Adsorption of phenol and o-chlorophenol by mesoporous MCM-41.
ABSTRACT Water pollution by toxic organic compounds is of concern and the demand for effective adsorbents for the removal of toxic compounds is increasing. Present work deals with the adsorption of phenol (PhOH) and o-chlorophenol (o-CP) on mesoporous MCM-41 material. The effect of surfactant template in MCM-41 on the removal of PhOH and o-CP was investigated. The comparison of adsorption of PhOH and o-CP on uncalcined MCM-41 (noted as MCM-41) and calcined MCM-41 (noted as C-MCM-41) was investigated. It was found that MCM-41 shows significant adsorption for PhOH and o-CP as compared to C-MCM-41, this may be because of the hydrophobicity created by surfactant template in the MCM-41. Batch adsorption studies were carried out to study the effect of various parameters like adsorbent dose, pH, initial concentration and the presence of co-existing ions. It was found that adsorption of PhOH and o-CP depends upon the solution pH as well as co-existing ions present in the aqueous solution. The equilibrium adsorption data for PhOH and o-CP was analyzed by using Freundlich adsorption isotherm model. From the sorption studies it was observed that the uptake of o-CP was higher than PhOH.
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ABSTRACT: Immobilization of biological macromolecules, such as protein, onto solid supports is an important method for diagnostic assays andgenetechnology. This present study reports the size-selective adsorption/removal of virtual proteins that have different shapes, sizes, functions, and properties, such as insulin, cytochrome c, lysozyme, myoglobin, β-lactoglobin, α-amylase, hemoglobin, and myosin in aqueous water using mesobiocaptor monoliths. To prevent large proteins from adsorbing and remaining attached to adsorbent surfaces, large, open, cylindrical-pored, three-dimensional cubic aluminosilica mesostructures with large aluminum contents and micrometer-sized monolith particles were fabricated. The unique physical properties and the surface functionality of the mesobiocaptors enhance protein adsorption characteristics in terms of loading capacity and quantity of the sample, ensuring a higher concentration of adsorbed proteins, interior pore diffusivity, and encapsulation in a short period. Thermodynamic studies indicate that protein adsorption into the mesobiocaptor pores is favorable and spontaneous. Theoretical models were used to investigate the major driving forces for the most optimal performance of the protein adsorption. The geometrical findings point to key factors, such as surface energy, intermolecular forces, charge distribution, hydrophobicity, and electrostatic interaction, which might control the adsorption into the interior large, open cylindrical mesobiocaptor cavities (sized 3–16 nm) without aggregation of these proteins on the exterior surfaces of monoliths. Indeed, the availability of adsorption of single proteins from mixtures based on size- and shape-selective separation opens new avenues of research in encapsulation of proteins and bioanalysis.Advanced Functional Materials 07/2012; 22(14). · 10.44 Impact Factor
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ABSTRACT: This tutorial review will focus on the removal of organic pollutants from the aqueous phase by mesoporous silica. After a brief discussion about mesosilica formation (MCM-41 and SBA-15) and silica surface modification, the review will focus on the use of mesosilica for the removal of (i) organic compounds, (ii) organic dyes, or (iii) pharmaceuticals from aqueous solutions.Chemical Society Reviews 04/2014; · 30.43 Impact Factor
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ABSTRACT: In this work we are reporting the adsorption capacity of silica and silicalita-1 derivatives from the rice hull ashes. We show the possibility to use these materials in the pollution control. Silica from rice hull ashes showed a good capacity to fix Cd 2+ , although Ca 2+ was present in concentrations considerably higher than Cd 2+ . On the other hand Silicalite-1 appears to be a competitive adsorbent of para-chorophenol.