Adsorption Characteristics of Directly Modified Bentonite

2013 ◽  
Vol 826 ◽  
pp. 263-266
Author(s):  
Gui Ping Wang ◽  
Gui Yan Wang ◽  
Chun Yan Cao

Directly modified bentonite was obtained by directly adding modifier cetyl trimethyl ammonium bromide (CTMAB) to sodium bentonite.The modified bentonites adsorption performance to methyl orange and methylene blue was studied, and it was compared with modified bentonite prepared by classical method. The results show that directly modified bentonite has a greater and faster absorption for both methyl orange and methylene blue; the relationship between adsorption quantity and equilibrium concentration conforms to the Langmuir isotherm equation; absorption kinetics is in accordance with the secondary dynamics equation.

Author(s):  
Saraa Muwafaq Ibrahim ◽  
Ziad T. Abd Ali

Batch experiments have been studied to remove methylene blue dye (MB) from aqueous solution using modified bentonite. The modified bentonite was synthesized by replacing exchangeable calcium cations in natural bentonite with cationic surfactant cetyl trimethyl ammonium bromide (CTAB). The characteristics of modified bentonite were studied using different analysis such as Scanning electronic microscopy (SEM), Fourier transform infrared spectrometry (FTIR) and surface area. Where SEM shows the natural bentonite has a porous structure, a rough and uneven appearance with scattered and different block structure sizes, while the modified bentonite surface morphology was smooth and supplemented by a limited number of holes. On other hand, (FTIR) analysis that proved NH group aliphatic and aromatic group of MB and silanol group are responsible for the sorption of contaminate. The organic matter peaks at 2848 and 2930 cm-1 in the spectra of modified bentonite which are sharper than those of the natural bentonite were assigned to the CH2 scissor vibration band and the symmetrical CH3 stretching absorption band, respectively, also the 2930 cm-1 peak is assigned to CH stretching band. The batch study was provided the maximum removal efficiency (99.99 % MB) with a sorption capacity of 129.87 mg/g at specified conditions (100 mg/L, 25℃, pH 11 and 250rpm). The sorption isotherm data fitted well with the Freundlich isotherm model. The kinetic studies were revealed that the sorption follows a pseudo-second-order kinetic model which indicates chemisorption between sorbent and sorbate molecules.


2011 ◽  
Vol 239-242 ◽  
pp. 2310-2316 ◽  
Author(s):  
Chun Mei Niu ◽  
Shao Ying Li ◽  
Dong Huang

Crosslinked Carboxymethyl Konjac Glucomannan(CMKGM) with substitution degrees ofcarboxymethyl group(DS)0.265, 0.457 and 0.586 were prepared through reaction of monochloroacetic acid, konjac glucomannan(KGM) and epichlorohydrin and used to adsorb Cu(II) from the aqueous solutions of copper nitrate. The effects of pH, adsorbent dose, initial concentration of Cu(II), adsorption time and temperature on adsorption capacity were investigated. The results showed that adsorption capacity increased with an increasing DS of the carboxymethyl groups. Equilibrium adsorption time was 20 min or so and was independent on DS. The adsorption followed Langmuir isotherm equation. Ligand ion adsorption between carboxymethyl group and Cu(II) was thought to be predominate in the process of adsorption according to the relationship between DS and thermodynamic parameters. CMKGM can be used as cheaper and more effective adsorbents.


2021 ◽  
Vol 406 ◽  
pp. 348-363
Author(s):  
Larbi Haddad ◽  
Abdelkader Hima ◽  
Belkhir Dadamoussa ◽  
Asma Messai Aoun

