Changes in morphology and optical properties of polyvinyl alcohol foils induced by Congo red dye concentration and stretching degree

2014 ◽  
Vol 34 (4) ◽  
pp. 345-351 ◽  
Author(s):  
Carmen Beatrice Zelinschi ◽  
Iuliana Stoica ◽  
Dana Ortansa Dorohoi
Keyword(s):  
Optical Properties ◽  
Polyvinyl Alcohol ◽  
Congo Red ◽  
Order Parameter ◽  
Three Dimensional ◽  
Morphological Properties ◽  
Degree Of Crystallinity ◽  
Texture Parameters ◽  
Before And After ◽  
Red Dye

Abstract To establish correlations between the optical and morphological properties of anisotropic polyvinyl alcohol (PVA) foils containing Congo red (CR) dye in various concentrations, characteristics such as degree of crystallinity, dichroic ratio, order parameter, birefringence, surface morphology, and three-dimensional texture parameters were estimated before and after stretching. An increase in morphological and optical anisotropy with the degree of stretching has been evidenced for both pure and CR-containing PVA foils, this behavior being facilitated by the presence of the dye. The study of these properties lays the foundation for understanding the circumstances in which PVA foils containing CR can be used as polarizing filters.

Efficient removal of Congo red dye from aqueous solution by adsorbent films of polyvinyl alcohol/melamine-formaldehyde composite and bactericidal effects

2020 ◽  
Vol 255 ◽  
pp. 120062 ◽  
Author(s):  
Shahnawaz Ahmad Bhat ◽  
Fahmina Zafar ◽  
Aftab Hossain Mondal ◽  
Azar Ullah Mirza ◽  
Qazi Mohd Rizwanul Haq ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Polyvinyl Alcohol ◽  
Congo Red ◽  
Melamine Formaldehyde ◽  
Efficient Removal ◽  
Congo Red Dye ◽  
Bactericidal Effects ◽  
Red Dye

scholarly journals Effect of thermodenuding on the structure of nascent flame soot aggregates

2016 ◽  
Author(s):  
Janarjan Bhandari ◽  
Swarup China ◽  
Timothy Onasch ◽  
Lindsay Wolff ◽  
Andrew Lambe ◽  
...  
Keyword(s):  
Optical Properties ◽  
Ambient Air ◽  
Organic Coating ◽  
Index Of Refraction ◽  
Morphological Properties ◽  
Soot Particles ◽  
Internal Mixing ◽  
Soot Aggregate ◽  
Before And After ◽  
Particle Level

Abstract. The optical properties (light scattering and absorption) of soot particles depend on soot size and index of refraction, but also on the soot complex morphology and the internal mixing with other material at the single particle level. For example, freshly emitted (nascent) soot particles can interact with other materials in the atmosphere, materials that can condense on soot and coat it. This coating can affect the soot optical properties by refracting light, or by changing the soot aggregate structure. A common approach to studying the effect of coating on soot optical properties is to measure absorption and scattering values in ambient air and then measure them again after removing the coating using a thermodenuder. In this approach, it is assumed that: 1) Most of the coating material is removed; 2) charred organic coating does not add to the refractory carbon; 3) oxidation of soot is negligible; and 4) the pre-existing core soot structure is left unaltered despite potential oxidation of the core at elevated temperature. In this study, we investigate the validity of the last assumption, by studying the effect of thermodenuding on the structure of nascent soot. To this end, we analyze the morphological properties of laboratory generated nascent soot, before and after thermodenuding. Our investigation shows that there is only minor restructuring of nascent soot by thermodenuding.

scholarly journals Adsorption Behaviours of Anionic Azo Dye (Congo Red) from Aqueous Solution on Magnetic Expanded Graphite Material (EG@CoFe2O4) Composites

