scholarly journals Comparison of Cr(VI) Adsorption Using Synthetic Schwertmannite Obtained by Fe3+ Hydrolysis and Fe2+ Oxidation: Kinetics, Isotherms and Adsorption Mechanism

2021 ◽  
Vol 22 (15) ◽  
pp. 8175
Author(s):  
Justyna Ulatowska ◽  
Łukasz Stala ◽  
Izabela Polowczyk
Keyword(s):  
Adsorption Mechanism ◽  
Distribution Density ◽  
Second Order ◽  
Process Conditions ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Before And After ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Isotherm And Kinetic Models

Good sorption properties and simple synthesis route make schwertmannite an increasingly popular adsorbent. In this work, the adsorption properties of synthetic schwertmannite towards Cr(VI) were investigated. This study aimed to compare the properties and sorption performance of adsorbents obtained by two methods: Fe3+ hydrolysis (SCHA) and Fe2+ oxidation (SCHB). To characterise the sorbents before and after Cr(VI) adsorption, specific surface area, particle size distribution, density, and zeta potential were determined. Additionally, optical micrographs, SEM, and FTIR analyses were performed. Adsorption experiments were performed in varying process conditions: pH, adsorbent dosage, contact time, and initial concentration. Adsorption isotherms were fitted by Freundlich, Langmuir, and Temkin models. Pseudo-first-order, pseudo-second-order, intraparticle diffusion, and liquid film diffusion models were used to fit the kinetics data. Linear regression was used to estimate the parameters of isotherm and kinetic models. The maximum adsorption capacity resulting from the fitted Langmuir isotherm is 42.97 and 17.54 mg·g−1 for SCHA and SCHB. Results show that the adsorption kinetics follows the pseudo-second-order kinetic model. Both iron-based adsorbents are suitable for removing Cr(VI) ions from aqueous solutions. Characterisation of the adsorbents after adsorption suggests that Cr(VI) adsorption can be mainly attributed to ion exchange with SO42− groups.

scholarly journals KINETIC AND ISOTHERM STUDY OF CUPPER ADSORPTION FROM AQUEOUS SOLUTION USING WASTE EGGSHELL

2014 ◽  
Vol 22 (2) ◽  
pp. 132-140 ◽  
Author(s):  
Ayben Polat ◽  
Sukru Aslan
Keyword(s):  
Ph Value ◽  
Experimental System ◽  
Second Order ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Isotherm Study ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

The sorption of Cu2+ ions from aqueous solutions by eggshell was investigated in a batch experimental system with respect to the temperature, initial Cu2+ concentrations, pH, and biosorbent doses. The adsorption equilibrium was well described by the Langmuir isotherm model with the maximum adsorption capacity of 5.05 mg Cu2+/g eggshell at 25 °C. The value of qe increased with increasing the temperature while also increases the release of Ca2+ and HCO−3 ions from the eggshell. The highest sorption of Cu onto the waste eggshell was determined at the initial pH value of 4.0. The results confirming that the adsorption reaction of Cu2+ on the eggshell was thought to be endothermic. A comparison of the kinetic models such as pseudo first and second-order kinetics, intraparticle diffusion, and Elovich on the sorption rate demonstrated that the system was best described by the pseudo second-order kinetic model.

scholarly journals Performance of Immobilized Chlorella Algae for Removing pb(II) Ions from Aqueous Solution

2019 ◽  
Vol 20 (3) ◽  
pp. 1-6
Author(s):  
Hala N. Abdulkareem ◽  
Abeer I. Alwared
Keyword(s):  
Second Order ◽  
Polluted Water ◽  
Order Kinetic ◽  
Operational Parameters ◽  
Algae Biomass ◽  
Adsorbent Surface ◽  
Before And After ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Chlorella Algae

This study aims to show the  effectiveness of immobilization of Chlorella green algae biomass in the form of bead for the removal of lead ions from synthetic polluted water  at various operational parameters such as pH (2–6), biosorbent dosage (0.5–20 g/L) and initial concentration (10–100 mg/L). More than 90 % removal efficiency was achieved. FTIR and SEM-EDX analysis of the biosorbent before and after sorption show differences in the functional groups on the adsorbent surface. Langmuir and Freundlich equilibrium isotherm, pseudo-first-order and pseudo-second-order kinetic models were applied to the experimental and results and show good conformity with Langmuir isotherm model and pseudo-second-order kinetic model with correlation coefficient (0.994) and (0.998) respectively.

scholarly journals Removal of Pb(II) using Hydroxyapatite from Golden Snail Shell (Pomacea canaliculata L.) Modified with Silica

