scholarly journals Extraction and Characterization of Biogenic Silica Obtained from Selected Agro-Waste in Africa

2021 ◽  
Vol 11 (21) ◽  
pp. 10363
Author(s):  
Clement Owusu Prempeh ◽  
Steffi Formann ◽  
Thomas Schliermann ◽  
Hossein Beidaghy Dizaji ◽  
Michael Nelles
Keyword(s):  
Citric Acid ◽  
Biogenic Silica ◽  
Food Production ◽  
Value Added ◽  
Emission Spectrometry ◽  
Biomass Fuels ◽  
X Ray ◽  
Biomass Residues ◽  
Pre Treatment

Increased amounts of available biomass residues from agricultural food production are present widely around the globe. These biomass residues can find essential applications as bioenergy feedstock and precursors to produce value-added materials. This study assessed the production of biogenic silica (SiO2) from different biomass residues in Africa, including cornhusk, corncob, yam peelings, cassava peelings and coconut husks. Two processes were performed to synthesize the biogenic silica. First, the biomass fuels were chemically pre-treated with 1 and 5% w/v citric acid solutions. In the second stage, combustion at 600 °C for 2 h in a muffle oven was applied. The characterization of the untreated biomasses was conducted using Inductively coupled plasma—optical emission spectrometry (ICP-OES), thermal analysis (TG-DTA) and Fourier-transform infrared spectroscopy (FTIR). The resulting ashes from the combustion step were subjected to ICP, nitrogen physisorption, Energy dispersive X-ray spectroscopy (EDX) as well as X-Ray diffraction (XRD). ICP results revealed that the SiO2 content in the ashes varies between 42.2 to 81.5 wt.% db and 53.4 to 90.8 wt.% db after acidic pre-treatment with 1 and 5 w/v% acid, respectively. The relative reductions of K2O by the citric acid in yam peel was the lowest (79 wt.% db) in comparison to 92, 97, 98 and 97 wt.% db calculated for corncob, cassava peel, coconut husk and cornhusk, respectively. XRD analysis revealed dominant crystalline phases of arcanite (K2SO4), sylvite (KCl) and calcite (CaCO3) in ashes of the biomass fuels pre-treated with 1 w/v% citric acid due to potassium and calcium ions present. In comparison, the 5 w/v% citric acid pre-treatment produced amorphous, biogenic silica with specific surface areas of up to 91 m2/g and pore volumes up to 0.21 cm3/g. The examined biomass residues are common wastes from food production in Africa without competition in usage with focus application. Our studies have highlighted a significant end-value to these wastes by the extraction of high quality, amorphous silica, which can be considered in applications such as catalyst support, construction material, concrete and backing material.

Preparation of LiFePO4/C Composite Powders

2011 ◽  
Vol 391-392 ◽  
pp. 377-380
Author(s):  
Guo Jun Li ◽  
Ming Yang ◽  
Hai Li Jing ◽  
Rui Ming Ren
Keyword(s):  
Citric Acid ◽  
Oxalic Acid ◽  
Specific Capacity ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Composite Powders ◽  
Charge Capacity ◽  
X Ray ◽  
Initial Charge

LiFePO4/C composite powders were prepared by a simple reaction of as-synthesized FePO4•2H2O, LiOH•H2O, oxalic acid and citric acid. The influence of oxalic acid and citric acid in different ratios was investigated on morphology and electrochemical performance of LiFePO4/C composite powders. The characterization of the composites included X-ray diffraction (XRD) and scanning electron microscopy (SEM). The XRD analysis indicates that the material is well crystallized without impurities. The obtained LiFePO4/C composite powders with well dispersion at CA/OA ratio of 1:1.50 and the initial charge capacity reached 159.3 mAhg-1 at 0.1C rate, meanwhile, the particles prepared at 1:0.75 were close to spherical in shape and the specific capacity value was 149.8 mAhg-1 at 0.1C rate, with a slight decrease on greater C-rates reaching 141.3 mAhg-1 at 1C.

