scholarly journals Sono-assisted adsorption of acid violet 7 and basic violet 10 dyes from aqueous solutions: Evaluation of isotherm and kinetic parameters

2020 ◽  
Vol 27 (1) ◽  
pp. 200287-0
Author(s):  
Burcu Ileri

In this study, the removal of acid violet 7 (AV7) and basic violet 10 (BV10) synthetic dyes was investigated using fly ash alone, ultrasound (40 kHz) alone, and combined ultrasound/fly ash with various experimental parameters such as fly ash dose, contact time, and initial concentration of dye. The adsorption capacity of the ultrasound/fly ash process increased from 5.10 to 7.43 mg g-1 for AV7, and increased from 5.16 to 7.51 mg g-1 for BV10 compared with using fly ash alone. The sono–assisted adsorption process was successful in improving the dye uptake capacity with cavitation bubbles and acoustic waves, and thus AV7 and BV10 were removed with a shorter contact time and lower fly ash dose. Obtained regeneration and reuse experiment results showed that the fly ash could be reused for four consecutive cycles of the sono–assisted adsorption process, while fly ash could be reused for two consecutive cycles of the adsorption process. The adsorption kinetics for AV7 and BV10 onto fly ash fitted Lagergren’s first–order adsorption kinetic model well. The Langmuir isotherm best described the adsorption with fly ash alone and ultrasound/fly ash process for AV7 and BV10.

2012 ◽  
Vol 9 (1) ◽  
pp. 153-159 ◽  
Author(s):  
Baghdad Science Journal

Equilibrium adsorption isotherm for the removal of trifluralin from aqueous solutions using ? –alumina clay has been studied. The result shows that the isotherms were S3 according Giels classification. The effects of various experimental parameters such as contact time, adsorbent dosage, effect of pH and temperature of trifluralin on the adsorption capacities have been investigated. The adsorption isotherms were obtained by obeying freundlich adsorption isotherm with (R2 = 0.91249-0.8149). The thermodynamic parameters have been calculated by using the adsorption process at five different temperature, the values of ?H, ?G and ?S were (_1.0625) kj. mol-1, (7.628 - 7.831) kj.mol-1 and (_2.7966 - _2.9162) kg. k-1. mol-1 respectively. The kinetic study of adsorption process has been studied depending on three kinetic equations: 1- Allergen equation 2- Morris –weber eguation 3- Reichenberg eguation. In general, the result shows the isotherm were on ?- alumina according to Giels classification.? –alumina and thermodynamic


2018 ◽  
Vol 792 ◽  
pp. 140-144
Author(s):  
Jumaeri ◽  
Eko Sri Kunarti

Adsorption of Cr(III) and Cr(VI) in aqueous solution by the zeolite A from coal fly ash at various conditions has been carried out. Zeolite A was synthesized from fly ash through modified alkaline fusion hydrothermal process in a reactor stainless steel. Adsorption is carried out by direct contact between the adsorbent and adsorbate in an adsorption batch. Zeolite A from fly ash (ZA-FA) of 0.01 g was mixed with 20 mL both Cr(III) and Cr(VI) at various pH, contact time and initial concentration, in a flask Erlenmeyer 50 mL. The result showed that pH conditions of adsorption process, affect the adsorption ability of zeolite A to Cr(III) and Cr(VI) in aqueous solution. The adsorption of Cr(III) and Cr(VI) on zeolite A reached a maximum at pH 6 and time contact 120 minutes. The adsorption of Cr(III) on zeolite A increased from 3.4 mg/g at pH 3 and achieved a maximum adsorption of 42.67 mg/g at pH 6. At higher pH (7-8) the Cr(III) adsorption tends decreases. The adsorption ability of ZA-FA to Cr(III) is higher than that of Cr(VI) in aqueous solution. The Cr(III) adsorption process on ZA-FA follows the pseudo-order 2 kinetics model.


