This page has only limited features, please log in for full access.
Rare earths is an intrinsic requisite for clean-efficient technologies. The unsecured supplying source and the necessity making rare earth elements are critical. Accordingly, numerous hunts commence toward exploration of minable ore deposits, unconventional sources, and substitutions. However, conventional rare earths production seems to be unrealistic due to various economic and environmental obstructions, whereas, the unconventional sources have proposed potential alterations for rare earths. Coal fly ash are universally perceived to be the most viable source of rare earths recovery within all kinds of possibly alternative sources. This chapter intentionally studies the properties of coal fly ash with respect to rare earths occurrence. Ongoing techniques regarding rare earths recovery from Circulating Fluidized Bed Combustion coal fly ash and the incorporation of carbon mineralization process were reviewed.
Quang Tuan Lai; Thriveni Thenepalli; Ji Whan Ahn. Utilization of Circulating Fluidized Bed Combustion Fly Ash for Simultaneous Recovery of Rare Earth Elements and CO2 Capture. Clean Coal Technologies 2021, 403 -430.
AMA StyleQuang Tuan Lai, Thriveni Thenepalli, Ji Whan Ahn. Utilization of Circulating Fluidized Bed Combustion Fly Ash for Simultaneous Recovery of Rare Earth Elements and CO2 Capture. Clean Coal Technologies. 2021; ():403-430.
Chicago/Turabian StyleQuang Tuan Lai; Thriveni Thenepalli; Ji Whan Ahn. 2021. "Utilization of Circulating Fluidized Bed Combustion Fly Ash for Simultaneous Recovery of Rare Earth Elements and CO2 Capture." Clean Coal Technologies , no. : 403-430.
Water pollution particularly caused by heavy metal ions and anionic contaminants even in trace amount can pose catastrophic impact on all living organisms. As these contaminants are mostly non-biodegradable and can transformed into complexes, adsorption is a most auspicious technique in recent times. Biochar, a sustainable and low-lost product, synthesized from thermochemical conversion of biomass has attracted research attention with its adsorption prospects of wide range contaminants. However, challenging recovery and often deficient adsorptions forced researchers to develop modification techniques to upgrade the physicochemical characteristics of biochar. These modifications can enhance biochar chemical interactions such as electrostatic attraction, surface complexation, ion exchange, and induction of functional groups. This chapter mainly focussed on the effectiveness of different thermochemical conversion techniques, biochar modifications, and an overview of biochar applications for the efficient removal of heavy metal ions and anionic contaminants from wastewater.
Mohd Danish Khan; Ji Whan Ahn. Environmental Benign Biochar Technologies: Strategic Utilization for CO2 Capture and Wastewater Treatment. Clean Coal Technologies 2021, 181 -214.
AMA StyleMohd Danish Khan, Ji Whan Ahn. Environmental Benign Biochar Technologies: Strategic Utilization for CO2 Capture and Wastewater Treatment. Clean Coal Technologies. 2021; ():181-214.
Chicago/Turabian StyleMohd Danish Khan; Ji Whan Ahn. 2021. "Environmental Benign Biochar Technologies: Strategic Utilization for CO2 Capture and Wastewater Treatment." Clean Coal Technologies , no. : 181-214.
Coronavirus disease (COVID-19) has spread around the world like wildfire, impacting health, industry, the global economy, and the environment. This paper focuses on climate change, discussing the global trend in CO2 emissions and how COVID-19 is impacting climate change. Global warming is the greatest environmental challenge our planet has ever faced. According to the International Energy Agency (IEA), CO2 emissions declined by 8% during 2020. Of the wide range of sustainable technologies available for carbon capture, mineralization technology is the first to produce carbonate minerals by directly reacting minerals with low concentration CO2. This long-term technology affords extended capacity for CO2 storage. We consider the extensive guidelines required for climate change during the battle against COVID-19.
Quang Tuan Lai; Lulit Habte; Thenepalli Thriveni; Lee Seongho; Ji Whan Ahn. COVID-19 Impacts on Climate Change—Sustainable Technologies for Carbon Capture Storage and Utilization (CCUS). The Minerals, Metals & Materials Series 2021, 23 -28.
AMA StyleQuang Tuan Lai, Lulit Habte, Thenepalli Thriveni, Lee Seongho, Ji Whan Ahn. COVID-19 Impacts on Climate Change—Sustainable Technologies for Carbon Capture Storage and Utilization (CCUS). The Minerals, Metals & Materials Series. 2021; ():23-28.
Chicago/Turabian StyleQuang Tuan Lai; Lulit Habte; Thenepalli Thriveni; Lee Seongho; Ji Whan Ahn. 2021. "COVID-19 Impacts on Climate Change—Sustainable Technologies for Carbon Capture Storage and Utilization (CCUS)." The Minerals, Metals & Materials Series , no. : 23-28.
