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Single-and multi-component isotherm parameters for metal ions removal

Single-and multi-component isotherm parameters for metal ions removal

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The use of banana peel as a sustainable and low-cost precursor for the fabrication of effective biochar was exploited. Here, calcined magnetic biochar (CMB) was fabricated and characterized. CMB possesses surface acidic functional groups (-OH and COO −), porous structures, high saturation magnetization (39.55 emu/g), and larger surface area than th...

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A high-efficiency layered double oxide-biochar hybrid (MnFe-LDO-biochar) catalyst was successfully synthesized by the co-precipitation-calcination process and used to effectively remove tetracycline (TC) pollution. The characterization results verified that MnFe-LDO-biochar possesses a specific surface area of 524.8 m 2 g − 1 , appropriate bandgap...

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... Because of its porous structure, large specific surface area (SSA) and high functional group content, biochar has been widely used as a low-cost adsorbent to efficiently remove heavy metals from polluted waters [17][18][19]. Recently, biochar is commonly modified in various ways to improve its SSA and functional group content, so as to further improve its high metal adsorption capacity [10,20,21]. ...
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Biochar has been widely used as an adsorbent to remove cadmium (Cd) from polluted waters because of its high specific surface area and rich functional groups. Efforts have been made to modify biochar to further improve its metal adsorption capacity. In this work, biochars prepared using cotton straw, corn straw, and rice husk, were first modified with ball-milling and iron/manganese (Fe/Mn) oxides to prepare Fe/Mn binary metal oxide-ball milled biochar (Fe/Mn-BMBCs). Compared with pristine biochars, Fe/Mn-BMBCs had rough surface with deposits of Fe/Mn oxide nanoparticles, larger specific surface areas (226.50–331.50 m² g⁻¹), and more oxygen-containing functional groups. The adsorption kinetics and isotherm of Cd²⁺ on both the pristine biochars and Fe/Mn-BMBCs were best described by the pseudo-second-order model and the Langmuir model, respectively, indicating that the adsorption of Cd²⁺ was primarily monolayer chemisorption. The adsorption capacities of Fe/Mn-BMBCs were 4.8–6.1 times higher than those of pristine biochars, respectively. When the solution ionic strength and valence of coexisting cation increased, the adsorption capacities of Fe/Mn-BMBCs decreased because of cation competition. In contrast, the adsorption capacities of Fe/Mn-BMBCs increased with the increasing solution pH value. Complexation with oxygen-bearing functional groups, ion exchange, Cd²⁺-π interaction and chemical precipitation were the main mechanisms of Cd²⁺ adsorption on Fe/Mn-BMBCs. Therefore, Fe/Mn-BMBCs prepared with different agricultural wastes have different Cd²⁺ adsorption capacities and can be used as environmentally friendly and effective adsorbents for Cd²⁺ removal from aqueous media.
... Pollution of water due to ever growing urbanization and industrialization by toxic metals such as chromium (Cr), cadmium (Cd), mercury (Hg), copper (Cu), lead (Pb), manganese (Mn), arsenic (As) and nickel (Ni) is alarming (Oladipo et al., 2019). These toxic metals are detrimental to living organisms (Ayub et al., 2018;Nimibofa et al., 2017). ...
