Effect of Surface Oxygen Complexes of Activated Carbon on the Adsorption of 2,4,6- Trinitrophenol

The adsorption isothenns for 2,4,6-trinitrophenol (picric acid) on five samples of coconut-based activated carbons (ACs) with varying. surface area have been studied. The results obtained show thatadsorption depends upon surface area but is not linearly related to it. The adsorption increases on oxidation with ammonium persulphate (NH4)2 S2 08) as well as on degassing at 600 °C. The resultshave been explained on the basis of the existence of surface carbonyl groups, where the 02 of thecarbonyl group interacts with pi electrons of the benzene ring of picric acid

Removal of arsenic from water by different adsorbents

518-525Present study is carried out for the removal of As(III) from water using commonly available adsorbents such as sand, from Yamuna river (Delhi ), as well as from Ganga river (Kolkata), activated carbon, Hametite ore and sand -iron scrap mixture. All these adsorbents are used as received but sand and activated carbon which do not show much adsorption for As(III) are modified by treating with different metal ions in order to improve their adsorption efficiency. Results of the laboratory experiments under static conditions have confirmed that iron impregnated granular activated carbon (GAC), spherical activated carbon (SAC) as well as sand - iron scrap mixture have much promise as a medium for the removal of As(III) in drinking water. Various parameters like adsorbent dose, contact time, pH and arsenic concentration are optimized. A simple and economical domestic arsenic removal kit has been designed and successfully evaluated in the laboratory using sand-iron scrap mixture as media for the removal of arsenic from water

Adsorption of styphnic acid on activated carbon

42-44<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">The adsorption isotherms of styphnic acid from aqueous solutions in the concentration range of 20- 700 mg/L have been studied on five different commercially available coconut based activated carbons having surface area between 650-1300 m2/g. Adsorption of styphnic acid depends on the surface area of the activated carbon. However, the monolayer coverage per unit area increases up to a surface area of 1000 m2/g and exhibits a slight decrease thereafter. The effect of varying amounts of carbon-oxygen surface complexes created by oxidation and elimination by degassing treatments, on the adsorption of styphnic acid indicates that the increase in adsorption is linearly related to the amount of oxygen on the surface of activated carbons.</span

Adsorption isotherm studies of trinitrotoluene on granular activated carbon from aqueous solution

87-90<span style="font-size:11.0pt;line-height:115%; font-family:" calibri","sans-serif";mso-ascii-theme-font:minor-latin;mso-fareast-font-family:="" "times="" new="" roman";mso-fareast-theme-font:minor-fareast;mso-hansi-theme-font:="" minor-latin;mso-bidi-font-family:"times="" roman";mso-ansi-language:en-us;="" mso-fareast-language:en-us;mso-bidi-language:ar-sa"="">This paper presents the adsorption isotherm studies on coconut based activated carbon (AC) of different grades (650-1300 m2/g) to asses its efficiency for the removal of trinitrotoluene (TNT) from aqueous solutions. Freundlich and Langmuir adsorption isotherms are plotted and equilibrium constant and maximum adsorption capacity for each carbon is computed from the isotherm data. A linear relationship has been obtained between amount adsorbed and the surface area of carbons. The effect of varying amounts of carbon oxygen complexes on carbon surface modified by oxidation and degassing treatments, on the adsorption of TNT has also been studied. The results indicate that the increasing amount of chemisorbed oxygen on carbon has favourably influenced the adsorption behaviour of TNT.</span