Journal of Encapsulation and Adsorption Sciences

Journal Information
ISSN / EISSN : 2161-4865 / 2161-4873
Current Publisher: Scientific Research Publishing, Inc. (10.4236)
Total articles ≅ 116
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Shenggen Wu, Xiaoli Liang, Qi Zhang, Guiru Zhang
Journal of Encapsulation and Adsorption Sciences, Volume 11, pp 1-17; doi:10.4236/jeas.2021.111001

Abstract:
It is urgent to develop excellent solid CO2 sorbents with higher sorption capacity, simpler synthetic process, better thermal stability and lower costs of synthesis in CO2 capture and storage technologies. In this work, a number of Li4SiO4-based sorbents synthesized by lithium carbonate with three different kinds of fly ashes in various molar ratios were developed. The results indicate that the Li2CO3:SiO2 mole ratio used in the sorbents synthesis significantly affects the CO2 absorption properties. The sorption capacity increased with the excess of Li2CO3 first and then decreased when the excessive quantity was beyond a certain amount. The experiments found that FA-Li4SiO4_0.6, CFA-Li4SiO4_0.4, HCl/CFA-Li4SiO4_0.3 presented the best sorption ability among these fly ash derived Li4SiO4 samples, and the corresponding weight gain was 28.2 wt%, 25.1 wt% and 32.5 wt%, respectively. The three sorbents with the optimal molar ratio were characterized using various morphological characterization techniques and evaluated by thermogravimetric analysis for their capacity to chemisorb CO2 at 450°C - 650°C, diluted CO2 (10%, 20%) and in presence of water vapor (12%). The adsorption curve of FA- Li4SiO4_0.6 at different temperatures was simulated with the Jander-Zhang model to explore the influence of carbon dioxide diffusion on adsorption reaction. Further experiments showed that the adsorbent had a good sorption capacity in a lower partial pressure of CO2 and the presence of steam enhanced the mobility of Li+. What’s more, FA-Li4SiO4_0.6, CFA-Li4SiO4_0.4 and HCl/CFA-Li4SiO4_0.3 particles showed satisfactory sorption capacity in fixed-bed reactor and excellent cyclic sorption stability during 10 sorption/ desorption cycles.
Drissa Ouattara Kra, Grah Patrick Atheba, N’Da Arsène Kouadio, Patrick Drogui, Albert Trokourey
Journal of Encapsulation and Adsorption Sciences, Volume 11, pp 18-43; doi:10.4236/jeas.2021.111002

Abstract:
The objective of this study is to develop carbon, that of Acacia auriculeaformis through its activation in order to eliminate lead in an aqueous medium. A series of activated carbon has been prepared by chemical activation with phosphoric acid, sodium hydroxide and sodium chloride. The determination of the physico-chemical properties of the prepared carbon guided the choice of phosphoric acid activated carbon as the best adsorbent for the elimination of lead(II) in an aqueous solution. Pb2+ adsorption tests in batch mode have shown that the adsorption capacity is influenced by various parameters such as mass, pH, concentration of Pb2+ ions and contact time linked to the medium and the adsorbent. Adsorption isotherms, kinetic models and thermodynamics have been used to describe the adsorption process. The equilibrium data for activated charcoal correspond well to the model of Freundlich, Langmuir, Temkin and Kiselev. The kinetic adsorption data proved to be better described by the pseudo-second order model with external and intraparticle diffusion which are two decisive steps in the adsorption process of Pb2+ ions. Thermodynamics and adsorption isotherms predict a spontaneous exothermic surface reaction, of the chemisorption type, with ion retention in orderly monolayers on the heterogeneous surface of the adsorbent. Tests carried out with this adsorbent material have contributed to the elimination of the Pb2+ ions contained in an industrial effluent with a reduction rate reaching 42.52% against 85.90% in a synthetic solution.
Juan C. Manrique-Arias, Quetzali Pitalua-Cortes, Roberto Pedrero-Piedras, Géiser Rodríguez-Mena, Tessy López, Cristian Cabezas-Ortiz, Osvaldo García-Pérez
Journal of Encapsulation and Adsorption Sciences, Volume 10, pp 29-41; doi:10.4236/jeas.2020.102002