2020 ◽  
Vol 32 (4) ◽  
pp. 865-870
Author(s):  
Lam Van Tan ◽  
Nguyen Thi Hong Tham ◽  
Van Thuan Tran ◽  
Dao Thi To Uyen ◽  
Pham Gia Vu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Azo Dye ◽  
Expanded Graphite ◽  
Graphite Material ◽  
Experimental Conditions ◽  
Batch Mode ◽  
Before And After ◽  
Red Dye

In this paper, a potentiality of magnetic expanded graphite material (EG@CoFe2O4) for the adsorptive removal of Congo red, an anionic azo dye, from aqueous solution was studied. The experiments were carried out in batch mode in which various experimental conditions including contact time, initial dye concentration, adsorbent dosage and pH were varied and their influences on the adsorption yield were investigated. The surface of the adsorbent before and after the removal of the dye was characterized by using FT-IR analysis. Maximum adsorption of dye was achieved at pH 6. The adsorption capacity of Congo red onto EG@CoFe2O4 was found to be as high as 101.2 (mg/g), which is higher than the adsorption capacity of the CoFe2O4 (45.7 (mg/g)). These results suggested the use of expanded graphite materials as an efficient adsorbent for decontamination of Congo red dye from factory effluents.

scholarly journals Adsorption of Congo Red Dye from Aqueous Solution onto Natural and Modified Bauxite Clays

2017 ◽  
Vol 14 (1) ◽  
pp. 167-180 ◽  
Author(s):  
Baghdad Science Journal
Keyword(s):  
Congo Red ◽  
Batch Adsorption ◽  
General Shape ◽  
Congo Red Dye ◽  
Before And After ◽  
Equilibrium Data ◽  
Best Fitting ◽  
Enthalpy And Entropy ◽  
Gibb’S Free Energy ◽  
Red Dye

The adsorption behavior of congo red dye from its aqueous solutions was investigated onto natural and modified bauxite clays. Both bauxite and modified bauxite are primarily characterized by using, FTIR, SEM, AFM, and XRD. Several variables are studied as a function of adsorption including contact time, adsorbent weight, pH, ionic strength, particle size and temperature under batch adsorption technique. The absorbance of the solution before and after adsorption was measured spectrophotometrically. The equilibrium data fit with Langmuir model of adsorption and the linear regression coefficient R2 is found to be 0.9832 and 0.9630 for natural and modified bauxite respectively at 37.5°C which elucidate the best fitting isotherm model. The general shape of the adsorption isotherm of congo red on natural and modified bauxite is consistent with (H-type) on the Giles classification. Different thermodynamic parameters such as Gibb's free energy, enthalpy and entropy of the on-going adsorption process have also been evaluated. The thermodynamic analyses of the congo red adsorption on natural and modified bauxite indicate that the systems are endothermic in nature

Maps of 3D parameters for worn surfaces of composites PA and glass beads sliding on steel

2017 ◽  
Vol 69 (1) ◽  
pp. 42-51 ◽  
Author(s):  
Catalin Pirvu ◽  
Laura Maftei ◽  
Constantin Georgescu ◽  
Lorena Deleanu
Keyword(s):  
Surface Quality ◽  
Glass Bead ◽  
Three Dimensional ◽  
Glass Beads ◽  
Mean Deviation ◽  
Content Type ◽  
3D Texture ◽  
Texture Parameters ◽  
Before And After ◽  
Worn Surfaces

