Comparative Study Of Adsorption Research Articles

Comparative adsorption study of phenol removal using Phoenix dactylifera fiber and its chemically activated carbon

Comparative adsorption study of phenol removal using Phoenix dactylifera fiber and its chemically activated carbon

Surfactant Protection Efficacy at Surfaces Varies with the Nature of Hydrophobic Materials

Monoclonal antibodies are in contact with many different materials throughout their life cycle from production to patient administration. Plastic surfaces are commonly found in single use bags, syringes, perfusion bags and tubing and their hydrophobic nature makes them particularly prone for adsorption of therapeutic proteins. The addition of surfactants in therapeutic formulations aims at minimizing surface and interface adsorption of the active molecules. However, their protection efficacy related to the nature of the plastic material is still poorly investigated. We use real-time surface-sensitive techniques and immunosorbent assays, to quantify surfactant and monoclonal antibody adsorption on hydrophobic model surfaces and different plastic polymers to analyse the effect of material surface properties on the level of surfactant protection. We show that Polysorbate 80 protects monoclonal antibodies significantly better from adsorption on a polystyrene surface than on a hexadecane self-assembled monolayer, used as a model surface with similar hydrophobicity. This enhanced protective effect on polystyrene is observed for different antibodies and also other surfactants, and its extent depends on the surfactant concentration for a given antibody concentration. A comparative adsorption study allows ranking different in-use plastics and highlights the dependence of Polysorbate 80 protection efficacy on the nature of the plastic material. This study demonstrates that, beyond hydrophobicity, the nature of plastic polymer surfaces affects surfactant adsorption and thereby impacts their protection efficacy in therapeutic antibody formulations.

Comparative Study of Adsorption of Safranin o by TiO2/Activated Carbon and Chitosan/TiO2/Activated Carbon Adsorbents

This research is a comparative study of the surface chemistry and adsorptive characteristics of titanium dioxide nanoparticles on activated carbon (Ac/TiO2) and chitosan loaded on activated carbon (Ac/TiO2/Ch). For the first time, using three-fold composite of activated carbon prepared from Persian mesquite seeds, chitosan, and nanoparticles of titanium dioxide as an effective adsorbent for removing safranin o. X-ray Diffraction (XRD), scanning electron microscope (SEM), BET analysis, and thermogravimetric analysis (TGA) have been used to determine and confirm physicochemical variation during preparing and modifying activated carbon on both adsorbents. The results of XRD, SEM, and TGA are shown essential changes happened in porosity of the surface after the modification process. The Ac/TiO2 and Ac/TiO2/Ch adsorbents have been used to /remove safranin o as a cationic azo dye from an aqueous solution. The experimental data at different conditions were correlated by some famous kinetic and isotherm models. Extrapolated data displayed dye adsorption on the Ac/TiO2, and Ac/TiO2/Ch follows the pseudo-second-order kinetic model. High efficiency and sufficient adsorption capacity in safranin o removal suggested that Ac/TiO2/Ch could be successfully used as a good candidate in water filtration.

Comparative study of Cadmium adsorption on three contrasting soils from a highly industrialized region

