New Electrodes Prepared from Mineral and Plant Raw Materials of Kazakhstan

Abstract

<p>Electrode materials were prepared from activated carbonizates of walnut shell, apricot pits and shungite rock from “Bakyrchik” deposit, East Kazakhstan. Physicochemical characteristics of the obtained samples were studied by the Brunauer-Emett-Taylor method, scanning electron microscopy, Raman spectroscopy and other methods. Electrochemical properties of the obtained materials were studied by the method of cyclic voltammetry. It was found that the samples have an amorphous structure. Samples based on plant raw materials after hydrothermal carbonization at 240 °С during 24 h, have more homogeneous and developed surface. Specific surface area of carbon containing materials based on apricot pits is 1300 m<sup>2</sup>/g, for those on the based on mineral raw material, it is 153 m<sup>2</sup>/g. It was shown that materials after hydrothermal carbonization can be used for catalytic purposes and electrodes after thermal carbonization for analytical and electrocatalytic purposes. Electrode obtained by HTC have electrocatalytic activity. CSC 240 has high background current (slope i/Е is 43 mА V<sup>–1</sup> cm<sup>–2</sup>), low potential of the hydrogen electroreduction (more positive by ~ 0.5 V than samples based on plant raw materials). The reaction of DA determination is more pronounced on the electrodes obtained by HTC 240 °C, 24 h, due to the nature, carbon structure and high specific surface area of obtained samples.</p>

Functional Activated Biocarbons Based on Biomass Waste for CO2 Capture and Heavy Metal Sorption

“…Differences in the pore sizes can be related to the decomposition of organic compounds during the process of activation and the nature of the carbon skeleton. A large amount of organic compounds in the samples after HTC, apparently, increases the number of pores created in the time of activation …”

Study of the Potential Uses of Hydrochar from Grape Pomace and Walnut Shells Generated from Hydrothermal Carbonization as an Alternative for the Revalorization of Agri-Waste in Chile

“…HTC modified the elemental make-up of hydrochar marginally, most notably the H/C and O/C ratios, which may have confirmed the carbonization degree of the hydrochar. Furthermore, the mass loss is highly dependent on the severity of the reaction and the biomass composition [57,73]. Table 3 displays the elemental composition of hydrochar.…”

“…Several studies have been conducted related to the waste generated by the wine industry [37][38][39][40][41], along with numerous studies describing the potential of walnut shells [42][43][44][45][46][47][48]. More specifically, walnut shell and grape pomace have received great attention regarding HTC processing to study a myriad of variables, such as residence time, temperature, and biomass-water ratio, obtaining results that help to determine the potential use that can be given to the waste, being reused, and preventing it from being considered solely as a waste but as a bioresource [14,16,[49][50][51][52][53][54][55][56][57][58][59].…”

Shungite (Mineralized Carbon) as a Promising Electrode Material for Electroanalysis

“…Despite all other characterization studies [ 12 , 13 , 14 ], no scientific research has yet focused on a detailed study of the electrochemical properties of shungite. Therefore, there is a strong motivation to elaborate a study in which “home-made” solid-disk working electrodes are manufactured from two types (noble elite and black raw) of shungite stones and then subjected to electrochemical study, including a comparison with the most widely used and commercially available solid-disk glassy carbon electrode (GCE).…”