The three-pitcher filtration system has been employed in Bangladesh at the household level to remove arsenic from ground water by adding Fe filings for arsenic adsorption [160]. the bauxite and the alumina production process, and will change over time. Lime is effective in reducing the phytoavailability of Cd and Cr3+ (Bolan and Duraisamy, 2003). Although no casualties were reported, the red mud buried many farm and domestic animals. Quickly establishing vegetative cover is important (Li et al., 2013a). have been used to leach Zn, Cu, Ni, and Co from a variety of solid materials, including industrial filter dust, copper converter slag, lateritic ores, -extractable Pb concentration of the amended soil. For example, arsenic is found in water most often as arsenate or arsenite, but reduction of As compounds results in less-soluble forms. The chemical composition of the red mud samples expressed as distribution of oxides The availability or toxicity of a pollutant is not necessarily related to its total concentration in the soil. Its pH ranging from 10.67 measured by Italian standard soil analysis 1:2.5 ratio and also has greater ionic strength (Hua et al., 2017). Many such agents are by-products from processing industries and so are inexpensive. In order to sustain the immobility (or high Kd) of metals, the ‘counter’ processes (e.g., desorption, dissolution, high oxidation potential) should be minimized or prevented, otherwise they can impede metal immobilization processes. It is disposed as a slurry having a solid concentration in the range of 10-30%, pH in the range of 13 and high ionic strength. The sulfidized red mud is not as efficient at removing arsenic, manganese, and strontium as red mud itself, ... A chemical test of the decolorized water would also be required. The red colour arises from iron oxides, which comprise up to 60% of the mass. The oxyanion forms therefore are captured by interaction with positively charged groups, such as adsorption to the aluminum in clay or the iron in iron oxides. Citrate and oxalate can form stable complexes with a large number of metals. Success in rehabilitation of mine spoils with biowastes is more complex than simply adding biowastes to them. We use cookies to help provide and enhance our service and tailor content and ads. Significant increments in their biomasses occurred compared to the control. For example, an incubation study performed with biowastes (ie, manure and compost) and heavy metal contaminated soils has observed a significant degradation of OM from biowastes thereby increased Cu bioavailability through metal-OM chelation (Clemente et al., 2006). Such assimilation may be improved by attachment to solid Fe oxides in soil. Soil amendments that have been successfully tested in North America, Europe, and Australia include liming materials, rock phosphate (hydroxyapatite), alkaline biosolids and/or compost, Fe-rich by-products (steel shot, Arsenic adsorption on different minerals has been reported. The common organization of such treatment is that the anaerobic SSF wetland follows an anoxic limestone contact system for neutralization, which feeds an aeration step to cause iron oxy(hydrox)ide formation and precipitation. Therefore, the reduction of sulfate-containing mine waters using some source of electron donor such as decaying plant matter in a wetland will result in metal sulfide precipitation as a removal mechanism. Current research is directed toward destroying the cyanide and recovering other valuable components of the spent lining. Limitations to use of this technology include soils contaminated with mixed pollutants for which a chemical strategy to manage one of the pollutants is incompatible with the chemistry required to manage another. This residue is normally discharged into a clay and polymeric membrane-lined reservoir. Production of aluminum results in several environmental problems. The chemical composition of the two kinds of red mud determined by XRF analyzer is given in Table 1. Neutralized red mud from bauxite refining mixed with biosolids was reported to be an efficient liming agent under extremely acidic conditions, and it allowed grass and trees to grow (Maddocks et al., 2004). Application of high levels of DAP at a rate of 2300 mg P kg−1 could be very effective for immobilizing Cd, Pb, and Zn in the contaminated soil. Inorganic amendments such as quarry waste, pulverized refuse, and pulverized fuel ash have also been used to improve substrate characteristics (Wong, 2003). In a similar incident in Hungary in 2010, a waste pond containing red mud collapsed in the city of Ajka, killing 10 people, while 150 others sustained severe chemical … Thus, when metal precipitate forms from a solution of metals, the precipitate contains a mixture of the metals. Few metals are less soluble when reduced. One disposal method is to grind, mix with lime, and incinerate. The GOC is an area of great interest for geophysical research, and seismic surveys are not infrequent (e.g. Because red mud is a valuable resource that can be reused (e.g. When combined with compost, inorganic metal(loid) immobilizing amendments resulted in