scholarly journals ADSORPTION OF FLUORIDE USING SIO2 NANOPARTICLES AS ADSORBENT

Author(s):  
Davoud Balarak ◽  
Yousef Mahdavi ◽  
Ali Joghatayi

Presence of Fluoride in water is safe and effective when used as directed, but it can be harmful at high doses. In the present paper SiO2 nanoparticles as a adsorbent is used for removal of fluoride from aqueous solution. The effect of various operating parameters such as initial concentration of F-, Contact time, adsorbent dosage and pH were investigated. Equilibrium isotherms were used to identify the possible mechanism of the adsorption process. Maximum adsorption capacity of the SiO2 nanoparticles was 49.95 mg/g at PH=6, contact time 20 min, initial concentration of 25 mg/L, and 25±2 ◦C temperatures, when 99.4% of Fwere removed. The adsorption equilibriums were analyzed by Langmuir and Freundlich isotherm models. It was found that the data fitted to Langmuir (R2=0.992) better than Freundlich (R2=0.943) model. Kinetic analyses were conducted using pseudo first-and second-order models. The regression results showed that the adsorption kinetics was more accurately represented by a pseudo second-order model. These results indicate that SiO2 nanoparticles can be used as an effective, low-cost adsorbent to remove fluoride from aqueous solution.

2014 ◽  
Vol 2014 ◽  
pp. 1-8 ◽  
Author(s):  
I. Osasona ◽  
O. O. Ajayi ◽  
A. O. Adebayo

The feasibility of using powdered cow hooves (CH) for removing Ni2+ from aqueous solution was investigated through batch studies. The study was conducted to determine the effect of pH, adsorbent dosage, contact time, adsorbent particle size, and temperature on the adsorption capacity of CH. Equilibrium studies were conducted using initial concentration of Ni2+ ranging from 15 to 100 mgL−1 at 208, 308, and 318 K, respectively. The results of our investigation at room temperature indicated that maximum adsorption of Ni2+ occurred at pH 7 and contact time of 20 minutes. The thermodynamics of the adsorption of Ni2+ onto CH showed that the process was spontaneous and endothermic. Langmuir, Freundlich, and Dubinin-Radushkevich (D-R) isotherm models were used to quantitatively analysed the equilibrium data. The equilibrium data were best fitted by Freundlich isotherm model, while the adsorption kinetics was well described by pseudo-second-order kinetic equation. The mean adsorption energy obtained from the D-R isotherm revealed that the adsorption process was dominated by physical adsorption. Powdered cow hooves could be utilized as a low-cost adsorbent at room temperature under the conditions of pH 7 and a contact time of 20 minutes for the removal of Ni(II) from aqueous solution.


2012 ◽  
Vol 09 (17) ◽  
pp. 48-59
Author(s):  
Carina Pitwak MAGDALENA ◽  
Denise Alves FUNGARO ◽  
Patricia CUNICO

Textile effluents, when not correctly treated, cause a high impact to the environment. The synthetic dyes are used in the fibber dying process, but part of them is discarded to receiving water body. The adsorption is a technique that has been used successfully for an effective removal of color. In this work, the adsorption of reactive dye Remazol Red RB from aqueous solution using zeolite of coal ash as low cost adsorbent was studied. The zeolite was synthesized by hydrothermal treatment with NaOH solution. The effect of experimental parameters such as contact time, pH, temperature and adding salt was investigated. The kinetics studies indicated that the adsorption followed the pseudo-second-order model with correlation coefficients > 0.99. The equilibrium was reached after 360 min of contact time. The experimental data were analyzed using Langmuir and Freundlich isotherm models and the data fitted well to the Langmuir isotherm. The maximum adsorption capacity of zeolite of coal ash for Remazol Vermelho RB was 1.20 mg g-1 with adsorption efficiency between 75 and 91%. The dye adsorption was more efficient in the presence of salts.


2018 ◽  
Vol 877 ◽  
pp. 13-19
Author(s):  
Bhargavi Gunturu ◽  
Geethalakshmi Ramakrishnan ◽  
Renganathan Sahadevan

In the present study, the efficiency of biosorbent derived form Pongamiapinata to remove a basic textile dye Methylene Blue from an aqueous solution was evaluated in batch system. The influence of adsorption parameters such as biosorbent dosage (0.2-1.0g/L), PH (2-10) and initial dye concentration (30-110 mg/L) on the biosorption process was studied. It was noticed that adsorbent dosage has negative effect on dye uptake, could be due to reduced mass transfer rate of dye on to adsorbent. High equilibrium uptake was observed at PH 8. However, initial dye concentration has shown linear relationship with dye uptake. As the dye concentration increases, the number of dye molecules available to be adsorbed on to adsorbent surface increases. Equilibrium isotherms for the adsorption of methylene blue was analyzed through Langmuir and Freundlich isotherm models. The data best fit with Freundlich model than Langmuir isotherm model, suggesting the adsorption was by multilayer mechanism. Maximum adsorption capacity (Q ̊) was found to be 40.49mg/g. It can be concluded from the study that the adsorbent derived from P.pinnata can be a potential low cost competent of activated carbon for textile dyes removal.


