Adsorption kinetics of cadmium ions onto powdered corn cobs

Abstract

Environmental pollution caused by the presence of toxic materials such as cadmium is becoming global problem and concern. This paper presents a report on kinetics of Cd 2+ removal from aqueous solutions through adsorption using powdered corn cobs (PCC). Corn cobs were collected from a selected location, washed to remove sand, air dried, ground and sieved into different particle sizes. The selected properties of PCC were determined using acid digestion method. Adsorption capacities through kinetics of Cd 2+ removal from synthetic solutions, typical raw water and domestic-institutional wastewater were studied. Effects of pH, PCC particle size, initial concentration of Cd 2+ and temperature on adsorption capacities were monitored through pseudo first-and second-order models, Elovich and intraparticle diffusion models to present adsorption rate parameters.The study revealed that PCC contained 86.89% volatile solids, had 4.56% acid solubility, 0.52 water solubility and 2.33% ash content. PCC removed Cd 2+ from aqueous solutions (synthetic, raw water, and wastewater). The relationship between time and concentration of Cd 2+ remaining in the solution followed exponential functions with squared correlation coefficient ranging from 0.9928 to 0.9993, 0.8701 to 0.9284, and 0.8514 to 0.9290 for synthetic solution, raw water, and typical domestic-institutional wastewater, respectively. Mechanism of cadmium adsorption onto PCC was in two separate stages linear portions in the first parts, while the final parts are curves indicating intraparticle diffusion. It was concluded that PCC is an effective adsorbent for Cd 2+ removal. The estimated production cost was 0.068 USD as against 0.50, 2.12, and 3.12 USD for producing adsorbents from empty fruit bunches; pencom shell and sugar cane based activated carbons, respectively.Cet article présente un rapport sur la cinétique du retrait du Cd2+ de solutions aqueuses par adsorption en utilisant de la rafle de maïs en poudre (RMP). Lesépis de maïs ontété collectésà partir d'un lieu sélectionné, lavés pouréliminer le sable, séchésà l'air, broyés et tamisés en particules de différentes tailles. Les propriétés sélectionnées de la RMP ontété déterminées en utilisant la méthode de la digestion acide. On aétudié les capacités d'adsorption par la cinétique du retrait du Cd2+ de solutions synthétiques, d'eaux brutes non traitées et d'eaux usées ménagères-institutionnelles. Les effets du pH, de la taille des particules de RMP, de la concentration initiale de Cd2+ et de la température sur les capacités d'adsorption ontété suivis par des modèles de pseudo-cinétique de premier ordre et de second ordre, Elovich et des modèles de diffusion intra-particule pour présenter des paramètres de taux d'adsorption. L'étude révèle que la RMP contenait 86,889% de solides volatils, avait une solubilité dans l'acide de 4,56%, une solubilité dans l'eau de 0,52 et une teneur en cendres de 2,331%. La RMP permettait de retirer le Cd2+ des solutions aqueuses (synthétiques, eau brute et eaux usées). La relation entre le...

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