scholarly journals Optimum conditions for the synthesis of high solubility carboxymethyl chitosan

2014 ◽  
Vol 10 (4) ◽  
Author(s):  
Mardiyah Kurniasih ◽  
Purwati Purwati ◽  
Dadan Hermawan ◽  
Muhamad Zaki
Keyword(s):  
Reaction Time ◽  
Carboxymethyl Chitosan ◽  
Monochloroacetic Acid ◽  
Optimum Conditions ◽  
High Solubility ◽  
Synthesis Conditions ◽  
Acid Ratio ◽  
Full Factorial Experimental Design ◽  
Full Factorial

A research on optimizing the synthesis conditions to obtain carboxymethyl chitosan with the highest solubility in 1%(v/v) acetic acid solvent have been performed. Optimization was performed by varying: the concentration of NaOH during alkalizing the chitosan, chitosan: monochloroacetic acid ratio, temperature and reaction time. This study uses a full factorial experimental design. The results showed that the highest solubility was found in 40% (w/v) NaOH concentration, chitosan to monochloroacetic acid ratio of 1:7, reaction temperature of 80°C and reaction time at 4 hours with the solubility up to 63.78 mg /mL. IR and 1H-NMR spectra showed that the synthesis gave result to carboxymethyl chitosan. Results of physical characterization of carboxymethyl chitosan at the highest solubility showed the value of water content, ash content, molecular weight, and swelling effects up to 14.27%, 8.48%, 2,86978 x 105 g/mol; and 884.19%, respectively.

Optimised photocatalytic degradation of a mixture of azo dyes using a TiO2/H2O2/UV process

2012 ◽  
Vol 65 (8) ◽  
pp. 1392-1398 ◽  
Author(s):  
Soraya Moreno Palácio ◽  
Fernando Rodolfo Espinoza-Quiñones ◽  
Aparecido Nivaldo Módenes ◽  
Diego Ricieri Manenti ◽  
Cláudio Celestino Oliveira ◽  
...  
Keyword(s):  
Photocatalytic Degradation ◽  
Azo Dyes ◽  
Irradiation Time ◽  
Optimum Conditions ◽  
Order Model ◽  
Kinetic Rate Constant ◽  
Kinetic Rate ◽  
Full Factorial Experimental Design ◽  
Two Parameters ◽  
Full Factorial

The aim of the present study was to optimise the photocatalytic degradation of a mixture of six commercial azo dyes, by exposure to UV radiation in an aqueous solution containing TiO2-P25. Response surface methodology, based on a 32 full factorial experimental design with three replicates was employed for process optimisation with respect to two parameters: TiO2 (0.1–0.9 g/L) and H2O2 (1–100 mmol/L). The optimum conditions for photocatalytic degradation were achieved at concentrations of 0.5 g TiO2/L and 50 mmol H2O2/L, respectively. Dye mineralisation was confirmed by monitoring TOC, conductivity, sulfate and nitrate ions, with a sulfate ion yield of 96% under optimal reactor conditions. Complete decolorisation was attained after 240 min irradiation time for all tested azo-dyes, in a process which followed a pseudo-first kinetic order model, with a kinetic rate constant of approximately 0.018 min−1. Based on these results, this photocatalytic process has promise as an alternative for the treatment of textile effluents.

scholarly journals Optimizing Conditions to Cholesterol Adsorbed with Carboxymethyl Chitosan

Molekul ◽  
2016 ◽  
Vol 11 (1) ◽  
pp. 112 ◽  
Author(s):  
Mardiyah Kurniasih ◽  
Dwi Kartika ◽  
Riyanti Riyanti
Keyword(s):  
Acetic Acid ◽  
Water Content ◽  
Contact Time ◽  
Carboxymethyl Chitosan ◽  
Ash Content ◽  
Distilled Water ◽  
Factorial Experimental Design ◽  
Cholesterol Ratio ◽  
Full Factorial Experimental Design ◽  
Full Factorial

A research on optimizing conditions to cholesterol adsorbed have been performed. Optimization was performed by varying: contact time, adsorbent weight and temperature of the system's. A full factorial experimental design was used in this study. Characterization performed on the synthesized chitosan and carboxymethyl chitosan including FTIR, water content, ash content, solubility, porosity, and swelling effect. The results showed that carboxymethyl chitosan able to adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:200) with a contact time of 90 minutes at temperature of 40 °C. Meanwhile, at a temperature of 55 °C carboxymethyl chitosan capable of adsorb cholesterol under conditions optimal adsorbent with cholesterol ratio (1:300) with a contact time of 30 minutes. Chitosan and carboxymethyl chitosan synthesized has a water content of 7.4 and 10.2%, ash content of 0.14 and 2.29%, solubility in distilled water at 1.10-5and 1.98.10-3%, solubility in acetic acid 0.02 and 0.04%, porosity at 88.3% and 88.8%, and swelling at 163.13 and 182.98%.

