Adsorption of Cr(VI) by Natural Clinoptilolite Zeolite from Aqueous Solutions: Isotherms and Kinetics

Abstract The main aim of this study was to evaluate the efficiency of natural zeolite for Cr(VI) removal from aqueous solutions. Following simple modification of adsorbent, the effect of operational parameters including pH (2–10), adsorbent dosage (2–20 g/L), contact time (5–150 min) and Cr(VI) concentration (10–50 mg/L) were studied according to one-factor-at-a-time procedure. The maximum Cr(VI) removal of 99.53% was obtained at initial pH of 2, contact time of 30 min, adsorbent dosage of 8 g/L and initial chromium concentration of 10 mg/L. The Freundlich isotherm was best fitted with experimental data (R2 = 0.951). Also, type 1pseudo second order kinetic model showed the most correlation (R2 = 1) with the experimental data. According to obtained results, it can be concluded that the application of clay-like adsorbents such as natural clinoptilolite zeolite can be considered as an efficient alternative for final treatment of effluents containing Cr(VI).

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Removal of Phosphate Ions from Aqueous Solutions by Adsorption onto Leftover Coal

Water ◽

10.3390/w12051381 ◽

2020 ◽

Vol 12 (5) ◽

pp. 1381

Author(s):

Dereje Tadesse Mekonnen ◽

Esayas Alemayehu ◽

Bernd Lennartz

Keyword(s):

Experimental Data ◽

Aqueous Solutions ◽

Contact Time ◽

Aqueous Media ◽

Effect Of Temperature ◽

Phosphate Adsorption ◽

Operational Parameters ◽

Solution Ph ◽

Retention Efficiency ◽

Set Up

High loadings of wastewater with phosphors (P) require purification measures, which can be challenging to realize in regions where the technical and financial frame does not allow sophisticated applications. Simple percolation devices employing various kinds of adsorbents might be an alternative. Here, we investigated the application of leftover coal, which was collected from Ethiopian coal mining areas, as an adsorbent for the removal of phosphate from aqueous solutions in a classical slurry batch set-up. The combined effects of operational parameters such as contact time, initial concentration, and solution pH on P retention efficiency was studied employing the Response Surface Methodology (RSM). The maximum phosphate adsorption (79% removal and 198 mg kg−1 leftover coal) was obtained at a contact time of 200 min, an initial phosphate concentration of 5 mg/L, and a solution pH of 2.3. The Freundlich isotherm was fitted to the experimental data. The pseudo second-order equation describes the experimental data well, with a correlation value of R2 = 0.99. The effect of temperature on the adsorption reveals that the process is exothermic. The results demonstrate that leftover coal material could potentially be applied for the removal of phosphate from aqueous media, but additional testing in a flow-through set-up using real wastewater is required to draw definite conclusions.

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Barium/Cobalt@Polyethylene Glycol Nanocomposites for Dye Removal from Aqueous Solutions

Polymers ◽

10.3390/polym13071161 ◽

2021 ◽

Vol 13 (7) ◽

pp. 1161

Author(s):

Somayeh Rahdar ◽

Abbas Rahdar ◽

Mostafa Sattari ◽

Laleh Divband Hafshejani ◽

Athanasia K. Tolkou ◽

...

Keyword(s):

Polyethylene Glycol ◽

Aqueous Solutions ◽

Removal Efficiency ◽

Contact Time ◽

Skin Diseases ◽

Freundlich Isotherm ◽

Order Kinetic ◽

Initial Concentration ◽

Adsorbent Dosage ◽

Order Kinetic Model

Dyes are known as one of the most dangerous industrial pollutants which can cause skin diseases, allergy, and provoke cancer and mutation in humans. Therefore, one of the important environmental issues is the effective removal of dyes from industrial wastewater. In the current work, BaFe12O19/CoFe2O4@polyethylene glycol (abbreviated as BFO/CFO@PEG) nanocomposite was synthesized and evaluated regarding its capacity for adsorptive removal of a model dye Acid Blue 92 (denoted as AB92) from aqueous solutions. The characteristics of the prepared nanocomposite was determined by tests such as X-ray diffraction (XRD), scanning electron microscope (SEM), vibration sample magnetization (VSM), and Fourier transform infrared spectroscopy (FTIR). The effects of conditional parameters including pH (2–12), initial concentration of dye (20–100 mg/L), adsorbent dosage (0.02–0.1 g/L) and contact time (0-180 min) on the adsorption of dye were investigated and then optimized. The results indicated that with the increase of the adsorbent dosage from 0.02 to 0.1 g/L, the removal efficiency increased from 74.1% to 78.6%, and the adsorbed amount decreased from 148.25 to 31.44 mg/g. The maximum removal efficiency (77.54%) and adsorption capacity (31.02 mg/g) were observed at pH 2. Therefore, the general optimization conditions revealed that the maximum adsorption efficiency of dye was obtained in condition of initial concentration of 20 mg/L, contact time of 1 h and pH of solution equal 2. The adsorption isotherm and kinetic data were evaluated using a series of models. The pseudo-second order kinetic model and Freundlich isotherm model show the best fitting with experimental data with R2∼0.999.

