New Cellulose based pH-Sensitive Hydrogel for Highly Efficient Dyes Removal in Water Treatment: Kinetic, Thermodynamic, Theoretical and Computational Studies

Abstract In this paper, a new green pH-sensitive cellulose based hydrogel (swelling rate ~ 1005 %) was successfully elaborated. However, the new EDTA crosslinked HEC was investigated as adsorbent materiel, which it showed high removal efficiency (~2000 mg.g-1) to aquatic micropollutants, especially methylene blue as cationic dyes model. The synthesis of HEC-EDTA at high advanced crosslinking degree (up to 92 %) that confirmed using structural analyzes (FTIR and 13C CP/MAS-NMR), was cried out using DAEDT and DMAP as acyl transfer agent, where the lamellar morphology (2D- microstructure) was highly suggested basing on the average functionality of the reaction system. The kinetic study showed that the adsorption process was better described by pseudo-second-order kinetic, where the thermodynamic parameters exhibited a negative effect of temperature indicating a physical adsorption process. In addition, the adsorption capacity was studied according to the experimental conditions (pH, contact time, concentration, etc.), and the Freundlich model revealed a strong correlation to the experimental results indicating an energetic heterogeneity of the surface active sites. In the other hand, molecular dynamics (MD) simulations were conducted and optimized using COMPASS II, where the results showed a good agreement with the experiment, and that basing on the intermolecular Non-covalent interaction, molecular structure and cluster configurations.

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Preparation and Chemical Modification of Rice Husk Char for the Removal of a Toxic Dye (Orange G) from Aqueous Medium

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2018-1190 ◽

2019 ◽

Vol 233 (3) ◽

pp. 375-392 ◽

Cited By ~ 3

Author(s):

Abdul Malik ◽

Abbas Khan ◽

Muhammad Humayun

Keyword(s):

Rice Husk ◽

Adsorption Process ◽

Aqueous Media ◽

Effect Of Temperature ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

Experimental Conditions ◽

Orange G ◽

Adsorbent Dose

Abstract The rice husk char (RHC) was prepared by keeping a known amount of the rice husk in furnace at 400°C. The product was modified with KOH and labeled as KOH modified rice husk char (KMRHC) which was used as an adsorbent for the removal of toxic dye, Orange G (OG) from aqueous media. Variation in the experimental conditions (agitation time, dye concentration, adsorbent dose, pH and temperature) play significant role in the adsorption process. The maximum adsorption capacity of OG on KMRHC was investigated as 38.8 mg/g at pH=4 using initial dye concentrations of 80 mg/L containing 2 g/L of the adsorbent dose with agitation speed of 250 rpm at 303 K. The % adsorption of dye was inspected as 96%. Thermodynamics studies of the adsorption of OG on KMRHC indicated that the value of ΔG and ΔH were negative which revealed that the adsorption process is exothermic and spontaneous process. The negative value of ΔS suggested that randomness decreases at the interface of adsorbent–adsorbate during the adsorption process. The kinetics study indicated that the experimental data of the adsorption process best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was inspected that data follows all the three isotherm models (R2>0.91). However, the values of correlation coefficients (R2) indicated that the data is best fit to the Langmuir isotherm model (R2>0.99) which suggest for chemi-sorption process. The effect of temperature (303–343 K) shows that by varying the temperature the adsorption process is significantly affected. The general trend indicates that adsorption efficiency is higher at lower temperature as compared to higher temperature. This trend also suggests that the adsorption coefficient (K), rate of adsorption, and hence the spontaneity of adsorption process also decreases with raising the temperature.

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Study on Adsorption Properties of Modified Corn Cob Activated Carbon for Mercury Ion

Energies ◽

10.3390/en14154483 ◽

2021 ◽

Vol 14 (15) ◽

pp. 4483

Author(s):

Yuyingnan Liu ◽

Xinrui Xu ◽

Bin Qu ◽

Xiaofeng Liu ◽

Weiming Yi ◽

...

