Analysis of sorption capacity of natural sorbents in relation to aqueous solutions of heavy metal compounds
Abstract
The main preconditions emergence of an environmental crisis in the country due to surface water pollution include irrational use of water resources in violation of the environmental requirements, discharge of untreated and insufficiently treated industrial and municipal wastewater into water bodies and inflow of polluting substances from agricultural lands as a result of surface water drainage. The whole set of considered factors leads to depletion and pollution of surface water of Ukraine, reduction of their self-cleaning capacity, degradation, impoverishment and collapse of aquatic ecosystems.
Excessive content of heavy metal ions in surface water has a negative impact on the environment, causing acute and chronic diseases. Ingress of such pollutants into surface water is almost entirely due to anthropogenic economic activity. Wastewater from chemical, ferrous and nonferrous metallurgy brings a great amount of such pollutants.
Among various methods used for removing heavy metal ions from aqueous media, sorption methods remain one of the most effective and popular, mainly due to the fact that they ensure a high degree of purification at relatively low costs. Along with the adsorbents traditionally involved in these processes, a number of studies and practical implementations with use of natural dispersed minerals as adsorbents were conducted lately.
The research aims at studying the sorption capacity and efficiency of natural and modified sorbent such as bentonite clay for purification of aqueous solutions containing heavy metal ions in the form of dissolved compounds and justifying its potential application.
It studies the efficiency of wastewater treatment aimed at removing heavy metal ions by the natural clay sorbent of bentonite clays of the Cherkaskyi Deposit (Dashukovskyi deposit).
The paper presents a technique for modification of bentonite clay in order to increase its adsorption capacity for heavy metal ions using the following three methods: physical (thermal), chemical (processing with application of Iron(III) chloride solution) and combined (thermal processing of the original sorbent followed by processing with application of Iron(III) chloride solution).
It has been experimentally proved that a natural sorbent modified via thermal and chemical processing is characterized by a high absorption capacity to heavy metal ions contained in water solutions, in particular to chromium(VI) ions, copper(II) ions and aluminum(III) ions with the purification degree ranging from 5% to 83%. The highest adsorption rate, 83%, is demonstrated by the combined method of bentonite clay modification, therefore proving the effectiveness of application of environmentally friendly natural sorbents for wastewater treatment processes aimed at removing heavy metal ions. The paper indicates the advantages of wastewater treatment sorption methods allowing removal of pollutants of different origin and any concentration.
References
Malovanyi, M.S. & Petrushka, I.M. (2012). Ochyshchennia stichnykh vod pryrodnymy dyspersnymy sorbentamy [Wastewater treatment with natural dispersed sorbents]. Lviv: Publ “Lvivska politekhnika”. (in Ukr).
Sakalova, H.V. & Vasylinych, T.M. (2019). Doslidzhennia efektyvnosti ochyshchennia stichnykh vod vid ioniv vazhkykh metaliv z vykorystanniam pryrodnykh adsorbentiv [Study of the effectiveness of wastewater treatment from heavy metal ions using natural adsorbents]. Vinnytsia: The Mykhailo Kotsyubynsky VSPU (in Ukr).
Kovo, G. Akpomie & Folasegun, A. Dawodu. (2015). Potential of a low-cost bentonite for heavy metal abstraction from binary component system. Beni-Suef University. Journal of Basic and Applied Sciences, 4(1), pp. 1-13. https://doi.org/10.1016/j.bjbas.2015.02.002.
Saravanan, D., Gomathi, T. & Sudha, P.N. (2013). Sorption studies on heavy metal removal using chitin/bentonite biocomposite. International Journal of Biological Macromolecules, 53, pp. 67-71. https://doi.org/10.1016/j.ijbiomac.2012.11.005.
Tomáš, Schütz et al. (2016). Cadmium adsorption on manganese modified bentonite and bentonite-quartz sand blend. International Journal of Mineral Processing, 150, pp. 32-38. https://doi.org/10.1016/j.minpro.2016.03.003.
Malyovannyi, Myroslav et al. (2013). Water Sorption Purification from Ammonium Pollution. Chemistry and Chemical Technology, 7(3), pp. 355-358. https://doi.org/10.23939/chcht07.03.355.
Bergaya, F., Theng, B.K.G. & Lagaly, G. (2006). Chapter 1. General Introduction: Clays, Clay Minerals, and Clay Science. Developments in Clay Science, Elsevier, 1, pp. 1-18. https://doi.org/10.1016/S1572-4352(05)01001-9
Rakitskaya, T.L. et al. (2012). Ik-spektralnoe issledovanie struktury i fazovonogo sostava bentonitov Ukrainy [IR-spectral study of the structure and phase composition of bentonites of Ukraine]. Visnik Odeskoho natsionalnoho universitetu. Khimiia [Journal of Odessa National University. Chemistry], 17(1), pp.13-19. (in Ukr).
Brown, G. & Nadeau, P. (1984). Crystal Structures of Clay Minerals and Related Phyllosilicates [and Discussion]. Philosophical Transactions of the Royal Society of London. Series A, Mathematical and Physical Sciences, 311(1517), pp. 221-240
Yanovska E.S. (2008). Naukovi osnovi bezvidkhodnoi tehnolohii doochishchennia promyslovykh stichnykh vod vid sumishei ioniv vazhkykh metaliv. [Scientific bases of waste-free technology of industrial wastewater treatment from mixtures of heavy metal ions]. Ekolohiia dovkillia ta bezpeka zhyttiediialnosti [Ecology of the environment and safety of life], 5, pp. 50-54. (in Ukr).
Taneyeva, A.V. (2017). Analiz sorbtsionnykh kharakteristik sorbentov na osnove bentonitov[Analysis of sorption characteristics of sorbents based on bentonites] Povolzhskiy nauchnyy vestnik [Povolzhsky Scientific Bulletin], 3, pp. 31-36. (in Ukr).
This work is licensed under a Creative Commons Attribution 4.0 International License.