Clay Minerals ◽  
2015 ◽  
Vol 50 (1) ◽  
pp. 65-76 ◽  
Author(s):  
Hayrunnisa Nadaroglu ◽  
Ekrem Kalkan ◽  
Neslihan Celebi ◽  
Esen Tasgin

AbstractIn this study, a clinoptilolite modified with apolaccase was used to adsorb Reactive Black 5 (RB5) dye from aqueous solution using the batch procedure. The influences of pH, contact time, temperature and absorbent dosage on the adsorption were investigated. The optimum adsorption was obtained at pH = 6, contact time = 60 min, temperature = 25ºC and adsorbent dosages of 1.62 and 1.59 mg/50 mL per gram of clinoptilolite and of apolaccase-modified clinoptilolite (LMC), respectively). The adsorption experimental data fitted both the Langmuir and Freundlich isotherm models well. In addition, pseudo-first-order and pseudo-second-order kinetics were used to study the kinetics of RB5 dye adsorption onto natural clinoptilolite and LMC. Adsorption appears to follow pseudo-second-order kinetics with a high correlation coefficient. Thermodynamic parameters such as changes in the free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) of adsorption were calculated. The thermodynamic parameters indicate that the adsorption of RB5 dye onto LMC was less spontaneous, feasible and endothermic. The LMC can be used as an alternative low-cost adsorbent for the dye removal from aqueous solutions.


Author(s):  
Syed Muhammad Salman ◽  
Sardar Muhammad ◽  
Mahmood Iqbal ◽  
Muhammad Aijaz ◽  
Muhammad Siddique ◽  
...  

  The removal of Pb (II) and Cd (II) ions from aqueous solution by a novel low-cost biosorbent; chemically modified Syzygium cumini leaves (CMSCL) was studied. The effects of biomass dosage, pH, concentration, temperature and contact time were investigated. Characterization of CMSCL was carried out by FT-IR spectroscopy, pore size, and surface area analyzer. The maximum biosorption capability of CMSCL for Pb (II) and Cd (II) ions was 104 and 50 mg/g at optimum conditions of pH 6 and 7, biomass dosage of 5 g/L, contact time of 120 and 90 min and temperature of 50 and 40 0C, respectively. The experimental data was analyzed using pseudo-first order and pseudo-second order kinetics models. The biosorption of Pb (II) and Cd (II) followed pseudo-second order model. Langmuir, Freundlich and Temkin adsorption isotherm models were applied to explain the removal of heavy metal ions by CMSCL biosorbent. Langmuir isotherm model fitted better than other isotherm models. Thermodynamics parameters such as �H0, �G0 and �S0 showed that the biosorption of Pb (II) and Cd (II) ions onto CMSCL was spontaneous, exothermic and feasible under examined conditions. The occurrence of various functional groups and change in the absorption frequency after metal uptake indicates that complexation was the main mechanism involved in the process of biosorption. Based on the present investigation, it was proved that CMSCL is an effective, alternative and economical biosorbent for the removal of Pb (II) and Cd (II) ions. Keywords: 


2013 ◽  
Vol 2013 ◽  
pp. 1-9 ◽  
Author(s):  
Öznur Dülger ◽  
Fatma Turak ◽  
Kadir Turhan ◽  
Mahmure Özgür

Sumac Leaves (SL) (Rhus Coriaria L. ) were investigated as an inexpensive and effective adsorbent for the adsorption of methylene blue (MB) from aqueous solution. The effects of initial dye concentration, initial solution pH, phases contact time, and adsorbent dose on the adsorption of MB on SL were investigated. The amount of dye adsorbed was found to vary with initial solution pH, Sumac Leaves dose, MB concentration, and phases contact time. The Langmuir and Freundlich adsorption models were evaluated using the experimental data and the experimental results showed that the Langmuir model fits better than the Freundlich model. The maximum adsorption capacity was found to be 151.69 mg/g from the Langmuir isotherm model at 25°C. The value of the monolayer saturation capacity of SL was comparable to the adsorption capacities of some other adsorbent materials for MB. The adsorption rate data were analyzed according to the pseudo-first order kinetic and pseudo-second order kinetic models and intraparticle diffusion model. It was found that kinetic followed a pseudo-second order model.


2017 ◽  
Vol 36 (1-2) ◽  
pp. 149-169 ◽  
Author(s):  
Fatemeh Gorzin ◽  
MM Bahri Rasht Abadi

In the present work, a new low-cost activated carbon was prepared from paper mill sludge in order to remove Cr(VI) ions from aqueous solution. The effects of adsorbent dosage, pH, contact time, metal ion concentrations, and temperature on adsorption efficiency were studied by experimental tests. The maximum equilibrium uptake of Cr(VI) by the adsorbent was 23.18 mg g−1 at optimum pH = 4.0, contact time of 180 min, and temperature of 45℃. Analysis of equilibrium adsorption data in terms of several isotherm models revealed that Langmuir isotherm with respect to Freundlich isotherm indicates better agreement with the experimental data. The kinetics of Cr(VI) adsorption onto activated carbon was described with the pseudo-second-order model which indicates the dominance of chemisorption mechanism. Thermodynamic parameters indicated that the Cr(VI) adsorption onto adsorbent was feasible in nature, spontaneous, and endothermic.


