scholarly journals Equilibrium Study, Modeling and Optimization of Model Drug Adsorption Process by Sunflower Seed Shells

2020 ◽  
Vol 10 (9) ◽  
pp. 3271 ◽  
Author(s):  
Bahdja Hayoun ◽  
Mustapha Bourouina ◽  
Marta Pazos ◽  
Mª Angeles Sanromán ◽  
Saliha Bourouina-Bacha

The adsorption capacity of the medication methylthioninium chloride (MC) from aqueous solution onto sunflower seed shells (SSS), a low cost and abundant alternative adsorbent, was investigated in a batch system. The surface properties of the adsorbent were characterized by Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), specific surface area (by using the Brunauer–Emmett–Teller equation), the liquid displacement method and pHPZC. The ability of SSS to remove the medication was assessed through kinetic, thermodynamic and equilibrium investigations. The adsorption efficiency of the SSS adsorbent for the removal of MC was evaluated considering the effects of its concentration, temperature, adsorption contact time, and the pH of the medium. The results obtained from the kinetic and isotherm studies show that the adsorption of the MC on SSS follows pseudo-second-order kinetics (R² > 0.99) and the Temkin isotherm model (R² = 0.97), respectively. The thermodynamic study showed that the adsorption was endothermic and spontaneous, according to its physisorption mechanism. The mathematical modeling of this process was carried out by using the surface response methodology of Box–Behenken. It was possible to deduce a statistically reliable regression equation that related the adsorption yield to the chosen operating parameters, that is, the initial MC concentration, the adsorbent dosage and the pH. Analysis of the variance indicated that the most influential parameters were the SSS dosage, the pH and their interaction and showed the optimal values for ensuring the best adsorption capacity of 95.58%.

Author(s):  
Joshua O. Ighalo ◽  
Ibrahim O. Tijani ◽  
Oluwaseun J. Ajala ◽  
Fisayo O. Ayandele ◽  
Omodele A. Eletta ◽  
...  

Background: Modified bio-based adsorbents from plant sources can be used for pollution remediation by adsorption due to their low cost and availability in large quantities. Objective: In this study, the competitive biosorption of Pb(II) and Cu(II) by Micropogonias undulates functionalised fish scales (FFS) was conducted. The functionalisation was done by wet impregnation with Fe2+. Method: The biosorbent was characterised by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS) and Branueur–Emmett–Teller (BET) analyses. Results: The major constituents in the FFS were calcium and phosphorus from the collagen and apatite on the scales. Optimum removal efficiency for both metals was >99% at 10 g/l dosage. It was observed that the Langmuir isotherm model and the pseudo second order kinetics model were the best fit for the experimental data. The monolayer adsorption capacity of FFS for Pb(II) and Cu(II) was observed to be 96.15 mg/g and 100 mg/g respectively. Conclusion: The study revealed that the competitive biosorption of heavy metals can be achieved (at a good adsorption capacity) using functionalised Micropogonias undulates fish scales.


2012 ◽  
Vol 65 (8) ◽  
pp. 1341-1349 ◽  
Author(s):  
Shokooh Sadat Khaloo ◽  
Amir Hossein Matin ◽  
Sahar Sharifi ◽  
Masoumeh Fadaeinia ◽  
Narges Kazempour ◽  
...  

The application of almond shell as a low cost natural adsorbent to remove Hg2+ from aqueous solution was investigated. Batch experiments were carried out to evaluate the adsorption capacity of the material. The chemical and physical parameters such as pH, sorbent amount, initial ion concentration, and contact time were optimized for the maximum uptake of mercury onto the solid surface. Adsorption isotherms were expressed by Langmuir and Freundlich adsorption models, and the experimental data were found to fit the Langmuir model rather than the Freundlich. The maximum adsorption capacity obtained from the Langmuir isotherm was 135.13 mg/g. A kinetic study was carried out with pseudo-first-order and pseudo-second-order reaction equations and it was found that the Hg2+ uptake process followed the pseudo-second-order rate expression. The thermodynamic values, ΔG0, ΔH0 and ΔS0, indicated that adsorption was an endothermic and spontaneous process. The potential of this material for mercury elimination was demonstrated by efficient Hg2+ removal from a synthetic effluent.


2020 ◽  
Vol 9 (3) ◽  
pp. 197-206
Author(s):  
Thaharah Ramadhani ◽  
Faisal Abdullah ◽  
Indra Indra ◽  
Abrar Muslim ◽  
Suhendrayatna Suhendrayatna ◽  
...  

