scholarly journals Adsorption of Tea Polyphenols using Microporous Starch: A Study of Kinetics, Equilibrium and Thermodynamics

Molecules ◽  
2019 ◽  
Vol 24 (8) ◽  
pp. 1449 ◽  
Author(s):  
Xianchun Hu ◽  
Xianfeng Du
Keyword(s):  
Physical Adsorption ◽  
Tea Polyphenols ◽  
Adsorptive Capacity ◽  
Partial Hydrolysis ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Long Term Storage ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir

Microporous starch (MPS) granules were formed by the partial hydrolysis of starch using α–amylase and glucoamylase. Due to its biodegradability and safety, MPS was employed to adsorb tea polyphenols (TPS) based on their microporous characteristics. The influences of solution pH, time, initial concentration and temperature on the adsorptive capacity were investigated. The adsorption kinetics data conformed to the pseudo second–order kinetics model, and the equilibrium adsorption data were well described by the Langmuir isotherm model. According to the fitting of the adsorption isotherm formula, the maximum adsorption capacity of TPS onto MPS at pH 6.7 and T = 293 K was approximately 63.1 mg/g. The thermodynamic parameters suggested that the adsorption of TPS onto MPS was spontaneous and exothermic. Fourier transform infrared (FT–IR) analysis and the thermodynamics data were consistent with a physical adsorption mechanism. In addition, MPS-loaded TPS had better stability during long-term storage at ambient temperature.

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 Application of Fe-Impregnated Biochar from Cattle Manure for Removing Pentavalent Antimony from Aqueous Solution

2021 ◽  
Vol 11 (19) ◽  
pp. 9257
Author(s):  
Seong-Jik Park ◽  
Yeon-Jin Lee ◽  
Jin-Kyu Kang ◽  
Je-Chan Lee ◽  
Chang-Gu Lee
Keyword(s):  
Energy Dispersive Spectrometer ◽  
Inhibitory Effect ◽  
Cattle Manure ◽  
Model Fit ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Pentavalent Antimony ◽  
Equilibrium Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

This study assessed the applicability of Fe-impregnated biochar derived from cattle manure (Fe-CMB) as an adsorbent for removing Sb(V) from aqueous solutions and investigated the Sb(V) adsorption mechanism. Fe-CMB was mainly composed of C, O, Cl, Fe, Ca, and P, and the adsorption of Sb(V) onto Fe-CMB was identified using an energy dispersive spectrometer and Fourier transform infrared spectroscopy. Sb(V) adsorption reached equilibrium within 6 h, and the Sb(V) adsorption data as a function of time were well described by the pseudo-second-order model. The Langmuir isotherm model fit the equilibrium data better than the Freundlich model. The maximum adsorption capacity of Fe-CMB for Sb(V) obtained from the Langmuir model was 58.3 mg/g. Thermodynamic analysis of Sb(V) adsorption by Fe-CMB indicated that the adsorption process was exothermic and spontaneous. The Sb(V) removal percentage increased with the Fe-CMB dose, which achieved a removal of 98.5% at 10.0 g/L Fe-CMB. Increasing the solution pH from 3 to 11 slightly reduced Sb(V) adsorption by 6.5%. The inhibitory effect of anions on Sb(V) adsorption followed the order: Cl− ≈ NO3− < SO42− < HCO3− < PO43−.

scholarly journals Adsorption of Lead(II) Ions from Aqueous Solution onto Lignin

2009 ◽  
Vol 27 (4) ◽  
pp. 435-445 ◽  
Author(s):  
Laura Bulgariu ◽  
Dumitru Bulgariu ◽  
Theodor Malutan ◽  
Matei Macoveanu
Keyword(s):  
Aqueous Solution ◽  
Ion Concentration ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Solution Ph ◽  
Batch System ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

The adsorption of lead(II) ions from aqueous solution onto lignin was investigated in this study. Thus, the influence of the initial solution pH, the lignin dosage, the initial Pb(II) ion concentration and the contact time were investigated at room temperature (19 ± 0.5 °C) in a batch system. Adsorption equilibrium was approached within 30 min. The adsorption kinetic data could be well described by the pseudo-second-order kinetic model, while the equilibrium data were well fitted using the Langmuir isotherm model. A maximum adsorption capacity of 32.36 mg/g was observed. The results of this study indicate that lignin has the potential to become an effective and economical adsorbent for the removal of Pb(II) ions from industrial wastewaters.