Characterization of Mycelium-Like Material Formed During Drying of Salt Stock Prunes

1994 ◽  
Vol 57 (9) ◽  
pp. 817-819
Author(s):  
ROBIN Y.-Y. CHIOU ◽  
WEN-CHING TZENG ◽  
KUO-FONG HUANG
Keyword(s):  
Organic Matter ◽  
Sodium Chloride ◽  
Citric Acid ◽  
Diffraction Analysis ◽  
Diffraction Pattern ◽  
X Ray Diffraction ◽  
X Ray

Material with the appearance of mold mycelium was formed on salt stock prunes during drying. The moisture-free mycelium-like material consisted of 98.5 to 98.7% sodium chloride (NaCl), 1.67% organic matter and 0.165% acidity expressed as citric acid. X-ray diffraction analysis of the material revealed a diffraction pattern similar to that of NaCl. Formation of the material was dependent upon the efficiency and extent of drying. However, the material was not observed on deskinned salt stock prunes subjected to drying.

scholarly journals Green Synthesis and Characterization of Biosilica Produced from Sugarcane Waste Ash

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Rodrigo Heleno Alves ◽  
Thais Vitória da Silva Reis ◽  
Suzimara Rovani ◽  
Denise Alves Fungaro
Keyword(s):  
Silica Particle ◽  
Value Added ◽  
Acid Precipitation ◽  
Gel Formation ◽  
X Ray ◽  
A Value ◽  
Adsorption Analysis ◽  
Amorphous Nature ◽  
Chemical Techniques

In this study, ash from sugarcane waste was used in the synthesis of biosilica using alkaline extraction followed by acid precipitation. Different parameters that could influence the silica particle synthesis were evaluated. The ash and synthesized biosilica were characterized by a combination of spectroscopic and chemical techniques such as XRD, XRF, SEM, particle size analyser, N2 adsorption analysis, TGA, and FTIR. The best condition for biosilica production was achieved with fusion method and aging temperature of 80°C for 1 h during gel formation. X-ray powder diffraction pattern confirms the amorphous nature of synthesized silica. The purity of the prepared silica was 99% silica which was confirmed by means of XRF. The experimental data suggest that the sugarcane waste ash could be converted into a value-added product, minimizing the environmental impact of disposal problems.

Preparation and Characterization of Citric Acid Modified Marigold Dregs Biosorbents

2011 ◽  
Vol 236-238 ◽  
pp. 895-898
Author(s):  
Yi Wang ◽  
Ting Zhang ◽  
Kun Jie Wang ◽  
De Yi Zhang
Keyword(s):  
Citric Acid ◽  
Photoelectron Spectroscopy ◽  
Low Cost ◽  
Infrared Emission ◽  
Hydroxyl Groups ◽  
High Adsorption ◽  
Adsorption Ability ◽  
X Ray ◽  
Adsorption Quantity

The objectives of this study were to convert marigold dregs to a cationic metal ions and dye adsorbent and further to investigate the potential of using the adsorbent for the removal of copper(Ⅱ) and methylene blue (MB) from effluents. The base washed marigold dregs and citric acid (CA) modified marigold dregs (MMD) were prepared and the structure were investigated by fourier transform infrared, emission scanning electron microscope and X-ray photoelectron spectroscopy. The results show that the modification did not significantly change the morphology of the dregs surface structure but the esterificated reaction could increase the carboxyl groups and hydroxyl groups on the surface of the adsorbent. The adsorption ability are also evaluated by MB and copper(Ⅱ) and the results show the MMD is an excellent adsorbent. Due to the high adsorption quantity, it may be used as a low cost alternate adsorbent for the elimination of metal and dye ions form effluents.

