Chloride Salts of Triethyl- and Benzyl-Triethyl-Ammonium: A New Antifungal for Giant Bamboo (Dendrocalamus asper) Preservation

In this study, quarternary ammonium salts based on triethylammonium and benzyltriethylammonium cations with the anion of chloride are successfully used for giant bamboo (Dendrocalamus Asper) preservation. These salts are new biocides as well as new salts which penetrate bamboo well. The prepared salts with hydrogen and benzyl substituent at the cation and consisted of chloride anion, exhibited fungicidal activity against Aspergillus Flavus. The effective and lethal doses were measured by the agar-plate method. In their activity against bamboo degrading fungi, salt of benzyl-triethyl-ammonium chloride was comparable with commercially available benzalkonium chloride and didecyldimethylammonium. Keywords: Triethylammonium, Benzyltriethylammonium, chloride, antifungal, and giant bamboo (Dendrocalamus Asper) and Aspergillus Flavus

Comparative Study on Lipase Immobilized onto Organo-Cation Exchanged Kaolin and Metakaolin: Surface Properties and Catalytic Activity

Clay mineral has received much attention to be used as biocatalysts as it is cheaper, easily available and environmentally friendly. However, the use of unmodified clay, in particular kaolin for enzyme immobilization showed unsuitability of this support due to its negative charge. In this study, the hydrophobic properties of kaolin and metakaolin (kaolin heated to 650 °C) were adjusted by the intercalation with benzyltriethylammonium chloride (BTEA-Cl), at concentrations 2.0 times the cation exchange capacities (CEC) of the clays. The supports were then used for immobilization of lipase from Candida rugosa (CRL). From the study, the highest percentage of lipase immobilization was achieved (70.14%), when organo-modified metakaolin (2.0 MK) was used. The supports as well as the immobilized biocatalysts were then characterized by X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy, and nitrogen adsorption techniques. Comparisons of the efficiencies of immobilized with free CRL in the synthesis of nonyl hexanoate showed that immobilized CRL achieved enzymatic activities of between 5.24×10−3 to 3.63×10−3 mmol/min/mg, while free CRL achieved enzymatic activity of 3.27×10−3 mmol/min/mg after 5 h of reaction at 30 ℃. The immobilized CRLs also maintained 70.81% – 80.59% thermostabilities at 70 ℃ as compared to the free CRL (28.13%). CRL immobilized on 2.0 NK and 2.0 MK also maintained 38.54% and 62.56%, respectively, of the initial activities after 10 continuous cycles, showing the excellent stability and reusability of the immobilized lipases, suitable as substitute for expensive, hazardous catalysts used in industries. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

Sorption of potential ionic pollutants on oil shale and its non-series composite sorbents

Huge amounts of anthropogenic environmental pollutants appearing in nature mean an emerging problem. Oil shale is a convenient candidate, wherewith these contaminations can be removed from our natural environment, taking into account its sorption ability and low price. However, oil shale has a crumbling nature, which restricts its facile usage. Hence, oil shale was transformed into more handleable forms, using binding materials. Two oil shale composite forms were prepared by applying sodium alginate and agar. A cationic and an anionic chemicals, benzyltriethylammonium chloride and sodium 2,3-diisopropylnaphthalene-1-sulfonate, respectively, were used as model pollutants, and their sorptions on these newly prepared composites were studied. Sorption properties of oil shale powder and oil shale composites were compared. In the composite materials, oil shale properly sorbed the model pollutants (the binding material did not cover the sorption sites); furthermore, oil shale composites had significantly higher removal efficiency compared to that of the oil shale powder: 208 ± 15.6 (oil shale–agar) and 171 ± 22.8 (oil shale–alginate) vs 140 ± 11.1 µmol/g for the cationic compound; 151 ± 1.6 (oil shale–agar) and 165 ± 7.6 (oil shale–alginate) vs 81.5 ± 2.6 µmol/g for the anionic compound. Results of diffusion models for the two composites show that the opposite charges of the solutes largely influence the rate of their diffusion, owing to the interaction between the solute and the composite material. These results indicate that oil shale and its composites are applicable candidates as sorbents, from which the most effective one can be chosen by considering the chemical properties of the actual pollutant to be removed.

Modification of kaolinite clay using benzyltriethylammonium chloride as a surfactant: Preparation and characterization

Natural kaolinite clay from Perak, Malaysia with cation exchange capacity (CEC) of 2.5 meq/100g was modified using cationic surfactant, benzyltriethylammonium chloride (BTEA-Cl), at 0.5, 1.0, 1.5 and 2.0 times the CEC. A number of techniques, namely energy dispersive X-ray (EDX) spectroscopy, X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) nitrogen adsorption-desorption were then used for characterization of the kaolinite and/or organo-modified kaolinite clays. The presence of alkyl groups as a result of successful intercalation of cationic surfactant within the organo-kaolinite layers of the clay was exhibited by the FTIR spectra. The SEM microphotographs exhibited good dispersion of the natural clay particles and slight agglomeration in the organo-modified clay particles. XRD patterns showed that the d001 spacing of the natural kaolinite clay increased from 7.12 Å to between 7.20 - 7.34 Å for the organo-modified clays. Following the BET nitrogen adsorption-desorption technique, all clay samples were of Type IV with narrow hysteresis loops. Surface areas of the clays showed drastic decrease from (25.34 m2/g) for natural kaolinite clay to between 5.90 - 13.11 m2/g for organo-modified clays. The results suggested that modification of natural kaolinite clay using cation surfactant had successfully occurred. The modification can therefore be further applied for alteration and improvement of the properties of natural clays for various industrial applications.

Real-time and selective detection of nitrates in water using graphene-based field-effect transistor sensors

A benzyltriethylammonium chloride-modified graphene field-effect transistor sensor has high sensitivity, high selectivity and rapid response for nitrate detection.