Removal of caffeine by oxidized biochar

2020 ◽  
Author(s):  
Ioannis Anastopoulos ◽  
Ioannis Pashalidis ◽  
Artis Robalds
Keyword(s):  
Contact Time ◽  
Electrostatic Interactions ◽  
Plant Biomass ◽  
Freundlich Isotherm ◽  
Outer Sphere ◽  
Initial Step ◽  
Order Kinetic ◽  
Surface Complexes ◽  
Order Kinetic Model ◽  
Repulsive Forces

<p>Oxidized biochar from plant biomass (OBPM) was used to remove caffeine (CF) from aqueous solutions. Among examined parameters that affect adsorption, pH was found to play the most important role. By increasing the initial pH from 2 to 4, the adsorption capacity of CF was increased, whereas for pH above 4, a decline of the adsorption efficiency was noticed. The effect of contact time was also investigated in the range of 1 – 150 minutes and results indicated that the adsorption process consists of two steps. The initial step was relatively fast most probably, because a large number of adsorption surface sites was available, and with proceeding contact time the adsorption rate declined. The latter could be attributed to the decreasing number of vacant sites and to the development of repulsive forces between the free CF molecules and the occupied OBPM surface. The experimental data were best fitted by the pseudo-second order kinetic, compared to pseudo-first order kinetic model and the Freundlich isotherm model better fitted the data. The raise of temperature from 25 to 50 °C affected negatively the CF removal, indicating the exothermicity of the adsorption. Finally, FTIR spectroscopic data and investigations on the effect of ionic strength indicated that the adsorption mechanism is mainly based on electrostatic interactions and the formation of outer sphere surface complexes.</p><p><strong> </strong></p>

Preparation of titanate nanoflower for sorption of 75Se(IV) radioisotope from aqueous solution: Equilibrium, kinetic and thermodynamic studies

2015 ◽  
Vol 103 (12) ◽  
Author(s):  
Sahar El-Sayed Abd El-Kader Sharaf El-Deen ◽  
Karam Fatwhi Allan ◽  
Mohamed Holeil ◽  
Gehan El-Sayed Abd El-Kader Sharaf El-Deen
Keyword(s):  
Aqueous Solution ◽  
Electrostatic Interactions ◽  
Outer Sphere ◽  
Solution Temperature ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
X Ray ◽  
Adsorptive Removal ◽  
Order Kinetic Model

AbstractIn this study, the adsorptive removal of selenium (IV) from aqueous solution by titanate nanoflower (TNF) was prepared via alkaline hydrothermal method. The morphology and crystal phase of the TNF were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscope (EDX), selected area electron diffraction (SAED), thermogravimetric analysis (TGA), fourier transform infrared spectroscopy (FTIR) and specific surface area. This study was conducted to determine the influence of various operating parameters such as pH, adsorbate weight, initial anion concentration, contact time and solution temperature on the adsorptive removal of selenium (IV). Equilibrium adsorption data were analyzed using Freundlich, Langmuir and Dubinin–Radushkevich (D–R) isotherm models. The results demonstrated that the adsorption was well described by the Langmuir adsorption isotherm with the maximum adsorption capacity up to 46.52 mg/g at pH 3.5. The adsorption of Se(IV) anions onto the surface of TNF may proceed through outer sphere electrostatic interactions and/or inner-sphere complexation interaction. The kinetic data indicated that the adsorption fit well with the pseudo-second-order kinetic model. The thermodynamic parameters implied that the adsorption process was spontaneous and endothermic in nature.

scholarly journals Aqueous Phase Adsorption of Pb (II) Ions onto Hymenoptera sphecidae (Mud-wasp) Nest

2020 ◽  
pp. 21-31
Author(s):  
Donald T. Kukwa ◽  
Peter A. Adie ◽  
Rose E. Kukwa ◽  
Paula D. Kungur
Keyword(s):  
Contact Time ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Batch Process ◽  
Second Order ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Best Fit ◽  
Adsorbent Dose