Abstract:
This Bombesin (BBN), a tetradecapeptide analog of human gastrin-releasing peptide (GRP) with a high binding affinity for GRP receptors (GRPR), is over- expressed in early stages of androgen-dependent prostate carcinomas, but not in advanced stages. Therefore, there is a need to develop effective tracers for the accurate and specific detection of this disease. The objective of this study was to evaluate Lys1, Lys3-DOTA-BBN (1,14) analog with the radiolabeled positron emitter [68Ga]-Ga-BBN for receptor imaging with PET, and to determine its biodistribution and radiation dosimetry using whole-body (WB) PET scans in healthy volunteers. The highest uptake was in the pancreas, followed by urinary bladder. The critical organ was pancreas with a mean absorbed dose of 206 ± 0.7, 210 ± 0.7, 120 ± 0.9, 390.23 ± 0.6 μGy/MBq and the effective doses were estimated as 73.2 ± 0.6, 49.8 ± 0.3 μGy/MBq (women and men, respectively).
Tiotsop Kuete Idris-Hermann, Raoul Tchuifon Tchuifon Donald, Nche Ndifor-Angwafor George, Tamo Kamdem Arnaud, Gabche Anagho Solomon, Idris-Hermann Tiotsop Kuete, Donald Raoul Tchuifon Tchuifon, George Nche Ndifor-Angwafor, Arnaud Tamo Kamdem, Solomon Gabche Anagho
Journal of Encapsulation and Adsorption Sciences, Volume 10, pp 1-27; doi:10.4236/jeas.2020.101001

Abstract:
In this work, activated carbons (ACs) prepared by chemical activation of garcinia cola nut shell impregnated with H3PO4 (CBH2/1) and KOH (CBK1/1) were used to study the kinetics, equilibrium and thermodynamics of the adsorption of thymol blue from aqueous solution. The characterization of ACs showed the BET measurements gave surface area and total pore volume respectively of 328.407 m2·g-1 and 0.1032 cm3·g-1 for CBH2/1 and 25.962 m2·g-1 and 0.03 cm3·g-1for CBK1/1; elemental analysis showed a high percentage of carbon in both ACs. Influence of parameters such as initial pH, contact time, adsorbent mass, initial concentration, ionic strength and the effect of temperature on the removal of thymol blue from aqueous solution were studied in batch mode. The studies showed that equilibrium adsorption was attained after 60 minutes for the two ACs, adsorption capacity increased with increasing concentration of thymol blue, and maximum adsorption capacity was obtained at an acidic environment with pH 2. Avrami’s non-linear kinetic expression was the best suited for describing the adsorption kinetics of thymol blue onto ACs, while equilibrium data showed that the three-parameter isotherms better described the adsorption process since R2 > 0.96, and the error functions were lowest for all of them. Maximum adsorption capacity values obtained using the three-parameter Fritz-Schlunder equation were 32.147 mg·g-1 for CBH2/1 and 67.494 mg·g-1 for CBK1/1. The values of the model parameters g and mFS respectively, obtained using the Redlich-Peterson and Fritz-Schlunder III isotherms below 1, showed that the adsorption of thymol blue by the ACs occurred on heterogeneous surfaces. Thermodynamic analyses of the data of the adsorption of thymol blue onto ACs revealed that the adsorption process was temperature dependent, endothermic and spontaneous. This electronic document is a “live” template. The various components of your paper [title, text, heads, etc.] are already defined on the style sheet, as illustrated by the portions given in this document.
Erdener Karadağ, Belgin Yel, Semiha Kundakcı, Ömer Barış Üzüm
Journal of Encapsulation and Adsorption Sciences, Volume 10, pp 43-70; doi:10.4236/jeas.2020.103003

