Open Access Original Research Article

Contribution to the Study of Phosphorus Adsorption Kinetics on the Superficial Sediments of a Recently Development Artificial Estuary: Vridi Channel (Côte d'Ivoire)

N’da Samuel, Yao Marcel Konan, Trokourey Albert

Chemical Science International Journal, Page 1-22
DOI: 10.9734/CSJI/2021/v30i230214

The aim of this study is to characterize phosphates adsorption kinetics on the superficial sediments of Vridi channel from its new hydromorphology. So, three scenarios have been carried out taking account the different waters seasons of this estuary by using pH and temperature as relevant parameters. In the first scenario, the experiments carried out at pH = 8 and T = 20°C to simulate phosphates adsorption on these sediments in its great cold season. In the second, the experiments carried out at pH = 8 and T = 25° C to simulate phosphates adsorption on these substrates in its hot season and small cold season. In the third, the experiments carried out at pH = 7 and T = 30°C to simulate phosphates adsorption on these sediments in its flood season. The experiences were carried out according to US EPA/530/SW-87/006-F protocol. KH2PO4 solutions were used as phosphates synthetic solutions. The experimental data were modeling by Lagergeen kinetics model (pseudo-order 1), Blanchard kinetics model (pseudo-order 2), Elovich kinetics model, Weber and Morris kinetics model and, external diffusion kinetics model. The results have showed phosphates adsorption on these sediments increase in the experiments carried out at pH = 8 and T = 20°C to those carried out at pH = 7 and T = 30°C. All experimental data have been well modeling by Blanchard kinetics model. So, these phosphates adsorption kinetics are pseudo-order 2 and the chemisorption is the dominant mechanism. The results obtained by the experimental data modeling by Weber and Morris kinetics model and external diffusion kinetics model showed that this process is not limiting by the molecular diffusion process. The experimental data have been again well modeling by Elovich kinetics model. That has confirmed the chemisorption character of this adsorption, and showed this chemisorption is activated.

Open Access Original Research Article

Evaluation of Secondary Metabolites and Antioxidant Activity of Water, Ethyl Acetate and Hexane Fractions from the Mangrove Young Leaves Sonneratia alba

Verly Dotulong, Djuhria Wonggo, Lita A. D. Y. Montolalu

Chemical Science International Journal, Page 23-32
DOI: 10.9734/CSJI/2021/v30i230215

The fractions from young leaves of mangrove Sonneratia alba was studied for its associated secondary metabolites and antioxidant activities. The objective of this study was to determine the secondary metabolite components and antioxidant activity of water, ethyl acetate, and hexane fractions of the young leaves of mangrove S. alba. The fraction was obtained from dry powder of young leaf S.alba using continuous fractionation of crude extracts. The crude extract was attained by 2 extraction methods (soxhlet and maceration) and 2 extraction solvents (methanol and ethanol). Secondary metabolites analyses were qualitatively conducted to detect the presence or absence of phenols, flavonoid, tannin, steroid, triterpenoid and alkaloid. Total phenols were measured using Folin Ciocalteau reagents and gallic acid standard curves whereas antioxidant activity were analyzed using DPPH method (1- 1-diphenil-2-picrihydrasil). Results showed that all fractions contained secondary metabolite components tested. The highest rendement was found in the water fraction fromsoxhletation extract with methanol (6.36±0.29%). The total phenol values were found the highest in the ethylacetatefraction from macerated extract with ethanol (352±9.77 mgGAE/g). Stronger antioxidant activity was also found in ethylacetate  fraction as indicated by the small value of IC50 DPPH namely the ethylacetate fraction with soxhletation extract with ethanol  (3.43±0.25 µg / mL). The results of this study indicate that the semipolar fraction (ethylacetate fraction) has more potential as a source of natural antioxidants.

