scholarly journals Enzymatic synthesis and characterization of polycaprolactone by using immobilized lipase onto a surface-modified renewable carrier

2016 ◽  
Vol 18 (3) ◽  
pp. 134-140 ◽  
Author(s):  
Cansu Ulker ◽  
Nurefsan Gokalp ◽  
Yuksel Guvenilir
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Immobilized Lipase ◽  
Covalent Binding ◽  
Aqueous Media ◽  
Energy Saving Process ◽  
Surface Modified ◽  
First Time ◽  
Polymerization Conditions

Abstract In the present study, rice husk ash, which is a renewable and abundant material, was utilized as a carrier for lipase immobilization for the first time. Poly (ε-caprolactone) synthesis was successfully achieved by the new enzymatic catalyst: Candida antarctica lipase B immobilized onto surface-modified rice husk ashes by covalent binding. It was aimed to obtain optimum polymerization conditions at which highest molecular weight was reached and characterize the polymer produced. Moreover, thermal stability and effectiveness of the new biocatalyst in non-aqueous media were also shown with successful polymerization reactions. In addition, by using the new enzyme preparation, ε-caprolactone was able to be polymerized even at 30°C, which was promising for an energy saving process. Consequently, this work provides a new alternative route for poly (ε-caprolactone) synthesis.

Green Synthesis and Spectroscopic Studies of Ag-rGO Nanocomposites for Highly Selective Mercury (II) Sensing

2018 ◽  
Vol 9 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Shubhangi J. Mane-Gavade ◽  
Sandip R. Sabale ◽  
Xiao-Ying Yu ◽  
Gurunath H. Nikam ◽  
Bhaskar V. Tamhankar
Keyword(s):  
Green Synthesis ◽  
Color Change ◽  
Limit Of Detection ◽  
Aqueous Media ◽  
Suitable Condition ◽  
Cost Effective ◽  
Spectroscopic Studies ◽  
Calibration Plot ◽  
First Time

Introduction: Herein we report the green synthesis and characterization of silverreduced graphene oxide nanocomposites (Ag-rGO) using Acacia nilotica gum for the first time. Experimental: We demonstrate the Hg2+ ions sensing ability of the Ag-rGO nanocomposites form aqueous medium. The developed colorimetric sensor method is simple, fast and selective for the detection of Hg2+ ions in aqueous media in presence of other associated ions. A significant color change was noticed with naked eye upon Hg2+ addition. The color change was not observed for cations including Sr2+, Ni2+, Cd2+, Pb2+, Mg2+, Ca2+, Fe2+, Ba2+ and Mn2+indicating that only Hg2+ shows a strong interaction with Ag-rGO nanocomposites. Under the most suitable condition, the calibration plot (A0-A) against concentration of Hg2+ was linear in the range of 0.1-1.0 ppm with a correlation coefficient (R2) value 0.9998. Results & Conclusion The concentration of Hg2+ was quantitatively determined with the Limit of Detection (LOD) of 0.85 ppm. Also, this method shows excellent selectivity towards Hg2+ over nine other cations tested. Moreover, the method offers a new cost effective, rapid and simple approach for the detection of Hg2+ in water samples.

Synthesis and characterization of red mud and rice husk ash-based geopolymer composites

2013 ◽  
Vol 37 ◽  
pp. 108-118 ◽  
Author(s):  
Jian He ◽  
Yuxin Jie ◽  
Jianhong Zhang ◽  
Yuzhen Yu ◽  
Guoping Zhang
Keyword(s):  
Rice Husk ◽  
Red Mud ◽  
Rice Husk Ash ◽  
Synthesis And Characterization ◽  
Geopolymer Composites

scholarly journals Optimization of nanostructured/nano sized rice husk ash preparation

2020 ◽  
Vol 17 (3(Suppl.)) ◽  
pp. 0953
Author(s):  
Medhat Mostafa ◽  
Hamdy Salah ◽  
Amro B. Saddek ◽  
Nabila Shehata
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Amorphous Silica ◽  
Particle Shape ◽  
Rice Husk Ash ◽  
Loss On Ignition ◽  
Shape Distribution ◽  
Disk Mill ◽  
Grinding Time

The objective of the study is developing a procedure for production and characterization of rice husk ash (RHA). The effects of rice husk (RH) amount, burning/cooling conditions combined with stirring on producing of RHA with amorphous silica, highest SiO2, lowest loss on ignition (LOI), uniform particle shape distribution and nano structured size have been studied. It is concluded that the best amount is 20 g RH in 125 ml evaporating dish Porcelain with burning for 2 h at temperature 700 °C combined with cooling three times during burning to produce RHA with amorphous silica, SiO2 90.78% and LOI 1.73%. On the other hand, cooling and stirring times affect the variation of nano structured size and particle shape distribution. However, no crystalline phases were found in RHA in all cases. Results proved that the Attritor ball mill was more suitable than vibration disk mill for pulverizing nano structured RHA with 50% of particle size (D50) lower than 45 mm and 99 % of particle size (D99) lower than 144 mm to nanosized RHA with D50 lower than 36 nm and D99 lower than 57 nm by grinding time 8.16 min to every 1 g RHA without changes in morphousity of silica.

