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Water contamination by arsenic has been recorded as an important health problem of global concern; even though the adsorption process has shown to be one of the best removal technologies, there are no adsorbents able to reduce its concentration to drinking water standards (0.010. mg/l) when arsenic is present at high initial concentrations (>1. mg....
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... study of adsorption kinetics permits an estimation of the type of adsorption of contaminants occurring on the sur- face of the adsorbent. 65 Table 7 shows the equation and description of the models of adsorption kinetics (pseudo-first order, pseudo-second order, and Elovich) 66-68 ; these models are the most cited in scientific articles or published works related to adsorption models of heavy metals because they are best able to fit the data. 65,69 The equations are given in their linear form. ...
Citations
... Generally, for kinetic modeling, several studies have recommended a minimum of at least 3 measured experimental data points [54][55][56]. All the modeling in this study made use of 6 measured experimental data, which were taken at T = 0, 30, 45, 60, 75, and 90 days. ...
p align="justify">The high prospect of mycoremediation and the lingering issues of Total Petroleum Hydrocarbons (TPHs), associated with crude oil pollution in Ogoniland, Niger Delta, Nigeria, necessitate investigations for sustainable remediation options. Therefore, mycoremediation of different contaminated soils (clayey, sandy, and loamy) and sediments collected within the study area was carried out using Pleurotus ostreatus and fermented palm wine, both optimized with Tween 80, for a period of 90 days. Results revealed variation in soils and sediments TPHs content, in the range of 120 to 525 g/kg dry soil (about 12% to 50% of TPHs contamination), which far exceeded the soil threshold value of 10 g/kg dry soil or 1%. Also, the TPHs concentrations in the soils and sediments, and the remediation efficiency were directly related to the textural properties, with the highest TPHs concentrations in clayey soils and the highest remediation efficiencies in loamy soils. Both mycoremediation agents, enhanced with Tween 80, achieved TPHs remediation above 98% in all the treatments (except in sandy soil). In all cases, the mycoremediation proceeded via pseudo second-order kinetics, and the removal rates peaked at 45–75 days. The kinetic insights also establish the initial TPHs concentration as one of the key factors influencing the remediation efficiency. This study further revealed that mycoremediation of TPHs works best in loamy soils; therefore, shifting soil properties towards those of loamy during mycoremediation is highly recommended. Consequently, with the abundant mycoremediation resources in the Niger Delta, mycoremediation can provide a sustainable option in the clean-up of the petroleum-contaminated soils and sediments.</p
... However, for all the experiments, the PSO has the highest R 2 values; this indicates the applicability of the PSO kinetic model to describe the adsorption process. The PSO model is commonly associated with covalent bonding between the adsorbent and adsorbate (chemisorption) [42]. The determination coefficients for PSO varied from 0.9214 to 0.9863 for the worst and best fit, respectively. ...
Adsorption is a complex process since it is affected by multiple variables related to the physicochemical properties of the adsorbate, the adsorbent and the interface; therefore, to understand the adsorption process in batch systems, kinetics, isotherms empiric models are commonly used. On the other hand, artificial neural networks (ANNs) have proven to be useful in solving a wide variety of complex problems in science and engineering due to their combination of computational efficiency and precision in the results; for this reason, in recent years, ANNs have begun to be used for describing adsorption processes. In this work, we present an ANN model of the adsorption of fluoride ions in water with layered double hydroxides (LDHs) and its comparison with empirical kinetic adsorption models. LHD was synthesized and characterized using X-Ray diffraction, FT-Infrared spectroscopy, BET analyses and zero point of charge. Fluoride ion adsorption was evaluated under different experimental conditions, including contact time, initial pH and initial fluoride ion concentration. A total of 262 experiments were conducted, and the resulting data were used for training and testing the ANN model. The results indicate that the ANN can accurately forecast the adsorption conditions with a determination coefficient R2 of 0.9918.
... At all pH values, arsenate has been reported to be more strongly bound to various soil components than arsenite (Ritter et al., 2006). Steel slag has several mineralogical phases, viz., iron oxides (hematite, goethite, maghemite, and magnetite), magnesium oxide (periclase), and calcium compounds (CaCO 3 ) which show adsorptive properties (Mercado-Borrayo et al., 2014). Upon hydrolysis reaction, the iron oxides in steel slag get converted to oxy-hydroxides and form active surfaces of pHdependent charge in soil. ...
... At alkaline soil pH conditions, there could be two major reactions that facilitate As removal from steel slag-amended soils. The first reaction is the ligand exchange of As(V) leading to the formation of bidentate-binuclear, bidentatemononuclear, or monodentate complexes on the oxy-hydroxide surfaces (Mercado-Borrayo et al., 2014), and the second is the cation bridging on the negatively charged sites of steel slag-soil mixture. In addition, these minerals offer a large surface area and abundant positive charges on their surface even at circumneutral-slightly-alkaline pH to make the chemisorption of oxyanions more convenient (Kosmulski, 2011). ...