Removal of Pb (II) ion from aqueous solution using Hymenoptera sphecidae (mud-wasp) nest was investigated using a batch process. The effect of pH, contact time and adsorbent dose were also investigated. The result showed that the adsorption of Pb (II) ion onto mud-wasp nest was dependent on pH, contact time and adsorbent dose. Adsorption patterns were analysed in terms of three bi-parameter isotherms of Langmuir, Freundlich and Temkin. Freundlich isotherm gave the best fit to the adsorption data with a correlation coefficient of 0.992, while monolayer sorption capacity yielded 41.667 mg/g. Lagergren’s pseudo first-order and pseudo second-order kinetic models were used to test the adsorption kinetics. The kinetic data were well described by the pseudo second-order kinetic model, suggesting that the process was chemisorption type.  The results showed that mud-wasp nest can be used as a low-cost adsorbent for the removal of Pb (II) ion from aqueous solutions.

scholarly journals Barium/Cobalt@Polyethylene Glycol Nanocomposites for Dye Removal from Aqueous Solutions

Polymers ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1161
Author(s):  
Somayeh Rahdar ◽  
Abbas Rahdar ◽  
Mostafa Sattari ◽  
Laleh Divband Hafshejani ◽  
Athanasia K. Tolkou ◽  
...  
Keyword(s):  
Polyethylene Glycol ◽  
Aqueous Solutions ◽  
Removal Efficiency ◽  
Contact Time ◽  
Skin Diseases ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Initial Concentration ◽  
Adsorbent Dosage ◽  
Order Kinetic Model

Dyes are known as one of the most dangerous industrial pollutants which can cause skin diseases, allergy, and provoke cancer and mutation in humans. Therefore, one of the important environmental issues is the effective removal of dyes from industrial wastewater. In the current work, BaFe12O19/CoFe2O4@polyethylene glycol (abbreviated as BFO/CFO@PEG) nanocomposite was synthesized and evaluated regarding its capacity for adsorptive removal of a model dye Acid Blue 92 (denoted as AB92) from aqueous solutions. The characteristics of the prepared nanocomposite was determined by tests such as X-ray diffraction (XRD), scanning electron microscope (SEM), vibration sample magnetization (VSM), and Fourier transform infrared spectroscopy (FTIR). The effects of conditional parameters including pH (2–12), initial concentration of dye (20–100 mg/L), adsorbent dosage (0.02–0.1 g/L) and contact time (0-180 min) on the adsorption of dye were investigated and then optimized. The results indicated that with the increase of the adsorbent dosage from 0.02 to 0.1 g/L, the removal efficiency increased from 74.1% to 78.6%, and the adsorbed amount decreased from 148.25 to 31.44 mg/g. The maximum removal efficiency (77.54%) and adsorption capacity (31.02 mg/g) were observed at pH 2. Therefore, the general optimization conditions revealed that the maximum adsorption efficiency of dye was obtained in condition of initial concentration of 20 mg/L, contact time of 1 h and pH of solution equal 2. The adsorption isotherm and kinetic data were evaluated using a series of models. The pseudo-second order kinetic model and Freundlich isotherm model show the best fitting with experimental data with R2∼0.999.

scholarly journals Adsorption of Phosphate from Aqueous Solution onto Iron-coated Waste Mussel Shell: Physicochemical Characteristics, Kinetic, and Isotherm Studies

2021 ◽  
Vol 11 (5) ◽  
pp. 12831-12842
Keyword(s):  
Aqueous Solution ◽  
Contact Time ◽  
Low Cost ◽  
Freundlich Isotherm ◽  
Physicochemical Characteristics ◽  
Order Kinetic ◽  
Mussel Shell ◽  
Order Kinetic Model ◽  
Synthetic Solution ◽  
Pseudo Second Order