In this study, a local mineral clay was used as an adsorbent for the elimination of a cationic dye: methylene blue (MB), in an aqueous solution by adsorption technique. Early on, we performed mineralogical and textural analyses of a clay sample using various techniques, namely X-ray diffraction, Brunauer-Emmett-Teller analysis and Fourier-transform infrared spectroscopy. The experimental results showed that this adsorbent is a mesoporous and non-swelling clay with illite and kaolinite as the major components with a specific area of about 110m2/g. The study of MB adsorption on the clay was carried out by optimizing the conditions of adsorption, notably the initial concentration of pollutant C0, the mass of clay m, the contact time t, the potential of hydrogen of the solution pH and the temperature T. Experimental results have shown that the equilibrium data are well adjusted by a Langmuir isotherm equation. Thermodynamic parameters such as the changes in Gibbs free energy, enthalpy, and entropy were determined from batch experiments. Results revealed that the adsorption of MB onto illitic clay was endothermic and spontaneous process. Kinetic modeling was also carried out. Experimental data adjusted the kinetic model of pseudo-second order with two stages of intraparticle diffusion.


2019 ◽  
Vol 2019 ◽  
pp. 1-7
Author(s):  
Ha Xuan Linh ◽  
Ngo Thi Thu ◽  
Tran Quoc Toan ◽  
Do Tra Huong ◽  
Bui Thanh Giang ◽  
...  

In this work, the mixture of red mud slurry and inorganic salt ((NH4)2SO4) has been used as an electrolyte for electrochemical activation of graphite. The red mud-activated graphite composite was then used as an adsorbent for removing methylene blue from aqueous solution by the batch method. The effect of pH, contact time, adsorbent dosage, and the initial concentration of methylene blue was investigated. The optimal condition was found at pH 6, contact time 120 min, and amount of adsorbent 1 mg/L. The maximum adsorption capacity was found to be 89.28 mg/g based on the Langmuir isotherm equation, suggesting that the red mud-activated graphite composite is a very potential adsorbent for removing methylene blue and is also used in other coloured wastewater treatments.


2012 ◽  
Vol 476-478 ◽  
pp. 1365-1369 ◽  
Author(s):  
Xiao Hua Yu ◽  
Hai Liang Lü ◽  
Guo Wei Zhou ◽  
Li Guo Zhou ◽  
Yong Chun Zhang

In the present study, three kinds of zeolite (NaP1, NaA, and NaX) were synthesized by a hydrothermal method. These zeolites were modified by cetyl trimethyl-ammonium bromide (CTAB), and used to adsorb methyl orange (MO). NaP1 had the highest adsorption capacity, with a 99.7% MO removal percentage. An orthogonal experiment was conducted to determine the influence of adsorbent dosage, solution pH, initial MO concentration, contact time, and solution temperature on NaP1. The results showed that the initial MO concentration had the most significant effect. The adsorption isotherms of the zeolites are in a good agreement with the Langmuir formula, and the adsorption mechanism is also discussed.


2012 ◽  
Vol 557-559 ◽  
pp. 427-433 ◽  
Author(s):  
Cheng Qun Huang ◽  
Xue Zhang ◽  
Da Chuan Qiu ◽  
Hong Juan Wei

Mesoporous silica microspheres (MSM) with diameter about 100 nm were prepared by hydrothermal synthesis using cetyl trimethyl ammonium bromide(CTAB) as template agent and tetraethyl orthosilicate(TEOS) as silica source. And they were characterized byscanning electron microscopy (SEM) , N2 adsorption-desorption analysis , infrared spectroscopy (FT-IR). Then methylene blue adsorption test was investigated. Effect of pH, temperature of the adsorption of methylene blue onto MSM were studied. The adsorption amount onto MSM increased with the initial pH-value of the solution in the range of 3~10. Alkaline was more favorable to adsorption. The adsorption amount onto MSM decreased with the initial temperature of the solution at 22 °C~ 45 °C. low-temperature was more favorable to adsorption. The adsorption isotherm of methylene blue on MSM could be described by the Langmuir model.


