Nano-Mg/Al hydrotalcite: Physicochemical Characterization and Removal of As(III) from Aqueous solutions

2014 ◽  
Vol 1616 ◽  
Author(s):  
E. Ramos-Ramírez ◽  
N. L. Gutiérrez-Ortega ◽  
G. Rangel-Porras ◽  
G. Herrera-Pérez
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Natural Waters ◽  
Arsenic Removal ◽  
Sol Gel ◽  
Physicochemical Characterization ◽  
Chemical Characterization ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Ionic Exchange

ABSTRACTArsenic is one of the most toxic elements that can be found. Arsenic is mainly emitted by the copper, lead and zinc production, in agriculture as pesticides and herbicides. Two forms of arsenic are common in natural waters: arsenite (AsO33−) and arseniate (AsO43−), referred to as As(III) and As(V). The nano-Mg/Al-hydrotalcites present ionic exchange and adsorbent capacities. In this work, the physic-chemical characterization of nano-Mg/Al-hydrotalcites and his arsenic removal capacityis described. The solids were synthesized by the sol-gel method with Mg/Al=2 and 3 ratio. The solids and their thermal treated products were characterized by XRD, FTIR, DTA, TGA and N2 adsorption. The solids were used as adsorbents As(III) in aqueous solutions. Adsorption isotherm studies of As(III) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin–Radushkevich adsorption isotherm models. The As(III) adsorption isotherm data fit best to the isotherm Freundlich model. The maximum As(III) uptake capacity by nano-Mg/Al-hydrotalcites and the heated solids were determined using the Freundlich equation and were found to 547.46, 660.15, 799.88 and 739.12 mg As(III)/g HT-Mg/Al=2, HT-Mg/Al=3, HT-Mg/Al=2 at 350°C and HT-Mg/Al=3 at 350°C respectively. In the kinetic studies using 40 mg/L concentration of As(III) solutions was obtained an excellent removal capacity in contact times less at one minute.

scholarly journals Optimization, equilibrium and kinetic studies of Zn2+ and Ni2+ adsorption from aqueous solutions using composite adsorbent

2018 ◽  
Vol 67 (3) ◽  
pp. 279-290 ◽  
Author(s):  
Haider M. Zwain ◽  
Mohammadtaghi Vakili ◽  
Irvan Dahlan
Keyword(s):  
Contact Time ◽  
Coal Fly Ash ◽  
Sol Gel ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Experimental Conditions ◽  
Palm Oil Fuel Ash ◽  
Composite Adsorbent ◽  
Oil Fuel

Abstract A novel RHA/PFA/CFA composite adsorbent was synthesized from rice husk ash (RHA), palm oil fuel ash (PFA), and coal fly ash (CFA) by modified sol-gel method. Effect of different parameters such as adsorbent dosage, contact time, and pH were studied using batch experiment to optimize the maximum zinc (Zn2+) and nickel (Ni2) adsorption conditions. Results showed that the maximum adsorption condition occurred at adsorbent amount of 10 g/L, contact time of 60 min, and pH 7. At this condition, the removal efficiencies were 81% and 61% for Zn2+ and Ni2+, in which the adsorption capacities (qmax) were 21.74 mg/g and 17.85 mg/g, respectively. Adsorption behavior of RHA/PFA/CFA composite adsorbent was studied through the various isotherm models at different adsorbent amounts. The results indicated that the Freundlich isotherm model gave an excellent agreement with the experimental conditions. Based on the results obtained from the kinetic studies, pseudo-second-order was suitable for the adsorption of Ni2+ and Zn2+, compared to the pseudo-first-order model. The results presented in this study showed that RHA/PFA/CFA composite adsorbent successfully adsorbed Zn2+ and Ni2.

scholarly journals Synthesis and characterization of modified activated carbon (MgO/AC) for methylene blue adsorption: optimization, equilibrium isotherm and kinetic studies

2021 ◽  
Author(s):  
Vahab Ghalehkhondabi ◽  
Alireza Fazlali ◽  
Keyhan Ketabi
Keyword(s):  
Methylene Blue ◽  
Activated Carbon ◽  
Natural Waters ◽  
Sol Gel ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
Human Beings ◽  
Operational Conditions ◽  
Coating Method

