The removal of heavy metals by using agricultural wastes

Abstract

The removal of heavy metals from wastewater using adsorbants such as waste tea, Turkish coffee, exhausted coffee, nut and walnut shells has investigated. Batch studies were conducted at room temperature and adsorption experiments were carried out by shaking 0.3 g of adsorbent with 100 ml synthetic wastewater containing Cr (VI), Cd (II) and Al (III) metal ions. The remaining concentration of heavy metals in each samples after adsorption at various time intervals was determined spectrophotometrically. Batch studies showed that these adsorbents exhibit a good adsorption potential for Al (III) metal ions. The adsorption ratios of Al(III) were as 98, 99, 96, 99.5 and 96% for waste tea, Turkish coffee, exhausted coffee, nut and walnut shells, respectively. These results were compared with those obtained using activated carbon as adsorbent. The batch adsorption kinetics and adsorption equilibria were examined and described by a first order reversible reaction and Freundlich isotherm, respectively. The first order rate and isotherm constants have been calculated.