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Equilibrium and Kinetic Studies of Liquid Phase Adsorption of Methylene Blue Onto Phosphoric Acid Modified Bambaranut Shell

Acta Chemica Malaysia ◽

10.2478/acmy-2021-0007 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Eze Nkechinyere Olivia ◽

Ejimofor Samuel Adimchinobi ◽

Onuegbu Theresa Uzoma

Keyword(s):

Waste Water ◽

Methylene Blue ◽

Contact Time ◽

Average Pore Size ◽

Batch Process ◽

Blue Dye ◽

Order Kinetic ◽

Operational Parameters ◽

Average Pore ◽

Adsorbent Dosage

AbstractIn view of the global need to curb the effect of contaminants in waste water on our environment, the adsorption potentials of modified carbon from bambaranut (Vigna subterranean) shell was investigated for its efficiency in the removal of methylene blue from waste water. The adsorbent morphology and surface chemistry were established by Brunauer-Emmett-Teller (BET) determination and Scanning Electron Microscopy (SEM), as well as other standard laboratory procedures. The prepared material was used for the uptake of MB from aqueous solution in a batch process, using UV spectrophotometer Model 752 at 620nm to analyze for the residual dye concentration. The effect of operational parameters such as contact time, adsorbent dosage, initial dye concentration and pH were analyzed to determine the factors controlling the rate of adsorption. Results from the study showed that the active carbon prepared was a porous material, with surface area of 193 m2/g, average pore size of about 10.98nm, and pore volume of 0.530cm3/g. With increase in initial dye concentration from 15mg/l to 75mg/l, a decrease in percent adsorption from 95.4% to 72.19% was observed. Increase in adsorbent dosage (from 0.1g to 0.5g), contact time (from 5 min to 40 min) and pH from 2 to 10 resulted in increase in percent adsorption from 84.03% to 98.83%, 54.24% to 84% and 48.17% to 84.03% respectively. About 98.83% removal of MB dye was achieved after 20 min, at pH of 6, temperature of 27±2oC, 0.5g weight of adsorbent and initial concentration of 60mg/l of 50ml MB dye solution. Langmuir isotherm best fits the equilibrium adsorption data with R2 = 0.996; the adsorption intensity obtained from Freundlich model (n>1) and the energy of adsorption obtained from the D-R model (< 8kJ/mol) suggested that physisorption dominates the adsorption of methylene blue onto the prepared activated carbon. Adsorption kinetic data was best described using Pseudo second order kinetic model (R2 = 0.996), giving equilibrium rate constant (k2) of 7690g mg-1 min-1. The characteristic results showed that bambaranut shell can be employed as an alternative to commercial adsorbents in the removal of methylene blue dye from aqueous solutions and waste water.

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Process optimization and enhancement of pesticide adsorption by porous adsorbents by regression analysis and parametric modelling

Scientific Reports ◽

10.1038/s41598-021-91178-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Mohammad Hadi Dehghani ◽

Amir Hessam Hassani ◽

Rama Rao Karri ◽

Bahareh Younesi ◽

Mansoureh Shayeghi ◽

...

Keyword(s):