Purpose This paper aims to present the influence of glass bead concentration in a matrix of polyamide on wear and several three-dimensional (3D) parameters of the surface texture when the composite is sliding on steel in dry contact. Design/methodology/approach There were mold disks with the following concentrations in glass beads: 2.5, 5.0, 10, 20, 30 and 50 per cent. The mix of glass beads has diameters in the range of several microns to 50 microns. Tests were done on a pin-on-disk tribotester, in dry regime, for the following parameters: average pressure (1, 2 and 3 MPa) and sliding speed (0.5, 1.0 and 1.5 m/s). Zones of 500 × 500 μm were investigated from worn tracks generated on the composite disks, and the average values of several 3D texture parameters were analyzed. Findings The authors plotted maps indicating no correlation between the glass bead concentration and the parameters characterizing the surface quality (amplitude parameters and functional parameters). Composites with concentrations of 10[…]30 per cent glass beads generated worn surfaces with better quality as compared to composites with extreme concentrations: low (2.5 and 5 per cent) and high (50 per cent). Practical implications This set of parameters allows for evaluating the influence of regime parameters on the surface quality, by comparing the obtained values before and after sliding, and this evolution of roughness parameters could give recommendations for selecting the friction couple of materials for particular contacts that function with repeated starts and stops. Originality/value The results encourage the researchers to use a set of 3D texture parameters instead of “classical” two-dimensional parameters, the arithmetic mean deviation of the profile, Ra, because this set of parameters better evaluate the surface quality, especially for worn surfaces.

An effective method for determining the retention and distribution of cellulose nanofibrils in paper handsheets by dye labeling

TAPPI Journal ◽  
2018 ◽  
Vol 17 (03) ◽  
pp. 157-164 ◽  
Author(s):  
Shengdan Wang ◽  
Wenhua Gao ◽  
Kefu Chen ◽  
Jinsong Zeng ◽  
Jun Xu ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Congo Red ◽  
Kraft Pulp ◽  
Cellulose Nanofibrils ◽  
Standard Curve ◽  
Congo Red Dye ◽  
Mechanical Disintegration ◽  
Softwood Kraft Pulp ◽  
White Water ◽  
Red Dye

Cellulose nanofibrils (CNF) were prepared by cellulase in conjunction with mechanical disintegration from the bleached softwood kraft pulp and labelled by Congo red dye. The labelled CNF were used to investigate the retention and distribution of CNF in paper handsheets. The retention of the labelled CNF was obtained by measuring the absorbance of white water using an ultraviolet-visible spectrophotometer. The results showed that this method for measuring the retention was rapid, feasible, and sensitive, owing to the high correlation coefficient R2 (0.9993) of the standard curve. The labelled CNF showed even distribution in paper handsheets. The colorimetric values of paper handsheets were explored with a residual ink analyzer.

scholarly journals Functionalization of Congo red dye as a light harvester on solar cell

2020 ◽  
Vol 18 (1) ◽  
pp. 287-294
Author(s):  
Harsasi Setyawati ◽  
Handoko Darmokoesoemo ◽  
Irmina Kris Murwani ◽  
Ahmadi Jaya Permana ◽  
Faidur Rochman
Keyword(s):  
Solar Cell ◽  
Congo Red ◽  
Large Scale ◽  
High Efficiency ◽  
Solar Cell Device ◽  
Dye Sensitized ◽  
Congo Red Dye ◽  
Elemental Analyses ◽  
Red Dye ◽  
Solar Cell Technology

AbstractThe demands of ecofriendly technologies to produce a reliable supply of renewable energy on a large scale remains a challenge. A solar cell based on DSSC (Dye-Sensitized Solar Cell) technology is environmentally friendly and holds the promise of a high efficiency in converting sunlight into electricity. This manuscript describes the development of a light harvester system as a main part of a DSSC. Congo red dye has been functionalized with metals (Fe, Co, Ni), forming a series of complexes that serve as a novel light harvester on the solar cell. Metal-congo red complexes have been characterized by UV-VIS and FTIR spectroscopy, and elemental analyses. The performance of metal complexes in capturing photons from sunlight has been investigated in a solar cell device. The incorporation of metals to congo red successfully improved of the congo red efficiency as follows: Fe(II)-congo red, Co(II)-congo red and Ni(II)-congo red had efficiencies of 8.17%, 6.13% and 2.65%, respectively. This research also discusses the effect of metal ions on the ability of congo red to capture energy from sunlight.

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