Synthesis of a new magnetic nanocomposite hydrogel based on poly(vinyl acetate-co-maleic anhydride)/melamine for efficient dye removal

2019 ◽  
Vol 52 (1) ◽  
pp. 70-89 ◽  
Author(s):  
Hanieh Rezazadeh ◽  
Peyman Najafi Moghadam ◽  
Saeideh Ehsanimehr ◽  
Amir Reza Fareghi
Keyword(s):  
Maleic Anhydride ◽  
Vinyl Acetate ◽  
Magnetic Nanocomposite ◽  
Order Kinetic ◽  
Nanocomposite Hydrogel ◽  
Solution Ph ◽  
One Pot ◽  
X Ray ◽  
Order Kinetic Model ◽  
Magnetic Nanocomposite Hydrogel

In this work, we fabricated a novel magnetic nanocomposite hydrogel based on poly(vinyl acetate- co-maleic anhydride)/melamine. A simple one-pot method was applied to fabricate the nanocomposite, and its adsorption capacity was investigated using Congo red (CR) dye. Then, the effects of a variety of parameters such as adsorbent dosage, solution pH, initial dye concentration, and contact time on the efficiency of the adsorbent were evaluated. The optimal adsorption of CR on the adsorbent was observed at pH 5 with 10 mg adsorbent and 10 mg L−1 initial dye concentrations where the adsorption efficiency reached above 90%. The Langmuir model was applied for fitting the adsorption isotherm of CR obtained on the proposed nanocomposite hydrogel, and it was observed that the adsorption process most probably followed a pseudo-second-order kinetic model. The obtained results showed that the proposed nanocomposite adsorbent could be used in water treatment. It was characterized with different techniques including X-ray diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, vibrating sample magnetometer, and energy dispersive X-ray.

scholarly journals The Removal of Uranium and Thorium from Their Aqueous Solutions by 8-Hydroxyquinoline Immobilized Bentonite

Minerals ◽  
2019 ◽  
Vol 9 (10) ◽  
pp. 626 ◽  
Author(s):  
Salah ◽  
Gaber ◽  
Kandil
Keyword(s):  
Aqueous Solutions ◽  
Metal Ions ◽  
Langmuir Isotherm ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
X Ray Diffraction ◽  
Solution Ph ◽  
X Ray ◽  
Order Kinetic Model ◽  
Pseudo Second Order

The sorption of uranium and thorium from their aqueous solutions by using 8-hydroxyquinoline modified Na-bentonite (HQ-bentonite) was investigated by the batch technique. Na-bentonite and HQ-bentonite were characterized by X-ray fluorescence (XRF), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier Transform Infrared (FTIR) spectroscopy. Factors that influence the sorption of uranium and thorium onto HQ-bentonite such as solution pH, contact time, initial metal ions concentration, HQ-bentonite mass, and temperature were tested. Sorption experiments were expressed by Freundlich and Langmuir isotherms and the sorption results demonstrated that the sorption of uranium and thorium onto HQ-bentonite correlated better with the Langmuir isotherm than the Freundlich isotherm. Kinetics studies showed that the sorption followed the pseudo-second-order kinetic model. Thermodynamic parameters such as ΔH°, ΔS°, and ΔG° indicated that the sorption of uranium and thorium onto HQ-bentonite was endothermic, feasible, spontaneous, and physical in nature. The maximum adsorption capacities of HQ-bentonite were calculated from the Langmuir isotherm at 303 K and were found to be 63.90 and 65.44 for U(VI) and Th(IV) metal ions, respectively.

scholarly journals Use of Aluminosilicate Residue from Insulators of High Voltage Transformers for the Adsorption of Basic Dyes

2021 ◽  
Author(s):  
Fernando Murga ◽  
José de Campos ◽  
Roberta Signini
Keyword(s):  
High Voltage ◽  
Physical Adsorption ◽  
Fluorescence Analysis ◽  
Point Of Zero Charge ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Solution Ph ◽  
X Ray ◽  
Basic Dyes ◽  
Order Kinetic Model

