scholarly journals Physicochemical characterization of biochars from Eucalyptus maiden Entandrophragma cylindricum (Liboyo), Milicia excelsa (Muvula.) and Ocotea michelsonie (licheche) used in Goma city, DR Congo for water treatment potentials

2021 ◽  
Vol 13 (2) ◽  
pp. 15-24
Author(s):  
Amboko Benjamin Muhiwa ◽  
Mathias Fru Fonteh ◽  
Estella Buleng Tamungang Njoyim ◽  
François N. Gapgue

In recent years, research on biochar as an eco-friendly material and cost-effective means for water treatment, soil amendment and carbon sequestration has gained more attention due to the availability of feedstock, the simplicity of the preparation methods, and their enhanced physico-chemical properties. Given that pyrolysis temperature and resident time amongst other factors have significant effect on biochar’s pollutant removal efficacy, this study focused on the evaluation of some properties of biochars produced by pyrolysis (500 - 600 °C) from Entandrophragma cylindricum (ECB), Eucalyptus maiden (EMB), Milicia excelsa (MEB) and Ocotea michelsonie (OMB) sawdusts for their water treatment potentials by using standardized methods. Biomass generated from wood mill in the city of Goma (DR Congo) is valorised for the first time as potential water  purifier. The highest yield was obtained from OMB (36.6%) which was found to be significantly greater that those of ECB and EMB (p<0.05). All the biochars had neutral to weakly alkaline pH (7.10-7.90), very high porosity (92-94%, with EMB having the highest value) and ash content between 9.40 and 18.40%, with the highest value attributed to OMB). Most physical and chemical characteristics of biochars varied significantly due to different wood species. Potential toxic elements were far belowenvironmental threshold values and exchangeable cations were equally detected in the biochars. The obtained biochars are therefore seen as good media for water treatment.

Author(s):  
Suresh Aluvihara ◽  
C.S. Kalpage ◽  
P.W.S.K. Bandaranayake

Activated carbon is a black color solid compound which is fabricated using naturally occurring materials such as woods and species of coal that composed of the majority in carbon. The activated carbon is highly remarkable compound in the catalytic activities in most of chemical industries and water treatment activities because of the significant performances of such activated carbon due to the sufficiency of the surface property which is called as the adsorption with the couple of high porosity. The manufacturing of activated carbon from disposable coconut shells and the investigations of the physic-chemical characteristics of such activated carbon were the expectances of the existing research. Domestically collected coconut shells were burnt in the range of different temperatures 390°C–300°C after removing unnecessary constituents. The chemical composition of the powdered activated carbon was inspected using an X-ray fluorescence (XRF) spectrophotometer and the surfaces of prepared activated carbon were examined using an optical microscope. As the outcomes of the above experiments, it seems that the most adequate burning temperature for the manufacturing of that batch of coconut shells was in the range of 330°C–350°C, 68.85% of ferrous and 31.15% of potassium as the composed metallic element apart from the non metallic carbon and the pure black color non- composite surfaces were observed under the microscopic studies. It is encouraged to develop this production using cost effective materials such as the shells of fesults which are belonging to the palm cast while utilizing the productions through the various applications in chemical industries


2019 ◽  
Vol 9 (3) ◽  
pp. 232-248 ◽  
Author(s):  
I. Tlili ◽  
Tawfeeq Abdullah Alkanhal