High amounts of phosphate (PO43–) discharged in receiving water can lead to eutrophication, which endangers life below water and human health. This study elucidates the removal of PO43– from synthetic solution by iron-coated waste mussel shell (ICWMS). The PO43– adsorption by ICWMS was determined at different process parameters, such as initial PO43– concentration (7 mg L−1), solution volume (0.2 L), adsorbent dosage (4, 8, 12, 16, and 20 g), and contact time. The highest efficiency of PO43− removal can reach 96.9% with an adsorption capacity of 0.30 mg g−1 could be obtained after a contact time of 48 h for the use of 20 g of ICWMS. Batch experimental data can be well described by the pseudo-second-order kinetic model (R2 = 0.999) and Freundlich isotherm model (R2 = 0.996), suggesting that chemisorption and multilayer adsorption occurred. The efficiency of PO43– removal from aqueous solution by ICWMS was verified to contribute to applying a new low-cost adsorbent obtained from waste mussel shell in the field of wastewater treatment.

scholarly journals Synthesis Of Paramagnetic Merkapto Silica Hybrid From Rice Husk Ash For Ag(I) Adsorben

2018 ◽  
Vol 1 (2) ◽  
pp. 30
Author(s):  
Saral Dwi Miftiyati ◽  
Saprini Hamdiani ◽  
Made Ganesh Darmayanti
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Contact Time ◽  
Rice Husk Ash ◽  
Freundlich Isotherm ◽  
Isotherm Model ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Silica Hybrids ◽  
Silica Hybrid

A study has been conducted on the synthesis of paramagnetic mercapto silica hybrids as metal adsorbent of Ag(I). The aim of this study was to synthesis paramagnetic mercapto silica hybrid from rice husk ash waste, knowing the characteristics of paramagnetic mercapto silica hybrid from rice husk ash waste, and to determine the effect of pH, metal ions concentration, and the contact time on the value of adsorption capacity (Q). Based on the results of the study, it was found that paramagnetic mercapto silica hybrids can be synthesized from the rice husk ash waste. Characterization using FTIR spectroscopy showed that silanol (Si-OH), siloxan (Si-O-Si), -SH, and Fe-OH functional groups, and characterization of paramagnetic mercapto silica hybrid structures using XRD to show crystalline compounds with a position value of 2θ = 35.4 which showed that the magnetite material of Fe3O4 was coated by silica. Paramagnetic mercapto silica hybrids from rice husk waste can be used as adsorbent of Ag (I) metal at optimum conditions of pH 3, contact time of 120 minutes, and adsorption capacity of 392.01 mg/g. The suitable isotherm model is the Freundlich isotherm model which means the absorption of metal Ag (I) occurs physically, while adsorption of kinetics followed the pseudo II order kinetic model with a value of k  = 3.01 g.mg-1 minute-1.

scholarly journals Removal of Methyl Orange from Aqueous Solutions by Adsorption Using Corn Leaves as Adsorbent Material

2019 ◽  
Vol 25 (4) ◽  
pp. 55-69
Author(s):  
Omar Hisham Fadhil ◽  
Mohammed Y. Eisa
Keyword(s):  
Methyl Orange ◽  
Contact Time ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Order Model ◽  
Several Variables ◽  
Adsorption Data ◽  
Equilibrium Data ◽  
Order Kinetic Model ◽  
Pseudo Second Order

A comparative study was done on the adsorption of methyl orange dye (MO) using non-activated and activated corn leaves with hydrochloric acid as an adsorbent material. Scanning electron microscopy (SEM) and Fourier Transform Infrared spectroscopy (FTIR) were utilized to specify the properties of adsorbent material. The effect of several variables (pH, initial dye concentration, temperature, amount of adsorbent and contact time) on the removal efficiency was studied and the results indicated that the adsorption efficiency increases with the increase in the concentration of dye, adsorbent dosage and contact time, while inversely proportional to the increase in pH and temperature for both the treated and untreated corn leaves. The equilibrium data is best fitted to Freundlich isotherm for untreated adsorbent, while Langmuir isotherm show best agreement with the data when the treated adsorbent is used. The rate of adsorption was found to follow the pseudo first order kinetic model (PFO) when non-activated adsorbent is used, while the pseudo second order model (PSO) is fitted to the adsorption data using activated adsorbent.  