The retention and mobility of arsenic (As) in soil depend on various physical and chemical factors. The knowledge of the sorption–desorption chemistry of As in soil is necessary for predicting the fate and behavior of As in soil environments. Therefore, this study assessed different organic (sugarcane bagasse and vermicompost) and inorganic amendments (steel slag and fly ash) for their impact on sorption–desorption of As in texturally different contaminated soils (of sandy clay (SC) and sandy clay loam (SCL) texture) to understand the effect of amendments on As retention and mobility. The results showed that the sorption data fitted well with both Langmuir and Freundlich isotherm equations. The As sorption capacity was significantly enhanced with the application of all amendments. At 30 °C, the adsorption maxima (qmax) of SC soils enhanced to a greater extent following the order: steel slag (278 mg kg⁻¹) > sugarcane bagasse (264 mg kg⁻¹) > vermicompost (246 mg kg⁻¹) > fly ash (242 mg kg⁻¹). Whereas, in SCL, the order of qmax was steel slag (145 mg kg⁻¹) > sugarcane bagasse (132 mg kg⁻¹) > fly ash (120 mg kg⁻¹) > vermicompost (118 mg kg⁻¹). Desorption index (DI) was invariably to > 1 at both temperatures with the application of amendments indicating hysteretic desorption of As. The free energy change (ΔG°) was negative in all treatments and soils (indicating a favorable sorption process) with positive entropy change (ΔS°) values. The study recommends steel slag as the most effective amendment for enhancing As (V) retention in contaminated soils, due to its higher sorption capacity compared to other amendments like sugarcane bagasse, vermicompost, and fly ash. The amendments generally improved As sorption in both soils, reducing As mobility and potentially limiting its environmental spread.
... This may be due to the fact that the sorbent's surface has been saturated and is on the verge of reaching equilibrium. The Lagergren (Pseudo first order) model states that the adsorption rate is determined by the accessible sites in the adsorbent for the physisorption process [57]. ...
Water pollution is one of the major concerns due to rapid industrialization and urbanization. Wastewater treatment has been an area of great interest for the researchers and among many technologies developed for water treatment, adsorption is the most preferred due to its efficiency and ability of been economical method. In this research, eggshell powder (ESP) is converted into modified eggshell powder (MESP) through chemical and thermal treatment (at 550 °C for 2 h) to use it as an adsorbent to remediate Pb2+ and Methylene blue (MB) from water, then it is transferred into modified eggshell powder magnetic composite (MESPMC) with iron coating to resolve the separation challenges and to boost the MESP's adsorption efficiency. FTIR analysis identified the functional groups of ESP, MESP, and MESPMC. XRD analysis reveals a hexagonal crystal structure of calcite in MESP and a combination of the hexagonal crystal structure of calcite and the cubic crystal structure of iron in MESPMC. The Scherrer equation is used to determine the average crystallite sizes of MESP and MESPMC, which are 22.59 nm and 12.15 nm, respectively. The SEM image shows the irregular shape of the MESP and MESPMC particles, as well as the active coating layer in MESPMC. EDX analysis reveals that Ca (20.92 %), O (56.83 %), and Fe (41.03 %), O (48.83 %) are the most abundant elements in MESP and MESPMC respectively. TGA analysis points out that MESPMC outperforms MESP in terms of thermal stability between 600 and 750 °C. MESP and MESPMC were found to be very efficient adsorbent for lead and methylene blue in aqueous medium. At 40 mg/mL adsorbent dosage, ESP, MESP, and MESPMC had the highest yields of Pb2+ removal, with 46.996 %, 99.27 %, and 99.78 % respectively at 200 rpm for 60 min with 25 °C. Furthermore, at the 0.5 mg/mL adsorbent dosage, ESP, MESP, and MESPMC have the maximum removal efficiency of methylene blue, with 47.19 %, 90.1 %, and 92 %, respectively at 200 rpm for 30 min with 25 °C. In both cases, the removal efficiency of MESPMC is slightly higher than that of MESP and much higher than that of ESP. Additionally, the results confirm that MESP and MESPMC are potential environment-friendly bio sources to remediate heavy metal (Pb2+) and methylene blue dye from water.
... A straight line of ln (Qe −Qt) versus t suggests the applicability of this kinetic model, and Qe and K1 can be determined from the intercept and slope of the plot, respectively. Pseudo-second-order by Ho [23] describes the adsorption reaction rate with dependent energetically heterogeneous sites on the adsorbent; it is considered a chemisorption model [64]. The pseudo-second-order equation is expressed as Eq. ...