Globally, coal is the largest primary source of electricity. As per the global demand for coal production, coal ash has also subsequently increased. The coal by products such as fly ash and bottom ashes are the main sources for rare earth and other metals. The tremendous benefits of recycling these ashes have wide energy applications. In this paper, we reported characteristic studies of critical rare earth such as scandium and yttrium from the circulating fluidized bed combustion fly ashes. The preliminary study investigated the performance of three reagents, HCl, H2SO4, and HNO3 on rare earth leaching from a Korean circulating fluidized bed combustion fly ash. Hydrochloric acid was selected as the proper reagent used for subsequent experiments. The variables including reagent concentration, leaching time, and temperature in the range of 1.5–4 mol/L, 5–120 min, and 25–80 °C were optimized. The leaching efficiency of scandium and yttrium were at 48 and 45% under the optimized conditions.
Quang Tuan Lai; Thenepalli Thriveni; Ji Whan Ahn. Characteristic Studies of Critical Rare Earths Scandium and Yttrium from Circulating Fluidized Bed Coal Fly Ashes. The Minerals, Metals & Materials Series 2021, 13 -21.
AMA StyleQuang Tuan Lai, Thenepalli Thriveni, Ji Whan Ahn. Characteristic Studies of Critical Rare Earths Scandium and Yttrium from Circulating Fluidized Bed Coal Fly Ashes. The Minerals, Metals & Materials Series. 2021; ():13-21.
Chicago/Turabian StyleQuang Tuan Lai; Thenepalli Thriveni; Ji Whan Ahn. 2021. "Characteristic Studies of Critical Rare Earths Scandium and Yttrium from Circulating Fluidized Bed Coal Fly Ashes." The Minerals, Metals & Materials Series , no. : 13-21.
In September 2015, the United Nations included ‘sustainable consumption and production’ as part of its 12th goal of sustainable development. The EU announced its Circular Economic Package in December 2015 to move from the existing linear economic structure to the net environmental system. Recycling of household waste has become more significant as a circular economic policy has been implemented to reflow waste into the economy through recycling worldwide. In this study, Korea’s household waste generation for 20 years from 1998 to 2017 was analyzed through statistical techniques. Waste generation tended to increase in the order of plastics and cans, and papers tended to decrease. The amount of bottle wastes has been on the decline after increasing. A questionnaire survey on recycling priority was conducted on 261 people, including participants in the EARTH-2019 recycling experience hall, using the analytic hierarchy process (AHP) technique. According to the survey, the recycling priorities of six types of household waste are (first) plastic, (second) cans, viny, scrap metals, (third) paper, and (fourth) bottles. Statistical analysis of mid- to long-term household waste generation and AHP-based household waste recycling priority survey results can be used as basic data, such as environmental analysis in Korea’s recycling-related policies and research.
Seok-Ho Jung; Mee-Hye Lee; Seong-Ho Lee; Ji Whan Ahn. A Study on the Trend of Domestic Waste Generation and the Recognition of Recycling Priorities in Korea. Sustainability 2021, 13, 1732 .
AMA StyleSeok-Ho Jung, Mee-Hye Lee, Seong-Ho Lee, Ji Whan Ahn. A Study on the Trend of Domestic Waste Generation and the Recognition of Recycling Priorities in Korea. Sustainability. 2021; 13 (4):1732.
Chicago/Turabian StyleSeok-Ho Jung; Mee-Hye Lee; Seong-Ho Lee; Ji Whan Ahn. 2021. "A Study on the Trend of Domestic Waste Generation and the Recognition of Recycling Priorities in Korea." Sustainability 13, no. 4: 1732.
In 2016, the Korean government selected carbon capture and utilization (CCU) as one of the national strategic projects and presented a detailed roadmap to reduce greenhouse gas emissions and to create new climate industries through early demonstration of CCU technology. The Korean government also established the 2030 Greenhouse Gas Reduction Roadmap in 2016 and included carbon capture, utilization, and storage (CCUS) technology in the new energy industry sector as a CCU technology. The Korean government recognizes the importance of CCUS technology as a mid- to long-term measure to reduce greenhouse gas emissions and implements policies related to technological development. The United States (U.S.), Germany, and China also expect CCUS technology to play a major role in reducing greenhouse gases in the industrial sector in terms of climate and energy policy. This study analyzed the CCU-related policies and technological trends in the U.S., Germany, and China, including major climate and energy plans, driving roadmaps, some government-led projects, and institutional support systems. This work also statistically analyzed 447 CCU and CCUS projects in Korea between 2010 and 2017. It is expected to contribute to responding to climate change, promoting domestic greenhouse gas reduction, and creating future growth engines, as well as to be used as basic data for establishing CCU-related policies in Korea.
