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Mavrikos A, Papoulis D, Todorova N, Papailias I, Trapalis C, Panagiotaras D, Chalkias D, Stathatos E, Gianni E, Somalakidi K, Sygkridou D, Komarneni S. Synthesis of Zn/Cu metal ion modified natural palygorskite clay – TiO2 nanocomposites for the photocatalytic outdoor and indoor air purification. J Photochem Photobiol A Chem 2022. [DOI: 10.1016/j.jphotochem.2021.113568] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abd-El-Raoof F, Tawfik A, Komarneni S, Ahmed S. Hydrotalcite and hydrocalumite as resources from waste materials of concrete aggregate and Al-dross by microwave-hydrothermal process. Construction and Building Materials 2019; 207:10-16. [DOI: 10.1016/j.conbuildmat.2019.02.105] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Affiliation(s)
- J.P. Cheng
- Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - D.K. Agrawal
- Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - S. Komarneni
- Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - M. Mathis
- Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
| | - R. Roy
- Materials Research Laboratory, The Pennsylvania State University, University Park, PA 16802, USA
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Tawfik A, Abd El-Raoof F, Katsuki H, MacKenzie KJ, Komarneni S. K-Based Geopolymer from metakaolin: roles of K/Al ratio and water or steam Curing at different temperatures. Mater construcc 2016; 66:e081. [DOI: 10.3989/mc.2016.03115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Seliem MK, Komarneni S, Parette R, Katsuki H, Cannon FS, Shahien MG, Khalil AA, El-Gaid IMA. Composites of MCM-41 silica with rice husk: hydrothermal synthesis, characterisation and application for perchlorate separation. ACTA ACUST UNITED AC 2013. [DOI: 10.1179/143307510x12820854749312] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Affiliation(s)
- M. K. Seliem
- Materials Research InstituteMaterials Research Laboratory, The Pennsylvania State University, University Park, PA 16802 , USA, Geology Department, Faculty of Science, Beni-Sueif University, Beni-Sueif, Egypt
| | - S. Komarneni
- Materials Research InstituteMaterials Research Laboratory, The Pennsylvania State University, University Park, PA 16802 , USA ;,
| | - R. Parette
- Matson & Associates Inc. , 331 East Foster Ave., State College, PA 16801 , USA
| | - H. Katsuki
- Saga Ceramics Research Laboratory , 3037-7 , Arita-machi, Saga 844-0022 , Japan
| | - F. S. Cannon
- Department of Civil and Environmental EngineeringThe Pennsylvania State University, University Park, PA 16802 , USA
| | - M. G. Shahien
- Geology DepartmentFaculty of Science, Beni-Sueif University, Beni-Sueif, Egypt
| | - A. A. Khalil
- RefractoriesCeramics and Building Materials Department, National Research Center, Dokki, Cairo, Egypt
| | - I. M. Abd El-Gaid
- Geology DepartmentFaculty of Science, Beni-Sueif University, Beni-Sueif, Egypt
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Seliem MK, Komarneni S, Byrne T, Cannon F, Shahien M, Khalil A, Abd El-Gaid I. Removal of nitrate by synthetic organosilicas and organoclay: Kinetic and isotherm studies. Sep Purif Technol 2013. [DOI: 10.1016/j.seppur.2013.03.023] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Abstract
ABSTRACTTruly nanocomposite materials that are stable to about 400 to 700°C can be prepared by intercalating oxides or metal clusters of about 0.4 to 2.0 nm in between ∼1.0 nm layers of smectite clays. Both the chemistry and size of intercalates (pillars) can be varied to introduce unique catalytic, molecular sieving, dehumidifying and adsorption properties in these materials. The intercalated clays also provide opportunities to prepare compositionally and stoichiometrically diverse nanocomposite precursors to high temperature structural and electronic ceramics. Although montmorillonite is the most widely used host, further designing in properties can be achieved by using other members of smectite family having subtle crystal chemical and compositional variations, such as beidellite, nontronite, saponite or hectorite. The sol-gel chemistry involving the preparation of positively charged mono- or multiphasic solution-sol or colloidal-sol particles is a viable approach to introduce chemically diverse oxide particles in the interlayers of smectite. Reduction of transition metal ions or complexes in the interlayers of smectite to zerovalent metal clusters/particles using polar liquids is another novel approach to develop catalytically active, high surface area materials.
