Kinetics and Equilibrium Studies on Adsorption of Dimethylformamide by Macroporous Chitosan Membranes

2011 ◽  
Vol 233-235 ◽  
pp. 1141-1145
Author(s):  
Si Fang Li ◽  
Qiang Chen ◽  
Miao Liu

The adsorption of dimethylformamide (DMF) by macroporous chitosan membranes using silica gel as porogen is studied. The morphology, porosity and DMF adsorption capacity of the macroporous chitosan membrane were measured. SEM photographs show the pores in the membrane dispersed uniformly. DMF adsorption capacity of the macroporous chitosan membranes reached 145 mg/g. Adsorption isotherm of DMF on the macroporous chitosan membranes was determined and correlated with Langmuir and Freundlich equations. The adsorption equilibrium data fitted well with Freundlich equation. The adsorption kinetics was found to follow the pseudo second-order kinetic model.

2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.


2016 ◽  
Vol 16 (4) ◽  
pp. 992-1001 ◽  
Author(s):  
Jasmina Nikić ◽  
Jasmina Agbaba ◽  
Malcolm Watson ◽  
Snežana Maletić ◽  
Jelena Molnar Jazić ◽  
...  

A series of Fe–Mn binary oxides with different Fe:Mn ratios (1:1, 3:1, 6:1, 9:1) were synthesized to investigate the optimal Fe:Mn ratio for the removal of As(III) and As(V). Batch experiments were performed to determine the rate of adsorption and equilibrium isotherms. Adsorption kinetics were well described by the pseudo-second-order kinetic model for both As(III) and As(V). The adsorption equilibrium data fitted well to Langmuir and Freundlich isotherms. The maximum As(V) sorption capacity was observed at an Fe:Mn ratio of 6:1 (65.0 mg/g), whereas maximum As(III) uptake was at Fe:Mn ratio 3:1 (46.9 mg/g). Arsenic levels in real water samples were reduced from 37 μg/l to below the EU Water Framework Directive limit (10 μg/L) after treatment with Fe–Mn adsorbents.


2012 ◽  
Vol 446-449 ◽  
pp. 2960-2963
Author(s):  
Jing Yan Song ◽  
Jing Yang

The adsorption properties of the attapulgite and the rectorite were investigated by removal of a cationic dye, methylene blue (MB) from aqueous solution. The attapulgite and the rectorite were characterized by Fourier transform infrared (FT-IR) spectroscopy, Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM). The analysis of the isotherm equilibrium data using the Langmuir and Freundlich equations showed that the data fitted better with Langmuir model. Pseudo-first-order and pseudo-second-order models were considered to evaluate the rate parameters. The experimental data were well described by the pseudo-second-order kinetic model. The results indicate that the attapulgite exhibited higher adsorption capacity for MB than rectorite and could be employed as a low-cost alternative in wastewater treatment for the removal of cationic dyes.


2012 ◽  
Vol 77 (3) ◽  
pp. 393-405 ◽  
Author(s):  
Zavvar Mousavi ◽  
Abdorrahman Hosseinifar ◽  
Vahdat Jahed

Polyacrylamide (PAA), as an adsorbent was investigated for the removal of Ni(II) and Cr(III) metal ions from their synthesized aqueous solutions. The different variables affecting the adsorption capacity of the adsorbent such as contact time, pH of the sorption medium, metal ions concentration and temperature of the solution were investigated on a batch sorption basis. The adsorption equilibrium data fitted best with the Langmuir isotherm model. The maximum adsorption capacities found to be 84.03 and 32.67 mg g-1 of the polyacrylamide for Cr(III) and Ni(II), respectively. Three kinetic models including the pseudo-first-order, pseudo-second-order and intraparticle diffusion equations were selected to follow the adsorption process. Kinetic parameters such as rate constants, equilibrium adsorption capacities and related correlation coefficients, for each kinetic model were calculated and discussed. It was indicated that the adsorption of both ions onto polyacrylamide could be described by the pseudo-second-order kinetic model. Different thermodynamic parameters such as ?H?, ?S? and ?G? have also been evaluated and it has been found that the sorption was feasible, spontaneous and exothermic.


