scholarly journals Adsorption behavior of Cr(VI) by N-doped biochar derived from bamboo

2020 ◽  
Vol 15 (1) ◽  
pp. 170-181 ◽  
Author(s):  
Bei Chu ◽  
Kento Terao ◽  
Yoshimasa Amano ◽  
Motoi Machida
Keyword(s):  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Gas Flow ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Great Influence ◽  
High Specific Surface Area ◽  
Equilibrium Data ◽  
Initial Adsorption ◽  
Adsorption Equilibrium Data

Abstract In this study, N-doped biochar BZ-9.5AG-30 min was prepared from bamboo by using ZnCl2 as activator and heat treated at 950 °C under NH3 gas flow for the removal of Cr(VI). The adsorbent was characterized by BET, and the amount of introduced nitrogen content and nitrogen species on BZ-9.5AG-30 min was examined by CHN elemental analyzer and X-ray photoelectron spectroscopy, respectively. Herein, the obtained BZ-9.5AG-30 min had a high specific surface area (1,610 m2/g) and high N content (4.52%). The pH of the solution had a great influence on the adsorption process, indicating that the acid condition is conducive to the adsorption process of Cr(VI). Adsorption equilibrium data of Cr(VI) were analyzed by the Langmuir and the Freundlich models. The adsorption equilibrium data were well described by the Langmuir model, and BZ-9.5AG-30 min has excellent adsorption capacity for Cr(VI) (4.31 mmol/g). BZ-9.5AG-30 min showed superior recyclability, and after five times regenerations, the adsorption capacity of BZ-9.5AG-30 min still had 63% of the initial adsorption capacity.

scholarly journals Adsorption of hexavalent chromium by polyacrylonitrile-based porous carbon from aqueous solution

2018 ◽  
Vol 5 (1) ◽  
pp. 171662 ◽  
Author(s):  
Bin Feng ◽  
Wenzhong Shen ◽  
Liyi Shi ◽  
Shijie Qu
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Ph Value ◽  
Functional Materials ◽  
High Specific Surface Area ◽  
Maximum Adsorption Capacity ◽  
Elementary Analysis ◽  
Initial Adsorption

Owing to the unique microporous structure and high specific surface area, porous carbon could act as a good carrier for functional materials. In this paper, polyacrylonitrile (PAN)-based porous carbon materials (PPC-0.6-600, PPC-0.8-600, PPC-0.6-800 and PPC-0.8-800) were prepared by heating KOH at 600°C and 800 o C for the removal of Cr(VI) from aqueous solution. The adsorbent was characterized by the techniques of Fourier transform infrared spectroscopy (FT-IR), elementary analysis, scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and N 2 adsorption techniques. The results showed that the adsorption capacity increased with decreasing pH value of the initial solution. The adsorption capacity of Cr(VI) on PPC-0.8-800 was much greater than that on other materials, and maximum adsorption capacity were calculated to be 374.90 mg g −1 . Moreover, PPC-0.8-800 had superior recyclability for the removal of Cr(VI) from wastewater, about 82% of its initial adsorption capacity was retained even after five cycles. The result of kinetic simulation showed that the adsorption of Cr(VI) on the PAN-based porous carbon could be described by pseudo-second-order kinetics. The adsorption process was the ionic interaction between protonated amine groups of PPC and HCrO 4 - ions.

Thermodynamics of Cr(VI) Adsorption on Thiourea Chelating Ion Exchange Fiber

2014 ◽  
Vol 894 ◽  
pp. 121-124 ◽  
Author(s):  
Yan Qiang Jian ◽  
Ming Yu Li ◽  
Qing Xuan Zeng
Keyword(s):  
Ion Exchange ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Polypropylene Fiber ◽  
Equation Model ◽  
Batch Adsorption ◽  
Equilibrium Data ◽  
Endothermic Process ◽  
Adsorption Equilibrium Data ◽  
Ion Exchange Fiber

A chelating ion exchange fiber containing thioureido groups for the removal of Cr (VI) has been prepared from chloramethylated styrene grafted polypropylene fiber (2.96 mmol/g Cl) reacted with thiourea, batch adsorption experiments are adopted to investigate its adsorption equilibrium properties, Adsorption isotherms at various temperatures were obtained. Langmuir linear equation model can well describe the adsorption equilibrium data suggesting that the adsorption process involves both chemisorption and physisorption. The values of thermodynamic parameters, including ΔH, ΔGand ΔS, indicate that the adsorption of Cr (VI) is a spontaneous, entropy-driven and endothermic process.