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Abstract
AbstractA series of microporous silica gels were synthesized by hydrolyzing tetramethylorthosilicate (TMOS) with varying amounts of water. No catalyst or alcohal was added. The gels were characterized by water sorption isotherms, the BET nitrogen surface area measurements, and differential thermal analysis. Although the gelation time for all H2O/TMOS molar ratios (R) was approximately the same (about 3 hr), the pore-size (pore diameter) and sorption capacity were found to be minimum in the R range 4.96–5.37 but increased with both increasing and decreasing R. Water sorption isotherms measured at 25°C after degassing at 200°C of gels prepared with R = 4.96–5.37 exhibited moderate Type I (Brunauer classification) isotherm which changed to intermediate between Type I and Type IV with decreasing or increasing R. These results indicated that the amount of organic or water which was not utilized in the reaction and the degree of cross-linking apparently played a role for the observed variations in pore-size or shape of water isotherms.
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Malla PB, Komarneni S. Synthesis And Water Sorption Properties Of Aluminophosphate (AlPO4) And Silicoaluminophosphate (Sapo) Molecular Sieves. ACTA ACUST UNITED AC 2011. [DOI: 10.1557/proc-233-237] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
ABSTRACTAluminophosphate (AlPO4–5, AlPO4–11, AlPO4–17, AlPO4–20) and silicoaluminophosphate (SAPO-5, SAPO- 11, SAPO-17, SAPO-20) molecular sieves of varying pore sizes (3–8 Å) were synthesized and their water adsorption and desorption properties were studied. Water sorption isotherms of AlPO4 molecular sieves were characterized by unusual isotherm shapes, that is, little or no initial adsorption followed by extreme adsorption leading to volume filling by hydrogen bonding and cooperative interaction in micropores, apparently due to the nonpolar nature of pore surfaces coupled with weak (reversible upon evacuation) chemisorption of water, and hysteresis loops extending to very low pressures. Although micropore filling in AlPO2's and isostructural SAPO's was completed almost at the same relative pressure (p/po), SAPO's exhibited less extreme adsorption isotherms as a result of their slightly more polar nature of pore surfaces compared to AlPO4's. Neither AlPO4apos;s nor SAPO's exhibited Brunauer Type I isotherms with water, contrary to a general expectation of the hydrophilic microporous solids.
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Abstract
ABSTRACTInstead of aiming to prepare homogeneous gels and xerogels, this paper reports on work done to prepare deliberately diphasic materials. This has been achieved by three different paths: (1) mixing 2 sols; (2) mixing 1 sol with 1 solution; and (3) post formation diffusion of either one or two solutions.By the last named process we have made SiO2, mullite and alumina based composites, with silver halides, BaSO4, CdS, etc., as the dispersed phase. The crystal size can be confined to the initial pores by rapid diffusion giving rise to extremely fine second phases in the submicron range. Subsequent reduction of appropriate metallic salts can be used to give finely dispersed metals (e.g. Cu, Ni) in essentially any xerogel matrix. The open porosity makes these metal atoms very accessible.By the first two processes we have made both single phase and di-phasic gels of the same composition (prototype: mullite) and shown that though they cannot be distinguished by XRD, SEM, and TEM, by DTA and thermal processing, they are radically different. Such di-phasic gels store more metastable energy than any other solids.