In this study, an aluminosilicate residue from insulators of high voltage transformers was used for the adsorption of basic dyes. The absorbent was characterized by X-ray fluorescence analysis, X-ray diffraction analysis, scanning electron microscopy, multimolecular adsorption theory (Branauer-Emmet-Teller (BET)) and determination of the point of zero charge (pHPZC). The effect of solution pH and adsorbent mass, the kinetic and thermodynamic behavior at different temperatures and the application of non-linear isotherm models of Langmuir, Freundlich, Temkin and Dubinin-Radushevich were investigated. The pHPZC value for the aluminosilicate was 3.7. The best conditions for adsorption of methylene blue and crystal violet dyes were pH 8.0 and adsorbent mass of 1100 mg in 25 mL. The best fit for the experimental data was obtained applying the pseudo-second-order kinetic model, with an equilibrium time of 480 to 720 min, and the activation energy suggests a physical adsorption mechanism. Isothermal parameters suggest a heterogeneous, favorable and predominantly physical surface adsorption. The thermodynamic studies indicated that the adsorption process is not spontaneous and is exothermic and the Gibbs energy values (ΔGº) suggest physisorption.

scholarly journals Adsorptive removal of P(V) and Cr(VI) by calcined Zn-Al-Fe ternary LDHs

2021 ◽  
Author(s):  
Nacera Rezak ◽  
Abdellah Bahmani ◽  
Nourredine Bettahar
Keyword(s):  
Aqueous Media ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Scanning Calorimetry ◽  
Solution Ph ◽  
X Ray ◽  
Adsorption Processes ◽  
Order Kinetic Model ◽  
Langmuir Isotherm Model ◽  
Double Hydroxides

Abstract The present study deals with the preparation and structural and adsorbent characterization of the ternary layered double hydroxides (LDHs; ZFA-HT) with molar ratio Zn2+/Al3+/Fe3+ = 2/0.5/0.5 and its product calcined (ZFA-350) at 350 °C, which is examined for the removal of phosphate P(V) and chromate Cr(VI) from aqueous media. The as-obtained materials are characterized by X-ray diffraction (XRD), Fourier-transform infrared (FT-IR), thermogravimetric analysis-differential scanning calorimetry (TGA–DSC), scanning electron microscopy-X-ray energy dispersion (SEM-EDX) and Brunauer–Emmett–Teller (BET). Structural characterizations show that the LDHs is successfully synthesized and its calcined product is a mixed oxide. Batch sorption studies are conducted to investigate the effects of various experimental parameters such as contact time, solution pH, adsorbent amount, initial P(V) or Cr(VI) concentration and temperature. The isotherms, kinetics and thermodynamic parameters of adsorption of phosphate and chromium are studied. The adsorption processes are well described by the pseudo-second-order kinetic model than the other models examined. The adsorption isotherms data fit best to the Langmuir isotherm model instead of Freundlich and Dubinin–Radushkevich models. The maximum monolayer adsorption capacity of ZFA-350 was found to be 140.85 mg/g for P(V) and 52.63 mg/g for Cr(VI). The positive ΔH and ΔS and negative ΔG values reveal that the P(V) and Cr(VI) sorption onto ZFA-350 is endothermic, irreversible and spontaneous in nature.

scholarly journals Rapid Adsorption Removal of Triclosan and p-chloro-m-xylenol In Water By Nitrogen Doped Magnetic Porous Carbon

2021 ◽  
Author(s):  
Qiuxing Li ◽  
Li Huang ◽  
Paijin Zhu ◽  
Min Zhong ◽  
Shuxia Xu
Keyword(s):  
Adsorption Capacity ◽  
Porous Carbon ◽  
Photoelectron Spectroscopy ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
One Pot ◽  
X Ray ◽  
Order Kinetic Model ◽  
Endothermic Process ◽  
The One

