Synthesis of PANI@ZnO Hybrid Material and Evaluations in Adsorption of Congo Red and Methylene Blue Dyes: Structural Characterization and Adsorption Performance

Abstract In this research, a simple oxidation chemical process was applied for the synthesis of novel PANI@ZnO nanocomposite. The prepared nanocomposites were characterized by XPS, XRD, FTIR, SEM, TGA and N2 adsorption-desorption isotherms. Thereby, PANI@ZnO highest SBET values (about 40.84 m2.g− 1), total mesoporous volume (about 3.214 cm3.g− 1) and average pore size (about 46.12 nm). Afterwards, the prepared nanomaterial was applied as novel nanoadsorbent for the adsorption of Congo Red (CR) and Methylene Blue (MB) dyes from aqueous solutions at 298 K and pH 5.0. Besides, the pseudo-second-order model was obtained the best for the adsorption of both dyes. In the case of isotherm models, the Freundlich model showed the best fit. After removal, the spent adsorbent was regenerated. With the regeneration repeated five cycles, the PANI@ZnO regeneration efficiency remained at a very adequate level.

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Recovery of Pd(II) from Aqueous Solution by Polyethylenimine-Crosslinked Chitin Biosorbent

Coatings ◽

10.3390/coatings11050593 ◽

2021 ◽

Vol 11 (5) ◽

pp. 593

Author(s):

Zhuo Wang ◽

Su Bin Kang ◽

Sung Wook Won

Keyword(s):

Adsorption Equilibrium ◽

Average Pore Size ◽

Fixed Bed ◽

Sem Analysis ◽

Order Model ◽

Average Pore ◽

Fixed Bed Column ◽

Practical Applications ◽

Pseudo Second Order ◽

Adsorption Desorption

This study reports the recovery of Pd(II) from acid solution by a polyethylenimine (PEI)-crosslinked chitin (PEI-chitin) biosorbent. FE-SEM analysis demonstrated that there are many slot-like pores on PEI-chitin. The N2 adsorption–desorption experiment revealed that the average pore size was 47.12 nm. Elemental analysis verified the successful crosslinking of PEI with raw chitin. The Langmuir model better explained the isotherm experimental data and the theoretical maximum Pd(II) uptake was 57.1 mg/g. The adsorption kinetic data were better described by the pseudo-second-order model and the adsorption equilibrium was achieved within 30 min for all initial Pd(II) concentrations of 50–200 mg/L. In the fixed-bed column, the adsorption of Pd(II) on PEI-chitin showed a slow breakthrough and a fast saturation performance. The desorption experiments achieved a concentration factor of 8.4 ± 0.4; in addition, the adsorption–desorption cycles in the fixed-bed column were performed up to three times, consequently confirming the good reusability of PEI-chitin for Pd(II) recovery. Therefore, the PEI-chitin can be used as a promising biosorbent for the recovery of Pd(II) in practical applications.

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Removal of Pb2+ ions from aqueous solution by P(HEA/IA) hydrogels

Hemijska industrija ◽

10.2298/hemind151225006a ◽

2016 ◽

Vol 70 (6) ◽

pp. 695-705 ◽

Cited By ~ 3

Author(s):

Katarina Antic ◽

Marija Babic ◽

Jovana Vukovic ◽

Antonije Onjia ◽

Jovanka Filipovic ◽

...

Keyword(s):