Elemental Characterization of Rice Husk Ash from Local Rice Species in South Eastern Nigeria

2020 ◽  
Vol 3 (4) ◽  
pp. 1081-1085
Author(s):  
Paul S. Ogbuefi ◽  
Placid Nwaokafor ◽  
Ifeanyi J. Njoku ◽  
Ogechukwu J. Uzuegbunam
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
South Eastern ◽  
Elemental Characterization

scholarly journals Preparation and characterization of rice husk ash (RHA)-TiO2 / ZnO composites and its application in treating effluents from textile industries

2013 ◽  
Vol 47 (4) ◽  
pp. 445-448 ◽  
Author(s):  
MH Kabir ◽  
MF Kabir ◽  
F Nigar ◽  
S Ahmed ◽  
AI Mustafa ◽  
...  
Keyword(s):  
Composite Materials ◽  
Rice Husk ◽  
Rice Husk Ash ◽  
Textile Dye ◽  
X Ray ◽  
Textile Dye Effluent ◽  
Degradation Reaction ◽  
D Values ◽  
Sun Light

Photocatalytic composite materials incorporating the photocatalysts (TiO2, ZnO) with rice husk ash (RHA) have been developed to investigate the photodegradation of real textile dye effluent. The structural characterization of the composite materials was performed using XRD (X-Ray Diffractometer). The characteristic XRD peaks together with the 2? values for both TiO2 and ZnO were in excellent agreement with the standard JCPDS d-values. The efficacy of these composites was examined through the degradation of a textile dye, collected from a local dye house. The sun light was used as the source of illumination for the preceding degradation reaction. Bangladesh J. Sci. Ind. Res. 47(4), 445-448, 2012 DOI: http://dx.doi.org/10.3329/bjsir.v47i4.14075

scholarly journals Improvement of Collapsible Soil Behavior of a Lateritic Soil Using Rice Husk Ash

2015 ◽  
Vol 668 ◽  
pp. 290-296 ◽  
Author(s):  
Luiza P. Fagundes ◽  
Jhaber D. Yacoub ◽  
Andrey C. Lima ◽  
Flávia R. Nakatsuchi ◽  
José A. Lollo ◽  
...  
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Combined Effect ◽  
Building Construction ◽  
Lateritic Soil ◽  
Soil Behavior ◽  
Collapsible Soil ◽  
Lateritic Soils ◽  
Environmental Friendly

Great areas of Brazil present lateritic soils, such as the northeast and the south. Some of these soils have, as main characteristic, instable structures that can present considerable volumetric deformation in the presence of water. This behavior, also named collapse, is responsible for several problems on the building construction such as cracks and fractures that can damage the safety of structures. The aim of this paper is to assess the possibility of improvement of collapsible behavior of a lateritic soil using rice husk ash (RHA). A previous characterization of soil and RHA was performed in order to assess the combined effect of soil/RHA. The results are so promising, showing a new alternative to reduce the collapsible behavior of soils using an environmental friendly technology.

scholarly journals Characterization of rice husk ash prepared by open air burning and furnace calcination

2020 ◽  
Vol 11 (2) ◽  
pp. 24-30
Author(s):  
Mbinda Jonathan Kaleli ◽  
Paul Kuria Kamweru ◽  
Joel Mwangi Gichumbi ◽  
Francis Gichuki Ndiritu
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash

scholarly journals Effects of Sintering Temperature Variation on Synthesis of Glass-Ceramic Phosphor Using Rice Husk Ash as Silica Source

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5413
Author(s):  
Rabiatul Adawiyah Abdul Wahab ◽  
Mohd Hafiz Mohd Zaid ◽  
Sidek Hj. Ab Aziz ◽  
Khamirul Amin Matori ◽  
Yap Wing Fen ◽  
...  
Keyword(s):  
Rice Husk ◽  
Glass Ceramic ◽  
Rice Husk Ash ◽  
Glass Ceramics ◽  
Xrd Analysis ◽  
Sintering Process ◽  
X Ray Diffraction ◽  
Silica Source ◽  
Quenching Method

In this study, the authors attempted to propose the very first study on fabrication and characterization of zinc-boro-silicate (ZBS) glass-ceramics derived from the ternary zinc-boro-silicate (ZnO)0.65(B2O3)0.15(RHA)0.2 glass system through a conventional melt-quenching method by incorporating rice husk ash (RHA) as the silica (SiO2) source, followed by a sintering process. Optimization of sintering condition has densified the sintered samples while embedded beta willemite (β-Zn2SiO4) and alpha willemite (α-Zn2SiO4) were proven in X-ray diffraction (XRD) analysis. Field emission scanning electron microscopy (FESEM) has shown the distribution of willemite crystals in rhombohedral shape crystals and successfully form closely-packed grains due to intense crystallization. The photoluminescence (PL) spectra of all sintered ZBS glasses presented various emission peaks at 425, 463, 487, 531, and 643 nm corresponded to violet, blue, green, and red emission, respectively. The correlation between the densification, phase transformation, microstructure, and photoluminescence of Zn2SiO4 glass-ceramic phosphor is discussed in detail.

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