogel with periclase phase; the only crystalline form of magnesium oxide. The X-ray diffraction, scanning and transmission electron microcopies were used as the tools of structure analysis. The Toraya PRO-FIT procedure and the Rietveld refinement method were applied for X-ray data analysis. Both techniques apply the Pearson VII function for the description of line profiles. The gamma crystallite size distribution was determined using the FW(1/5)/(4/5)M method proposed by Pielaszek. The obtained values of and ? (measure of polydispersity) of particle size parameters are equal to 7.1 nm and 2.1 nm, respectively, whereas the average crystallite size, estimated by the Williamson- Hall procedure, was equal to 7.5 nm. The Rwp, and S fitting parameters obtained from the Rietveld refinement were equal to 6.4% and 1.8, respectively. This would seem the most satisfactory result, when considering the nanosize of MgO crystallites and a very probable presence of amorphous phase.

5

Charakterystyka, procesy chemicznej modyfikacji oraz zastosowanie krzemionki i jej zmodyfikowanych postaci

Kupiec K., Konieczka P., Namieśnik J.

Chemia i Inżynieria Ekologiczna

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2007

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Vol. 14, nr S4

473-487

PL

Różnorodność chemicznych modyfikacji powierzchni krzemionki i jej zmodyfikowanych postaci powodują, iż materiały te znajdują coraz szerszy zakres wykorzystania. W artykule przedstawiono charakterystykę krzemionki, żelu krzemionkowego, aerozolu oraz kserożelu. Omówiono otrzymywanie, zastosowanie, a także właściwości tych materiałów. Przedstawiono sposoby chemicznej modyfikacji struktur powierzchniowych z użyciem różnych związków, chemicznych. Szczególną uwagę zwrócono na zachowanie się krzemionki i jej zmodyfikowanych postaci podczas procesu adsorpcji. Omówiono także główne zastosowania krzemionki i jej postaci w analityce chemicznej.

EN

The diversity of chemical modifications of surface silica and its modified forms cause that these materials arc finding a wider range of applications. In the publication. silica characteristics are presented, as well as those of silica gel and xerogel. The obtainment, applications and properties of these materials are discussed. Methods of chemical modifications of the surface structures arc presented, with the utilization of different chemical compounds. Specific attention is turned to silica storage and the modification of its form during the adsorption process. The main applications of silica and its form in analytical chemistry ale also discussed.

6

EPR studies of defects in pure sol-gel matrices and their influence on cytotoxicity of the material

Ulatowska-Jarża A., Komorowska M., Podbielska H.

Materials Science

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2003

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Vol. 21, No. 4

487-494

EN

Sol-gel based biomaterials may be used for various applications, including biomedical ones. In his respect it is important to investigate the influence of sol-gel matrices on biological systems in order to establish their cytotoxic activity. The results of EPR studies of sol-gels are described in this work. They demonstrate that various defects are present in sol-gel matrices: surface defects, peroxy- centres or hydrogen-related centres. These defects arise spontaneously during the gelation, being responsible for cytotoxicity of sol-gels. It was found that the ratio of the number of solvent moles to the number of prekursor moles (the molar ratio R) is one of the factors determining the level of cytotoxicity. More defects were present in samples prepared with a lower molar ratio R. A higher concentration of defects was detected in freshly prepared samples, as compared to samples aged for a longer time.

7

Luminescent materials, recognition phases of the chemical sensors and heterogeneous catalysts prepared by sol-gel method

Kłonkowski A. M.

Materials Science

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2002

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Vol. 20, No. 1

57-70

EN

The sol-gel process enables one to prepare oxide xerogels at room temperature. By using this method, it is possible to encapsulate a wide variety of organic, complex (organometallic) molecules and metallic nanoparticles stabilized by organic ligands in the inorganic or inorganic/organic hybrid matrix. Studies of this new type of inorganic/organic composite have evolved towards the deliberate doping of the supramolecular species. This review gives three examples of how doped xerogel materials prepared by the sol-gel method are emerging as an important means of producing new materials. The first part of this review is devoted to luminescent materials which are based on the antenna effect and are composed of Eu(III) complex (luminescence centre) entrapped in xerogel matrix. In this case results of the experiments concerning the coordination sphere composition show that a cryptand ligand with aromatic groups and an aromatic co-ligand, settle efficient action the antenna effect and isolate the central ion from each efficient quenchers, as e.g. water molecules. Secondly, silica xerogel samples with entrapped series of three fluorescent chemosensors of the Ant-R-Ant type, where Ant is an anthryl group and R is a receptor (spacer) with donor atoms, were prepared as chemical recognition phases. The recognition phase with fluorosensor of the type Ant- N-O-O-N-Ant, where N and O are donor atoms, can be regenerated many times and seems to be most promising system for the fluorescent chemical sensor. In the third part of this paper, ligand protected metal nanoclusters as immobilized catalysts are the point of interest. This type of heterogeneous catalysts are much less investigated than the bare metal particles on supports. The main interest is focused on the function of the ligands.

8

Tendencje w inżynierii materiałów mezoporowatych. Implikacje dla inżynierii procesowej

Jarzębski A. B., Mrowiec-Bialoń J.

Inżynieria Chemiczna i Procesowa

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2001

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T. 22, z. 3A

55--63

PL

Przedstawiono tendencje dominujące w inżynierii materiałów mezoporowatych. Omówiono zasady otrzymywania nowoczesnych materiałów o strukturze nieuporządkowanej (aerożele, kserożele) i uporządkowanej, w szczególności różnych typów mezoporowatych, tlenkowych sit i pianek otrzymywanych z wykorzystaniem ciekłokrystalicznych szablonów lub mikroemulsji.

EN

Recent trends predominating in the engineering of mesoporous materials are presented. The preparation of materials exhibiting both an ordered and disordered structure in mesoscopic scales is discussed, with the focus placed on aerogels, xerogels, mesoporous sieves and foams obtained with the use of different organic or microemulsion templates.