One-pot synthesis of NaA and NaP zeolite powders using agro-waste material and other low cost organic-free precursors

NaA and NaP zeolite powders were synthesized by hydrothermal condition at 100 degrees C/15-96 h using agro-waste material, rice husk ash as silica source in the presence of other organic-free low cost precursors like aluminum foil, sodium hydroxide and water. The powders were characterized by thermogravimetric analysis (TGA), differential thermal analysis (DTA), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, N-2 physisorption studies, and field emission scanning electron microscopy (FESEM). The BET surface area values of NaA and NaP powders were in the range of 348-179 m(2) g(-1) and 129-85 m(2) g(-1), respectively. FESEM images showed flower-like morphology for the NaA powders obtained at 100 degrees C/15 h, and broken cashew-nut-like morphology for the NaP powders synthesized at 100 degrees C/72 h. (C) 2013 Elsevier Ltd and Techna Group S.r.l. All rights reserved

Synthesis of cashew nut-like zeolite NaP powders using agro-waste material as silica source

Cashew nut-like zeolite NaP powders were synthesized using agro-waste material, rice husk ash as silica source via its in-situ extraction in the presence of other organic-free low cost precursors like aluminum foil, sodium hydroxide and water under hydrothermal condition at 100 degrees C for 48 h. The powders were characterized by thermogravimetry analysis (TGA), differential thermal analysis (DTA), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, N-2 physisorption measurements and field emission scanning electron microscopy (FESEM). BET surface area and total pore volume of the powders were 129 m(2) g(-1) and 0.18 cm(3) g(-1), respectively. FESEM images showed cashew nut-like morphology of the powders, and Si/Al ratio of the powders was found to be 2.01 as indicated by the elemental analysis with energy dispersive X-ray (EDX). (C) 2013 Elsevier B.V. All rights reserved

Synthesis of zeolite T powders by direct dissolution of rice husk ash: an agro-waste material

Rice husk ash (RHA), an agro-waste material, was used for the synthesis of zeolite T powders following a simple and cost-effective process. In this process, silica as silicate was directly extracted from solid RHA particles in the presence of aluminate and other aqueous-based precursor materials. The synthesized powders were characterized by thermogravimetry analysis, differential thermal analysis, X-ray diffraction, Fourier transform infrared spectroscopy, N-2 physisorption measurements, and field emission scanning electron microscopy (FESEM). Crystallization of zeolite T powders was noticed at 100 A degrees C/24 h. The vibration bands of the powders at around 580 and 630 cm(-1) indicated the characteristic double six ring of zeolite T. Micropore surface area and micropore volume of zeolite T increased significantly at 100 A degrees C/72 h. FESEM images showed ellipse-shaped morphology of the powders, and their aspect ratio increased with increase in reaction time. A tentative mechanism was proposed for direct extraction of silica as silicate from RHA, and its conversion to zeolite T in the presence of other aqueous-based precursors by a single step process

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Not AvailableRice is the most important food crop worldwide and sustainable rice production is important for ensuring global food security. Biotic stresses limit rice production significantly and among them, bacterial blight (BB) disease caused by Xanthomonas oryzae pv. oryzae (Xoo) is very important. BB reduces rice yields severely in the highly productive irrigated and rainfed lowland ecosystems and in recent years; the disease is spreading fast to other rice growing ecosystems as well. Being a vascular pathogen, Xoo interferes with a range of physiological and biochemical exchange processes in rice. The response of rice to Xoo involves specific interactions between resistance (R) genes of rice and avirulence (Avr) genes of Xoo, covering most of the resistance genes except the recessive ones. The genetic basis of resistance to BB in rice has been studied intensively, and at least 44 genes conferring resistance to BB have been identified, and many resistant rice cultivars and hybrids have been developed and released worldwide. However, the existence and emergence of new virulent isolates of Xoo in the realm of a rapidly changing climate necessitates identification of novel broad-spectrum resistance genes and intensification of gene-deployment strategies. This review discusses about the origin and occurrence of BB in rice, interactions between Xoo and rice, the important roles of resistance genes in plant’s defense response, the contribution of rice resistance genes toward development of disease resistance varieties, identification and characterization of novel, and broad-spectrum BB resistance genes from wild species of Oryza and also presents a perspective on potential strategies to achieve the goal of sustainable disease management.Not Availabl