Abstract:
Novel sorbent hydrogels containing acrylamide/sodium vinylsulfonate, carboxymethyl cellulose and zeolite were synthesized with free radical solution polymerization by using ammonium persulfate/N,N,N’,N’-tetramethylethyle-nediamine as redox initiating pair in presence of poly(ethylene glycol) diacrylate as crosslinker. It was to investigate the water uptake properties of series of the novel hydrogels, the semi IPNs and the hybrid/biohybrid composite hydrogel sorbents synthesized in this study. Water uptake studies were performed in water and in water-solvent (acetone, methanol and tetrahydrofuran) binary mixtures at 25°C, gravimetrically. Some swelling and diffusion parameters were calculated and discussed. It has been seen that the lower equilibrium swelling factor values in all solvent compositions in comparison with the equilibrium swelling factor values in water.
Godfrey Musumba, Caroline Nakiguli, Cranmer Lubanga, Paul Mukasa, Emmanuel Ntambi
Journal of Encapsulation and Adsorption Sciences, Volume 10, pp 71-84; doi:10.4236/jeas.2020.104004

Abstract:
Many science-based institutions in most developing countries use heavy metal containing salts in practical teaching sessions. The commonly used chemicals are the salts of lead (II) and copper (II) and the wastes generated end up into the environment when untreated. Thus, a study was done to remove lead (II) and copper (II) ions from mono synthetic aqueous solution using bio-char from Ficus natalensis fruits (FNF). This was done at varied pH, contact time, temperature, bio-char dosage level, salinity and metal ion concentration using the batch approach. The residual metal concentrations were determined using the atomic absorption spectrophotometer. The optimum pH for the adsorption of copper (II) and lead (II) ions was found to be 4.0 and 5.0 respectively. The maximum percentage adsorption of copper (II) and lead (II) by the FNF bio-char was established at 60 minutes contact time, 47.5°C and 0.4 g adsorbent dose. Increase in the metal ion concentration and the presence of interfering ions in the aqueous solution lead to decrease in the percentage adsorption. The highest adsorption capacity was found to be 161.29 mg/g and 1250 mg/g for copper (II) and lead (II) ions respectively. The thermodynamic parameters indicated the feasibility of the adsorption of copper (II) and lead (II) on the bio-char of FNF. Thus, bio-char from FNF may be used as an adsorbent in waste management where copper (II) and lead (II) ions are present at a concentration range of between 5 and 100 mg/l.
Salis Ibrahim, Steve Bowra
Journal of Encapsulation and Adsorption Sciences, Volume 9, pp 83-108; doi:10.4236/jeas.2019.92005

Abstract:
Polyphenolic compounds with relatively high antioxidant activity obtained from subcritical water extraction of apple pomace were assessed for encapsulation by spray drying technique, making use of polymeric substances co-extracted with the polyphenolic compounds. Comparative assessments were carried out of the directly encapsulated subcritical water extract (SWE) products with particles formed when encapsulated with the addition of hydroxyl propyl-β-Cyclodextrin (SWE + HPβ-CD). The powders were characterized for their physico-chemical properties such as, moisture content, density, particle size, hygroscopicity to assess their suitability within cosmetic formulations. The SWE and SWE + HPβ-CD encapsulated products resulted in different physical properties. Although the particle size was less than 4 μm for both products, the direct encapsulation (SWE) was highly hygroscopic and this property was significantly reduced with addition of HPβ-Cyclodextrin (SWE + HPβ-CD). Scanning electron microscopy (SEM) and Fourier Transform Infrared (FT-IR) spectroscopic were em-ployed to analyse the micronised powders to support evidence of encapsulation. Both techniques revealed the interaction between compounds in extract and the carrier HPβ-Cyclodextrin suggesting successful encapsulation. The effect of storage conditions on retention of antioxidant activity of the subcritical water extract was evaluated within 35 days for extracts with and without the carrier HPβ-Cyclodextrin. Hydroxyl propyl-β-Cyclodextrin offered protection against degradation of antioxidant compounds thereby potentially extending the shelf-life and making the encapsulated powder suitable for incorporation in cosmetic and pharmaceutical applications.
Mohamed S. Thabet
Journal of Encapsulation and Adsorption Sciences, Volume 9, pp 1-12; doi:10.4236/jeas.2019.91001

