Acid-base properties of silicon-containing compounds isolated from horsetails (Equisetum Equisetaceae)

The results of a study into the acid-base surface properties of four silicon-containing ash samples obtained from the above-ground part of the field horsetail plant species (E. arvense L.) are presented. The samples were derived according to various schemes, comprising oxidative roasting both with and without preliminary treatments involving water and solutions of hydrochloric acid having a concentration of 0.1 and 1.0 mol/l. It was shown that the content of silicon dioxide in the samples varies from 33 to 98 % depending on the conditions of processing of raw materials. Preliminary processing of the raw material with an acid solution prior to roasting results in the formation of ash having a high silicon oxide content. The main impurity elements are calcium, potassium, magnesium, aluminum and iron. Samples prepared without preliminary treatment, as well as those treated with water, are characterised by a large amount of alkaline earth metal- and potassium oxides. A comparative characteristic of the surface condition of the obtained ash samples is given using pH measurements and the Hammett acidity function method. The pH measurements allow the integral acidity of the surface to be evaluated, while the Hammett method, based on the selective adsorption of acid-base indicators, is used to study the distribution of surface centres by acid-base properties. The pH values of the aqueous suspensions of neutral, alkaline or acidic samples are determined depending on the plant tissue processing scheme. It was found that the surface of the samples is characterised by the presence of Lewis acid- (pKa +16.8), Brønsted basic- (pKa +7.15; +9.45) and acid- (pKa +2.5) active sites, the amount of which is determined by the composition of the samples. The high content of Lewis acid sites in the ash is associated with silicon atoms. The number of Bronsted sites depends on the horsetail treatment scheme. On the surface of samples obtained by oxidative roasting and those pretreated with water, the number of Brønsted active sites at pKa +2.5 and pKa +9.45 is higher compared to ash isolated following hydrolysis with hydrochloric acid. A comparative characteristic of the distribution curves of acid-base centres of silicon-containing ash samples obtained from the above-ground parts of field horsetail and rice straw is given, indicating their similarity.

1. Sheikh AS. Silicon to silica bodies and their potential roles: An overview // International Journal of Agricultural Sciences. 2014. Sheikh A.S. Silicon to silica bodies and their potential roles: An over-view. International Journal of Agricultural Sciences. 2014;4(2):111–120.

2. Epstein E. Silicon: its manifold roles in plants. Annals of Applied Biology. 2009;155(2): 155–160. https://doi.org/10.1111/j.1744-7348.2009.00343.x

3. Sakr N. Silicon control of bacterial and viral diseases in plants. Journal of plant protection research. 2016;56(4):331–336. https://doi.org/10.1515/jppr-2016-0052

4. Brugiere T, Exley C. Callose – associated silica deposition in Arabidopsis. Journal of Trace Elements in Medicine and Biology. 2017;39:86–90. https://doi.org/10.1016/j.jtemb.2016.08.005

5. Law C, Exley C. New insight into silica deposition in horsetail (Equisetum arvense). BMC Plant Biology. 2011;11:112. https://doi.org/10.1186/1471-2229-11-112

6. Fautex F, Chain F, Belzile F, Menzies JG, Bélanger RR. The protective role of silicon in the Arabidopsis-powdery mildew pathosystem. Proceedings of the National Academy of Sciences of the United States of America. 2006;103(46): 17554–17559. https://doi.org/10.1073/pnas.0606330103

7. Guerriero G, Law C, Stokes I, Moore KL, Exley C. Rough and tough. How does silicic acid protect horsetail from fungal infection? Journal of Trace Elements in Medicine and Biology. 2018;47:45–52. https://doi.org/10.1016/j.jtemb.2018.01.015

8. Zemnukhova LA, Fedorishcheva GA, Egorov AG, Sergienko VI. Recovery conditions, impurity composition, and characteristics of amorphous silicon dioxide from wastes formed in rice production. Russian Journal of Applied Chemistry. 2005;78(2): 319–323. https://doi.org/10.1007/s11167-005-0283-2

9. Zemnukhova LA, Egorov AG, Fedorishcheva GA, Sokol'nitskaya TA, Barinov NN, Botsul AI. Properties of amorphous silica produced from rice and oat processing waste. Inorganic Materials. 2006; 42(1):24–29. https://doi.org/10.1134/S0020168506010067

10. Zemnukhova LA, Panasenko AE, Fedorishcheva GA, Maiorov VY, Tsoi EA, Shapkin NP, Artem'yanov AP. Composition and structure of amorphous silica produced from rice husk and straw. Inorganic Materials. 2014;50(1):75–81. https://doi.org/10.1134/S0020168514010208

11. Della VP, Kühn I, Hotza D. Rice husk ash as an alternate source for active silica production. Materials Letters. 2002;57(4):818–821. https://doi.org/10.1016/S0167-577X(02)00879-0