The use of a low-cost biosorbent prepared from Ipomoea pes-caprae stem for the adsorption of Cd(II) ions from aqueous solution at different contact times, biosorbent sizes, pH values, and initial Cd(II) ions concentration solution was investigated. The biosorbent was analyzed using Fourier-transform infrared spectroscopy (FT-IR) to find important IR-active functional groups. A scanning electron microscope (SEM) was used to examine the biosorbent morphology. The experimental results showed the highest Cd(II) ions adsorption was 29.513 mg/g  under an optimal condition as initial Cd(II) ions concentration of 662.77 mg/L, 1 g dose, 80-min contact time, pH 5, 75 rpm of stirring speed, 1 atm, and 30 oC. Cd(II) ions' adsorption kinetics obeys the linearized pseudo-second-order kinetics (R2 = 0.996), and the adsorption capacity is based on the optimal condition, and the rate attained was 44.444 mg/g and 0.097 g/mg. Min, respectively. Besides, the adsorption isotherms were very well fitted by the linearized Langmuir isotherm model, and the monolayer adsorption capacity and pore volume determined was 30.121 mg/g and 0.129 L/mg, respectively. These results indicated the chemisorption nature


Gels ◽  
2021 ◽  
Vol 7 (4) ◽  
pp. 178
Author(s):  
Serap Sezen ◽  
Vijay Kumar Thakur ◽  
Mehmet Murat Ozmen

Currently, macroporous hydrogels have been receiving attention in wastewater treatment due to their unique structures. As a natural polymer, alginate is used to remove cationic dyes due to its sustainable features such as abundance, low cost, processability, and being environmentally friendly. Herein, alginate/montmorillonite composite macroporous hydrogels (cryogels) with high porosity, mechanical elasticity, and high adsorption yield for methylene blue (MB) were generated by the one-step cryogelation technique. These cryogels were synthesized by adding montmorillonite into gel precursor, followed by chemical cross-linking employing carbodiimide chemistry in a frozen state. The as-prepared adsorbents were analyzed by FT-IR, SEM, gel fraction, swelling, uniaxial compression, and MB adsorption tests. The results indicated that alginate/montmorillonite cryogels exhibited high gelation yield (up to 80%), colossal water uptake capacity, elasticity, and effective dye adsorption capacity (93.7%). Maximum adsorption capacity against MB was 559.94 mg g−1 by linear regression of Langmuir model onto experimental data. The Pseudo-Second-Order model was fitted better onto kinetic data compared to the Pseudo-First-Order model. Improved porosity and mechanical elasticity yielding enhanced dye removal capacity make them highly potential alternative adsorbents compared to available alginate/montmorillonite materials for MB removal.


2018 ◽  
Vol 9 (1) ◽  
pp. 83-93 ◽  
Author(s):  
Olushola S. Ayanda ◽  
Olusola S. Amodu ◽  
Habibat Adubiaro ◽  
Godwin O. Olutona ◽  
Oluwapese T. Ebenezer ◽  
...  

Abstract The adsorption of alizarin red (AR) dye onto termite hill sample (THs) was investigated. Prior to the adsorption studies, the elemental, morphological, surface and structural properties of THs were examined by modern analytical methods. Instrumental analysis showed that the homogenous micro-structured THs are comprised of iron oxide, silica oxide, and alumina as major components. Experiments showed that the adsorption capacity of AR decreases with increasing pH and initial AR concentrations, and increases with increasing contact time, stirring speed and temperature. The equilibrium study obeyed the Langmuir adsorption model and the kinetics followed the pseudo-second-order model. About 95.0% AR reduction (1.425 mg/g) was achieved when 0.8 g of THs was mixed with 30 mL of 40 mg/L AR solution for 120 min at 400 rpm and a pH of 2. Thermodynamic study suggested that AR adsorption onto THs is spontaneous at higher temperatures of 323 K and above (ΔGo values are negative). However, ΔGo are positive at lower temperatures of 293–313 K, which implies that the adsorption process is not spontaneous at these temperatures. This study showed that THs could be used as alternative, low-cost, natural adsorbents for the removal of dyes from wastewater.


2013 ◽  
Vol 2013 ◽  
pp. 1-15 ◽  
Author(s):  
Nady A. Fathy ◽  
Ola I. El-Shafey ◽  
Laila B. Khalil

The effectiveness of alkali-acid modification in enhancement the adsorption capacity of rice straw (RS) for removing a basic dye was studied. The obtained adsorbents were characterized by slurry pH, pHPZC, iodine number, methylene blue number, FTIR, and SEM analyses. Adsorption of methylene blue (MB) was described by the Langmuir, Freundlich, Tempkin, and Redlich-Peterson isotherm models. Effects of contact time, initial concentration of MB dye, pH of solution, adsorbent dose, salt concentration of NaCl, and desorbing agents on the removal of MB were reported. Kinetic studies were analyzed using the pseudo-first-order, pseudo-second-order, and the intraparticle diffusion models and were found to follow closely the pseudo-second-order model. Equilibrium data were best represented by the Langmuir and Redlich-Peterson isotherms. The adsorption capacities were varied between 32.6 and 131.5 mg/g for untreated and treated RS samples with NaOH-1M citric acid (ARS-1C), respectively. Adsorption behavior of the ARS-1C sample was experimented in a binary mixture containing methylene blue (basic) and reactive blue 19 (acidic) dyes which showed its ability to remove MB higher than RB19. Overall, the results indicate that the alkali-acid treatment proved to be potential modification for producing effective low-cost adsorbents for the removal of the basic dyes from wastewater.