Keyword(s):

Activated Carbon ◽

Photoelectron Spectroscopy ◽

Adsorption Process ◽

Physical Adsorption ◽

Raw Material ◽

Order Kinetic ◽

Mercury Ions ◽

Corn Cob ◽

Adsorption Time ◽

X Ray

In this study, corn cob was used as raw material and modified methods employing KOH and KMnO4 were used to prepare activated carbon with high adsorption capacity for mercury ions. Experiments on the effects of different influencing factors on the adsorption of mercury ions were undertaken. The results showed that when modified with KOH, the optimal adsorption time was 120 min, the optimum pH was 4; when modified with KMnO4, the optimal adsorption time was 60 min, the optimal pH was 3, and the optimal amount of adsorbent and the initial concentration were both 0.40 g/L and 100 mg/L under both modified conditions. The adsorption process conforms to the pseudo-second-order kinetic model and Langmuir model. Scanning electron microscopy and energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS) and Zeta potential characterization results showed that the adsorption process is mainly physical adsorption, surface complexation and ion exchange.

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Eco-Friendly Sustainable Fluorescent Carbon Dots for the Adsorption of Heavy Metal Ions in Aqueous Environment

Nanomaterials ◽

10.3390/nano10020315 ◽

2020 ◽

Vol 10 (2) ◽

pp. 315 ◽

Cited By ~ 3

Author(s):

Musa Yahaya Pudza ◽

Zurina Zainal Abidin ◽

Suraya Abdul Rashid ◽

Faizah Md Yasin ◽

A. S. M. Noor ◽

...

Keyword(s):

Heavy Metal ◽

Metal Ions ◽

Carbon Dots ◽

Heavy Metal Ions ◽

Active Sites ◽

Adsorption Process ◽

Coefficient Of Determination ◽

Aqueous Environment ◽

Order Kinetic ◽

Sensing Applications

The materials and substances required for sustainable water treatment by adsorption technique, are still being researched widely by distinguished classes of researchers. Thus, the need to synthesize substances that can effectively clean up pollutants from the environment cannot be overemphasized. So far, materials in bulk forms that are rich in carbon, such as biochar and varieties of activated carbon have been used for various adsorptive purposes. The use of bulk materials for such purposes are not efficient due to minimal surface areas available for adsorption. This study explores the adsorption task at nano dimension using carbon dots (CDs) from tapioca. The properties of carbon structure and its influence on the adsorptive efficacy of carbon nanoparticles were investigated by energy-dispersive spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HrTEM), and atomic force microscopy (AFM). The results implied carbon present in CDs are good adsorbents for effective adsorption of heavy metal ions (lead) with removal efficiency of 80.6% in aqueous environment. The adsorption process as explored by both Langmuir and Freundlich isotherms have proven favorability of the adsorption process. Langmuir form two and three have correlation coefficients R2 at 0.9922 and 0.9912, respectively. The Freundlich isotherm confirms CDs as having defined surface heterogeneity and the exponential distribution of active sites. The adsorption of lead unto CDs obeyed the second order kinetic model with coefficient of determination, R2 of 0.9668 and 0.9996 at an initial lead concentration of 20 mg/L and 100 mg/L, respectively. The findings validated the efficiency of CDs derived from tapioca as an excellent material for further utilization in the environmental fields of wastewater pollution detection and clean up, bio-imaging, and chemical sensing applications.

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Adsorption and recovery of nonylphenol ethoxylate on a crosslinked β-cyclodextrin-carboxymethylcellulose polymer

Water Science & Technology ◽

10.2166/wst.2010.152 ◽

2010 ◽

Vol 61 (9) ◽

pp. 2293-2301 ◽

Cited By ~ 10

Author(s):

Danielle Bonenfant ◽

Patrick Niquette ◽

Murielle Mimeault ◽

Robert Hausler

Keyword(s):