Abstract Contamination of water resources with organic substances like phenolic fungicides is undesirable due to the improvement of living standards, huge production and consumption of daily chemicals, and an increase in the population. In this study, ZIF-67(Co) was synthesized using the “one pot method”, and the Co-magnetic porous carbon (Co-NPC) was prepared by ZIF-67 (Co) carbonization in an atmosphere of N2. The materials were tested using a X-ray diffractometer (XRD), scanning electron microscope (SEM), infrared spectroscopy (IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), N2 adsorption-desorption and magnetization analysis. These methods indicated that the Co-NPC was successfully prepared. With the original morphology of ZIF-67 (Co) crystal, the Co-NPC also has good porosity, magnetic properties and a large specific surface area. In water, Co-NPC-800 has a good adsorption capacity for triclosan (TCS) and p-chloro-m-xylenol (PCMX), which are kinds of aromatic fungicides. The adsorption of Co-NPC-800 on both reached equilibrium within 3 min, which is in accordance with the quasi-second-order kinetic model. At 298 K, the maximum adsorption capacity of Co-NPC-800 for TCS and PCMX was 163 and 39 mg·g-1, respectively. The adsorption of TCS and PCMX by Co-NPC-800 is a spontaneous endothermic process with reduced entropy. The combination of Co-NPC-800 and phenols come from multiple action of electrostatic, π-π and hydrogen bond effects. Moreover, Co-NPC-800 can be regenerated through simple washing and can be reused several times. Therefore, Co-NPC-800 has great potential to be applied across sewage treatments and other environmental fields.

Phosphorus removal from aqueous solution using a novel granular material developed from building waste

2017 ◽  
Vol 75 (6) ◽  
pp. 1500-1511 ◽  
Author(s):  
Shengjiong Yang ◽  
Pengkang Jin ◽  
Xiaochang C. Wang ◽  
Qionghua Zhang ◽  
Xiaotian Chen
Keyword(s):  
Granular Material ◽  
Chemical Precipitation ◽  
Phosphate Removal ◽  
Precipitation Process ◽  
Order Kinetic ◽  
Solution Ph ◽  
Experimental Conditions ◽  
Removal Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

In this study, a granular material (GM) developed from building waste was used for phosphate removal from phosphorus-containing wastewater. Batch experiments were executed to investigate the phosphate removal capacity of this material. The mechanism of removal proved to be a chemical precipitation process. The characteristics of the material and resulting precipitates, the kinetics of the precipitation and Ca2+ liberation processes, and the effects of dosage and pH were investigated. The phosphate precipitation and Ca2+ liberation processes were both well described by a pseudo-second-order kinetic model. A maximum precipitation capacity of 0.51 ± 0.06 mg g−1 and a liberation capacity of 6.79 ± 0.77 mg g−1 were measured under the experimental conditions. The processes reached equilibrium in 60 min. The initial solution pH strongly affected phosphate removal under extreme conditions (pH <4 and pH >10). The precipitates comprised hydroxyapatite and brushite. This novel GM can be considered a promising material for phosphate removal from wastewater.

scholarly journals Municipal Leachate Treatment by Fenton Process: Effect of Some Variable and Kinetics

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Mohammad Ahmadian ◽  
Sohyla Reshadat ◽  
Nader Yousefi ◽  
Seyed Hamed Mirhossieni ◽  
Mohammad Reza Zare ◽  
...  
Keyword(s):  
Reaction Time ◽  
Color Removal ◽  
Molar Ratio ◽  
Order Kinetic ◽  
Fenton Process ◽  
Solution Ph ◽  
Leachate Treatment ◽  
First Order ◽  
Order Kinetic Model ◽  
Better Than

Due to complex composition of leachate, the comprehensive leachate treatment methods have been not demonstrated. Moreover, the improper management of leachate can lead to many environmental problems. The aim of this study was application of Fenton process for decreasing the major pollutants of landfill leachate on Kermanshah city. The leachate was collected from Kermanshah landfill site and treated by Fenton process. The effect of various parameters including solution pH, Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time was investigated. The result showed that with increasing Fe2+and H2O2dosage, Fe2+/H2O2molar ratio, and reaction time, the COD, TOC, TSS, and color removal increased. The maximum COD, TOC, TSS, and color removal were obtained at low pH (pH: 3). The kinetic data were analyzed in term of zero-order, first-order, and second-order expressions. First-order kinetic model described the removal of COD, TOC, TSS, and color from leachate better than two other kinetic models. In spite of extremely difficulty of leachate treatment, the previous results seem rather encouraging on the application of Fenton’s oxidation.