RSC Advances ◽  
2016 ◽  
Vol 6 (82) ◽  
pp. 78936-78946 ◽  
Author(s):  
Song Cheng ◽  
Libo Zhang ◽  
Hongying Xia ◽  
Jinhui Peng ◽  
Jianhua Shu ◽  
...  

A and B are Langmuir isotherm and pseudo-second-order model. We conclude that MB adsorption capacity of Fe-activated carbon is bigger than raw activated carbon, indicating that Fe-activated carbon has better MB removal efficiency.


2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Hongxue Qi ◽  
Xianjun Niu ◽  
Haipeng Wu ◽  
Xiuping Liu ◽  
Yongqiang Chen

To investigate the adsorption behavior of Cu (I)-MOF material for chromium (VI) in water, the parameters of influencing adsorption were optimized and found as follows: the optimal pH was 6 for the adsorption of Cr (VI) by the Cu (I)-MOF, the optimal amount of adsorbent was 0.45 g·L−1, and the adsorption saturation time was within 180 min. Subsequently, the kinetics results were fitted by four models such as pseudo-first-order, pseudo-second-order, Elovich, and intraparticle diffusion models. Among them, the adsorption of chromium (VI) was more inclined to the pseudo-first-order model (Radj2 = 0.9230). Then, the isotherm data were fitted by Langmuir and Freundlich models. The results indicated that Langmuir isotherm was the excellent match model (Radj2 = 0.9827). It belongs to a monolayer adsorption, and the maximum adsorption capacity was 95.92 mg·g−1. Subsequently, the thermodynamic parameters of the adsorption were calculated as follows: enthalpy change (ΔHθ) was −8.583 kJ·mol−1, entropy change (ΔSθ) was −8.243 J·mol−1 K−1, and the Gibbs function change (ΔGθ) was less than zero in the temperature range of 288–328 K, indicating that the reaction was spontaneous. Finally, both the spectra of infrared and XPS supported the adsorption mechanism that belonged the ion exchange. The spectra of XRD and SEM images shown that the structure of Cu (I)-MOF remained stable for at least 3 cycles. In conclusion, Cu (I)-MOF material has a high adsorption capacity, good water stability, low cost, and easy to prepare in large quantities in practical application. It will be a promising adsorbent for the removal of Cr (VI) from water.


2021 ◽  
Author(s):  
Jason David

The adsorption isotherms and kinetics of two low cost adsorbents, Ladybug Sand and Greensand, were determined from multi-solute batch experiments using prepared synthetic stormwater containing arsenic, cadmium and lead. The adsorption equilibrium data were fit to the Langmuir, Freundlich and Henry isotherms using both nonlinear and linear regression techniques. Kinetic data were obtained at two different stormwater concentrations. The kinetic curves were fit to the pseudo-first-order, pseudo-second-order and homogenous surface diffusion model (HSDM). A solution to the HSDM was achieved using the user-oriented numeric solution proposed by Zhang et al. (2009). From the fitted kinetic models the reaction constants, k1 and k2, as well as the surface diffusion coefficient (Ds) were determined. The maximum service lives of adsorbent columns comprised of Ladybug Sand or Greensand were calculated using the equilibrium column model (ECM) to evaluate the feasibility of the adsorbents for use in advanced stormwater treatment.


2020 ◽  
Vol 81 (12) ◽  
pp. 2533-2544
Author(s):  
Zhanbiao Yang ◽  
Xincong Liu ◽  
Mengdi Zhang ◽  
Lixia Liu ◽  
Xiaoxun Xu ◽  
...  

Abstract We analyzed the effects of pyrolysis temperature and duration on the physiochemical properties and Cd(II) adsorption capacity of spent tea leaves (STL) biochar. The STL biochar was produced by pyrolysis at 300, 400, 500 and 600 °C for 1 and 2 h. The pyrolysis temperature was positively correlated to the ash content, pH, electrical conductivity, specific surface area (SBET), pore volume (PV) and C content, and negatively with the total yield, O, H and N content, and the O/C and H/C atomic ratios. Furthermore, the surface porosity of STL biochar increased, the density of oxygen-containing functional groups decreased, and the formation of aromatic structures was enhanced at higher pyrolysis temperatures. The adsorption of Cd(II) onto STL biochar fitted with the pseudo-second-order kinetics and Langmuir isotherms model. The STL biochar produced at 600 °C for 2 h showed the maximum Cd(II) adsorption capacity of 97.415 mg/g. In addition, Cd(II) adsorption was mainly physical and occurred in monolayers. Thus, STL biochar is a suitable low-cost adsorbent for wastewater treatment.


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