Kinetic Models ◽

Contact Time ◽

Xrd Analysis ◽

Effect Of Temperature ◽

Parametric Modelling ◽

Order Kinetic ◽

Operational Parameters ◽

Pesticide Concentration ◽

Adsorbent Dosage ◽

Pesticide Adsorption

AbstractIn the present study, the adsorptive removal of organophosphate diazinon pesticide using porous pumice adsorbent was experimentally investigated in a batch system, modelled and optimized upon response surface methodology (RSM) and artificial neural network-genetic algorithm (ANN-GA), fitted to isotherm, kinetic and thermodynamic models. The quantification of adsorbent elements was determined using EDX. XRD analysis was utilized to study the crystalline properties of adsorbent. The FT-IR spectra were taken from adsorbent before and after adsorption to study the presence and changes in functional groups. The constituted composition of the adsorbent was determined by XRF. Also, the ionic strength and adsorbent reusability were explored. The influences of operational parameters like pH, initial pesticide concentration, adsorbent dosage and contact time were investigated systematically. ANN-GA and RSM techniques were used to identify the optimal process variables that result in the highest removal. Based on the RSM approach, the optimization conditions for maximum removal efficiency is obtained at pH = 3, adsorbent dosage = 4 g/L, contact time = 30 min, and initial pesticide concentration = 6.2 mg/L. To accurately identify the parameters of nonlinear isotherm and kinetic models, a hybrid evolutionary differential evolution optimization (DEO) is applied. Results indicated that the equilibrium adsorption data were best fitted with Langmuir and Temkin isotherms and kinetic data were well described by pseudo-first and second-order kinetic models. The thermodynamic parameters such as entropy, enthalpy and Gibbs energy were evaluated to study the effect of temperature on pesticide adsorption.

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Efficient Removal of Toxic mMetal Ions (Pb(II) and Hg(II) Ions in Single Component Systems by Adsorption on Romanian Clay Material

Revista de Chimie ◽

10.37358/rc.20.7.8223 ◽

2020 ◽

Vol 71 (7) ◽

pp. 37-47 ◽

Cited By ~ 2

Author(s):

Bianca Azamfire ◽

Dumitru Bulgariu ◽

Laura Bulgariu

Keyword(s):

Experimental Data ◽

Aqueous Solution ◽

Metal Ions ◽

Contact Time ◽

Metal Ion ◽

Clay Material ◽

Order Kinetic ◽

Efficient Removal ◽

Adsorbent Dosage ◽

Short Contact Time

In this study, a local natural clay material was used for the efficient removal of Pb(II)ions and Hg(II) ions from aqueous media, in batch system. The adsorptive potential of clay material was testes at different initial solution pH, adsorbent dosage, contact time and initial heavy metal ions concentration and room temperature (20  2C). The highest adsorption efficiency of clay material was found at initial pH of 7.0 in case of Pb(II) ions, and 2.0 in case of Hg(II) ions, while the adsorbent dosage had the same value (4 g/L) for both metal ions. The adsorption equilibrium is very fast and was reach within 10 min. The modelling of experimental data showed that the adsorption processes followed the Freundlich isotherm model and pseudo-second order kinetic model. Detailed analysis of the experimental data indicate that the retention of Pb(II) and Hg(II) ions from aqueous solution on clay materials involves two processes, one of adsorption and the other of precipitation, whose succession depends on the speciation form of the metal ion in aqueous solution. However, the high adsorption capacity and short contact time are important characteristics which suggest the potential use of this clay material in environmental remediation processes.

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Multi-Component Adsorption of Benzene, Toluene, Ethylbenzene, and Xylene from Aqueous Solutions by Montmorillonite Modified with Tetradecyl Trimethyl Ammonium Bromide

Journal of Chemistry ◽

10.1155/2013/589354 ◽

2013 ◽

Vol 2013 ◽

pp. 1-10 ◽

Cited By ~ 15

Author(s):

H. Nourmoradi ◽

Mehdi Khiadani ◽

M. Nikaeen

Keyword(s):

Experimental Data ◽

Aqueous Solutions ◽

Structural Changes ◽

Freundlich Isotherm ◽

Isotherm Models ◽

Ammonium Bromide ◽

Order Kinetic ◽

Multicomponent Adsorption ◽

Benzene Toluene ◽

Kinetic And Isotherm Models

Multicomponent adsorption of benzene, toluene, ethylbenzene, and xylene (BTEX) was assessed in aqueous solutions by montmorillonite modified with tetradecyl trimethyl ammonium bromide (TTAB-Mt). Batch experiments were conducted to determine the influences of parameters including loading rates of surfactant, contact time, pH, adsorbate concentration, and temperature on the adsorption efficiency. Scanning electron microscope (SEM) and X-ray diffractometer (XRD) were used to determine the adsorbent properties. Results showed that the modification of the adsorbent via the surfactant causes structural changes of the adsorbent. It was found that the optimum adsorption condition achieves with the surfactant loading rate of 200% of the cation exchange capacity (CEC) of the adsorbent for a period of 24 h. The sorption of BTEX by TTAB-Mt was in the order ofB<T<E<X. The experimental data were fitted by many kinetic and isotherm models. The results also showed that the pseudo-second-order kinetic model and Freundlich isotherm model could, respectively, be fitted to the experimental data better than other available kinetic and isotherm models. The thermodynamic study indicated that the sorption of BTEX with TTAB-Mt was achieved spontaneously and the adsorption process was endothermic as well as physical in nature. The regeneration results of the adsorbent also showed that the adsorption capacity of adsorbent after one use was 51% to 70% of original TTAB-Mt.

