scholarly journals Kinetic and thermodynamic studies on the adsorption of Cu2+ ions from aqueous solution by using agricultural waste-derived biochars

2020 ◽  
Vol 20 (8) ◽  
pp. 3120-3140
Author(s):  
Nihan Kaya ◽  
Ferhat Arslan ◽  
Zeynep Yıldız Uzun ◽  
Selim Ceylan

Abstract In this study, it was aimed to investigate the adsorption properties of the biochars obtained by pyrolysis of hazelnut and walnut shells for removal of copper ions from aqueous solutions. The characterization of raw biomasses and also biochars were performed using TGA-DTG, FT-IR, BET, SEM, partial and elemental analysis techniques. The optimum conditions were determined by investigating the effect of adsorption parameters (initial concentration, temperature, adsorbent amount, pH, contact time and mixing speed) for efficient removal of copper ions from aqueous solution by batch adsorption experiments carried out under different conditions. The highest adsorption efficiencies were recorded as 82 and 86% respectively for hazelnut and walnut shell biochars at pH 4, Co = 15 ppm, adsorbent dosage = 3 g/L and mixing speed = 600 rpm. Experimental results showed that the adsorption efficiency for copper ions increased with the increase of temperature (T = 45 °C) in studies only using biochar obtained from hazelnut shell. While the time of equilibrium in the aqueous solution containing copper ions was determined to be 75 min for walnut shell char, this duration was 30 min for hazelnut shell char. The experimental results were investigated in terms of Langmuir, Freundlich and Temkin isotherm models. Together with the calculated thermodynamic parameters, the adsorption mechanism was explained. In order to determine the kinetic model of the adsorption process, the experimental data were applied to pseudo first-order, pseudo second-order and intra-particle diffusion models, and the model constants were investigated.

2017 ◽  
Vol 76 (2) ◽  
pp. 478-489 ◽  
Author(s):  
Nihan Kaya

One of the major environmental problems is the existence of dye materials in water sources. This pollutant must be removed from water by appropriate methods. Although most of these methods are efficient for the treatment of waters contaminated with dye pollutants, they are very costly and commercially unattractive. Adsorption is one of the most popular methods for the removal of dye pollutants from water especially if the sorbent is inexpensive. Sorbents are classified as natural sorbents, commercial sorbents, and the sorbents obtained from industrial and agricultural wastes. Although commercial activated carbon is widely used in wastewater treatment applications, it is very expensive. In this study, usability of inexpensive materials – sepiolite as a natural adsorbent, and walnut shell and hazelnut shell as agricultural wastes – was investigated instead of commercial activated carbon to remove some azo dyes (methyl red, methyl orange and methyl yellow) from aqueous solution. Batch experiments were carried out to determine the effect of different adsorption parameters such as pH, initial dye concentration, contact time, adsorbent dose and temperature. The equilibrium of adsorptions was modeled using Langmuir and Freundlich isotherm models. This comprehensive study showed that these alternative adsorbents had sufficient binding capacity to remove these azo dyes from water.


2018 ◽  
Vol 3 (1) ◽  
pp. 13
Author(s):  
Muhammad Ali Zulfikar ◽  
Afdal Bahri ◽  
Muhamad Nasir

<p>The main objective of this study is to investigate the isotherm sorption of humic acid (HA) from aqueous solution onto dual nanofiber PMMA/PVDF. Batch adsorption experiments were carried out using HA solution as an adsorbate under variety of concentration in the range of 50-200 mg/L. The experimental data were analyzed by the Langmuir, Freundlich and Sips models of adsorption. The experimental results indicate that, the adsorption capacity of HA adsorption increases with an increase in the HA concentrations. The adsorption of HA onto dual nanofiber PMMA/PVDF agrees well with the Langmuir isotherm models with the maximum adsorption capacity was found to be 137.40 mg g<sup>-1</sup> at concentration of 100 mg L<sup>-1</sup>.</p>


2017 ◽  
Vol 889 ◽  
pp. 221-225
Author(s):  
Nur Aqilah Zainal ◽  
Shariff Ibrahim ◽  
Borhannuddin Arifin

Cocoa pod husk, an agricultural waste was chemically modified using Zinc Chloride (ZnCl2) and used as an adsorbent for removal of acid dyes; (i) Acid Violet 17 (AV17) and (ii) Acid Yellow 36 (AY36) from aqueous solution. The raw (CPHC) and chemically modified cocoa pod husk carbon (ZCPHC) were characterized by Field Emission Scanning Electron Microscopy (FESEM) and Energy Dispersive X-ray (EDX). The adsorption was performed on removing AV17 and AY36 from aqueous solution in batch adsorption system. The experimental data was simulated using Langmuir and Freundlich isotherm models. The isotherm study revealed that the AV17 adsorption on ZCPHC matched well with the Langmuir model, whereas AY36 adsorption on ZCPHC fitted well with Freundlich model. The maximum adsorption capacity determined from the Langmuir isotherm was 11.02 mg/g and 11.37 mg/g for AV17 and AY36 respectively at room temperature.