This study modified current bentonite with zinc oxide (ZnO) and investigated the performance of phenol adsorption. The material bentonite-ZnO was successfully synthesized and characterized with XRD, SEM-EDX, and FT-IR. The adsorption performance was determined by adsorption equilibrium, kinetics, and thermodynamic parameters. The adsorption, kinetic, and thermodynamic parameters were compared alternatively. The phenol adsorption capacity was obtained from Langmuir and Freundlich adsorption isotherm models, which for bentonite-ZnO was fit with both isotherm models (Langmuir R2 = 0.997 and Freundlich R2 = 0.9515) and was favourable than activated bentonite (n value bentonite-ZnO = 2.389; activated bentonite = 0.898). A kinetic model was tested with pseudo-first-order, pseudo-secondorder, and intraparticle diffusion models which bentonite-ZnO and activated bentonite fit in the pseudo-second-order with an excellent agreement (R2 = 0.999). Several thermodynamic parameters such as enthalpy, Gibbs free energy, and bentonite-ZnO have an entropy more than zero (ΔS = 0.008 J/mol.K), which demonstrated the feasibility and spontaneity (ΔG<0) and endothermic nature (ΔH = 3.056 kJ/mol) of the phenol adsorption process. Several thermodynamic parameters such as enthalpy, Gibbs free energy, and bentonite-ZnO have an entropy more than zero (ΔS = 0.008 J/mol.K), which demonstrated the feasibility and spontaneity (ΔG < 0) and endothermic nature (ΔH = 3.056 kJ/mol) of the phenol adsorption process. Based on the result data in this article, modified bentonite with ZnO has increased the ability for phenol adsorption than currently activated bentonite
... Steelmaking slags were tested for phosphorus removal from wastewater [42] and fish farm sludge, [43] for nitrogen removal from the wetlands [44] and heavy metals removal -As, [45] Cd, [46,47] Mn, [48] and Pb. [47] EAF slag presents a potential solution to address the issue of excessive phosphate in the water within the Chicago-Gary region. ...
This article presents a comprehensive review of electric arc furnace (EAF) slag recycling in the United States, examining its classification and the associated challenges and opportunities of its industrial use. The study affirms EAF slag's nonhazardous status. The main challenges identified in EAF slag applications include substantial variations in composition and volume instability during/after hydration. Analysis of the U.S. recycling practices reveals that EAF slag is predominantly reused, with minimal landfill disposal. However, its prevalent use as a low value‐added aggregate in construction applications underscores the industry's ongoing challenge to get additional value from EAF slag recycling. Despite these challenges, the study highlights a great potential for increased value extraction from EAF slag recycling. Beyond conventional applications as a clinker material for the cement industry, the review explores modern technologies for steelmaking slag recycling, revealing options for recovering valuable metals such as Cr, V, Mo, and Fe through methods such as leaching, reduction, and oxidation.
... The pseudo-second-order model describes the adsorption reaction rate with energetically heterogeneous sites, considering a chemisorption model. 24 In the kinetic parameters of the Elovich model, an increase in the adsorption rate constant (α) is observed when the alumina sphere is coated with HAp, which indicates that the adsorption process is favored by the HAp coating. On the contrary, the desorption constant (β) has very low values, which indicates that there is little or no desorption. ...
... The Temkin model describes adsorption with a uniform binding energy distribution and assumes that the heat of adsorption of all molecules in the adsorption layer decreases linearly with the coating due to adsorbent−adsorbate interactions. 24,26 The maximum adsorption capacity of Cd 2+ on the alumina spheres was 59.97 mg/g, which was dominated by electrostatic interactions, covalent bonds, and cooperative adsorption, as described in a previous work. 13 The Cd adsorbent capacity increased 1.62 times with the hydroxyapatite coating, obtaining a maximum adsorption of 89.37 mg/g with a respective adsorption of 158 ppm of Cd 2+ . ...
Heavy metals can act as selective agents in the development and proliferation of antibiotic-resistant bacteria through a process called coselection. In the year 2050, an estimated 10 million deaths will be caused by antibiotic-resistant bacteria; therefore, the presence of heavy metals in bodies of water represents an environmental and sanitary threat that requires efficient treatment processes and/or materials for their removal. In the present study, the effect of the hydroxyapatite coating on the adsorbent capacity of cadmium in alumina spheres was evaluated. The hydroxyapatite coating on the alumina sphere increased the surface area from 0.66 to 0.96 m²/g and the number of acid sites from 0.064 to 0.306 meq/g and displaced the IEP of hydroxyapatite from 5.37 to 4.2, increasing the Cd²⁺ adsorbing capacity from 59.87 mg/g to 89.37 mg/g and promoting adsorption by surface complexation. Alumina-hydroxyapatite spheres stand out for their improved adsorbent properties and easy handling, which positioned this material as a potential alternative in adsorption processes.