Abstract The need for beneficial innovations in filtration expertise has lead to little consideration of cutting-edge materials, such as nanofiber membranes for water distillation. The presence of organic matter and traces of organics accumulation in wastewater poses a major problem and current technologies such as coagulation/flocculation and chlorine technology are unable to yield satisfying results. The extra volume of sludge generated by these technologies needs further processing and disposal. Nanotechnology has outstanding potential for filtration applications due to its capability to create precise structural controlled materials for such requirements. Electrospun nanofibrous membranes (ENMs) are cutting edge membrane technology that offer substantial high flux and high rejection rates compared to conventional membranes. ENMs present a revolution in water and sewage purification by offering a lightweight, cost-effective, and lower energy consumption process compared with conventional membranes. ENMs possess high porosity, generally approximately 80%, while conventional membranes have 5–35% porosity. Nano-engineered membranes have great potential in water treatment due to their exotic properties. In this connection, electrospinning membranes are emerging as a versatile technique with promising features for water treatment. This work highlights the application of ENM in wastewater treatment and surface modification of nanomembranes in order to address fouling issues and wastewater treatment from Tabuk Sewage Treatment Plant, Saudi Arabia.


2011 ◽  
Vol 39 (3) ◽  
pp. 193-209 ◽  
Author(s):  
H. Surendranath ◽  
M. Dunbar

Abstract Over the last few decades, finite element analysis has become an integral part of the overall tire design process. Engineers need to perform a number of different simulations to evaluate new designs and study the effect of proposed design changes. However, tires pose formidable simulation challenges due to the presence of highly nonlinear rubber compounds, embedded reinforcements, complex tread geometries, rolling contact, and large deformations. Accurate simulation requires careful consideration of these factors, resulting in the extensive turnaround time, often times prolonging the design cycle. Therefore, it is extremely critical to explore means to reduce the turnaround time while producing reliable results. Compute clusters have recently become a cost effective means to perform high performance computing (HPC). Distributed memory parallel solvers designed to take advantage of compute clusters have become increasingly popular. In this paper, we examine the use of HPC for various tire simulations and demonstrate how it can significantly reduce simulation turnaround time. Abaqus/Standard is used for routine tire simulations like footprint and steady state rolling. Abaqus/Explicit is used for transient rolling and hydroplaning simulations. The run times and scaling data corresponding to models of various sizes and complexity are presented.


2018 ◽  
Author(s):  
Ravi Shankar ◽  
Sofia Marchesini ◽  
Camille Petit

Porous boron nitride is gaining significant attention for applications in molecular separations, photocatalysis, and drug delivery. All these areas call for a high degree of stability (or a controlled stability) over a range of chemical environments, and particularly under humid conditions. The hydrolytic stability of the various forms of boron nitride, including porous boron nitride, has been sparingly addressed in the literature. Here, we map the physical-chemical properties of the material to its hydrolytic stability for a range of conditions. Using analytical, imaging and spectroscopic techniques, we identify the links between the hydrolytic instability of porous boron nitride and its limited crystallinity, high porosity as well as the presence of oxygen atoms. To address this instability issue, we demonstrate that subjecting the material to a thermal treatment leads to the formation of crystalline domains of h-BN exhibiting a hydrophobic character. The heat-treated sample exhibits enhanced hydrolytic stability, while maintaining a high porosity. This work provides an effective and simple approach to producing stable porous boron nitride structures, and will progress the implementation of the material in applications involving interfacial phenomena.<br>


Author(s):  
Tochukwu Moses ◽  
David Heesom ◽  
David Oloke ◽  
Martin Crouch

The UK Construction Industry through its Government Construction Strategy has recently been mandated to implement Level 2 Building Information Modelling (BIM) on public sector projects. This move, along with other initiatives is key to driving a requirement for 25% cost reduction (establishing the most cost-effective means) on. Other key deliverables within the strategy include reduction in overall project time, early contractor involvement, improved sustainability and enhanced product quality. Collaboration and integrated project delivery is central to the level 2 implementation strategy yet the key protocols or standards relative to cost within BIM processes is not well defined. As offsite construction becomes more prolific within the UK construction sector, this construction approach coupled with BIM, particularly 5D automated quantification process, and early contractor involvement provides significant opportunities for the sector to meet government targets. Early contractor involvement is supported by both the industry and the successive Governments as a credible means to avoid and manage project risks, encourage innovation and value add, making cost and project time predictable, and improving outcomes. The contractor is seen as an expert in construction and could be counter intuitive to exclude such valuable expertise from the pre-construction phase especially with the BIM intent of äóÖbuild it twiceäó», once virtually and once physically. In particular when offsite construction is used, the contractoräó»s construction expertise should be leveraged for the virtual build in BIM-designed projects to ensure a fully streamlined process. Building in a layer of automated costing through 5D BIM will bring about a more robust method of quantification and can help to deliver the 25% reduction in overall cost of a project. Using a literature review and a case study, this paper will look into the benefits of Early Contractor Involvement (ECI) and the impact of 5D BIM on the offsite construction process.