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This study aims to remove Copper (Cu(II)) and Chromium (Cr(VI)) from aqueous solution using activated carbon (AC) from fennel seeds and potassium permanganate (KMnO4) treated fennel seeds. The activated carbon adsorbents were prepared from fennel seeds at different temperatures (500, 600 and 700°C). These adsorbents were designated as FS-500, FS-600 and FS-700. Each adsorbent was then chemically treated with KMnO4 solution to develop activated adsorbents, KMFS-500, KMFS-600 and KMFS-700. These six adsorbents were used for the binary adsorption of Cu(II) and (Cr(VI)) from an aqueous solution. The adsorbents were characterized by FTIR, SEM, UV-Vis and XRD. FTIR confirmed the presence of oxygen functional groups such as hydroxyl (-OH), carboxyl (-COOH) and carbonyl (-C = O) on the surface of the adsorbents. XRD confirmed a decrease in crystallinity as the temperature increased. SEM images showed that the morphology of the adsorbents was porous. KMFS-700 and FS-700 adsorbed more Cu(II) and Cr(VI) ions than KMFS-600, KMFS-500, FS-600 and FS-500. The maximum adsorption capacities for Cu(II) and Cr(VI) by FS-700 were 19.886 and 8.510 mg/g; for FS-600, it was 15.423 and 1.202 mg/g, and for FS-500, it was 16.921 and 1.722 mg/g, respectively. The maximum adsorption capacities for Cu(II) and Cr(VI) by KMFS-700 were 19.786 and 10.572 mg/g; for KMFS-600 it was 15.735, 8.109 mg/g, and for KMFS-500, it was 17.648 and 3.479 mg/g, respectively. All the adsorbents showed a stronger affinity for Cu(II) than Cr(VI). Kinetic studies showed that Cu(II) and Cr(VI) adsorption followed a pseudo-second-order reaction confirming that a chemical process controlled adsorption.
... It is concluded that in the case of MB and SO dye adsorption, the % removal efficiency was enhanced from 89 to ~ 96%, 86 to 97.9%. This is because of the enhancement in the surface area of the adsorbent, which provides additional functional groups and more active sorption sites (Oladipo 2019). In case of CV dye, the % removal efficiency was increased from 95.77 to 98.27% by increasing the adsorbent loading from 0.005 to 0.01 g. ...
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In this study, a Pennisetum glaucum raw material (RM) based green bio-composite adsorbent containing 0.5% functionalized carbon nanotube (0.5% CNT + RM) was synthesized. The morphology and physicochemical properties of the bio-composite were explored using different techniques, such as Field emission scanning electron (FESEM), X-ray crystallography (XRD), Fourier transform infrared spectroscopy (FTIR), Differential scanning calorimetry (DSC), and Energy-dispersive X-ray spectroscopy (EDX). The adsorption efficiency of prepared bio-composite adsorbents was investigated for the efficient and effective removal of three cationic dyes such as methylene blue (MB), safranine O (SO), and crystal violet (CV) from single and multi-component systems. Batch adsorption experiments were performed to investigate the influence of different operational factors such as solution pH, initial dye concentration, adsorbent dosage, temperature, and contact time on the adsorption efficiency of dyes. In a single component, the process kinetics and adsorption behaviour of the adsorbent were well explained by the pseudo 2nd order kinetic model and Langmuir isotherm, giving a higher monolayer adsorption capacity of value, i.e., 510.96, 169.70, and 98.77 mg g⁻¹ for CV, SO, and MB dyes, respectively, at neutral pH conditions. The modified Langmuir isotherm model was employed to investigate the inhibiting effects of dyes in binary systems (MB + CV; CV + SO; SO + MB) and ternary systems (MB + CV + SO), which revealed the competitive behaviour of dyes. The adsorption process was feasible, exothermic, and physical in nature, involving H-bonding, π-π and electrostatic interactions. The regeneration studies of bio-composite showed excellent recovery capability, retaining their good adsorption efficiency after ten cycles of regeneration. Overall, a low-cost 0.5% CNT + RM bio-composite with excellent adsorption capacity in single and multi-component systems indicates its good potential for practical applications. Graphical abstract
... The linear forms of the pseudo-first-order, pseudo-second-order kinetic models, and intra-particle diffusion model are expressed as Equations (4)-(7) [55][56][57] : ...
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An Unpredictable rise in greenhouse gas (GHG) emissions is a primary concern to the global scientific community. It is directly related to the rapid expansion of the human population and is associated with the immense energy demand. The combustion of hydrocarbon fuels in internal combustion (IC) engines releases a large amount of carbon dioxide (CO2), which is one of the causes of GHG emissions. Mitigation of CO2 emissions is a significant challenge to the world. Although several researchers have focused on capturing CO2 from power plants, some researchers have taken initiatives in recent times to capture CO2 in IC engines. This study particularly explored the possibility of using a biomass based‐adsorbent to capture CO2 in the exhaust of a diesel engine. Initially, activated carbon was obtained from palm shells by adopting the preparation methods such as (i) carbonization and (ii) chemical activation. Then, the produced activated carbon was analyzed to examine its physico‐chemical characteristics and surface textural properties by adopting characterization techniques. The adsorbent sample was loaded in an in‐house fabricated adsorption chamber which was attached to the exhaust of the test engine. The performance of palm shell‐based activated carbon was evaluated as a potential adsorbent for CO2 capture when the engine was operated with two distinct fuels, (i) 100 % diesel (D100) and (ii) an optimum biodiesel‐diesel blend (JME20) comprising 80 % D100 and 20 % Jatropha Methyl Ester (JME). The experimental results showed that an average of about 30 % and 37 % of CO2 was captured by using palm shell‐based adsorbent in D100 and JME 20 operations, respectively. This article is protected by copyright. All rights reserved.
