scholarly journals Cadmium Adsorption on HDTMA Modified Montmorillionite

2009 ◽  
Vol 6 (1) ◽  
pp. 8 ◽  
Author(s):  
Mohd. Elmuntasir I. Ahmed
Keyword(s):  
Exchange Capacity ◽  
Batch Adsorption ◽  
Cadmium Removal ◽  
Surface Precipitation ◽  
Isotherm Equation ◽  
Modified Montmorillonite ◽  
Adsorption Capacities ◽  
Langmuir Isotherm Equation ◽  
High Concentrations ◽  
Monolayer Coverage

In this paper the possibility of cadmium removal from aqueous solutions by adsorption onto modified montmorillonite clay is investigated. Batch adsorption experiments performed revealed an enhanced removal of cadmium using HDTMA modified montmorillonite to 100% of its exchange capacity. Modified montmorillonite adsorption capacity increases at higher pHs suggesting adsorption occurs as a result of surface precipitation and HDTMA complex formation due to the fact that the original negatively charged montmorillonite is now covered by a cationic layer of HDTMA. Adsorption isotherms generated followed a Langmuir isotherm equation possibly indicating a monolayer coverage. Adsorption capacities of up to 49 mg/g and removals greater than 90% were achieved. Anionic selectivity of the HDTMA modified monmorillonite is particularly advantageous in water treatment applications where high concentrations of less adsorbable species are present, and the lack of organoclay affinity for these species may allow the available capacity to be utilized selectively by the targeted species. 

scholarly journals Planting trees and amending with waste increases the capacity of mine tailings soils to retain Ni, Pb and Zn

2014 ◽  
Vol 4 ◽  
Author(s):  
Verónica Asensio Fandiño ◽  
Flora A. Vega ◽  
Rubén Forján ◽  
Emma F. Covelo
Keyword(s):  
Sorption Capacity ◽  
Soil Ph ◽  
Mine Tailings ◽  
Cation Exchange Capacity ◽  
Inorganic Carbon ◽  
Exchange Capacity ◽  
Tree Planting ◽  
Batch Adsorption ◽  
Organic And Inorganic Carbon ◽  
High Concentrations

The sorption capacity for Ni, Pb and Zn of mine tailings soil with and without reclamation treatment (tree planting and waste amendment) was evaluated using the batch adsorption technique. It is important to determine the capacity of waste-amended soils to retain Ni, Pb and Zn, as the sludges used usually have high concentrations of these metals. The results obtained in the present study showed that the untreated mine tailings soil had a low capacity for Ni, Pb and Zn retention. The sorption capacity for Pb increased significantly in all of the treated soils, without any significant differences between them. The treatment that most increased the sorption capacity for Ni and Zn was planting with trees and amending with waste simultaneously, as this increased the concentration of both organic and inorganic carbon, exchangeable calcium, soil pH and effective cation exchange capacity

Preparation and Chelating Properties of Polystyrene Modified Ethoxycarbonyl Thiourea Resin

2011 ◽  
Vol 239-242 ◽  
pp. 781-785 ◽  
Author(s):  
Shuai Wang ◽  
Hong Zhong ◽  
Liu Yin Xia ◽  
Zhong Nan Wang ◽  
Qian Zhang
Keyword(s):  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Maximum Adsorption Capacity ◽  
Polymer Grafting ◽  
Isotherm Equation ◽  
Adsorption Capacities ◽  
Adsorption Data ◽  
Separation Factors ◽  
Langmuir Isotherm Equation ◽  
Freundlich Adsorption Isotherm

A novel polystyrene modified ethoxycarbonyl thiourea resin(PSETU) was synthesized by polymer grafting of aminated polystyrene and ethoxycarbonyl isothiocyanate. The adsorption capacities of PSETU follow the order: Au(III) > Cu(II) > Zn(II) > Ni(II) > Fe(III) > Ca(II) ≈ Mg(II). The adsorption capacity for Au(III) increases with the increase of contact time, temperature and initial concentration of Au(III). The adsorption data fit Boyd’s diffusion equation of liquid film, Langmuir adsorption isotherm and Freundlich adsorption isotherm. The maximum adsorption capacity of PSETU calculated by Langmuir isotherm equation is 3.485 mmol/g, and the separation factors of PSETU for Au(III)-base metal ions are above 380. According to XPS results, the functional atoms of PSETU coordinate with Au(III) during the adsorption process.

scholarly journals A comparative study of the removal of lead, cadmium and zinc ions from aqueous solutions by natural and Fe(III)-modified zeolite

