Adsorption and kinetic studies of hexavalent chromium by dehydrated Scrophularia striata stems from aqueous solutions

Dehghani, Mansooreh; Nozari, Majid; Golkari, Iman; Rostami, Nasrin; Shiri, Marziyeh Ansari

doi:10.5004/dwt.2018.22953

Cited by 10 publications

(4 citation statements)

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“…As the amount of TGWAC and NGAC increased from 0.1 to 0.4 g L -1 , the removal rate of Ni(II) gradually increased from 98.2% to 99.47%. This occurred because the effective adsorption sites increased with the increased amount of adsorbent [30]. When the adsorbent dose was continuously increased to 0.5 g L -1 , the removal rate of Ni(II) tended to be stable.…”

Section: Effect Of Adsorbent Dose On Twgac and Ngacmentioning

confidence: 99%

Performance evaluation of adsorptive removal of Ni(II) by treated waste granular-activated carbon and new granular-activated carbon

Wang¹,

Wang²,

Xu³

et al. 2019

Desalination and Water Treatment

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Granular-activated carbon is a commonly used adsorbent in water treatment. It can be reused by regeneration when saturated, but there are limits to the number of regenerations in actual engineering. This study created a simple and economical treatment method allowing for the reuse of waste granular-activated carbon (WGAC) that approaches the regeneration limit. The adsorption kinetics, equilibrium, and thermodynamics of Ni(II) onto the treated waste granular-activated carbon (TWGAC) and the new granular-activated carbon (NGAC) were studied. The N 2 adsorption/ desorption isotherms, zeta potential, SEM, energy-dispersive spectrometry and FTIR spectra were used to characterize and compare the NGAC and TWGAC. Analysis revealed that the structure of WGAC was severely damaged, but the adsorption capacity and adsorption mechanism after treatment were similar to those of NGAC. Experimental data showed that the pseudo-second-order kinetic model and the Freundlich isothermal model had high correlation coefficients (R 2 > 0.99). The maximum adsorption capacity of TWGAC and NGAC was 138.9 and 123.5 mg g-1. Thermodynamic parameters, including the negative values ΔG, positive values ΔH, and positive value ΔS, indicated that the current adsorption processes of TWGAC and NGAC were feasible, spontaneous and endothermic. After three cycles, TWGAC's removal rate for Ni(II) remained as high as 95.3%.

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Section: Effect Of Adsorbent Dose On Twgac and Ngacmentioning

confidence: 99%

Performance evaluation of adsorptive removal of Ni(II) by treated waste granular-activated carbon and new granular-activated carbon

Wang¹,

Wang²,

Xu³

et al. 2019

Desalination and Water Treatment

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“…Yarrowia lipolytica 70562 15 181.83 Dsss 12 Andesite Present Plagioclase 25 makes up at least 65% of the feldspar in the rock, with less than 20% of the volume being quartz and 10% being feldspathoid. Chemically speaking, andesite is described as volcanic rock that contains between 57% and 63% silica and no more than 6% alkali metal oxides 26 .…”

Section: Adsorbentsmentioning

confidence: 99%

Adsorption of mercury(II) to volcanic rock: Characteristics, equilibrium, thermodynamics, regeneration and wastewater treatment applications