Adsorption Capacity ◽

Atmospheric Pressure ◽

Active Sites ◽

Adsorption Process ◽

Adsorption Equilibrium ◽

Physical Adsorption ◽

Polymer Network ◽

Homogeneous Distribution ◽

Nonylphenol Ethoxylate ◽

Monolayer Coverage

A study of adsorption/recovery of nonylphenol 9 mole ethoxylate (NP9EO) on a crosslinked β-cyclodextrin-carboxymethylcellulose (β-CD-CMC) polymer was carried out by ultraviolet-visible (UV-vis) and Fourier transform infrared (FTIR) spectroscopies. The adsorption was performed in mixtures containing 500 mg of the β-CD-CMC polymer and aqueous NP9EO solutions at concentrations 12–82 mg/L, whereas the recovery of NP9EO was effectuated by shaking the β-CD-CMC polymer loaded with methanol. The assays were made at 25°C and atmospheric pressure under agitation. The results have shown that the adsorption is a rapid process and the β-CD-CMC polymer exhibits a high NP9EO adsorption capacity of 83–92 w% (1.1–6.8 mg NP9EO/g β-CD-CMC polymer) dependent of the initial NP9EO concentration in liquid phase. This adsorption may involve the formation of an inclusion complex β-CD-NP9EO and a physical adsorption in the polymer network. The adsorption equilibrium measurements, which were analyzed using the Langmuir isotherm, have indicated a monolayer coverage and the homogeneous distribution of active sites at the surface of the β-CD-CMC polymer. Moreover, the negative value obtained for the free energy change (−13.2 kJ/mol) has indicated that the adsorption process is spontaneous. In parallel, the β-CD-CMC polymer exhibited a high NP9EO recovery efficiency of 97 w% that may occur through a decrease of binding strength between β-CD-CMC polymer and NP9EO. Together, these results suggest that the β-CD-CMC polymer could constitute a good adsorbent for removing nonylphenol ethoxylates from wastewater due to its high adsorption capacity and non-toxic character of β-CD and CMC to environment.

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Fabrication of PVA/ GO Nanofiber Films by Electrospinning: Application for the Adsorption of Cu2+ and Organic Dyes

10.21203/rs.3.rs-756953/v1 ◽

2021 ◽

Author(s):

Yao He ◽

huafeng tian ◽

Aimin Xiang ◽

Songbai Ma ◽

Duoyuan Yin ◽

...

Keyword(s):

Active Sites ◽

Adsorption Process ◽

Organic Dyes ◽

Physical Adsorption ◽

Molecular Layer ◽

Adsorption Model ◽

Isothermal Adsorption ◽

Nanofiber Film ◽

Adsorption Kinetics And Isotherm ◽

Increasing Temperature

Abstract In recent years, the treatment of water pollution has been a challenging and far-reaching topic. In order to improve the adsorption performance of polyvinyl alcohol nanofibers, a new nano-adsorbent graphene oxide was introduced into them in this work. The introduction of GO greatly increases the adsorption of Cu2+, Methylene blue (MB) and Congo Red (CR). The adsorption kinetics and isotherm analysis of the PVA/GO nanofiber film during the adsorption process showed that the adsorption of Cu2+ and MB by PVA/GO nanofiber film was mainly chemical adsorption, while the adsorption of CR was mainly physical adsorption. The adsorption process of PVA/GO nanofiber film on Cu2+ was in line with the Langmuir isothermal adsorption model, that is, single molecular layer adsorption, the distribution of adsorption active sites was relatively uniform, and the increasing temperature was more conducive to the adsorption of Cu2+.

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The Kinetics and Equilibrium Thermodynamics Study on the Removal of Direct Blue and Titan Yellow Dyes from Aqueous Media by Modified Rice Husk Char

Zeitschrift für Physikalische Chemie ◽

10.1515/zpch-2019-1448 ◽

2020 ◽

Vol 234 (3) ◽

pp. 485-503

Author(s):

Abdul Malik ◽

Abbas Khan ◽

Nasrullah Shah ◽

Muhammad Sufaid Khan

Keyword(s):