Seok-Ho Jung; Seong-Ho Lee; JiHee Min; Mee-Hye Lee; Ji Ahn. Analysis of the State of the Art of International Policies and Projects on CCU for Climate Change Mitigation with a Focus on the Cases in Korea. Sustainability 2020, 13, 19 .
AMA StyleSeok-Ho Jung, Seong-Ho Lee, JiHee Min, Mee-Hye Lee, Ji Ahn. Analysis of the State of the Art of International Policies and Projects on CCU for Climate Change Mitigation with a Focus on the Cases in Korea. Sustainability. 2020; 13 (1):19.
Chicago/Turabian StyleSeok-Ho Jung; Seong-Ho Lee; JiHee Min; Mee-Hye Lee; Ji Ahn. 2020. "Analysis of the State of the Art of International Policies and Projects on CCU for Climate Change Mitigation with a Focus on the Cases in Korea." Sustainability 13, no. 1: 19.
Phosphorus (P) concentration beyond threshold limit can trigger eutrophication in stagnant water bodies nevertheless it is an indispensable macronutrient for aquatic life. Even in low P concentration (≤1 mg L−1), P can be detrimental for ecosystem's health, but this aspect has not been thoroughly investigated. The elimination of low P content is rather expensive or complex. Therefore, a unique and sustainable approach has been proposed in which valorized bivalve seashells can be used for the removal of low P content. Initially, acicular shaped aragonite particles (~21 μm) with an aspect ratio of around 21 have been synthesized through the wet carbonation process and used to treat aqueous solutions containing P in low concentration (P ≤ 1 mg L−1). Response surface methodology based Box-Behnken design has been employed for optimization study which revealed that with aragonite dosage (140 mg), equilibrium pH (~10.15), and temperature (45 °C), a phosphorus removal efficiency of ~97% can be obtained in 10 h. The kinetics and isotherm studies have also been carried out (within the range P ≤ 1 mg L−1) to investigate a probable removal mechanism. Also, aragonite demonstrates higher selectivity (>70%) towards phosphate with coexisting anions such as nitrate, chloride, sulfate, and carbonate. Through experimental data, elemental mapping, and molecular dynamic simulation, it has been observed that the removal mechanism involved a combination of electrostatic adsorption of Ca2+ ions on aragonite surface and chemical interaction between the calcium and phosphate ions. The present work demonstrates a sustainable and propitious potential of seashell derived aragonite for the removal of low P content in aqueous solution along with its unconventional mechanistic approach.
Mohd Danish Khan; Sonam Shakya; Hong Ha Thi Vu; Lulit Habte; Ji Whan Ahn. Low concentrated phosphorus sorption in aqueous medium on aragonite synthesized by carbonation of seashells: Optimization, kinetics, and mechanism study. Journal of Environmental Management 2020, 280, 111652 .
AMA StyleMohd Danish Khan, Sonam Shakya, Hong Ha Thi Vu, Lulit Habte, Ji Whan Ahn. Low concentrated phosphorus sorption in aqueous medium on aragonite synthesized by carbonation of seashells: Optimization, kinetics, and mechanism study. Journal of Environmental Management. 2020; 280 ():111652.
Chicago/Turabian StyleMohd Danish Khan; Sonam Shakya; Hong Ha Thi Vu; Lulit Habte; Ji Whan Ahn. 2020. "Low concentrated phosphorus sorption in aqueous medium on aragonite synthesized by carbonation of seashells: Optimization, kinetics, and mechanism study." Journal of Environmental Management 280, no. : 111652.
Recycling routes and orientations set the tone for the feasibility of lithium-ion batteries (LIBs) recycling. An economically feasible hydrometallurgical route for the recycling of strategic metals from LIBs cathode materials was in great need both in the sense of achieving the sustainable development of clean energy and emissions reductions. Three scenarios with routes emphasis on higher lithium and cobalt recovery and orientations incline towards high overall recovery and profit, respectively, were compared, i.e., scenarios A and B with the same orientation (high overall recovery) in different routes (higher lithium and cobalt recovery, respectively), scenario B and C with same routes (high cobalt recovery) in different orientations (high overall recovery and profit, respectively). With the assistance of thermodynamic simulations and profit calculations, three scenarios were tested for recycling 1Kg of spent cathode materials. The highest leaching and Li2CO3 precipitation ratio were achieved in scenario A, followed by scenario B with the highest cobalt recovery ratio, however, the optimum profit was achieved in scenario C with the lowest costs. A comparison among scenarios A, B, and C indicate that a profit-oriented strategic metals recovery process is more reasonable for LIBs recycling.
Shuai Gu; Liang Zhang; Bitian Fu; Xinpeng Wang; Ji Whan Ahn. Feasible route for the recovery of strategic metals from mixed lithium-ion batteries cathode materials by precipitation and carbonation. Chemical Engineering Journal 2020, 420, 127561 .
