Delta Acid Research Articles

Adsorptive performance of aminonaphthalenesulfonic acid modified magnetic-graphene oxide for methylene blue dye: Mechanism, isotherm and thermodynamic studies

In this research, a new aminonaphthalenesulfonic acid modified magnetic-graphene oxide (Fe3O4@GO@AHSA) was fabricated via in situ co-precipitation process followed by a covalent functionalization of Fe3O4@GO with aminonaphthalenesulfonic acid (AHSA) via amidation reaction. Fe3O4@GO@AHSA was featured by Zeta potential, FTIR, SEM, XRD, and TGA, then utilized in methylene blue (MB) adsorption from an aquatic media. The optimum removal efficiency of Fe3O4@GO@AHSA was assessed by batch method at different variables such as adsorbent dose (0.01–0.05 g), pH (2–8), adsorption time (1–1440 min), initial concentration of MB (25–300 mg/L), and temperature (25–45 °C). Accordingly, 0.03 g Fe3O4@GO@AHSA dose, pH: 7, contact time: 240 min at 25 °C were found to be the best optimal conditions, and a maximum experimental adsorption capacity of Fe3O4@GO@AHSA toward was 220.1 mg/g. Three nonlinear isotherm and kinetic models were utilized to assess the equilibrium experimental adsorption data. The findings show that the removal performance fits a Longmire isotherm and pseudo-second-order kinetic models. Besides, the result revealed that the maximum monolayer adsorption of MB on Fe3O4@GO@AHSA was 286.4 m/g. Based on thermodynamic results, the MB adsorption on Fe3O4@GO@AHSA nanocomposite was exothermic and a feasible process. The reusability tests displayed that the Fe3O4@GO@AHSA nanocomposite can be regenerated and reused up to the fourth cycle successfully for the uptake of MB pigment. Finally, this research indicates that the Fe3O4@GO@AHSA nanocomposite has a robust adsorption performance for MB dye from an aqueous medium.

Single-step synthesis and energy-efficient coloration of wool textiles with poly(amino naphthalene sulfonic acid)-based dyes by oxidation polymerization

In the context of sustainability, energy-efficient low-temperature dyeing with non-toxic polymeric dyes is attractive. In this work, a single-step method of simultaneous synthesis of polymeric dyes from non-toxic amino-naphthalene sulfonic acids (ANSAs) by the oxidation polymerization and energy-efficient coloration of wool fabric was developed. The studied monomers are 7-amino-1,3-naphthalene monopotassium disulfonate (ANSA-1), 4-amino-1-naphthalene sulfonic acid (ANSA-2), and 5-amino-2-naphthalene sulfonic acid (ANSA-3). The prepared polymeric dyes were characterized by UV–vis, Fourier transform infrared (FT-IR), and mass spectrometry, and gel permeation chromatography (GPC). The mass spectra suggest that oxidation treatment of ANSA-1 formed only dimers but the other two ANSAs formed polymers, whereas the GPC data demonstrated successful polymerization of all three ANSAs. The treated fabrics were characterized by thermogravimetric analysis, and FTIR and reflectance spectroscopies. The treatment parameters, including the monomer and oxidant concentrations, treatment pH, temperature, and time, affected the shade of the color produced and its intensity. The optimum conditions for dyeing with ANSAs were 50 °C, 120 min, and a 1:1 monomer to oxidant ratio. The treatment with these ANSAs produced various colors in the fabric including tonal changes. The colorfastness to washing increased with an increase in the treatment temperature and time. The shade of color produced and the color intensity were dependent on the position of the substituent sulfonate groups in the amino-naphthalene compounds. This developed treatment can be used for the energy-efficient dyeing of wool and other polyamide fibers with good colorfastness to washing.

Structure and Bioactive Properties of Novel Textile Dyes Synthesised by Fungal Laccase.

Novel sustainable processes involving oxidative enzymatic catalysts are considered as an alternative for classical organic chemistry. The unique physicochemical and bioactive properties of novel bio-products can be obtained using fungal laccase as catalyst. Among them are textile biodyes synthesised during oxidation of substrates belonging to the amine and methoxy organic derivatives. The process of synthesis occurs in mild conditions of pH, temperature, and pressure, and without using harmful oxidants. The effect of fungal laccase activity on the substrates mixture transformation efficiency was analysed in terms of antimicrobial dye synthesis on a large scale. Three new phenazine dyes, obtained in the presence of laccase from Cerrena unicolor, were studied for their structure and properties. The phenazine core structure of the products was a result of tri-molecular transformation of aminomethoxybenzoic acid and aminonaphthalene sulfonic acid isomers. One of the compounds from the synthesised dye, namely 10-((2-carboxy-6-methoxyphenyl)amino)-11-methoxybenzo[a]phenazine-8-carboxylic acid, was able to inhibit the growth of Staphylococcus aureus. The high concentration of substrates (5 g/L) was efficiently transformed during 72 h in the mild conditions of pH 4 with the use of laccase with an activity of 200 U per g of the substrates mixture. The new bioactive dye exhibited excellent dyeing properties with concomitant antibacterial and antioxidative activity. The proposed enzyme-mediated synthesis represents an alternative eco-friendly route for the synthesis of novel antimicrobial compounds with high importance for the medical textile industry.