Significant Loss ◽

Isotherm Models ◽

Order Model ◽

Solution Ph ◽

Sorption Data ◽

Maximum Sorption ◽

Pseudo Second Order ◽

Adsorption Desorption ◽

Best Fit ◽

Sorbent Weight

A series of poly(2-hydroxyethyl acrylate-co-itaconic acid), P(HEA/IA), hydrogels with different HEA/IA ratio, were synthesized using free radical crosslinking/copolymerization and investigated as sorbents for Pb2+ ions from aqueous solutions. Hydrogels were characterized using DMA, FTIR, DSC, SEM and AFM. The adsorption was found to be highly dependent on hydrogel composition, solution pH, sorbent weight, ionic strength and contact time. Five isotherm models, Langmuir, Freundlich, Redlich-Peterson, Temkin and Dubinin-Radushkevich, were applied to the sorption data. The best fit was obtained with Redlich-Peterson isotherm. The separation factor, RL, value indicated favorable sorption for Pb2+ ions. The maximum sorption capacities were 392.2 and 409.8 mg/g for P(HEA/2IA) and P(HEA/10IA), respectively. Kinetic data showed best fit with pseudo-second-order model. Thermodynamic studies revealed that the reaction was exothermic and proceeds with a decrease in entropy. Moreover, P(HEA/IA) hydrogel showed the most pronounced sorption toward Pb2+ ions from environment containing Cu2+, Zn2+, Cd2+, Ni2+ and Co2+ ions. Sorption/desorption experiments, showed that the P(HEA/IA) hydrogels could be reused without significant loss of the initial properties even after three adsorption-desorption cycles.

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Synthesis, Characterization and Adsorption Studies of a Graphene Oxide/Polyacrylic Acid Nanocomposite Hydrogel

NeuroQuantology ◽

10.14704/nq.2021.19.9.nq21136 ◽

2021 ◽

Vol 19 (9) ◽

pp. 46-54

Author(s):

Makarim A. Mahdi ◽

Aymen A.R. Jawad ◽

Aseel M. Aljeboree ◽

Layth S. Jasim ◽

Ayad F. Alkaim

Keyword(s):

Industrial Effluents ◽

Langmuir Model ◽

Isotherm Models ◽

Nanocomposite Hydrogel ◽

Adsorption System ◽

Order Model ◽

Solution Ph ◽

Freundlich Model ◽

Dye Sorption ◽

Pseudo Second Order

The AAc/GO nanocomposite hydrogel was successfully employed as a polymeric Nano sorbent of the removal efficiency of M G dye from the model. The complication of the mechanism of the adsorption system was completely exposed by examining how solution pH affects adsorption, Ionic strength isotherm models, kinetic models, and thermodynamics. The adsorption of the MG dye was greatly dependent on the solution pH. The Freundlich model has been demonstrated to be the most accurate in describing the MG dye sorption, whilst the Langmuir model was shown to be the least accurate. Additionally, these integrated mechanisms fit nicely within the framework of a pseudo-second-order model. Additionally, the contact time at equilibrium short (ten minutes) required to MG removes demonstrates the AAc/GO nanocomposite hydrogel can be considered an efficient and potentially useful adsorbent for MG removal from industrial effluents.

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Tea Stem as a Sorbent for Removal of Methylene Blue from Aqueous Phase

Advances in Materials Science and Engineering ◽

10.1155/2019/9723763 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 3

Author(s):

Tzan-Chain Lee ◽

Shumao Wang ◽

Zonggui Huang ◽

Zhongxing Mo ◽

Gangxing Wang ◽

...

Keyword(s):

