윤석표 Seok-pyo Yoon

DOI:10.9786/kswm.2025.42.1.1

Abstract

This study reviews academic papers on lithium-ion battery (LIB) waste recycling technologies, covering pre-treatment processes such as discharge, disassembly, and crushing of wasted batteries; hydrometallurgy and pyrometallurgy; life cycle assessment of battery recycling processes; and the generation and treatment/disposal of sulfate-rich wastewater. By 2030, the disposal of LIBs from electric vehicles is expected to increase significantly. In response, several areas require technological development and the establishment and activation of related industrial ecosystems in LIB recycling: 1) Constructing a stable supply system for the “black matter”, the target recycling material; 2) Developing and applying automated and safe disassembly techniques for battery dismantling using AI technology; 3) Creating combined processing methods that integrate pyrometallurgy and hydrometallurgy for large-scale recycling of LIB waste; 4) Developing lithium recovery technologies from the slag produced during pyrometallurgy treatment; 5) Establishing an LCI Database and scenarios for the life cycle assessment of battery waste recycling processes; 6) Implementing an energy-efficient, zero-discharge system for sulfate-rich wastewater from acidic leaching solutions. Currently, only cathode materials are recycled from LIB waste. However, as the volume of electric vehicle waste batteries tends to increase in the future, recycling of anode materials should also be actively pursued to increase LIBs waste circularity.

Key Words

Waste lithium-ion battery, Recycling technology, Hydrometallurgy, Pyrometallurgy, High-concentration sulfate wastewater

유태열 Tae-youl Ryu , 이선주 Sun-ju Lee , 이승택 Seungtaek Lee , 서민예 Min-ye Seo , 이재영 Jai-young Lee

DOI:10.9786/kswm.2025.42.1.16

Abstract

Hydrochar has been regarded as a promising alternative for recycling and upcycling various wastes streams. In this study, hydrochar from food waste digestate sludge (FWS) was prepared using hydrothermal carbonization (HTC). The properties of the prepared hydrochar were assessed under different conditions, including reaction temperature (180, 220, and 260°C) and time (0.5, 1, and 2 hours). The characterization included analyses of pH, electrical conductivity, proximate composition, elemental composition, calorific value, energy density, and energy yield. A correlation analysis was performed to understand the relationship between these properties and hydrochar’s production operating conditions. The parameters showed stronger relationships with reaction temperature, with several exhibiting high correlation coefficients. In particular, hydrochar’s mass yield, and its carbon, sulfur, and oxygen contents, as well as its calorific value, exhibited strong correlations. The fundamental characterization of hydrochar in this study is expected to serve as valuable data for the efficient recycling of FWS in the future.

Key Words

Food waste digestate sludge, Anaerobic digestion, Hydrothermal carbonization, Hydrochar

김은솔 Eun-sol Kim , 전윤주 Yun-ju Jeon , 김태훈 Tae-hoon Kim , 서시영 Siyoung Seo , 윤여명 Yeo-myeong Yun

DOI:10.9786/kswm.2025.42.1.26

Abstract

Odors from swine manure, primarily ammonia (NH₃) and hydrogen sulfide (H₂S), are significant environmental and public health concerns. This study evaluated the effects of individual and combined odor inhibitors, including phenyl phosphorodiamidate (PPDA), thymol, and FeCl₃, on mitigating ammonia and hydrogen sulfide emissions from swine manure during a 5-day storage period. PPDA inhibits urease activity, reducing urea hydrolysis; its use alone reduced ammonia emissions to 79.1%. Thymol and FeCl₃ presented limited effect on ammonia reduction when applied individually. However, the combination of PPDA and thymol decreased hydrogen sulfide formation to 80.6% due to synergistic interactions that suppressed sulfate-reducing bacteria. Moreover, the addition of FeCl₃ increased hydrogen sulfide removal efficiency to 88.4%, although its impact on ammonia reduction was minimal. This study demonstrated that combining odor inhibitors is a promising strategy for simultaneously mitigating ammonia and hydrogen sulfide emissions from swine manure. Future research could focus on optimizing their application rates to maximize cost-effectiveness and overall efficiency.

Key Words

Ammonia, Hydrogen sulfide, Odor mitigating agents, Swine manure, Urease inhibitor

Jinjuta Owkusumsirisakul , Kyungdu Park , Eunho Jang , Sergio Capareda , Hyungseok Nam

DOI:10.9786/kswm.2025.42.1.34

Abstract

The depletion of fossil fuels and growing environmental concerns highlight the need for renewable energy sources and efficient waste management. This study explores the production of activated carbon from Jatropha de-oiled cake through atmospheric pyrolysis and chemical activation, where the atmospheric pyrolysis of the de-oiled cake generates biochar, which serves as the precursor for activated carbon. The activation process using potassium hydroxide (KOH) was optimized with response surface methodology (RSM) to evaluate the effects of impregnation ratio, activation temperature, and activation time. Under optimal conditions, the process achieved a maximum activated carbon yield of 69.8% and a surface area of 285 m²/g. The activated carbon exhibited high adsorption efficiency, removing 90.3% of acetaminophen from aqueous solutions. These findings demonstrate the potential of Jatropha de-oiled cake for high-value material synthesis, contributing to renewable energy development and sustainable waste management.

Key Words

Activated carbon, Pyrolysis, Jatropha, Response surface methodology (RSM)

권택관 Taek-kwan Kwon , 황용우 Yong-woo Hwang , 정인홍 In-hong Jung

DOI:10.9786/kswm.2025.42.1.48

Abstract

Platinum group metals (PGM) are important and rare metals which are entirely imported from overseas and are only present in a few regions of certain countries. Any supply or demand disruption could pose a significant risk to the domestic advanced industrial sector. Currently, PGM oxide electrodes are not recycled and are entirely exported as scrap. This study focused on developing a novel stripping method for the catalyst layer of PGM oxide electrodes. Mechanical stripping methods used in the industry, such as sandblasting and chemical stripping, are unable to reuse substrates due to potentially damaging the titanium and introducing excessive impurities into the material, which leads to technical limitations in refining and purifying recycled electrodes. Therefore, an experimental study was conducted on a thermochemical stripping method to overcome these shortcomings. By selecting an alkaline surface coating solution and determining the optimal process parameters, such as heat treatment temperature and time, this study presents a novel stripping method that enables the reuse of titanium substrates while minimizing damage and impurities mixed in the stripped material. Later, this approach was used to efficiently recycle iridium, a poorly soluble element among PGM oxide electrodes.

Key Words

Platinum group metal, Electrode, Stripping rate, Thermochemistry, Titanium