A Morphological Characterization of High Yield Chitin from Periwinkle Shells

Research on obtaining chitin from periwinkle shell is scarce due to the very low yield of chitin from this kind of shell. Thisstudy reports a method of processing periwinkle shells to obtain high yield, bio-medically suitable chitin. The experimentwas designed using IM and 2M concentrations of HCl for demineralization and a 1M NaOH concentration for deproteinization. FTIR, SEM, XRD and DTA analytical tools were used to characterize the extracted chitin. The FTIR spectral, XRD patterns and SEM analysis, revealed the complete removal of calcium carbonate by the acid concentrations used. The particle-like form of periwinkle shell was transformed to sheet-like fiber and globular-like fiber of α-chitin by increasing the concentration of HCl from1M to 2M respectively. The crystal size increased from 11.2Å (1M HCl) to 13.4Å (2M HCl). The yield of chitin from periwinkle shell also increased from 52% to 71% using 1M and 2M HCl respectively. Thus, acid concentrations can be used to alter the structure of chitin with different mechanical properties

A Simulation and Experimental Investigation of the Thermal Characteristics of Refractory Bricks Produced Using Fireclay and Agroforestry Wastes

Manufacturing and processing industries usually consume large quantities of materials and energy in the course of their operations. The energy supplied for high-temperature processes are used partially for the actual technical process and between 30 to 40% of the energy escapes through the walls of the reactor into the atmosphere, leading to a high degree of thermal inefficiency and fuel consumption. This paper studies the thermal behaviour of insulating refractory bricks produced from a blend of fireclay and agroforestry wastes. The fireclays used were obtained from Ukpor deposit in Anambra State (Latitude 5.95°N, Longitude 6.92°E), Osiele deposit in Abeokuta, Ogun State (Latitude 7.18°N, Longitude 3.45°E) and Kankara Katsina State (Latitude 11.93°N, Longitude 7.41°E), all of which are in Nigeria. Samples were prepared with various weight percentages (60–100 wt.%) clays and (0–40 wt.%) of agroforestry waste, with grain sizes between 212 and 600 µm. Raw materials and the developed refractory bricks were characterised using appropriate standard techniques. The chemical, mineralogical constituents and phases present in the microstructure were examined. Physical and thermo-mechanical properties were investigated. The insulating refractory bricks developed have porosity of 78.83% , cold crushing strength (CCS) 3.144 kN/m2 and thermal conductivity 0.04–0.046 W/(m∙K) that compare favourably with imported bricks 75–85%, 2.756 kN/m2 and 0.049 W/(m∙K) in both physical, mechanical and thermal properties respectively. The reason is that the agroforestry waste used (coconut shell), served to create the pores that improve insulation after burning. Also the ash that remains serves as reinforcement to improve the mechanical properties. The thermal behaviour of the bricks was studied using Finite Element Method and shows a strong correlation with the experimental findings. This indicates that the produced insulating bricks have the thermal properties required for insulation of furnaces

Strength, Water Absorption, Thermal and Antimicrobial Properties of a Biopolymer Composite Wound Dressing

Conventional wound material allows bacterial invasions, trauma and discomfort associated with the changing of the dressing material, and the accumulation of body fluid for wounds with high exudate. However, there is a shift from conventional wound dressing materials to polymeric nanofibers due to their high surface area to volume ratio, high porosity, good pore size distribution, which allows for cell adhesion and proliferation. There is an urgent need to synthesis a biodegradable composite that is resistant to bacterial infection. In this study, an electrospun polylactide (PLA) composite suitable for wound dressing, with enhanced antimicrobial and mechanical properties, was produced. The neat PLA, PLA/CH (10 wt.%), PLA/CH (5 wt.%), PLA/CHS (10 wt.%), PLA/CHS (5 wt.%), PLA/CH (2.5 wt.%) /CHS (2.5 wt.%) and PLA/CH (5 wt.%)/CHS (5 wt.%), were electrospun using 0.14 g/ml solution. Results show that crystallinity (67.6%) of neat PLA declined by 3.8% on the addition of 2.5 wt.% chitin/chitosan with improved hydrophilicity of the composite. The tensile strength of neat PLA (0.3 MPa) increased (0.6 MPa) with 2.5 wt.% chitin/chitosan addition. The slight increase in the glass transition temperature from 75°C for neat PLA to 78°C of the composite fibre, showed improved ductility. The fibres showed little beads, hence suitable for wound dressing. The electrospun mats have good water absorption capacity and strong resistance against Staphylococcus aureus. Good performance was attained at 5 wt.% of chitin, chitosan and hybrid reinforcements. Therefore, a PLA/chitin/chitosan composite is recommended as a wound dressing material

A Review on Lignin-Based Carbon Fibres for Carbon Footprint Reduction

Carbon fibers (CFs) are made mostly from a non-environmentally friendly polyacrylonitrile (PAN) and little from rayon. PAN-based CFs, require huge amount of energy for its production aside its contributions to the global CO2 emission. Therefore, there is recourse to a more environmentally friendly sources of CFs biomass. Recently lignin has been recognized as a potential renewable raw material for carbon fibers to replace PAN-based. The magnitude and quality of CO2 emission of lignin-based CFs are dependent on the processing route. On this premise; this review examines the various lignin-based CFs processing route adopted by researcher in the recent past to establish the most viable route with minimum carbon footprint emission. Outcome of the review shows that the major advantages of aromatic polymer (AP) generated precursor over PAN is the presence of higher quantity of guaiacyl units and oxygen content which makes the stabilization phase efficient and faster requiring less energy. Though there are several methods and options for the various stages of conversion of lignocellulosic biomass into CFs as highlighted in the study, establishing an optimum processing route will be a trade-off amongst various issues of concern; carcinogenic risk, carbon footprint emission, CFs Yield and mechanical strength of the CFs. Inferences from the study shows that the L-CF significantly produced reduced climatic impact in terms of CO2 emission