12. Shen J, Liu X, Zhu S, Zhang H, Tan J. Effects of calcination parameters on the silica phase of original and leached rice husk ash. Materials Letters. 2011;65(8):1179–1183. https://doi.org/10.1016/j.matlet.2011.01.034

13. Lu P, Hsieh Y-L. Highly pure amorphous silica nano-disks from rice straw. Powder Technology. 2012;225:149–155. https://doi.org/10.1016/j.powtec.2012.04.002

14. Witoon T, Chareonpanich M, Limtrakul J. Synthesis of bimodal porous silica from rice husk ash via sol–gel process using chitosan as template. Ma terials Letters. 2008;62(10-11):1476–1479. https://doi.org/10.1016/j.matlet.2007.09.004

15. Zakharova NV, Sychev MM, Korsakov VG, Myakin SV. Evolution of donor-acceptor centers of the surface of ferroelectrics upon dispersion. Kondensirovannye sredy i mezhfaznye granitsy = Condensed Matter and Interphases. 2011;13(1):56–62. (In Russian)

16. Tanabe K. Solid acids and bases. Moscow: Mir; 1973. 184 p. (In Russian)

17. Morrison SR. The chemical physics of surfaces. New York etc., 1977. (Russ. ed.: Morrison SR. Khmicheskaya fizika poverkhnosti tverdogo tela. Moscow: Mir; 1980. 488 p.)

18. Paukshtis EA. Infrared spectroscopy in heterogeneous acid-base catalysis. Novosibirsk: Nauka; 1992. 255 p. (In Russian)

19. Sychev MM, Minakova TS, Slizhov YuG, Shilova OA. Acid-base characteristics of the solids surface and control of the properties of materials and composites. St. Petersburg: Khimizdat; 2016. 276 p. (In Russian)

20. Pakhnutova EA, Slizhov YuG. Acid-base surface properties of gas chromatographic sorbents with grafted layers of metal chelates. Zhurnal fizicheskoi khimii. 2014;88(7-8):1228–1232. (In Russian) https://doi.org/10.7868/s0044453714080226

21. Osipchik VS, Yakovleva RA, Danchenko YuM, Kachomanova MP, Bykov RA, Posokhova IA. Study of the effect of the bentonite surface properties on the curing processes of epoxyamine compositions. Uspekhi v khimii i khimicheskoi tekhnologii. 2007; 21(6):40–43. (In Russian)

22. Thuan FK, Kostromina NV, Osipchik VS. Study of the surface properties of filled composites based on epoxy oligomer. Uspekhi v khimii i khimicheskoi tekhnologii. 2011;25(3):96–101. (In Russian)

23. Sorochkina EA, Smotraev RV, Kalashnikov YuV, Gruzdeva EV. Acid-base surface properties of spherical granular sorbents based on hydrated zirconium and aluminum oxides. Voprosy khimii i khimicheskoi tekhnologii. 2013;6:102–104. (In Russian)

24. Osipchik VS, Kostromina NV, Olikhova YuV, Ivachkina VN, Belyaeva EV, Loginova NA, et al. Study of the influence of modified glass microspheres on the properties of syntactic foams based on oligomethylsiloxane. Plasticheskie massy. 2015;5-6:36–39. (In Russian)

25. Zemnukhova LA, Arefieva OD, Kovekhova AV, Polyakova NV, Panasenko AE, Kamaeva AY. Silicon-containing compounds in horsetail (Equisetum Equisetaceae) composition. Izvestiya Vuzov. Prikladnaya Khimiya i Biotekhnologiya = Proceedings of Universities. Applied Chemistry and Biotechnology. 2019;9(2):159–169. https://doi.org/10.21285/2227-2925-2019-9-2-159-169

26. Antoshkina EG, Smolko VA. Determination of acid-base centers on the surface of quartz sand grains of some Russian deposits. Vestnik Yuzhno-Ural'skogo Gosudarstvennogo Universiteta. Seriya: Matematika, fizika, khimiya. = Bulletin of SUSU. 2008;10(7):65–68. (In Russian)

27. Plekhova EL, Lesishina YuO, Dmitruk AF. Acidic and basic centers of adsorption on the surface of porous carbon materials from phytosources. Nauchnye trudy Donetskogo natsional'nogo tekhhnicheskogo universiteta. Seriya: Khimiya i khimicheskaya tekhnologiya. 2010;14:155–159. (In Russian)

28. Arefieva OD, Borisova PD, Zemnukhova LA Acid-base surface properties of amorphous silica from rice straw. In: Priority areas for the development of science and technology: Proceedings of the XXII International Scientific and Technical Conference. 23 December 2017, Tula. Tula: Innovatsionnye technologii, 2017, p. 17–20. (In Russian)