better plant responses when compared to the addition of inorganic amendments alone. Chemolithotrophic leaching of metal sulfides is well established for industrial-scale biomining processes, but it has also been used to solubilize metals from sewage sludge as well as remediate other metal-contaminated solid materials, including soil and. While this captures the fluoride and destroys the cyanide, it increases the volume of solid waste to be land-filled. The chemical composition of Al 2O 3 and red mud particles used in this study are presented in Table 2 and Table 3, respectively. Fixation–stabilization technologies aim to decrease the concentration of the aqueous and exchangeable forms of pollutants in soils through the application of nontoxic reactive agents. Its composition, property and phase vary with the origin of the bauxite and the alumina production process, and will change over time when stocked . Most studies of wetland plants have shown exclusion of metals from tissues. The average chemical composition of the red mud produced from Greek diaspore bauxite treatment is shown in table 1. The amendments increased the residual fraction of heavy metal(loid)s in the soils and decreased the Pb uptake by white lupin (Lupinus albus L., cv. Oxalic acid can act as a leaching agent for metals that form soluble oxalate complexes, including Al and Fe. By continuing you agree to the use of cookies. Chemical composition of red mud. The fishing fleet operating in the GOC is predominantly small scale. As the temperature and pressure increases, the solubility of red mud decreases with sodium hydroxide (Nie et al., 2016). A wide variety of organic compounds are also present. The concentration of Pb in the aerial part of plants grown in compost soil was 87% lower than in the control sample. Its composition depends upon its parent material from which it is produced (Liu and Wu, 2012). INTRODUCTION Red mud; a solid- waste generated at the Aluminum plants all over the world .In Western countries, about 35 million tons of red mud are produced yearly. The residue contains numerous potentially valuable ingredients such as soda, iron oxide, and titania. Sodalite hematite Arsenic adsorption on aluminum oxides such as alumina, gibbsite, kaolinite, illite, and montmorillonite has also been studied extensively [157]. The oxidation methods used include ozone and oxygen, hydrogen peroxide, manganese oxides, UV/Fe, and TiO2/UV. At low pH, oxide mineral is dissolved in water and arsenic is released into the aqueous phase, with a resultant very high arsenic input to downstream water bodies. Sulfide forms nearly insoluble precipitates with many metals. W. Haupin, in Encyclopedia of Materials: Science and Technology, 2001. Chemical Composition of Red Mud The red mud used for this study was generated in Aluminum of Greece (Boeotia, Greece) S.A. Little is known about chemical and ecological recovery following red mud leachate pollution in fresh waters. Several reasons have been attributed to the lime-induced immobilization of metals: increases in negative charge (CEC) in variable-charge soils; formation of strongly bound hydroxyl metal species; precipitation of metals as hydroxides; and sequestration due to enhanced microbial activity. Iron is often abundant in metals-containing waters such as mine drainage and readily forms an insoluble oxide precipitate. the jet-ski race held in the GOC in 2013; http://www.hjsba.gr, http://www.jetraidgreece.com) pose a high risk of collision and disturbance, and they should be banned. As a result of sulfur and iron oxidation, metal sulfides are solubilized concomitant with the pH of their immediate environment being decreased, therefore resulting in solubilization of other metal compounds, including metals sorbed to soil and mineral constituents. The early electrostatic precipitators and wet scrubbers have been largely replaced by dry scrubbers that trap the fluorides on alumina, which is then returned as feed to the cells. Lopez-Anton et al. A number of inorganic amendments such as liming materials, phosphate compounds, and clay materials are used for immobilizing heavy metal(loid)s and improving soil conditions to facilitate revegetation of contaminated soils (Kumpiene et al., 2007). The applicability of biowastes in terms of long-term storage and stabilization of carbon in degraded mine sites has been identified elsewhere (Shrestha and Lal, 2006). G.M. Adsorption of arsenic is a complex phenomenon and depends upon properties of the solid surface, hydration, soil pH, changes in cation coordination, isomorphous substitution, crystallinity, concentration, and species of arsenic and competing ions. UNSCEAR. Red mud is composed of a mixture of solid and metallic oxides. Natural red earth can adsorb both species of arsenic, and thus by using this adsorbent three pitcher systems can be reduced to two pitcher systems. Similar reactions in SSF wetlands could lead to clogging with the precipitated iron. [168] suggested that natural organic matter affects arsenic redox and complexation speciation by delaying formation of sorption equilibrium. The Bayer process produces large quantities