Rice Husk ◽

Adsorption Process ◽

Aqueous Media ◽

Isotherm Models ◽

Maximum Adsorption Capacity ◽

Order Kinetic ◽

X Rays ◽

Experimental Conditions ◽

Titan Yellow ◽

Direct Blue

AbstractThe use of indigenous natural materials and their modification toward fruitful application is one of the important subjects. Thermal modification of Rice Husk at 400 oC resulted into Rice Husk Char (RHC) which was chemically modified with KOH and was labeled as KOH Modified Rice Husk Char (KMRHC). Both RHC and KMRHC were characterized by using, Fourier transformed infrared (FTIR), scanning electron microscopy (SEM), energy dispersive X-rays (EDX) and X-ray diffraction (XRD) before and after their use as adsorbents. The prepared material was applied for the removal of toxic dyes, Direct Blue (DB) and Titan Yellow (TY) from aqueous media. The maximum adsorption capacity of DB and TY dyes on KMRHC were inspected as 30.9 mg/g and 28.6 mg/g, respectively at pH 4 using initial dye concentrations of 80 mg/L containing 2500 mg/L of the adsorbent dose with agitation speed of 240 rpm at 303 K. At the same experimental conditions the highest percentage removal of DB and TY on the adsorbent were observed as 96.6% and 89.3%, respectively. Thermodynamics studies of the adsorption of DB and TY dyes on KMRHC inferred for exothermic and spontaneous process. The value of ΔS is negative which suggested that randomness decreases at the interface of adsorbent-adsorbate during the adsorption. The kinetics study indicated that the experimental data of the adsorption process for both dyes, best fits to pseudo-second order kinetic model. The equilibrium data was tested on Langmuir, Freundlich and Temkin adsorption isotherm models. It was observed that the data are best fit to the Langmuir isotherm model (R2 > 0.99), which suggested that the adsorption process is dominated by chemisorption approach. The overall results suggest that various parameters of the adsorption process were not only affected by the variation in experimental conditions but also by the chemical structure of the adsorbate molecules for the same adsorbent.

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Adsorption Thermodynamics of Cr(VI) Removal by using Agro-Industrial Waste of Oil Palm Bagasse and Plantain Peels

Ingeniería e Investigación ◽

10.15446/ing.investig.v40n3.83709 ◽

2020 ◽

Vol 40 (3) ◽

pp. 22-28

Author(s):

Angel Villabona Ortíz ◽

Candelaria Nahir Tejada-Tovar ◽

Rodrigo Ortega Toro

Keyword(s):

Industrial Waste ◽

Adsorption Mechanism ◽

Adsorption Process ◽

Physical Adsorption ◽

Colorimetric Method ◽

Waste Materials ◽

Effect Of Temperature ◽

Adsorption Thermodynamics ◽

Diphenyl Carbazide ◽

Initial Preparation

The effect of temperature on the adsorption of Cr (VI) was determined with waste materials from the agroindustry, such as palm bagasse and plantain peels, by determining the thermodynamic parameters which allow to establish the mechanisms that control the process. The methodology included an initial preparation of the biomass, its characterization, and subsequent adsorption tests by setting the initial concentration of the metal to 100 ppm, a particle size of 0,5 mm, a biomass amount of 0,325 g, pH 2, and a volume of 100 mL. The process temperature varied between 303,15, and 352,15 K. The concentration of the remaining metal in the solution was performed using the diphenyl carbazide colorimetric method through a UVVis spectroscopy at a wavelength of 540 nm. The results show that the effect of temperature does not present a defined trend for palm bagasse, whereas it is linear for adsorption using plantain peels. Furthermore, the process of adsorption of Cr (VI) with palm bagasse is more favorable at higher temperatures, since it is a spontaneous process with a physical adsorption mechanism. On the other hand, the adsorption process with plantain peels is thermodynamically feasible at temperatures from 40 to 55 °C and not spontaneous at higher temperatures. Also, a physicochemical adsorption mechanism was evinced. It is concluded that the use of the studied materials is possible in the removal of the Cr (VI) ion in aqueous solutions.

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Removal of Nickel from Aqueous Solutions by Natural Bentonites from Slovakia

Materials ◽

10.3390/ma14020282 ◽

2021 ◽

Vol 14 (2) ◽

pp. 282

Author(s):

Matej Šuránek ◽

Zuzana Melichová ◽

Valéria Kureková ◽

Ljiljana Kljajević ◽

Snežana Nenadović

Keyword(s):

Kinetic Model ◽

Gibbs Energy ◽

Adsorption Process ◽

Effect Of Temperature ◽

Standard Entropy ◽

Order Kinetic ◽

Processing Conditions ◽

Adsorption Capacities ◽

Order Kinetic Model ◽

Pseudo Second Order

In this study, the removal of nickel (Ni(II)) by adsorption from synthetically prepared solutions using natural bentonites (Lieskovec (L), Hliník nad Hronom (S), Jelšový Potok (JP), and Stará Kremnička (SK)) was investigated. All experiments were carried out under batch processing conditions, with the concentration of Ni(II), temperature, and time as the variables. The adsorption process was fast, approaching equilibrium within 30 min. The Langmuir maximum adsorption capacities of the four bentonite samples used were found to be 8.41, 12.24, 21.79, and 21.93 mg g–1, respectively. The results best fitted the pseudo-second-order kinetic model, with constant rates in a range of 0.0948–0.3153 g mg–1 min. The effect of temperature was investigated at temperatures of 20, 30, and 40 °C. Thermodynamic parameters, including standard enthalpy (ΔH0), Gibbs energy (ΔG0), and standard entropy (ΔS0), were calculated. The adsorption of Ni(II) by bentonite samples was an endothermic and spontaneous process. These results indicated that, of the bentonite samples used, the natural bentonites from JP and SK were most suitable for the removal of nickel from synthetically prepared solutions.

