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![MB removal by various adsorbents at 100 mg/L dye concentration, 40 ∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^\circ{\rm C} }$$\end{document}, and 1 g/L dosage](publication/354292329/figure/fig5/AS:11431281180808670@1691721206486/MB-removalby-various-adsorbents-at-100mg-L-dye-concentration-40.png)
MB removal by various adsorbents at 100 mg/L dye concentration, 40 ∘C\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$${^\circ{\rm C} }$$\end{document}, and 1 g/L dosage
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The main challenges in wastewater treatment using adsorbents are the selection, development, and characterization of the absorbents. In this study, activated carbons (ACs) were prepared through chemical activation with phosphoric acid, followed by carbonization of banana root (BR). Proximate, ultimate, BET, FTIR, and FE-SEM analyses were employed t...
Citations
... synthesized AC from palmae shells which contains 47.23% carbon, 6.88% hydrogen, 0.77% nitrogen, 44.86% oxygen, 0.25% sulphur, respectively and was successfully used as an adsorbent for mercury removal with highest adsorption efficiency of 93%. Similarly, Paluri et al (Paluri and Durbha, 2021) also reported AC derived from banana root with carbon, hydrogen, nitrogen and oxygen contents of 47.52%, 2.15%, 5.69% and 44.6%, respectively, and utilized for the adsorption of methylene blue. In a study by Altıntıg et al. (2017b), activated carbon was made from acorn shells with a fixed carbon content of 31.32% and an ash content of 8.46% for removal of methylene blue. ...
The present study aims to prepare an activated carbon (AC) adsorbent developed from Croton caudatus biomass material for the adsorption of 2-chlorophenol (2CP) from wastewater. Activated carbon was prepared by KOH activation at 2:1 impregnation ratio and 700 °C temperature using a muffle furnace under self-generated atmosphere for 2 h. Several techniques and methodologies such as proximate analysis, ultimate (CHNS)
analysis, BET, SEM, FT-IR, XRD and point of zero charge (pHpzc) have been used to determine physicochemical properties of the activated carbon. Batch adsorption studies were conducted for 2-chlorophenol adsorption and the optimum adsorbent dose, initial
concentration, pH, reaction time and temperature were found to be 0.15 g/L, 80 mg/L, 4, 60 min and 298 K, respectively. The equilibrium isotherm study for 2-chlorophenol adsorption was fitted well to the Langmuir model with the adsorption capacity of 53.619 mg/g, while the adsorption kinetics was best described by pseudo-second order model. Thermodynamic parameters demonstrated a negative ΔH (exothermic) and negative ΔG
(spontaneous) values. Studies on regeneration have shown that saturated carbon can be recycled up to five times with considerable removal efficiency. Besides, density functional
theory (DFT) simulation revealed that the adsorption of 2-chlorophenol onto AC adsorbent is favorable. Among the oxygen-containing functional groups, the carboxyl group appeared to have a greater influence on the adsorption process than the hydroxyl and carbonyl groups with the highest negative Eadsorption of − 42.16 kJ/mol. Furthermore, the inclusion of three oxygen-containing functional groups improves the adsorption capacity of AC towards 2CP relative to a single functional group.
... It is a highcost operation due to the use of steam or energy (Lewoyehu 2021). In contrast, the chemical activation process involves using chemical agents such as phosphoric acid, potassium hydroxide, and zinc chloride are used in the activation process (Paluri and Durbha 2021). Zinc chloride is a highly reactive agent, yielding a large SSA, but it is also highly toxic and corrosive. ...
In this work, the porosity enhancement of activated carbon by hydrolyzed lignin extracted from black liquor was studied. Lignin was treated before activation and carbonization using H2SO4 hydrolysis. The effects of H3PO4 concentration (0–66 wt%) as an impregnation agent and impregnation time (0–12 h) on the activated carbon were investigated. The cadmium adsorption capacity and isotherm were also determined. Results showed that the specific surface area (SSA) of activated carbon increased with increases in H3PO4 concentration and impregnation time. The maximum specific surface area of 1,653 m² per gram of hydrolyzed lignin was obtained using 66wt% H3PO4, impregnation time of 8 h, and carbonization at 500 °C. The adsorption isotherms of all samples were type-I, based on the International Union of Pure and Applied Chemistry. The pore size distribution of activated carbon prepared from lignin and hydrolyzed lignin without H3PO4 activation fell within the range of micropore. With 66wt% H3PO4 activation, activated carbon prepared from the lignin and the hydrolyzed lignin showed a mesoporous structure. The activated carbon prepared from hydrolyzed lignin in this study enhanced the Brunauer–Emmett–Teller-specific surface area up to 38.44% compared to that of non-hydrolyzed lignin. The maximum adsorption capacity of 9.50 and 9.69 mg of cadmium per gram of activated carbon prepared from lignin and hydrolyzed lignin, respectively, was achieved with 66wt% H3PO4 activation and 1 h of impregnations time. The adsorption isotherms of the cadmium fitted linearly with the Langmuir model. This study thus showed a promising production of highly porous activated carbon from the pulp and paper industry waste through a simple and low-cost method.