Khedr,

Elwakiel,

Halawia

et al. 2024

Preprint

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Andesite was employed to effectively extract mercury(II) in aqueous solution. After evaluating its characteristics, andesite was characterized applying modern techniques such as FTIR, BET and TGA methods. The study employed SEM and TEM measurements to analyze the variation in the surface shape and crystallinity of the metal due to adsorption. Adsorbent quantity (0.05-1) mg, contact time (5-60) minutes, pH (2–10), temperature (25–60)°C, and dose [2.738, 4.413, 12.550, 15.520, 39.95] ppb, all affect the amount of removal that increases with the increase in contact time, pH, dose and temperature, but drops as the metal ion concentration rises . The ideal values for contact time, pH, metal ion concentration, dose, and temperature were found to be, respectively, 30 minutes, 8, 15.520 ppb, 0.4 mg, and 40°C. The calculation of thermodynamic parameters, including ΔH, ΔG, and ΔS, was imperative in establishing that the mechanism of heavy metal adsorption on andesite was endothermic, exhibiting a physical nature that escalated with temperature rise. The Freundlich adsorption equation's linear form is matched by the adsorption of mercury(II) on andesite, constant n was 1.85, 1.06, 1.1, and 1.1, whereas the Langmuir constant qm was found to be 1.85, 2.41, 3.54, and 2.28 mg/g at 25°C to 60°C. Furthermore, adsorption follows a pseudo-second-order, rate constant was 3.08, 3.24, 3.24 and 13 under the identical temperature conditions, as opposed to a first-order, rate constant was 4, 3, 2.6, and 2. Hg2+, NH4+, Cl-, Br-, NO3-, SO42-, Na+, K+, H2S, and CH3SH were all extracted from wastewater by this application.

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“…Thus, there is a need to determine an efficient, cost effective, and eco‐friendly solution, which maintains adsorbent structure through the regeneration 9 . Although studies have used various adsorbents to remove toxic metals from water, 10–13 regenerability has only been considered by the limited number of publications 12–17 …”

Section: Introductionmentioning

confidence: 99%

“…Thus, there is a need to determine an efficient, cost effective, and eco-friendly solution, which maintains adsorbent structure through the regeneration. 9 Although studies have used various adsorbents to remove toxic metals from water, [10][11][12][13] regenerability has only been considered by the limited number of publications. [12][13][14][15][16][17] Fly-ash derived zeolites have been attracted great attention due to relatively less expensive synthesis and recycling waste from coal power plants, reinforcing sustainability.…”

mentioning

confidence: 99%

Regenerability of fly‐ash derived zeolite NaP1: Evaluation via copper recovery

Ankrah

Tokay

Snape

2022

Engineering Reports

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Effective regeneration of adsorbents is considered as one of the essential qualities for commercial use. However, most of the studies have only reported the adsorption properties and overlooked the reuse of adsorbents. In this study, we determined the regenerability and reusability of fly-ash derived zeolite (FADZ) NaP1. These adsorbents have become popular to remove pollutants from water, including toxic metals, since they are less expensive, compared to their counterparts, and can be synthesized from a waste product. We evaluated the efficiency of copper (Cu 2+ ) ions recovery from water using multiple regeneration solutions due to medium adsorption selectivity towards Cu 2+ . We determined the time required for the regeneration using acid, base, and salt solutions. The suitable pH and solution while maintaining the structure of the zeolite were studied. Up to 90% recovery was achieved via three successive regenerations, each taking 3 h using 3 M KCl and 3 M NaCl solutions. X-ray diffraction (XRD) and fluorescence showed changes in structure after regeneration at pH < 5 and contact time <6 h. The desorption kinetics using KCl solutions can be described by pseudo-second order model. Freundlich model represents the desorption of Cu 2+ ions better than the Langmuir model due to regression coefficient (R 2 ) values in the range of 0.998-1.0. Results suggest a strong ion exchange mechanism as the main driving force for desorption. The type of anions (such as Cl − and OH − ) in solution influences regeneration in addition to the exchanging cation.

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Adsorption and kinetic studies of hexavalent chromium by dehydrated Scrophularia striata stems from aqueous solutions

Cited by 10 publications

References 0 publications

Performance evaluation of adsorptive removal of Ni(II) by treated waste granular-activated carbon and new granular-activated carbon

Performance evaluation of adsorptive removal of Ni(II) by treated waste granular-activated carbon and new granular-activated carbon

Adsorption of mercury(II) to volcanic rock: Characteristics, equilibrium, thermodynamics, regeneration and wastewater treatment applications

Regenerability of fly‐ash derived zeolite NaP1: Evaluation via copper recovery

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