... Around 450 million tons of these smelter slags are produced every year in different parts of the world [24][25][26]. Most of them are disposed of in landfills, with the remainder handled in an unplanned way [4,11]. ...
... Two types of slag are very common. These are slags from the ferrous metallurgical industry and slags from the nonferrous metallurgical industry [5,24]. As discarded waste products, the world produces approximately 320 to 384 million tons of iron and steel slags, 15 million tons of nickel smelter slags, 15 million tons of copper slags, and 19 million tons of ferromanganese slags each year [6,25,26]. ...
... Different studies reported As removal from water and wastewater by recycling smelter slags in different environmental conditions. According to Borrayo et al. [24], the maximum removal of As by steel slags was found to be 1.99 mg/g. The slags can be used in well-mixed batch reactors to perform an adsorption method for As removal from contaminated water and wastewater [7,24]. ...
Slags from the ferrous and nonferrous metallurgical industries have been used to treat toxic contaminants in water and wastewater. Using slag as a recycling or renewable resource rather than a waste product has environmental and economic benefits. Recycled smelter slags can be used in both in situ and ex situ treatment. However, their application has some limitations. One of the challenges is how to handle spent slag adsorbents, as they contain the accumulation of solid waste loaded with high concentrations of toxic contaminants. These challenges can be overcome by regeneration, recycling, reuse, and immobilization treatment of spent slag adsorbents. The present paper explored the scientific and technical information about the composition, reaction mechanisms, adsorption capacity, and opportunities of recycled slags while adsorbing toxic compounds from contaminated water. It comprehensively reviewed the current state of the art for using smelting slags as sustainable adsorbents for water and wastewater. The study revealed that ferrous slags are more effective in removing a wide range of toxic chemicals than nonferrous smelter slags. It investigated the necessary improved approach through the 5Rs (i.e., reduce, reuse, recycle, remove, and recover) using smelter slags as reactive materials in ex situ and in situ treatment.
... The pH of the solution should be basic for the optimum outcomes and finally, the adsorption process takes place. A nucleophilic reaction happens between the ions of arsenites or arsenates and the ions of OH that are present on the surface of the adsorbent [48] Biochar is a porous, carbon-rich substance that is produced by heating organic biomass at temperatures between 300°C and 800°C in the absence of oxygen using plant-or animal-based feedstocks (such as pinewood, oak wood, perilla leaf, and others). In particular, by adjusting the pH of the solution, activated biochars can change their surface charge, which can be positive or negative. ...
Arsenic (As) contamination is one of the most serious forms of environmental pollution caused by human activities. Numerous concerned authorities around the world are now focusing on the As decontamination. The technologies for removing As have grown in importance since it is understood that even very low amounts of As in drinking water can have serious negative effects on health. This review provides a thorough explanation of the various well-established and cutting-edge technologies, including ion exchanges, adsorption, membrane process, electrokinetic processes, electrocoagulation, precipitation, phytoremediation, inexpensive useful methods, emerging remedial techniques, nanoparticles and nano based adsorbents that can be used to remove As impurities from the drinking water. The low cost, simplicity and easy operational mechanism of adsorption technique gained much attention globally, however, it is also believed that nanotechnology will be essential in supplying clean, inexpensive water to suit human needs.
... The most common methods for determining elemental composition of slags are X-ray fluorescence analysis (XRF) and energy-dispersive X-ray analysis (EDX) [33]. EDX is a rapid method and allows you to evaluate the composition of certain areas of the sample surface, but the determination of elemental composition is only possible for the upper layers of the sample. ...
Blast furnace slag is a key large-tonnage waste product of metallurgical production, which is considered to be a promising alternative material in construction. In order to determine the scope of potential use of slag as a marketable product, it is necessary to study its structure and composition, which is determined by means of modern analytical instrumental methods. This paper analyzes the application of Fourier transform infrared spectroscopy (FTIR) and chemometrics methods to develop calibration models for identifying pelletized slag by elemental composition. In a comparative analysis of FTIR-spectra of slag the characteristic frequencies of absorption bands responsible for the content of calcite, silicates and aluminosilicates in the composition of samples were determined. Multivariate regression methods (principal components regression, partial least squares regression) and data of elemental composition results by EDX method were used to develop calibration models for determining elemental composition of granulated blast furnace slag. Using the developed PLS models with high performance (R² from 0.91 to 0.96 for different components), the prediction of the elemental composition (Ca, Si, O, Mg) of the test sample was carried out and a low deviation of the prediction in contrast to the EDX reference data was obtained. The use of PLS calibration models for rapid and nondestructive determination of the quantitative content of components of the composition of granulated blast furnace slag has been proposed.