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Easy Preparation of Liposome@PDA Microspheres for Fast and Highly Efficient Removal of Methylene Blue from Water

International Journal of Molecular Sciences ◽

10.3390/ijms222111916 ◽

2021 ◽

Vol 22 (21) ◽

pp. 11916

Author(s):

Vincenzo De Leo ◽

Anna Maria Maurelli ◽

Chiara Ingrosso ◽

Fabio Lupone ◽

Lucia Catucci

Keyword(s):

Methylene Blue ◽

High Efficiency ◽

Adsorption Process ◽

Water Remediation ◽

Order Kinetic ◽

Experimental Conditions ◽

Weakly Alkaline ◽

Effects Of Ph ◽

Order Kinetic Model ◽

Alkaline Conditions

Mussel-inspired chemistry was usefully exploited here with the aim of developing a high-efficiency, environmentally friendly material for water remediation. A micro-structured material based on polydopamine (PDA) was obtained by using liposomes as templating agents and was used for the first time as an adsorbent material for the removal of methylene blue (MB) dye from aqueous solutions. Phospholipid liposomes were made by extrusion and coated with PDA by self-polymerization of dopamine under simple and mild conditions. The obtained Liposome@PDA microspheres were characterized by DLS and Zeta potential analysis, TEM microscopy, and FTIR spectroscopy. The effects of pH, temperature, MB concentration, amount of Liposome@PDA, and contact time on the adsorption process were investigated. Results showed that the highest adsorption capacity was obtained in weakly alkaline conditions (pH = 8.0) and that it could reach up to 395.4 mg g−1 at 298 K. In addition, adsorption kinetics showed that the adsorption behavior fits a pseudo-second-order kinetic model well. The equilibrium adsorption data, instead, were well described by Langmuir isotherm. Thermodynamic analysis demonstrated that the adsorption process was endothermic and spontaneous (ΔG0 = −12.55 kJ mol−1, ΔH0 = 13.37 kJ mol−1) in the investigated experimental conditions. Finally, the applicability of Liposome@PDA microspheres to model wastewater and the excellent reusability after regeneration by removing MB were demonstrated.

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A chitosan fiber as green material for removing Cr(VI) ions and Cu(II) ions pollutants

Scientific Reports ◽

10.1038/s41598-021-02399-5 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Shujie Zhang ◽

Yating Zhang ◽

Lisong Fu ◽

Mengke Jing

Keyword(s):

Metal Ions ◽

Adsorption Process ◽

Ph Value ◽

Copper Ions ◽

Physical Adsorption ◽

Thermodynamic Characteristics ◽

Fiber Material ◽

Thermal Reaction ◽

Order Kinetic ◽

Chromium Ions

AbstractThe application shell uses cellulose as a green and recyclable fiber material, which has great value in the field of water treatment environment. Varying factors, including pH value, dosage of CS, reaction time and original Cr(VI) ions and Cu(II) ions were studied to investigate the Cr(VI) and Cu(II) ions removal efficiency. The obtained shell trichlorocellulose has better permeability to copper ions, which is mainly due to the different oxide states of copper ions and chromium ions in a pH environment, which lead to different combinations. The price of shell cellulose neutralization is relatively low. Metal ions have better absorption properties. The kinetic and thermodynamic characteristics of the adsorption process of copper ions by chitosan yarns were discussed. The adsorption process of copper ions conformed to the quasi-second-order kinetic equation. It can be fitted by Langmuir isotherm. The adsorption of copper ions by the yarn is a spontaneous thermal reaction with both physical adsorption and chemical adsorption. Compared with chromium ions, chitosan fibers have better adsorption of copper ions, which is mainly because the amino groups in chitosan fibers can have good chelation with copper ions. SEM, FTIR, XRD were used to characterize the adsorption of copper ions by chitosan fibers, and the mechanism of the adsorption of metal ions by chitosan fibers was explored.

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