2020 ◽  
Vol 27 (2) ◽  
pp. 271-280
Author(s):  
Inga Zinicovscaia ◽  
Nikita Yushin ◽  
Ana Pantelica ◽  
Štefan Demčák ◽  
Andreea Mitu ◽  
...  

AbstractThe biosorption of lithium from batch systems by Arthrospira (Spirulina) platensis biomass was studied. Adsorption capacity of the biosorbent was investigated as a function of contact time, initial metals concentration and pH values. Lithium content in biomass was determined using Proton Induced Gamma Emission technique. The ability of spirulina biomass for lithium biosorption showed a maximum at the pH = 11. Equilibrium data fitted well with the Langmuir model with maximum adsorption capacity of 1.75 mg/g, while the kinetic data were best described using the pseudo second-order kinetic model. The IR spectrum of the Li-loaded biomass revealed that lithium ions could be primarily bind to –OH, –COOH, –NH, –NH2, and –NH3 groups present on biosorbent surface. Arthrospira platensis biomass could be applied as environmentally friendly sorbent for lithium removal from wastewater.


2013 ◽  
Vol 295-298 ◽  
pp. 1154-1160 ◽  
Author(s):  
Guo Zhi Deng ◽  
Xue Yuan Wang ◽  
Xian Yang Shi ◽  
Qian Qian Hong

The objective of this paper is to investigate the feasibility of phenol adsorption from aqueous solution by Pinus massoniana biochar. Adsorption conditions, including contact time, initial phenol concentration, adsorbent dosage, strength of salt ions and pH, have been investigated by batch experiments. Equilibrium can be reached in 24 h for phenol from 50 to 250 mg• L-1. The optimum pH value for this kind of biochar is 5.0. The amount of phenol adsorbed per unit decreases with the increase in adsorbent dosage. The existence of salt ions makes negligible influence on the equilibrium adsorption capacity. The experimental data is analyzed by the Freundlich and Langmuir isotherm models. Equilibrium data fits well to the Freundlich model. Adsorption kinetics models are deduced and the pseudo-second-order kinetic model provides a good correlation for the adsorbent process. The results show that the Pinus massoniana biochar can be utilized as an effective adsorption material for the removal of phenol from aqueous solution.


Author(s):  
Mohamed Nasser Sahmoune ◽  
Krim Louhab ◽  
Aissa Boukhiar

Dead streptomyces rimosus was found to be an effective biosorbent for the removal of chromium from industrial tanning effluents. A sorption level of 65 mg/g was observed at pH 4.8 while the precipitation effect augmented this value at a higher pH range. Chromium desorption increased with decreasing desorption agents pH (including HCl and H2SO4) to a maximum value of 95% at approximately zero pH. The biosorption data of trivalent chromium by streptomyces rimosus has been used for kinetic studies based on fractional power, Elovich, pseudo-first order and pseudo-second order rate expressions. The time-dependent Cr (III) biosorption data were well-described by a pseudo-second-order kinetic model. The intraparticle diffusion is not the rate-limiting step for the whole reaction. It was found that the biosorption equilibrium data fit well with the Langmuir model.


2015 ◽  
Vol 5 (1) ◽  
pp. 45
Author(s):  
Tchuifon Tchuifon Donald Raoul ◽  
Nche George Ndifor-Angwafor ◽  
Ngakou Sadeu Christian ◽  
Kamgaing Théophile ◽  
Ngomo Horace Manga ◽  
...  

<p>The present study is based on the adsorption of cadmium (II) ions on rice husk and egussi peeling, unmodified and modified with nitric acid in aqueous solution, using batch technique. It was carried out as a function of contact time, dosage, pH and initial concentration. The equilibrium time was achieved within 25 minutes for unmodified rice husk (Glu NT) and 20 minutes for unmodified egussi peeling (Cuc NT) with an adsorbed quantity of 13.18 mg/g. In the case of modified materials, we obtained 15 minutes for modified rice husk (Glu HNO3) and 10 minutes for modified egussi peeling (Cuc HNO3) with an adsorbed quantity of 18.77 mg/g. The maximum biosorption occurred at pH 5.5 for all biosorbents. The adsorbent mass for maximum adsorption was 0.4 g giving an adsorption capacity of 62.02 % for unmodified adsorbents. In the case of modified adsorbents, the minimal mass at which maximum adsorption occurred was 0.4 g giving an adsorption capacity of 98.33 % and 0.6 g giving an adsorption capacity of 98.33 % for modified rice husk and egussi peeling respectively. The adsorbent/adsorbate equilibrium was well described by the pseudo-second order kinetic model and by Langmuir’s and Freundlich adsorption model. This models showed that the adsorption of cadmium (II) is a chemisorption process.</p>