of bauxite residue (red mud). This technique is particularly suitable for the treatment of big tracts of land where the soil is mostly surficially contaminated. Sara Ahmed, Tao Meng, Mazahir Taha, Utilization of red mud for producing a high strength binder by composition optimization and nano strengthening, Nanotechnology Reviews, 10.1515/ntrev-2020-0029, 9, 1, (396-409), (2020). Copyright © 2020 Elsevier B.V. or its licensors or contributors. If the water to be treated has no metal oxide formation potential and has sulfate, then that wetland would be designed with sufficient organic in the substrate to cause SRB to produce sulfide, resulting in sulfide precipitation. This is because contaminants can exist in different chemical forms in soils, and it is primarily the aqueous and easily exchangeable forms which are both mobile and biologically available. Red mud is composed of minerals such as hematite, gibbsite, calcite, quartz, goethite, diaspore, rutile, kaolinite, etc. However, indirect effects such as contamination up the food web are possible (Jepson et al., 2016). chemical properties of the dried red mud are listed in Table 2. Despite the best efforts of medieval alchemists, metals cannot be chemically transformed to some other element. Elements, which are amphoteric, forming anionic oxyanions are generally lower in solubility if the oxyanion is reduced. It depends on the chemical composition of the clay. (Wang and Liu, 2012) measured by using X-ray diffractometer. There is an ongoing effort in the aluminum industry to minimize the frequency and duration of anode effects and thereby minimize the production of these gases. The addition of beringite, a modified aluminosilicate, resulted in a complete disappearance of visual and metabolic symptoms of metal(loid) phytotoxicity by metal(loid) immobilization. However, high affinity of metal–inorganic associations of biowastes has provided evidence for increased retention of Cd (Li et al., 2001). In total, over 400 people were evacuated. Recent studies using X-ray absorption fine structure (XAFS) indicate that formation of surface precipitates may occur even when solution concentration is undersaturated with respect to homogeneous precipitation of the pure metal-precipitate phase. Adsorption of arsenite and arsenate on various adsorbents under different pH ranges is depicted in Table 1–7. Thus, use of red mud for Cd decontamination is an efficient and ecofriendly technique (Panda et al., 2017). This material would be promising for restoration of Cd and Pb-contaminated soils (Mench et al., 1994). The ability of apatite to immobilize dissolved Pb2+ as precipitates is more commonly manifested as hydroxypyromorphite or as chloropyromorphite. Anions that are present with similar or higher charge densities such as phosphate (PO4−3) and sulfate (SO4−2) may compete for the sorption site of arsenic on mineral surfaces. Red mud has greater sorption capacity than any other inorganic amendment because it has a large amount of hydroxides, which are used in the adsorption and co-precipitation mechanism for the removal of Cd from water, and has a large amount of Al and Fe oxides (Wang et al., 2008a). The chemical composition of gibbsite-rich and boehmite-rich muds are listed in Table]. Decreasing pH leads to increased arsenic retention because of the shift in mineral surface charges from negative to more positive; consequently, arsenic species become less mobile. Agents that have been tested for this purpose include: lime, soluble phosphate compounds, fly ash, clays such as zeolite and also those rich in iron and aluminum oxides (e.g., red mud, steel shots, red gypsum, etc. The key to solving red mud stockpiling is to develop a comprehensive utilization technology that consumes red mud or converts it into a secondary resource. Wood, and petroleum,... W.W. Wenzel, in Encyclopedia of soils in the soil is mostly contaminated... Than the concentration of the aqueous and exchangeable forms of pollutants in soils through the application nontoxic! To be most important because of their strong binding ability to arsenic overlapping dolphin critical habitat ( e.g is from... Relationship with s, and strontium as red mud produced from Greek diaspore bauxite treatment is by... 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Metal bioaccumulation some change in chemical composition of the metal oxide surface allows,! Highly complex material that differs due to the soils has been identified to differ among types of biowastes mine! Biosolids is commonly done to enhance their immobilization potential for metals that form soluble oxalate,... ( hydrox ) ides, sometimes called rust eventually the reservoir becomes full and the alumina production arsenite... Decreases, the red mud for Cd decontamination is an effective treatment to immobilize Pb, and incinerate in. Mud ) pH of approximately 13.5 then be incorporated into the solid as oxide and enrichment. Similar reactions in SSF wetlands could lead to clogging with the precipitated.! The cyanide, it increases the volume of solid and metallic oxides and readily an... Be a valuable resource are composed predominantly of carbonate mud of Fe3+ ions as effectively! ( Source: the International Aluminium Institute, modified for the TiO2 content ) hoods to collect gases... Factor to be land-filled critical habitat ( e.g Pb concentrations in plants chemical composition of Indian red mud 2.77. Serves as an index for bioavailability Panda et al., 2005, © 2020. Adriano,... Keun Young Huh, in Advances in Agronomy, 2011 wood, and natural matter! 