scholarly journals Exhaustive valorization of cashew nut shell waste as a potential bioresource material

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
James Nyirenda ◽  
Kadango Zombe ◽  
George Kalaba ◽  
Chipo Siabbamba ◽  
Inyambo Mukela

AbstractIn this paper, we report extraction of cashew nut shell liquid (CNSL) from cashew nut shell waste (CNSW) and further use of residues for generation of activated carbon for removal of heavy metals and methylene blue (MB). Solvent extraction yielded 24.6 ± 0.4%, 38.2 ± 0.4% and 40.1 ± 0.9% for petroleum ether, hexane and ethanol respectively. Phytochemical screening showed presence of alkaloids, carbohydrates, saponins, phenols, tannins, flavonoids, amino acids, terpenoids, proteins, steroids, glycosides and carboxylic acids. The CNSL had a pH of 3.2, viscosity (104.6 ± 1.8 mPa s), moisture (6.5%), ash (1.6 ± 0.1%), refractive index (1.52 ± 0.001), specific density (0.9561 ± 0.0002 g/cm3), acid value (118.7 ± 9.2 mg KOH/g), free fatty acid value (60.1 ± 4.7%), saponification number (138.1 ± 3.2 mg KOH/g) and iodine value (188.1 ± 2.3 mgI 2/100 g). The average percentage removal of Cu (II), Pb (II), Cd (II) and Zn (II) was 99.4 ± 0.5, 95.4 ± 1.5, 99.5 ± 0.1, 98.4 ± 0.1%, and removal efficiency of MB at 50, 150, 250 and 350 mg/L was 99.63, 97.66, 96.48 and 94.81%, respectively. Equilibrium data were best described by the Freundlich isotherm model. The maximum monolayer adsorption capacity was 12.1 mg/g. The adsorption kinetics conformed to pseudo-second-order model. ∆G° was negative and a ∆H° of + 22.76 kJ/mol indicated that adsorption was endothermic. The ΔS° (+ 0.086 kJ/mol/K) showed that there was spontaneous interaction of the solution and adsorbate. These results show that CNSW is a potential bioresource for CNSL production for use in the paints, varnishes, surface coatings, agrochemicals and ethnomedicine industries. Residual shells can be exploited as fuels or converted to activated carbon for use as low-cost filters in water purification.

Author(s):  
Diego Caitano Pinho ◽  
Francisco Nivaldo Aguiar Freire ◽  
Felipe Alves Albuquerque Araújo ◽  
Kaio Hemerson Dutra ◽  
Edwalder Silva Teixeira ◽  
...  

Solar energy is the most promising energy source, due to its great availability and applicability in thermal energy applications. However, researchers still experience technological and economical challenge, since many systems that use this energy still have low efficiency and high cost. In this way, the development of new materials and technologies to increase the efficiency of solar thermal collectors is both a challenge and a necessity. In this context, the objective of this work is to obtain and analyze selective surfaces for solar thermal collectors, using cashew nut shell liquid. The cashew nut shell liquid can be classified as technical or natural, depending on the mode of extraction of cashew liquid. An experimental bench was built to simulate a flat plate solar collector under real operating conditions. For comparative purposes, the tests were performed between the cashew nut shell liquid and the commercial surface (MRTiNOX). In order to verify the structure morphology and the chemical composition of the surface, analyzes were performed by scanning electron microscopy. In order to identify the presence of components after the sintering process, the infrared analysis technique was used. To analyze the surface absorbance, the ultraviolet–visible spectroscopy absorbance technique was used. With the tests in real conditions, it was possible to perform the temperature measurements, and later, with the energy balance, the absorptivity, emissivity, and efficiency were calculated. The technical cashew nut shell liquid presented efficiency of 42.86%, while the MRTiNOX, 41.8%. In contrast, natural cashew nut shell liquid obtained efficiency of 31.28%. Thus, the use of technical cashew nut shell liquid, a low-cost regional product, was presented as a viable and satisfactory solution for cost reduction in solar thermal collectors.


2016 ◽  
Vol 2 (2) ◽  
pp. 55-61
Author(s):  
N. T. Nevaditha ◽  
S. Gopalakrishnan ◽  
C. V. Mythili

Biomaterials, chemicals and energy from renewable resources have been the object of considerable interest in recent years. Vegetable oils are one of the cheapest and most abundant biological sources available in large quantities and their use as starting materials has numerous advantages such as low toxicity, inherent biodegradability and high purity. They are considered to be one of the most important classes of renewable resources for the production of bio-based thermosets. As a substitute to the use of conventional reinforcing synthetic resins, biobased resins were synthesized from cardanol, renewable and low cost industrial grade oil obtained by vacuum distillation of Cashew Nut Shell Liquid (CNSL), an abundant agricultural byproduct of cashew industry. On the other hand to further expand the field of application, cardanol-based novolac scaffolds, used in the formulation of thermosetting resins by blending with a conventional epoxy resin, especially designed to be compatible with conventional bisphenol- A epoxy resins. In the present study resins have been synthesized by condensing diazotized p-anisidine cardanol dye with urea, resorcinol and furfural as condensing agent.. The resins have been characterised by FT-IR, 1H-NMR and XRD studies. Thermal behavior of the resins has been studied by Thermogravimetric Analysis (TGA) and Differential thermal analysis (DTA). The DTA, SEM and XRD data indicated the percentage of crystallinity associated with the thermal stability of the resins.


2007 ◽  
Vol 15 (1) ◽  
pp. 75-82 ◽  
Author(s):  
Lubi C. Mary ◽  
Eby Thomas Thachil

2021 ◽  
pp. 009524432199040
Author(s):  
Isabela Pinto Ferreira ◽  
Alex da Silva Sirqueira ◽  
Taiane Andre dos Santos ◽  
Monica Feijo Naccache ◽  
Bluma Guenther Soares

Research on bio-plasticizers is a topic of strategic interest in polymer blends. A bio-plasticizer, cashew nut shell liquid (CNSL), was studied in blends of ethylene-vinyl acetate copolymer (EVA) and styrene-butadiene-styrene copolymer (SBS). In the literature does not report the addition of plasticizers to SBS/EVA blend. Statistical analyses showed that there was a significant difference in mechanical properties (tension at break, hardness and elongation at break) vs. the unplasticized blend. The minimum CNSL concentration required for a statistical difference was 10 phr. The Carreau-Yasuda rheological model was used to obtain rheological parameters in these blends. The plasticizing influence of CNSL was confirmed by rheology. The effects of CNSL on creep and recovery were evaluated for the SBS/EBA blends. Burger´s model explained well SBS/EVA creep compliance. Moreover, its parameters (Newtonian dashpots and Hookean springs) were evaluated as a function of the CNSL concentrations. The bio-plasticizer concentration influenced significant correlations among the rheological creep-recovery tests, thus enabling a considerable increase in the elastic phase. Experimental creep-recovery data and curve fit were in good agreement.


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