Study of the Catalytic Activity and Surface Properties of Manganese-Zinc Ferrite Prepared from Used Batteries

Hindawi Journal of Chemistry Volume 2019, Article ID 5430904, 14 pages https://doi.org/10.1155/2019/5430904 Research Article Study of the Catalytic Activity and Surface Properties of Manganese-Zinc Ferrite Prepared from Used Batteries Katarzyna Winiarska ,1 Roman Klimkiewicz ,2 Włodzimierz Tylus,3 Agnieszka Sobianowska-Turek,4 Juliusz Winiarski ,3 Bogdan Szczygieł,3 and Irena Szczygieł1 1 Department of Inorganic Chemistry, Faculty of Engineering and Economics, Wrocław University of Economics, Komandorska 118/120, PL53345 Wrocław, Poland 2 Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okólna 2, PL50422 Wrocław, Poland 3 Department of Advanced Material Technologies, Faculty of Chemistry, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, PL50370 Wrocław, Poland 4 Section of Waste Technology and Land Remediation, Faculty of Environmental Engineering, Wrocław University of Science and Technology, Wybrzeże Wyspiańskiego 27, PL50370 Wrocław, Poland Correspondence should be addressed to Katarzyna Winiarska; Received 21 September 2018; Revised 27 November 2018; Accepted 14 December 2018; Published 16 January 2019 Academic Editor: Barbara Gawdzik Copyright © 2019 Katarzyna Winiarska et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The catalytic activity of the Mn-Zn ferrites obtained by chemical methods from a solution after acid leaching of waste Zn-C and Zn-Mn batteries was studied. Precursors of metal ions (Fe, Mn, and Zn) were obtained using different precipitating agents ((NH4)2C2O4, Na2CO3, and NaOH), and then, the combustion route was used to prepare catalytically active nanocrystalline ferrites. The obtained ferrite catalysts differ in terms of microstructure, the number of acid and base sites, and the surface composition depending on the ion precursor used in the combustion process. All prepared materials were catalytically active in the butan-1-ol conversion test. Depending on the ion precursor applied in the combustion process, a selective catalyst towards aldehyde (carbonate precursor) or ketone (hydroxide precursor) formation can be obtained. Furthermore, the catalyst prepared from the hydroxide precursor exhibits the highest catalytic activity in the n-butanol test (nearly 100% conversion under the experiment conditions). 1. Introduction One of the significant aspects of waste management is the recycling of worn out batteries and accumulators. The main aim of the battery industry is to reduce the negative impact of the used batteries, accumulators, and other portable cells on the environment by reducing the amount of hazardous substances in batteries and accumulators and enabling the proper collection and recycling of battery waste. Due to the existing regulations and the increasing amount of battery and accumulator waste, new technologies for the recycling of used cells, or modifications of existing methods, are being sought. The processing methods are mainly based on pyrometallurgical or hydrothermal processes [1–3]. Recently, there have been many scientific studies focused on improving the efficiency of the hydrometallurgical recovery of zinc and manganese from battery waste by using additional reducing agents (e.g., oxalic acid or urea) in the sulphuric acid (VI) leaching process [4, 5], the selective leaching of zinc with sodium hydroxide [6], or leaching with a mixture of sulphuric acid or ammonia with the addition of SO2 [7]. Besides the studies on the recovery of Zn, MnO2, or ferromanganese alloy from Zn-Mn and Zn-C batteries [5–9], there are also studies on the processing of battery waste by chemical methods leading to prepared Mn-Zn ferrites, soft magnetic materials commonly used in microelectronics. In 2 this case, used batteries were subjected to mechanical crushing and then leached with sulphuric acid [10, 11], hydrochloric acid [12], or nitric acid [13, 14]. Ferrite can be prepared from such solutions by co-precipitation [15–17], when sodium hydroxide or ammonium oxalate is used as a precipitating agent. Attempts to synthesise ferrite powders by combustion methods in the presence of citric acid as a fuel and nitrate ions (derived from nitric acid leaching of crushed battery waste) as an oxidant have also been described [13, 14, 18]. The studies [13, 14, 18] were focused on determining the degree of leaching of Mn, Zn, and Fe, the main components of ferrite (the content of the other elements in the solution after leaching was not studied), after which the microstructure and phase composition of the obtained products were characterised. Nan et al. [10] and Kim et al. [16] also investigated the magnetic properties of the ferrites prepared from waste batteries and found that the saturation magnetization of the powders obtained by coprecipitation from the solution after leaching battery scrap is similar to that of Mn-Zn ferrites synthesised by other chemical methods. Cheng-hong et al. [11] described the MnZn ferrite prepared from battery waste with magnetic properties that were not much worse than those of typical ferrites produced on a large scale by a ceramic method. The effect of the precipitating agent on magnetic and thermal properties was also studied in [19]. Simultaneously, the recent literature points to new potential application areas of ferrite synthesised by chemical methods from pure reagents, such as adsorbents [20], catalysts [21–23], gas sensors [24], drug delivery [25], and in thermotherapy of cancers [26–28]. Ferrite powders of a metastable character can be obtained by low-temperature synthesis and can be used in catalysis due to their high reactivity/activity [29, 30]. Based on our previous studies conducted on model systems, we found that the prepared Mn-Zn ferrites are catalytically active in the test of butan-1ol conversion [23, 31]. However, there are no data on the catalytic activity of such materials derived from secondary sources. In this study, Mn-Zn ferrites were prepared by coupled co-precipitation and combustion methods from solutions after the acid leaching of battery waste. The method proposed in this paper, Mn-Zn ferrite synthesis, is an attempt to broaden the technology of processing battery waste by hydrometallurgical methods. A careful analysis of the microstructure and surface condition with regard to acid-base properties and redox centres allowed the differences in the catalytic activity of the prepared materials to be discovered and explained. 2. Materials and Methods 2.1. Mn-Zn Ferrite Preparation. The procedure of leaching Zn-C and Zn-Mn battery scraps was described in detail in [4, 32]. The quantity and quality of metal ions in the solution after leaching (determined by ICP-AES) are shown in Table 1. The sulphate solution after leaching was a source of metal ions in the subsequent st (...truncated)