2018 ◽  
Vol 18 (4) ◽  
pp. 733 ◽  
Author(s):  
Alexandr Ivanovich Vezentsev ◽  
Dang Minh Thuy ◽  
Lidia Fedotovna Goldovskaya-Peristaya ◽  
Nadezhda Alexandrovna Glukhareva

The adsorption of methylene blue from model aqueous solutions on bentonite-like clay, hydroxyapatite, and a composite sorbent has been investigated. The kinetic and thermodynamic parameters of adsorption in the temperature range 298–333 К have been calculated. The process is found to obey Langmuir isotherm equation. It is spontaneous but slightly endothermic. The maximal sorption capacity of the composite sorbent toward methylene blue is 175.4 mg/g at 25 °С that is 1.3 times more than that for bentonite-like clay and 17.8 times more than that for hydroxyapatite. Kinetics of the process is due to the combination of external and internal diffusion and can be described better by the model of pseudo-second order reaction.


2014 ◽  
Vol 2014 ◽  
pp. 1-5 ◽  
Author(s):  
Wenfeng Guo ◽  
Heping Li ◽  
Haisheng Ma ◽  
Weixiu Teng

Bi2MoO6single-crystallites were synthesized by a simple hydrothermal method in the presence of surfactant sodium dodecyl sulfate (SDS), polyvinyl pyrrolidone (PVP), or cetyl trimethyl ammonium bromide (CTAB). The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet-visible diffuse reflectance spectra (UV-vis DRS) techniques. The photocatalytic activities of the as-fabricated Bi2MoO6samples were measured for the degradation of methylene blue (MB) under the Xe light illumination. It is shown that the introduction of surfactant have a crucial influence on the size and morphology of the Bi2MoO6product. Among the as-fabricated Bi2MoO6samples, the ones derived hydrothermally with CTAB showed outstanding photocatalytic activities for the addressed reaction under simulated sunlight irradiation, attributed to the ultrafine nanocrystals and the higher surface areas.


2016 ◽  
Vol 74 (10) ◽  
pp. 2437-2445 ◽  
Author(s):  
Carlos Alberto Policiano Almeida ◽  
Tânia Marina Palhano Zanela ◽  
Clodoaldo Machado ◽  
Juan Antônio Altamirano Flores ◽  
Luiz Fernando Scheibe ◽  
...  

An aluminosilicate waste (AW) was investigated as adsorbent for methylene blue (MB) dye. AW was characterized by petrography, X-ray diffractometry, X-ray fluorescence, scanning electron microscopy, thermogravimetry and zeta potential measurements. It was found that AW contains kaolinite, and other minor components such as quartz, muscovite, smectite, siderite, pyrite and organic compounds. The chemical composition of AW is mainly SiO2 (49%) and Al2O3 (23%) and it has negative superficial charge above pH 1.73. Adsorption of MB dye was studied in a batch system under different conditions of initial dye concentration, contact time and temperature. The isothermal data from batch experiments were fitted to Langmuir and Freundlich equations, with a better fit shown by the Langmuir isotherm equation. Also, pseudo-first-order, pseudo-second-order and intraparticle diffusion models were considered to evaluate the rate parameters. The experimental data fitted the pseudo-first-order kinetic model best. Thermodynamic parameters were calculated, showing the adsorption to be an endothermic yet spontaneous process, with the activation energy of +37.8 kJ mol–1. The results indicate that AW adsorbs MB efficiently, and can be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.


Author(s):  
Shailesh R. Sheth ◽  
Jayesh R. Bellare

Specimen support and astigmatism correction in Electron Microscopy are at least two areas in which lacey polymer films find extensive applications. Although their preparation has been studied for a very long time, present techniques still suffer from incomplete release of the film from its substrate and presence of a large number of pseudo holes in the film. Our method ensures complete removal of the entire lacey film from the substrate and fewer pseudo holes by pre-treating the substrate with Gum Arabic, which acts as a film release agent.The method is based on the classical condensation technique for preparing lacey films which is essentially deposition of minute water or ice droplets on the substrate and laying the polymer film over it, so that micro holes are formed corresponding to the droplets. A microscope glass slide (the substrate) is immersed in 2.0% (w/v) aq. CTAB (cetyl trimethyl ammonium bromide)-0.22% (w/v) aq.


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