Methylene Blue ◽

Ionic Strength ◽

Aqueous Phase ◽

Removal Efficiency ◽

Adsorption Mechanism ◽

Second Order ◽

Isotherm Models ◽

Order Model ◽

Pseudo Second Order ◽

Second Order Model

The potentiality of tea stem for the adsorption of methylene blue (MB) from aqueous phase was investigated. A series of operating factors, including the initial MB concentration, contact time, pH of solution, dose of tea stem, and ionic strength of solution, were conducted to understand the effect of adsorption of MB onto tea stem. Adsorption isotherm, kinetic models, thermodynamic investigation, and regenerability of tea stem were systematically investigated in this study. The experiment results revealed that the removal efficiency decreased with MB concentration and the equilibrium time of adsorption at different initial MB concentrations was approximately at 60 min. The appropriate dose of tea stem powder was found to be 4 g/L. The pHzpc of tea stem was evaluated and was observed to be 6.0 ± 0.2. The removal efficiency increased with pH ranging from 3.0 to 5.0 and remained constantly at the pH range of 5.0–11.0. The pH affected the adsorption because of the repellent power between H+ and dye cation. The ionic strength was found to have a negligible effect on the adsorption. The Langmuir and Temkin isotherm models were found to be the best isotherm models to elucidate the adsorption mechanism between MB and tea stem powder. The maximum adsorption capacity of 103.09 mg/g derived from the Langmuir model was much close to the experimental result. From the kinetic analysis, the pseudo-second-order model was found to be the suitable model to describe the adsorption behavior. The calculated adsorption capacities at different temperatures derived from the pseudo-second-order model ranging from 68.91 to 69.8 mg/g were well close to the experimental data. The intraparticle diffusion of MB molecules into pore structures of tea stem powder is the rate-limiting step for the adsorption process in this study. Evaluation of thermodynamic parameters including changes in enthalpy, entropy, and Gibb’s free energy indicated the adsorption mechanism between MB and tea stem powder was a spontaneous and exothermic process. The regeneration/adsorption experiments indicated that the tea stem powder efficiently remained more than 97% after five cycles using NaOH as a desorbing agent and thus be used for many times. On the basis of experimental results obtained, it is concluded that the tea stem has a considerable potential as a low-cost sorbent for removing MB from the aqueous phase.

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Preparation of cellulose/diatomite composite material and its adsorption characteristics and kinetics

BioResources ◽

10.15376/biores.15.4.8728-8743 ◽

2020 ◽

Vol 15 (4) ◽

pp. 8728-8743

Author(s):

Hongfang Zhou ◽

Liang Zhao ◽

Runzhou Huang ◽

Yuhang Yang ◽

Zhengle Que ◽

...

Keyword(s):

Average Pore Size ◽

Total Pore Volume ◽

Isotherm Models ◽

Average Pore ◽

Ph Values ◽

Preparation Conditions ◽

Composite Adsorbents ◽

Pseudo Second Order ◽

Holding Temperature ◽

Mb Adsorption

The optimal preparation conditions for cellulose/diatomite composite adsorbents (CDAs) were determined to be a diatomite concentration of 40 wt%, a holding temperature of 700 °C, and a holding time of 30 min. Meanwhile, the yield of CDAs was 70.6%, and the methylene blue (MB) adsorption value was 191.8 mg/g. The specific surface area, total pore volume, and average pore size of the CDAs were 489 m2/g, 0.372 cm3/g, and 3.04 nm, respectively. It was inferred that the diatomite was cross-linked with the cellulose carbon to form some micropores. Greater MB initial concentrations and pH values improved the adsorption on the CDAs. The MB adsorption behavior of the CDAs was described very well by the pseudo-second-order model. The isotherm models showed relatively high adsorption of MB.

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Brasil nut mesocarp (Bertholletia excels) as a Biomass Source for Activated Carbon Production: Correlation Between Thermal Treatment and Adsorption Performance

Biointerface Research in Applied Chemistry ◽

10.33263/briac124.45844596 ◽

2021 ◽

Vol 12 (4) ◽

pp. 4584-4596

Keyword(s):

Activated Carbon ◽

Maximum Adsorption Capacity ◽

Brazil Nut ◽

Order Model ◽

X Ray ◽

Adsorption Performance ◽

Carbon Production ◽

Pseudo Second Order ◽

Adsorption Desorption ◽

Best Fit

The activated carbon investigated in this work was produced from the extractive residues of Brazil nut processing, more specifically from the mesocarp of the Amazonian fruit. The process was performed by muffle pyrolysis, with ZnCl2 impregnation, at 400 and 500 °C. All samples were characterized by X-ray diffractometry, thermogravimetry, CHNS elemental analysis, scanning electron microscopy, and adsorption/desorption of N2. The results were promissory, with 99% removal of methylene blue for the CA25 material, which has a surface area of 1236 m2 g-1, much higher than commercial coal (CAC, 618 m2 g-1). The adsorption kinetics best fit the pseudo-second-order model for all materials. The maximum adsorption capacity obtained was 195.3 mg g-1. Therefore, the extractive residue of Brazil nut has excellent potential for the development of activated carbon, which can be used effectively to mediate environmental contamination in a given aqueous medium.