Preparation of Novel Ag–Si–TiO2 Composite and Research on Its Photocatalytic Degradation of Formaldehyde

2021 ◽  
Vol 13 (3) ◽  
pp. 371-380
Author(s):  
Yongjun Wu ◽  
Nina Xie ◽  
Lu Yu
Keyword(s):  
Photoelectron Spectroscopy ◽  
Removal Rate ◽  
Sol Gel ◽  
Catalytic Performance ◽  
Formaldehyde Concentration ◽  
Order Kinetic ◽  
Solution Ph ◽  
Visible Absorption ◽  
X Ray ◽  
Co Doped

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.

scholarly journals Optimization of process parameters for heavy metals biosorption onto mustard waste biomass

2016 ◽  
Vol 14 (1) ◽  
pp. 175-187 ◽  
Author(s):  
Lăcrămioara (Negrilă) Nemeş ◽  
Laura Bulgariu
Keyword(s):  
Heavy Metals ◽  
Aqueous Media ◽  
Order Kinetic ◽  
Waste Biomass ◽  
Solution Ph ◽  
Biosorption Process ◽  
Optimization Of Process Parameters ◽  
Removal Of Heavy Metals ◽  
Equilibrium Data ◽  
Order Kinetic Model

AbstractMustard waste biomass was tested as a biosorbent for the removal of Pb(II), Zn(II) and Cd(II) from aqueous solution. This strategy may be a sustainable option for the utilization of such wastes. The influence of the most important operating parameters of the biosorption process was analyzed in batch experiments, and optimal conditions were found to include initial solution pH 5.5, 5.0 g biosorbent/L, 2 hours of contact time and high temperature. Kinetics analyses show that the maximum of biosorption was quickly reached and could be described by a pseudo-second order kinetic model. The equilibrium data were well fitted by the Langmuir model, and the highest values of maximum biosorption capacity were obtained with Pb(II), followed by Zn(II) and Cd(II). The thermodynamic parameters of the biosorption process (ΔG, ΔH and ΔS) were also evaluated from isotherms. The results of this study suggest that mustard waste biomass can be used for the removal of heavy metals from aqueous media.

scholarly journals Preparation of bio-absorbents by modifying licorice residue via chemical methods and removal of copper ions from wastewater

2021 ◽  
Author(s):  
Xiaochun Yin ◽  
Nadi Zhang ◽  
Meixia Du ◽  
Hai Zhu ◽  
Ting Ke
Keyword(s):  
Adsorption Capacity ◽  
Copper Ions ◽  
Order Kinetic ◽  
Solution Ph ◽  
Chemical Methods ◽  
Simple Strategy ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Surface Active ◽  
Adsorption Desorption

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.

Swelling and kinetic investigations of basic blue-3 sorption by polyacrylamide/Gum Arabic hybrid hydrogel in aqueous medium

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Uzma ◽  
Sultan Alam ◽  
Hanif Subhan ◽  
Luqman Ali Shah ◽  
Noor Saeed Khattak
Keyword(s):  
Thermo Gravimetric Analysis ◽  
Gum Arabic ◽  
Composite Hydrogel ◽  
Gravimetric Analysis ◽  
Order Kinetic ◽  
One Pot ◽  
Hybrid Hydrogel ◽  
Aquatic Life ◽  
Hybrid Sorbent ◽  
Order Kinetic Model

Abstract Removal of noxious dyes from waste water is highly desirable for the safety of humans, aquatic life and natural environment. The issue was addressed in the present work by one pot fabrication of polyacrylamide/Gum Arabic (pAAm/GA) composite hydrogel which was applied as sorbent for basic blue-3 (BB3) eradication. The synthesis of the material was confirmed by scanning electron microscopy (SEM), Fourier Transformed Infrared (FTIR) spectroscopy and thermo gravimetric analysis (TGA). Besides, the same techniques also evidenced BB3 uptake by the hydrogel. In distilled water, the swelling capacities of the hydrogel was investigated at pH 7 and the nature of water diffusion into the hydrogel was probed from the resultant data. The composite hydrogel reached equilibrium point in 24 h after which no appreciable water absorption occurred. The adsorption of BB3 by the hybrid material was comprehensively investigated which involved the effect of contact time, temperature and pH on the sorption capacity of the hybrid sorbent. The obtained data fitted well into pseudo second order kinetic model and the adsorption took place in three consecutive kinetic phases. Moreover, sorption thermodynamics revealed non spontaneous and endothermic nature of BB3 sorption accompanied with increase in degree of order.

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