AMA StyleShuai Gu, Liang Zhang, Bitian Fu, Xinpeng Wang, Ji Whan Ahn. Feasible route for the recovery of strategic metals from mixed lithium-ion batteries cathode materials by precipitation and carbonation. Chemical Engineering Journal. 2020; 420 ():127561.
Chicago/Turabian StyleShuai Gu; Liang Zhang; Bitian Fu; Xinpeng Wang; Ji Whan Ahn. 2020. "Feasible route for the recovery of strategic metals from mixed lithium-ion batteries cathode materials by precipitation and carbonation." Chemical Engineering Journal 420, no. : 127561.
A novel mechanism that combines adsorption with chemical precipitation is proposed to interpret the removal of phosphorus with fly ash of municipal solid waste incineration. Thermodynamic modeling results demonstrate the vital roles of both Ca2+ and OH- in the chemical precipitation process. The mechanism is dominated by precipitation at low phosphorus concentrations, while under high phosphorus concentrations it is under a mixed control by precipitation and adsorption in the filtered solution of fly ash. By subtracting the thermodynamic modeling value of precipitation at certain equilibrium pH from the total removal rate at the corresponding pH, the contribution of adsorption to the total phosphorus removal is calculated for the first time in the fly ash solution. The removal process of phosphorus with calcium-containing waste materials under ambient atmosphere may involve coupled reactions between Ca(OH)2 dissolution, chemical precipitation of hydroxyapatite, adsorption of phosphorus on the surface, and carbonation. The removal efficiency peaks in the CO2-free atmosphere with 100% phosphate removal and 98.9% carbonate removal.
Shuai Gu; Bitian Fu; Ji-Whan Ahn; Baizeng Fang. Mechanism for phosphorus removal from wastewater with fly ash of municipal solid waste incineration, Seoul, Korea. Journal of Cleaner Production 2020, 280, 124430 .
AMA StyleShuai Gu, Bitian Fu, Ji-Whan Ahn, Baizeng Fang. Mechanism for phosphorus removal from wastewater with fly ash of municipal solid waste incineration, Seoul, Korea. Journal of Cleaner Production. 2020; 280 ():124430.
Chicago/Turabian StyleShuai Gu; Bitian Fu; Ji-Whan Ahn; Baizeng Fang. 2020. "Mechanism for phosphorus removal from wastewater with fly ash of municipal solid waste incineration, Seoul, Korea." Journal of Cleaner Production 280, no. : 124430.
To use calcite mud waste generated from the paper production process, calcite mud was treated by calcination and then applied as a sorbent agent to remove phosphorus from an aqueous solution. The pre-treatment muds were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. The effects of calcite mud with different calcination temperatures on phosphorus removal were investigated. Different sorbent dosages, contact times, and initial phosphorus concentration conditions were also studied to understand the phosphorus removal mechanism. The results show that phosphorus removal efficiency was increased by increasing the calcination temperature of the mud. The phosphorus removal efficiency over 10 min increased by 35%, 82%, 98%, and 100% with 4.5, 6.75, 9.0, and 11.25 mg, respectively, of calcite mud calcined at 1000 °C. However, the efficiency decreased as initial phosphorus concentration increased. To study the phosphorus removal trend, the pseudo-first-order, pseudo-second-order, and intraparticle diffusion kinetic models were used. The Langmuir and Freundlich isotherm models were also used to further investigate the phosphorus adsorption mechanism characteristics of the calcite mud.
Hong Vu; Mohd Khan; Van Tran; Dang Quang; Van-Duong Dao; Seongho Lee; Ji Ahn; Seok-Ho Jung. Use of Calcite Mud from Paper Factories in Phosphorus Treatment. Sustainability 2020, 12, 5982 .
AMA StyleHong Vu, Mohd Khan, Van Tran, Dang Quang, Van-Duong Dao, Seongho Lee, Ji Ahn, Seok-Ho Jung. Use of Calcite Mud from Paper Factories in Phosphorus Treatment. Sustainability. 2020; 12 (15):5982.
Chicago/Turabian StyleHong Vu; Mohd Khan; Van Tran; Dang Quang; Van-Duong Dao; Seongho Lee; Ji Ahn; Seok-Ho Jung. 2020. "Use of Calcite Mud from Paper Factories in Phosphorus Treatment." Sustainability 12, no. 15: 5982.
In present work, environmentally benign green aragonite crystals were synthesized from waste chicken eggshells and bivalve seashells through a simple and low-cost wet carbonation method. This method involves a constant stirring of calcium oxide slurry and magnesium chloride suspension in aqueous solution with constraint carbon dioxide injection at 80 °C. The physicochemical properties of the synthesized aragonite were further compared with the aragonite synthesized from commercial calcium oxide. The morphological analysis, such as acicular shape and optimum aspect ratio (~21), were confirmed by scanning electron microscopy. The average crystal size (10–30 µm) and specific surface area (2–18 m2 g−1) were determined by particle size and Brunauer–Emmett–Teller analysis, respectively. Moreover, a schematic crystal growth mechanism was proposed to demonstrate the genesis and progression of aragonite crystal. Green aragonite can bridge the void for numerous applications and holds the potential for the commercial-scale synthesis with eggshells and bivalve seashells as low-cost precursors.