Molekul ◽  
2020 ◽  
Vol 15 (2) ◽  
pp. 130
Author(s):  
Poedji Loekitowati Hariani ◽  
Fahma Riyanti ◽  
Fatma Fatma ◽  
Addy Rachmat ◽  
Aldi Herbanu
Keyword(s):  
Contact Time ◽  
Second Order ◽  
Pomacea Canaliculata ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Adsorption Parameters ◽  
First Order ◽  
Optimum Ph ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The composites of hydroxyapatite and SiO2 were successfully synthesized. The hydroxyapatite was prepared from golden snail shells (Pomacea canaliculata L). The hydroxyapatite and hydroxyapatite-SiO2 composites were characterized using XRD, FTIR, SEM-EDS. Furthermore, hydroxyapatite and hydroxyapatite-SiO2 composites were used to remove Pb(II) from aqueous solution. Various adsorption parameters such as pH of the solution, contact time, and initial Pb(II) concentration were used to study the adsorption process. The optimum pH of the solution for removal of Pb(II) by hydroxyapatite and hydroxyapatite-SiO2 composite at pH 6 and contact time at 60 minutes. Both adsorbents follow the Langmuir isotherm. The maximum adsorption capacity of the hydroxyapatite-SiO2 composite is greater compare to hydroxyapatite, respectively 135.14 and 123.46 mg/g. The pseudo-second order kinetic model had a correlation coefficient (R2) greater than the pseudo-first order so pseudo-second order kinetic is better to describe adsorption kinetics

scholarly journals Adsorption Kinetics for the Removal of Hazardous Dye Congo Red by Biowaste Materials as Adsorbents

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Sumanjit Kaur ◽  
Seema Rani ◽  
Rakesh Kumar Mahajan
Keyword(s):  
Congo Red ◽  
Low Cost ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Experimental Conditions ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The present work aims to investigate the removal of dye congo red from aqueous solutions by two low-cost biowaste adsorbents such as ground nut shells charcoal (GNC) and eichhornia charcoal (EC) under various experimental conditions. The effect of contact time, ionic strength, temperature, pH, dye concentration, and adsorbent dose on the removal of dye was studied. The kinetic experimental data were fitted to pseudo-first order, pseudo-second order, intraparticle diffusion, Elovich model, and Bangham’s model. Results imply that adsorption of congo red on these adsorbents nicely followed the second order kinetic model and maximum adsorption capacity was found to be 117.6 and 56.8 mg g−1for GNC and EC at 318 K, however it increases with increase in temperature for both adsorbents. Equilibrium isotherms were analyzed by Langmuir, Freundlich, Temkin, Dubinin and Radushkevich, and Generalized Isotherms. Freundlich isotherm described the isotherm data with high-correlation coefficients. The results of the present study substantiate that biowaste material GNC and EC are promising adsorbents for the removal of the dye congo red.

scholarly journals Magnetic alginate beads with high basic dye removal potential and excellent regeneration ability

2017 ◽  
Vol 95 (8) ◽  
pp. 807-815 ◽  
Author(s):  
K.Z. Elwakeel ◽  
A.A. El-Bindary ◽  
A.Z. El-Sonbati ◽  
A.R. Hawas
Keyword(s):  
Langmuir Isotherm ◽  
Alginate Beads ◽  
Second Order ◽  
Regeneration Ability ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Isotherm Equation ◽  
Langmuir Isotherm Equation ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The adsorption of crystal violet (CV) dye onto magnetic alginate (MAlg) composite from aqueous solutions was studied. Experiments were carried out as function of contact time, dosage, temperature, pH, and CV concentration in the solutions. Optimum CV uptake was observed at equilibrium pH 7 and most of the CV was sorbed within 30 min. The equilibrium adsorption data were analyzed using two common adsorption models: Langmuir and Freundlich. The results revealed that Langmuir isotherm fit the experimental results well. The maximum adsorption capacity obtained from Langmuir isotherm equation was 0.113 mmol g−1 at 298 ± 1 K. The kinetics adsorption of CV onto MAlg composite was investigated using the pseudo first-order and pseudo second-order kinetic models. The results showed that the adsorption of CV onto MAlg composite followed pseudo second-order kinetic model. Thermodynamic data indicated that the adsorption process is an endothermic and spontaneous reaction. Due to its outstanding adsorption capacities, MAlg composite is an excellent adsorbent for the removal of CV. The composite regeneration was greater than 98.6% with 0.01 mol/L HCl, and MAlg composite could be repeatedly utilized for CV removal with negligible loss in sorption capacity.

scholarly journals Sawdust for the Removal of Heavy Metals from Water: A Review

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4318
Author(s):  
Elie Meez ◽  
Abbas Rahdar ◽  
George Z. Kyzas
Keyword(s):  
Heavy Metals ◽  
Adsorption Mechanism ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Suitable Material ◽  
Removal Of Heavy Metals ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
And Control ◽  
Environmental Agencies

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.

