Electrocatalytic Activity of Pd/Ir/Sn/Ta/TiO2 Composite Electrodes

Park, Jung Eun; Yang, Seung Kyu; Kim, Ji Hyun; Park, Mijung; Lee, Eun Sil

doi:10.3390/en11123356

Cited by 4 publications

(8 citation statements)

References 30 publications

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“…A commercial electrode, 8.6 g Pd-Ir-Sn-Ta/TiO 2 , was purchased from West Co. (Changwon-si, Korea) and the substrate was an aluminum plate. The metal composition was obtained using energy-dispersive X-ray analysis (EDAX, Inspect F50, Thermo Fisher Scientific, Waltham, MA, USA) and the electrode compositions of Pd, Ir, Sn, and Ta were 8.6, 39.9, 18.5, and 33.0% [23]. The thickness of coating materials was 7.6~8.8 um and is well dispersed, as shown in Figure 1b,c.…”

Section: Characterization Of Electrodesmentioning

confidence: 99%

Adsorption Capacity of Organic Compounds Using Activated Carbons in Zinc Electrowinning

Park

Kim

Park³

et al. 2019

Energies

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The influence of adsorbate (D2EPHA and kerosene) on the process of zinc electrowinning from sulfuric acid electrolytes was analyzed. The main objective was to critically compare three factors: (1) Three types of activated carbon (AC); (2) adsorption temperatures and contact time; and (3) zinc recovery efficiency. The results showed that organic components reduced the efficiency of zinc recovery. Moreover, wood-based ACs had a higher adsorption capacity than coal-and coconut-based ACs. To maintain a removal efficiency of 99% or more, wood-based ACs should constitute at least 60% of the adsorbate. The temperature of adsorption did not affect the removal efficiency. Additionally, the feeding rate of adsorbate in the solvent was inversely proportional to the removal efficiency. A feeding rate of the liquid pump of over 3 mL/min rapidly increased the delta pressure. For the same contact time, 99% of adsorbate removal occurred at 1 mL/min compared to approximately 97% at 0.5 mL/min. In the presence of 100 mg/L zinc, with increasing adsorbate from 0-5%, the recovery efficiency of zinc decreased from 100% to 0% and the energy consumption increased from 0.0017-0.003 kwh/kg zinc. Considering the energy consumption and zinc deposit mass, 0.1% of the adsorbate is recommended for zinc electrowinning.The presence of organophosphorus-based extractants decreases metal impurities, including the concentration of Zn [17]. Ivanov's research group focused on Zn impurities through the addition of inhibitors during electrowinning [18,19]. They reported that the addition of inhibitors to the electrolytes caused Zn re-dissolution. For this reason, it is necessary to explore effective methods for the efficient removal of organic components in sulfuric acid solvent components to improve the Zn electrowinning process. The adsorption of organic components from sulfuric acid by carbon has been studied for several decades and is becoming more widespread, due to large surfaces and strong adsorption [19][20][21][22]. Hydrophobic carbons are more effective adsorbents for trichloroethene (TCE) and methyl tertiary-butyl ether (MTBE) than hydrophilic carbons because enhanced water adsorption on the latter interferes with the adsorption of micropollutants from solutions containing natural organic matter [22]. Among all types of carbon, activated carbon (AC) is generally considered to have a strong adsorption affinity for organic chemicals, due to their highly hydrophobic surfaces. With respect to pore structure, optimal AC should exhibit a large volume of micropores approximately 1.5 times the kinetic diameter of the target adsorbate [22].Therefore, in order to determine an efficient removal method of organic components in sulfuric acid solvent components, it is necessary to determine the uppermost limit of organic compounds that will not affect the Zn electrowinning efficiency. Therefore, this study has three principle objectives:(1) To compare the performance of three types of AC as an adsorbent; (2) to investigate the effects of adsorption tempera...

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Section: Characterization Of Electrodesmentioning

confidence: 99%

Adsorption Capacity of Organic Compounds Using Activated Carbons in Zinc Electrowinning

Park

Kim

Park³

et al. 2019

Energies

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“…In addition, Pd was added at 2, 4, 8 and 10 wt.%. The Pd-IrSnTa/TiO 2 electrode contained PdO x , IrO x , SnO x and TaO x on a TiO 2 substrate [26,27]. The surface texture and morphology of the Pd-based electrode was characterized using a Field Emission Scanning Electron Microscope (FE-SEM), equipped with an energy dispersive spectrometer (EDS), which was acquired using a Regulus 8230 (HITACHI instrument, Tokyo, Japan) that worked with an acceleration voltage of 10 kV.…”

Section: Electrodesmentioning

confidence: 99%

“…The electrochemical behavior of the electrodes was tested on a ZIVE electrochemical workstation (WBCS3000M2) from Won-A Tech. (Seoul, Korea) using a two-electrode system [26,27]. The reactor system was a batch reactor, and there was a reactor volume of 2.0 L for each electrode, as shown in Figure 1.…”

Section: Accelerated Life Testing (Alt)mentioning

confidence: 99%

Accelerated Life Testing of a Palladium-Doped Tin Oxide Electrode for Zn Electrowinning