... Although activated carbon is the most widely used commercial adsorbent, multiple investigations of silver removal by activated carbon or other synthetic and natural adsorbents challenged the commercialisation of such technology due to the cost-effectiveness and environmental footprint [27]. Biochar has been successfully used to remove numerous contaminants, such as antibiotics removal [31,32], phenols [33][34][35], and heavy metals [36,37] from wastewater. For example, a study investigated the application of biochar to adsorption of different heavy metals like copper, zinc and lead from the aqueous phase. ...
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... The FTIR spectrum of bio-sorbent ( Fig. 2b) at 3416 cm −1 corresponds to the -OH of hydroxyl functional groups. The peak at 1743 cm −1 is probably related to the stretching vibration of carboxyl groups or C=O of lipids (Oladipo et al. 2019;Toumi et al. 2018b). The band at 1380 cm −1 is attributed to the symmetrical stretching vibration CH 2 (Allwar, 2020). ...
... The FTIR spectrum of bio-sorbent ( Fig. 2c) after adsorption shows that some peaks are shifted to different wavenumbers or disappear after the adsorption of the PCs, indicating that the functional groups present on the adsorbent are involved in the adsorption of phenol (Oliveira et al. 2016). Notably, the carboxyl group shifted to 1745 cm −1 , suggesting the involvement of the carboxyl group during the adsorption process (Blazquez et al. 2010;Oladipo et al. 2019). Furthermore, the peak of the -OH stretching vibration is shifted to 3425 cm −1 , and this shift confirms that the -OH group was responsible for the adsorption of phenol onto the bio-sorbent (Yuney et al. 2020). ...
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Olive oil mill wastewater (OMWW) poses an undeniable environmental problem due to its high organic loads and phenolic compound (PC) content. This study determined the optimal conditions for preparing a new bio-sorbent from olive pomace (OP) and the adsorptive treatment of OMWW by this bio-sorbent. The activation reaction was performed with hydrogen peroxide. The results of the combination effect optimization of the three preparation variables, the activation temperature (°C) X1, the activation time (min) X2, and the impregnation ratio X3, are presented by the response surface methodology (RSM). The maximum adsorption capacity was obtained at an activation time of 240 min, a temperature of 80 °C, and a ratio equal to 6.2:1. The bio-sorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometer (XRD). The adsorption process performance of this bio-sorbent was examined in batch (phenol solution) and fixed-bed columns (real effluent of OMWW). An adsorption capacity of 789.28 mg g⁻¹ and 643.92 mg g⁻¹ has been achieved for 4000 mg L⁻¹ concentration of PCs, respectively, for batch and fixed-bed column essays. The adsorption isotherm and kinetics were consistent with the Langmuir and pseudo-second-order models. Therefore, the Thomas model best fits the fixed-bed column experimental data. The bio-sorbent gave a high desorption percentage of PCs, which was above 60% using HCl (0.1M). Graphical abstract
... Unfortunately, few studies have been carried out to evaluate the effectiveness of Fe-BC composites on Hg 2+ elimination. For example, banana peels were treated with Fe salts to produce Fe-modified BC (500 °C) for the efficient removal of Hg 2+ (Oladipo et al. 2019). The porous structures, abundance of active functional groups, high magnetization (39.55 emu g −1 ), and high specific surface of 323.2 m 2 g −1 , promoted Hg 2+ sorption (83.4 mg g −1 ) by the modified BC over the original BC (45.5 mg g −1 ) at pH 6.0. ...
