NISCAIR Online Periodicals Repository Collection: IJEMS Vol.17(5) [October 2010]

Phosphorylated tamarind nut carbon for the removal of cadmium ions from aqueous solutions

Tue, 28 Sep 2010 22:58:59 GMT

Title: Phosphorylated tamarind nut carbon for the removal of cadmium ions from aqueous solutions

Authors: Suganthi, N; Srinivasan, K

Abstract: Activated carbon prepared from phosphoric acid treatment of Tamarind nuts (seeds) is investigated for the removal of cadmium ions from aqueous solutions. Carbon granules of 300 to 800 µm particle size are chosen for all studies. The characteristics of the phosphorylated tamarind nut carbon (PTNC) are evaluated for porosity, surface area, iodine number, phenol number, moisture content and decolorizing power. PTNC is subjected to the adsorption of cadmium ions from aqueous solution. The effects of pH, contact time, metal ion concentration and carbon dosage are studied to evaluate the potential applicability of carbon produced as an adsorbent for wastewater treatment. The adsorption data are modeled by using Langmuir and Freundlich classical adsorptions isotherms. Kinetic studies fitted best with pseudo-second order model. Desorption studies indicated that ion-exchange mechanism is operating. Column studies are conducted in 2.5 cm diameter columns. Under optimum conditions of flow rate and bed height, breakthrough capacities are found out. The mechanism of adsorption for cadmium on PTNC is found to follow ion exchange process predominantly and supported by FTIR. The cadmium removal and the surface modification are also confirmed by SEM studies.

Page(s): 382-388

Uptake of toxic metals from wastewater by activated carbon from agro industrial by-product

Tue, 28 Sep 2010 22:58:59 GMT

Title: Uptake of toxic metals from wastewater by activated carbon from agro industrial by-product

Authors: Hema, M; Srinivasan, K

Abstract: Activated carbon prepared from neem oilcake, by pyrolysis accompanied with microwave oven activation is evaluated for the adsorption of Cd(II) and Ni(II) from wastewater. Parameters such as pH, agitation time, metal ion concentration and adsorbent dose are studied. The percent removal increased with pH from 2.0 to 7.0. The adsorption data fit well with Langmuir, Freundlich and Temkin isotherm models. The adsorption capacity (q_e) calculated from Langmuir isotherm are 54.95 mg Ni(II)/g and 23.70 mg Cd(II)/g at an optimal pH of 7.0 at 30°C for the particle size 0.120-0.075 mm. Adsorption of Cd(II) and Ni(II) by activated carbon from neem oilcake follows pseudo-second-order kinetic model. Desorption studies with dilute hydrochloric acid indicate that quantitative recovery of cadmium and nickel ions are possible. The mechanism of adsorption seems to follow ion exchange process. As neem oilcake is discarded as waste from oil processing industries, the carbon could be exploited for metal ions recovery from wastewater.

Page(s): 373-381

Dynamic adsorption of Pb(II) ions from aqueous solution using activated carbon beds

Tue, 28 Sep 2010 22:58:59 GMT

Title: Dynamic adsorption of Pb(II) ions from aqueous solution using activated carbon beds

Authors: Goyal, Meenakshi; Bhagat, Mamta

Abstract: The dynamic adsorption of Pb(II) ions from aqueous solutions using a granulated activated carbon and an activated carbon cloth has been studied using fixed bed adsorption column. The breakthrough curves at different hydraulic loading rates (HLR), bed depth and feed concentration (C_o) have been examined. The breakthrough time at any given concentration of the effluent decreases with increasing hydraulic loading rate and feed concentration but increases with increasing bed depth. The adsorption capacity of the carbon bed increases with increasing HLR and attains a maximum value at HLR of 1.22 m³/h/m². The adsorption zone parameters and column design parameters have been determined using BDST, Yoon-Nelson and Wolborska models. The experimental values obtained from column experiments agree fairly with the theoretical values obtained using different equations. The design parameters obtained from one column experiment have been used to design adsorption column for any other flow rate and feed concentration.

Page(s): 367-372

Investigation on magnetic carbon nanofoam composites

Tue, 28 Sep 2010 22:58:59 GMT

Title: Investigation on magnetic carbon nanofoam composites

Authors: Pant, R P; Arora, Manju; Lal, Chhotey; Annveer; Singh, Sukhvir; Mathur, R B

Abstract: Magnetic carbon nanofoam composites have been synthesized by employing electric arc discharge using nano-crystalline 1% by weight cobalt ferrite particles as catalyst. The material formed is a short-range fluffy type arrangement of carbon embedded with nano-magnetic particles. The volume percent of carbon is ~ 85% in the composite material and the density is ~ 0.8 g/cm³. Material has been characterized for its physical properties like structural, magnetic, shape and size distribution by XRD, TEM, SAXS, EPR and VSM measurement techniques. The prepared composite has low density, electrically conducting and soft magnetic properties. The developmental studies of magnetic carbon nanofoam process have been described.

Page(s): 363-366