2020

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Electrowinning is a technique that can be used to obtain high-purity elements through electrolysis. The degradation of accelerated life testing for Pd-based electrodes is discussed in this study. The lifetime of the electrodes was examined by multiplying the acceleration rate with the current to measure the voltage of the electrodes. The acceleration rate was set to 10, 20, and 30 times. Four components were deposited on the TiO 2 plate. The ratio of Ir to Sn was fixed at 1:1, while Ta was deposited at 10 wt.%. Pd was deposited at 2, 4, 8 and 10 wt.% to create Pd-Ir/Sn-Ta. The initial voltage decreased as the Pd deposition amount increased irrespective of the acceleration rate. The lower the acceleration rate, the lower the voltage. An increase in the Pd content caused the initial voltage to be low. The multiple of the acceleration rate slightly increased for all cases of life testing for one year. When the test was conducted by increasing the current density by 20 times, the increase in voltage was proportional to the Pd deposition amount. However, for the 30 times acceleration rate, the lifetime of the electrodes was shortened as the Pd content increased. It can be inferred that the content of Pd and the ratio of Ir to Sn can influence the lifetime of the electrodes. According to these results, if the multiple of the acceleration rate is too extreme, the lifetime of the electrodes cannot be evaluated because they are damaged in an extreme situation.feasibility. In particular, many studies have been conducted on metal compositions; however, most of these investigations focus on simple compositions or characteristics of the electrodes [15,16].Electrowinning is typically conducted within 48 h when considering the current efficiency and zinc recovery efficiency, in which the electrodes are reused several times. These electrodes, with a high rate of reusability, are provided with a low power consumption in the electrowinning process. When a purified solution undergoes direct electrowinning, the purity of zinc ingot, which is the final product, may be reduced due to various metal substances (excluding zinc) in the purified solution. Therefore, the process of extracting zinc alone from a purified solution and then proceeding with electrowinning is gaining attention. Zinc is then dissolved in sulfuric acid. If the electrodes are exposed to highly concentrated sulfuric acid for an extended period of time, substances coated on the electrodes detach, and zinc recovery is hindered. In addition, the power consumption is increased due to the increased voltage. Thus, the lifetime of electrodes is very important in the electrowinning process [17][18][19].For electro refining, an excellent electrode must be able to work efficiently for several years. However, testing the electrode stability under normal conditions is time consuming. The lifetime of the electrode is one of the most important factors for the stability of the electrode [20]. Generally, the researcher compared the service life with different compositions of electro...

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“…Insoluble catalysts include IrOx, PdOx, TaOx, and SnOx, where IrOx and PdOx are used as activators to improve the current efficiency, while TaOx and SnOx are used as a stabilizer and dispersant, respectively, to increase the electrode’s lifespan [9,10,11,12,13]. For example, in a IrOx/Ti electrode, Mn in the electrolyte is electrodeposited in an oxide form at the cathode surface to increase cell resistance, while F ions corrode the coated catalyst at the cathode surface, critically reducing the electrode efficiency and lifespan [14]. To improve the electrodes, TaOx–SnOx–PdOx oxides can be added as the main catalysts for the IrOx electrode to increase the electrode’s lifespan and current efficiency compared to an IrOx/Ti electrode [14].…”

Section: Introductionmentioning

confidence: 99%

“…For example, in a IrOx/Ti electrode, Mn in the electrolyte is electrodeposited in an oxide form at the cathode surface to increase cell resistance, while F ions corrode the coated catalyst at the cathode surface, critically reducing the electrode efficiency and lifespan [14]. To improve the electrodes, TaOx–SnOx–PdOx oxides can be added as the main catalysts for the IrOx electrode to increase the electrode’s lifespan and current efficiency compared to an IrOx/Ti electrode [14].…”

Section: Introductionmentioning

confidence: 99%

Zinc Recovery through Electrolytic Refinement Using Insoluble Ir + Sn + Ta + PdOx/Ti Cathode to Reduce Electrical Energy Use

2019

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In this study, an alumina (Al) anode, a lead cathode, and insoluble catalytic cathodes (IrOx, PdOx, TaOx, and SnOx) were used as electrodes to enhance zinc recovery. The traditionally used iron electrode and insoluble catalytic electrodes were also used to compare the recovery yield when different types of electrodes were subjected to the same amount of energy. The lead electrode showed over 5000 Ω higher electrode resistance than did the insoluble catalytic electrode, leading to overpotential requiring higher electrical energy. As electrical energy used by the lead and the insoluble catalytic electrodes were 2498.97 and 2262.37 kwh/ton-Zn, respectively, electrical energy can be reduced by 10% when using an insoluble catalytic electrode compared to that when using a lead electrode. Using recovery time (1–4 h) and current density (100–500 A/m2) as variables, the activation, concentration polarization, and electrode resistance were measured for each condition to find the optimum condition for zinc recovery. A recovery yield of about 77% was obtained for up to 3 h of zinc recovery time at a current density of 200 A/m2, which is lower than that (about 80%) obtained at 300 A/m2. After 3 h of recovery time, electrode resistance (Zn concentration reduction, hydrogen generation on electrode surface) and overpotential increase with time decreased at a current density of 200 A/m2, leading to a significant increase in zinc recovery yield (95%).

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Electrocatalytic Activity of Pd/Ir/Sn/Ta/TiO2 Composite Electrodes

Cited by 4 publications

References 30 publications

Adsorption Capacity of Organic Compounds Using Activated Carbons in Zinc Electrowinning

Adsorption Capacity of Organic Compounds Using Activated Carbons in Zinc Electrowinning

Accelerated Life Testing of a Palladium-Doped Tin Oxide Electrode for Zn Electrowinning

Zinc Recovery through Electrolytic Refinement Using Insoluble Ir + Sn + Ta + PdOx/Ti Cathode to Reduce Electrical Energy Use

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