Abstract Methylene blue (MB) is the cationic dye that is widely used for coloring cotton, wool, and silk. Since MB is harmful to human beings and toxic to microorganisms, there is the need to find cheap and efficient methods for removal of MB from wastewater prior to disposal into natural waters. In the present study, MB adsorption potential of MgO/AC prepared using a sol–gel-thermal deep-coating method was compared with the activated carbon (AC). The central composite design (CCD) as a method of the response surface methodology (RSM) was applied to minimize the number of runs and process optimization. The characterization of the microporous MgO/AC composite showed that the magnesium oxide nanoparticles were successfully coated on the AC and the BET specific surface area of AC and MgO/AC were 1,540 and 1,246 m2/g, respectively. The MB removal efficiency and the maximum adsorption capacity of AC and MgO/AC were 89.6, 97.5% and 571.7, 642.3 mg/g, respectively under optimum operational conditions of initial dye concentration of 100.9 mg/L, the adsorbent dosage of 69.4 mg/100 mL, pH of 10.2 and contact time of 149.1 min. According to an analysis of variance (ANOVA), the initial dye concentration and its interaction with the other effective factors have a large impact on adsorption efficiency. Furthermore, the mechanism of adsorption followed the Langmuir isotherm (R2 = 0.9935, Δqe = 2.9%) and adsorption kinetics fitted by the pseudo-second-order model (R2 = 0.9967, Δqe = 6.6%). Finally, our results suggest that the prepared MgO/AC is an efficient and promising material for dye wastewater treatment.

scholarly journals Arsenic Removal from Aqueous Solutions Using Carbon Embedded Silica and Zeolite: Column Adsorption Studies

2020 ◽  
pp. 42-53
Keyword(s):  
Aqueous Solutions ◽  
Rice Husk ◽  
Arsenic Removal ◽  
Freundlich Isotherm ◽  
Column Height ◽  
Isotherm Models ◽  
Tem Analysis ◽  
X Ray ◽  
Transmission Electron ◽  
Column Adsorption

Column adsorption of the As (III) & As (V) using rice husk mediated carbon embedded silica (CES) and zeolite (Z-RHA) has been proved promising technique rather than the other conventional methods. The present work investigates the adsorption capability of newly manufactured CES and Z-RHA to remove As (III) & As (V) from aqueous solutions. Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Scanning electron microscope (SEM), Energy dispersive X-ray (EDX), and Transmission electron microscopy (TEM) analysis have been investigated for the characterization of synthesized materials. The effects of different parameters like initial concentrations, column diameter, column height, particle size distribution have been investigated. The maximum removal efficiency of CES adsorbents for As (III) is 98% and for As (V) is 85%, and of Z-RHA for As (III) is 95% and for As (V) is 92%. To describe the adsorption behavior the Langmuir and Freundlich isotherm models as well as to kinetics models like Adam-Bohart, Thomas, and Yoon Nelson model were applied. Finally, to dispose of the rice husk mediated adsorbents after arsenic treatment solidification has been done.

scholarly journals Removal of zinc ions as zinc chloride complexes from strongly acidic aqueous solutions by ionic exchange

2014 ◽  
Vol 12 (8) ◽  
pp. 821-828 ◽  
Author(s):  
Emilia Gîlcă ◽  
Andrada Măicăneanu ◽  
Petru Ilea
Keyword(s):  
Kinetic Studies ◽  
Sorption Kinetics ◽  
Exchange Capacity ◽  
Second Order ◽  
Isotherm Models ◽  
Ionic Exchange ◽  
Order Kinetic ◽  
Zinc Ions ◽  
Chloride Complexes ◽  
Pseudo Second Order

AbstractThe aim of this study was to compare several anion exchangers and to investigate the capacity of Amberlite IRA410 to remove zinc as chloride [ZnCl3]− from hydrochloric solutions (1 M). Influence of the process parameters such as stirring rate, resin quantity and zinc initial concentration over the removal process, was considered. The highest experimental ionic exchange capacity between the considered anionic exchangers, in the same working conditions (500 rpm, 5 g resin and 500 mg L−1), was obtained for Amberlite IRA410, 8.34 mg g−1. With an increase of zinc ions concentration, ionic exchange capacity increased up to 19.31 mg g−1 (1100 mg L−1). The experimental data were analysed using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherm models. The results were also analyzed using sorption kinetics models, pseudo-first-, pseudo-second-order, intra-particle and film diffusion models. From the Dubinin-Radushkevich and Temkin isotherm models the mean free energy and heat of sorption were calculated to be 7.45 kJ mol−1, respectively 1×10−4 kJ mol−1, which indicates that zinc sorption is characterized by a physisorption process. Kinetic studies showed that the adsorption followed a pseudo-second-order kinetic model.