2014 ◽  
Vol 20 (2) ◽  
pp. 283-293 ◽  
Author(s):  
Marija Mihajlovic ◽  
Slavica Lazarevic ◽  
Ivona Jankovic-Castvan ◽  
Bojan Jokic ◽  
Djordje Janackovic ◽  
...  
Keyword(s):  
Natural Zeolite ◽  
Ph Value ◽  
Exchange Capacity ◽  
Ion Concentration ◽  
Point Of Zero Charge ◽  
Batch Adsorption ◽  
Modified Zeolite ◽  
Adsorption Mechanisms ◽  
Adsorption Capacities ◽  
Zero Charge

The main purpose of this research was to explain the differences in the adsorption mechanisms and adsorption capacities of natural and Fe(III)-modified zeolite for Pb2+, Zn2+ and Cd2+ ions. The adsorbents were characterized with respect to their phase composition, morphology, specific surface area, cation exchange capacity and point of zero charge. Batch adsorption experiments were performed as a function of the initial ion concentration and temperature, at constant initial pH value of 5.5 ? 0.1. The adsorption isotherms at 25, 40, 55 and 70?C suggest that the sequence of adsorption efficiency of both zeolites is Pb2+ > Zn2+ > Cd2+. The adsorption capacities of both zeolites increased with increasing temperature. The equilibrium adsorption data were best described by the Langmuir adsorption isotherm. This study revealed that the adsorption capacity of the Fe(III)-modified zeolite is much higher than that of natural zeolite for all investigated ions owing to the higher: specific adsorption caused by the new functional groups formed on the zeolite surface; ion exchange due to the presence of easily exchangeable ions; and hydroxide precipitation caused by higher point of zero charge of the Fe(III)-modified zeolite compared to natural zeolite.

scholarly journals Batch study, equilibrium and kinetics of adsorption of naphthalene using waste tyre rubber granules

2014 ◽  
Vol 4 (1) ◽  
Author(s):  
Felix A. Aisien ◽  
Andrew N. Amenaghawon ◽  
Albert I. Adinkwuye
Keyword(s):  
Contact Time ◽  
Batch Adsorption ◽  
Order Kinetic ◽  
Kinetics Of Adsorption ◽  
Isotherm Equation ◽  
Operational Variables ◽  
Langmuir Isotherm Equation ◽  
Equilibrium And Kinetics ◽  
Waste Tyre ◽  
Kinetics Of

The potential use of waste tyre rubber granules (WTRG) for the batch adsorption of naphthalene from aqueous solutions was investigated. The effect of various operational variables such as contact time, initial naphthalene concentration, adsorbent dose, size of adsorbent particles, and temperature of solution on the adsorption capacity of WTRG was evaluated. The adsorption of naphthalene by WTRG was a fast kinetic process with an equilibrium contact time of 60 min. A low temperature (5°C), small adsorbent particle size (0.212 mm) and higher adsorbent dosage favored the adsorption process. Results of isotherm studies revealed that adsorption of naphthalene was best described by the Langmuir isotherm equation (R<sup>2</sup>=0.997) while the kinetics of the process was best described by the Lagergren pseudofirst order kinetic equation (R<sup>2</sup>=0.998). This study has demonstrated the suitability of WTRG for the removal of naphthalene from aqueous solution.

scholarly journals Determination Of Adsorption Performance Of Hydrothermally Synthesized Nanocomposite

2019 ◽  
Vol 2 (3) ◽  
pp. 1218-1223
Author(s):  
Hasan Sayğılı
Keyword(s):  
Adsorption Isotherms ◽  
Adsorption Mechanism ◽  
Organic Dyes ◽  
Hydrothermal Process ◽  
Freundlich Isotherm ◽  
One Pot ◽  
Isotherm Equation ◽  
Adsorption Capacities ◽  
Langmuir Isotherm Equation

In this study, a novel nanocomposite was synthesized by a simple one-pot hydrothermal process and used as an adsorbent for the removal of methylene blue (MB) and methyl orange (MO) dyes from the aqueous medium. Overall findings from batch experiments demonstrated that the prepared nanocomposite material (Fe/GBHC) had good adsorption capacity for MB and MO. The maximum adsorption capacities of the Fe/GBHC were observed to be 11 mg/g for MB and 8.9 mg/g for MO at neutral pH of the solutions and at 303 K. To obtain the adsorption mechanism of the Fe/GBHC, the experiments of adsorption isotherms were researched. The adsorption isotherms of both dyes could be described by the Langmuir isotherm equation rather than the Freundlich isotherm equation, with a high correlation coefficient values. The results showed that the prepared Fe/GBHC material by the hydrothermal method could have potential application in the removal of organic dyes from waste water.

