Quantitative geochemical modelling using leaching tests: application for coal ashes produced by two South African thermal processes

The present work focuses on the reactivity of coal fly ash in aqueous solutions studied through geochemical modelling. The studied coal fly ashes originate from South African industrial sites. The adopted methodology is based on mineralogical analysis, laboratory leaching tests and geochemical modelling. A quantitative modelling approach is developed here in order to determine the quantities of different solid phases composing the coal fly ash. It employs a geochemical code (PHREEQC) and a numerical optimisation tool developed under MATLAB, by the intermediate of a coupling program. The experimental conditions are those of the laboratory leaching test, i.e. liquid/solid ratio of 10 L/kg and 48 h contact time. The simulation results compared with the experimental data demonstrate the feasibility of such approach, which is the scope of the present work. The perspective of the quantitative geochemical modelling is the waste reactivity prediction in different leaching conditions and time frames. This work is part of a largest research project initiated by Sasol and Eskom companies, the largest South African coal consumers, aiming to address the issue of waste management of coal combustion residues and the environmental impact assessment of coal ash disposal on land.     

Experimental investigation on improvement of storage stability of bio-oil derived from intermediate pyrolysis of Calophyllum inophyllum seed cake

Due to the unstable nature of bio-oil, it becomes mandatory to analyze the changes in physical and chemical properties of the bio-oil during storage to appreciate its chemical instability, for developing stabilization strategies. The present study aims to investigate the oxidative and thermal stability of bio-oil extracted from pyrolyzing Calophyllum inophyllum (CI) deoiled seed cake in a fixed bed reactor at 500 °C under the constant heating rate of 30 °C/min. Each stability analysis method involve an accelerated aging procedure based on standards established by ASTM (D5304 and E2009) and European standard (EN 14112). Fourier Transform Infrared Spectroscopy and Gas Chromatography-Mass Spectrometry were employed to analytically characterize the un-aged and aged bio-oil samples. The results clearly depict that stabilizing Calophyllum inophyllum bio-oil with 10% (w/w) methanol improved its stability than that of the crude sample. Addition of methanol reduced the change in viscosity of bio-oil by 38.55% during accelerated aging process. The oxidation stability index of bio-oil stabilized with methanol was found to be 3.97 h which is in accordance with ASTM D6751. FT-IR and GC-MS results showed an increase in the relative concentration of C-O (carboxylic acids, ethers and esters) and C=O (carbonyl) functional groups in aged bio-oil samples.     

Green technology and performance consequences of an eco-friendly substance on a 4-stroke diesel engine at standard injection timing and compression ratio

Journal of Mechanical Science and Technology - This study experimentally focuses on finding the optimum blend ratio for Direct injection (D.I) diesel engine fuelled with mahua oildiesel and...     

The use of slow releasing nanoparticle encapsulated Azadirachtin formulations for the management of Caryedon serratus O. (groundnut bruchid)

Nanobiotechnology is one of the emerging fields and its interventions in agriculture is been attracting the scientific community. Herein, the authors first to report on control of groundnut bruchid (Caryedon serratus O.) using nanoscale zinc oxide (ZnONPs) particles and nanoscale chitosan (CNPs) particles‐based Azadirachtin formulations. ZnONPs and CNPs were prepared using sol–gel and ion tropic gelation techniques, respectively. Neem seed kernel extract (NSKE) 5% and Neem oil (3000 and 1000 ppm) were encapsulated using the prepared nanoscale materials and characterised using the techniques such as dynamic light scattering, high‐resolution transmission electron microscopy. Spherical‐shaped nanoparticles were formed after encapsulation with the required bio‐materials (ZnONPs 33.1 nm; CNPs 78.8 nm; neem oil encapsulated (3000 ppm) ZnONPs 182.9 nm; NSKE encapsulated ZnONPs 84.9 nm) and observed that the particles are stable (52.3 mV for ZnONPs, −36.2 mV for CNPs, −43.0 mV for neem oil encapsulated (3000 ppm) ZnONPs and −39.4 mV for NSKE encapsulated ZnONPs). NSKE encapsulated CNPs were able to contain groundnut bruchid up to 180 days with 54.61% weight loss compared to other formulations tested. Thus biomaterial encapsulated nanoscale material formulations are proved to be effective in controlling stored grain pests to reduce huge economic losses.Inspec keywords: nanobiotechnology, agricultural products, toxicology, agrochemicals, food safety, sol‐gel processing, food preservation, agriculture, II‐VI semiconductors, storage, nanoparticles, transmission electron microscopy, encapsulation, nanofabrication, zinc compounds, wide band gap semiconductors, food processing industry, light scattering, materials preparation, pest control, nanocompositesOther keywords: voltage ‐36.2 mV, voltage ‐43.0 mV, voltage ‐39.4 mV, voltage 52.3 mV, size 84.9 nm, size 182.9 nm, size 78.8 nm, size 33.1 nm, NSKE, neem seed kernel extract, caryedon serratus O., CNPs, bio‐materials, nanoscale materials, nanoparticle, encapsulation, spherical‐shaped nanoparticles, high‐resolution transmission electron microscopy, neem oil, ion tropic gelation techniques, sol–gel, nanoscale chitosan particles, nanoscale zinc oxide particles, scientific community, groundnut bruchid, Azadirachtin formulations, biomaterial encapsulated nanoscale material formulations     

ASSAY OF MALT β-GLUCANASE USING AZO-BARLEY GLUCAN: AN IMPROVED PRECIPITANT

A procedure recently described for the assay of malt β-glucanase, which employs a dye-labelled and chemically-modified barley β-glucan substrate, has been improved by changing the precipitant solution used to terminate the reaction. The new precipitant solution contains 0·4% (w/v) zinc acetate and 4% (w/v) sodium acetate dissolved in 80% (v/v) aqueous methyl cellosolve. With this precipitant the procedure can be directly applied to the assay of cellulase activity, and with minor modification, to the assay of lichenase activity.