Abstract:
Polyoxometalate (POM) catalysts with different trivalent hetero ions (Mn+ = Fe3+, Al3+, and Cr3+) were prepared by incipient wetness impregnation method and supported on different zeolites namely, NaY, ZSM-5 and Mordenite. The intended catalysts samples were distinguished by X-ray diffraction, FTIR and surface texture measurements. The data given disintegration in the crystallinity of zeolite structure, enlarge in particle size and new phases of metal oxides Al2(MoO4)3 and Fe2(MoO4)3 were exposed by XRD and FTIR techniques. These phases caused widening of pores of the employed zeolites and change of the surface texture. The physical changes indicate the considerable interaction of polyoxomolybdate with the zeolite structure. The assessment of the catalytic activity was thorough by applied the photocatalytic degradation of direct blue 1 dye (DB1) in existence of H2O2 as a green oxidant. The catalytic activity of Mn+Mo-ZSM-5 sample is higher than that of Mn+Mo-Y or Mn+Mo-Mord.
Kamoru A. Salam
Journal of Encapsulation and Adsorption Sciences, Volume 9, pp 13-34; doi:10.4236/jeas.2019.91002

Abstract:
Effluents containing inorganic contaminants are releasing into the environment untreated despite being hazardous to man and environment. It is costly and unsustainable to use conventional methods to remove them from dilute aqueous solution. Adsorption involving granular activated carbon is an alternative method for treating such effluents. Granular activated carbon is structurally strong, highly resistance to attrition and wearing, large and can easily separate from the effluents. However, its surface is highly hydrophobic and has little surface charge thereby reducing its adsorption capacity for anion or cation. This article reviews surfactant modification of activated carbon to enhance its adsorption capacity for inorganic contaminants and key factors affecting the adsorption efficiency. They include initial concentration of contaminants, contact time, solution pH, solution temperature, adsorbent concentration, ionic strength, competing ions, type of surfactant, and surfactant concentration. The modified activated carbon usually shows maximum contaminant uptake around its critical micelles concentration. Surfactant modification reduces specific surface area and/or micro pore volume but hot NaOH or HNO3 treatment before surfactant modification minimises this drawbacks and increases the net surface charge. Overall, surfactant modification is a simple but efficient method of enhancing adsorption capacity of activated carbon for removing anion or cation from aqueous solution. However, a handful publication is available on the regeneration of the spent (saturated) surfactant modified activated carbons. Hence, more research efforts should be directed towards proper regenerating reagents and the optimise conditions such as contact time, concentration, and temperature for regenerating spent modified activated carbons.
Drissa Ouattara Kra, N’Guadi Blaise Allou, Patrick Atheba, Patrick Drogui, Albert Trokourey
Journal of Encapsulation and Adsorption Sciences, Volume 9, pp 63-82; doi:10.4236/jeas.2019.92004

Abstract:
The objective of this work is to prepare one of the best activated carbon (CA) based on wood (Acacia auriculeaformis). The chemical activation method was used for varying the chemical agent namely phosphoric acid H3PO4 (CAA), sodium hydroxide NaOH (CAB), and sodium chloride NaCl (CAS). The physico-chemical analysis of the three activated carbons indicated that, under the conditions of preparation, the activated carbons possess activation efficiencies lower than 50% (41.81% for CAA, 26.25% for CAB and 48.87% for CAS), low ash content (CAA: 5.00%, CAB: 14.90 and CAS: 6.60%) and iodine values ranging from 190.35 mg/g to 380.71 mg/g, suggesting that the good quality of the prepared activated carbon. The surface functional groups using Boehm test and the zero point charge (pHZPC) methods confirmed the acidic, basic and neutral character for CAA, CAB and CAS respectively (CAA: pHZPC = 4.8, CAB: pHZPC = 8.2, CAS: pHZPC = 6.8). The surface specific areas were determined through the liquid phase adsorption of acetic acid and methylene blue using the Langmuir method and BET analysis. Also, the porosity was determined. The BET surface areas of CAA, CAB and CAS were respectively 561.60 m2/g, 265.00 m2/g and 395.40 m2/g. The influence of chemical activation agent on pores formation was confirmed by scanning electron microscopic (SEM) analysis. CAA was selected as the best activated carbon because of its good surface area and good pore volume compared to those found in the literature. Therefore, its application as an adsorbent for effluents treatment could be explored. In addition, the best activating agent for coal from Acacia auriculeaformis was found to be phosphoric acid.
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