scholarly journals Pectin/Activated Carbon-Based Porous Microsphere for Pb2+ Adsorption: Characterization and Adsorption Behaviour

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2453
Author(s):  
Ri-si Wang ◽  
Ya Li ◽  
Xi-xiang Shuai ◽  
Rui-hong Liang ◽  
Jun Chen ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Profile Analysis ◽  
Removal Rate ◽  
Physical Adsorption ◽  
Kinetic Studies ◽  
Maximum Adsorption Capacity ◽  
Texture Profile ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Adsorption Desorption

The development of effective heavy metal adsorbents has always been the goal of environmentalists. Pectin/activated carbon microspheres (P/ACs) were prepared through simple gelation without chemical crosslinking and utilized for adsorption of Pb2+. Scanning electron microscopy (SEM) revealed that the addition of activated carbon increased the porosity of the microsphere. Texture profile analysis showed good mechanical strength of P/ACs compared with original pectin microspheres. Kinetic studies found that the adsorption process followed a pseudo-second-order model, and the adsorption rate was controlled by film diffusion. Adsorption isotherms were described well by a Langmuir isotherm model, and the maximum adsorption capacity was estimated to be 279.33 mg/g. The P/ACs with the highest activated carbon (P/AC2:3) maintained a removal rate over 95.5% after 10 adsorption/desorption cycles. SEM-energy-dispersive X-ray spectrum and XPS analysis suggested a potential mechanism of adsorption are ion exchange between Pb2+ and Ca2+, electronic adsorption, formation of complexes, and physical adsorption of P/ACs. All the above results indicated the P/ACs may be a good candidate for the adsorption of Pb2+.

scholarly journals Selective adsorption behavior of Cd2+ imprinted acrylamide-crosslinked-poly(alginic acid) magnetic polymers: fabrication, characterization, adsorption performance and mechanism

2020 ◽  
Author(s):  
Zuyu Li ◽  
Shuangzhen Guo ◽  
Da Li ◽  
Lihua Zang
Keyword(s):  
Metal Ions ◽  
Adsorption Capacity ◽  
Alginic Acid ◽  
Selective Adsorption ◽  
Physical Adsorption ◽  
Maximum Adsorption Capacity ◽  
Magnetic Adsorbent ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
The Impact

Abstract Poly(acrylamide) grafted and glutaraldehyde-crosslinked alginic acid nano-magnetic adsorbent (AAMA) was prepared by selecting Cd2+ as a template ion. Scanning electron microscope (SEM), Thermo-gravimetric analyzer (TGA), Vibrating sample magnetometer (VSM) and Infrared Spectroscopy (IR)were used to characterize the morphology and structure of AAMA. The adsorption of AAMA for different metal ions was compared and the impact of various factors for adsorption of Cd2+ was systematically investigated. These results suggested that the AAMA was the aggregates of Fe3O4 nanoparticles with a diameter of about 50–100 nm. and had selectivity for Cd2+ adsorption. The maximum adsorption capacity for Cd2+ is 175 mg/g at pH 5.0 and 303 K. The experimental data were well described by the Langmuir isotherm model and pseudo-second-order model. The parameters of adsorption thermodynamics concluded that the adsorption progress is spontaneous and endothermic in nature. The parameters of adsorption activation energy suggested that there is physical adsorption and chemisorption on the adsorption of metal ions. AAMA could be regenerated by EDTA and still keep 71% adsorption capacity in the fifth consecutive adsorption-regeneration cycle. Therefore, AAMA would be useful as a selective and high adsorption capacity nano-magnetic adsorbent in the removal of Cd2+ from wastewater.