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Biochar (BC) has gained attention for removal of toxic elements (TEs) from aqueous media; however, pristine biochar often exhibits low adsorption capability. Thus, various modification strategies in BC have been developed to improve its removal capability against TEs. Nanoscale zero-valent iron (nZVI) and iron oxides (FeOx) have been used as sorbents for TE removal. However, these materials are prone to agglomeration and also expensive, which make their usage limited for large-scale applications. The nZVI technical demerits could be resolved by the development of BC-based composite sorbents through the loading of nZVI or FeOx onto BC surface. Nano zero-valent iron modified BC (nZVIBC), FeOx-modified BC (FeOxBC) have attracted attention for their capability in removing pollutants from the aqueous phases. Nonetheless, a potential use of nZVIBC and FeOxBC for TE removal from aqueous environments has not been well-realized or reviewed. As such, this article reviews: (i) the preparation and characterization of nZVIBC and FeOxBC; (ii) the capacity of nZVIBC and FeOxBC for TE retention in line with their physicochemical properties, and (iii) TE removal mechanisms by nZVIBC and FeOxBC. Adopting nZVI and FeOx in BC increases its sporptive capability of TEs due to surface modifications in morphology, functional groups, and elemental composition. The combined effects of BC and nZVI, FeOx or Fe salts on the sorption of TEs are complex because they are very specific to TEs. This review identified significant opportunities for research and technology advancement of nZVIBC and FeOxBC as novel and effective sorbents for the remediation of TEs contaminated water.
... The pollutant is adsorbed at the surface of the flocs electrochemically formed via several mechanisms such as the physicochemical process in the EC process. Various linearized kinetic models (commonly used equations reported elsewhere; Ouaissa et al., 2014;Oladipo et al., 2019;Kim et al., 2020) were used to characterize the adsorption kinetics onto produced flocs to better understand the mechanisms of the TC and TC-Ni adsorption processes. The linear regression correlation coefficient values (R 2 ) and other error functions (χ) (Oladipo et al., 2019) were used to determine the most accurate model. ...
... Various linearized kinetic models (commonly used equations reported elsewhere; Ouaissa et al., 2014;Oladipo et al., 2019;Kim et al., 2020) were used to characterize the adsorption kinetics onto produced flocs to better understand the mechanisms of the TC and TC-Ni adsorption processes. The linear regression correlation coefficient values (R 2 ) and other error functions (χ) (Oladipo et al., 2019) were used to determine the most accurate model. ...
... The second-order model assumes that two reactions take place, one in series and one in parallel; the first is fast and reaches equilibrium quickly, while the second is slower and might last for a long time (Ouaissa et al., 2014). The pseudo-first order implies that physisorption has a role in pollutant adsorption, while the pseudo-second-order is based on the chemisorption mechanism (Oladipo et al., 2019;Kim et al., 2020). ...
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In discharged water, antibiotics and heavy metals frequently coexist, forming stable and recalcitrant complexes. Environmental concerns about how to efficiently treat this type of pollution are growing. Using Fe and Al electrodes, electrocoagulation (EC) was applied to remove tetracycline (TC) as a single pollutant as well as TC-nickel ions in a binary mixture from water. The effects of critical variables and the TC-Ni molar ratio (1:1, 1:2, and 2:1) were studied. The Fe electrode achieved 99.3% TC removal after 60 min in a single pollutant system containing 15 mgL⁻¹ of TC, while the Al electrode achieved 99.8% removal in 20 min at optimal conditions. The EC process demonstrated excellent electrodegradation efficiency towards TC-Ni complexes. When the TC to Ni²⁺ ratio was 1:1 and 1:2, respectively, TC elimination was 100% in 10 min and 99.6% in 20 min. We noted that a sufficient amount of Ni²⁺ could increase TC decomposition by electrocatalysis. The amount of hydrogen gas produced after treatment of a 0.2 L TC solution alone is 22.2–13.99 mol m⁻³, whereas it was 27.2–40.8 mol m⁻³ in the TC-Ni binary mixture, which can generate more than 35% of the electrical energy needed to power the EC system. To evaluate the generated sludge, FTIR analysis was performed.