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Cationic Surfactant-modified Clay as an Adsorbent for the Removal of Synthetic Dyes from Aqueous Solutions

International Journal of Chemical Reactor Engineering ◽

10.1515/ijcre-2017-0064 ◽

2018 ◽

Vol 16 (5) ◽

Cited By ~ 9

Author(s):

Hamed Biglari ◽

Susana RodríguezíCouto ◽

Yusef Omidi Khaniabadi ◽

Heshmatollah Nourmoradi ◽

Mohammad Khoshgoftar ◽

...

Keyword(s):

Aqueous Solutions ◽

Loading Rate ◽

Aqueous Media ◽

Bromocresol Green ◽

Ammonium Bromide ◽

Synthetic Dyes ◽

Order Kinetic ◽

Alizarin Red ◽

Adsorbent Dosage ◽

Isotherm Equation

AbstractIn this study, the potential of hexadecyl trimethyl ammonium bromide modified montmorillonite (HDTMA-Mt) to remove the synthetic dyes Alizarin Red S (ARS) and Bromocresol Green (BCG) from aqueous media was assessed. The effect of different factors including surfactant loading rate onto the clay, contact time, pH, adsorbent dosage and dye concentrations, on the removal of ARS and BCG in batch systems were investigated. The adsorbent was characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray diffractometry (XRD). The equilibrium time for ARS and BCG was reached at 40 and 20 min, respectively, under optimized conditions (i.e. pH = 3, adsorbent dosage=1 g/L, surfactant loading rate onto the clay 70% of the cation exchange capacity (CEC) for ARS and 120% of the CEC for BCG, ARS concentration 50 mg/L and BCG concentration 500 mg/L). The adsorption rate of both dyes fitted the pseudo-second-order kinetic model and the equilibrium data was described by the Freundlich isotherm equation. The maximum monolayer adsorption capacities were equal to 666.6 and 1250 mg/g for ARS and BCG, respectively. Therefore, the HDTMA-Mt can be considered as an effective adsorbent for the removal of ARS and BCG from aqueous solutions.

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Extraction of Heavy Metals from Aqueous Medium by Husk Biomass: Adsorption Isotherm, Kinetic and Thermodynamic study

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2018-1182 ◽

2019 ◽

Vol 233 (2) ◽

pp. 201-223 ◽

Cited By ~ 8

Author(s):

Khalida Naseem ◽

Rahila Huma ◽

Aiman Shahbaz ◽

Jawaria Jamal ◽

Muhammad Zia Ur Rehman ◽

...

Keyword(s):

Metal Ions ◽

Aqueous Medium ◽

Contact Time ◽

Metal Ion ◽

Adsorption Process ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Adsorbent Dosage ◽

Adsorption Sites ◽

Order Kinetic Model

Abstract This study describes the adsorption of Cu (II), Co (II) and Ni (II) ions from wastewater on Vigna radiata husk biomass. The ability of adsorbent to capture the metal ions has been found to be in the order of Ni (II)>Co (II) and Cu (II) depending upon the size and nature of metal ions to be adsorbed. It has been observed that percentage removal of Cu (II), Co (II) and Ni (II) ions increases with increase of adsorbent dosage, contact time and pH of the medium but up to a certain extent. Maximum adsorption capacity (qmax) for Cu (II), Co (II) and Ni (II) ions has been found to be 11.05, 15.04 and 19.88 mg/g, respectively, under optimum conditions of adsorbent dosage, contact time and pH of the medium. Langmuir model best fits the adsorption process with R2 value approaches to unity for all metal ions as compared to other models because adsorption sites are seemed to be equivalent and only monolayer adsorption may occur as a result of binding of metal ion with a functional moiety of adsorbent. Pseudo second order kinetic model best interprets the adsorption process of Cu (II), Co (II) and Ni (II) ions. Thermodynamic parameters such as negative value of Gibbs energy (∆G°) gives information about feasibility and spontaneity of the process. Adsorption process was found to be endothermic for Cu (II) ions while exothermic for Co (II) and Ni (II) ions as signified by the value of enthalpy change (∆H°). Husk biomass was recycled three times for removal of Ni (II) from aqueous medium to investigate its recoverability and reusability. Moreover V. radiata husk biomass has a potential to extract Cu (II) and Ni (II) from electroplating wastewater to overcome the industrial waste water pollution.