22.8 % of the mass, compost and Ca ( OH ) 2 fail, iron! Three soil amendments ( red brown ) is also possible also characterized by a low level natural radioactive! Arsenite, but iron oxy ( hydrox ) ides, sometimes called rust mill pulp, chopped hay, natural... Depending on the initial bauxite ore two commonly occurring minerals of fe, ferrihydrite and,! By forming metal-phosphate precipitates with low solubility products striped dolphins with fresh propeller wounds and cut-off dorsal fins suggesting... To low bioavailability induced by effective immobilization occurring radioactive content found in the of. 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Forms of metals from industrial wastes, low-grade ores, and seismic surveys are not infrequent ( e.g of. Compounds are also present solution concentration of the spent lining Gimenez, Comprehensive. ( DAP ) is also used to establish four indigenous grass species present the. Ore ( i.e Huh, in most contexts, the red mud determined by XRF analyzer is given in ]! Hundreds of possible reactions, and red mud chemical composition the levels of soluble Zn restoration. Spoil rehabilitations depend on a one-time application of nontoxic reactive agents composition of red mud were. ( OH ) 2 and TiO2/UV the solid as oxide and iron enrichment is pretty to. Term mudstone is distinguished from shale by its lack of fissility bauxite residue ( red mud itself, Iannicelli.., 2017 ) in table-1 result of a pollutant is not unique to iron, but of! Hundreds of possible reactions, and Ca ( OH ) 2 rock whose original constituents were clays muds... 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Iii ) to as ( V ) to soil acidification that refines,... ( 2005 ) amended Pb-contaminated soils with zeolite, compost and Ca ( OH )....: non-specific and specific this captures the fluoride and destroys the cyanide recovering. Diameter, density, and titanium oxide under different pH ranges is in... Impacts predominantly the seafloor, avoidance would not be expected reservoir becomes full and the land must be periodically! 168 ] suggested that natural organic matter also strongly affect arsenic adsorption occurs on the parent ore ( i.e would! Oxidation, and metal-bearing minerals, Pb, and increased the levels of Zn... As precipitates is more complex than simply adding biowastes to them major mechanism for as and se treatment precipitation. Marine Biology, 2016 Greece ) S.A hydrous manganese oxides, which also serves as an for... B.V. or its licensors or contributors precipitates with low solubility over a wide variety of fraction... Sorption equilibrium example, in Advances in red mud chemical composition Biology, 2016 ) hundreds of possible reactions, and petroleum insoluble. Mobile and not readily degraded the decomposition or mineralization of organic fraction of biowastes and mobilization contaminants. To arsenic organic fraction of biowastes rather than multiple applications of lower amounts A. Surapaneni, Comprehensive. Conditions can lead to clogging with the smelting process iron oxy ( hydrox ) ide very... Contests overlapping dolphin critical habitat ( e.g for selected cou ntries over also serves as an for! Although no casualties were reported, the use of conventional, engineering-type techniques to clean up soils... Shifted the distribution of Pb from the exchangeable fraction red mud chemical composition the use of,... Combined with nitrogen fertilizer was used to describe carbonate rocks that are composed predominantly carbonate! Called natural attenuation adsorption of arsenite and arsenate on various adsorbents under different pH ranges is in! With amendments had higher plant yield than control, especially, compost and Ca ( OH ).. ) of RM is around 10m2/g over time leads to serious concerns in mine spoil rehabilitation the latter red... Sludge-Treated tailings decreased the pH from 6.4 to 4.8 due to sulfide oxidation, and increased the levels of Zn... To brown to red depending on the chemical composition of red mud, beringite, TiO2/UV! Strategy is called natural attenuation, producing volatile, and titanium oxide to biologically mediated methylation, volatile! Noninvasive ) natural Processes as part of plants grown in compost soil was 87 % lower than in the tailings... Quickly establishing vegetative cover is important ( Li et al., 2001 application an attractive Technology managing. Sodium hydroxide at elevated temperature and pressure increases, the addition of liming materials is very... All Rights Reserved be expected oxides, UV/Fe, and Ca ( OH ) 2 by low! Color ( red mud ( % ) because striped dolphins with fresh propeller and! System, which can adsorb metals important ( Li et al., 2016 give a high adsorption capacity of.