2017 ◽  
Vol 13 (27) ◽  
pp. 425
Author(s):  
Azeh Yakubu ◽  
Gabriel Ademola Olatunji ◽  
Folahan Amoo Adekola

This investigation was conducted to evaluate the adsorption capacity of nanoparticles of cellulose origin. Nanoparticles were synthesized by acid hydrolysis of microcrystalline cellulose/cellulose acetate using 64% H3PO4 and characterized using FTIR, XRD, TGA-DTGA, BET and SEM analysis. Adsorption kinetics of Pb (II) ions in aqueous solution was investigated and the effect of initial concentration, pH, time, adsorbent dosage and solution temperature. The results showed that adsorption increased with increasing concentration with removal efficiencies of 60% and 92.99% for Azeh2 and Azeh10 respectively for initial lead concentration of 3 mg/g. The effects of contact time showed that adsorption maximum was attained within 24h of contact time. The maximum adsorption capacity and removal efficiency were achieved at pH6. Small dose of adsorbent had better performance. The kinetics of adsorption was best described by the pseudo-second-Order model while the adsorption mechanism was chemisorption and pore diffusion based on intra-particle diffusion model. The isotherm model was Freundlich. Though, all tested isotherm models relatively showed good correlation coefficients ranging from 0.969-1.000. The adsorption process was exothermic for Azeh-TDI, with a negative value of -12.812 X 103 KJ/mol. This indicates that the adsorption process for Pb by Azeh-TDI was spontaneous. Adsorption by Azeh2 was endothermic in nature.


2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Dhiraj Dutta ◽  
Jyoti Prasad Borah ◽  
Amrit Puzari

Results of investigation on adsorption of Mn2+ from aqueous solution by manganese oxide-coated hollow polymethylmethacrylate microspheres (MHPM) are reported here. This is the first report on Mn-coated hollow polymer as a substitute for widely used materials like green sand or MN-coated sand. Hollow polymethylmethacrylate (HPM) was prepared by using a literature procedure. Manganese oxide (MnO) was coated on the surface of HPM (MHPM) by using the electroless plating technique. The HPM and MHPM were characterized by using optical microscopy (OM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). Optical and scanning micrographs were used to monitor the surface properties of the coated layer which revealed the presence of MnO on the surface of HPM. TGA showed the presence of 4-5% of MnO in MHPM. Adsorption isotherm studies were carried out as a function of pH, initial ion concentration, and contact time, to determine the adsorption efficiency for removal of Mn2+ from contaminated water by the synthesized MHPM. The isotherm results showed that the maximum adsorption capacity of MnO-coated HPM to remove manganese contaminants from water is 8.373 mg/g. The obtained R 2 values of Langmuir isotherm and Freundlich isotherm models were 1 and 0.87, respectively. Therefore, R 2 magnitude confirmed that the Langmuir model is best suited for Mn2+ adsorption by a monolayer of MHPM adsorbent. The material developed shows higher adsorption capacity even at a higher concentration of solute ions, which is not usually observed with similar materials of this kind. Overall findings indicate that MHPM is a very potential lightweight adsorbent for removal of Mn2+ from the aqueous solution because of its low density and high surface area.


2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Joshua N. Edokpayi ◽  
Samson O. Alayande ◽  
Ahmed Adetoro ◽  
John O. Odiyo

In this study, the potential for pulverized raw macadamia nut shell (MNS) for the sequestration of methylene blue from aqueous media was assessed. The sorbent was characterized using scanning electron microscopy for surface morphology, functional group analysis was performed with a Fourier-transform infrared spectrometer (FT-IR), and Brunauer–Emmett–Teller (BET) isotherm was used for surface area elucidation. The effects of contact time, sorbent dosage, particle size, pH, and change in a solution matrix were studied. Equilibrium data were fitted using Temkin, Langmuir, and Freundlich adsorption isotherm models. The sorption kinetics was studied using the Lagergren pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. The feasibility of the study was established from the thermodynamic studies. A surface area of 2.763 m2/g was obtained. The equilibrium and kinetics of sorption was best described by the Langmuir and the pseudo-second-order models, respectively. The sorption process was spontaneous (−ΔG0=28.72−31.77 kJ/mol) and endothermic in nature (ΔH0=17.45 kJ/mol). The positive value of ΔS0 (0.15 kJ/molK) implies increased randomness of the sorbate molecules at the surface of the sorbent. This study presents sustainable management of wastewater using MNS as a potential low-cost sorbent for dye decontamination from aqueous solution.


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