scholarly journals Adsorption of Cu(II) by Poly-γ-glutamate/Apatite Nanoparticles

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 962
Author(s):  
Kuo-Yu Chen ◽  
Wei-Yu Zeng
Keyword(s):  
Adsorption Capacity ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
Gravimetric Analysis ◽  
Solution Ph ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Initial Adsorption ◽  
Adsorption Equilibrium Data

Poly-γ-glutamate/apatite (PGA-AP) nanoparticles were prepared by chemical coprecipitation method in the presence of various concentrations of poly-γ-glutamate (γ-PGA). Powder X-ray diffraction pattern and energy-dispersive spectroscopy revealed that the main crystal phase of PGA-AP was hydroxyapatite. The immobilization of γ-PGA on PGA-AP was confirmed by Fourier transform infrared spectroscopy and the relative amount of γ-PGA incorporation into PGA-AP was determined by thermal gravimetric analysis. Dynamic light scattering measurements indicated that the particle size of PGA-AP nanoparticles increased remarkably with the decrease of γ-PGA content. The adsorption of aqueous Cu(II) onto the PGA-AP nanoparticles was investigated in batch experiments with varying contact time, solution pH and temperature. Results illustrated that the adsorption of Cu(II) was very rapid during the initial adsorption period. The adsorption capacity of PGA-AP nanoparticles for Cu(II) was increased with the increase in the γ-PGA content, solution pH and temperature. At a pH of 6 and 60 °C, a higher equilibrium adsorption capacity of about 74.80 mg/g was obtained. The kinetic studies indicated that Cu(II) adsorption onto PGA-AP nanoparticles obeyed well the pseudo-second order model. The Langmuir isotherm model was fitted well to the adsorption equilibrium data. The results indicated that the adsorption behavior of PGA-AP nanoparticles for Cu(II) was mainly a monolayer chemical adsorption process. The maximum adsorption capacity of PGA-AP nanoparticles was estimated to be 78.99 mg/g.

scholarly journals COMPARISON OF STINGING NETTLE ADSORPTION PERFORMANCE TOWARDS ANIONIC AND CATIONIC DYES

2021 ◽  
Vol 55 (9-10) ◽  
pp. 1131-1142
Author(s):  
BENGÜ ERTAN ◽  
Keyword(s):  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Stinging Nettle ◽  
First Order ◽  
Equilibrium Data ◽  
Pseudo Second Order ◽  
Adsorption Equilibrium Data ◽  
Cr Uptake

Stinging nettle was used as lignocellulosic adsorbent for the removal of cationic dye – malachite green (MG), and anionic dye – Congo red (CR), from aqueous solution, without any chemical pretreatment. The adsorption equilibrium data fitted well with the Langmuir model for the adsorption of both dyes, with the calculated maximum adsorption capacity of 270.27 mgg-1 and 172.14 mgg-1 for MG and CR, respectively. The adsorption process was controlled by the pseudo-second-order model in the adsorption of MG and by the pseudo-first-order model in the adsorption of CR. The thermodynamics modelling displayed that the process was spontaneous and endothermic. The π–π electron–donor interaction, hydrogen bonds and pore diffusion may also be effective, besides electrostatic interaction between the adsorbate and the adsorbent in the mechanism of MG and CR uptake.

scholarly journals Studying Ni(II) Adsorption of Magnetite/Graphene Oxide/Chitosan Nanocomposite

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Luyen T. Tran ◽  
Hoang V. Tran ◽  
Thu D. Le ◽  
Giang L. Bach ◽  
Lam D. Tran
Keyword(s):  
Aqueous Solution ◽  
Graphene Oxide ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Entropy Change ◽  
Enthalpy Change ◽  
Nickel Ion ◽  
Adsorbent Dosage ◽  
Equilibrium Data ◽  
Adsorption Equilibrium Data