Lulit Habte; Mohd Danish Khan; Natnael Shiferaw; Adeeba Farooq; Mee-Hye Lee; Seok-Ho Jung; Ji Whan Ahn. Synthesis, Characterization and Mechanism Study of Green Aragonite Crystals from Waste Biomaterials as Calcium Supplement. Sustainability 2020, 12, 5062 .
AMA StyleLulit Habte, Mohd Danish Khan, Natnael Shiferaw, Adeeba Farooq, Mee-Hye Lee, Seok-Ho Jung, Ji Whan Ahn. Synthesis, Characterization and Mechanism Study of Green Aragonite Crystals from Waste Biomaterials as Calcium Supplement. Sustainability. 2020; 12 (12):5062.
Chicago/Turabian StyleLulit Habte; Mohd Danish Khan; Natnael Shiferaw; Adeeba Farooq; Mee-Hye Lee; Seok-Ho Jung; Ji Whan Ahn. 2020. "Synthesis, Characterization and Mechanism Study of Green Aragonite Crystals from Waste Biomaterials as Calcium Supplement." Sustainability 12, no. 12: 5062.
In the pulp and paper industry, the white liquor obtained from the causticizing green liquor in the smelting process mostly contains NaOH and Na2S. These chemicals are returned to the digester for reuse in the pulping process. The lime mud (LM) material is obtained from the reaction of the causticization process in paper industries. It is mainly composed of CaCO3; it appears with a green color with a high moisture content; and it has a small proportion of impurities such as non-process elements, for example Fe, Na, Mg, Al, Si, P, and S oxides and other toxic metals. This lime mud has poor whiteness with less efficiency due to its contaminated with impurities. The recycling or reutilizing process for lime mud and solid wastes are minimizing its toxic effect on the environment. The present study proposed to improve the whiteness of the waste lime mud by the calcination and hydration process at high temperatures and reutilizing it for hand sheets, making the process improve the paper brightness. In this study, we used a lime mud sample for calcination at 1000 °C and 1200 °C for 2 h and hydration at different times (3–24 h) with different temperatures (30–80 °C) and measured the powder whiteness and hand sheet brightness. The results indicated that after the calcination and hydration process, the lime mud sample whiteness was improved and that re-utilization with pulp for making hand sheets also can improve the paper brightness. It can be concluded that waste lime mud sample purification and the re-utilization process are more advantageous in paper industries.
Ramakrishna Chilakala; Thriveni Thenepalli; Seongho Lee; Hong Ha Thi Vu; Lai Quang Tuan; Jeongyun Kim; Ji Whan Ahn. Sequential In-Situ Carbonation Process for the Preparation of Hand Sheets with Waste Lime Mud. Reactions 2020, 1, 3 -15.
AMA StyleRamakrishna Chilakala, Thriveni Thenepalli, Seongho Lee, Hong Ha Thi Vu, Lai Quang Tuan, Jeongyun Kim, Ji Whan Ahn. Sequential In-Situ Carbonation Process for the Preparation of Hand Sheets with Waste Lime Mud. Reactions. 2020; 1 (1):3-15.
Chicago/Turabian StyleRamakrishna Chilakala; Thriveni Thenepalli; Seongho Lee; Hong Ha Thi Vu; Lai Quang Tuan; Jeongyun Kim; Ji Whan Ahn. 2020. "Sequential In-Situ Carbonation Process for the Preparation of Hand Sheets with Waste Lime Mud." Reactions 1, no. 1: 3-15.
Accelerated carbonation is an effective and attractive method for the utilization of captured and stored CO2. It has versatile applications in different fields. One of the applications presented in this study was investigation of the efficiency of carbonation of Ca(OH)2 derived from waste eggshell to remove heavy metals from wastewater. Cadmium (Cd(II)) and lead (Pb(II)) were the target heavy metals for this study. Three parameters were studied: Ca(OH)2 dosage, initial Cd(II) and Pb(II) concentration, and CO2 flow rate. The optimum conditions were 3 g/L of Ca(OH)2, 100 mg/L of initial metal concentration and 1 L/min of CO2 flow rate where the removal efficiencies were found to be 99.99% and 99.63% for Cd(II) and Pb(II) respectively. The phase transformation has also been detected by XRD, FTIR and TGA/DTA analysis. All the results showed a transformation of Ca(OH)2 to CaCO3 (calcite) due to complete carbonation. The transfer of CO2 during calcite formation in the presence of Pb(II) and Cd(II) was slightly retarded by a retarding factor of 0.06 and 0.09 respectively. The carbonation process was also applied to real wastewater and the performance was effective although it had very low concentrations of cadmium and lead. Precipitation of metal carbonate was the dominant mechanism for the removal of heavy metals.