scholarly journals Optimization of Cd(II) adsorption condition by glycine-modified silica-based adsorbent using central composite design

2019 ◽  
Vol 22 (5) ◽  
pp. 184-191 ◽  
Author(s):  
Lisa Aprilia Indriyani ◽  
Zulhan Arif ◽  
Roza Linda ◽  
Henny Purwaningsih ◽  
Mohamad Rafi
Keyword(s):  
Optimum Condition ◽  
Solid Phase ◽  
Batch Adsorption ◽  
Maximum Adsorption Capacity ◽  
Modified Silica ◽  
Isotherm Equation ◽  
Adsorption Condition ◽  
Langmuir Isotherm Equation ◽  
Cd Adsorption ◽  
Central Composite

Silica gel (SG) is one of common adsorbent on solid phase extraction for preconcentration. Due to the low selectivity and effectiveness of adsorption to metal ions, SG should be modified. The SG was modified with d-glycine (Si-Gly) using 3-aminopropyltrimethoxysilane and glutaraldehyde as a crosslinker. Capability of Si-Gly as adsorbent for cadmium ions (Cd) was investigated using batch adsorption. The result was proved by infrared spectra. The optimum condition of Cd adsorption by the Si-Gly was obtained at pH 5, with 0.3 g of adsorbent and 11 minutes of contact time. The percentage of Cd adsorption at the optimum condition by the Si-Gly (99.34%) which is greater than the SG (89.03%). The maximum adsorption capacity of the Si-Gly is 9.77 mg/g, obtained at 400 mg/L. The Cd(II) adsorption on the SG and the Si-Gly follow the Langmuir isotherm equation.

scholarly journals USE OF MONTMORILLONITE CLAY FOR ADSORPTION MALACHITE GREEN DYE

2019 ◽  
Vol 16 (32) ◽  
pp. 279-286
Author(s):  
Marcos Antônio KLUNK ◽  
Zeban SHAH ◽  
Paulo Roberto WANDER
Keyword(s):  
Malachite Green ◽  
Retention Time ◽  
High Surface ◽  
High Surface Area ◽  
Exchange Capacity ◽  
Montmorillonite Clay ◽  
Malachite Green Dye ◽  
Low Levels ◽  
High Concentrations

Removal of malachite green dye by adsorption from aqueous solution using montmorillonite clay is reported in this work. A malachite green dye is a cationic widely used in textile industries. Due to its persistence in the aquatic environment, it becomes a problem for aquatic and terrestrial organisms. This dye can be adsorbed through various techniques, but high acquisition and operating costs preclude widespread use. Several adsorbents are available in the market, but the most outstanding are the clays, especially the montmorillonites. These clays are finely divided material ( 0.002 mm), and its adsorption properties are continuously investigated. Types of clays 2:1 (two tetrahedral to one octahedral) are called expandables. The montmorillonite has a potential for dyes removal in wastewater due to the high surface area, porosity with excellent cation exchange capacity conferring its adsorbent property. This work aims to use the montmorillonite as an adsorption system in stages to textile decolorization effluent, composed of malachite green dye, reproduced in the laboratory. The characterization of the clay gives high purity and is used as adsorbent of good quality and efficiency. The retention of dyes in the system composed of montmorillonite arranged in separation stages was efficient. The effect of dye concentration and retention time are the most important parameters used in this study. High concentrations and retention time below 24 hours resulted in low levels of removal (25%). On the other hand, the low level of initial concentration increases removal efficiency (57%). Thus, the results obtained in this work allow concluding that montmorillonite is able to removal malachite green dye.

scholarly journals Enhancing acidic dye adsorption by modified UiO-66

2020 ◽  
Vol 1 (2) ◽  
pp. 54-62
Author(s):  
Naser Al Amery ◽  
Hussein Rasool Abid ◽  
Shaobin Wang ◽  
Shaomin Liu
Keyword(s):  
Adsorption Process ◽  
Dye Adsorption ◽  
Batch Adsorption ◽  
First Order ◽  
Freundlich Isotherms ◽  
Adsorption Capacities ◽  
Pseudo Second Order ◽  
The Stability ◽  
Second Order Equations ◽  
Better Than

In this study, two improved versions of UiO-66 were successfully synthesised. Modified UiO-66 and UiO-66-Ce were characterised to confirm the integrity of the structure, the stability of functional groups on the surface and the thermal stability. Activated samples were used for removal harmful anionic dye (methyl orange) (MO) from wastewater. Batch adsorption process was relied to investigate the competition between those MOFs for removing MO from aqueous solution. Based on the results, at a higher initial concentration, the maximum MO uptake was achieved by UiO-66-Ce which was better than modified-UiO-66. They adsorbed 71.5 and 62.5 mg g-1 respectively. Langmuir and Freundlich isotherms were employed to simulate the experimental data. In addition, Pseudo first order and Pseudo second order equations were used to describe the dynamic behaviour of MO through the adsorption process. The high adsorption capacities on these adsorbents can make them promised adsorbents in industrial areas.