In this paper, Fe3O4/graphene oxide/chitosan (FGC) nanocomposite was synthesized using coprecipitation method for application to removal of nickel ion (Ni(II)) from aqueous solution by adsorption process. To determine residue Ni(II) ions concentration in aqueous solution after adsorption process, we have used UV-Vis spectrophotometric method, which is an effective and exact method for Ni(II) monitoring at low level by using dimethylglyoxime (DMG) as a complex reagent with Ni(II), which has a specific adsorption peak at the wavelength of 550 nm on UV-Vis spectra. A number of factors that influence Ni(II) ions adsorption capacity of FGC nanocomposite such as contact time, adsorption temperature, and adsorbent dosage were investigated. Results showed that the adsorption equilibrium is established after 70 minutes with the adsorbent dosage of 0.01 g.mL−1 at 30°C (the room temperature). The thermodynamic and kinetic parameters of this adsorption including free enthalpy change (∆G0), enthalpy change (∆H0), entropy change (∆S0), and reaction order with respect to Ni(II) ions were also determined. The Ni(II) ions adsorption equilibrium data are fitted well to the Langmuir isotherm and the maximum monolayer capacity (qmax) is 12.24 mg.g−1. Moreover, the FGC adsorbent can be recovered by an external magnet; in addition, it can be regenerated. The reusability of FGC was tested and results showed that 83.08% of removal efficiency was obtained after 3 cycles. The synthesized FGC nanocomposite with many advantages is a promising material for removal of heavy metal ions from aqueous solution to clean up the environment.

Isotherm, Kinetic and Thermodynamic Studies on Adsorption of Bromocresol Purple, Acid Red 66 and Acid Blue 40 Using Activated Carbon

2021 ◽  
Vol 21 (7) ◽  
pp. 4104-4109
Author(s):  
Jong Jib Lee ◽  
Jong Ki Jeon
Keyword(s):  
Activated Carbon ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Physical Adsorption ◽  
Isotherm Models ◽  
Bromocresol Purple ◽  
Kinetic And Thermodynamic Parameters ◽  
Equilibrium Data ◽  
Adsorption Equilibrium Data ◽  
Acid Blue

This study was conducted with a batch reaction to equilibrium isotherm, kinetic and thermodynamic parameters on adsorption of bromocresol purple (BCP), acid red 66 (AR 66) and acid blue 40 (AB 40) from aqueous solution by using activated carbon with nanopores. Freundlich and Temkin isotherm models were used to evaluate the suitability of isotherm for adsorption equilibrium data. The adsorption equilibrium was best fitted by Temkin model. The Freundlich separation factor values indicated that adsorption on the nanoporous activated carbon could effectively treat three dyes. The kinetic analysis of the adsorption process confirmed that it was more consistent with the pseudo second order model. The intraparticle diffusion was rate limiting step. The adsorption process of three dyes were endothermic because they were positive enthalpy values. The free energy values of three dyes decreased with increasing temperature, so that the spontaneity becomes higher with temperature increase. The activation energy value of three dyes were confirmed the physical adsorption.

scholarly journals Isosteric Heats of Adsorption of N2O and NO on Natural Zeolites

2019 ◽  
Vol 54 (2) ◽  
Author(s):  
Gerardo Domínguez ◽  
Rosario Hernández-Huesca ◽  
Gelacio Aguilar-Armenta
Keyword(s):  
Interaction Energy ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
High Vacuum ◽  
Natural Zeolites ◽  
Heats Of Adsorption ◽  
Freundlich Equation ◽  
Equilibrium Data ◽  
Adsorption Equilibrium Data

We studied the capacities of three natural zeolites to adsorb N2O or NO using a glass high-vacuum volumetric system that permitted characterization of the energetics of the adsorption process. Adsorption equilibrium data were analyzed using the classical Freundlich equation and the Dual–Langmuir model. We employed the Clausius–Clapeyron relationship to calculate the isosteric heats of adsorption using the equilibrium data of the isotherms measured at 273.15 K and 293.15 K. The isosteric heats of reversible adsorption of both gases were smaller than the heats of total adsorption. The interaction energy of N2O with mordenite was larger than the interaction energies of N2O with either erionite or clinoptilolite. The interaction energy of NO was found to be largest with erionite.  

Mercury Removal from Wastewater by Steamed Hoof Powder

1999 ◽  
Vol 40 (7) ◽  
pp. 109-116 ◽  
Author(s):  
M. H. Ansari ◽  
A. M. Deshkar ◽  
P. S. Kelkar ◽  
D. M. Dharmadhikari ◽  
M. Z. Hasan ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Adsorption Capacity ◽  
Adsorption Process ◽  
Adsorption Equilibrium ◽  
Light Metal ◽  
Mercury Removal ◽  
High Adsorption ◽  
Surface Sites ◽  
Ph Values ◽  
High Adsorption Capacity