Evaluation of natural soils potentiality to effectively immobilize heavy metals is a fundamental tool for a sustainable management of an industrialized region. Three soil textures from Bahía Blanca Citýs industrial zone (Argentina) were analyzed to quantify Cd adsorption and assess its applicability for industrial land use. Soils textural classes corresponded to sandy loam (M1), sand (M2) and silt loam (M3). Batch adsorption kinetics and isotherms were carried out with a 1:10 soil:solution ratio. Adsorption kinetics was conducted for 240 min at constant initial Cd concentration (250 mg l−1) and varying pH (4–8 range). Adsorption isotherm was done for twenty Cd concentrations (range 0.5 mg l−1 to 460 mg l−1) and contact time of 24 h. Kinetics showed a fast instantaneous initially adsorption. Soil-water partitioning coefficient (Kd) was calculated for each concentration supplied to soils, showing a direct relationship between pH and Kd. Adsorption isotherms plots showed a nonlinear shape for M1 and M2 and a linear shape for M3. The affinity of Cd for soils is in the order: M3 > M1 > M2. Metal retention in M3 was upper than 97.8%. Langmuir, Freundlich and Dubinin-Radushkevich (DRK) adsorption models correctly reproduced experimental data. However, M1 (R2 = 0.992) and M3 (R2 = 0.985) fitted better to Freundlich model. Otherwise, M2 (R2 = 0.981) fitted better to Langmuir adsorption model. M3 presented the highest buffer and Cd retention capacity, possibly related to its clay content. Based on desorption studies, M3 presented the strongest binding site as 95% of metal removal was attributed to specific sorption. Silt loam is the most suitable soil coverage for industrial land of all analyzed soils.

Absorption capacity of hydromorphic soils in relation to heavy metal

Comparative studies of ion-exchange adsorption of Zn(II) and Cu(II) cations by hydromorphic soils of southern Russia have been performed. Various equations (Langmuir, Freundlich, and Dubinin-Radushkevich) were used and the adsorption parameters and adsorption energy were calculated to describe the obtained isotherms. A significant decrease of the distribution coefficient (Kd) with an increase of the metal concentration in an equilibrium solution was revealed. It is shown that the Langmuir equation and, to a lesser degree, the Dubinin-Radushkevich and Freundlich equations are the most suitable model to describe the adsorption processes of Zn(II) and Cu(II) by the soils in all experimental variants. The strong correlation between the parameters of the sorption of metals obtained using a particular chosen model was established. The Langmuir equation provides higher strengths of a bond than the Dubinin-Radushkevich equation. In all cases, the sorption capacity of meadow soil in relation to the studied metals is higher than for alluvial soil due to the low buffering capacity of the latter. Both types of soils characterize with higher affinity to Cu(II) than to Zn(II).

A new alternative of a green polymeric matrix chitosan/alginate-polyethyleniminemethylene phosphonic acid for pharmaceutical residues adsorption.

A new generation of a green polymeric matrix, chitosan/alginate-polyethyleniminemethylene phosphonic acid (CHIT/ALG-PEIMPA) was examined in comparative study of adsorption and preconcentration of non-steroidal anti-inflammatory drugs (NSAIDs), diclofenac and ibuprofen. The influences of experimental parameters like pH, time reaction, initial concentration, ionic strength were investigated. The scanning electron microscopy (SEM) images showed heterogeneous morphology with different particle sizes of agglomerates from few micrometers to a hundred micrometers and irregular particles shape, before pharmaceuticals products adsorption. However, after adsorption, SEM micrograph reveals a smooth surface structure of agglomerate, and even in this smaller magnification, it was possible to observe the formation of homogenous and regular surface of CHIT/ALG-PEIMPA. Elementary analysis (EDX) reveals that the phosphonic acid (PEIMPA) was successfully cross-linked onto chitosan/alginate. The maximal adsorption capacity was found to be 222 mg.g-1, and 122 mg.g-1 under optimum conditions for diclofenac and ibuprofen respectively. The kinetic modeling followed the pseudo-second-order rate expression for both pharmaceutical drugs. Thermodynamics data leads to an exothermic and spontaneous adsorption processes (∆H = -34.32 KJ mol-1; ∆H =-21.59 KJ mol-1), respectively for diclofenac and ibuprofen.