Studies of Chromium Removal from Tannery Effluents by Dead Streptomyces Rimosus

2008 ◽  
Vol 3 (1) ◽  
Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar
Keyword(s):  
Fractional Power ◽  
Kinetic Studies ◽  
Second Order ◽  
Order Kinetic ◽  
Streptomyces Rimosus ◽  
Tannery Effluents ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ph Range

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.

scholarly journals Insights into Starch Coated Nanozero Valent Iron-Graphene Composite for Cr(VI) Removal from Aqueous Medium

2016 ◽  
Vol 2016 ◽  
pp. 1-10 ◽  
Author(s):  
Prasanna Kumarathilaka ◽  
Vimukthi Jayaweera ◽  
Hasintha Wijesekara ◽  
I. R. M. Kottegoda ◽  
S. R. D. Rosa ◽  
...  
Keyword(s):  
Point Of Zero Charge ◽  
Inert Material ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Graphene Composite ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
First Time

Embedding nanoparticles into an inert material like graphene is a viable option since hybrid materials are more capable than those based on pure nanoparticulates for the removal of toxic pollutants. This study reports for the first time on Cr(VI) removal capacity of novel starch stabilized nanozero valent iron-graphene composite (NZVI-Gn) under different pHs, contact time, and initial concentrations. Starch coated NZVI-Gn composite was developed through borohydrate reduction method. The structure and surface of the composite were characterized by scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer-Emmett-Teller (BET), and point of zero charge (pHpzc). The surface area and pHpzc of NZVI-Gn composite were reported as 525 m2 g−1 and 8.5, respectively. Highest Cr(VI) removal was achieved at pH 3, whereas 67.3% was removed within first few minutes and reached its equilibrium within 20 min obeying pseudo-second-order kinetic model, suggesting chemisorption as the rate limiting process. The partitioning of Cr(VI) at equilibrium is perfectly matched with Langmuir isotherm and maximum adsorption capacity of the NZVI-Gn composite is 143.28 mg g−1. Overall, these findings indicated that NZVI-Gn composite could be utilized as an efficient and magnetically separable adsorbent for removal of Cr(VI).

Kinetics of lead ion biosorption from aqueous solution onto lyophilized Aspergillus niveus

2010 ◽  
Vol 5 (1) ◽  
Author(s):  
Hülya Karaca ◽  
Turgay Tay ◽  
Merih Kıvanç
Keyword(s):  
Adsorption Capacity ◽  
Correlation Coefficients ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Lead Ions ◽  
Lead Ion ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Aspergillus Niveus ◽  
Pseudo Second Order

The biosorption of lead ions (Pb2+) onto lyophilized fungus Aspergillus niveus was investigated in aqueous solutions in a batch system with respect to pH, contact time and initial concentration of the ions at 30 °C. The maximum adsorption capacity of lyophilized A. niveus was found to be 92.6 mg g−1 at pH 5.1 and the biosorption equilibrium was established about in 30 min. The adsorption capacity obtained is one of the highest value among those reported in the literature. The kinetic data were analyzed using the pseudo-first-order kinetic, pseudo-second-order kinetic, and intraparticle diffusion equations. Kinetic parameters, such as rate constants, equilibrium adsorption capacities, and related correlation coefficients for the kinetic models were calculated and discussed. It was found that the adsorption of lead ions onto lyophilized A. niveus biomass fit the pseudo-second-order kinetic model well. The Langmuir and Freundlich isotherm parameters for the lead ion adsorption were applied and the Langmuir model agreed better with the adsorption of lead ions onto lyophilized A. niveus.

scholarly journals Efficient Congo Red Removal Using Porous Cellulose/Gelatin/Sepiolite Gel Beads: Assembly, Characterization, and Adsorption Mechanism

Polymers ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3890
Author(s):  
Chenlu Jiao ◽  
Die Liu ◽  
Nana Wei ◽  
Jiannan Gao ◽  
Fan Fu ◽  
...  
Keyword(s):  
Congo Red ◽  
Adsorption Mechanism ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Dye Wastewater ◽  
Step Method ◽  
Gel Beads ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Highly Porous

Porous sustainable cellulose/gelatin/sepiolite gel beads were fabricated via an efficient ‘hydrophilic assembly–floating droplet’ two-step method to remove Congo red (CR) from wastewater. The beads comprised microcrystalline cellulose and gelatin, forming a dual network framework, and sepiolite, which acted as a functional component to reinforce the network. The as-prepared gel beads were characterized using FTIR, SEM, XRD, and TGA, with the results indicating a highly porous structure that was also thermally stable. A batch adsorption experiment for CR was performed and evaluated as a function of pH, sepiolite addition, contact time, temperature, and initial concentration. The kinetics and isotherm data obtained were in agreement with the pseudo-second-order kinetic model and the Langmuir isotherm, with a maximum monolayer capacity of 279.3 mg·g−1 for CR at 303 K. Moreover, thermodynamic analysis demonstrated the spontaneous and endothermic nature of the dye uptake. Importantly, even when subjected to five regeneration cycles, the gel beads retained 87% of their original adsorption value, suggesting their suitability as an efficient and reusable material for dye wastewater treatments.

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