Preparation and Characterization of Magnesium Borate Whisker

2013 ◽  
Vol 662 ◽  
pp. 481-484
Author(s):  
Zhi Liang Jin ◽  
Xu Jing ◽  
Yuan Hong ◽  
Xue Ying Nai ◽  
Li Wu
Keyword(s):  
Reaction Time ◽  
Molten Salt ◽  
Reaction Temperature ◽  
High Performance ◽  
Raw Materials ◽  
Price Ratio ◽  
Magnesium Borate ◽  
Synthesis Conditions ◽  
Ft Ir

Being a new whisker products with high performance to price ratio, magnesium borate whiskers with a length of 10 - 50μm and a diameter of 0.5 - 2μm were prepared by molten salt and characterized by XRD, FT - IR, SEM and chemical titration. The experiments show that the synthesis conditions are as follows: raw materials ratio: Mg:B:flux =1:11.05:1-3.5(mol); reaction temperature: 800 - 950°C;reaction time:6 - 10hours; flux: NaCl、KCl or NaOH.

Synthesis and Characterization of N, O-Carboxymethyl Chitosan

2013 ◽  
Vol 791-793 ◽  
pp. 48-51
Author(s):  
Hao Zhang ◽  
Ying She ◽  
Xue Zheng ◽  
Jun Wen Pu
Keyword(s):  
Fourier Transform ◽  
Infrared Spectrum ◽  
Potentiometric Titration ◽  
Powder Diffraction ◽  
Fourier Transform Infrared ◽  
Carboxymethyl Chitosan ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Synthesis Conditions

N, O-Carboxymethyl chitosan (N, O-CMC) was synthesized in this study, and the properties of N, O-CMC were affected by the synthesis conditions. Structure of N, O-CMC was detected by fourier transform infrared spectrum (FTIR) and X-ray powder diffraction (XRD) was used to analyze the crystallinity. Potentiometric titration was used to measure the DS of N, O-CMC.

scholarly journals Enzymatic Synthesis and Characterization of Fructooligosaccharides and Novel Maltosylfructosides by Inulosucrase from Lactobacillus gasseri DSM 20604

2013 ◽  
Vol 79 (13) ◽  
pp. 4129-4140 ◽  
Author(s):  
Marina Díez-Municio ◽  
Blanca de las Rivas ◽  
Maria Luisa Jimeno ◽  
Rosario Muñoz ◽  
F. Javier Moreno ◽  
...  
Keyword(s):  
Reaction Time ◽  
Enzymatic Synthesis ◽  
Enzyme Concentration ◽  
Degree Of Polymerization ◽  
Sodium Acetate Buffer ◽  
Initial Amount ◽  
Content Type ◽  
Lactobacillus Gasseri ◽  
Synthesis Conditions

ABSTRACTThe ability of an inulosucrase (IS) fromLactobacillus gasseriDSM 20604 to synthesize fructooligosaccharides (FOS) and maltosylfructosides (MFOS) in the presence of sucrose and sucrose-maltose mixtures was investigated after optimization of synthesis conditions, including enzyme concentration, temperature, pH, and reaction time. The maximum formation of FOS, which consist of β-2,1-linked fructose to sucrose, was 45% (in weight with respect to the initial amount of sucrose) and was obtained after 24 h of reaction at 55°C in the presence of sucrose (300 g liter−1) and 1.6 U ml−1of IS–25 mM sodium acetate buffer–1 mM CaCl2(pH 5.2). The production of MFOS was also studied as a function of the initial ratios of sucrose to maltose (10:50, 20:40, 30:30, and 40:20, expressed in g 100 ml−1). The highest yield in total MFOS was attained after 24 to 32 h of reaction time and ranged from 13% (10:50 sucrose/maltose) to 52% (30:30 sucrose/maltose) in weight with respect to the initial amount of maltose. Nuclear magnetic resonance (NMR) structural characterization indicated that IS fromL. gasserispecifically transferred fructose moieties of sucrose to either C-1 of the reducing end or C-6 of the nonreducing end of maltose. Thus, the trisaccharide erlose [α-d-glucopyranosyl-(1→4)-α-d-glucopyranosyl-(1→2)-β-d-fructofuranoside] was the main synthesized MFOS followed by neo-erlose [β-d-fructofuranosyl-(2→6)-α-d-glucopyranosyl-(1→4)-α-d-glucopyranose]. The formation of MFOS with a higher degree of polymerization was also demonstrated by the transfer of additional fructose residues to C-1 of either the β-2,1-linked fructose or the β-2,6-linked fructose to maltose, revealing the capacity of MFOS to serve as acceptors.

scholarly journals Chemical Removal of Cu and Zn from Swine Feces before Soil Application