2021 ◽  
Vol 10 (2) ◽  
pp. 70-76
Author(s):  
Fatimah ◽  
Siti Hardianti ◽  
Stephen Octaviannus

The purpose of this study was to determine the response and performance of fly ash as an adsorbent activated by HCl and impregnated with FeCl3 to absorb phenol. In this study, the fly ash activation process was carried out using 8 M HCl for 2 hours and impregnated with 2% FeCl3 for 2 hours. Activated and impregnated fly ash was analyzed using a Scanning Electron Microscope-Energy Dispersive Spectrophotometer (SEM-EDX). The results of the activated and impregnated fly ash surface using SEM-EDX showed that there were changes in morphology and functional groups. Then activated and impregnated fly ash was used to absorb phenol at a time variation of 60 minutes, 120 minutes, 180 minutes, 240 minutes and 300 minutes. At 180 minutes of contact time, the equilibrium point is obtained with an absorption efficiency of 90.5%. Second-order pseudo kinetics were used for phenol adsorption by Fe+ impregnated fly ash (R2 = 0.9916). The isotherm models used in the phenol adsorption process by fly ash impregnated with Fe+ are Langmuir Isotherm (R2 = 0.9927) and Freundlich Isotherm (R2 = 0.9984), which means that the adsorption process occurs in multi-layer and mono-layers.


1993 ◽  
Vol 28 (2) ◽  
pp. 369-384 ◽  
Author(s):  
T. Viraraghavan ◽  
Murali M. Dronamraju

Abstract The effectiveness of fly ash in adsorbing copper, nickel and zinc was studied by conducting batch kinetic and isotherm studies. The effect of contact time, pH, initial concentration of the adsorbate, and temperature on the adsorption process was studied. Fly ash was found to be an effective adsorbent. The contact time necessary to attain equilibrium was found to be two hours. Maximum adsorption occurred in the pH range of 3.0 to 3.5. The Langmuir and Freundlich models were found to be applicable to the adsorption data of copper, nickel and zinc. Thermodynamic parameters suggested the exothermic nature of the adsorption process.


1992 ◽  
Vol 9 (3) ◽  
pp. 130-147 ◽  
Author(s):  
A. Kapoor ◽  
T. Viraraghavan

The effectiveness of fly ash in adsorbing mercury from wastewater has been studied. Batch kinetic and isotherm studies have been carried out to determine the effect of contact time, pH and temperature on the adsorption. It has been found that a contact time of 2 h is necessary for the adsorption to reach equilibrium. The optimum pH was found to be between 5.0 and 5.5. The adsorption isotherm data were described adequately by both the Langmuir and the Freundlich models. The adsorption process was found to be endothermic.


2018 ◽  
Vol 34 (6) ◽  
pp. 2859-2866
Author(s):  
Ahde El-Imache ◽  
Kamar Ouazzani

In this study, the Moroccan Olive Core (OC) was chosen for the preparation of a bio-adsorbent for the purpose of using it as a natural support to remove two synthetic dyes: Methyl Blue (MB) and Crystal Violet (CV) from aqueous solutions. Tow adsorbent characterization techniques were used: Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). Influence of some parameters is studied to characterize the adsorption process: contact time (0-45 min), temperature (25 -100 °C) and initial concentration of MB and CV (10-30 mg.l-1). Langmuir, Freundlich and Dubinin-Radushkevich isotherm models were used to describe the adsorption equilibrium. The equilibrium is perfectly described by the Freundlich model whose correlation coefficient is equal to 0.995 for MB and 0.991 for CV. Thermodynamic parameters were valued, and they showed that, for both dyes, the adsorption on MOC is endothermic and spontaneous.


2018 ◽  
Vol 766 ◽  
pp. 65-70 ◽  
Author(s):  
Sujitra Onutai ◽  
Takaomi Kobayashi ◽  
Parjaree Thavorniti ◽  
Sirithan Jiemsirilers

Geopolymer particles from waste coal fly ash were prepared in order to investigate adsorption process of Cadmium ions. The aim of the study is to focus on factors which affect adsorption process of heavy metals on geopolymer materials. The raw fly ash was mixed with sodium hydroxide solution and sodium silicate solution. After that geopolymer was cured at 80 °C for 24 hr. The sample was ground and washed until pH=7. The obtained geopolymer particles were dried at 60 oC. The raw materials and geopolymer were characterized. The XRD results showed a highly amorphous structure in obtained geopolymer. The major components of waste coal fly ash and synthesized geopolymer were SiO2, Al2O3, Fe2O3 and CaO. The BET surface area of fly ash and geopolymer particles were 0.83 m2/g and 85.01 m2/g, respectively. The adsorption conditions (initial concentration from 10-120 mg/L, temperature at 25-45 °C, pH of cadmium ions solution from 1-5, 0.02-0.14 g. of geopolymer and contact time for 5-180 min) were studied. From removal efficiency results, synthesized geopolymer had high removal capacity for cadmium ions (Cd2+). At pH 5 of solution, the highest Cd2+ removal capacity was obtained. In addition, the removal efficiency increases with an increasing geopolymer dosage, contact time and a decreasing of Cd2+ initial concentration. Moreover, both Langmuir and Freundlich models were investigated for studying adsorption isotherm. The result showed Langmuir model is more suitable for geopolymer adsorption of cadmium ion in aqueous solution than Freundlich model.


