Commenced in January 2007
Frequency: Monthly
Edition: International
Paper Count: 3

adsorbents Related Abstracts

3 Biosorption of Heavy Metals by Low Cost Adsorbents

Authors: Azam Tabatabaee, Fereshteh Dastgoshadeh, Akram Tabatabaee

Abstract:

This paper describes the use of by-products as adsorbents for removing heavy metals from aqueous effluent solutions. Products of almond skin, walnut shell, saw dust, rice bran and egg shell were evaluated as metal ion adsorbents in aqueous solutions. A comparative study was done with commercial adsorbents like ion exchange resins and activated carbon too. Batch experiments were investigated to determine the affinity of all of biomasses for, Cd(ΙΙ), Cr(ΙΙΙ), Ni(ΙΙ), and Pb(ΙΙ) metal ions at pH 5. The rate of metal ion removal in the synthetic wastewater by the biomass was evaluated by measuring final concentration of synthetic wastewater. At a concentration of metal ion (50 mg/L), egg shell adsorbed high levels (98.6 – 99.7%) of Pb(ΙΙ) and Cr(ΙΙΙ) and walnut shell adsorbed high levels (35.3 – 65.4%) of Ni(ΙΙ) and Cd(ΙΙ). In this study, it has been shown that by-products were excellent adsorbents for removal of toxic ions from wastewater with efficiency comparable to commercially available adsorbents, but at a reduced cost. Also statistical studies using Independent Sample t Test and ANOVA Oneway for statistical comparison between various elements adsorption showed that there isn’t a significant difference in some elements adsorption percentage by by-products and commercial adsorbents.

Keywords: wastewater, Heavy Metals, adsorbents, by-products, commercial adsorbents

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2 Synthesis of Amine Functionalized MOF-74 for Carbon Dioxide Capture

Authors: Ghulam Murshid, Samil Ullah

Abstract:

Scientific studies suggested that the incremented greenhouse gas concentration in the atmosphere, particularly of carbon dioxide (CO2) is one of the major factors in global warming. The concentration of CO2 in our climate has crossed the milestone level of 400 parts per million (ppm) hence breaking the record of human history. A report by 49 researchers from 10 countries said, 'Global CO2 emissions from burning fossil fuels will rise to a record 36 billion metric tons (39.683 billion tons) this year.' Main contributors of CO2 in to the atmosphere are usage of fossil fuel, transportation sector and power generation plants. Among all available technologies, which include; absorption via chemicals, membrane separation, cryogenic and adsorption are in practice around the globe. Adsorption of CO2 using metal organic frameworks (MOF) is getting interest of researcher around the globe. In the current work, MOF-74 as well as modified MOF-74 with a sterically hindered amine (AMP) was synthesized and characterized. The modification was carried out using a sterically hindered amine in order to study the effect on its adsorption capacity. Resulting samples were characterized by using Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Thermal Gravimetric Analyser (TGA) and Brunauer-Emmett-Teller (BET). The FTIR results clearly confirmed the formation of MOF-74 structure and the presence of AMP. FESEM and TEM revealed the topography and morphology of the both MOF-74 and amine modified MOF. BET isotherm result shows that due to the addition of AMP in to the structure, significant enhancement of CO2 adsorption was observed.

Keywords: Global Warming, CO2, adsorbents, amine

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1 Application of Synthetic Monomers Grafted Xanthan Gum for Rhodamine B Removal in Aqueous Solution

Authors: Tshepiso Moremedi, Lebogang Katata-Seru, Soumen Sardar, Abhijit Bandyopadhyay, Edwin Makhado, Mpitloane Joseph Hato

Abstract:

The rapid industrialisation and population growth have led to a steady fall in freshwater supplies worldwide. As a result, water systems are affected by modern methods upon use due to secondary contamination. The application of novel adsorbents derived from natural polymer holds a great promise in addressing challenges in water treatment. In this study, the UV irradiation technique was used to prepare acrylamide (AAm) monomer and acrylic acid (AAc) monomer grafted xanthan gum (XG) copolymer. Additionally, various factors affecting rhodamine B (RhB) adsorption from an aqueous medium such as pH, adsorbent dose, initial dye concentration, solution temperature and contact time were investigated. The FTIR results confirmed the formation of graft copolymer between AAm and AAc. The SEM showed some irregular, porous and wrinkled surface morphology of XG-g-pAAm-co-AAc indicating successful copolymerization of the reacting monomers. The optimum conditions for removing RhB dye with a maximum adsorption capacity of 313 mg/g at 25 oC and pH 5 was obtained. The adsorption of RhB followed Freundlich’s model in all cases. Kinetic studies indicated that the pseudo-second-order model can be employed for describing the dynamics of the adsorption process. Therefore, grafted XG has tremendous potential to be used as an adsorbent to remove cationic dyes from aqueous solutions.

Keywords: adsorbents, rhodamine B, freundlich, xanthan gum

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