Comparative Study of Glyphosate Adsorption on Armchair CNT(5.5) and BNNT(5.5): A DFT Study

Detecting glyphosate is of great importance as it has been classified as a probable carcinogen. In literature, many nanotubes have been used to detect Glyp among them CNT. However, we did not found any study that used BNNT to detect it. So, in this work, we focus on performing a comparative study of the Glyp adsorption on CNT (5.5) and BNNT (5.5) using B3LYP, M06-2X, and B97X-D/6-31G(d) by first-principles calculations in the framework of Density Functional Theory. From our results, we conclude that the adsorption energies of BNNT (5.5)/Glyp are slightly higher than those calculated by CNT (5.5)/ Glyp and are in very close agreement with the NCI analyses. The thermodynamics parameters also showed that the two nanotubes could detect glyphosate with a physisorption process that was exothermic and thermodynamically favourable. Besides that, TDOS and QTAIM analyses revealed the non-covalent interaction between glyphosate and the two nanotubes.

Comparative adsorption studies of cadmium ions on phosphogypsum and natural clay

Cadmium ions pollution and waste resulting from industrial activities are classified as serious environmental problems. In this study, we performed comparative adsorption studies of cadmium (II) on phosphogypsum (PG) and natural clay (NC) from an aqueous solution. The difference in adsorption mechanisms between phosphogypsum and natural clay was inspected using scanning electron micrographs; X-ray diffraction and Fourier transform infrared. The effects of contact time and certain factors such as the adsorbent dosage and the pH of the solution were studied. The comparative study shows that the differences in adsorption behavior come from the chemical and structural differences of the adsorbents studied. It was found that 0.73 mg·g−1 is the maximum adsorption capacity for phosphogypsum, whereas for natural clay it was 5.65 mg·g−1. Cadmium (II) removal was pH-dependent and the optimum adsorptions of phosphogypsum and clay were found at pH basic. It has been confirmed that the pseudo-second order model is best suited to the kinetics of the process studied for the two adsorbents. Overall, natural clay is a better adsorbent than phosphogypsum and this latter can be used as a potential adsorbent candidate for the removal of Cd(II) from aqueous solutions.

Comparative DFT Study of 5-Fluorouracil Adsorption on Silica and Graphene for Bio-Medical Applications

Aims: The administration of antitumor 5-Fluorouracil (5-FU) into the human body is generally accomplished via a central venous catheter that is prone to degradation when it comes in contact with bodily fluids or aggressive drugs such as 5-Fu. Therefore, degradation could be reduced by applying protective coatings onto the internal and/or external surfaces of the catheters. Objectives: Graphene and silica materials could be promising coating materials because of their low reactivity and antimicrobial properties. The mechanisms of interaction between the carrier and the drug are based on surface chemistry related phenomena. Understanding the physicochemical features of the surfaces is a fundamental step to describe and predict the strength of these interactions and may result in controlled adsorption and release processes. Methods: Computational DFT methods can provide an important aspect by providing atomistic details of the drug adsorbed on the surfaces through molecular modeling. Results: DFT calculations of the binding energy, charge exchange and orbital population of 5-FU adsorbed on graphene and silica materials confirmed weak interactions between the drug and the solid surfaces that could favor desorption during the drug delivery. Graphene and silica surfaces do not react with the 5-FU molecule behaving as inert materials and the drug does not suffer from degradation nor alter its structure during adsorption on both the materials. Conclusion: These characteristics, in addition to biocompatibility and antimicrobial properties, suggest that graphene and silica could be used as promising internal/external coating materials for biomedical applications.

Comparative Study of CO2 Capture by Adsorption in Sustainable Date Pits-Derived Porous Activated Carbon and Molecular Sieve.

The rising CO2 concentration has prompted the quest of innovative tools to reduce its effect on the environment. A comparative adsorption study using sustainable low-cost date pits-derived activated carbon and molecular sieve has been carried out for CO2 separation. The adsorb ents were characterized for surface area and morphological properties. The outcomes of flow rate, temperature and initial adsorbate concentration on adsorption performance were examined. The process effectiveness was investigated by breakthrough time, adsorbate loading, efficiency, utilized bed height, mass transfer zone and utilization factor. The immensely steep adsorption response curves demonstrate acceptable utilization of adsorbent capability under breakthrough condition. The adsorbate loading 73.08 mg/g is achieved with an 0.938 column efficiency for developed porous activated carbon at 298 K. The reduced 1.20 cm length of mass transfer zone with enhanced capacity utilization factor equal 0.97 at 298 K with Cin = 5% signifies better adsorption performance for date pits-derived adsorbent. The findings recommend that produced activated carbon is greatly promising to adsorb CO2 in fixed bed column under continuous mode.