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 377
Author(s):  
Moo-Joon Shim ◽  
Seung-Mok Lee
Keyword(s):  
Reaction Time ◽  
H2so4 Solution ◽  
Optimum Conditions ◽  
Liquid Ratio ◽  
Optimal Method ◽  
Zn Concentration ◽  
Swine Feces ◽  
Removal Efficiencies ◽  
Cu And Zn ◽  
Oxalic Acids

Cu and Zn are known to be abundant in swine feces; hence, concentrations of these metals need to be lowered before swine feces are applied to land in order to prevent potential environmental problems. The main objective of this study was to develop an appropriate chemical process to remove Cu and Zn from swine feces using acid extractions. The removal efficiencies of Cu and Zn decreased in the order of H2SO4 > HNO3 > organic acids (citric and oxalic acids). Owing to the highest removal efficiencies of Cu and Zn by using H2SO4, it was selected for further elimination of Cu and Zn from swine feces. By using H2SO4, the optimal concentration, solid-to-liquid ratio, and reaction time were 2%, 1:50, and 8 h, respectively. At the optimum conditions, Cu concentration was decreased from 198 mg/kg to 40.1 mg/kg and Zn concentration from 474 mg/kg to 80.0 mg/kg, with removal rates of 79.7% and 83.1%, respectively. The low Cu removal efficiency, resulting from the strong complexation between Cu and organic matter of swine feces, was improved by the increase in the reaction time and H2SO4 solution concentrations. However, about half of the total nitrogen (TN) was also removed by using H2SO4, indicating that the swine feces treated with H2SO4 may have poor value as fertilizer. Additional studies are required to find an optimal method to maintain TN concentrations while simultaneously removing Cu and Zn.

Understanding of Lithium Insertion into λ-MnO2 Compounds

1998 ◽  
Vol 548 ◽  
Author(s):  
S. Sarciaux ◽  
A. Le Gal La Salle ◽  
A. Verbaere ◽  
Y Piffard ◽  
D. Guyomard
Keyword(s):  
Oxygen Content ◽  
Structural Parameters ◽  
Reversible Capacity ◽  
Rechargeable Batteries ◽  
Structural Water ◽  
Synthesis Conditions ◽  
Starting Compound ◽  
Physico Chemical ◽  
New Compounds

ABSTRACTA large variety of EMD and HTMD samples with various oxygen and water contents and various structural parameters Pr and Mt has been prepared. We show that the physico-chemical and structural parameters of the λ-MnO2 compounds are related to the synthesis conditions. New compounds were obtained with unusual amounts of intergrowth and twinning defects.The Li insertion study focuses on a comprehensive investigation of the relationships between the material characteristics of the samples and their Li insertion behavior, and on the structural characterization of selected compounds after cycling. The oxygen content drastically affects the shape of the discharge curve after the first cycle and the total reversible capacity. The amount of structural water has an influence on the transformation kinetics of the starting phase. For optimized oxygen content (y= 2 in MnOY), the intrinsic reversible Li insertion capacity is maximum when the amount of microtwinning defects is minimum and when the structure is either mostly Ramsdellite or faulted Pyrolusite. Results show that, upon cycling, the λ-MnO2 structure seems to evoluate towards less Pyrolusite defects together with the apparition of new kinds of defects.This work shows that λ-MnO2, compounds could be good candidates for the cathode application of Li-metal rechargeable batteries, provided that the physico-chemical and structural parameters of the starting compound are well chosen.

Degradation of chlorpyriphos in water by advanced oxidation processes

2010 ◽  
Vol 10 (1) ◽  
pp. 1-6 ◽  
Author(s):  
R. Murillo ◽  
J. Sarasa ◽  
M. Lanao ◽  
J. L. Ovelleiro
Keyword(s):  
Reaction Time ◽  
Light Source ◽  
Advanced Oxidation Processes ◽  
Advanced Oxidation ◽  
The Other ◽  
Molar Ratio ◽  
Optimum Conditions ◽  
Oxidation Processes ◽  
Other Hand ◽  
Initial Ph

The degradation of chlorpyriphos by different advanced oxidation processes such as photo-Fenton, TiO2, TiO2/H2O2, O3 and O3/H2O2 was investigated. The photo-Fenton and TiO2 processes were optimized using a solar chamber as light source. The optimum dosages of the photo-Fenton treatment were: [H2O2]=0.01 M; [Fe3 + ]=10 mg l−1; initial pH = 3.5. With these optimum conditions total degradation was observed after 15 minutes of reaction time. The application of sunlight was also efficient as total degradation was achieved after 60 minutes. The optimum dosage using only TiO2 as catalyst was 1,000 mg l−1, obtaining the maximum degradation at 20 minutes of reaction time. On the other hand, the addition of 0.02 M of H2O2 to a lower dosage of TiO2 (10 mg l−1) provides the same degradation. The ozonation treatment achieved complete degradation at 30 minutes of reaction time. On the other hand, it was observed that the degradation was faster by adding H2O2 (H2O2/O3 molar ratio = 0.5). In this case, total degradation was observed after 20 minutes.

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