Author(s):  
Joshua O. Ighalo ◽  
Lois T. Arowoyele ◽  
Samuel Ogunniyi ◽  
Comfort A. Adeyanju ◽  
Folasade M. Oladipo-Emmanuel ◽  
...  

Background: The presence of pollutants in polluted water is not singularized hence pollutant species are constantly in competition for active sites during the adsorption process. A key advantage of competitive adsorption studies is that it informs on the adsorbent performance in real water treatment applications. Objective: This study aims to investigate the competitive adsorption of Pb(II), Cu(II), Fe(II) and Zn(II) using elephant grass (Pennisetum purpureum) biochar and hybrid biochar from LDPE. Method: The produced biochar was characterised by Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). The effect of adsorption parameters, equilibrium isotherm modelling and parametric studies were conducted based on data from the batch adsorption experiments. Results: For both adsorbents, the removal efficiency was >99% over the domain of the entire investigation for dosage and contact time suggesting that they are very efficient for removing multiple heavy metals from aqueous media. It was observed that removal efficiency was optimal at 2 g/l dosage and contact time of 20 minutes for both adsorbent types. The Elovich isotherm and the pseudo-second order kinetic models were best-fit for the competitive adsorption process. Conclusion: The study was able to successfully reveal that biomass biochar from elephant grass and hybrid biochar from LDPE can be used as effective adsorbent material for the removal of heavy metals from aqueous media. This study bears a positive implication for environmental protection and solid waste management.


Toxics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 111
Author(s):  
Maria Mihăilescu ◽  
Adina Negrea ◽  
Mihaela Ciopec ◽  
Petru Negrea ◽  
Narcis Duțeanu ◽  
...  

Gold is one of the precious metals with multiple uses, whose deposits are much smaller than the global production needs. Therefore, extracting maximum gold quantities from industrial diluted solutions is a must. Am-L-GA is a new material, obtained by an Amberlite XAD7-type commercial resin, functionalized through saturation with L-glutamic acid, whose adsorption capacity has been proved to be higher than those of other materials utilized for gold adsorption. In this context, this article presents the results of a factorial design experiment for optimizing the gold recovery from residual solutions resulting from the electronics industry using Am-L-GA. Firstly, the material was characterized using atomic force microscopy (AFM), to emphasize the material’s characteristics, essential for the adsorption quality. Then, the study showed that among the parameters taken into account in the analysis (pH, temperature, initial gold concentration, and contact time), the initial gold concentration in the solution plays a determinant role in the removal process and the contact time has a slightly positive effect, whereas the pH and temperature do not influence the adsorption capacity. The maximum adsorption capacity of 29.27 mg/L was obtained by optimizing the adsorption process, with the control factors having the following values: contact time ~106 min, initial Au(III) concentration of ~164 mg/L, pH = 4, and temperature of 25 °C. It is highlighted that the factorial design method is an excellent instrument to determine the effects of different factors influencing the adsorption process. The method can be applied for any adsorption process if it is necessary to reduce the number of experiments, to diminish the resources or time consumption, or for expanding the investigation domain above the experimental limits.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Kahina Bouhadjra ◽  
Wahiba Lemlikchi ◽  
Azedine Ferhati ◽  
Samuel Mignard

AbstractIn the present study, the potato peel waste (PP) was used for the removal of the anionic dye Cibacron Blue P3R from an aqueous solution, activated with phosphoric acid (PPa) and calcined at 800 °C (PPc). The materials were characterized by Scanning Electron Microscope, Energy dispersive X-ray analysis and Fourier Transform Infrared Spectroscopy. The effects of various experimental parameters (pH, dye concentration, contact time) were also studied. The experimental results have shown that PPc has a greater capacity compared to pp and ppa. The capacity of PP bio-char (PPc) is 270.3 mg g−1 compared to PP (100 mg g−1) and PPa (125 mg g−1). Equilibrium experiments at 180 min for all materials were carried out at optimum pH (2.2): 76.41, 88.6 and 94% for PP, PPa and PPc respectively; and the Langmuir models agreed very well with experimental data. The ability of sorbent for the sorption of CB dye follows this order: calcined > activated > native materials. Potato peel biochar (PPc) can be considered a promising adsorbent for removing persistent dyes from water.


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