Lulit Habte; Natnael Shiferaw; Thenepalli Thriveni; Dure Mulatu; Mee-Hye Lee; Seok-Ho Jung; Ji Whan Ahn. Removal of Cd(II) and Pb(II) from wastewater via carbonation of aqueous Ca(OH)2 derived from eggshell. Process Safety and Environmental Protection 2020, 141, 278 -287.
AMA StyleLulit Habte, Natnael Shiferaw, Thenepalli Thriveni, Dure Mulatu, Mee-Hye Lee, Seok-Ho Jung, Ji Whan Ahn. Removal of Cd(II) and Pb(II) from wastewater via carbonation of aqueous Ca(OH)2 derived from eggshell. Process Safety and Environmental Protection. 2020; 141 ():278-287.
Chicago/Turabian StyleLulit Habte; Natnael Shiferaw; Thenepalli Thriveni; Dure Mulatu; Mee-Hye Lee; Seok-Ho Jung; Ji Whan Ahn. 2020. "Removal of Cd(II) and Pb(II) from wastewater via carbonation of aqueous Ca(OH)2 derived from eggshell." Process Safety and Environmental Protection 141, no. : 278-287.
Based on the concept of recycling waste with waste, the mixed cathode materials of spent lithium-ion batteries were recycled with waste electrolyte from spent lead–acid batteries. With the assistance of thermodynamic simulations, the optimized recycling path of the mixed cathode materials was proposed and tested. A higher overall recycling ratio of valuable metals, that is, 94.9% of lithium, 94.5% of cobalt, 94.4% of nickel, and 95.5% of manganese, was achieved by replacing the oxalates/carbonates used in the precipitation process with sulfides and reducing the solubility of lithium carbonate in the lithium precipitation step at room temperature with ethanol. A higher ethanol-to-water ratio yielded a higher precipitation ratio of lithium until the ratio reached 5:1. High-purity lithium carbonate and cobalt (99.9%) were recovered as nanoparticles and nanoribbons, respectively, through precipitation using carbon dioxide in a solution with a 4:1 ethanol-to-water ratio and electrodeposition at E = −0.4 V in a traditional three-electrode system. Furthermore, the poisonous heavy metal (lead) was separated and stabilized as lead sulfide.
Shuai Gu; Liang Zhang; Bitian Fu; Ji Whan Ahn; Xinpeng Wang. Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations. Journal of Cleaner Production 2020, 266, 121827 .
AMA StyleShuai Gu, Liang Zhang, Bitian Fu, Ji Whan Ahn, Xinpeng Wang. Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations. Journal of Cleaner Production. 2020; 266 ():121827.
Chicago/Turabian StyleShuai Gu; Liang Zhang; Bitian Fu; Ji Whan Ahn; Xinpeng Wang. 2020. "Recycling of mixed lithium-ion battery cathode materials with spent lead-acid battery electrolyte with the assistance of thermodynamic simulations." Journal of Cleaner Production 266, no. : 121827.
Spent electrolyte from lead-acid battery contains high concentrations of sulfate acid and heavy metals; therefore without proper handling, they might cause severe environmental pollution. A relatively high concentration of sulfate ions (approximately 3000 mg/L) and heavy metals still exists in the effluent even after precipitation with slaked lime and carbonation process, which need to be further processed to lower both the concentrations of sulfate and heavy metals for direct discharge. A process that involves the reduction of sulfate to sulfide with sulfate-reducing bacteria and precipitation of the excessive sulfide with Fe(OH)2 was adopted to dispose of the effluent after precipitation and carbonation for direct discharge. Thermodynamic calculations were adopted to narrow down the optimum experimental range and understand the precipitation mechanism. In the whole process, no new impurities nor ions were introduced and 99.2% of sulfate, 99.9% of sulfide, 99.1% of Ca and more than 94.6% of Pb and 99.8% of Cd were removed and the obtained effluent was safe to discharge.
Shuai Gu; Bitian Fu; Ji Whan Ahn. Simultaneous Removal of Residual Sulfate and Heavy Metals from Spent Electrolyte of Lead-Acid Battery after Precipitation and Carbonation. Sustainability 2020, 12, 1263 .
AMA StyleShuai Gu, Bitian Fu, Ji Whan Ahn. Simultaneous Removal of Residual Sulfate and Heavy Metals from Spent Electrolyte of Lead-Acid Battery after Precipitation and Carbonation. Sustainability. 2020; 12 (3):1263.
Chicago/Turabian StyleShuai Gu; Bitian Fu; Ji Whan Ahn. 2020. "Simultaneous Removal of Residual Sulfate and Heavy Metals from Spent Electrolyte of Lead-Acid Battery after Precipitation and Carbonation." Sustainability 12, no. 3: 1263.