2006 ◽  
Vol 3 (4) ◽  
pp. 218-229 ◽  
Author(s):  
R. Shanmugavalli ◽  
P. S. Syed Shabudeen ◽  
R. Venckatesh ◽  
K. Kadirvelu ◽  
S. Madhavakrishnan ◽  
...  

Activated carbon prepared from silk cotton hull (SCH) was used for the adsorptive removal of Pb(II) ion from aqueous solution. The raw material used for the preparation of activated carbon is the waste of agricultural product; the production of this carbon is expected to be economically feasible. Parameters such as agitation time, metal ion concentration, adsorbent dose,pH and Particle size were studied. Adsorption equilibrium was reached within 80 min for 10, 20, 30 and 40mg/l of Pb(II) ion with 50mg of carbon per mL of solution. Adsorption parameters were determined using both Langmuir and Freundlich isotherm models. The adsorption efficiency reached 100% for 20, 30 and 40mg/l of Pb(II) ion with 120, 140 and 150mg of carbon. Pb(II) ion removal increased as thepH increased from 2 to 5 and remains constant up topH 10. Desorption studies were also carried out with dilute hydrochloric acid to know the mechanism of adsorption. Quantitative desorption of Pb(II) ion from carbon indicates that adsorption of metal ion is by ion-exchange. Efficiency of the adsorption of SCH was also studied with Pb containing industrial wastewater by varyingpH and carbon concentration.


Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 63
Author(s):  
Maria Harja ◽  
Gabriela Buema ◽  
Nicoleta Lupu ◽  
Horia Chiriac ◽  
Dumitru Daniel Herea ◽  
...  

Fly ash/magnetite material was used for the adsorption of copper ions from synthetic wastewater. The obtained material was characterized by scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDAX), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FTIR), Brunauer–Emmett–Teller (BET) surface area, and vibrating sample magnetometer (VSM). Batch adsorption experiments were employed in order to investigate the effects of adsorbent dose, initial Cu (II) concentration and contact time over adsorption efficiency. The experimental isotherms were modeled using Langmuir (four types of its linearization), Freundlich, Temkin, and Harkins–Jura isotherm models. The fits of the results are estimated according to the Langmuir isotherm, with a maximum adsorption capacity of 17.39 mg/g. The pseudo-second-order model was able to describe kinetic results. The data obtained throughout the study prove that this novel material represents a potential low-cost adsorbent for copper adsorption with improved adsorption capacity and magnetic separation capability compared with raw fly ash.


2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Aamir Abbas ◽  
Basim Ahmed Abussaud ◽  
Ihsanullah ◽  
Nadhir A. H. Al-Baghli ◽  
Halim Hamid Redhwi

Multiwall carbon nanotubes (CNTs) and iron oxide impregnated carbon nanotubes (CNTs-iron oxide) were investigated for the adsorption of hazardous toluene and paraxylene (p-xylene) from aqueous solution. Pure CNTs were impregnated with iron oxides nanoparticles using wet impregnation technique. Various characterization techniques including thermogravimetric analysis, scanning electron microscopy, elemental dispersion spectroscopy, X-ray diffraction, and nitrogen adsorption analysis were used to study the thermal degradation, surface morphology, purity, and surface area of the materials. Batch adsorption experiments show that iron oxide impregnated CNTs have higher degree of removal of p-xylene (i.e., 90%) compared with toluene (i.e., 70%), for soaking time 2 h, with pollutant initial concentration 100 ppm, at pH 6 and shaking speed of 200 rpm at 25°C. Pseudo-second-order model provides better fitting for the toluene and p-xylene adsorption. Langmuir and Freundlich isotherm models demonstrate good fitting for the adsorption data of toluene and p-xylene.