SAINTIFIK ◽  
2020 ◽  
Vol 6 (2) ◽  
pp. 104-115
Author(s):  
Agusriyadin Agusriyadin

Penelitian ini bertujuan untuk menguji kemampuan AK dan AKPM dalam mengadsorpsi ion Cu (II), pengaruh parameter adsorpsi dan mekanisme adsorpsi. AK dan AKP Madsorben dibuat dari residu ampas kelapa. Adsorben dikarakterisasi dengan FTIR, SEM dan EDS. Pengaruh parameter adsorpsi seperti pH awal, dosis adsorben, waktu kontak dan konsentrasi ion Cu (II) awal diperiksa untuk menentukan kondisi optimum serapan tembaga (II). Ion Cu (II) yang teradsorpsi diukur berdasarkan pada konsentrasi Ion Cu (II) sebelum dan sesudah adsorpsi menggunakan metode AAS. Hasil karakterisasi menunjukkan bahwa struktur pori dan gugus fungsi tersedia pada permukaan adsorben. Menurut percobaan efek pH, kapasitas adsorpsi maksimum dicapai pada pH 7. Waktu kontak optimal dan konsentrasi tembaga awal (II) ditemukan masing-masing pada 120 menit dan 100 mg L-1. Data eksperimental sesuai dengan model kinetik orde dua orde dua, dan Langmuir isoterm adsorpsi yang diperoleh paling sesuai dengan data adsorpsi. Kapasitas adsorpsi maksimum adsorben ditemukan menjadi 4,73 dan 6,46 mg g-1 pada kondisi optimal. The results of characterization showed that the pore structure and the functional groups were available on adsorbent surface. According to the pH effect experiments, the maximum adsorption capacity was achieved at pH 7. Optimum contact time and initial copper(II) concentration were found at 120 min and 100 mg L-1, respectively. The experimental data were comply with the pseudo-second-order kinetic model, and Langmuir adsorption isotherm obtained best fitted the adsorption data. The maximum adsorption capacity of the adsorbents was found to be 4.73 and 6.46 mg g-1 at optimum conditions.


Author(s):  
Xiaochun Yin ◽  
Nadi Zhang ◽  
Meixia Du ◽  
Hai Zhu ◽  
Ting Ke

Abstract In this paper, a series of bio-adsorbents (LR-NaOH, LR-Na2CO3 and LR-CA) were successfully prepared by modifying Licorice Residue with NaOH, Na2CO3 and citric acid, which were used as the adsorbents to remove Cu2+ from wastewater. The morphology and structure of bio-adsorbents were characterized by Fourier Transform Infrared, SEM, TG and XRD. Using static adsorption experiments, the effects of the adsorbent dosage, the solution pH, the adsorption time, and the initial Cu2+ concentration on the adsorption performance of the adsorbents were investigated. The results showed that the adsorption process of Cu2+ by the bio-adsorbents can be described by pseudo-second order kinetic model and the Langmuir model. The surface structure of the LR-NaOH, LR-Na2CO3 and LR-CA changed obviously, and the surface-active groups increased. The adsorption capacity of raw LR was 21.56 mg/g, LR-NaOH, LR- Na2CO3 significantly enhanced this value up to 43.65 mg/g, 43.55 mg/g, respectively. After four adsorption-desorption processes, the adsorption capacity of LR-NaOH also maintained about 73%. Therefore, LR-NaOH would be a promising adsorbent for removing Cu2+ from wastewater, and the simple strategy towards preparation of adsorbent from the waste residue can be as a potential approach using in the water treatment.


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