Environmental Management
F. Abdul; R.F. Rahman; K.A. Purwanto; F.I. Ma'ruf; Y. Setiyorini; V.A. Setyowati; S. Pintowantoro
Abstract
BACKGROUND AND OBJECTIVE: The nickel processing industry has always been related with the issue of carbón dioxide emission. The production of carbon dioxide occurs at different phases of nickel processing, from pretreatment to smelting and refining. In addition to offgas, the nickel processing ...
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BACKGROUND AND OBJECTIVE: The nickel processing industry has always been related with the issue of carbón dioxide emission. The production of carbon dioxide occurs at different phases of nickel processing, from pretreatment to smelting and refining. In addition to offgas, the nickel processing sector also produces solid waste known as slag, which is a byproduct of both smelting and refining processes. One of the slags in the nickel industry is known to contain iron, which is dominant compared to other elements. The primary objective of this study is to investigate the process of carbon dioxide capture by utilizing iron-rich slag derived from the nickel processing industry. The aim is to assess the feasibility of applying iron-rich slag from nickel smelters in the solid carbonation gas process for carbon dioxide capture, focusing on chemical reactions and overall kinetics.METHODS: The iron-rich slag analyzed in this study contains a significant amount of iron oxide. It is theoretically anticipated that the iron oxide content in iron-rich slag could potentially sequester carbon dioxide. The study commenced by preparing the materials, undergoing the carbonation process, and then conducting various characterizations including X-ray diffractometer analysis and thermal gravimetric analysis. Additionally, calculations were performed to determine the percentage of carbon dioxide in the sample and the efficiency of carbonation. The kinetics analysis was also carried out using several models, such as mass transport, chemical reaction, and diffusion-controlled model to estimate the carbón dioxide capture mechanism that occurs.FINDING: The carbon dioxide capture capacity of the iron-rich slag from the ferronickel industry is somewhat limited, albeit still relatively modest. Iron-rich slag was effectively utilized to capture carbon dioxide after thorough analysis. After undergoing a carbonation process for a duration of 4 hours, the percentage of carbon dioxide in the slag witnessed a significant increase, rising from an initial value of 0.28 percent to 1.12 percent. The capture of carbón dioxide gas is due to the reaction between silicate with carbón dioxide gas and water vapor to form siderite. The iron-rich slag operates under the diffusion-controlled model when it comes to capturing carbon dioxide.CONCLUSION: Iron-rich slag is reported to capture carbón dioxide at 175 degrees celsius with carbón dioxide and water vapor condition, which is proven both from thermodynamic calculations and experiments. Iron(II) carbonate is a carbonate compound generated by the carbón dioxide capture reaction by iron-rich slag. However, the stability of iron(II) carbonate in carbón dioxide and water vapor atmosphere is something that needs to be considered in future research. Further investigation can be conducted in the future to explore the potential of utilizing iron-rich slag for capturing carbon dioxide gas, building upon the findings of this preliminary study.
Environmental Science
A.D. Malik; M.C.W. Arief; S. Withaningsih; P. Parikesit
Abstract
BACKGROUND AND OBJECTIVES: Land use and land cover changes are affected by massive construction, urban expansion, and exploitative agricultural management. These pressures threaten the potential of aboveground carbon storage in Rancakalong District, West Java, Indonesia. In that massive construction ...
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BACKGROUND AND OBJECTIVES: Land use and land cover changes are affected by massive construction, urban expansion, and exploitative agricultural management. These pressures threaten the potential of aboveground carbon storage in Rancakalong District, West Java, Indonesia. In that massive construction and agricultural expansion are ongoing, it is critical to detect the potential changes in carbon stocks in the region. This study evaluated the impact of land use and land cover changes on aboveground carbon stock potential in Rancakalong District, West Java, Indonesia, by incorporating several ground-based carbon inventories into geographic information systems and remote sensing approaches. The spatiotemporal dynamics of the aboveground carbon stocks were assessed using Integrated Valuation of Ecosystem Services and Tradeoffs models.METHODS: Aboveground carbon stocks were estimated using the integrated approach of field inventory and geographic information systems. Land use and land cover changes were assessed from remotely sensed imagery data recorded in 2009 and 2021 using the maximum likelihood classification method in the geographic information as a collection of layers and other elements in a map 10.6 package. Tree height and diameter were collected within the purposively distributed plots with a size of 30 × 30 square meters. Vegetation biomass was assessed using an allometric equation, and aboveground carbon stock data were extrapolated to the landscape scale using a linear regression model of measured carbon stocks and the Normalized Difference Vegetation Index derived from recent satellite imagery.FINDINGS: Vegetated areas were predominant in 2009 and 2021. Vegetation covered 51 percent of the total area in 2009, increasing to 57 percent in 2021. Regarding agricultural area, mixed gardens and drylands decreased between 2009 and 2021. Meanwhile, paddy fields were the only agricultural land use to increase between 2009 and 2021. The bare land and built-up expansion related to the observed land clearing for the Cisumdawu Highway mainly came from the conversion of mixed gardens, paddy fields, and drylands. The results show that the land use and land cover changes in Rancakalong District have caused a reduction in aboveground carbon stocks by 11,096 tons between 2009 and 2021. The highest reduction in aboveground carbon stocks occurred in mixed gardens, while a slight increase in aboveground carbon stocks occurred in forests, shrubs, and paddy fields. The results highlight the contribution of mixed gardens to carbon storage as they are visually similar to forests in the structure and composition of vegetation.CONCLUSION: Land use and land cover changes directly affected the aboveground carbon stock potential in Rancakalong District, indicated by an 11,096-ton reduction in the stocks. This shortage of carbon stock potential was mainly attributed to the massive reduction in mixed garden areas between 2009 and 2021 by 12 percent, which caused a significant decrease in aboveground carbon stocks. The application of the Integrated Valuation of Ecosystem Services and Tradeoffs model is efficient in analyzing the effect of land use and land cover change on aboveground carbon stock dynamics and can be widely used in environmental engineering studies involving remote sensing approaches.