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Adsorption of Pb(II) from Aqueous Solutions on Dithizone-Immobilized Coal Fly Ash

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.840.57 ◽

2020 ◽

Vol 840 ◽

pp. 57-63

Author(s):

Dina Fitriana ◽

Mudasir Mudasir ◽

Dwi Siswanta

Keyword(s):

Fly Ash ◽

Adsorption Isotherm ◽

Contact Time ◽

Coal Fly Ash ◽

Order Kinetic ◽

Adsorbent Dosage ◽

Activated Coal ◽

Concentration Of Ions ◽

Order Kinetic Model ◽

Pseudo Second Order

Adsorption of Pb(II) ions onto selective adsorbent of dithizone-immobilized coal fly ash (DCFA) from Holcim, Cilacap, Indonesia has been investigated in batch experiments. Prepared coal fly ash (CFA) modified by immobilization of dithizone previously were characterized by FT-IR and XRD. Several parameters influencing the adsorption of Pb(II) ions such as effect of pH, adsorbent dosage, contact time and initial concentration of ions on the efficiency of the adsorption were studied. The optimum condition of Pb(II) adsorption was found at pH 5, adsorbent dosage 0.1 g, contact time 60 min and initial Pb(II) ions concentration of 60 mg L–1. The adsorption kinetics of Pb(II) ions on DCFA was found to follow a pseudo-second-order kinetic model. The adsorption isotherm data were fitted to the Langmuir model. Kinetics and adsorption isotherm studies suggest that the capacity and affinity of the DCFA in adsorbing Pb(II) ions is significantly improved compared to those of non-immobilized activated coal fly ash (ACFA).

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Adsorption of Nickel and Chromium From Aqueous Solutions Using Copper Oxide Nanoparticles: Adsorption Isotherms, Kinetic Modeling, and Thermodynamic Studies

Avicenna Journal of Environmental Health Engineering ◽

10.34172/ajehe.2019.09 ◽

2019 ◽

Vol 6 (2) ◽

pp. 66-74 ◽

Cited By ~ 3

Author(s):

Raziyeh Hosseini ◽

Mohammad Hossein Sayadi ◽

Hossein Shekari

Keyword(s):

Aqueous Solutions ◽

Copper Oxide ◽

Removal Efficiency ◽

Contact Time ◽

Removal Rate ◽

Copper Oxide Nanoparticles ◽

Isotherm Models ◽

Oxide Nanoparticles ◽

Initial Concentration ◽

Adsorbent Dosage

The research was conducted with an aim to assess the efficiency of copper oxide nanoparticles as an adsorbent to remove Ni and Cr. The effect of pH, adsorbent dosage, contact time, initial concentration of metals (Ni and Cr) on the adsorption rate was evaluated and removal of these elements from aqueous solutions was measured using Atomic Absorption Spectrum System (Conter AA700). Moreover, the kinetic and isotherm besides thermodynamic adsorption models were assessed. The highest Ni and Cr removal rate occurred at an optimal pH of 7, and an initial concentration of 30 mg/L, a time period of 30 minutes, and 1 g/L of copper oxide nanoparticles. In fact, with the increase of adsorbent dosage and contact time, the removal efficiency increased and with initial concentration increase of Ni and Cr ions, the removal efficiency reduced. The correlation coefficient of isotherm models viz. Langmuir, Freundlich, Temkin, Redlich-Peterson, and Koble-Corrigan showed that Ni and Cr adsorption via copper oxide nanoparticles better follows the Langmuir model in relation to other models. The results showed that kinetic adsorption of Ni and Cr via copper oxide nanoparticles follows the second order pseudo model with correlation coefficients above 0.99. In addition, the achieved thermodynamic constants revealed that the adsorption process of metals (i.e., Ni and Cr) via copper oxide nanoparticles was endothermic and spontaneous and the reaction enthalpy values for these metals were 17.727 and 11.862 kJ/mol, respectively. In conclusion, copper oxide nanoparticles can be used as effective and environmentally compatible adsorbents to remove Ni and Cr ions from the aqueous solutions

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