Arsenic Removal via Cellulose-Based Organic/Inorganic Hybrid Materials from Drinking Water

2012 ◽  
Vol 730-732 ◽  
pp. 563-568
Author(s):  
Catarina Martins ◽  
Rui F. Duarte ◽  
Maria C.F. Magalhães ◽  
Dmitry Evtuguin
Keyword(s):  
Aqueous Solutions ◽  
Hybrid Materials ◽  
Arsenic Removal ◽  
Sol Gel ◽  
Arsenic Concentration ◽  
Cellulose Fiber ◽  
Silica Network ◽  
Bleached Pulp ◽  
Removal Of Arsenic

Cellulose/silica derived hybrids materials (CSH), functionalized with aluminium, calcium, and propylammonium ions, were tested for their possible use in the removal of arsenic from aqueous solutions with controlled compositions to levels lower than 10 μg As/L. CSH were synthesized by sol-gel method using bleached pulp, as source of cellulose fiber, and tetraethoxysilane (TEOS) as main silica precursor. The silica network, made in situ, contained various anchored cations such as propylammonium (CSH-PA), aluminium (CSH-Al) and, calcium (CSH-Ca). Thin films or mesoparticles of silica were deposited on cellulose fibers as shown by SEM and XRD. These hybrid materials were immersed in controlled ionic strength aqueous solutions with arsenic concentrations lower than 0.2 mg As/L. The best performance was shown by CSH-PA that was able to remove a maximum of 20 % of the total arsenic concentration.

scholarly journals Adsorption of crystal violet dye onto olive leaves powder: Equilibrium and kinetic studies

2021 ◽  
Author(s):  
CI Chemistry International
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Crystal Violet ◽  
Low Cost ◽  
Wave Length ◽  
Kinetic Studies ◽  
Absorption Spectrometry ◽  
Isotherm Models ◽  
Olive Leaves ◽  
Crystal Violet Dye

Adsorption of crystal violet dye from aqueous solutions applying olive leaves powder (OLP) as a biosorbent has been examined under various experimental circumstances. The influence of contact time, pH, initial concentration of studied dye and adsorbent dose on the adsorption process has been investigated applying batch experiments. The concentration of remaining dye has been determined using molecular absorption spectrometry at wave length of 580 nm. The maximum removal of studied dye has been realized at pH 7.5 with a percent removal of 99.2% after 20 min of agitation time. Langmuir, Freundlich, and Temkin isotherm models exemplify the best fit for the experimental data; while the elevated adsorption capacity was 181.1 mg.g1. Adsorption kinetics of crystal violet was expected sufficiently with the empirical pseudo-second-order model. Corresponding to the adsorption capacity, olive leaves powder thought as a low cost, effective, and environmentally friendly biosorbent for the removal of crystal violet dye from aqueous solutions.

scholarly journals Removal of Carcinogenic Dyes Congo red (CR) and Bismarck brown Y (BBY) by Adsorption onto Reusable Hydrogels Derived from Acrylamide

2021 ◽  
Vol 2063 (1) ◽  
pp. 012011
Author(s):  
Huda S Al-Niaeem ◽  
Ali A Abdulwahid ◽  
Whidad S Hanoosh
Keyword(s):  
Experimental Data ◽  
Aqueous Solutions ◽  
Congo Red ◽  
Freundlich Isotherm ◽  
Kinetic Studies ◽  
Sulphonic Acid ◽  
Isotherm Models ◽  
Anionic Dyes ◽  
Best Fitting ◽  
Pseudo Second Order

Abstract Hydrogels of acrylamide (AM), acrylamide\ 2-acrylamido-2-methyl-1-propane sulphonic acid (AMS), and acrylamide\ 2-acrylamido-2-methyl-1-propane sulphonic acid\graphene oxide (AMSGO) were prepared as adsorbents to remove carcinogenic dyes Congo red (CR) and Bismarck brown Y (BBY) from aqueous solutions. Hydrogels were characterized using FSEM and XRD analyses. For both dyes, the synthesized hydrogels demonstrated high adsorption capability at near-neutral pH. Experimental adsorption data were analyzed using the Langmuir and Freundlich isotherm models. It was found that the Langmuir model was more suitable for the experimental data. Kinetic studies found that the pseudo-second-order model demonstrated the best fitting to the experimental data. In addition, thermodynamic studies suggest that the adsorption process was spontaneous and endothermic. The prepared hydrogels were regenerated and reused in four consecutive cycles and it could be applied to remove anionic dyes from aqueous solutions as an effective adsorbent.

scholarly journals Removal of Zinc from Aqueous Solutions by Magnetite Silica Core-Shell Nanoparticles

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Masoomeh Emadi ◽  
Esmaeil Shams ◽  
Mohammad Kazem Amini
Keyword(s):  
Aqueous Solutions ◽  
Sol Gel ◽  
Freundlich Isotherm ◽  
Second Order ◽  
Isotherm Models ◽  
Core Shell ◽  
Order Kinetic ◽  
Shell Nanoparticles ◽  
Silica Core ◽  
Core Shell Nanoparticles