Open Access Original Research Article

Preparation and Characterization of Biacetyl Monoxime Hydrazone Salicylidene Complexes of Lanthanoid (III) Ions

Sharad Sankhe, Sainath Bhavsar

Chemical Science International Journal, Page 33-39
DOI: 10.9734/CSJI/2021/v30i230216

The 1:3 complexes of lanthanoid (III) ions as Nd(III), Sm(III), Tb(III) and La(III) with biacetyl monoxime hydrazone salicyalidene have been prepared and characterized by elemental analysis, IR, PMR, electronic spectra, molar conductance and magnetic properties. All these complexes  of  Ln(III)  complexes  are  found  to  be  unique  in  infrared  and  solubility  to  the methanol, chloroform, DMF, DMSO solvents. The results show that the biacetyl monoxime hydrazone salicyalidene ligand acts as a  bidentate monobasic donor, coordinating through the azomethine nitrogen and deprotonated oximino proton.

Open Access Original Research Article

Photodegradation Kinetics and Color Removal of 2-(4-hydroxyphenylazo) Benzoic Acid by Advanced Oxidation Processes

Yeliz Karaman, Emine Baltaci

Chemical Science International Journal, Page 40-49
DOI: 10.9734/CSJI/2021/v30i230217

Degradation kinetics and color removal of 2-(4-hydroxyphenylazo)benzoic acid azo dye by the hydrogen peroxide/ultraviolet irradiation and sodium hypochlorite/ultraviolet irradiation processes were carried out in Spectroline CM-10A Model ENF-260C/FE photoreactor which has ultraviolet lamps irradiating at 254 and 365 nm wavelengths. All experimental studies were performed at room temperature in 0.04 M Britton Robinson buffer (pH 2-12). For this purpose, the degradation kinetics of 2-(4-hydroxyphenylazo)benzoic acid was investigated depending on pH, initial dye concentration and hydrogen peroxide concentration. Optimum pH and hydrogen peroxide concentration were determined as pH 10 and 3.57x10-2 M, respectively, for 3.5x10-5 M 2-(4-hydroxyphenylazo)benzoic acid. Optimum pH value in 1.55x10-3 M sodium hypochlorite medium has been found as pH 8 for 3.5x10-5 M azo dye. These methods used for degradation of dye are compared, it is concluded that sodium hypochlorite/ultraviolet irradiation and sodium hypochlorite methods are more effective than hydrogen peroxide/ultraviolet irradiation and hydrogen peroxide methods because of color removal of 83% and 64%, respectively.

Open Access Original Research Article

Extraction and Characterization of Silver Nitrate Modified Biopolymer and its Antimicrobial Mode of Action

Jeje O. Ayorinde, Osula J. Eghosa

Chemical Science International Journal, Page 50-62
DOI: 10.9734/CSJI/2021/v30i230218

Biopolymer (chitosan) was isolated from crab shell waste through the processes of demineralization, deproteinization, decolourization and deacetylation. The resulting chitosan (CHS) was further treated with silver nitrate (AgNO3) solution at various concentrations (0.5, 1.0 and 1.5 M) in order to enhance the antimicrobial activity of chitosan. The crab shell powder (CSP) and (CHS) were characterized using X-ray Diffractometer (XRD), Fourier Transform Infrared (FT-IR), and Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS). The antimicrobial mode of action of AgNO3 treated chitosan was performed using serial dilution (1:2) technique for minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) and tested against four microorganisms (Escherichia coli, Klebsiella pneumonia, Staphlococcusaureus and Pseudopodium). The result of proximate analysis of CHS and chitin (CHN) showed % crude protein to be 12.24±001 and 20.54±0.03 respectively, % ash was found to be 4.1±0.01 for CHS and 3.80±0.01 for CHN. The FTIR spectra of CHS and CHN showed their characteristic absorption peaks and the diffractograms of CSP and CHS showed CaCO3 to be the major mineral present in the samples. The antimicrobial evaluation revealed that untreated chitosan extract (UCHSE) showed no antimicrobial activity against the four tested microorganisms. The results of MIC and MBC showed that the organisms responded to the antimicrobial agent at different dilution concentration. It was observed that CHS treated with 0.5 M AgNO3 (0.5 SNCHSE) inhibited the growth of E. coli at 1000 µg/mL, S. aureus at 500 µg/mL while it exhibited bactericidal (MBC) activity against all the organisms at 1000 µg/mL.