Adsorption of <i>Pb (II)</i> and <i>Cd (II)</i> Ions from Their Aqueous Solutions unto Carbonised Orange Peels

Abstract

The presence of heavy metals in the environment and especially water is known to both cause severe harm to marine organisms, and also to terrestrial plants and animals including human beings. In an attempt to minimize environmental pollution caused by agricultural wastes and maximize agricultural by-products, the adsorption of Pb²⁺ and Cd²⁺ using carbonized orange peel as adsorbent was studied using batch adsorption method. The initial physico-chemical properties of the prepared adsorbent were 6.14, 10%, 12%, 2.0%, and 0.5mg/L for pH, attrition, ash content, moisture content and bulk density respectively. Atomic adsorption spectrophotometer was used to monitor the Pb²⁺ and Cd²⁺ concentrations of the simulated test solutions. The optimum values obtained were 97.34% at concentration of 40mg/L for Pb²⁺ and 93.45% at concentration of 20mg/L for Cd²⁺, 99.46% at a pH of 7 for Pb²⁺ and 97.48% at a pH of 6 for Cd²⁺, 96.76% at a contact time of 80 mins for Pb²⁺ and 50.05% at a contact time of 100 mins for Cd²⁺ and 97.36% at an adsorbent dosage of 1.2g for Pb²⁺ and 91.55% at an adsorbent dosage of 1.2g for Cd²⁺. The results indicated that carbonized orange peel is a good adsorbent for the removal Pb²⁺ and Cd²⁺ from simulated waste water.