title: Removal of cadmium(II) from wastewater using activated carbon prepared from Agro Industrial by-products.
abstract: Removal of cadmium from wastewater using activated carbons prepared from Cocos nucifera (coconut) and Azadirachta indica (neem) oilcakes-an agricultural solid by-product was investigated. Batch experiments were performed to evaluate the effect of pH, agitation time, initial metal ion concentration and adsorbent dose on the cadmium sorption in coconut oil cake activated carbon (COCAC) and neem oil cake activated carbon (NOCAC). The experiments demonstrated that the adsorption process corresponds to the pseudo-second-order-kinetic model and the equilibrium adsorption data fit well with Temkin isotherm model. The adsorption capacity 'b' calculated from the Langmuir isotherm was 188.68 mg/g for COCAC and 23.7 mg/g for NOCAC. The percent removal of Cd(II) in COCAC increased in pH from 2 to 5, and remained constant up to pH 8, increasing the percent removal with increasing pH for NOCAC. Desorption studies were performed with 0.1M hydrochloric acid. It was found that quantitative recovery of the metal ion is possible. It was also observed that the mechanism of adsorption seems to be ion exchange. Reuse of both carbons were carried out for five cycles at optimum conditions. Adsorption efficiency of carbons was reduced from 99 to 89% in the case of COCAC and 97 to 86% for NOCAC.
authors.affiliation: Department of Chemistry, College of Engineering, Anna University-Coimbatore, Salem, 636 011, Tamil Nadu, India.
authors.forename: M
authors.initials: M
authors.lastname: Hema
authors.forename: K
authors.initials: K
authors.lastname: Srinivasan
mesh_terms: D000042:Absorption; D000383:Agriculture / Q000379:methods; D002104:Cadmium / Q000302:isolation & purification*; D002606:Charcoal / Q000737:chemistry*; D003247:Conservation of Natural Resources / Q000379:methods; D007220:Industrial Waste / Q000517:prevention & control*; D010936:Plant Extracts / Q000737:chemistry*; D014462:Ultrafiltration / Q000379:methods*; D014874:Water Pollutants, Chemical / Q000302:isolation & purification*; D018508:Water Purification / Q000379:methods*
chemical_list: C518724:CML-1 plant extract; D007220:Industrial Waste; D010936:Plant Extracts; D014874:Water Pollutants, Chemical; D002104:Cadmium; D002606:Charcoal