... The extensive studies have been carried out on the development of such magnetic nanomaterials [3]. Among various magnetic nanomaterials as adsorbents, a hybrid magnetic nanocomposite (HMNCs) has gained wide range of attention due to their excellent physiochemical, surface, magnetic properties, and chemical and mechanical stabilities [4][5][6]. ...
... It is known that physical properties of wastewater, especially pH is greatly affected due to the presence of pollutants [5,6]. Sometimes, the pH of the wastewater rises making the water alkaline, and sometimes the water becomes acidic due to the low pH. ...
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This study reports synthesis and utilization of Fe3O4@date seeds powder to remove methylene blue from water. The adsorbent has been produced by a simple co-precipitation method, in which Fe3O4 nanoparticles are grown on date seeds powder. Different chemical functional groups were found on surface of the prepared bio-adsorbent. The size of the grown Fe3O4 nanoparticles was observed to be around 5 nm and confirmed their magnetic character via VSM measurement. Several non-linear adsorption isotherm models such as Langmuir, Freundlich, and Redlich-Peterson were obtained for methylene blue dye adsorption, and it was observed that the Freundlich isotherm is the best fitted model. The monolayer adsorption capacity calculated from Langmuir isotherm was 76.652 mg g⁻¹ at 27 ºC. The kinetic models (pseudo first order and pseudo second order) were also studied for methylene blue adsorption and the pseudo second order is the best fitted model in the present investigation. The methylene blue adsorption isotherm and kinetic study suggested that the current adsorption process was carried out by electrostatic interactions between the functional groups on the surface of the Fe3O4@date seeds powder and the dye, and the rate determining step was intraparticle diffusion. This entire study has been systematically explained through comparative study of literature. This study proves that the developed adsorbent is bio-degradable, inexpensive, and efficient for dye removal, which recommends increasing the production of natural bio-adsorbents in the future for water purification.
... The FTIR spectrum of bio-sorbent ( Fig. 2b) at 3416 cm −1 corresponds to the -OH of hydroxyl functional groups. The peak at 1743 cm −1 is probably related to the stretching vibration of carboxyl groups or C=O of lipids (Oladipo et al. 2019;Toumi et al. 2018b). The band at 1380 cm −1 is attributed to the symmetrical stretching vibration CH 2 (Allwar, 2020). ...
... The FTIR spectrum of bio-sorbent ( Fig. 2c) after adsorption shows that some peaks are shifted to different wavenumbers or disappear after the adsorption of the PCs, indicating that the functional groups present on the adsorbent are involved in the adsorption of phenol (Oliveira et al. 2016). Notably, the carboxyl group shifted to 1745 cm −1 , suggesting the involvement of the carboxyl group during the adsorption process (Blazquez et al. 2010;Oladipo et al. 2019). Furthermore, the peak of the -OH stretching vibration is shifted to 3425 cm −1 , and this shift confirms that the -OH group was responsible for the adsorption of phenol onto the bio-sorbent (Yuney et al. 2020). ...
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Olive oil mill wastewater (OMWW) poses an undeniable environmental problem due to its high organic loads and phenolic compounds (PCs) content. This study determined the optimal conditions for preparing a new bio-sorbent from olive pomace (OP) and the adsorptive treatment of OMWW by this bio-sorbent. The activation reaction was performed with hydrogen peroxide. The results of the combination effect optimization of the three preparation variables: the activation temperature (°C) X 1 , the activation time (min) X 2 and the impregnation ratio X 3 , are presented by the response surface methodology (RSM). The maximum adsorption capacity was obtained at activation time 300 min, temperature 80 °C and ratio equal to 6.2:1. The bio-sorbent was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) and X-ray diffractometer (XRD). The adsorption process performance of this bio-sorbent was examined in batch and fixed-bed columns. An adsorption capacity of 446 mg g ⁻¹ has been achieved for 4000 mg L ⁻¹ concentration of PCs. The adsorption isotherm and kinetics were consistent with the Langmuir and pseudo-second-order models. Therefore, the Thomas model best fit the fixed bed column experimental data. The bio-sorbent gave a high desorption percentage of PCs, which was above 70% using HCl (0.1M).