Impacts of Nucleating Aerosol on Florida Storms. Part I: Mesoscale Simulations

2006 ◽  
Vol 63 (7) ◽  
pp. 1752-1775 ◽  
Author(s):  
Susan C. van den Heever ◽  
Gustavo G. Carrió ◽  
William R. Cotton ◽  
Paul J. DeMott ◽  
Anthony J. Prenni
Keyword(s):  
Hydrological Cycle ◽  
Cloud Condensation Nuclei ◽  
Supercooled Liquid ◽  
Atmospheric Modeling ◽  
Saharan Dust ◽  
Regional Study ◽  
Surface Precipitation ◽  
Convective Storms ◽  
Mixing Ratios ◽  
High Concentrations

Abstract Toward the end of the Cirrus Regional Study of Tropical Anvils and Cirrus Layer–Florida Area Cirrus Experiment (CRYSTAL–FACE) field campaign held during July 2002, high concentrations of Saharan dust, which can serve as cloud condensation nuclei (CCN), giant CCN (GCCN), and ice-forming nuclei (IFN) were observed over the peninsula of Florida. To investigate the impacts of enhanced aerosol concentrations on the characteristics of convective storms and their subsequent anvil development, sensitivity tests are conducted using the Regional Atmospheric Modeling System (RAMS) model, in which the initialization profiles of CCN, GCCN, and IFN concentrations are varied. These variations are found to have significant effects on the storm dynamics and microphysical processes, as well as on the surface precipitation. Updrafts are consistently stronger as the aerosol concentrations are increased. The anvils cover a smaller area but are better organized and have larger condensate mixing ratio maxima in the cases with greater aerosol concentrations. Cloud water mass tends to increase with increasing aerosol concentrations, with enhanced GCCN concentrations having the most significant influence. Increasing either the GCCN or IFN concentrations produces the most rainfall at the surface whereas enhanced CCN concentrations reduce surface rainfall. Higher IFN concentrations produce ice at warmer temperatures and deeper anvils, but simultaneously increasing the concentrations of CCN and GCCN leads to more supercooled liquid water available for freezing and greater ice mixing ratios. Graupel mixing ratios decrease and hail mixing ratios increase with increasing aerosol concentrations. Higher concentrations of GCCN and IFN result in greater accumulated surface precipitation initially. By the end of the simulation period, however, the accumulated precipitation is the greatest for the case in which the aerosol concentrations are lowest. Such changes in the dynamical and microphysical characteristics of convective storms as a result of the variations in aerosol concentrations have potential climate consequences, both through cloud radiative effects and the hydrological cycle. The impacts of varying CCN, GCCN, and IFN concentrations on the anvils will be discussed more fully in Part II.

scholarly journals Evaluation of modified montmorillonite with di-cationic surfactants as efficient and environmentally friendly adsorbents for arsenic removal from contaminated water

2017 ◽  
Vol 18 (2) ◽  
pp. 460-472 ◽  
Author(s):  
E. Shokri ◽  
R. Yegani ◽  
B. Pourabbas ◽  
B. Ghofrani
Keyword(s):  
Contact Time ◽  
Arsenic Removal ◽  
Environmentally Friendly ◽  
Contaminated Water ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
Modified Montmorillonite ◽  
Adsorption Capacities ◽  
Modified Adsorbents ◽  
Adsorption Desorption

Abstract In this work, montmorillonite (Mt) was modified by environmentally friendly arginine (Arg) and lysine (Lys) amino acids with di-cationic groups for arsenic removal from contaminated water. The modified Mts were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, zeta potential and thermal analysis. The adsorption of As(V) onto modified Mts as a function of initial As(V) concentration, contact time and solution pH was investigated. The removal efficiency was increased with increasing the As(V) concentration and contact time; however, it was decreased with increasing solution pH. The maximum As(V) adsorption capacities of Mt-Arg and Mt-Lys were 11.5 and 11 mg/g, respectively, which were five times larger than pristine Mt. The high adsorption capacity makes them promising candidates for arsenic removal from contaminated water. The regeneration studies were carried out up to 10 cycles for both modified Mts. The obtained results confirmed that the modified adsorbents could also be effectively used for As(V) removal from water for multiple adsorption – desorption cycles.

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