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Seliem MK, Komarneni S, Park M, Katsuki H, Shahien M, Khalil A, Abd El-Gaid I. Hydrothermal synthesis of Mn-kaolinite using NaOH or KOH and characterization. Applied Clay Science 2010; 49:74-79. [DOI: 10.1016/j.clay.2010.04.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
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Affiliation(s)
- T. Krishnaveni
- a Department of Physics , Osmania University , Hyderabad, India
| | - S. Komarneni
- b Materials Research Institute, Pennsylvania State University , University Park, USA
| | - S. R. Murthy
- a Department of Physics , Osmania University , Hyderabad, India
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Meskin PE, Baranchikov AE, Ivanov VK, Kisterev EV, Burukhin AA, Churagulov BR, Oleinikov NN, Komarneni S, Tret'yakov YD. Doklady Chemistry 2003; 389:62-64. [DOI: 10.1023/a:1022978107113] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Affiliation(s)
- S Komarneni
- Department of Agronomy and Materials Research Laboratory, Pennsylvania State University, University Park, Pennsylvania 16802, USA.
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Kloprogge JT, Komarneni S, Yanagisawa K, Fry R, Frost RL. Infrared Emission Spectroscopic Study of the Dehydroxylation via Surface Silanol Groups of Synthetic and Natural Beidellite. J Colloid Interface Sci 1999; 212:562-569. [PMID: 10092388 DOI: 10.1006/jcis.1998.6082] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structural changes of synthetic and natural beidellites during dehydroxylation have been studied using infrared emission spectroscopy of the OH-stretching and bending regions. The OH-stretching region is characterized by two OH-stretching modes around 3600-3615 cm-1 and around 3650 cm-1. These bands strongly decrease in intensity upon dehydroxylation up to 600 degrees C for the natural beidellite and 700-750 degrees C for the synthetic ones. The differences in bandwidth, intensity, and dehydroxylation behavior are interpreted as due to differences in crystallinity with crystallinity increasing in the order natural beidellite < synthetic beidellite BSK3 < synthetic beidellite E498. Above 400 degrees C a new band attributed to silanol groups becomes visible in all samples due to transfer of the hydroxyls from the octahedral layer to the siloxane layer before they are lost. The broad band around 3300-3400 cm-1 is assigned to both H-bonding in H2O and H-bonding to Si-O-Al linkages. The presence of two different OH groups is also reflected in the OH-bending modes around 875-895 cm-1 and 915-925 cm-1 and in the OH-libration modes around 780 and 800-820 cm-1. These bands show a decrease in intensity upon heating and dehydroxylation of the clay structure. Here again the same order can be observed for the disappearance of the bands as for the OH-stretching region. Copyright 1999 Academic Press.
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Affiliation(s)
- JT Kloprogge
- Centre for Instrumental and Developmental Chemistry, Queensland University of Technology, 2 George Street, Brisbane, Q 4001, Australia
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Wlodarczyk P, Komarneni S, Roy R, White WB. Enhanced fluorescence of coumarin laser dye in the restricted geometry of a porous nanocomposite. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/jm9960601967] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Abstract
The microscopic structure of oxygen confined in silica xerogels has been studied as a function of temperature. In large pores, a crystalline solid forms with a structure consistent with that of the bulk. The size of the crystallites is much larger than the pore size, indicating that cooperative effects among pores are important in freezing. As the pore size is decreased, a crossover occurs where solidification results in an amorphous phase in the pores. The resulting amorphous phase is solid but is less ordered than the liquid phase.
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Abstract
Ahydrated, sodium phlogopite mica with a c-axis spacing [d(001)] of 12.23 A made by careful low-temperature leaching, showed extremely high selectivity for cesium. This newly discovered cesium ion sieve is useful in the decontamination as well as immobilization of cesium at room temperature through chemical bonding and may find applications in nuclear waste disposal and in decontamination of the environment after accidental releases of nuclear materials.
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Komarneni S, Suwa Y, Roy R. Enhancing densification of 93% Al2O3-7% MgO triphasic xerogels with crystallineα-Al2O3 and MgAl2O4 seeds. ACTA ACUST UNITED AC 1987. [DOI: 10.1007/bf01739273] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Abstract
Tobermorites have cation-exchange and selectivity properties intermediate between those of clay minerals and zeolites. Aluminum-substituted tobermorites in particular show high selectivity for cesium. This new group of cation exchangers may find applications in catalysis and in nuclear and hazardous waste disposal.
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