Adsorption of methyl orange dye onto biochar adsorbent prepared from chicken manure

2018 ◽  
Vol 77 (5) ◽  
pp. 1303-1312 ◽  
Author(s):  
Jiangang Yu ◽  
Xingwen Zhang ◽  
Dong Wang ◽  
Ping Li
Keyword(s):  
Aqueous Solution ◽  
Methyl Orange ◽  
Chicken Manure ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Equilibrium Data ◽  
Intra Particle Diffusion ◽  
Endothermic Process ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order

Abstract In this work, the biochar adsorbent carboxymethyl cellulose (CMC), was prepared from the pyrolysis (600 °C, 120 min) of chicken manure for the removal of methyl orange (MO) from aqueous solution, and its physicochemical properties were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectra (FTIR). The experimental parameters including agitation speed, initial solution pH, biochar dosage and contact time on the adsorption properties of MO from aqueous solution onto CMC were investigated in batch experiments. The kinetic adsorption of different initial concentration could be accurately described by the pseudo-second-order model and the overall rate process was apparently influenced by external mass transfer and intra-particle diffusion. Furthermore, the Langmuir isotherm model showed a better fit with equilibrium data (R2 &gt; 0.99), with the maximum adsorption capacity of 39.47 mg·g−1 at 25 °C. Moreover, the thermodynamic parameters indicated that the adsorption of MO onto CMC was a spontaneous and endothermic process. The results of this study indicated that CMC could be used as a promising biomass adsorbent material for aqueous solutions containing MO.

scholarly journals Functionalization of Fe3O4/SiO2 with N-(2-Aminoethyl)-3-aminopropyl for Sorption of [AuCl4]-

2018 ◽  
Vol 16 (2) ◽  
pp. 130 ◽  
Author(s):  
Nuryono Nuryono ◽  
Mighfar Syukur ◽  
Agus Kuncaka ◽  
Satya Candra Wibawa Sakti
Keyword(s):  
Homogeneous System ◽  
Maximum Adsorption Capacity ◽  
Order Model ◽  
Transmission Electron ◽  
Coating Method ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
Adsorption Desorption ◽  
Aminopropyl Group

Synthesis of Fe3O4/SiO2 modified with N-(2-aminoethyl)-3-aminopropyl group (Fe3O4/SiO2/ED) via coating method and its application for adsorption-desorption of anionic gold in aqueous solution have been conducted. The synthesized product was characterized with an X-ray diffractometer (XRD), a Fourier transform infrared (FT-IR) spectrophotometer and a transmission electron microscopy (TEM). Adsorption of Au(III) was conducted in a batch system and the variables included pH, contact time, and initial concentration were investigated. Results showed that magnetite/silica has been successfully functionalized with N-(2-aminoethyl)-3-aminopropyl in a homogeneous system. Kinetics study showed that adsorption of Au(III) followed the pseudo-second order model with rate constant of 0.710 g mmol L-1min-1. Furthermore, the experimental data fitted well with the Langmuir isotherm model with the maximum adsorption capacity for Au(III) of 142.9 mg g-1 and the energy of 25.0 kJ mol-1. Gold loaded on the Fe3O4/SiO2/ED could be easily desorbed with 0.2 mol L-1 HCl containing 2 wt.% of thiourea with recovery of 99.8%. Fe3O4/SiO2/ED was reusable and stable in 5 cycles of adsorption-desorption with recovery more than 90%. Fe3O4/SiO2/ED showed high selectivity towards Au(III) in the multimetal system Au(III)/Cu(II)/Cr(VI) with the coefficient selectivity for αAu-Cu of 227.5and for αAu-Cr of 12.3.

scholarly journals Green Synthesis of A Novel MXene–CS Composite Applied in Treatment of Cr(VI) Contaminated Aqueous Solution

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 524
Author(s):  
Hongyou Wan ◽  
Lan Nan ◽  
Huikai Geng ◽  
Wei Zhang ◽  
Huanhuan Shi
Keyword(s):  
Photoelectron Spectroscopy ◽  
Environmental Concern ◽  
Maximum Adsorption Capacity ◽  
Aqueous Environment ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Xrd Patterns