Amino-substituted naphthalene sulfonic acid/graphene composite as metal -free catalysts for oxygen reduction reactions

Composites of reduced graphene oxide (rGO) and conducting polymers synthesized from 8-amino-2-naphthalene sulfonic acid (8-ANSA), 5-amino-1-naphthalene sulfonic acid (5-ANSA), 2-amino-1-naphthalene sulfonic acid (2-ANSA), and 4-amino-1-naphthalene sulfonic (4-ANSA) were prepared for use as an electrocatalyst in oxygen reduction reaction (ORR). The electrocatalytic activities were examined in oxygen saturated 0.1 M KOH solution using cyclic and linear sweep voltammetry. The best performing polymer composite was found to be GC/poly(8-ANSA)/rGO, with an enhanced electrocatalytic activity over the rGO only and poly(8-ANSA) only films. More than 100 mV positive shift in the onset potential and 1.6 times increase in current density were observed. The catalytic activity of 2-ANSA, 4-ANSA, 5-ANSA, and 8-ANSA was also validated by density functional theory (DFT). Our calculations predict a much better catalytic activity for 8-ANSA than that of 2-ANSA, 4-ANSA, and 5-ANSA. KEY WORDS : Poly(amino naphthalene sulfonic acid), Reduced graphene oxide, Oxygen reduction reaction, Electrocatalyst Bull. Chem. Soc. Ethiop. 2019 , 33(2), 359-372. DOI: https://dx.doi.org/10.4314/bcse.v33i2.16

A Simple Method To Synthesize Poly(Aminonaphthalene Sulfonic Acid) and Silver Nanocomposite and Its Characterization

A Simple Method To Synthesize Poly(Aminonaphthalene Sulfonic Acid) and Silver Nanocomposite and Its Characterization

Studies on Synthesis and Dyeing Preformance of Acid Dyes Based on 4,7-Dihydroxy-1,10-Phenanthroline-2,9-Dione

Some new azo acid dyes were prepared by coupling various diazotized acid components such as anthranilic acid, sulphanilic acid, laurent acid, peri acid, tobias acid, H-acid, J-acid, gamma acid, sulphotobias acid, 4-aminotoluiene-3-sulphonic acid, 5-sulpho- anthranilic acid, 2-naphthylamine-3,6,8-trisulphonic acid, bronner acid, metanilic acid and cleve acid with 4,7-dihydroxy-1,10-phenanthroline-2,9-dione. The dyes were characterized by elemental, IR and TLC analyses. Their dyeing performance as acid dyes has been assessed on viscose rayon, wool and cotton fibres.

Novel electrically conductive and ferromagnetic composites of poly(aniline‐co‐aminonaphthalenesulfonic acid) with iron oxide nanoparticles: Synthesis and characterization

AbstractNanocomposites of iron oxide (Fe3O4) with a sulfonated polyaniline, poly(aniline‐co‐aminonaphthalenesulfonic acid) [SPAN(ANSA)], were synthesized through chemical oxidative copolymerization of aniline and 5‐amino‐2‐naphthalenesulfonic acid/1‐amino‐5‐naphthalenesulfonic acid in the presence of Fe3O4 nanoparticles. The nanocomposites [Fe3O4/SPAN(ANSA)‐NCs] were characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), X‐ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, elemental analysis, UV–visible spectroscopy, thermogravimetric analysis (TGA), superconductor quantum interference device (SQUID), and electrical conductivity measurements. The TEM images reveal that nanocrystalline Fe3O4 particles were homogeneously incorporated within the polymer matrix with the sizes in the range of 10–15 nm. XRD pattern reveals that pure Fe3O4 particles are having spinel structure, and nanocomposites are more crystalline in comparison to pristine polymers. Differential thermogravimetric (DTG) curves obtained through TGA informs that polymer chains in the composites have better thermal stability than that of the pristine copolymers. FTIR spectra provide information on the structure of the composites. The conductivity of the nanocomposites (∼ 0.5 S cm−1) is higher than that of pristine PANI (∼ 10−3 S cm−1). The charge transport behavior of the composites is explained through temperature difference of conductivity. The temperature dependence of conductivity fits with the quasi‐1D variable range hopping (quasi‐1D VRH) model. SQUID analysis reveals that the composites show ferromagnetic behavior at room temperature. The maximum saturation magnetization of the composite is 9.7 emu g−1. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007

