Pumice is a porous volcanic rock containing a significant proportion of silica and alumina, and which has a low iron content. This natural, silica-rich material attracts wide attention because of its applications in adsorption processes, heterogeneous catalysis and nanotechnology. In this contribution, the white amorphous silica nanoparticles were extracted using an optimized alkaline treatment and an acid-precipitation process using grey pumice powder. The isolated amorphous silica SiO2 was characterized via X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FTIR), Transmission Electronic Microscopy (TEM-EDS), N2 adsorption/desorption measurements and simultaneous Thermal Gravimetry/Differential Thermal Analysis (TG/DTA). The obtained results indicated that the nanosilica powder was successfully prepared via the acid-base route with a predominantly amorphous mesoporous structure having a high surface area (422m2/g). The TEM images exhibited relatively homogeneous dispersed nanosilica parti...

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The Synthesis and Characterization of Low-Cost Mesoporous Silica SiO2 from Local Pumice Rock

This review addresses the structure, properties, applications and future scope of lemongrass, which constitutes an abundant source of plant material around the world. As a source of cellulose, it has been successfully used for the adsorption of metal ions and dyes and for manufacturing paper and pulp. Recently, it has shown promise in the production of composites and bio energy, as well as obtaining silica and other metal oxides. However, previous research studies have mostly concentrated on utilizing the biological activities of the constituents in therapeutic uses, food preservation, cosmetics and agriculture. Therefore, this review covers literature on all areas of current studies on lemongrass and identifies its multidimensional potential. Furthermore, this review describes the intended application of lemongrass as a source of cellulosic matter, more specifically in the materials science field.

Lemongrass ( Cymbopogon) : a review on its structure, properties, applications and recent developments

Ultra-high surface area nano-porous silica from expanded perlite: Formation and characterization

Production of Activated Carbon and Precipitated White Nanosilica from Rice Husk Ash

Lemon grass is an inexpensive raw material that can be used to produce natural silica. A method using hydrochloric acid (HCl) leaching followed by thermal combustion at 600 °C was developed to produce purified silica from lemon grass. Acid leaching temperatures of 33, 50, 80, and 110 °C were used. The silica content of the lemon grass ash was characterized using X-ray fluorescence (XRF), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared (FTIR) analysis. The shape and texture of the lemon grass ash were studied using SEM. The highest silica content (98.59%) was produced by lemon grass that had been treated at the highest leaching temperature (110 °C). Other elements that were found in the lemon grass ash were magnesium, calcium, potassium, and chlorine. XRD analysis showed that the crystallinity of the silica in treated lemon grass ash increased with increasing leaching temperature. The FTIR analysis confirmed the presence of siloxane and silanol bonds in lemon grass that was calcined at different leaching temperatures.

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A Simple Method for the Production of Pure Crystalline Silica from Lemon Grass

A simple method based on alkaline extraction followed by acid precipitation and acid dissolution has been developed to produce pure amorphous silica from perlite. The reaction parameters such as molar ratio of NaOH/SiO2, reaction time and reaction temperature are varied for obtaining maximum silica conversion. About 70.6 % pure precipitated silica from perlite has been achieved in closed system at 120 oC within 60 min. XRF, BET surface area, XRD, FTIR and SEM techniques are used to characterize the physico-chemical attributes of materials. The present research includes a cost benefit process under optimized conditions for produce wealth out of waste

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Pure Silica Extraction from Perlite: ItsCharacterization and Affecting factors

The objective of this study was to develop a method to produce amorphous silica from perlite under microwave irradiation and to determine the influence of different NaOH concentration, microwave irradiation time and temperature on the percentage yield of SiO2 content in the obtained amorphous silica. The whole process was divided into three steps:– (i) alkali solubilisation of perlite (ii) subsequent gel formation and (iii) acid dissolution. The synthesized materials were characterized by XRF, BET surface area, XRD, FTIR and SEM-EDS techniques. The maximum percentage yield of SiO2 (94.48%) content was extracted by 4 N NaOH at 90 °C for 15 min. The specific surface area of synthesized AS was found to be ~104 m 2 /g. EDS analysis indicated that silicon was the most abundant element present in AS. The XRD pattern and FTIR data supported the increment in amorphous nature and hydrogen bonded silanol and siloxane groups in AS respectively as compared with raw perlite. The results show that this novel preparation procedure provides an easy pathway to produce amorphous silica with high SiO2 content from perlite, solid waste, according to specification.

Niharika Shringi

Papers

Pure Silica Extraction from Perlite: ItsCharacterization and Affecting factors

A Facile Method for Production of Amorphous Silica from Perlite under Microwave Irradiation

SO_4^2−/SnO_2-Fly Ash as Bifunctional Catalyst for Microwave-Assisted Single-Step Condensation of 2-Naphthol and Aromatic Aldehydes