scholarly journals Sawdust for the Removal of Heavy Metals from Water: A Review

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4318
Author(s):  
Elie Meez ◽  
Abbas Rahdar ◽  
George Z. Kyzas
Keyword(s):  
Heavy Metals ◽  
Adsorption Mechanism ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Suitable Material ◽  
Removal Of Heavy Metals ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
And Control ◽  
Environmental Agencies

The threat of the accumulation of heavy metals in wastewater is increasing, due to their abilities to inflict damage to human health, especially in the past decade. The world’s environmental agencies are trying to issue several regulations that allow the management and control of random disposals of heavy metals. Scientific studies have heavily focused on finding suitable materials and techniques for the purification of wastewaters, but most solutions have been rejected due to cost-related issues. Several potential materials for this objective have been found and have been compared to determine the most suitable material for the purification process. Sawdust, among all the materials investigated, shows high potential and very promising results. Sawdust has been shown to have a good structure suitable for water purification processes. Parameters affecting the adsorption mechanism of heavy metals into sawdust have been studied and it has been shown that pH, contact time and several other parameters could play a major role in improving the adsorption process. The adsorption was found to follow the Langmuir or Freundlich isotherm and a pseudo second-order kinetic model, meaning that the type of adsorption was a chemisorption. Sawdust has major advantages to be considered and is one of the most promising materials to solve the wastewater problem.

scholarly journals Phenol adsorption from wastewater using cashew nut shells as adsorbent

2018 ◽  
Vol 7 (3) ◽  
pp. 966
Author(s):  
Kartik Kulkarni ◽  
Varsha Sudheer ◽  
C R Girish
Keyword(s):  
Agricultural Waste ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Multilayer Adsorption ◽  
Phenol Adsorption ◽  
Cashew Nut ◽  
Experimental Parameters ◽  
Order Kinetic Model

The potential of agricultural waste cashew nut shells as an adsorbent for removing phenol from wastewater is presented in this paper. The adsorbent was treated with 3M sulphuric acid in order to improve the properties. The experimental parameters such as adsorbent dosage, concentration and temperature were optimized with response surface methodology (RSM). The isotherm data were tested with different isotherm models and it obeyed Freundlich Isotherm showing the multilayer adsorption. The kinetic data satisfied pseudo-first order kinetic model. The maximum adsorption capacity was calculated to be 35.08 mg/g proving the capability of cashew nut shells for removing phenol from wastewater.  

scholarly journals Biosorption of Congo Red and Methylene Blue by pretreated waste Streptomyces fradiae biomass - Equilibrium, kinetic and thermodynamic studies

2018 ◽  
Vol 83 (1) ◽  
pp. 107-120 ◽  
Author(s):  
Zdravka Velkova ◽  
Gergana Kirova ◽  
Margarita Stoytcheva ◽  
Velizar Gochev
Keyword(s):  
Methylene Blue ◽  
Congo Red ◽  
Contact Time ◽  
Order Kinetic ◽  
Batch Experiments ◽  
Streptomyces Fradiae ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Kinetic And Thermodynamic Studies ◽  
Pretreated Biomass

Pretreated waste Streptomyces fradiae biomass was utilized as an eco-friendly sorbent for Congo Red (CR) and Methylene Blue (MB) removal from aqueous solutions. The biosorbent was characterized by Fourier transform infrared spectroscopy. Batch experiments were conducted to study the effect of pH, biosorbent dosage, initial concentration of adsorbates, contact time and temperature on the biosorption of the two dyes. The equilibrium adsorption data were analysed using Freundlich and Langmuir models. Both models fitted well the experimental data. The maximum biosorption capacity of the pretreated Streptomyces fradiae biomass was 46.64 mg g-1 for CR and 59.63 mg g-1 for MB, at a pH 6.0, with the contact time of 120 min, the biosorbent dosage of 2 g dm-3 and the temperature of 298 K. Lagergren and Ho kinetic models were used to analyse the kinetic data obtained from different batch experiments. The biosorption of both dyes followed better the pseudo-second order kinetic model. The calculated values for ?G, ?S, and ?H indicated that the biosorption of CR and MB onto the waste pretreated biomass was feasible, spontaneous, and exothermic in the selected temperature range and conditions.

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.

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