Steamed Hoof Powder (SHP), size < 53μ, was observed to have high adsorption capacity for Hg(II) with >95% removal from a solution containing 100 mg/L of Hg(II) with only 0.1% (W/V) concentration of SHP. The SHP has good settling properties and gives clear and odour free effluent. Studies indicate that pH values between 2 and 10 have no effect on the adsorption of Hg(II) on SHP. Light metal ions like Na+, K+, Ca2+ and Mg2+ up to concentrations of 500 mg/L and heavy metals like Cu2+, Zn2+, Cd2+, Co2+, Pb2+, Ni2+, Mn2+, Cr3+, Cr6+, Fe2+ and Fe3+ up to concentrations of 100 mg/L do not interfere with the adsorption process. Anions like sulphate, acetate and phosphate up to concentrations of 200 mg/L do not interfere. Chloride interferes in the adsorption process when Hg(II) concentration is above 9.7 mg/L. The adsorption equilibrium was established within two hours. Studies indicate that adsorption occurs on the surface sites of the adsorbent.

scholarly journals Effective Poly (Cyclotriphosphazene-Co-4,4′-Sulfonyldiphenol)@rGO Sheets for Tetracycline Adsorption: Fabrication, Characterization, Adsorption Kinetics and Thermodynamics

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1540
Author(s):  
Muhammad Ahmad ◽  
Tehseen Nawaz ◽  
Mohammad Mujahid Alam ◽  
Yasir Abbas ◽  
Shafqat Ali ◽  
...  
Keyword(s):  
Adsorption Capacity ◽  
Surface Area ◽  
High Surface ◽  
High Surface Area ◽  
High Adsorption ◽  
Clean Environment ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
High Adsorption Capacity ◽  
Adsorption Equilibrium Data

The development of excellent drug adsorbents and clarifying the interaction mechanisms between adsorbents and adsorbates are greatly desired for a clean environment. Herein, we report that a reduced graphene oxide modified sheeted polyphosphazene (rGO/poly (cyclotriphosphazene-co-4,4′-sulfonyldiphenol)) defined as PZS on rGO was used to remove the tetracycline (TC) drug from an aqueous solution. Compared to PZS microspheres, the adsorption capacity of sheeted PZS@rGO exhibited a high adsorption capacity of 496 mg/g. The adsorption equilibrium data well obeyed the Langmuir isotherm model, and the kinetics isotherm was fitted to the pseudo-second-order model. Thermodynamic analysis showed that the adsorption of TC was an exothermic, spontaneous process. Furthermore, we highlighted the importance of the surface modification of PZS by the introduction of rGO, which tremendously increased the surface area necessary for high adsorption. Along with high surface area, electrostatic attractions, H-bonding, π-π stacking and Lewis acid-base interactions were involved in the high adsorption capacity of PZS@rGO. Furthermore, we also proposed the mechanism of TC adsorption via PZS@rGO.

scholarly journals Fabrication of Carboxymethylcellulose/Metal-Organic Framework Beads for Removal of Pb(II) from Aqueous Solution

Materials ◽  
2019 ◽  
Vol 12 (6) ◽  
pp. 942 ◽  
Author(s):  
Huo-Xi Jin ◽  
Hong Xu ◽  
Nan Wang ◽  
Li-Ye Yang ◽  
Yang-Guang Wang ◽  
...  
Keyword(s):  
Aqueous Solutions ◽  
Adsorption Capacity ◽  
Photoelectron Spectroscopy ◽  
Langmuir Isotherm ◽  
Adsorption Equilibrium ◽  
Isotherm Model ◽  
Maximum Adsorption Capacity ◽  
X Ray ◽  
Metal Organic ◽  
Langmuir Isotherm Model

The ability to remove toxic heavy metals, such as Pb(II), from the environment is an important objective from both human-health and ecological perspectives. Herein, we describe the fabrication of a novel carboxymethylcellulose-coated metal organic material (MOF-5–CMC) adsorbent that removed lead ions from aqueous solutions. The adsorption material was characterized by Fourier-transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and X-ray photoelectron spectroscopy. We studied the functions of the contact time, pH, the original concentration of the Pb(II) solution, and adsorption temperature on adsorption capacity. MOF-5–CMC beads exhibit good adsorption performance; the maximum adsorption capacity obtained from the Langmuir isotherm-model is 322.58 mg/g, and the adsorption equilibrium was reached in 120 min at a concentration of 300 mg/L. The adsorption kinetics is well described by pseudo-second-order kinetics, and the adsorption equilibrium data are well fitted to the Langmuir isotherm model (R2 = 0.988). Thermodynamics experiments indicate that the adsorption process is both spontaneous and endothermic. In addition, the adsorbent is reusable. We conclude that MOF-5–CMC is a good adsorbent that can be used to remove Pb(II) from aqueous solutions.

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