Batch Comparative Adsorption Studies of Fluoride Using Activated Carbon Derived from Magnifera Indica (Mango) Seeds and Peltophorum Pterocarpum (Copper Pod) Seeds

Activated Carbon (AC) is frequently used for purification due to its ability to remove pollutants either from air or water. Its porous structure allowed it to capture pollutants and is widely recommended for numerous applications in water and wastewater treatment. However, AC applications fields are restricted due to high costs. In this project, AC was prepared from locally available Magnifera Indica (Mango) seeds and Peltophorum Pterocarpum(Copper Pod) seeds. The removal of Fluoride from the synthetic sample by adsorption on physically activated carbon prepared from Magnifera Indica (Mango) seeds and Peltophorum Pterocarpum(Copper Pod) seeds have been carried out at room temperature 32 ± 1oC. Batch adsorption processes were conducted for the removal of Fluoride on physically activated carbon for optimum time, optimum dosage, optimum pH sorption kinetics sorption equilibrium. The optimum contact time, adsorbent dose, and pH for carbon was 35 min, 100 mg and 8.00 and 40min, 160mg and 8.50 respectively, with a fluoride removal efficiency of 78.96%, 96%, 97% and 45%, 58%, 96% respectively have been observed. Adsorption kinetics and sorption isotherm models were studied by altering different process parameters like adsorption time and dosage respectively. Langmuir, Freundlich, and Temkin isotherms are studied through this experimental data and found to be well followed.

A Comparative Study of Oxygen and Hydrogen Adsorption on Strained and Alloy-Supported Pt(111) Monolayers

A comparative study of the unreacted and reacted uniaxially strained Pt(111) and the layered (111)-Pt/Ni/Pt3Ni and (111)-Pt/Ni/PtNi3 surfaces has been performed using density functional theory (DFT). An in-depth study of the unreacted surfaces has been performed to evaluate the importance of geometric, magnetic and ligand effects in determining the reactivity of these different Pt surfaces. An analysis of the binding energies of oxygen and hydrogen over the high-symmetry binding positions of all surfaces has been performed. The study has shown that O and H tend to bind more strongly to the (111)-Pt/Ni/Pt3Ni surface and less strongly to the (111)-Pt/Ni/PtNi3 surface compared to binding on the equivalently strained Pt(111) surfaces. Changes in the surface magnetisation of the surfaces overlaying the ferromagnetic alloys during adsorption are discussed, as well as the behaviour of the d-band centre across all surfaces, to evaluate the potential mechanisms for these differences in binding. An accompanying comparison of the accessible density functionals has been included to estimate the error in the computational binding energies.

Kinetics and isotherms of lead ions removal from wastewater using modified corncob nanocomposite

A promising new eco-friendly sorbent from agricultural waste (silica/corncob nanocomposite) was successfully prepared and used for the removal of lead ions from the solution. The characterization and identification of the synthesized sorbents were investigated using different techniques. A comparative adsorption study between two sorbents was estimated to identify the best efficient sorbent. The potential of the best sorbent to remove lead ions (Pb2+) from an aqueous solution was investigated in batch experiments, where several parameters such as contact time, pH, sorbent dose, and initial concentration of Pb2+ ions were investigated. For deep information, Kinetic and isotherm models were applied for sorption. Furthermore, the column study was evaluated from silica/corncob nanocomposite for removal of Pb2+ ions and the potential ability of the synthetic nanocomposite to be regenerated and reuse was also studied. It is remarkable that with 0.3 g of silica/corncob nanocomposite, up to 95% of Pb2+ could be removed at pH = 5.5 after 60 min which is higher than corncob (77%). From the kinetics and isotherms data, the harmony of data was fitted with the pseudo-second-order kinetic model and the Langmuir isotherm model. From a single column results, it seems that silica/corncob nanocomposite has proven to be a promising material and economical for the removal of heavy metals. Moreover, the results showed that the removal efficiency for Pb2+ was more than 90% for the first two cycles, and then slightly decreased to 85%. So, the silica/corncob nanocomposite can be reused for the removal of heavy metals from wastewater for at least 3 cycles.