Studies on Synthesis and Dyeing Preformance of Acid Dyes Based on 4,7‐Dihydroxy‐3,8‐di‐α‐naphthylazo‐1,10‐phenanthroline‐2,9‐Dione

Some new azo acid dyes were prepared by coupling various diazotized acid components such as anthranilic acid, sulphanilic acid, laurentacid, peri acid, tobias acid, H‐acid, J‐acid, gamma acid, sulphotobias acid,4‐aminotoluiene‐3‐sulphonic acid, 5‐sulpho‐ anthranilic acid, 2‐naphthylamine‐3,6,8‐trisulphonic acid, bronner acid, metanilic acid and cleve acid with 4,7‐dihydroxy‐3,8‐di‐α‐naphthylazo‐1,10‐phenanthroline‐2,9‐dione. The dyes were characterized by elemental, IR and TLC analyses. Their dyeing performance as acid dyes has been assessed on viscose rayon, wool and cotton fibres.

Biodegradation of benzidine based dye Direct Blue-6 by Pseudomonas desmolyticum NCIM 2112

Pseudomonas desmolyticum NCIM 2112 was able to degrade a diazo dye Direct Blue-6 (100 mg l −1) completely within 72 h of incubation with 88.95% reduction in COD in static anoxic condition. Induction in the activity of oxidative enzymes (LiP, laccase) and tyrosinase while decolorization in the batch culture represents their role in degradation. Dye also induced the activity of aminopyrine N-demethylase, one of the enzyme of mixed function oxidase system. The biodegradation was monitored by UV–Vis, IR spectroscopy and HPLC. The final products, 4-amino naphthalene and amino naphthalene sulfonic acid were characterized by GC–mass spectroscopy.

Spectroscopic and semiempirical studies of the phototropic species of 8-amino-5,8′-azo-bis-naphthalene-2-sulphonic acid

Structural study of the azo compound obtained as a result of diazotization and coupling of 8-amino-naphthalene-2-sulfonic acid (Cleve's acid), has been performed by the spectroscopic methods 1H NMR and FTIR. UV–vis spectra of 8-amino-5,8′-azo-bis-naphthalene-2-sulphonic acid (CA-CA) were measured in water environment at different pH values and at a constant ionic strength. On the basis of the NMR, FTIR as well as on the grounds of a comparison of the experimental UV–vis spectra with those obtained by the MM/ PM5 in water followed by ZINDO method calculation, geometry of the CA-CA molecule in water solution has been proposed. Moreover, the value of the first dissociation constant of the dye has been determined (2.75×10 −2).

Synthesis and characterization of self‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) nanotubes

AbstractSelf‐doped poly(aniline‐co‐aminonaphthalene sulfonic acid) (PANI‐ANSA) was synthesized by the copolymerization of 5‐aminonaphthalene‐2‐sulfonic acid (ANSA) and aniline. Scanning electron microscopy and transmission electron microscopy showed that the morphology of PANI‐ANSA synthesized at a high molar ratio of aniline to ANSA was nanotubular, but at a low molar ratio, only a granular morphology formed. A possible formation mechanism for nanotubes was proposed. PANI‐ANSA had better thermal stability than HCl‐doped polyaniline; the highest onset decomposition temperature was as high as 340°C because of SO3H linked with the polymer backbone by a covalent bond. PANI‐ANSA was partially soluble in basic solutions, and its conductivity was between 10−2 and 10−4 S/cm, depending on the sulfonation degree. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 1297–1301, 2003

Magnetic properties of molecular systems: A nonlocal spin density functional study

A new class of molecular magnets based on aniline and aminonaphthalene sulfonic acid was previously reported. In the present work, a nonlocal density functional theory study was performed on simple molecular models, to determine the mechanism that stabilizes the parallel alignment of the spin component. The role played by transition metals on the magnetic properties of this kind of systems was also studied within this approximation. The results obtained show a high sensitivity of the magnetic coupling on the molecular geometry as well as on the nature and oxidation state of the metallic atom.