The considerable amount of Cr(VI) pollutants in the aqueous environment is a significant environmental concern that cannot be ignored. A series of novel Mxene–CS inorganic–organic composite nanomaterials synthesized by using the solution reaction method was applied to treat the Cr(VI) contaminated water. The Mxene–CS composites were characterized through SEM (scanning electron microscope), XRD (X–ray diffraction), XPS (X–ray photoelectron spectroscopy), and FTIR (Fourier transform infrared). The XRD patterns (observed at 2θ of 18.1°, 35.8°, 41.5°, and 60.1°) and the FT–IR spectra (-NH2 group for 1635 and 1517 cm−1, and -OH group for 3482 cm−1) illustrated that CS was successfully loaded on the Mxene. The effects of solution pH, the dosage of Mxene–CS, and duration time on the adsorption of Cr(VI) by synthesized Mxene–CS were investigated. The removal efficiency of Cr(VI) was increased from 12.9% to 40.5% with Mxene–CS dosage ranging from 0.02 to 0.12 g/L. The adsorption process could be well fitted by the pseudo–second–order kinetics model, indicating chemisorption occurred. The Langmuir isotherm model could be better to describe the process with a maximum adsorption capacity of 43.1 mg/g. The prepared novel Mxene–CS composite was considered as an alternative for adsorption of heavy metals from wastewater.

scholarly journals Preparation, characterization, and efficient chromium (VI) adsorption of phosphoric acid activated carbon from furfural residue: an industrial waste

2020 ◽  
Vol 82 (12) ◽  
pp. 2864-2876
Author(s):  
Hao Zhang ◽  
Yiming Sun ◽  
Shen Li ◽  
Xihui Li ◽  
Haifeng Zhou ◽  
...  
Keyword(s):  
Activated Carbon ◽  
Bet Surface Area ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Chromium Vi ◽  
Furfural Residue ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
H3po4 Activation

Abstract Furfural residue (FR) is an inevitable by-product of industrial furfural production. If FR is not managed properly, it will result in environmental problems. In this study, FR was used as a novel precursor for activated carbon (AC) production by H3PO4 activation under different conditions. Under optimum conditions, the prepared FRAC had high BET surface area (1,316.7 m2/g) and micro-mesoporous structures. The prepared FRAC was then used for the adsorption of Cr(VI). The effect of solution pH, contact time, initial Cr(VI) concentration, and temperature was systematically studied. Characterization of the adsorption process indicated that the experimental data were well-fitted by the Langmuir isotherm model and pseudo-second-order kinetics model. The maximum adsorption capacity of 454.6 mg/g was achieved at pH 2.0, which was highly comparable to the other ACs reported in the literatures. The preparation of FRAC using H3PO4 activation can make use of FR's characteristic acidity, which could make it preferable in practical industrial production.

scholarly journals Uptake of As(V) from Groundwater Using Fe-Mn Oxides Modified Kaolin Clay: Physicochemical Characterization and Adsorption Data Modeling

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1245 ◽  
Author(s):  
Rabelani Mudzielwana ◽  
Mugera Wilson Gitari ◽  
Patrick Ndungu
Keyword(s):  
Arsenic Removal ◽  
Physicochemical Characterization ◽  
Kaolin Clay ◽  
Maximum Adsorption Capacity ◽  
Solution Ph ◽  
Adsorbate Concentration ◽  
Adsorption Data ◽  
Langmuir Isotherm Model ◽  
Pseudo Second Order ◽  
Mn Oxides

The present study evaluated the effectiveness of Fe-Mn modified kaolin clay in the uptake of As(V) from the solution. The elemental composition was characterized using X-ray fluorescence (XRF), while the surface morphology was characterized using Scanning Electron Microscopy (SEM). The surface area, pore diameter, and pore volume were determined using Brunauer, Emmett, and Teller (BET) and Barrett-Joyner-Halenda (BJH) techniques. The efficiency of the Arsenic removal of the adsorbent was evaluated using batch experiments. The results showed that the percentage of As(V) removal is optimum at acidic pH and decreased as the solution pH becomes more alkaline. The adsorption kinetics data fitted better to pseudo-second-order compared to the pseudo-first-order of reaction kinetics. The adsorption isotherm data fitted to the Langmuir isotherm model showing a maximum adsorption capacity of 2.44 mg/g, adsorbate concentration range of 1–30 mg/L, and adsorbent dosage of 0.4 g/100 mL. The value of ∆G° of the thermodynamic parameter was found to be negative, while ∆H° and ∆S° were found to be positive. For the regeneration-reuse study, the percentage of removal was found to be >85% after the sixth cycle of reuse. The results obtained from this study showed that Fe-Mn modified kaolin (FMK) is suitable for use in the uptake of As(V) from groundwater.

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