Comparative study for adsorption of congo red and methylene blue dye on chitosan modified hybrid nanocomposite

The present paper reports the synthesis of an eco-friendly and low-cost chitosan modified hybrid Azadirachta indica leaves powder-Kaolinite clay (Chit/AILP-Kao) nanocomposite and further explored as a potential adsorbent to remove hazardous congo red (CR) and methylene blue (MB) dyes from aqueous solution. The optimum pH for the sequestration of CR and MB dye were found to be 6 and 7 respectively. Among the evaluated isotherms, equilibrium data was found to be the best fitted by Langmuir model on the basis of higher value of coefficient R2 (0.998). The maximum monolayer adsorption capacity (qm) for CR and MB dyes were found to be 104.6, 99.01 mgg−1 respectively at optimum pH and temperature 30 °C. To determine the adsorption process kinetic model was best obeyed by pseudo second order on the basis of higher value of coefficient R2 (0.998). In the thermodynamic parameters, negative values of ΔG° and positive values ΔHo confirms the spontaneous and endothermic nature of adsorption process. The values of maximum specific surface area for CR dye was found to be 210.7 m2 g-1 while for MB dye it was 223.7 m2 g-1. The regeneration study confirmed that the present nanocomposite can be regenerated upto fifth cycle successfully.

A comparative study for phosphate adsorption on amorphous FeOOH and goethite (α-FeOOH): An investigation of relationship between the surface chemistry and structure

Eutrophication is generally caused by excess nitrogen and phosphorus being released into surface waters by runoff. Developing adsorbents for adsorbing phosphate within soil buffer zones and/or water treatment columns may be effective methods to mitigate this problem. In this study, an amorphous FeOOH (AF) and a well-crystallized α-FeOOH (CF) was formulated to compare phosphate adsorption behavior. The physicochemical properties between these species showed significant differences in morphology, crystallization, zeta potential, and specific surface area. The AF exhibited higher phosphate uptake than CF. X-ray photoelectron spectroscopy (XPS) verified that the hydroxyl groups within AF were 13.28% higher than that in CF. The triply coordinated hydroxyl groups (μ3-OH) associated with AF and CF appeared at different positions as shown in the diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) analyses, confirming that AF contains more adsorption reactive sites (μ3-OH). Mechanisms for monodentate formations and a stable six-member ring structure were proposed. The X-ray absorption near the edge structure (XANES) and XPS results suggested that the iron valence in AF was dominated by Fe (III). XANES also demonstrated that the amorphous structure found in the AF was caused by the disordered tetrahedron and octahedron alignments, leading to a higher phosphate adsorption.

Comparative study of methylene blue adsorption using alkali-activated pumice from Bali and Banten

This study presents the comparison of methylene blue (MB) adsorption using alkali-activated pumice from Bali (A-P1) and Banten (A-P2). Pumice samples were activated under alkaline solution and followed by simple hydrothermal treatment in a polypropylene bottle at 100 °C for 24 hours. The X-ray diffraction (XRD) patterns showed that both treated pumices have different peak characteristics, where only A-P1 was dominated by the mineral phase of GIS-NaP1 zeolite. The change of amorphous to zeolite phases increased negative sides and caused A-P1 to have a higher adsorption capacity than A-P2. Based on the adsorption data of AP1 and AP2, the Langmuir isotherm model shows a better fit with high correlation values (R2) compared to the Freundlich model. This means the interaction between the treated pumice and MB followed the assumption of monolayer coverage on homogeneous surfaces, in which the maximum values of MB adsorption were found to be 51.546 mg/g for A-P1 and 27.027 mg/g for A-P2. In addition, A-P1 and A-P2 were also potentially used as heterogeneous catalysts for MB degradation through Fenton-like process due to the presence of iron oxide contents.