Density functional theory study of magnetic coupling between Cu atoms and aniline molecules

To study the influence of transition metal atoms on the magnetic properties of compounds based on aniline and aminonaphthalenesulfonic acid, we explore theoretically a simple model based on stacked aniline molecules (radicals) and intercalated Cu atoms. Calculations were performed within the non-local spin density approximation with Becke's exchange functional and the gradient-corrected functional of Lee, Yang and Parr (BYLP) using the DMol program. The results reveal a surprisingly strong interaction between the Cu s and d valence electrons with the molecular π states, leading to a ferromagnetic coupling in the case of Cu0 and CuII with molecular aniline. In the case of aniline radicals, the coupling is ferromagnetic for Cu0 and ferrimagnetic for CuII. Stacks involving three and four aniline molecules show localization of the spin density to the molecules adjacent to the Cu atom.

Ab initio study of magnetic coupling in aniline-based molecules: Role of Fe atoms

Our interest is the study of magnetic properties of organic compounds. We have previously reported a new class of organic magnets based on aniline and aminonaphthalenesulfonic acid. In this work, we explore theoretically a simple model based on superposed aniline molecules (radicals) and Fe atoms to determine the mechanism that stabilizes the parallel alignment of the electronic spin. Calculations were performed within the non-local spin density approximation with Becke's exchange functional and the gradient-corrected functional of Lee, Yang and Parr (BYLP) using the DMol program. The results show a high sensitivity of the magnetic properties to the oxidation state of the metal: intercalated between molecular aniline the total spins are 1, 0 and 1/2 for Fe0, FeII and FeIII, and between radicals the spins are 0, 0 and 1/2, respectively. This opens the possibility of creating molecular magnets by doping purely organic materials with transition metal atoms or ions.

Study of ferromagnetic properties of molecular magnets based on aminonaphthalenesulfonic acid and aniline

Our interest is the study of magnetic properties on organic compounds. We have previously reported a new class of molecular magnets based on aminonaphthalenesulfonic acid and aniline. In this work we explore theoretically a simple model based on superposed aniline molecules and the goal is to determine the mechanism that stabilizes the parallel alignment of the spin component. Calculations were performed within the local density approximation (LDA). The results obtained show a high sensitivity of the magnetic coupling relative to translations and rotations of one aniline molecule with respect to the other. Distances between both NH units have also a great importance in the spin stabilization. These results are in good accordance with some synthesis difficulties.

Magnetometric analysis of a new class of copolymer magnets based on aminonaphthalenesulfonic acids

Recently, a new class of copolymer based on aminonaphthalenesulfonic acid and aniline were synthesized. By means of a VSM, an AGFM and a SQUID, it was shown that these materials are ferromagnetic, above room temperature. These results, consistent with temperature dependent EPR tests and magneto-optic experiments, support the achievement of high temperature magnets (T < 600 K) using only light elements of Mendeleev classification, considered as a scientific challenge.

Drug‐Biomolecule Interactions: Fluorescence Studies on Interaction of Aminonaphthalenesulfonic Acid Derivatives with Serum Albumins

The binding of the three aminonaphthalenesulfonic acid derivatives to human and bovine serum albumins was studied by measuring the fluorescence enhancement of the compounds. The number of binding sites of human and bovine serum albumins for these compounds appears to be one and two, respectively, under the experimental conditions. As the molar ratio of the fluorescent compounds to bovine serum albumin increased, the binding sites appeared to increase for the compounds. The quenching of the native fluorescence of albumin was examined by the successive addition of methanolic solutions of these compounds. 1‐Anilinonaphthalene‐8‐sulfonate quenched the protein fluorescence to a greater extent than the other compounds studied, indicating that 1‐anilinonaphthalene‐8‐sulfonate molecules are bound more closely to the tryptophan residues of albumin. The finding that the three compounds did not quench the fluorescence of tryptophan dissolved in water indicates no direct molecular interaction between tryptophan and the three fluorescent probes. The driving force for binding may be due to the structural characteristics of the amino acid sequence surrounding the tryptophan residues.

Determination of nitrite and nitrate in some horticultural and meat products and in samples of soil.

AbstractThis study of quantitative determination of nitrite and nitrate contents is based on spectrophotometric measurement of the red colour formed when sulphanilic acid is diazotised by the nitrite to be determined and coupled to 1‐naphthylamine‐7‐sulphonic acid (Cleve's acid 1‐7). Nitrate is first reduced to nitrite in a cadmium reducing column.Good results have been obtained with some horticultural and meat products and samples of soil.

Factors influencing the colorimetric determination of nitrite with Cleve's acid

The determination of nitrite with Cleve's acid has been investigated; the influence of composition of reagents and several experimental conditions have been evaluated. It is shown that provided the standards used to prepare the calibration graph and samples are treated in a similar way, then the choice of conditions may largely be left to the operator. A recommended procedure is given.