Material and Interface Characterization of Cu99Ti1 Thin Films Metallized on Polyimide

1997 ◽  
Vol 476 ◽  
Author(s):  
E. Kondoh ◽  
T.P. Nguyen
Keyword(s):  
Photoelectron Spectroscopy ◽  
Analysis Data ◽  
Alloy Element ◽  
Composition Analysis ◽  
Copper Films ◽  
X Ray ◽  
Interface Characterization ◽  
Drastic Increase ◽  
Pre Treatment

AbstractCopper films with a small amount of an alloy element (1 wt % Ti) were metallized on polyimide. Plasma pre-treatment of the polyimide surface and post-metallization annealing were used to modify the interface. Interfaces and metal film layers were investigated; a drastic increase in adhesion strength, the suppression of Cu diffusion into polyimide, and the improvement of (111) texture were found. Composition analysis data taken from the interface indicated the accretion of nitrogen at the interface. The formation of Ti-related chemical bonds, suggested by X-ray photoelectron spectroscopy, can explain the above-mentioned experimental results.

scholarly journals The Production of Biogenic Silica from Different South African Agricultural Residues through a Thermo-Chemical Treatment Method

2021 ◽  
Vol 13 (2) ◽  
pp. 577
Author(s):  
Ncamisile Nondumiso Maseko ◽  
Denise Schneider ◽  
Susan Wassersleben ◽  
Dirk Enke ◽  
Samuel Ayodele Iwarere ◽  
...  
Keyword(s):  
Citric Acid ◽  
South African ◽  
Elemental Analysis ◽  
Chemical Treatment ◽  
Biogenic Silica ◽  
Textural Properties ◽  
Treatment Method ◽  
Attractive Alternative ◽  
Average Pore ◽  
X Ray

A thermo-chemical treatment method was used to produce biogenic amorphous silica from South African sugarcane and maize residues. Different fractions of South African sugarcane (leaves, pith, and fiber) were processed for silica production. The biomass samples were leached with either 7 wt% citric acid or 7 wt% sulfuric acid at 353 K for 2 h prior to being rinsed, dried and combusted using a four-step program ranging from room temperature to 873 K in a furnace. The characterization of the pre-treated biomass samples was conducted using thermogravimetric analysis (TG/DTA), X-ray fluorescence analysis (XRF) and elemental analysis (CHN), while the final products were characterized by XRF, X-ray diffraction (XRD), elemental analysis, nitrogen physisorption and scanning electron microscopy (SEM). Citric acid pre-treatment proved to be an attractive alternative to mineral acids. Amorphous biogenic silica was produced from sugarcane leaves in good quality (0.1 wt% residual carbon and up to 99.3 wt% silica content). The produced biogenic silica also had great textural properties such as a surface area of up to 323 m2 g−1, average pore diameter of 5.0 nm, and a pore volume of 0.41 cm3 g−1.

scholarly journals Classification of spent Li-ion batteries based on ICP-OES/X-ray characterization of the cathode materials

2020 ◽  
Vol 74 (3) ◽  
pp. 221-230
Author(s):  
Dragana Medic ◽  
Snezana Milic ◽  
Sladjana Alagic ◽  
Ivan Djordjevic ◽  
Silvana Dimitrijevic
Keyword(s):  
Chemical Composition ◽  
Cathode Material ◽  
Cathode Materials ◽  
Inductively Coupled Plasma ◽  
Lithium Ion ◽  
Rapid Expansion ◽  
Emission Spectrometry ◽  
X Ray ◽  
Spent Libs

Development of lithium-ion batteries (LIBs) during the latest decades resulted in improved performances of the new integrated cathode materials and in their wide applications. This rapid expansion of new materials led to the intensive replacement of the old-fashioned, traditional materials and increased a simultaneous accumulation of both kinds of materials at extremely hazardous electronic waste sites, which additionally increased an urgent need for their recycling. Most importantly, in this way, spent LIBs may further serve as a significant source of valuable metals such as Li and cobalt. However, one of the key problems in LIBs recycling is the absence of a precise battery classification/sorting based on the chemical composition of the used cathode material. In this paper, characterization of the cathode material was performed regarding chemical composition of 40 samples of spent LIBs using inductively coupled plasma - optical emission spectrometry and X-ray diffraction. Preparation of the samples, (pretreatment) included: discharging, dismantling, separation of the main components (cathode, anode and the separator), and detachment of the cathode material from the aluminium foil. The obtained results showed that, in the investigated commercially available LIBs, lithium cobalt oxide was the most frequently used (cathode) material.

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