In the present work, waste eggshells were used as a precursor for the synthesis of aragonite crystals through the wet carbonation method. Cadmium (Cd2+) and lead (Pb2+) were removed by the synthesized aragonite from synthetic wastewater. The influence of initial solution pH, contact time, Cd2+ and Pb2+ concentration, and sorbent dosage were evaluated. The major sorption was observed in the first 100 mins and 360 mins for Pb2+and Cd2+ respectively reaching sorption equilibrium at 720 mins (12 hr). The sorption capacity toward Pb2+ was much higher than toward Cd2+. Both heavy metals displayed high sorption capacities at initial pH 6. The pseudo-second-order kinetic model fits well with the experimental data with a higher correlation coefficient R2. Two isotherm models were also evaluated for the best fit with the experimental data obtained. Langmuir isotherm best fits the sorption of the metals on aragonite synthesized from eggshells. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) results of sorbent after sorption showed that the mechanism of sorption was dominated by surface precipitation. Therefore, aragonite crystals synthesized from waste eggshells can be a potential substitute source for the removal of Cd2+ and Pb2+ from contaminated water.
Lulit Habte; Natnael Shiferaw; Mohd Danish Khan; Thenepalli Thriveni; Ji Whan Ahn. Sorption of Cd2+ and Pb2+ on Aragonite Synthesized from Eggshell. Sustainability 2020, 12, 1174 .
AMA StyleLulit Habte, Natnael Shiferaw, Mohd Danish Khan, Thenepalli Thriveni, Ji Whan Ahn. Sorption of Cd2+ and Pb2+ on Aragonite Synthesized from Eggshell. Sustainability. 2020; 12 (3):1174.
Chicago/Turabian StyleLulit Habte; Natnael Shiferaw; Mohd Danish Khan; Thenepalli Thriveni; Ji Whan Ahn. 2020. "Sorption of Cd2+ and Pb2+ on Aragonite Synthesized from Eggshell." Sustainability 12, no. 3: 1174.
The rapid economic growth of Vietnam has increased the amount of coal ash waste during electricity generation from coal-fired thermal power plants. This waste is being dumped even though the capacity of dumping sites will not be sufficient in the future. Accordingly, Korean technologies of recycling ashes, modifying them into a valuable product, and fixing carbon dioxide via carbon mineralization, can be an alternative to dumping. In this study, we aimed to investigate the feasibility of deploying carbon mineralization technology to Vietnam while considering technological, legal, and network perspectives. The material properties of coal ash and the applicability of coal ash recycling technology were briefly investigated in Vietnam. Legislation has progressed, focusing on recycling coal ash as a building material, with supportive measures on investment and international cooperation. Meanwhile, a bilateral network between Vietnam and the Republic of Korea at the institutional and governmental levels strengthened the implementation of practical technology cooperation. In conclusion, we considered various perspectives in terms of the technology transfer of recycling coal ash. This technology transfer model can contribute to enhancing the possibility of successful technology cooperation for solving the environmental problems of coal ash.
Jongyeol Lee; Taeyoon Kim; Mina Sung; Hong Ha Thi Vu; Kyung Nam Shin; Ji Whan Ahn. An Integrative Approach to International Technology Transfer for Recycling Vietnam Coal Ash with Consideration of the Technological, Legal, and Network Perspectives. Sustainability 2020, 12, 771 .
AMA StyleJongyeol Lee, Taeyoon Kim, Mina Sung, Hong Ha Thi Vu, Kyung Nam Shin, Ji Whan Ahn. An Integrative Approach to International Technology Transfer for Recycling Vietnam Coal Ash with Consideration of the Technological, Legal, and Network Perspectives. Sustainability. 2020; 12 (3):771.
Chicago/Turabian StyleJongyeol Lee; Taeyoon Kim; Mina Sung; Hong Ha Thi Vu; Kyung Nam Shin; Ji Whan Ahn. 2020. "An Integrative Approach to International Technology Transfer for Recycling Vietnam Coal Ash with Consideration of the Technological, Legal, and Network Perspectives." Sustainability 12, no. 3: 771.
Hinai green tuff, which is found in Akita Prefecture, Japan, is used for the production of building materials, etc. About 60% of all stone is emitted as waste powder and therefore it is important to find ways for recycling it. In this work, the characteristics of green tuff powder have been investigated. The results of scanning electron microscope (SEM) and elemental map observations indicate that the green tuff contains TiO2 on zeolite. The green tuff can therefore be used as a natural catalyst for producing hydrogen peroxide with moisture and oxygen with light. The optimum calcined temperature of the green tuff powder is about 800 °C, producing the hydroxyl radical from hydrogen peroxide decomposition without ultraviolet light (UV) and decomposition of the superoxide anion. As the application of green tuff powder, Cavendish banana trees found in the Philippines infected by a new Panama disease were treated with powder suspension in order to remove the fungus (a type of Fusarium wilt) due to the photocatalyst characteristics of powder. The suspension, prepared by using the powder was sprayed on the infected banana trees for about one month. Photograph observation indicated that the so-called 800 °C suspension spray was more effective in growing the infected banana trees.