Magnetite silica core-shell nanoparticles (Fe3O4-SiO2) were synthesized and evaluated as a nanoadsorbent for removing Zn(II) from aqueous solutions. The core-shell nanoparticles were prepared by combining coprecipitation and sol-gel methods. Nanoparticles were characterized by X-ray diffraction, transmission electron microscopy (TEM), and FT-IR. The magnetization values of nanoparticles were measured with vibrating sample magnetometer (VSM). The adsorption of Zn(II) ions was examined by batch equilibrium technique. The effects of pH, initial Zn(II) concentration, and contact time on the efficiency of Zn(II) removal were studied. The equilibrium data, analyzed by using Langmuir and Freundlich isotherm models, showed better agreement with the former model. Using the Langmuir isotherm model, maximum capacity of the nanoadsorbent for Zn(II) was found to be 119 mg g−1at room temperature. Kinetic studies were conducted and the resulting data were analyzed using first- and second-order equations; pseudo-second-order kinetic equation was found to provide the best correlation. The adsorption and sedimentation times were very low. The nanoadsorbent can be easily separated from aqueous solution by a magnet. Repeated adsorption acid regeneration cycles were performed to examine the stability and reusability of the nanoadsorbent. The result of this study proved high stability and reusability of Fe3O4-SiO2as an adsorbent for Zn(II) ions.

scholarly journals Exploring Adsorption Process of Lead (II) and Chromium (VI) Ions from Aqueous Solutions on Acid Activated Carbon Prepared from Juniperus procera Leaves

Processes ◽  
2019 ◽  
Vol 7 (4) ◽  
pp. 217 ◽  
Author(s):  
Ismat H. Ali ◽  
Mohammed K. Al Mesfer ◽  
Mohammad I. Khan ◽  
Mohd Danish ◽  
Majed M. Alghamdi
Keyword(s):  
Activated Carbon ◽  
Aqueous Solutions ◽  
Kinetic Studies ◽  
Ion Concentration ◽  
Isotherm Models ◽  
Solution Ph ◽  
Chromium Vi ◽  
Biosorption Process ◽  
Endothermic Process ◽  
Juniperus Procera

The adsorption potential of acid activated carbon prepared from leaves of Juniperus procera to remove Pb(II) and Cr(VI) toxic ions from aqueous solutions was investigated. The effects of solution pH, adsorbent mass, contact time, initial ion concentration and temperature on the biosorption process were studied, and the optimum conditions were determined. Moreover, Langmuir, Freundlich, Temkin and Dubinin–Radushkevich adsorption isotherm models were applied to analyze adsorption data. Thermodynamic parameters for the adsorption processes were calculated. Adsorption was found to be a spontaneous and endothermic process. In addition, kinetic studies revealed a pseudo-first order kinetics biosorption process. The obtained results suggest that acid activated Juniperus procera leaves powder can be used as a cheap, efficient and environmentally friendly adsorbent material with high removal efficiency up to 98% for Pb(II) and 96% for Cr(VI) at 0.80 and 1.00 g/100 mL, respectively. The duration of the process was 100 min and 120 min for Pb(II) and Cr(VI) ions, respectively. The morphology of the of prepared activated carbon was investigated by scanning electron microscope (SEM).

scholarly journals Arsenic Removal from Aqueous Solutions bySalvadora persicaStem Ash

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Ferdos Kord Mostafapour ◽  
Edris Bazrafshan ◽  
Mahdi Farzadkia ◽  
Samira Amini
Keyword(s):  
Aqueous Solutions ◽  
Contact Time ◽  
Arsenic Removal ◽  
Arsenic Concentration ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Aqueous Environment ◽  
Salvadora Persica ◽  
Naturally Occurring ◽  
Maximum Removal

Arsenic is a naturally occurring metalloid, which is widely distributed in nature and is regarded as the largest mass poisoning in history. In the present study, the adsorption potential ofSalvadora persica(S. persica) stem ash in a batch system for the removal of As(V) from aqueous solutions was investigated. Isotherm studies were carried out to evaluate the effect of contact time (20–240 min), pH (2–11), initial arsenic concentration (50–500 μg/L), and adsorbent dose on sorption efficiency. Maximum removal efficiency of 98.33% and 99.32% was obtained at pH 6, adsorbent dosage 3.5 g/L, initial As(V) concentration 500 μg/L, and contact time 80 and 60 min forS. persicastem ash at 300 °C and 500 °C, respectively. Also, the adsorption equilibriums were analyzed by the Langmuir and Freundlich isotherm models. Such equilibriums showed that the adsorption data was well fitted with the Freundlich isotherm model forS. persicastem ash at both 300 °C and 500 °C (R2=0.8983and 0.9274, resp.). According to achieved results, it was defined thatS. persicastem ash can be used effectively for As(V) removal from the aqueous environment.

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