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LDH Nanocubes Synthesized with Zeolite Templates and Their High Performance as Adsorbents

Nanomaterials ◽

10.3390/nano11123315 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3315

Author(s):

Moftah Essa Elkartehi ◽

Rehab Mahmoud ◽

Nabila Shehata ◽

Ahmed Farghali ◽

Shimaa Gamil ◽

...

Keyword(s):

Electron Microscopy ◽

Average Pore Size ◽

Second Order ◽

Polluted Water ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Solution Ph ◽

Average Pore ◽

X Ray ◽

Pseudo Second Order

In this work, the efficiency of the adsorptive removal of the organic cationic dye methylene blue (MB) from polluted water was examined using three materials: natural clay (zeolite), Zn-Fe layered double hydroxide (LDH), and zeolite/LDH composite. These materials were characterized via X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, high-resolution transmission electron microscopy (HRTEM), energy dispersive X-ray (EDX) diffraction (XRF), low-temperature N2 adsorption, pore volume and average pore size distribution and field emission scanning electron microscopy (FE-SEM). The properties of the applied nanomaterials regarding the adsorption of MB were investigated by determining various experimental parameters, such as the contact time, initial dye concentration, and solution pH. In addition, the adsorption isotherm model was estimated using the Langmuir, Freundlich, and Langmuir–Freundlich isotherm models. The Langmuir model was the best-fitting for all applied nanomaterials. In addition, the kinetics were analyzed by using pseudo-first-order, pseudo-second-order, and intraparticle diffusion models, and the pseudo-second-order model was an apparent fit for all three applied nanomaterials. The maximum Adsorption capacity toward MB obtained from the materials was in the order zeolite/LDH composite > zeolites > Zn-Fe LDH. Thus, the zeolite/LDH composite is an excellent adsorbent for the removal of MB from polluted water.

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Adsorption of crystal violet with diatomite earth&carbon by a modification of hydrothermal carbonization process

Water Science & Technology ◽

10.2166/wst.2015.625 ◽

2015 ◽

Vol 73 (6) ◽

pp. 1463-1471 ◽

Cited By ~ 1

Author(s):

Zhang Yanzhuo ◽

Li Jun ◽

Chen Guanghui ◽

Bian Wei ◽

Lu Yun ◽

...

Keyword(s):

Crystal Violet ◽

Adsorption Process ◽

Hydrothermal Carbonization ◽

Dyeing Wastewater ◽

Order Model ◽

Average Pore ◽

Printing And Dyeing Wastewater ◽

Equilibrium Data ◽

Pseudo Second Order ◽

Adsorption Desorption

The high colority and difficulty of decolorization are the most important tasks on printing and dyeing wastewater. This study investigates the ability of diatomite earth&carbon (DE&C) as an adsorbent to removal crystal violet (CV) from aqueous solutions. Fourier transform infrared spectroscopy results indicate the importance of functional groups during the adsorption of CV. The obtained N2 adsorption–desorption isotherm values accord with well IUPAC type II. Our calculations determined a surface area of 73.15 m2 g−1 for DE&C and an average pore diameter of 10.56 nm. Equilibrium data of the adsorption process fitted very well to the Langmuir model (R2 > 0.99). The results of kinetics study showed that the pseudo-second-order model fitted to the experimental data well. The thermodynamic parameters were also evaluated. ΔH° <0, ΔS° > 0 and ΔG° < 0 demonstrated that the adsorption process was spontaneous and exothermic for dye. Furthermore the positive value of ΔS° reflected good affinity of the CV dye.