Toyohisa Fujita; Josiane Ponou; Gjergj Dodbiba; Ji-Whahn Anh; Siminig Lu; Mohammed F. Hamza; Yuezou Wei. Removal of Banana Tree Fungi Using Green Tuff Rock Powder Waste Containing Zeolite. Catalysts 2019, 9, 1049 .
AMA StyleToyohisa Fujita, Josiane Ponou, Gjergj Dodbiba, Ji-Whahn Anh, Siminig Lu, Mohammed F. Hamza, Yuezou Wei. Removal of Banana Tree Fungi Using Green Tuff Rock Powder Waste Containing Zeolite. Catalysts. 2019; 9 (12):1049.
Chicago/Turabian StyleToyohisa Fujita; Josiane Ponou; Gjergj Dodbiba; Ji-Whahn Anh; Siminig Lu; Mohammed F. Hamza; Yuezou Wei. 2019. "Removal of Banana Tree Fungi Using Green Tuff Rock Powder Waste Containing Zeolite." Catalysts 9, no. 12: 1049.
This paper studies the utilization and management of the waste mollusk shell. The two major export countries of mollusk shell are the Southeast Asia’s Thailand and the Philippines. First, the aquaculture of oysters and bivalve shells has been studied as background understanding. The effect of the global climate change on farming and the consequences of farming on the nearby environment and neighborhoods have also been discussed. The utilization technologies on the waste shell are available on a small scale and not industrialized. This study offers an enabling context under which a suitable method can take action to solve the overflow waste shell problem, and at the same time, provide sustainable management.
Ramakrishna Chilakala; Chottitisupawong Thannaree; Eunsoo Justin Shin; Thriveni Thenepalli; Ji Whan Ahn. Sustainable Solutions for Oyster Shell Waste Recycling in Thailand and the Philippines. Recycling 2019, 4, 35 .
AMA StyleRamakrishna Chilakala, Chottitisupawong Thannaree, Eunsoo Justin Shin, Thriveni Thenepalli, Ji Whan Ahn. Sustainable Solutions for Oyster Shell Waste Recycling in Thailand and the Philippines. Recycling. 2019; 4 (3):35.
Chicago/Turabian StyleRamakrishna Chilakala; Chottitisupawong Thannaree; Eunsoo Justin Shin; Thriveni Thenepalli; Ji Whan Ahn. 2019. "Sustainable Solutions for Oyster Shell Waste Recycling in Thailand and the Philippines." Recycling 4, no. 3: 35.
In this study, both the extended logarithmic mean divisia index (LMDI) model and the system dynamics (SD) model were used to explore determinants of CO2 emission change during 1995–2016 and to predict the emission mitigation potential from 2016 to 2030 in Shanghai (China). Some novel factors (e.g., private car ownership, urban travel structure, and income level) were chosen and added to the LMDI model. The combination of the LMDI and SD models might provide a new pathway for policymakers to cope with such sophisticated issues. The results showed that: (1) GDP per capita is the main positive driving force for CO2 emission growth, followed by population, average income level per capita, and car ownership per capita. Energy intensity is the main factor for carbon mitigation, followed by economic structure, residential energy intensity, and emission coefficient. (2) The additive effect of different scenarios is essential for emission control. (3) CO2 emissions and emission per capita would peak by 2025 at the level of 218.20 Mt and 8.83 t per capita, respectively. Tertiary industry and public travel model promotion, power generation structure, and primary energy structure optimization would facilitate emission mitigation in Shanghai, which could also be a reference for other similar mega-cities in developing countries.
Shuai Gu; Bitian Fu; Thenepalli Thriveni; Toyohisa Fujita; Ji Whan Ahn. Coupled LMDI and system dynamics model for estimating urban CO2 emission mitigation potential in Shanghai, China. Journal of Cleaner Production 2019, 240, 118034 .
AMA StyleShuai Gu, Bitian Fu, Thenepalli Thriveni, Toyohisa Fujita, Ji Whan Ahn. Coupled LMDI and system dynamics model for estimating urban CO2 emission mitigation potential in Shanghai, China. Journal of Cleaner Production. 2019; 240 ():118034.
Chicago/Turabian StyleShuai Gu; Bitian Fu; Thenepalli Thriveni; Toyohisa Fujita; Ji Whan Ahn. 2019. "Coupled LMDI and system dynamics model for estimating urban CO2 emission mitigation potential in Shanghai, China." Journal of Cleaner Production 240, no. : 118034.