2002 ◽  
Vol 2 (1) ◽  
pp. 233-240 ◽  
Author(s):  
J. Cromphout ◽  
W. Rougge

In Harelbeke a Water Treatment Plant with a capacity of 15,000 m3/day, using Schelde river water has been in operation since April 1995. The treatment process comprises nitrification, dephosphatation by direct filtration, storage into a reservoir, direct filtration, granular activated carbon filtration and disinfection. The design of the three-layer direct filters was based on pilot experiments. The performance of the plant during the five years of operation is discussed. It was found that the removal of atrazin by activated carbon depends on the water temperature.


2021 ◽  
Author(s):  
Luke D Geoffrion ◽  
David Medina Cruz ◽  
Matthew Kusper ◽  
Sakr Elsaidi ◽  
Fumiya Watanabe ◽  
...  

Bismuth oxide is an important bismuth compound having applications in electronics, photo-catalysis and medicine. At the nanoscale, bismuth oxide experiences a variety of new physico-chemical properties because of its increased...


Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 885
Author(s):  
Nicole Knoblauch ◽  
Peter Mechnich

Zirconium-Yttrium-co-doped ceria (Ce0.85Zr0.13Y0.02O1.99) compacts consisting of fibers with diameters in the range of 8–10 µm have been successfully prepared by direct infiltration of commercial YSZ fibers with a cerium oxide matrix and subsequent sintering. The resulting chemically homogeneous fiber-compacts are sinter-resistant up to 1923 K and retain a high porosity of around 58 vol% and a permeability of 1.6–3.3 × 10−10 m² at a pressure gradient of 100–500 kPa. The fiber-compacts show a high potential for the application in thermochemical redox cycling due its fast redox kinetics. The first evaluation of redox kinetics shows that the relaxation time of oxidation is five times faster than that of dense samples of the same composition. The improved gas exchange due to the high porosity also allows higher reduction rates, which enable higher hydrogen yields in thermochemical water-splitting redox cycles. The presented cost-effective fiber-compact preparation method is considered very promising for manufacturing large-scale functional components for solar-thermal high-temperature reactors.


Vaccines ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 390
Author(s):  
Frank Kowalzik ◽  
Daniel Schreiner ◽  
Christian Jensen ◽  
Daniel Teschner ◽  
Stephan Gehring ◽  
...  

Increases in the world’s population and population density promote the spread of emerging pathogens. Vaccines are the most cost-effective means of preventing this spread. Traditional methods used to identify and produce new vaccines are not adequate, in most instances, to ensure global protection. New technologies are urgently needed to expedite large scale vaccine development. mRNA-based vaccines promise to meet this need. mRNA-based vaccines exhibit a number of potential advantages relative to conventional vaccines, namely they (1) involve neither infectious elements nor a risk of stable integration into the host cell genome; (2) generate humoral and cell-mediated immunity; (3) are well-tolerated by healthy individuals; and (4) are less expensive and produced more rapidly by processes that are readily standardized and scaled-up, improving responsiveness to large emerging outbreaks. Multiple mRNA vaccine platforms have demonstrated efficacy in preventing infectious diseases and treating several types of cancers in humans as well as animal models. This review describes the factors that contribute to maximizing the production of effective mRNA vaccine transcripts and delivery systems, and the clinical applications are discussed in detail.


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