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Highly Effective Adsorption of Caffeine by a Novel Activated Carbon Prepared From Coconut Leaf

10.21203/rs.3.rs-901559/v1 ◽

2021 ◽

Author(s):

Elvio N. Oliveira ◽

Alex T. Meneses ◽

Samara F. de Melo ◽

Franciele M. R. Dias ◽

Maisa T. B. Perazzini ◽

...

Keyword(s):

Activated Carbon ◽

Activated Carbons ◽

Physical Adsorption ◽

Average Pore Size ◽

Kinetic Studies ◽

Amorphous Structure ◽

Operating Conditions ◽

Average Pore ◽

Pseudo Second Order ◽

Adsorption Desorption

Abstract The disposal of coconut wastes is costly and damaging to the environment, but its uses are advantageous activated carbons production. Coconut leaves waste were used for activated carbon production by pyrolysis at 500º C and activation with potassium carbonate. The activated carbon was used for caffeine removal from aqueous solution. The coconut leaves activated carbon showed a predominantly amorphous structure from X-ray diffraction analysis and a pH at the zero charge point of 7.9. From the N2 adsorption/desorption method, the adsorbent showed a predominance of mesopores, with average pore size of 45.48 ηm and a surface area of 678.03 m2/g. From kinetic studies the data followed the pseudo-second order, where the intraparticle diffusion can be neglected. The adsorption isotherms were satisfactorily adjusted for the Redlich-Peterson model and a type curve L was identified. The thermodynamic parameters showed that adsorption occurred spontaneously, was exothermic and governed by physical adsorption. The artificial neural networks developed were capable of predicting both kinetics and equilibrium adsorption data under different operating conditions and was comparable to the traditional models available in literature in the training experiments, encouraging its use for data generalization when an efficient dataset is used. In conclusion, coconut leaves waste showed to be a promising feedstock to produce activated carbon aiming caffeine removal from water and wastewater.

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A comparative study on Fe(III)-chitosan and Fe(III)-chitosan-CTAB composites for As(V) removal from water: preparation, characterization and reaction mechanism

10.21203/rs.3.rs-1261066/v1 ◽

2022 ◽

Author(s):

Changjin Jiang ◽

Ting Zhang ◽

Shuhui Li ◽

Zhaoguang Yang

Keyword(s):

Order Model ◽

Freundlich Model ◽

Structure And Property ◽

Adsorption Capacities ◽

Wide Range ◽

Naoh Solution ◽

Pseudo Second Order ◽

Ft Ir ◽

Initial Adsorption ◽

Adsorption Desorption

Abstract Fe(III)-chitosan and Fe(III)-chitosan-CTAB composites were prepared using an ionotropic gelation method. Various techniques were used to analyze the morphology, structure, and property of the adsorbents, including SEM, EDS, FT-IR, XPS, and zeta potential. Compared with Fe(III)-chitosan, Fe(III)-chitosan-CTAB was more effective for As(V) adsorption at a wide range of pH (3–8). The adsorption of As(V) onto Fe(III)-chitosan and Fe(III)-chitosan-CTAB could reach equilibrium in 20 min, and their maximum adsorption capacities were 33.85 and 31.69 mg g‒1, respectively. The adsorption kinetics was best described by the pseudo-second-order model (R2=0.998 and 0.992), whereas the adsorption isotherms was fitted well by the Freundlich model (R2=0.963 and 0.987). The presence of H2PO4− significantly inhibited the adsorption of As(V) onto Fe(III)-chitosan and Fe(III)-chitosan-CTAB, and humic acid also led to a slight decrease in As(V) adsorption by Fe(III)-chitosan-CTAB. Over 94% of As(V) at the initial concentration of no more than 5 mg L−1 was removed from real water by the two adsorbents. 1% (w/v) NaOH solution was determined to be the most suitable desorption agent. Fe(III)-chitosan and Fe(III)-chitosan-CTAB still maintained their initial adsorption capacities after five adsorption-desorption cycles. Based on different characterization results, both electrostatic attraction and surface complexation mechanisms played important roles in As(V) adsorption on Fe(III)-chitosan and Fe(III)-chitosan-CTAB.

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