Comparative Evaluation of Different MOF and Non‐MOF Porous Materials for SO2 Adsorption and Separation Showing the Importance of Small Pore Diameters for Low‐Pressure Uptake

AbstractThe search for adsorbents for flue gas desulfurization processes is a current interest. For the first time, a comparative experimental study of SO2 adsorption by porous materials including the prototypical metal–organic frameworks NH2‐MIL‐101(Cr), Basolite F300 (Fe‐1,3,5‐BTC), HKUST‐1 (Cu‐BTC), the zeolitic imidazolate frameworks (ZIF)‐8, ZIF‐67, the alumosilicate Zeolite Y, the silicoaluminumphosphate (SAPO)‐34, Silica gel 60, the covalent triazine framework (CTF)‐1, and the active carbon Ketjenblack is carried out. Microporous materials with pore sizes in the range of 4–8 Å or with nitrogen heterocycles are found to be optimal for SO2 uptake in the low‐pressure range. The SO2 uptake capacity at 1 bar correlates with the Brunauer‐Emmett‐Teller‐surface area and pore volume rather independently of the surface microstructure. Zeolite Y and SAPO‐34 are stable toward humid SO2. The materials Zeolite Y and CTF‐1(600) show the most promising SO2/CO2 selectivity results with an ideal adsorbed solution theory selectivity in the range of 265–149 and 63–43 with a mole fraction of 0.01–0.5 SO2, respectively, at 293 K and 1 bar.

Comparative study of dye adsorption onto CNT/PVDF and reduced rGO/PVDF membranes post-treated by a swelling and freeze-drying process

Comparative study of dye adsorption onto CNT/PVDF and reduced rGO/PVDF membranes post-treated by a swelling and freeze-drying process

Lithium and sodium intercalation in a 2D NbSe2 bilayer-stacked homostructure: comparative study of ionic adsorption and diffusion behavior.

In this work, we probed the lithium and sodium intercalation properties in monolayer-stacked NbSe2 bilayer homostructure configurations for their potential application as anode materials in lithium and sodium ion batteries. Similar to known monolayer transition metal dichalcogenides, such as VS2, the structural phase transition barrier of NbSe2 from 1H to 1T is strengthened by lithium and sodium adsorption, implying that it is robust under multiple charging and discharging processes. As multi-layer, stacked 2D materials are more relevant to experiments and their intended applications, four bilayer homostructure stackings were constructed based on the alignment of Nb and Se. All four bilayer homostructure stackings were found to significantly enhance the binding of lithium and sodium at the van der Waals interface, and thus potentially increase the theoretical specific energy capacity of NbSe2via bilayer stacking. In terms of ionic diffusion, it is observed that for all of the bilayer homostructure configurations the diffusion energy barrier for lithium and sodium generally increased compared to the monolayer case. The nature of the stacking appears to affect the diffusion energy barrier with a value of as high as 1.94 eV in the case of sodium for the AB full stacking (compared to 0.08 eV for the monolayer). It is inferred that although the bilayer homostructure stacking of NbSe2 could significantly increase the theoretical specific energy capacity for both lithium and sodium, its drawback is the slowing down of the ion kinetics at the van der Waals interface, which are also important in the charging and discharging processes of a battery system.

A comparative study of adsorption of heavy metals by graphene oxide and cellulose hydrogel composites

A comparative study of adsorption of heavy metals by graphene oxide and cellulose hydrogel composites