scholarly journals Semi-refined k-carrageenan: Part 1. Chemical Modification of Semi-refined ?-carrageenan via Graft Copolymerization Method, Optimization Process and Characterization of its Superabsorbent Hydrogel

2015 ◽  
Vol 31 (2) ◽  
pp. 973-980 ◽  
Author(s):  
Jamaluddin Daud ◽  
Nor Shuhadah Warzukni ◽  
Rosliza Salim ◽  
Ahmad Zuberdi
Keyword(s):  
Chemical Modification ◽  
Graft Copolymerization ◽  
Optimization Process ◽  
Superabsorbent Hydrogel ◽  
Method Optimization

scholarly journals Preparation and Characterization of the Sulfur-Impregnated Natural Zeolite Clinoptilolite for Hg(II) Removal from Aqueous Solutions

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 217
Author(s):  
Marin Ugrina ◽  
Martin Gaberšek ◽  
Aleksandra Daković ◽  
Ivona Nuić
Keyword(s):  
Chemical Modification ◽  
Aqueous Solutions ◽  
Specific Surface ◽  
Surface Area ◽  
Natural Zeolite ◽  
Contact Time ◽  
Liquid Ratio ◽  
X Ray ◽  
Solid Liquid

Sulfur-impregnated zeolite has been obtained from the natural zeolite clinoptilolite by chemical modification with Na2S at 150 °C. The purpose of zeolite impregnation was to enhance the sorption of Hg(II) from aqueous solutions. Chemical analysis, acid and basic properties determined by Bohem’s method, chemical behavior at different pHo values, zeta potential, cation-exchange capacity (CEC), specific surface area, X-ray powder diffraction (XRPD), scanning electron microscopy with energy-dispersive X-ray analysis (SEM-EDS), Fourier transform infrared spectroscopy (FTIR), as well as thermogravimetry with derivative thermogravimetry (TG-DTG) were used for detailed comparative mineralogical and physico-chemical characterization of natural and sulfur-impregnated zeolites. Results revealed that the surface of the natural zeolite was successfully impregnated with sulfur species in the form of FeS and CaS. Chemical modification caused an increase in basicity and the net negative surface charge due to an increase in oxygen-containing functional groups as well as a decrease in specific surface area and crystallinity due to the formation of sulfur-containing clusters at the zeolite surface. The sorption of Hg(II) species onto the sulfur-impregnated zeolite was affected by the pH, solid/liquid ratio, initial Hg(II) concentration, and contact time. The optimal sorption conditions were determined as pH 2, a solid/liquid ratio of 10 g/L, and a contact time of 800 min. The maximum obtained sorption capacity of the sulfur-impregnated zeolite toward Hg(II) was 1.02 mmol/g. The sorption mechanism of Hg(II) onto the sulfur-impregnated zeolite involves electrostatic attraction, ion exchange, and surface complexation, accompanied by co-precipitation of Hg(II) in the form of HgS. It was found that sulfur-impregnation enhanced the sorption of Hg(II) by 3.6 times compared to the natural zeolite. The leaching test indicated the retention of Hg(II) in the zeolite structure over a wide pH range, making this sulfur-impregnated sorbent a promising material for the remediation of a mercury-polluted environment.

Synthesis and characterization of SPE membrane based on sulfonated FEP-g-acrylic acid by radiation induced graft copolymerization for PEM fuel cell

2004 ◽  
Vol 15 (5) ◽  
pp. 270-274 ◽  
Author(s):  
M. Patri ◽  
Varsha R. Hande ◽  
Swati Phadnis ◽  
B. Somaiah ◽  
Suhasini Roychoudhury ◽  
...  
Keyword(s):  
Fuel Cell ◽  
Acrylic Acid ◽  
Graft Copolymerization ◽  
Pem Fuel Cell ◽  
Synthesis And Characterization ◽  
Radiation Induced

scholarly journals Materials characterization of TiO2 nanotubes decorated by Au nanoparticles for photoelectrochemical applications

RSC Advances ◽  
2021 ◽  
Vol 11 (61) ◽  
pp. 38727-38738
Author(s):  
Marcin Pisarek ◽  
Mirosław Krawczyk ◽  
Andrzej Kosiński ◽  
Marcin Hołdyński ◽  
Mariusz Andrzejczuk ◽  
...  
Keyword(s):  
Chemical Modification ◽  
Tio2 Nanotubes ◽  
Au Nanoparticles ◽  
Materials Characterization ◽  
Analytical Measurements

The structural and chemical modification of TiO2 NTs by the deposition of a well-controlled Au deposit (0.01 mg cm−1) was investigated using a combination of microscopic (SEM, STEM), analytical measurements (XPS, SERS, UV-Vis, XRD) and photoelectrochemical investigations.

Preparation and characterization of oxidized starch-graft-poly(styrene-butyl acrylate) latex via emulsion polymerization

2014 ◽  
Vol 34 (7) ◽  
pp. 611-616 ◽  
Author(s):  
Shijie Cheng ◽  
Jun Xu ◽  
Yumin Wu
Keyword(s):  
Emulsion Polymerization ◽  
Butyl Acrylate ◽  
Colloidal Stability ◽  
Graft Copolymerization ◽  
Scanning Calorimetry ◽  
Oxidized Starch ◽  
Ir Transmission ◽  
Ft Ir ◽  
Synthetic Latex

Abstract Oxidized starch-graft-poly(styrene-butyl acrylate) [OS-g-P(St-BA)] latex was synthesized by the graft copolymerization of OS with St and n-butyl acrylate (BA) via emulsion polymerization. The graft copolymers were characterized by Fourier transform infrared (FT-IR), transmission electronic microscopy (TEM), dynamic light scattering, thermogravimetry (TG), and differential scanning calorimetry (DSC). The effects of the amount of OS, monomers, and initiator on graft copolymerization were investigated. Under the optimal conditions, the percentage of graft (PG), grafting efficiency (GE), and ζ potential could reach 256.5%, 41.7%, and -30.1 mV, respectively. The results indicated that the OS grafted onto particles greatly enhanced the colloidal stability of latex. The thermal stability properties of OS-g-P(St-BA) were also improved by the addition of OS. The OS-g-P(St-BA) latex may be used to partly replace the conventional synthetic latex for paper coating.

Sign in / Sign up

Export Citation Format

Share Document