Graphical abstract
... In addition, phosphoric acid has fewer toxicological contaminants, less corrosion to the equipment used in the activation process, and H 3 PO 4 is a cheap activator agent [12,19]. Recently, H 3 PO 4 has been widely employed for AC preparation from various biomasses [20][21][22]. ...
Powdered activated carbon (AC) was prepared from biomass resource (Calicotome villosa) by H3PO4 activation. The optimal activation conditions were determined according to iodine number and the yield of prepared AC. The best activation conditions were obtained by using 100 mL of H3PO4 (50%wt) solution to activate 20 g of raw material, and by applying a pyrolysis temperature of 500 °C for 1 h. The highest iodine number 997 mg/g was obtained for the previous AC with an activation yield equal to 45%. The prepared AC was characterized by Fourier transform infrared spectroscopy (FTIR); X-ray diffraction (XRD); Brunauer, Emmett, and Teller (BET) surface area; scanning electron microscope (SEM); and the point-of-zero charge (pHPZC) method. AC showed high BET surface area (1051 m²/g) and pHPZC equals 2.50, indicating the suitability for cationic pollutants removal from aqueous solutions such as methylene blue (MB). The effect of AC dosage (25–150 mg), contact time (5–150 min), initial MB concentration (100–300 mg/L), and temperature (298–330 K) on MB adsorption was investigated in batch mode. Adsorption kinetics is described well by the pseudo-second order model with correlation coefficient R² = 0.9969, while the experimental adsorption isotherm data are better fitted by the Freundlich isotherm with adsorption intensity 1/n = 0.2109 which indicates the favorability of the adsorption. It was also found that the adsorption process is spontaneous and endothermic. The results showed that Calicotome villosa wood is a promising biomass precursor to develop an efficient activated carbon.
Graphical abstract
Natural resources including sand are one of the best approaches for treating dye-polluted wastewater. The SiO2/PANI-SDS nanocomposite was synthesized by self-assembly and intermolecular interaction. The physicochemical features of the SiO2/PANI-SDS nanocomposite were explored by FT-IR, XRD, SEM, TEM, EDX, and N2 adsorption–desorption techniques to be evaluated as an adsorbent for the MB. The surface area of the SiO2/PANI-SDS is 23.317 m²/g, the pore size is 0.036 cm³/g, and the pore radius is 1.91 nm. Batch kinetic studies at different initial adsorbate, adsorbent and NaCl concentrations, and temperatures showed excellent pseudo-second-order. Several isotherm models were applied to evaluate the MB adsorption on the SiO2/PANI-SDS nanocomposite. According to R² values the isotherm models were fitted in the following order: Langmuir > Dubinin–Radushkevich (D–R) > Freundlich. The adsorption/desorption process showed good reusability of the SiO2/PANI-SDS nanocomposite.
This article investigates the effect of adding HMIMBF4 (HM) to remove high amount of Cd2+ ions. Magnetic carbon nanotube (mCNT) was used as the main part of the adsorbent, and a Schiff base kind of N,N′-bis(salicylidene)ethylenediamine (ES) was applied to increase the selectivity of the method toward Cd2+ ions. X-ray diffraction patterns, Fourier-transform spectra, scanning electron microscopy pictures and alternative gradient force magnetometry characterize and confirm the interaction among the components, the presence of the materials, successful modification procedure and enough magnetic property. To better compare the adsorption applicability of HM, ES-mCNT and ES-HM-mCNT, the preconcentration condition was optimized for each adsorbent by the Plackett–Burman Design method. The swelling property confirms more affinity of ES-HM-mCNT toward Cd2+ ions, because it improved the dispersibility of the adsorbent into the sample solution. The reusability was 18 and 11 times for ES-mCNT and ES-HM-mCNT, respectively. Both adsorbents were durable for 60 days. Both systems follow the Langmuir isotherm adsorption model and the Pseudo-Second order kinetic model. Thermodynamic adsorption investigation shows that the adsorption in both systems is endothermic and spontaneous.