2019 ◽  
Vol 20 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Alyaa F. Ali ◽  
Ziad T. Abd Ali

The sorption of Cu2+ ions from synthetic wastewater using crushed concrete demolition waste (CCDW) which collected from a demolition site was investigated in a batch sorption system. Factors influencing on sorption process such as shaking time (0-300min), the initial concentration of contaminant (100-750mg/L), shaking speed (0-250 rpm), and adsorbent dosage (0.05-3 g/ml) have been studied. Batch experiments confirmed that the best values of these parameters were (180 min, 100 mg/l, 250 rpm, 0.7 g CCDW/100 ml) respectively where the achieved removal efficiency is equal to 100%. Sorption data were described using four isotherm models (Langmuir, Freundlich, Redlich-Peterson, and Radke-Prausnitz). Results proved that the pure adsorption and precipitation are the main mechanisms for removal of copper ions from aqueous solution onto CCDW and sorption data can be represented by Langmuir and Radke-Prausnitz model. The copper ion was successfully removed from aqueous solution during batch experiments using CCDW in the particle size range 2–1 mm. Scanning electron microscopy detected that the removal of Cu2+ was found to arise from surface precipitation.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Fatemeh Ezati ◽  
Ebrahim Sepehr ◽  
Fatemeh Ahmadi

AbstractWater pollution is a major global challenge given the increasing growth in the industry and the human population. The present study aims to investigate the efficiency of TiO2 and γ-Al2O3 nanoadsorbents for removal of copper (Cu(II)) from aqueous solution as influenced by different chemical factors including pH, initial concentration, background electrolyte and, ionic strength. The batch adsorption experiment was performed according to standard experimental methods. Various isotherm models (Freundlich, Langmuir, Temkin, and Dubinin–Radushkevich) were fitted to the equilibrium data. According to geochemical modeling data, adsorption was a predominant mechanism for Cu(II) removal from aqueous solution. Calculated isotherm equations parameters were evidence of the physical adsorption mechanism of Cu(II) onto the surface of the nanoparticles. The Freundlich adsorption isotherm model could well fit the experimental equilibrium data at different pH values. The maximum monolayer adsorption capacity of TiO2 and γ-Al2O3 nanosorbents were found to 9288 and 3607 mg kg−1 at the highest pH value (pH 8) and the highest initial Cu(II) concentration (80 mg L−1) respectively. Copper )Cu(II) (removal efficiency with TiO2 and γ-Al2O3 nanoparticles increased by increasing pH. Copper )Cu(II) (adsorption deceased by increasing ionic strength. The maximum Cu(II) adsorption (4510 mg kg−1) with TiO2 nanoparticles was found at 0.01 M ionic strength in the presence of NaCl. Thermodynamic calculations show the adsorption of Cu(II) ions onto the nanoparticles was spontaneous in nature. Titanium oxide (TiO2) nanosorbents could, therefore, serve as an efficient and low-cost nanomaterial for the remediation of Cu(II) ions polluted aqueous solutions.


2020 ◽  
Vol 13 (2) ◽  
pp. 15-27 ◽  
Author(s):  
Bolanle M. Babalola ◽  
Adegoke O. Babalola ◽  
Cecilia O. Akintayo ◽  
Olayide S. Lawal ◽  
Sunday F. Abimbade ◽  
...  

Abstract. In this study, the adsorption of Ni(II) and Cu(II) ions from aqueous solutions by powdered Delonix regia pods and leaves was investigated using batch adsorption techniques. The effects of operating conditions such as pH, contact time, adsorbent dosage, metal ion concentration and the presence of sodium ions interfering with the sorption process were investigated. The results obtained showed that equilibrium sorption was attained within 30 min of interaction, and an increase in the initial concentration of the adsorbate, pH and adsorbent dosage led to an increase in the amount of Ni(II) and Cu(II) ions adsorbed. The adsorption process followed the pseudo-second-order kinetic model for all metal ions' sorption. The equilibrium data fitted well with both the Langmuir and Freundlich isotherms; the monolayer adsorption capacity (Q0 mg g−1) of the Delonix regia pods and leaves was 5.88 and 5.77 mg g−1 for Ni(II) ions respectively and 9.12 and 9.01 mg g−1 for Cu(II) ions respectively. The efficiency of the powdered pods and leaves of Delonix regia with respect to the removal of Ni(II) and Cu(II) ions was greater than 80 %, except for the sorption of Ni(II) ions onto the leaves. The desorption study revealed that the percentage of metal ions recovered from the pods was higher than that recovered from the leaves at various nitric acid concentrations. This study proves that Delonix regia biomass, an agricultural waste product (“agro-waste”), could be used to remove Ni(II) and Cu(II) ions from aqueous solution.


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